Edition DETAIL - Construction Materials Manual

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Parameters of an expanded polystyrene foam and the various contributions to heat conduction Thermal conductivities of IR absorber-modified EPS in comparison to conventional EPS depend­ ing on the density The principle of infrared absorption The principle of nanocellular foam a Macrofoam: cell gas has a large influence on thermal conductivity b Nanofoam: cell gas has no influence on thermal conductivity

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A phase change material (PCM) i s a substance in which heat is stored by means of a phase transition (e.g. sol id to liquid). The temperature of the material remains constant until the phase transition has been completed. The stored heat (or cold) is invisi ble, but present in a latent state. Such materials have been known for a long time. [ 1 1 ] For example, the use of ice to cool a drink is an application of the phase change principle: as long as the ice melts, the drink remains cool because the heat is used to melt the ice. However, in order to master this principle on a technical level , some development work was necessary first. Materials with a phase transi­ tion in the desired temperature range had to be found, and these then had to be housed in cor­ responding containers because the storage of heat is generally associated with a melting of the material. In the first applications solar heat was stored in tanks filled with salt hydrates techn ically elaborate and offering l ittle flexi b i lity for practical applications. Later, paraffin was used as an alternative; paraffin can be stored in sealed plastic containers and panels. One of the first applications of this macro­ encapsulated phase change material was i n Switzerland. "Solar House 1 1 " in Ebnat-Kappel by Dietrich Schwarz has a heat storage ele­ ment consisting of paraffin-filled plastic boxes fitted into a g lass wal l , which acts as a buffer against excessive heat in the summer, and as a solar energy store in the winter. A cleverly arranged prism in front of the phase change material prevents overheatin g in summer and enables the heat gains in winter. [ 1 2 ] The most obvious next - technology-driven step was to transfer the encapsulation to the microscopic level. The first attempts using

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W/mK can be achieved - values wel l below those of conventional insulating materials. Such vacuum insulation panels are already on the market. Their potential applications are current­ ly being i nvestigated more closely in various pilot projects. We are on the brink of an i nnova­ tion. One disadvantage of these elements is their vulnerabil ity to mechanical damage, which calls for great care during installation. How­ ever, such systems have already been used in industrially prefabricated appliances, e.g. refrigerators. Nanocellular foams could have a high insulat­ ing effect simi lar to that of VIP and wou ld be less vulnerable to mechan ical damage. These foams exploit the effect that if the size of the cell is small enough, each cell contains just one single gas molecule, which would be more or less "frozen" (fi g . A 5.6) . However, such foams cannot yet be produced on an industrial scale. But should this succeed , their techn ical proper­ ties would be equal to those of conventional foams, al beit with a much reduced thermal conductivity. The marketing success or other­ wise of this invention has sti l l to be tested .

A 5.6

melamine were carried out in the USA. These microcapsules containing a phase change material are used, for instance, in special cloth­ ing. For the building industry in particular, sev­ eral German companies and institutes have developed formaldehyde-free systems based on methyl acrylate within the scope of a joint project. [ 1 3] Using micro-encapsulated paraf­ fins (fi gs A 5. 1 1 and A 5 . 1 2) , it has been possi­ ble to incorporate phase change materials into building materials like plaster, plasterboard and particleboards (fig . A 5.8). PCMs are very good at preventing overheating in summer. I n itial applications show that this passive cool­ ing functions marvel lously. Properly integrated into the energy design criteria, their use results in lower capital outlay (thanks to smaller refrig­ eration plant) and lower operating costs (thanks to lower refrigeration output). On the other side of the equation, such materials are more expensive. In the near future we will see just how far the economic appeal of PCMs can guarantee their market success; such materials are sti l l at the market development stage. What is certain, however, is that cooling systems with PCMs will make a significant contribution to the energy efficiency of buildings within the scope of sustainable development. There are other fields of innovation that could become interesting in the coming years: •

•

•

·

energy management - saving on heating and cooling energy "easy-to-clean" - cleaning of surfaces "easy-to-hand le" - l i ghtweight, foolproof pro­ ducts, especially for renovation and moderni­ sation interior climate and wel l ness - low-emissions products, the feel of surfaces

Although the solutions will be based on tech­ nology, soft factors, too, wi l l have to be consid­ ered for their application. Establishment of innovations in the future

The examples described above demonstrate the technologically motivated development of new materials: technically definable properties such as heat conduction or heat capacity were able to be improved . The materials described are functional , they carry out their work in the building invisibly. Their aesthetic or haptic qual ities are not the result of a design process, but rather a product of their properties. In the marketing of these materials it is there­ fore the techn ical quality that is critical - and hence the leeway for further marketing is limit­ ed. But by considering soft factors this leeway could be expanded; at the same time, it should be possible to achieve a more targeted devel­ opment of innovative materials. In product development it is only in the final phases that we find out whether an invention wi l l really become an i nnovation. The influence of pure technology is large at the start and

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decreases towards the end. I nverse to this is the opportunity for the architect - as the repre­ sentative of the end market - to influence the development. It would seem obvious that by involving all the participants in the value-crea­ tion chain at an early stage, hitherto unrecog­ nised chances can be created (fi g . A 5 . 7 ) : expensive mistakes c a n be avoided or even misguided developments prevented right at the development phase. It is essential to find a rea­ sonable balance here between the justified wish for exclusivity on an artistic level and the equally justified interests of industry for a sus­ tainable economic success, which is based on the widespread use of a material. If this is successfu l , the combination of techno­ logical skills in the raw materials and building materials industries with the system, process and design expertise of the others in the con­ struction team can discover whole new approaches to inventions and i nnovations.

A 5.7 References:

[1)

[2) [3) [4) (5)

[6) (7) [8)

Innovation survey of the Competition Research Centre, Swiss Federal I nstitute of Technology, Zurich, 1 999 Schumpeter, Joseph: Theorie der wirtschaftlichen Entwicklung. Berlin 1 987 www.innovationen-fuer-deutschland.de For further literature see pp. 272-74 Material ( . . . ): substance, raw material, medium; also: total of available aids, objects, documents needed to produce somethin 9 , for work, as equipment or similar. In business management the initial materials for production, which include raw materials, aids and operational resources, reusable residual mate­ rials plus semi-finished and finished goods which are incorporated into the industrial production process. Source: Brockhaus - Die Enzyklopadie in 24 Ban­ den, Leipzig/Mannheim, 1 996--99 McGraw Hill: The Top International Constructors. August 2004 de Solla Price, Derek John: Little Science - Big Science. New York 1 963 K6lbel, Matthias: Das Wachstum der Wissenschaft in Deutschland 1 650-2000. In: Parthey, Heinrich; Spur, Gunter (ed.): Wissenschaft und Innovation - Wissen­ schaftsforschung Jahrbuch 2001 . Berlin 2002

[9) [ 1 0)

[1 1 )

[12) [ 1 3)

A 5.8 Marx, Werner; Gramm, Gerhard: Literaturflut - Infor­ mationslawine - Wissensexplosion. Stuttgart 2002 This trend of the "usability" of research results in the meantime accompanies even fundamental research. Generally, research applications are no longer approved if not accompanied by ideas regarding possible applications. BINE-Informationsdienst des Fachinformations­ zentrums Karlsruhe, themeninfo IVl02, (www.bine. info) provides a 900d overview of PCMs See also Detail 06/2002, p. 736 Federal Ministry of Education & research: joint pro­ ject together with BASF, maxit, Caparol, Sto and the Fraunhofer Institute for Solar Energy Systems (ISE)

Assistants: Dr. Jurgen Fischer, Ludwigshafen, Dr. Ekkehard Jahns, Ludwigshafen, Dr. Peter Eckerle, Ludwigshafen

A 5.7

a Schematic innovation chain b Targeted innovation through early integration of the end market A 5.8 Layer thicknesses of different materials for the same heat storage capacity A 5.9 The surface of a graphite-modified polystyrene A 5 . 1 0 Open-pore melamine resin foam: the pores that enable the exchange of gas are clearly visible. A 5. 1 1 Micro-encapsulated paraffin in crystalline state A 5 . 1 2 Micro-encapsulated paraffin in molten state

31

Touching the senses materials and haptics in the design process Marc Esslinger

For a number of years, haptics (Greek: hap­ to grasp, touc h ) , the branch of science dealing with the sense of touch, has been makin g significant inroads into the research and development projects of many companies i nvolved i n marketing, archi­ tecture and desi g n . The role haptic aspects play in the design of products and how they interact with other design criteria such as aes­ thetics, material, brand-name relevance and competitive environment is the theme of this chapter. Basically, design is a generalist approach, and the decision-making process is subject to numerous influences, comparable with the work in an architectural practice. Therefore, at this point we shall demonstrate the aspects and experiences of industrial design that are interesting for the architect's way of thinkin g , a n d stimulate a discussion between these related disciplines. tikos, from haptesthai

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Sensual stimuli an d the specific addressing of new communication channels

Advertising deliberately plays with our senses. Traditional advertising was followed by moving images, and today acoustic signals are used as wel l . Passing through airports and railway stations, for instance, repetitive three-part chords i mprint themselves on our brains and we start to associate them with certain brands and services - whether we like it or not. The consumer cannot simply shut out the sound in

A 6.1

A 6.2

A 6.3 A 6.4

the same way that he or she flicks past the pages of advertisements in magazines. In this method , called penetration, the aim is frequent­ ly to attract attention for the sake of it rather than to generate a positive feeling in the addressee. This is due not just to the short­ lived nature of many campaigns, but instead to the fact that much advertising is built on illu­ sions anyway and not on the actual uses or benefits of a product or a service. Architects claim to think long-term, after all, the product to be created should remain relevant for more than just a fraction of a second. In the case of designers, the spectrum of products to be designed ranges from short-lived consumer goods right up to worthwhile products for med i­ cal technology or the san itary industry, which should remain modern and timeless for half a lifetime and, above all, should not break. It is said that many creative persons are really rather conservative in their private lives. Does this result in a desire to cling to objects and not only illusions? I n the reasoned assumption that this is true for many people, deSigners config­ ure products we not only use, but do so with a recurring delight. The work of design agencies is becoming ever more complex, but also more exciting. For a long time now, design has meant more than just painting pictures, more than just pure beautification. "Design is a strategic means in the i mplementation of corporate objectives" is

"Touch test": to test the haptic experience, the "frog design" agency works with different material samples. Pipette developed for the Vista lab company: the ergonomic shape is based on its application in the laboratory. "Prana" shoe with integral massage function Orangina bottle: form and surface reminiscent of a citrus fruit A 6. 1

32

Touching the senses - materials and haptics in the design process

the smart definition of the professional activities in the legendary 1 0-second meetings in the l ifts of skyscrapers in Hamburg, Paris or New York. This means constraints: costs, target prices, ever shorter product l ife cycles. But it also means more freedom because design enjoys more i mportance within the company. Product designers must try to absorb marketing con­ cepts, but they must also be able to assess technical feasibility and understand the manu­ facturing processes. It is for these reasons that creative work involves more and more facets. Besides ergo­ nomic, functional and technical factors (the ABC of the product designer), it is becoming ever more necessary to convey emotions, and to recognise the needs of users, or often to guess these. Factors that lend the design fur­ ther roots and make products more l ivable, more differentiated in the market and even more accessible for the user are therefore gain­ ing in importance. And like advertisin g , this happens by playing with our senses. High-tech and high-touch

The start of every design process is marked by the agency briefing in which the customer describes the services required - besides technical aspects like size, functionality and target cost, also numerous "soft" factors. In addition, almost every brief includes a so­ called CMF (colour, material, finish) study plus details of the image of a brand. From healthy fruit drinks to medically efficient toothpaste. What does the brand stand for? "Trustworthy, reliable, innovative, special, technical, custom­ er-focused, leading" are just some of the terms often found in agency briefs. Which materials can be matched to these attributes? Which materials can be realised in an i ndustrial proc­ ess in the sense of production and costs? Med­ ical technology products save lives and must convey this fact (fig . A 6.2) . Mobile phones, on the other hand, have become fashion accesso­ ries, not least because of their short l ife cycles. It is therefore not unreasonable to assume that the choice of materials for these products will be very d ifferent. But subtleties such as surface characteristics and the exact coordination with the aesthetics in detail are also important. Materials like glass suggest a certain value over plastics - visually, but in particular in their everyday handling. The material can g ive a brand a good, d ifferent feel i n g . In t h e early creative phase, many different materials are tried out - touched, bent and glued - in order to find inspiration for new ideas (fig. A 6. 1 ) . Of course, a silk DVD player is pure fantasy; however, an unencumbered approach can help to adapt elements of various materials styl istically into the design language or into individual parts. Even in the development of software, analogies to the physical world are used to convey emotions and lend virtual products a visual-haptic experience. I n order to design the successful products of tomorrow, the designer needs not only a d is-

tinctive "gut feeling", but also a wider view. Pens and pencils, CAD software and comput­ ers are only tools; creativity comes from inside our heads. And that is where our eyes are, which must always remain open. When consid­ ering materials, the maxim is: What are the trends in manufacture? What is new in related disciplines like fashion, architecture or trends research? Which materials are currently under­ going development and which are sti l l niche p layers? A space shuttle can provide just as much inspiration as a fashion show in Milan. For example, the luxury suitcase "Henk" designed by the "frog design" agency is made from carbon fibre, a material borrowed from the cockpits of Formula One racing cars (fig. A 6.7) . The designer should focus on what these trends and developments mean for his or her projects, e . g . for a mobile phone manufacturer, a watchmaker or a customer from the lifestyle sector who is looking for completely new prod­ uct concepts and whose brand-name claims are to be expressed three-dimensionally in the future. The expressive manifesto i n the form of the right choice of material for a l ifestyle prod­ uct becomes more important as the price of the product climbs and so is aimed at a d ifferent market segment. Mass-produced products are primarily d istinguished through colour, but here too, there are dozens of nuances. Those work­ ing in niche or "high-end" markets use carefully chosen materials and their surface characteris­ tics to express their exclusivity. Sales of prod­ ucts made from materials with a high-quality appearance basically offer the chance of gen­ erating greater profit margins; at the same time, the target groups addressed have greater expectations regard ing quality, individuality and product benefits.

A 6.3

The differentiation trend

Globalised markets and hence an (over-) Iarge range of similar and interchangeable products lead to every d ifferentiation option being exploited. Driven by this fact, but also by a media world anxious to enlighten us, consum­ ers - perhaps more properly called "users" have in recent years become more knowledge­ able and more self-confident when it comes to personal selection and appraisement of pur­ chasing decisions. Advertising campaigns that tell us saving money is a worthwhile pursuit may represent a trend in the lower price seg­ ment in times of recession. However, the actual driving force in the tough battle for the hearts and money of the customers is the wish for these to buy products that correspond as pre­ cisely as possible with their desires. The much­ d iscussed "mass customisation" is stil l in its infancy, but does at least awaken the idea that customers can take part in the design process, e . g . when buying a car with a selection of com­ ponents. Modular product components for cer­ tain target groups, e . g . individually adjustable software user interfaces for mobile phones, prove, however, that this process is not taking

A 6.4

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Touching the senses - materials and haptics in the design process

A 6.5

A 6.6

place just to generate ind ividual artificial fea­ tures, but that the market demands this. The work of marketin g departments is therefore dominated by workshops in which the house brand is presented as an actor, as an automo­ tive brand, as a colour or as a material. Are Marlboro cigarettes really like the leather of a cowboy saddle? Associations are establ ished, help to l ift things out of a vacuum, at least in metaphors. Designers draw their conclusions and then create the haptic experience. One example of a successful and at the same time very obvious realisation is the holistic brand­ name and product image of the Orangina drink (fi g . A 6.4) . The shape of the bottle and the its surface are based on the citrus fruit itself - the drinking experience begins on the supermarket shelf. Automotive sector as vanguard

A 6.7 A 6.5

Apple mouse: high-quality plastic as interface between computer and user A 6.6 & A 6.8 Design study: a notebook designed to resemble a school exercise book to create an interactive learning experience for children. A 6.7 "Henk" trolley case: the carbon fibre material is extremely l ightweight but also extremely robust. A 6.9 Violin: understandably, the feel of a musical instrument plays a special role. A 6 . 1 0 Facade of ETFE film cushions, Allianz Arena, Munich, Germany, 2005, Herzog & de Meuron

A 6.8

34

The Greek philosopher Aristotle once described the sense of touch as an intrinsic element of human, cognitive ability. The disci­ p l i ne of product design is admittedly compara­ tively you n g , but haptics has always played a major role in form-finding - in the theoretical and practical senses to an equal extent. It is therefore rather surprising that this theme has only in recent years become fashionable in the sense of an ail-embracing customer experi­ ence. Like so often in the past, the automotive sector is now also playing a leading role in the haptics arena. The major car manufacturers have been operating their own haptics labora­ tories for a number of years, employing some of their best R&D engineers and searching for the next step towards the perfect and compre­ hensive customer experience. Volunteers are exposed to various stim u l i , touching, for exam­ ple, various dashboards while wearing goggles to cut out the visual experience completely. But seat coverings and steering wheels - in short all the articles to be found in the passenger compartment and with which the driver comes into contact - are also given this treatment. The results are recorded and evaluated by engi­ neers, psychologists and sociologists. Besides comfort, driving enjoyment and relia­ bility, the new magic phrase is "perceived qual-

ity". Today's car interior passes through the entire scientific procedure of assessing various surface materials and operating controls. Stud­ ies by Mercedes show that quality and the appearance of materials is primarily experi­ enced and evaluated by the sense of touch. Admittedly, the market leaders are not placing all their cards on the table. The competition is too fierce and the investment i n research too great to reveal all the competitive edges and technological advances. Touchlab

In the Touchlab at the world-famous Massachu­ setts Institute of Technology (MIT) , the subject is approached more theoretically. The official name of this research facil ity is the "Laboratory for Human and Machi ne Haptics", and it was founded in 1 990 by Or Mandayam A. Srinivas­ an. Here, the researchers get to grips with the principles of how people and machines inter­ act. The Touchlab investigates the human sense of touch and how it can be adapted for machines, new technologies or software, e . g . C A D tools for architects a n d designers. From the number of aspects to be investigated, the layman can only surmise the complexity of the research activities. Researchers from biome­ chanics, neuropsychology, motor skills and other scientific d isciplines work hand in hand. What drives the researchers? The d i g ital , virtu­ al, automated world places completely new demands on users through the growing com­ plexity of technical progress. The goal is to master this oversized funnel of stimuli and data - comparable with the challenge faced by pre­ historic man, who had to understand nature and learn how to master it. The findings of the Touchlab find their way into numerous new developments - in medical technology and robotics, video games and CAD software - and hence also into the design process and the work of industrial designers. The demands of users

In comparison with the development teams of the automotive industry or medical technology, designers know l ittle about the theme of hap­ tics - just enough for the successful outcome of a project from the client's point of view. But

Touching the senses - materials and haptics in the design process

A 6.9

placing the findings of science regard ing the sense of touch in the context of product bene­ fits, brand understand i n g and user requests is the prime task of the designer. In order to address the temptation to buy, besides the aesthetics - when, for example, we look at, touch and, of course, try out cameras, sports footwear, suitcases or MP3 players in the shops - it is the aspect of durability that plays a great role. Fli ppantly, we could say that our fingertips influence shopping trends. After the purchase, the relationship with the custom­ er enters a crucial phase: from the user's point of view, the actual product experience begins now. There are enough examples: constant use of a mobile telephone, the drive to the office with the steering wheel in our hands, or the computer mouse that keeps us in front of the computer for hours on end, linking us to the Internet and the software. The idea is always to keep the product and brand-name promises and to build up loyalty. Particularly in the case of everyday objects that we use frequently, carry around with us, become almost part of us, the recurring haptic experience is a key ele­ ment. Paints, switches, housings - these are all part of the haptic experience. But it is more than just touching these, it is also the emotional and intuitive feel of the interaction with the product. How does the user receive feedback when he or she enters a command into a mobile phone? When the spectacles case has been closed? The handling of products and

their participation in our everyday l ives turn functions into emotions and habits; products become our permanent companions. These examples demonstrate that the theme of "haptics" plays a key role, both i n the develop­ ment and design of a product and in its use by the customer. The successful interaction of haptics, aesthetics, materials, colourin g , prod­ uct q uality, also smell and sound , is elementary - just l i ke a good orchestra or a good meal and their individual constituents. Of apples and oranges and butterflies

Successful examples of an extremely trium­ phant combination of creativity, product claims and haptic experience are the products from Porsche and Apple. Supposedly, it is often the details that allow the user to recognise the spe­ cial dedication of the manufacturer. The mouse products from Apple are more expensive and of better qual ity than the products of most rivals. The creators of the iMac and iPod saw the mouse as the prime interface between user, software and hardware, in contact with the hand for several hours each day (fig . A 6.5) . Other manufacturers saw the computer mouse primarily as a piece of plastic and tried to save a few more cents in the production. Cars pre­ sent a similar picture: the Porsche designers and engineers regard every detail as an impor­ tant component in an overall statement of worldwide leadership in the development of sports cars. The fact that Apple and Porsche

are also very successful economically confirms the notion that it is worthwhile focusing on the desires of people, and that customers are also prepared to pay more when the extra benefits are relevant for them. Haptics is an important component in the design process, but not everything . This fact repre­ sents a compromise in the life of the designer, who leads a Jekyll-and-Hyde existence trying to balance art and commerce. The work of the architect is very simi lar in this respect: the draft design often simple and lucid, but the details almost always difficult, and the realisation con­ strained by pressure on costs, time and feasibility. The interaction of the senses is vital in our daily working and private lives. Touching a ripe orange, subsequently peeling it, smelling and finally eating this tropical fruit represent a holis­ tic experience. Eating is not only tasting, music is not only hearing, a sunset experienced amid nature is not only watching. I ndeed, there are many things we can learn from nature. Some species of butterfly can smell and taste with their legs. In a figurative sense, we can do that too.

A 6. 1 0

35

Part B Properties of building materials

Stone 2

Loam

3

Ceramic materials

4

Building materials with mineral binders

5

Bituminous materials

6

Wood and wood-based products

7

Metal

8

Glass

9

Synthetic materials

10

Life cycle assessments

Fig. Central iron-and-gl assItaldome, Galleria Vittorio Emmanuel e Mi l an, y , Giuseppe Megnoni B

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37

Stone

B

1 .1

Besides loam and wood, stone in its natural form was one of the first materials people used for building. In the early days of civilisation, everyday objects such as weapons, simple tools and jewellery were made from stone . Besides the pyramids of Egypt, t h e first struc­ tures built with natural stone worked into a more or less regular shape were the so-called megalithic monuments (from Greek: megas great + lithos stone ) , and the stone circles of Stonehenge in southern Eng land are probably the best-known examples (fig . B 1 . 1 ) . But even today we are still unsure as to how these huge blocks - up to 4 m high and weighing up to 50 tonnes - were transported from a quarry more than 200 km away and erected. It was in about 2700 BC that the oldest step pyramid made from coarsely dressed limestone blocks was built in Saqqara, Egypt. The man in charge of its construction, the vizier I mhotep, is regarded as the world's first architect. Various c u ltures and epochs have supplied us with their own specific forms of construction . The Greeks assembled stones without mortar joints to form architectural elements such as p l i nths, col­ umns, architraves and friezes. The Romans continued the development of vaultin g . By the 1 st century AD it was therefore possible to erect q u ite sophisticated infrastructure ele­ ments such as the 50 m high Pont du Gard aqueduct (fig . B 1 .2 ) . And in the Gothic era the stonemason 's art reached its zenith. The forces were concentrated in the net-like, delicate ribs of the vau lting and transferred to great p i l lars. The walls in between lost their load bearing function and were transformed into translucent, lightweight surfaces (fig . B 1 .5 ) . I n the 1 920s the use of very thin stone slabs as cladding became a feature of modern architecture. Adolf Loos ("Marble is the cheapest wallpaper") showed us the exclusively decorative use of c ladding made from Cipollino marble on the facade of his "Loos House" (fig . B 1 .6 ) . =

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BBB B B BB

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1.2 1 .3 1 .4

Stonehenge, near Salisbury,France, c.st century BC AD Pont du Gard, Provence, Dry stone walling, stone house near Gordes, France Padre lgrimagePianoChurch, Foggia, Apulia, IThe taly,resolPiouPitioRenzo n of mass - Gothic vaulting, Bath Abbey Church, "Loos uHouse", Vienna,madeAustrifroma, Dionysos Adolmarbl f Loose, Transl cent facade StFranz PiusFOeg Church, Meggen, Switzerland, UK,

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mass outside the layer of thermal insulation is now generally unnecessary and leads merely to more work on site and more fixings. The stone industry has responded to this: granite slabs 15 mm thick and sandwich panels with a 6 mm thick stone facing are now available on the market (see "The building envelope", p. 1 10) . In Berlin whole street fronts were clad with thin stone facings from all over the world with every conceivable surface treatment. I n recent years stone has enjoyed an unexpected renaissance. Without doubt also due to the fact that surfaces and sensual qualities have become more im­ portant again. The winery of Herzog & de Meuron in Califor­ nia, USA, as wel l as the thermal baths in Vals, Switzerland , by Peter Zumthor are wel l-known examples of how to use the specific surface qual ities of natural stone. Franz Fueg had already used the light-permeable properties of marble on his St Pi us Church in Meggen, Swit­ zerland, in 1 966. The sunlight transforms the smooth marble panels into illuminated, veil-like surfaces (fig . B 1 .7 ) . In his desig n for the Padre Pio Pilgrimage Church in Foggia, Italy, Renzo Piano devised a remarkable solution (fig. B 1 .4). Blocks of the local limestone were assembled to form prestressed arches spanning more than

Contemporary applications

I n our modern thermally insulated facades, stone has lost its structural function. The increased requirements placed on thermal i nsulation and the performance of the building envelope in Central Europe means that all

B

1 .3

Stone

50 m. To achieve the necessary tolerance of ±0.5 mm for each element, the experience of many generations of marble stonemasons from Carrara went into the working of the stone.

Properties

There is an impressive d iversity of natural stone. In Central Europe more than 500 varieties, worldwide about 5000, are offered by the trade. And as every type of stone exhibits specific properties and features, the potential applica­ tions are correspondingly diverse (fi g . B 1 . 1 0) . Petrography is the study of rocks. The usability of a stone is determined by its petrographical, i.e. mineralogical and chemical, features, plus a number of technical parameters.

behaviour, water absorption and resistance to chemicals. Good thermal conductivity is important when stone is used as a floor covering. Stone floors are often perceived as cold because they con­ duct heat away from the body. However, their heat storage capacity can be a great advan­ tage, also in conjunction with underfloor heating , Risks specific to the material

The following properties should be considered at an early stage of the planni n g :

. Petrographical properties: structure, chemistry, mineral content (colour, crystall ine structure and hardness) Technical parameters (fig . B 1 . 1 2) : density (true density, bulk density and porosi­ ty), strength (compressive, flexural and abra­ sion resistance), thermal conductivity, thermal expansion, heat resistance, freeze-thaw

Temperature: The thermal expansion l ies between 0.3 and 1 .25 mm/m (for a temperature d ifference of 1 00 K) depend ing on the type of stone. Suita­ ble joints and fixings are essential for the cladding to a facade. Water trapped in the pores and capillaries of the stone can cause damage when it freezes because its volume increases by about 9% as it turns to ice . Although the majority of i gneous rocks are classed as frost-resistant, numerous aspects must be sti l l taken into account if problems are to be avoided.

B 1.5

B 1.6

•

•

•

Chemical stability: Acids and airborne pollutants (e.g. S0 and 2 CO ) can cause considerable damage to 2 limestone and sandstone.

Effect and design

Stone stands for tradition. It is the embodiment of durab i l ity, authority and quality. Even when the modern stone facades of Central Europe are usual ly no more than a thin cladd ing, we sti l l associate stone with stability and strength , e . g . for banks. Every type of stone has its own character derived from its grain and porosity as well as its colour. The surface treatment, e . g . bush-hammerin g , polishing, sandblasting, can have a fu ndamental effect on the appearance of a stone surface (fig . B 1 . 1 3) . Although these days we can employ stone from the four cor­ ners of the Earth, stone was originally a region­ al material which created a clear reference to the locality (fi g . B 1 .3 ) . The streetscapes of, for example, London or Paris were always charac­ terised by a uniform, local stone.

B 1.7 39

Stone

Rock 1

I gneous

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1

Plutonic 11 Hypabyssal J 1 Extrusive 1

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Rock formation

According to our present state of knowledge, the planet Earth was formed about 4.5 b i l lion years ago by the agglomeration of interstellar material. After the transition from the gaseous to the molten state, the first coherent crust, the Earth's surface, formed at a temperature of about 1 00Q-1 500°C. Rocks are formed by the crystallisation of liquid magma. They consist of various minerals, primarily s i l i cates, held together by aggregation or a binder (e . g . clay) . Their genesis is a decisive feature enabling us to divide rocks into three main divisions: i gne­ ous, sedimentary and metamorphic.

Rock divisions

We must d istinguish between scientific and commercial nomenclature when classifying types of rock. Only when we know the petro­ graphic designation of the rock group and rock type is it possible to obtain a g uaranteed assessment of the properties and the potential applications (fig . B 1 .8) . Trade names are often arbitrary, and inaccurate designations such as

"Belgian granite" (actually l imestone) can re­ sult in considerable damage if the real nature of the rock is not known. Igneous rocks

These types of rock are formed d i rectly from liquid magma and are d ivided i nto three sub­ d ivisions according to their place of origin: Plutonic rocks Named after the god of the underworld, these rocks are formed by the full crystallisation of "mobilised magma" in the Earth's crust. The ­ usually - uniform, non-d irectional and dense structure is due to the gradual coo l i n g . The varying mineral composition gives rise to rock types l i ke granite, diorite and gabbro. Almost all plutonic rocks are frost-resistant and are popular in building owing to their high com­ pressive strength and hardwearing q ual ities. Some i gneous rocks, e . g . granite, can exhibit above-average natural rad ioactivity in some circumstances. Hypabyssal rocks These types of rock are formed when small amounts of magma solid ify within the Earth's crust in volcanic vents or fissures. Their struc­ ture is similar to the plutonic rocks but the faster cooling process results in non-uniform crystall isation with phenocrysts of other mate­ rial. This subdivision includes pegmatites, aplites and lamprophyres.

B

1 .8

Sedimentary rocks

Sediments are mainly formed by the weather­ ing, erosion and deposition of older rocks (igneous, sedimentary or metamorphic) which are then transported by water or glacial move­ ments and deposited again in the form of debris, gravel or sand. These rocks frequently contain animal or plant fossils. The pressure of the overlying strata compresses the individual particles of the sediments to form a solid mass, cemented together by water containing binders (e. g . quartz, calcite, clay) circulating in the remaining voids. This process of the solid ifica­ tion of sediments is known as diagenesis. Clas­ tic sediments consist of the mechanically disin­ tegrated parts of the orig inal rock. Depending on the grain size, we distinguish between con­ g lomerates (� 2 mm) , sandstones (0.02-2 mm) and siltstones (5,; 0.02 mm) . Chemical sedi­ ments are "precipitation" from solutions as a result of chemical reactions or biological proc­ esses which subsequently solidify under pres­ sure. These include limestone , shelly limestone and travertine. The properties of sedimentary rocks that are interesting for building purposes vary considerably and essentially depend on the conditions during their formation (tempera­ ture, pressure) and the respective binder. Chemical sediments (e.g. onyx, petrographic name: calc-sinter) are particularly suitable for internal finishings owing to their d iverse tex­ tures. Metamorphic rocks

Extrusive rocks I n contrast to plutonic rocks, rocks of this type, e.g. d iabase, basalt or rhyolite, form at the transition between the upper mantle (crust) and the surface of the Earth. The rela­ tively fast cooling process leaves these rocks with a fine crystalline structure. Partial melting of neighbouring rocks can lead to hig hly d iverse appearances.

B 40

1 .9

Metamorphic rocks are formed from existing rocks and are called orthorocks when formed from igneous rocks or pararocks when the orig­ inal material is a sedimentary rock. High pres­ sures, high temperatures or chemical influenc­ es transform the original rock or even form completely new types. They are usually easily recognised by their dense structure free from virtually all voids, their distinct texture or the clear bedding marks. Their chemical compos i-

Stone

tion, appearance and uses in building vary considerably. I mportant metamorphic rock types are slate, marble and gneiss.

Types of stone

A selection of the most common types o f stone used in building is g iven below. Granite

Granite is probably the best known of the plutonic rocks (fi g . B 1 . 1 1 a). Its constituents are feldspar (which determines the colour) , quartz (responsible for the high mineral hardness) and mica. Granite is weather-resistant, is regarded as the most resistant of rocks, can be used almost without restriction in building work, and is unaffected by airborne pollution. N umerous colours are available: red, pink, yellow, white, grey, blue-green. Basalt

Basalt is a dark, usually dark grey to black, extrusive rock with a dense, non-directional structure consisting mainly of feldspar and augite (fig . B 1 . 1 1 b ) . It exhibits a very high compressive strength, is extremely difficult to work, is weather-resistant, and is ideal for external applications. However, it can become very slippery when smooth. Weathered and aged basalt is also known as diabase. It is formed by the chemical disintegration of the mineral constituents (e . g . chlorite, serpentine) . Sandstone

Sandstone belongs to the group of clastic sedimentary rocks and consists primarily of quartz grains in the size 0.02-2 mm cemented together by a binder. Sandstones are found in many colours: red, yellow, brown, green (fi g . B 1 . 1 1 c) . The type of binder (q uartz, calcite, clay) determines primarily the strength, water absorption and frost resistance. Sandstone is regarded as easy to work and is found on many older buildings. However, owing to its low abrasion resistance it is not suitable for heavily trafficked floors.

a

b

Limestone

This is a chemical sedimentary rock that was formed during various geological periods, originally in water - proved by the fossils found in limestone. It consists mainly of calcium carbonate and occurs in various colours, usually yellowish, grey-brown, red or white (fi g . B 1 . 1 1 d) . Limestone can be used almost universally. Only its use in areas that req u i re frequent cleaning (e. g . entrances, public buildings) or wet areas is not recommended owing to its low resistance to the chemicals used in cleaning agents. Its abrasion resistance d iffers considerably depending on the particular rock deposit.

•

o

suitable suilesstable

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Igneous rocks

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Granite Syenite Diorite Gabbro Rhyolite (porphyry) Trachyte Basalt Diabase Braccia Conglomerate Sandstone Calcereous sandstone Greywacke Volcanic tufts Limestone Shelly limestone Solnhofen limestone Dolomite Tuftaceous limestone Travertine Orthogneiss Serpentinite Migmatite Paragneiss Quartzite Mica-schist Clayey shale Marble B c cl a ssi f i c ati o n of rock types BB Systemati Art gal, Henni lery, Wurth, Schwabisch Hall, Germany, n g Larsen B Appl iceationloyns) for various types of stone in building gui d ( scoarse-grai of commonntypes of tstone B Exampl Eginefgenstei ed grani e ab Grei n er basal t sandstone cd Seeberger Jura l i m estone Moselte lTogo e slatemarble fe Whi ·

·

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Sedimentary rocks

Marble

Marble, a pararock, is formed by the metamorphosis of calcareous sed imentary rocks. Pure marble is white, crystalline and free from fossils. The crystal surfaces shine in bright l i g ht (fig . B 1 . 1 1 e) . This stone is ideal for scul pted work with fine contours, but is also used in b u i l d i ng as a floor finish or wall/facade cladd i ngo

·

·

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Clayey shale

The term shale designates the spl itting or cleaving properties of rocks, with the m ineral i nclusions (clay, chlorite, mica) indicating the degree of metamorphosis. Clayey shale exh i bits a sheet-like, parallel structure. It is a very fine-grained, dense stone and usually dark grey to black in colour (fi g . B 1 . 1 1 f) . Its good cleaving ability enables the production of thin slabs just 5-7 mm thick. Owing to the shaley structure, its strength depends on d i rection. Shales in the form of slates have been used for centuries as roof coverings, cladding and floor tiles.

·

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Metamorphic rocks

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Building with stone

Stone is usually obtained from open q uarries, with only some types of marble, slate and limestone being obtained from underground mines. When exploring new sources, the extent of the deposit and the properties of the stone are estimated by way of ultrasound measurements, or samples are obtained from deep boreholes.

c

1 .9

2001

1 .1 0 1 .1 1

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1 .1 1

41

Stone

Hydraulic wedges are driven between the blocks along natural cleavage p lanes in order to separate the blocks. Diamond-beaded steel wires and cross-cutters (sort of oversized chainsaws!) have also become common in re­ cent years. The aim of q uarrying is to obtain approximately right-angled blocks of a suitable size and in doing so to generate as l ittle "waste" as possible. Quarrying i nvolves de­ struction of the landscape, and creates large quantities of d ust and debris. New deposits may therefore only be q uarried when certain of­ ficial stipulations are met. Those stipulations i n­ clude restoration of the landscape once the workable deposits have been exhausted. Industrial processing

Cleaving of the stone is usually carried out d i rectly in the quarry especially in the case of paving stones and stone for ashlar wal l i n g . Otherwise, the stone is transported t o factories for further processing - it is then that we speak of dressed stone. The use of reg ional deposits and hence short d istances between quarry and works considerably improves the life cycle assessment for natural stone. Various methods are used to process the quar­ ried blocks:

example, floor coverings in public buildings must comply with non-slip grade R 9. Henning Larsen developed and used an unusu­ al technique on the facade cladding to the art gal lery in Wurth, Germany. The Crailsheimer shelly l imestone he used was cut perpendicular to the cleaving p lane (fig . B 1 .9).

•

•

Steel-shot abrasion or diamond saws: for 20-80 mm thick slabs (the time taken to saw through a 1 .20 m high block of granite is about 1 -2 days) Taglia Blocci saws: for stone tiles or long strips with a thickness of about 1 5 mm Gangsaws with circular blades or steel wires: for the production of coarse slabs > 80 mm thick; steel wires can also create three-dimen­ sional workpieces.

Surface finishes

We distinguish between stonemason tech­ niques and industrial processi n g , although new compressed-air tools are enabling "manual" methods to gain popularity again (fig . B 1 . 1 3) . The type of surface finish satisfies both aesthet­ ic criteria and functional requirements. For

(guide only) B 1 . 1 3 Various manual and machine-applied surface finishes: a

Limestone, coarse-pointed: The surface is broken away using a hammer and a pointed chisel (pyramidal form), with the depth and angle of cut determining the grade of finish (coarse or fine). The entire sur­ face is worked in this way.

Applications

b Limestone, pointed and ground:

Stone in the form of aggregates for concrete and mortar or for producing mineral binders accounts for the largest share of natural stone in build i n g . I n order to establish the suitability of a type of stone for building work, the stone i ndustry classifies stones as hard ( i g neous and some metamorphic rocks) or soft (sedimentary rocks ) . However, owin g to the availabil ity of rel­ atively "soft" i gneous rocks and very hard sedi­ mentary rocks, the specific physical properties (compressive strength, frost resistance, abra­ sion resistance) should always be checked for the application when choosing a type of stone (fig . B 1 . 1 2) . Generally, stone is suitable for the following applications in b u i l d i n g : · · · ·

•

B 1 . 1 2 Physical properties of various types of stone

• ·

Grinding the whole surface reduces the powerful texture of the first treatment. c Limestone, comb-chiselled: Varying blows and d ifferent chisel widths can be used to achieve d ifferent effects. d Limestone, bush-hammered: Fine to coarse, even surfaces can be pro­ duced with a bush hammer. The spacing of the pyramid-shaped teeth varies between 4 and

15

mm depending on the type of

hammerhead. e

Limestone, bush-hammered, brushed and ground: The superimposition of the three operations gives a finer, smoother finish to the initially coarse texture. Limestone, diamond-sawn: Diamond-tipped saw-blades create a relative­ ly fine cut surface and leave behind traces of the sawing process.

masonry gabion walls facade cladding floor finishes internal linings roof coverings

g Granite, bush-hammered: Bush-hammered granite finish achieved with a machine. h

Granite, fine-pitched: The rough-split surface is worked with a

30

mm wide chisel. This vigorous finish is

achieved by changing the d irection and depth of the chiselling. i

Disposal

Granite, flamed: Extremely high temperatures from a torch

Natural stone can be fully reused within the total product l ifecycle of quarrying, processing and disposal. Even so-cal led waste products that are generated during processing can still be used as aggregates. The disposal of stone in landfil l sites for building debris does not cause any problems, and it is generally possi ble to reuse slabs and panels . The Forum Romanum is an excellent example of this - during the Renaissance it was the largest source of used natural stone!

destroy the surface structure of a crystalline stone. Only rock types containing quartz are suitable for this type of surface treatment, and the slab must also be sufficiently thick. Granite, sandblasted: Sandblasting is suitable for creating coarse surface finishes, which vary depending on the blasting media used and its exit velocity. k

Granite, ground: The colour and texture of a stone becomes clearly visible on finely ground surfaces. Any grit size can be chosen between (coarse) and

C

500 (fine).

Polishing can be regarded as very fine grind­ ing in which a polishing medium is used to give the surface such a high sheen that it reflects the light.

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42

b

30

Granite, polished:

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Stone

Abrasion resistance

Water absorption

[cm'/50 cm"]

[% by mass]

Coefficient of thermal expansion [mm / mK]

Vapour diff. resistance index '

[W/ mK]

Heat storage index 2 [kJ / m'K]

1 30 -270

2.8 ( 1 .6-3.4)

2370-2550

0.008

1 0 000

5-8

1 60 -240

3.5

0.008

1 0 000

5-8

0.2-0.9

2800-3000

1 70 - 300

3.5

0.0088

1 0 000

5-8

0.2-0.4

Gabbro

2800-3000

1 70 - 300

3.5

0.0088

1 0 000

5-8

0.2-0.4

Rhyolite (porphyry)

2500-2800

1 80 - 300

3.5

0.0125

1 0 000

5-8

0.2-0.7

Trachyte

2500-2800

1 80 - 300

3.5

0.01

1 0 000

5-8

0.2-0.7

Basalt

2900- 3000

240-400

3.5 ( 1 .2-2.0)

0.009

1 0 000

5-8

0 . 1 -0.3

Diabase

2800-2900

1 80 -250

3.5

n.a.

1 0 000

5-8

0 . 1 -0.4

Density

Compressive strength

Thermal conductivity 1

[kg/ m']

[N/ mm"]

Granite

2600-2800

Syenite

2600-2800

Diorite

Type of rock

H

Frost resistance

Igneous rocks

2640-2730

0 . 1 -0.9

Sedimentary rocks 0.5- 1 . 0

0

Braccia

2600-2750

50- 1 60

2.3

n.a.

2/250

Conglomerate

2200-2500

20- 1 60

2.3 ( 1 .2- 3.4)

n.a.

2/250

1 4-80 '

0.8-1 0

Sandstone

2000-2700

30 - 1 50

2.3 ( 1 .2-3.4)

1 760-2380

0.012

2/250

9-35

0.2-1 0

0

Quartz sandstone

2600-2700

120-200

2.3 (2 1 )

2290 -2380

n.a.

30/40

7-8

0.2-0.5

0

Greywacke

2600-2650

1 50 - 300

2.3

n.a.

2/250

7-8

0.2-0.5

Volcanic tuffs

1 800-2000

20-30

2.3 (0.4-1 .7)

0.004-0.01

1 5/20

1 0-35

Limestone

2600-2900

75-240

2.3 (2.0-3.4)

0.0075

200/250

1 5-40

0 . 1 -3

0

Shelly limestone

2600-2900

80- 1 80

2.3 (2.0-3.4)

0.003-0.006

2/250

1 5-40

0.2-0.6

0

Solnhofen platy limestone

2500-2700

1 80 -260

2.3

0.0048

200/250

15

0.2-0.6

6-- 1 5

Dolomite

2600-2900

75-240

2.3

0.0075

200/250

1 5-40

0 . 1 -3

Travertine

2400 -2500

20-60

2.3

0 . 0068

200/250

20-45

2-5

Tuffaceous limestone

1 700 -2200

30-50

0.85-1 . 7

0.003-0.007

20/200

n.a.

1-10

0

0 0 0

Metamorphic rocks 2370-2730

Orthogneiss

2600- 3000

1 00 -200

3.5 ( 1 .6-2. 1 )

Serpentinite

2600-2800

1 40 -250

3.5 (3.4)

Migmatite

2600- 3000

1 00-200

3.5 ( 1 .6-2.6)

2370-2730 2370-2730

0 .005-0.008

1 0 000

4-1 0

0 . 005-0.01

1 0 000

8-1 8

0.3-2. 0

0 .005-0.008

1 0 000

4-1 0

0.3-0.4

0.3-0.4

Paragneiss

2600- 3000

1 00-200

3.5 ( 1 .6-2. 1 )

0 . 005-0.008

1 0 000

4-10

0.3-0.4

Quartzite

2600-2700

1 50-300

3.5

0.D125

1 0 000

7-8

0.2-0.5

Mica·schist

2600-2800

1 40-200

2.2

n.a.

800/1 000

1 5-25

0.2-0. 4

Clayey shale

2700-2800

50-80

2.2 ( 1 .2-2. 1 )

2430-2520

n.a.

800/1 000

n.a.

0.5-0.6

Marble

2600-2900

75-240

3.5 (2.0-2.6)

2370-2640

0.003-0.006

1 0 000

1 5-40

0. 1 -3

1

0

0

Values according to general information on thermal conductivity in EN 12524 and D I N V 4 1 08·4; values in brackets taken from trade publications.

2 The specific heat capacity of stone is specified as 1 kJ/kgK in EN 12524; in the absence of values, the heat storage index corresponds to the density.

, Values according to EN 12524 and D I N V 4 1 08-4. , Composite rock - the abrasion resistance therefore fluctuates considerably. B 1 . 12

9

h

k

B 1 .1 3

43

Loam

B 2.1

B 2.1

Studio 400 Rubio Avenue, Tucsonl Arizona (USA)

B 2.2

Trian9ular network for loam designations

B 2.3

Mean drying shrinkage of loams for building

B 2.4 B 2.5

Shrinkage cracks due to drying out Exhibit in the Art Gallery in Bregenz, Austria, 2001 ,

B 2.6

Loam-rendered house, Barna, India

1 998, Rick Joy

Olafur Eliasson B 2.7

Loam wall around the rock garden of the Ryoanji Temple, Kyoto, Japan, late 15th century

44

The early civilisations developed in the large river valleys of our planet, where clay and loam were readily available as bui lding materials. Those early cultures that have been researched most thoroughly are those centred around the N i le in Egypt and Mesopotamia. Some 5000 years ago, these were the locations of the first settlements b u i lt from loam. Even the G reat Wall of China, the largest man­ made object on this planet, is to a large extent made from tamped loam. Only later was it g iven a facing of bricks and stone, and thus turned i nto a "masonry wal l " . I n Europe too, bui lding with loam has a long tradition. The real heyday was during the early decades of our modern industrial age because as forests were cleared, suppl ies of timber decl i ned and became expensive, which encouraged the spread of building with loam . In the towns and cities loam was primarily used for the infill panels of timber-framed buildings, or as a form of rendering. I n Wei l burg an der Lahn in central Germany, five-storey houses up to 20 m tal l were b u i lt from tamped loam, and those houses are sti l l occupied today. Howev­ er, a distinctive architectural style never emerged for this material. Loam was regarded as the building material of the poor, was mainly hidden behi nd rendered facades and gradually lost much of its significance as the brickmaking industry became established towards the end of the 1 9th century. After the two world wars, when bui lding materi­ als, energy and money were hardly plentiful commodities, people turned to loam once again. The German loam bui lding code became D I N 1 8951 in 1 95 1 , but was withdrawn and not replaced durin g the years of the "Eco­ nomic Miracle" . It was not until the oil crisis and the emerg ing environmental movements of the 1 970s that interest once again turned to loam as a building material. Loam building today

Even today, one-third of the world's population lives in loam houses, and in the countries of the Third World this figure rises to more than half. The reasons for using loam vary across the world. In poorer regions loam represents a locally available, affordable building material

for which there is hardly any equivalent substi­ tute. In Central Europe on the other hand, the rediscovery of loam as a building material is due primarily to the desire for a good interior c l imate, living accommodation free from haz­ ardous substances, and architectural aspects. The transition from the traditional to the con­ temporary loam building culture has called for fundamental innovations in terms of product development and the integration of this material into our modern methods of bui lding . Building with loam is currently one of the growing mar­ ket segments in the building industry. This trend is reflected in the number of projects complet­ ed and a gradual increase in the number of prefabricated loam products, which are prima­ rily used for non-load bearing components. In Germany, the old standards were updated and supplemented in 1 999, and republished in the form of a new "Loam Building Code". This code has now been incorporated into the build­ ing codes of the majority of Germany's federal states, making loam bui lding one of the acknowledged construction methods of the modern age.

Properties

Mass, good mouldabil ity, robustness and excellent adhesive and bonding forces count as the main properties of loam. Diverse addi­ tions (e. g . whey, soda) plus organic or mineral aggregates are suitable for optimising the building material q ualities according to the type of application. Loam is odourless, non-toxic and pleasant to work with. Like virtual ly no other building material, loam fulfils the criteria of sustainable and resources­ sparing construction. It is available in almost all regions of the world. Energy for transport can be saved by using excavated material. The building of a solid tamped loam wall req u i res only a fraction of the primary energy of a comparable wall made from concrete or clay bricks (see "Life cycle assessments", page 1 00). Loam can be reused an i nfinite number of times and returned to the natural product l ifecy­ cle without causing any problems. Its good

Loam

'l?

c2

�

Clay

Designation according to cohesion

6Q Clay, sandy

Sandy, ' v clayey loam

and

Sandy loam

Clay, sillY Ciayei' loam Loam

Silly loam

lean loams

1 .0-2 .5 %

medium loams

2.0-3.5 %

fatty loams

3.5-5.5 %

clays

4.5-7.5 %

B 2.2

heat storage capacity can help even out tem­ perature fluctuations, The interior c l imate is also improved by the material's abil ity to absorb water vapour and release it again as requ i red, a property known as sorption capacity. The sorp­ tion capacity of loam plasters is 1 .5 to 3 times that of conventional plasters. The diversity of loam deposits and the associat­ ed considerable differences in their composition call for experience in the assessment of this material for building applications. Without addi­ tives, loam is very sensitive to water. As it becomes wetter, so it loses its strength, and therefore surfaces exposed to the weather must be protected against erosion (fi g . B 2.4) . Shrink­ age cracks can sometimes appear as the mate­ rial dries out, which in the wet loam method can amount to 3-1 2%, but in the tamped loam meth­ od less than 0.5%. Compared to other building materials, loam has a low strength (similar to that of lean concrete), but this is ful ly adequate for the majority of building tasks.

B 2.3

Loam for building

Loam essentially consists of clay, sand and silt (ultra-fine sand). However, it can also include larger grains (e. g . g ravel ) and organic constitu­ ents. Depending on the main component, we speak of clayey, silty, or sandy loam (fi g . B 2 . 2 ) . The clay acts a s a binder which bonds together the other sand, silt and gravel "fi l lers".

B 2 .4

Origins

Clay is a product of the weatherin g (degrada­ tion) of rock, whose raw material is generally m inerals such as feldspars. The rock is subject to mechanical and chemical reactions, which transform it. The properties (fig . B 2 .3) and des­ i gnations of the loam vary depending on the location of the deposit: •

•

•

•

Surface finish

We distinguish between architecture employing a decorative loam render and non-rendered , tamped loam structures (pise - rammed earth) . In Japan the masters of loam building have developed their art to such an extent that you can see your reflection in the walls! Some of these loam render surfaces are protected by preservation orders; likewise coloured surfaces, which enjoy particular esteem as a sign of their age (fig. B 2.7). At the same time, contemporary architecture in Europe and the USA has rediscovered the qual­ ity of raw, untreated surfaces (figs B 2 . 1 and B 2.9) .

Mean drying shrinkage

•

Mountainside loam: In geological terms this type of loam is rela­ tively young and is deposited on the rocks from which it originates. Its granulometric composition makes it ideal for components requiring a good compressive strength . Boulder loam: Glacial movements deposit this loam. Its rounded grains and lower clay content g ive it a reduced tensile and compressive strength . Marl: Marl is a boulder loam containing l ime. Alluvial loam: This is boulder loam that has been redeposit­ ed by water. Most of the lime has been removed to leave a material that is readily usable for building purposes. Loess loam: Loess has a very finely-grained m ineral struc­ ture and often a low clay content. It is easier to use than fatty loams. However, its h i g her sensitivity to water calls for special care dur­ ing construction.

Extraction

If the excavated loam is used d i rectly for build­ i n g , it must be obtained from an adequate depth free from roots and humus. It is also pos­ si ble to obtain loam from excavations for the brickmaking industry. Owin g to the hig hly d iverse properties and compositions of loam deposits, the material's suitability for the respective application must be checked. Besides laboratory tests, there are also simple methods ( D I N 4022-1 ) that can serve to provide an initial indication of the loam's properties. Such methods are adequate for low-grade applications, e . g . i nfill panels, loose fill or mortar. It is not usually necessary to check material that has been mil led after exca­ vation or material that is supplied dry in sacks. B 2.7

45

Loam

Loam building materials

Not moulded

Timber light­ weight loam Straw light­ weight loam Mineral light­ weight loam

Moulded

Loam fill Lightweight loam fill

Loam board

Loam masonry mortar

Lightweight

Lightweight

loam board)

loam masonry mortar Loam plaster

Lightweight loam brick

Solid brick

Dry partitioning board

Perforated brick

mix Lightweight loam plaster mix Loam mortar for spraying

B 2.8

Systematic classification of loam building materials

B 2.9

Chapel of Reconciliation, Berlin, Germany, 2000, Reitermann + Sassenroth

B 2 . 1 0 Typical applications for loam building materials a Loam render b Tamped loam with mortar strips c Tamped loam with clay brick strips d Lightweight straw loam in moist condition e Loam inner lining i n timber-framed construction: unburned bricks, cladding of loam building board, loam plaster f Prefabricated timber-framed construction with lightweight loam brick infill B 2 . 1 1 Physical properties of loam building materials

Preparation

Depending on the properties and intended use of the loam , various options are available to improve the materia l 's properties. These incl ude soakin g , crushing, mixing, sieving, souring (storing the moist loam to i ncrease the bonding force of the clay), suspend ing in a slurry and making leaner (mixing with aggre­ gates to reduce the proportion of clay) . The add ition of organic (e. g . straw, casein, cellu­ lose fibres) or mineral (e. g . l ime, expanded clay) additives optimises properties such as strength, shrinkage and thermal insulation. I n America a n d Australia cement o r synthetic d is­ persions are often added to low-strength or water-soluble loam materials. However, this treatment impairs the material 's positive char­ acteristics such as sorption, d iffusion and recyclability. Based on the type and quantity of aggregates, we d isting uish loams for building accord ing to the density of the finished, dry components: • · •

solid and heavyweight loam (1 700-2200 kg/m3) straw loam ( 1 200-1 700 kg / m3 ) l i ghtweight loam (400-1 200 kg / m 3)

Loams for building

The desi gnation of loam building materials depends on the density, aggregates, process­ ing or type of use (fi g . B 2.8). During construc­ tion it is important to make sure that the respective building material - depending on wall thickness, temperature and humidity - is able to dry out for a period of 3-1 0 weeks. Tamped loam With a density of 1 700-2200 kg/m 3 , this is the heaviest type of loam and can be used for loadbearing walls. Such walls are constructed by placing the earth-damp loam in the form­ work in layers 1 00-1 50 mm thick and then compacting this. This layering can be seen later on the finished surface and creates the

46

B 2.8

specific texture of this material (figs B 2 . 1 0 b and c). Common wall thicknesses for load bearing walls are 400-600 mm. Infillloam This type of loam is used exclusively for the refurbishment of historical buildings. The semi­ stiff mix of straw and loam is placed in layers using hayforks. Sharpened spades are then used to strike off the excess material and this results in relatively flat wall surfaces. Straw loam Straw loam is a soft to pulpy prepared mix of loam and vegetable fibres (usually straw) that can be used for filling the panels in timber­ framed buildings or - pressed in moulds - for making loam bricks and boards (fi g . B 2 . 1 0 d) . Ready-made mixes are now available on the market. Lightweight loam Depending on the aggregates, we distinguish between organic and mineral lightweight loam. This material is suitable for walls, facings or the infill panels to floors, but cannot carry any loads apart from its own weight. It is placed moist in formwork or moulded into bricks and boards. Loose fill Organic or m ineral aggregates are mixed with earth-damp building loam to produce a loose fill material . The density varies between 400 and 2200 kg / m3 depending on the require­ ments. This material is usually used as a solid infill to floors and voids. Loam mortar for render, plaster or masonry All the major manufacturers now offer loam mortar, to which pigments can be added to achieve a wide range of colours (fig . B 2 . 1 O a) . I n contrast t o other types o f mortar, loam mortar

Loam

b

a

does not set. The working time can be pro­ longed indefinitely simply by adding water. Fi bre reinforcement can be added to mortar for render and plaster in order to prevent cracks in the finished surface. Bricks Many brickmaking plants produce loam bricks and unburned (sun-dried) bricks in addition to their standard range of clay products. •

Loam and lightweight loam bricks: These bricks are suitable for wal l infill panels

Loam building material

•

and facings, and floor toppings (fi gs 2 . 1 O e and f) . Provided the strength i s adequate, they can also assume a load bearing role. Earth-damp pressed bricks (compressed blocks) represent the most common form of loam building material in the world today. These are hig hly compressed, selected bricks from brickmaking production that were i ntended for firing but are then used without firi n g . Their high clay content gives them a good sorption capacity. They are used only for non-load bearing purposes and in unex­ posed areas not at risk of frost damage.

Compressive Thermal conductivity strength 1 [N/mm"l [W/mK]

Density [kg/m"]

2

B 2. 1 0

e

d

c

Boards Loam building boards are panel-type loam materials < 50 mm thick. They are used to con­ struct non-load bearing partitions. New prod­ ucts made from reed-reinforced lig htweight loam are also used for cladding dry partition­ i n g . Their flat surface is ideal as a background for loam plaster.

Heat storage index [kJ/m3K]

Vapour diffusion resistance index [-]

11

Building materials class 3

Type of loam A1

Tamped loam

1 700-2200

2-6

0.8-1 .4

1 700-2200

9/1 2

Loam infill

1 500-1800

2.5-3

0.65-0.9

1 500-1 800

8/1 0

not classified (nb)

Straw loam

1 200-1 700

2-3

0.5-0.8

1 200-1 700

8/ 1 0

not classified (nb)

400-1 200

s:4 '

0 . 1 2-0.5

3/5 (5/ 1 0)5

not classified (ne-se)

1 200-2200

2-4

0.5-1 .4

5/10

A1

600-1 200

n.a.

0 . 1 7-0.5

Unburned loam bricks, solid

1 900-2000

2-4

1 .05-1 .2

Unburned loam bricks, perforated

1 400-1600

n.a.

Loam boards

1 200-1 800

n.a.

400-1 200

n.a.

0 . 1 2-0.5

1 200-1800

n.a.

0.5-0.9

800-1 200

n.a.

0.25-0.5

1 200-1800

n.a.

0.5-0.9

600-1 200

n.a.

0 . 1 7-0.5

Lightweight loam

480-1 440 (400-1 200) 5

Products Loam bricks Lightweight loam bricks

Lightweight loam boards Loam masonry mortar Lightweight loam masonry mortar Loam plaster mix Lightweight loam plaster mix

1 200-2200

3/5 (5/ 1 0) 5

not classified (se)

1 900-2000

5/10

A1

1 .05-1 . 2

1 400-1 600

5/10

A1

0.5-0.9

1 200-1800

5/10

not classified (se-nb)

3/5 (5/1 0)5

not classified (ne-se)

5/10

not classified (se-nb)

3/5 (5/ 1 0) 5

not classified (se)

5/10

not classified (se-nb)

3/5 (5/ 1 0) 5

not classified (se)

660-1 200 (600-1 200) 5

480-1 440 (400-1 200) 5 1 200-1800 880-1 200 (800-1 200) 5 1 200-1800 660-1 200 (600-1 200) 5

1 The compressive strength must be determined in a test specific to the material; the permissible compressive stresses according to D I N are 0.3-0.5 N/mm2.

2 Figures according to Dachverband Lehm e.v. (a loam industry trade association); more favourable values must be verified according to D I N 5261 1 or 526 1 2 . 3 The building materials class must b e determined i n a specific test. T h e figures in brackets were supplied b y Dachverband Lehm e. V. and are intended a s a guide (ne

=

inflammable; se

= not readily flammable;

nb

=

incombustible).

4 Heavily dependent on type of aggregate; lightweight loam with mineral aggregate exhibits the highest strength; timber chippings

result i n a strength roughly twice that of straw.

5 Figures for loam with organic aggregates; values in brackets apply to loam with inorganic aggregates.

B 2. 1 1

47

Ceramic materials

B3.1 The name of this man-made material is derived from the Greek word keramos ( fired earth). I n itial ly, ceramic vessels were produced for storing foodstuffs and for relig ious purposes. The first tiles for walls and floors were probably the result of using fragments from broken ves­ sels. As early as 4000 BC, the early civilisations of Egypt, Mesopotamia and I ndia used fired clay bricks for constructing masonry. Their water resistance gave them a better durability than that of un burned (sun-dried) loam bricks. Build­ ers used the high compressive strength of the clay bricks to span vaulting over interior spaces and to construct domes. The roofs often includ­ ed terraces that were rendered waterproof with a combination of clay bricks and natural asphalt. The high compressive strength and abrasion resistance, durabi l ity and water resistance of ceramic materials coupled with the mouldability of the plastic clay mass prior to firing offer a wide range of possi b i l ities. I n the early days the spread of knowledge about the production and uses of fired clay bricks travelled the trade routes or was fostered through battle campaigns. The basis for production was always deposits of clay and brickworks in order to cover the rapidly growing demand of those early times. The development of various brick formats and masonry bonds provided an answer to construction and design issues. Clay roof tiles were first used in Greece in 800 BC, and since then have been used wherever it is necessary to construct and cover a pitched =

B 3.1

Hofhaus Estate. Fredensborg. Denmark. 1 963. J0rn Utzon

B 3.2

Julio Herrera & Obes warehouse

B 3.3

Use of recycled clay bricks.

Uru9uay. 1 979. Eladio Dieste business start-up centre. Hamm. Germany. 1 998. Hegger Hegger Schleiff B 3.4

Technical administration building. Hoechst dyeworks. Frankfurt am Main. Germany. 1 924. Peter Behrens

B 3.5

Clay bricks and mortar joints in various colours with d ifferent joint forms as well

48

roof surface in order to drain large quantities of rainwater. The original meaning of tegula, the Latin word for roof tile, is still used for the clay under-tiles used in some regions. Much of the masonry of Roman structures com­ prises two facings of clay bricks with a filling of trass. gravel and stones (opus caementitium) in between . The outer surfaces were finished with render or stone facings. The downfall of the Roman Empire also resulted in the loss of knowledge about building techniques. It was not until the Midd le Ages that the Gothic brick­ work of loam-rich northern Germany called for the rediscovery of the knowledge surrounding building with clay bricks. During the 1 9th century the number of clay bricks in use exploded. The invention of the extruder and the use of circular kilns resulted in industrial production with efficient use of ener­ gy, low waste and high-quality products.

Raw materials

The main constituents of clay are hydrous alu­ minium silicate compounds such as kaolinite and montmorillonite. These are created by the mineral re-formation during the erosion of rocks containing feldspars (e.g. granite. porphyry) . Added to this are impurities in the form of quartz, calcite. mica and iron oxides from the orig inal rock, plus organic residues. The two­ d imensional crystal s of the clay minerals exhibit

Ceramic materials

a foliar structure, which owing to its large sur­ face area is capable of storing capillary water and swelling. Hence, the clay minerals bond the aggregation and make the mass plastically mouldable. Non-shrinking grog in the form of sand, q uartz dust, clay brick dust, industrial waste (slag, ash) or organic substances (sawdust) guaran­ tee the post-drying and post-firing dimensional stability of products made from raw materials with a high clay content (fat clay) . The inherent colour of a ceramic material depends on the metal oxides of the constituent clay and the oxygen supply during firi n g . I ron oxide gives the body (i.e. the clay product with­ out the glaze) the well-known red colour, at higher temperatures a blue-green colour. Manganese in the clay leads to a body with a brown colour, graphite a grey body, and lime a yellow body. Pure clay (kaolin) is white (fig. B 3.5). The potential uses of the raw material depend on the composition of the natural clay deposit. Clay is obtained layer by layer from open-cast operations.

Ceramic materials for building

Owing to the different methods of preparing the raw materials, ceramic materials for building are divided into ordinary and fine ceramics according to the g rain, crystal and pore sizes of the fired body (fig . B 3.6) . Their properties such as strength, density, poro­ sity and water absorption are directly related to the firing temperature, firing time and material composition. As the firing temperature governs, we can classify ceramic building materials as follows: Clayware Stoneware, earthenware, hard-burned products Porcelain (kaolin) Refractory products Oxidised ceramics Special ceramics

900-1 000°C 1 1 00-1 300°C 1 300-1 450°C 1 300-1 800°C 1 500-2 1 00°C up to 2500°C

Manufacture

The preparation of the raw materials is carried out by means of milling, mixi n g , wetting or draining and subsequent storage in soaking pits to decompose the organic constituents. Moulding Plastic and partly powder-type masses are pressed into shape by industrial extruders. Interchangeable d ies determi ne the shape of the cross-section and wires cut the endless rib­ bon of material into predetermined lengths. Floor and wall tiles as well as more complex forms such as i nterlocking roof tiles are pro­ duced in presses.

Orying and firing The following processes take place during the heating of the moulded clay mass: At 1 20°C the unbonded water molecules, which are necessary for the mou lding, are removed as the material dries out. The firing process in the tunnel kiln begins between 450 and 600°C. At this temperature the physically bonded water and water of crys­ tallisation are removed. At 800°C the material solidifies and boundary surface reactions beg i n . Between 1 000 and 1 500°C individual phases melt and compact the mass. Above 1 200°C we speak of sinteri n g . The resulting vitreous struc­ ture surrounds the unmelted crystals and pores, which gives the sintered body its low water absorption. Surface finish The coloured, ceramic coatin g of clay slurry mixed with metal oxides, which is appl ied to roof tiles, facing bricks and wall panels by immersion or spraying prior to firi n g , is known as engobe. Besides giving the product its colour, at firing temperatures of 1 200°C and higher a sintered engobe finish results in a denser surface. Glazes are vitreous coatings which seal the ceramic material and determ i ne the hardness, smoothness and colour of the surface. The glazing mass comprises feldspar, quartz, lime and dolomite, plus metal oxides to provide the colour. The mass is fired and finely milled before mixing with water to form a slurry. It can be appl ied to the dried product before firing or applied to the fired product, which is then fired for a second time. Recycling

The recycling of clay bricks can prove to be a laborious process owing to the unavoidable mortar, render and plaster residue that tends to adhere to the bricks, particularly when such products have a high cement content. How­ ever, older masonry is easier to recycle because much of it was constructed using l ime mortar. The use of recycled clay bricks should be wel­ comed because this saves the high primary energy requirement necessary for producing new clay bricks and also exploits the good durabi l ity of the material (fig . B 3.3). Clay bricks can be used as loose fill or backfill material in civil engineering works and road build­ i n g . Rejects in the brickworks are ground and used here to provide a comparison.

Clay masonry units

Clay bricks and blocks are produced in solid or perforated form from clay, grog or air-entrain­ ing agents and water. D I N 1 05 part 1 - 6 defines the following types of clay masonry units, whose properties are influ­ enced by their density, proportion of voids, strength and shape (figs B 3 . 1 0 and 3. 1 2) :

--

-

_.

._-,

- --

-- �

8 3.5

49

Ceramic materials

1

Ordinary ceramics

1

1

I

1 pEarthenware 1 1 dStoneware 1 b n d y e se y d u b o s or ������O���==� �====�������O���==� 1�===r� Non-whi t ete-Ibringght- I 1 Non-whi te-Ibringght- I burning 1 1 Whiburni burningte- 1 1 Whiburni I 1 1 Refractory I 1 Engineering Technical ckworks 1 Briproducts " "p.:.ro:..: d:..:u-=-ct.:: :.:s-. , bricks, brick (hard) porcelain ---Chamotte, sisl teri­ Clay bricks mani t e, gani Hol l o w cl a y blocks for floors bricks Clay roof tiles Clay pipes f-round pipeson asHalcabl e protecti

·

•

•

•

•

•

J

slips Cleaved flags briEngicksneeri fornflgooring Viware trified stone­ ware pi(e.pges). stone­

Part 1 Clay bricks; sol id bricks and vertically perforated bricks: solid bricks (Mz) vertically perforated bricks (HLz) brick panels ( H LzT) hand-moulded bricks, specials facing bricks (VMz, VHLz) engineering bricks (KMz, KHLz) Part 2 Clay bricks; lightweight vertically per­ forated bricks Part 3 Clay bricks; hig h-strength bricks and high-strength engineering bricks Part 4 Clay bricks; ceramic eng ineering bricks: ceramic solid engineering bricks (KK) ceramic vertically perforated engineer­ ing bricks (KHK) Part 5 Lightweight horizontally perforated bricks (LLz) and l i ghtweight horizontal­ ly perforated brick panels (LLp) Part 6 Clay masonry units - high-precision units: solid high-precision bricks (PMz) vertically perforated high-precision bricks (PHLz) high-precision facing bricks (PVMz)

B 3.7 50

1

Clay ceramic materials

1

Fine ceramics

1 1 pEarthenware 1 1 dStoneware b u y y s d e e o ns ro b d �===r����i��O���==� �====�������O��==�==� 1 Non-whi White-ng 1 Non-whi White-ng burningte­ 1 1 burni 1 burningte- 1 1 burni 1 I I 1 Stoneware Pottery 1 1 (Stoneware wals l Porcelain v i t ri f i e d) or and fl o or ti l e 1 products semi-porcelain Fine terracotta L

Stove tiles Flowerpots Faience Terracotta

1 Special ceramics 1

I

Sinks Laboratory worktops Chemi cal apparatus

Wall tiles Washbasins Sinks

panels of high-preci sion bricks (PHLzT) high-precision engineering bricks (PKMz) high-precision specials

•

The standardised designation of the various types of clay bricks makes use of the following system: part 2 D I N 1 05-Hl z W 6-0.8-1 0 DF (300) , the meaning of which is as follows: D I N part, D I N No. code for specific type of clay brick perforation size A, B, C , W ( i .e. proportion of perforations) compressive strength class (N /mm2) density class (kg /dm3 ) format and wall thickness (mm) Properties

The d ifferences between the physical proper­ ties are evident from the basic c lassification into solid, perforated and engineering bricks: •

1

Sol i d bricks exh i b it a proportion of perfora­ tions on the bed face amounting to 0-1 5%

B 3. 8

•

Glassoxicerami cs, 1 d i s ed ceramics Cerami c components for telnseand communi c ati o elrinegctrical englneeHihiggh-temperature h- and very materials B 3.6

and are fired at temperatures of 900-1 1 OO°C. The applications include masonry, arches, i nfill panels and columns. Perforated bricks can be produced in the form of vertically perforated bricks with a pro­ portion of perforations on the bed face amounting to max. 50%. They are used for external and partition walls. Engineering bricks are fired up to the sinter­ ing limit and can be produced with or without perforations. They are heavy, dense, hard and frost-resistant, and emit a high-pitched sound when tapped. They are used in water­ way and canal engineerin g , also for floors and facades.

Clay bricks with a low density exhibit better thermal insulation properties, and the shape and arrangement of perforations contributes to this. Pores in the bricks are created by adding air­ entraining agents to the raw materials, e.g. polystyrene beads (0.25% by mass) , sawdust or recovered stock « 6% by mass) from papermaking. Their complete incineration in the tunnel kiln leaves behind small air pores

B 3.9

Ceramic materials

Density classes available [kg/dm"]

Clay brick type

Type code

Verticcalalllyy perforated perforated faci bricnks9 bricks Verti Sol bricnks9 bricks Soliidd faci Vertically perforated en9ineering bricks Lightweight vertically perforated bricks Brick panels Sol idcbriallycksperforated bricks Verti Solidcengi neering bricengi ks neering bricks Verti ally perforated Sol id engic vert. neeriperf. ng briengicksneering bricks Cerami

HLzA, HLzB -1.66 1.1.24-1. VHLzA, VHLzB Mz 1.6-2.0 (2.2) VMz KHLzA, KHLzB " 1.9 HLzA, HLzB, HLzW 0.6-1.0 HLzT 0.8-1.0 1.2-2.2 Mz, VMz HLz, VHLz KMz KHLz 1.6-2.2 KK KHK

(Compressive) strength classes available [N / m m"]

4-28 12-28 12-28 28 4-12 6-28 26-60

60 B 3.10

that lower the density of the clay bricks. Never­ theless, their great mass is suitable for storin g heat. The clay brick then emits t h e heat into the interior at a later time. The fine capi l lary pores absorb moisture and act as a buffer in the case of fluctuations in the humidity of the internal air. Clay bricks are classed as incombustible mate­ rials of building materials class A i . High-precision vertically perforated bricks with integral thermal insulation These newly developed, lightweight, vertically perforated clay masonry units have a low den­ sity (0.65 kg /dm3). They consist of air-entrained clay bricks whose perforations are filled with perlite. This enables thermal conductivity val­ ues of around 0.09 W/mK to be achieved . For a wall thickness of 365 mm and plaster/render on both sides, the U-value i s then just 0.23 W/m2K. The high-precision vertically per­ forated bricks from some manufacturers can even achieve such values without a filling of insulating material. Consequently, sing le-leaf external wall constructions with this sol id wal l material can assume the thermal insulation role at the same time. This material represents an alternative to lightweight assemblies and ther­ mal insulation composite systems. Applications

The DIN 1 05 designations also imply the type of application. According to the standard , clay masonry units are divided into backing, facing and engineering bricks. Perforated clay bricks require weather protection in the form of render or a frost-resistant external cladd i n g . In princi­ ple, the low water absorption of sintered clay masonry units makes them suitable for facing masonry i n the form of frost-resistant rai n pro­ tection . This protection is g uaranteed by flush, water-repellent mortar joints between the masonry units. The colour and pointin g of the mortar joints influence the character of the wal l surface. To create a flush mortar joint i t i s essential for the joint to be fully filled with mor-

tar. After the mortar has stiffened but is not fully set, a suitable tool ( e . g . piece of plastic hose) is run along the joint to compact the surface of the mortar, which results in a l i g ht concave fin­ ish to the joint. If this is carried out after the mortar has set, the mortar must first be raked out to a depth of 1 5 -20 mm before the joint is pointed with new mortar and finished as described above.

B3.11 cperforated classificaticloany ofengicerami cngmateri als BB 3.3.3.867 Systemati Verti c al l y n eeri bri c k lh-preci ow claysioblnockvertiforcalflolyoriperforated ng purposes B 3. 9 HiHol g clay brick with i n tegral perl i t e thermal i n sul a ti o n B 3.10 speci Densiftiicescland compressi vtoe DIstrength classes of a y bri c k types N 105 B 3.11 Germany, Garden Room, KOhnen House, Kevelaer, 1998, Hei n z Bi e nefel d B 3.12 DIPhysi al parameters of clay brick masonry to N Vc4108-4 B

Efflorescence

Discoloration of masonry in the form of salty deposits is seldom a result of the soluble sub­ stances contained in the building material itself. The moisture that penetrates the clay bricks by capillary action can dissolve the salts and carry them to the surface. However, proper firing converts and composes the majority of such soluble salts in the mass of c lay. So the cause of efflorescence is more likely to be found in the type of mortar used and the use of the incorrect bricks for the degree of climatic expo­ sure for a certain type of construction and type of joint.

Hollow clay block floors and wall panels

Clay blocks are produced for placing between reinforced concrete ribs (fig . B 3.8) . They have a large proportion of perforations which reduc­ es the overall weight and improves their sound insulation qualities. The forms and d i mensions of this ord inary ceramic building material vary consi derably, but the type of construction is based on the combination of concrete ribs, steel or timber beams and the clay blocks placed in the i ntervening spaces (see " I nter­ mediate floors", p. 1 65). The standard makes a d i stinction between structural clay blocks to D I N 41 59 for hollow clay block floors, reinforced concrete ribbed floors and prefabricated wall panels. Such clay blocks can accommodate flexural compressive

Density

[kg/m"]

Design value for thermal conductivity 1 [W/mK]

Water vapour diffusion resistance index [-]

Solid, vert. perforated and ceramic engineering bricks 1.9206 2200 50/100 2000 0. 50/100 1800 0.81 50/100 Solid and vertically perforated bricks 2000 0.0.9861 5/10 1800 5/10 5/10 0.0.5688 1600 1400 5/10 0.50 5/10 1200 Lightweight vert. perforated bricks with AlB perforations 5/10 0.0.4425 1000 900 5/10 0. 3 9 800 5/10 700 5/10 0.36 Lightweight vertically perforated bricks type W 0.0.3369 1000 5/10 900 5/10 0. 3 3 800 5/10 0.30 700 5/10 valuesusiginvgenlighere be reduced 0.The 06 WdesiImKgnwhen htweimay ght mortar to DINby1053-1. B 3.12 1

51

Ceramic materials

8 3. 1 5

8 3. 1 3

stresses and are provided with mounting strips or supports on the sides. Complete or partial mortar filling of the vertical joints is possible. Non-structural clay blocks to DIN 4 1 60 can carry loads during installation only.

natural colour is red , but clay roof tiles can be produced in other colours by a number of methods, e . g . glaz i n g , steam treatment, engobe finish. Newly developed coati ngs exhi b it the Lotus Effect, which i ncreases the durabi l ity of the roof tile - rainwater simply rins­ es any dust and dirt away.

Clay roof tiles

Requirements

No deformations or cracks are permitted in the Clay roof tiles are planar, ordinary ceramic g laze or engobe finish that may impair the serv­ products for the rainproof covering of pitched roof surfaces and facades. These units are fixed iceabi l ity and weathering resistance. Clay roof individually and overlap in such a way that rain­ tiles must be dimensionally stable, i mpervious to water, frost-resistant and be capable of car­ water is rel iably drained (see "The building rying a specified minimum load. Type of tile, envelope" , p . 1 23). We classify clay roof tiles according to their production, shape and dimen­ type of roof covering and roof pitch are interre­ lated. Specifying a minimum (recommended) sions (fig . B 3. 1 6) . roof pitch guarantees a rainproof construction. The construction of the roof surface, the loca­ Wire-cut clay roof tiles tion of the building and the local c l imate are Wire-cut clay roof tiles generally have a simple further factors that will have an influence. geometry and include the following types: •

•

Non-interlocking clay roof tiles: plain tiles (bullnose tiles) pantiles I nterlocking clay roof tiles (one side rib only) : wire-cut interlocking tiles

Pressed clay roof tiles Pressed clay roof ti les can be produced with tapering forms or one or more interlocking head , tai l and side ribs. •

·

Non-interlocking clay roof tiles: flat pan tiles under-and-over tiles I nterlocking clay roof tiles: wire-cut interlocking tiles Roman tiles interlocking tiles with twin ribs interlocking pantiles interlocking flat pan tiles tiles with adjustable head lap

In addition, special tiles are available for use at junctions, terminations and transitions, e . g . verge, ridge o r wal l . Standard a n d special clay roof tiles are covered by D I N EN 1 304. There are no standardised dimensions, merely recom­ mendations for manufacturers. The standard ,

52

Stoneware pipes

Stoneware pipes are used for draining land and for drainage networks. When laid in the ground they exhi bit excellent durability ( 1 00+ years), good chemical resistance (ph 0-1 4) , high mechanical strength, imperviousness and high hardness values. The raw material for their manufacture consists of clay, water and chamotte (refractory clay as grog ) ; the latter is responsible for the stabil ity and dimensional stability. Worm extruders compress the plastic mass, which also has any air inclusions removed in a vacuum chamber. The spigot­ and-socket joints are formed in the same oper­ ation. Depending on the nominal d iameter, there are various coupling systems with plastic sealing elements available. Each pipe is glazed i nternally and externally prior to firing. Every pipe is stamped on its shaft with the European standard D I N EN 295, the manufac­ turer's I D , the nominal diameter, the load-carry­ ing capacity in kN /m and the coupling system.

a

b

c

d

�o

o 8 0 0�

e

9

h

8 3. 1 6

Ceramic materials

eng ineering bricks and terracotta tiles can be used as floor coverings.

Ceramic floor and wall finishes

Ceramic tiles and flags are classified accord­ ing to the corresponding quality demands of DIN EN 1 44 1 1 and their production and mois­ ture absorbance (fig . B 3. 1 8) .

Wire-cut tiles and flags

Applications

The firing temperature and porosity of the body influence the water absorption. Tiles and flags with low water absorption (E s: 3%) have a fine-grained, sintered body. The voids are filled and the surface contracts during firing to give this ceramic building mate­ rial high strength , frost resistance and resis­ tance to alkalis and acids. This includes stone­ ware (8TZ) with glazed (GL) and ung lazed (UGL) surfaces. Tiles and flags with high water absorption (E > 1 0%) are fired below the sintering limit. They therefore exhi b it a pore volume of 20-30%, After the first firing (biscuit or bisque firin g ) , the glaze is applied which seals the tile after the second (glost) firing. This group of products includes stoneware tiles (8TG) with a white body, and earthenware tiles ( I G ) with a col­ oured body. As these products are not frost­ resistant, they may only be used internally. Further selection criteria are the type of loading as well as the assessment of anti-slip proper­ ties. The displacement volume of profiled tiles is the volume between the traffic surface and the water run-off level. This is important, for example, for floor coverings in swimming pools and industrial buildings. The properties and specifications give rise to the potential applications: Stoneware and earthenware tiles can be used as wall finishes, also small-format stoneware products (ceramic mosaic) , Ceramic cleaved flags , stoneware tiles, small­ format stoneware products, fine stoneware,

A

B

Wire-cut tiles and flags belong to the group of ordinary ceramic products that are fired above the sintering l imit. The body is coloured. Their production is primarily in the form of a double flag of plastic clay mass that is separated after firing with a hammer-blow to form a cleaved or split flag. R i bs on the rear face form an i nter­ lock with the mortar bed. These tiles and flags are suitable as wal l and floor finishes, facades, terraces, for industrial plants and swimming pools. The split flags must be resistant to temperature fluctuations, alkalis and acids. They are avail­ able in various formats, colours and dimen­ sions, glazed or unglazed. Frost resistance is only req uired for split flags of group AI, I n d ivid­ ual flags are rare and are often re-pressed to improve their properties. Dry-pressed tiles and flags

Dry-pressed ti les and flags belong to the group of fine ceramic products. Clay, kaolin, finely m i l led quartz sand and chalk are mixed with water to an even consistency. Afterwards, hot air is blown into the mix in a spray tower to remove the water. The powder-like, fine-grained mass i s pressed into moulds at high pressure prior to firing. These tiles and flags are availa­ ble in g lazed, partially g lazed and ung lazed versions. The surface of the ung lazed products can be smooth, rough or textured depending on req u i rements. Other production methods are in use but these play only a m inor role for building products.

Tiles and flags can be applied to horizontal or vertical surfaces, Laying in a thick bed requires

Wire-cut tiles and flags

Group AI

Group A l l •. ,

Group A l l •. ,

Group A l I I

Appendix A

Appendix

Appendix

Appendix F

( D I N EN

( D I N EN

( D I N EN

(f) � +0

ID

0; ;::

ID C

a

. E ,;; 0,5 %

B 186-1)

0

187-1)

Group A I I "2 Appendix C

Group A I I .' 2 Appendix E

( D I N EN

( D I N EN

Group

Group BI

B

186-2)

II

.

Group

B

l lb

Appendix J

Appendix K

( D I N EN

( D I N EN

(DIN EN

0,5 B 3 176) ib % ,;; E <

177)

178)

1973,

Jmn Utzon

Selection of clay roof tile profiles: a interlocking tile b flat pan tile c un der- and over-tiles d bullnose tile e pantile f wire-cut interlocking tile g flat roof tile with interlocking ribs on all sides h tile with adjustable head lap

B 3,17 B 3.18 2002,14411 B 3,19

Clay roof tiles as roof covering and facade clad­ ding on houses near The Hague, Netherlands, MVRDV

Classification of ceramic tiles and flags to

Holiday home, Muuratsalo, Finland,

Alvar Aalto

2004 1953,

(the DIN numbers valid up to

are given in brackets)

( D I N EN

188)

(9 (9 1- (Jl (f)

Group B i l l

(f) � Appendix L Q) +=' ( D I N EN

� �

ID '"

159)

�;:: ID�

ID r. c t::

Group

Appendix

Tile-covered roof of the Sydney Opera House, Australia,

187-2)

Appendix G

176)

Clay roof tiles in various colours Stoneware pipes

Group III E > 10%

Group I E $ 3%

N I(Jl

Group ". 3% < E $ 6%

Group ". 6% < E $ 1 0%

Moisture absorption Moulding process

Dry-pressed tiles and flags

BB 3.13 B 3,14 3.15 B 3.16

EN

Laying

121)

B 3.17

a solid substrate on which the 1 0 -20 mm thick layer of cement mortar is laid in order to even out any irregularities. Laying in a thin bed is carried out using hydraul i c mortar or a suitable adhesive. The 2 - 4 mm thick layer of mortar/adhesive calls for a flat, soli d substrate.

.8 '"

%

(Jl W

H

( D I N EN

C

Tiles and flags produced with other methods

Group Cl

Group C I I

.

Group C l l b

Group C I I I

B 3,18

B3.19 53

Building materials with mineral binders

8 4. 1

8 4. 1

Building materials with mineral binders have been known for thousands of years. The Phoe­ nicians, Egyptians, Trojans and Greeks were fami liar with mortar made from gypsum and lime, which they used for masonry and also as a protective layer of p laster or render. It has been proven that Greek builders used lime mortar in the 2nd century BC as an infi l l materi­ al for rubble stone masonry. The Romans refined this method in order to erect great structures such as the Colosseum in Rome. They called it opus caementitium, a mixture of lime (as the binder) , pozzolana and tuff with aggregates of gravel and stones, and used it ­ carefully compacted - as an infill material between masonry facings of clay bricks or stone. The clay bricks were sometimes given a protective covering of render, or a stone fac i n g . For uti lity b u i l d i n g s a n d foundations opus cae­ mentitium was used alone, cast in timber form­ work. In the year 1 3 BC Vitruvius described the composition of the hydraulic mortar which at that time was already achieving strengths equivalent to those of modern-day concretes (fig . B 4 ) . The Pantheon in Rome with its 43 m span, built in 27 BC, remains to this day the most i mpressive example of this method of construction . However, after the downfal l of the Roman Empire the knowledge about opus cae­ mentitium was lost and was not red iscovered until the 1 9th century.

From t h e M i d d l e Ages onwards, gypsum was often used as a binder for screeds, mortars and, later, for scagliola. The panels of timber­ framed buildings were filled with gypsum mor­ tar reinforced with straw or horsehair. The French engineer Bernard Forest de Belidor ( 1 698-1 761 ) described the composition of mor­ tar and was the first person to use the term beton ( concrete) to denote a mixture of water-resistant mortar plus aggregates. I n 1 824 Joseph Aspd i n was granted a patent for Port­ land cement, a mixture of fired lime in powder form p l us clay. Auguste Perret ( 1 874-1954) was one of the first architects to use concrete for housebuilding and consistently demonstrated the possibilities of this material for industrial structures. The buildings of the Expressionist architects and others like Frank Lloyd Wright ably demon­ strated the mouldability of concrete. The 1 950s saw the appearance of ultra-thin , efficient shell structures. Le Corbusier and Louis Kahn employed fair-face concrete surfaces con­ sciously as a means of aesthetic design.

8 4.2

8 4.3

=

Mineral binders

Binders hold together the grain-type constitu­ ents (agg regates l ike sand or gravel) of mortar and concrete. A diverse set of properties, e . g .

Reinforced concrete vaulting, wine cellar, Pamplo­ na, Spain, 1 999, Jaime Gaztelu, Ana Fernandez

8 4.2

Opus Caementitium,

Caracalla thermal baths,

Rome, Italy, AD 2 1 7 8 4 .3

Reinforced concrete structural frame, former Fiat factory, Lingotto, Turin, Italy, 1 927, Giacomo Matteo Trucco

8 4.4

54

Composition of m ineral binders

Building materials with mineral binders

I gneous rocks

Mica

Marl

Loam

I

Firing

1-

Firing

Slaking

Slaking Cement

8 4.4

strength, vapour permeabil ity, compressive strength and elasticity, are controlled via the chemical curing process (fi g . B 4.6) . Gypsum

Gypsum is a natural substance, a compound of calcium sulphate ( lime) and water: CaS04 . 2H p (hydrated calcium sulphate). In order to obtain a form of gypsum that will cure ( i . e . set hard), the natural gypsum is crushed, ground and subsequently fired i n rotary kilns at tem­ peratures between 300 and 1 000°C. This drives off the bound water of crystallisation (the extent depending on the temperature) to pro­ duce the different types of gypsum for build i n g , which are classified accord ing t o the hydration stages of the calcium sulphate. The proportions of anhydrite (CaS0 4 ) without water of crystalli­ sation and hemihydrate in the gypsum deter­ mine the properties and the curing behaviour. Hemihydrate plaster, for example, is produced by firing at low temperatures, anhydrous gyp­ sum plaster at high temperatures. Adding water causes the gypsum to harden on expo­ sure to the air and, with the simultaneous development of heat, to form natural gypsum again, i.e. the firing process is reversed during the hardening reaction by integrating the mix­ ing water as water of crystallisation. The processing of gypsum by means of firing, mix­ ing and curing therefore represents a closed cycle. Calcium sulphate is also formed as a by-prod­ uct of a number of technical processes, e . g . flue gas desulphurisation a t power stations fired by fossi l fuels. The moist so-called desul­ pho gypsum obtained must first be dried, but like natural gypsum it is suitable for a mu ltitude of gypsum products. Properties and applications Additives and the water/gypsum ratio influence the strength , workability and porosity of the hardened material. Gypsum does not shrink during processing and has a positive effect on the interior c l imate thanks to its abil ity to absorb and release moisture. However, as constant contact with water would d issolve the gypsum , i t is unsuitable for wet rooms. Gypsum mixed with various aggregates is used for plastering

interior surfaces. The raw material is used for manufacturing a multitude of products, espe­ cially boards, masonry units and moulded parts. These products are fire-resistant because upon exposure to heat the water stored in the crystals is released again. In concrete mixes the add ition of gypsum retards the rate of cur­ i n g . The most important products include: scagliola, stucco plaster of Paris, ready-mixed plaster, bond­ ing plaster, machine-applied plaster browning plaster, joint plaster, fi l ler/stopper anhydrite bi nders prefabricated gypsum products Anhydrite binders Anhydrite binders are produced from natural deposits of anhydrite or from synthetic anhy­ drite, a by-product of various chemical proc­ esses. They harden in the same way as normal gypsum products. Owing to their low solu b i lity, activators in the form of alkaline substances (e.g. lime or cement) or salty substances (e.g. sul phates) must be added in order to bring about a period of hydration appropriate for the work. Anhydrite binders are used for plaster mixes (see "Surfaces and coatings", p. 1 90) , screeds, masonry units and wall panels.

lime represents a closed cycle because the final outcome of the whole process is limestone again. Hydraulic limes Natural hydraulic l imes are produced by firing marlaceous limestone at temperatures of up to approx. 1 250°C. This produces fired lime and c l inker mi nerals, which are also found in cement. D uring the slaking process the fired lime reacts with water to form calcium hydrate (Ca(OH) ) whereas the c l inker m inerals remain 2 ' unaltere d . Hydraulic l imes consist of mixtures of calcium hydrate, which hardens in the air through car­ bonation, plus hydraul ically hardening pozzola­ na, which is found in volcanic cinder (scoria) or industrial slag. As the proportion of pozzolana in the mixture increases, so the strength of the hydraulically hardening lime rises and with it the capacity to harden in air, but also underwa­ ter, after a fast i nitial set. The setting time is reduced accord i n g ly. Accord ing to DIN EN 459 we therefore d istinguish between hydraulic lime 2 , hydraulic lime 3.5 and hydraulic l ime 5 . The latter is also known as masonry l ime.

Limes are used for mortar, but also i n pure form for thin coatings. The quality req uirements are laid down in D I N EN 459.

Lime

The limes used in building are mixtures of the oxides and hydroxides of calcium, magnesium, s i l i con and iron. Lime can be found in nature in the form of limestone (CaC03) and dolomite. Building l imes are d ivided into non-hydraulic and hydraulic varieties owing to the different setting processes. Non-hydraulic limes Non-hydraulic lime (high-calcium lime) is pro­ duced by firing limestone at approx. 900°C. Afterwards, the fired lime (CaCO) is "slaked" by adding water. The considerable heat develop­ ment and increase in volume produces slaked lime (Ca(OH) ) which is used as a binder for 2 ' mortar and coatings. I n order to harden, the mortar requires water and carbon dioxide from the air so that carbonic acid can carbonate the lime. The processing of

The non-hydrau lic l imes include: dry hydrate, white lime dolomitic lime, dolomitic hydrate •

The hydraulic l imes i nclude: water b urnt lime, slaked lime hydraulic lime, masonry lime •

Magnesia cement

The production of magnesia, or Sorel 's, cement requires magnesite (Mg C03 ) or dolomite (CaMg(C03 ) ) ' Firing at temperatures between 2 800 and 900°C produces magnesium oxide, so-called caustic magnesia, which reacts with water. Firing magnesite at temperatures exceed­ ing 1 600°C produces sintered magnesium oxide, which can be used for refractory bricks. This material no longer reacts with water. Caustic magnesia is used as a binder in

55

Building materials with mineral binders

Binder

Cement Gypsum Non-hydr. lime Hydr. lime Anhydrite Magnesia

Density in cured state

Minimum compressive strength classes

Bulk density

[kg / m"]

[N / mm'l

[kg / m"]

2900-3200 32.5; 42.5; 52.5 850-1600 10; 40 ' 1000 1000 2; 3. 5 ; 5 2900-3000 5; 20 2000 5; 50

approx.

approx.

l '

960-1200 600-1200 880-1120 640-700 800-1300 400-650

, The compressive strengths of non-hydraulic limes and gypsums are not standardised; average compressive

screeds and wood wool slabs. The addition of salt solutions forms a polishable compound within just a few hours. A d iverse ran ge of fill­ ers, e . g . wood chips, can be mixed i nto the magnesia cement without causing any signifi­ cant loss of strength. Cement

Cements are hydraulic binders for mortar and concrete. They consist of compounds of calci­ um, silicon, aluminium and iron oxide. The oxide composition varies depend ing on the type of cement. D I N EN 1 97 divides the types of cement into five main groups (CEM I-V) : Portland cement, Portland composite cement, blast-furnace cement, pozzolanic cement and composite cement. The production of Portland cement, the most widely used type of cement, involves firing a mixture of lime and clay at 1 450°C, i . e . above the sintering limit. Afterwards, the resulting cement clinker is ground in ball mills - requir­ ing a great deal of energy - to form a fine pow­ der, the cement. The high strength of cements distinguishes them from other hydrau lic binders. The addition of water enables the cements to set both in the air and underwater while giving off heat - a chemical-physical process known as hydration. It begins as soon as the first water comes into contact with the grains of cement. At first this produces cement paste, which slowly changes from the l i q u i d or pulpy state to the solid hydrated cement. The concrete

84.5

i s placed and compacted d uring this hardening and setting process. 0 1 N EN 1 97 specifies mini­ mum times for the onset of settin g , which lie between 45 and 75 minutes depending on the cement strength class. The addition of about 35% gypsum prolongs the curing time. The cur­ ing to form a solid body is a longer process, which is essentially concluded after 28 days with the test for minimum compressive strength. The following conditions must be ful­ filled during the hardening process: sufficient mixing water for wetting and hydra­ tion high humidity, protection against drying out, wetting with water sometimes req u i red temperature > 5°C, high temperatures accel­ erate the hardening process

strengths have been used here to provide a comparison.

84.6

frost resistance are achieved with a value � 0.6. The concrete strength classes to EC2, the strength classes of standard cements and the water/cement ratio are all interrelated.

White cement White cement has the same properties as Port­ land cement but owing to its lighter colour is preferred for fair-face concrete, terrazzo finishes, etc.

D I N EN 1 97-1 divides the cements into classes (Z) according to the minimum compressive strength (in N / m m2 after 28 days, standard prism 40 x 40 x 1 60 m m ) . Depending on the setting process of the various types of cement, the letter N describes a normal initial set and the letter R a high i n itial strength . The types of cement can be basically allocated to the follow­ ing strength classes:

Water/cement ratio The water/cement ratio (w/c ratio) describes the relationship between the quantity of water and Z 32.5 N; Z 42.5 N primarily blast-furnace cement weight of cement as a percentage. This ratio is Z 32.5 R; Z 42.5 R primarily Portland and critical for complete hydration. The value deter­ mines the porosity of the hydrated cement and Portland blast-furnace cement hence the strength. During hydration about 40% of the cement by Z 52.5 N; Z 52.5 R Portland cement only weight (w/c ratio 0.4) is chemically and physi­ cally bonded to the water. I n practice the values lie between 0.42 and 0.75. A hi gher w/c ratio Aggregates and additives/admixtures results in a hi gher porosity, d ue to the water­ filled pores, which impairs the properties of the The nature and size of the g rains added to the mineral binders to form the main constituent concrete. I mperviousness to water and good (65-80% by vol .) determine the properties of a mortar or concrete. ·

•

•

Aggregates

We d ivide aggregates for concrete into light­ weight, normal-weight and heavy aggregates accord ing to their density. Aggregates like sand and gravel consist of rounded, unbroken grains. Chippings and bal­ last, which are produced in mills by crushing larger rocks, are described as angular grains. This type of aggregate also includes grains obtained from recycled concrete.

8 4.7 56

8 4.8

Building materials with mineral binders

Lightweight aggregates Mortar and concrete with lightweight inorganic aggregates exhibit i mproved thermal insulation properties and better behaviour in fire. Tuff, pumices and scoria are some of the natural lightweight aggregates; the man-made ones include expanded clay, expanded shale, foamed slag, and clay brick chippings. I n cer­ tain applications it is also possi ble to find wood wool, wood chips and plastics such as polysty­ rene beads. Normal-weight aggregates According to their average densities, blends of gravel, chippings, ballast, mineral recycling materials and sand are regarded as normal­ weight aggregates. Heavy aggregates Iron ores, lead shot, sulphates and barytes are heavy aggregates that can shield radioactive radiation and are therefore used in the con­ struction of nuclear reactors and x-ray faci l ities. Grading curves The proportions of the various grain sizes in a graded aggregate have a major influence on the material properties. They govern the worka­ bility and compactability of the wet concrete and the quantities of water and binder required. In order to achieve high density and high strength with as little bi nder as possible, con­ crete aggregates to D I N 4226 should form a dense structure of coarse and fine particles and have a small surface area that must be coated by the binder. The smal ler grain sizes are responsible for good workability and com­ pactability. In reinforced concrete the largest grain should be smaller than the clear spacing between the reinforcing bars and between rein­ forcing bars and formwork (concrete cover) so that an adequate covering of binder is always guaranteed. The maximum size of aggregate in reinforced concrete is usually approx. 32 mm, in mortar approx. 4 mm. Standardised grading curves specify the com­ position of the graded aggregate. Graded aggregate is sieved with a standard set of sieves (nine sieves with mesh apertures from 0.25 to 63 mm) . The result allows us to deter­ mine how much (in % by mass) of the total mass of aggregate has passed each sieve and whether the mixture can be i mproved by add­ ing certain grain sizes. Additives/admixtures

Chemical substances may be added to improve the concrete properties during working and in the finished state. Plasticisers ease the placing of the concrete. Accelerators and retarders enable the heat generation d uring setting to be adjusted to the external tempera­ ture (fig. B 49) . Pigments

Metal oxides can be used to produce coloured concrete products. Organic pigments on the

other hand, do not usually remain chemically stable in the cement mixture, and this limits the choice of colours.

Mortar

Mortar is a mixture of binder, water and sand, possibly also additives/admixtures to improve the properties. The constituents are either mixed on site or premixed at the works. As the composition of standardised mortars is more accurate in the works than on the building site, premixed mortars are preferred. We dis­ tinguish between several types of mortar: Ready-mixed mortars are ready-to-use standard mortars of groups 1 1 , I l a and I l l . They contain a retarder that maintains work­ abil ity for up to 36 hours. Premixed "coarse stuff" consists of a mix­ ture of non-hydraulic or hydraulic lime plus aggregates to which water and - depend­ ing on req u i rements - other binders are added on site. Premixed dry mortar is suppl ied in sacks or filled into the silos of on-site batching plants; water is added on site according to the suppl ier's i nstructions. I n on-site batching plants the raw materials are stored separately and then mixed on site with water in a predetermined ratio. Mortar can improve sound and thermal insula­ tion as well as fire protection. Depending on the application, we d istinguish between mor­ tar for masonry, renders and screeds. Mortar for masonry ensures shear- and compression­ resistant joints between the i nd ividual mason­ ry units. Mortar for renders - in the form of a thin, uniform coating - protects walls against the weather and mechanical damage, or forms a substrate for further work (fig . B 4 . 1 1 ) . Mortar for screeds serves as a wearing course or as a backing for the floor covering (see " F loors", p. 1 72 ) . Mortar for masonry

Mortar for masonry is d ivided into normal­ weight mortar ( N M ) , lightwei g ht mortar (LM) and thin-bed mortar (OM) (fig . B 4 . 1 0) . D I N 1 053-1 d ivides normal-weight mortars into a further five groups, distinguished accord ing to their binder and sand content. This leads to corresponding applications. Group I mortars may not be used in, for exam­ ple, walls more than two full storeys high and in walls < 240 mm thick. There are no such restrictions for group II and I l a mortars. Group I I I and I l i a mortars may not be used for the external leaves of double-leaf masonry walls. Lightweight mortars are defined as mortars with an oven-dry density < 1 .5 kg/dm3. If the value is below 1 .0 kg/dm3, the mortar i s c lassed as a thermal insu lation mortar that can be used for masonry with a low thermal transmittance.

Colour

Abbreviation

DeSignation

code Plasticiser

BM

yellow

Superplasticiser

FM

grey

Air enlrainer

LP

blue

Waterproofer

OM

brown red

Retarder

VZ

Accelerator

BE

green

G routing aid

EH

white

Stabiliser

ST

violet B 4.9

Min. 28-day compress. strength

Mortar for masonry, DIN 1 053 group

Suitability test IN/ mm>]

Quality test IN / mm>]

Min. adhesive shear strength

IN / mm>]

Normal,weight mortar I 3.5

2.5

0.1

7

5

0.2

III

14

10

0.25

ilia

25

20

0.3

7

5

0.2

14

10

0.5

lIa

Lightweight mortar LM 2 1 ; LM 36 Thin·bed mortar

B 4. 1 0

Type of mortar Mortar for render, DIN V 1 8550 class P I

P II

a

Non·hydraulic lime mortar

b

Hydraulic lime mortar

c

Mortar with hydraulic lime

a

Min. 28-day compressive strength, quality test

Mortar with masonry lime

2.5

or mortar with render & masonry binder

P ili

b

Lime cement mortar

a

Cement mortar with

10

lime hydrate b P IV

PV

Cement mortar

a

Gypsum mortar

b

Gypsum sand mortar

c

Gypsum lime mortar

d

Lime gypsum mortar

a

Anhydrite mortar

b

Anhydrite lime mortar

2

2

B 4. 1 1

B 4.5

Structural shell, bus terminal, Casar de Caceres, Spain, 2003, Justo Garcia Rubio

B 4.6 B 4.7

Physical parameters of mineral binders Reinforced concrete structure with artistic use of joints and formwork, Stadelhofen railway station, Zurich, Switzerland, 1 990, Santiago Calatrava

B 4.8

B

4.9

Villa Savoye, Poissy, France, 1 929, Le Corbusier Designation of concrete additives/admixtures to D I N E N 934-2

B 4 . 1 0 Mortar for masonry, D I N 1 053 groups B 4. 1 1 Mortar for render, D I N V 1 8 550 groups

57

Building materials with mineral binders

Compressive strength class for normalweight concrete

Compressive strength classes to EC2 '

Normal-weight concrete

C12/15

Compressive strength, characteristic value '

Compressive strength, mean value

Tensile strength, mean value

IN / mm"]

IN/mm"]

IN / mm"]

IN / mm"]

12

20

1 .6

26 000 27 500

Modulus of elasticity

C 1 6/20

16

24

1 .9

C20/25

20

28

22

29000

C25/30

25

33

2.6

30500

C30/37

30

38

2.9

32 000

C35/45

35

43

3.2

33500

C40/50

40

48

3.5

35 000

C45/55

45

53

3.8

36000

C50/60

50

58

4.1

37 000

1 The characteristic compressive strength corresponds to the strength of a cylinder, 1 50 mm dia. x 300 mm long,

28 d old, the second value to the strength of a cube, 1 50 x 1 50 x 1 50 mm side length, 28 days old.

Thin-bed mortars with aggregates < 1 mm are suitable for masonry with bed joints and per­ pends < 3 mm. The low proportion of joints results in a lower thermal transmittance through the wal l .

Concrete

These days, concrete is produced with a high q uality and used for a multitude of different applications. The architectural options extend from mechanical surface treatment to printing to the use of special types of cement, e . g . white concrete (fi g . B 4. 1 4). Tadao Ando is a proponent of the aesthetic use of fair-face con­ crete, wel l known for his skilful use of surface treatments and the arrangement of formwork ties as a design element (fi g . B 4 . 1 2) . Mixtures of cement, aggregates a n d water harden to form a man-made stone - concrete. Accord ing to the density of the aggregates, we class concrete as normal-weight, lightweight or heavy. The aggregates, cement and additives/ admixtures determine the properties of the con­ crete. As a rule, 1 m3 of normal-weight (wet) concrete comprises 2000 kg gravel, 250-400 kg cement plus 1 50 kg water. Production

Concrete components can be cast on site (in situ concrete) or prefabricated off site and then transported to the building site (precast con­ crete). Formwork Wet concrete ( i . e . stil l workable) can be mould­ ed i nto virtually any shape. The formwork acts as the mou ld and is usually made from timber or wood-based products. I n the case of larger components the timber formwork is supported by steel props and frames. Threaded fasteners (formwork ties) pass through the component, e . g . a wal l , and d i stribute the pressure of the wet concrete. This leaves holes in the concrete after the formwork has been struck and these holes are a typical feature of fair-face concrete surfaces, just like the material and surface tex­ ture of the formwork. The striking times for B 4. 1 5

58

B 4.13

formwork are standardised depending o n the type of component and the strength of the cement. Placing and compacting Normally, the concrete is placed in the form­ work with the help of hoses and pumps. Once in position, it is compacted with vibrating plant and other equipment in order to minimise the air content, create a good surface finish and generate a structural bond with the steel rein­ forcement. Self-compacting concrete The use of self-compacting concrete (SCC) is growing. The consistency of this concrete ena­ bles it to be placed in the formwork without the need for any additional mechanical compact­ ing measures. The fluid consistency is achieved by adding plasticisers. Self-compact­ ing concrete is ideal for fair-face concrete and components with complex geometry. However, there is sti l l no standard covering loadbearing components made from this material . Curing The temperature and humidity of the air influ­ ence the hardening process and the properties of the concrete. Concrete components must therefore be properly cured for at least seven days after pourin g . In order to prevent prema­ ture drying-out, concrete is therefore left in the formwork and surfaces are covered with sheet­ ing or sprayed with water or a curing agent. The striking times depend on the dimensions of the component and the strength class of the concrete. Reinforcement Concrete has a low tensile strength but a high compressive strength (fi g . B 4 . 1 3) . Providing reinforcement in the form of steel meshes and/ or bars creates a composite material which, due to the bond between the steel and the hardened cement, achieves high tensile and compressive strengths. The steel reinforcement also prevents excessive shrinkage cracking.

Building materials with mineral binders

B 4.12 Formwork tie holes left exposed in finished con­ crete wall, Koshino House, Japan, 1 984, Tadao Ando B 4.13 Compressive strength classes for normal-weight concrete to EC 2 B 4.14 White cement, white stone dust and white pig­ ments, Office of the Federal Chancellor, Berlin, Germany, 2001 , Axel Schultes B 4.15 Porous drainage boards laid in the formwork, holi­ day home near Flums, Switzerland, 2003, EM2N B 4.16 Physical parameters of concrete in relation to the aggregate B 4.17 Masonry units (cement binder + natural aggre­ gate) , New Synagogue, Dresden, Germany, 2001 , Wandel Hoefer Lorch + Hirsch

Concrete with various aggregates

Density

Modulus Compress. of elasticity strength

[kg m"l

[N/mm']

[N/mm']

1 300 1 800 5000 6500

1 .5 4.2 13 15

[kJ/kgK)

Heat storage index [kJ/ m3K)

0.10 0.21 0.55 0.65

1 .4 1 1 .30 1.10 1 .08

990 1 1 02 1 435 1 560

0.29 0.32 0.41 0.65

1 .52 1 .79 1 .92 2.10

1 553 2099 2495 2990

Thermal Heatconductivity capacity [W/mK)

Lightweight wood particle concrete

60% 43% 1 5% 11%

700 850 1 300 1 450

by vol. wood by vol. wood by vol. wood by vol. wood

Lightweight wood particle concrete

37% by vol. wood. 2 7 % b y vol. wood, 26% by vol. wood, 20% by vol. wood, 1

1 3% 30% 37% 48%

by vol. PCM by vol. PCM by vol. PCM by vol. PCM

+

phase-change material (PCM) ,

1 025 1 1 75 1 300 1 425

1 600 2200 3533 4433

4.1 6.2 1 2.2 15

PCMs are latent heat storage media that can absorb thermal energy over a certain range without a rise in tempera­ ture. This is achieved through a phase transition from solid to liquid. B 4. 1 6

Concrete cover The strongly alkali ne composition of the con­ crete protects the reinforcement against corro­ sion. However, over time carbon dioxide or chlorides from the surroundings (e.g. sea salt or de-icing salt) can penetrate the surface and together with moisture bring about chemical neutralisation of the outer layers of the concrete. In order to prevent such substances reaching and corroding the reinforcement, D I N 1 045 specifies minimum dimensions for the concrete cover. If these dimensions are not adhered to, the reinforcement may corrode , which leads to an increase in volume and to spal l i n g of the concrete. Important factors influencing the con­ crete cover are the exposure conditions and the diameter of the reinforcing bars.

crete). A new development is translucent con­ crete in which light-carrying fibres (e. g . g lass fibres) are used as an aggregate (see "The architect as building materials scout", p. 1 7) . Environmental compatability

The lion's share of the primary energy required for the production of concrete goes into the manufacture of the cement clinker. In order to avoid transportin g ready-mixed concrete over long d i stances, it is usual to set up a batching plant on large building sites. H i g h-qual ity con­ crete leads to more slender components and so the greater effort during construction is offset by lower consumption of materials and a longer service life. Recycling

Quality control Quality control measures guarantee the quality of the concrete during all operations because deviations from the standardised processes would mean that the concrete can no longer comply with the design requirements. For example, the concrete mix and its compressive strength are checked using test cubes prior to construction, and the production i s monitored constantly. Placing and curing of the concrete must be recorded accurately by the site staff responsible. Special types of concrete

In principle, concrete from demolished buildings can be reused for new concrete components. Up until now pieces from building debris have been mainly used in roadbuilding and for filling work, i.e. for low-grade operations ("downcyc­ l i n g " ) . It is already possi ble to examine the qual­ ity of the scrap material, however, and thus create the regulatory framework for the reuse of concrete as aggregate. But owing to its angular form and grading curve, concrete mixes with this aggregate require a h igher cement content. This nullifies the advantages of recycl i ng because the cement production is associated with a high energy i nput.

Properties and applications

Concrete is i ncombustible (building materials class A 1 ) and resistant to many aggressive substances. By choosing the right the mix, concrete can be made resistant to de-icing salts, impervious to water or gastight. Plain concrete components Concrete components without reinforcement are suitable for numerous applications:

External works: e . g . slabs and pavings, kerb­ stones, concrete blocks for embankments Services and shafts: waste water pipes, inspection chambers Floors: filler blocks for floor slabs Roof coverings: concrete roof tiles, available in similar formats to clay roof tiles, but also in large formats I nternal fitting-out: concrete blocks for walls, reconstituted stone blocks, floor finishes, stair treads Reinforced concrete components Loadbearing assemblies can be prefabricated from columns and beams in any form, e.g. to match the bendi n g moment d iagram. At the precasting yard formwork with multiple reuses can be worthwhile, especially in the case of components with complex geometry. Stair flights are frequently made from precast con­ crete. Precast concrete planks are precast with

The use of fibres made from g lass, synthetic materials, steel or carbon can further alter the properties of the concrete, e . g . increase the tensile strength, improve the i mpact toughness, reduce cracking. The addition of organic or inorganic fibres increases the strength of concrete. Fibre-rein­ forced components are more durable and can have more slender dimensions than those made from normal-weight concrete. Aggregates made from wood reduce the thermal conductiv­ ity and increase the specific heat capacity (fig. B 4.1 6) . Textiles can accommodate tension stresses and are not at risk of corrosion. They can be used to reinforce concrete with a small concrete cover and hence result in smaller and lighter concrete components (textile-reinforced con-

59

Building materials with mineral binders

tension reinforcement and then completed on site with a concrete topp i n g . Cavity facade designs can be erected with a facing leaf of precast concrete panels.

M ineral-bonded components

Mineral-bonded components exhibit high dimen­ sional accuracy because their manufacturing process using steam and pressure at a temper­ ature of 1 60-220°C minimises their shrinkage characteristics. They can be produced in vari­ ous sizes, densities and compressive strengths, with or without holes (fi g . B 4.20) . Lightweight concrete blocks

By using aggregates such as pumice or expanded clay, concrete works can produce a wide range of bricks and blocks for internal and external walls. Such components are char­ acterised by a low thermal conductivity. Aerated concrete blocks

d

B 4. 1 8

Aerated concrete consists of cement with fine­ grain substances such as quartz sand, fly ash and a blowin g agent. The production in an autoclave (high pressure plus high tempera­ tures of about 200°C) is only possible in a con­ crete works. The resultin g concrete contains up to 80% voids, which means a low density cou­ pled with good strength , plus good sound insu­ lation and fire protection characteristics. Masonry units and large-format panels for load­ bearing and non-load bearing walls can be pro­ duced from aerated concrete. Granulated slag aggregate units

These masonry units are made from granulated blast-furnace slag plus cement or lime as a binder. After mou l d i n g they are hardened in steam or gases containing carbonic acid . Granulated slag aggregate units exh ibit similar properties to calcium silicate bricks and blocks and are used for similar purposes. However, they have a lower thermal conductivity for the same density. As an alternative to concrete blocks, the curing of which is time-consuming and costly, the building industry has developed methods in which mineral binders are cured by steam. Automatic presses are used to produce, for example, masonry units, in economic formats with a high degree of dimensional stability. B 4 . 1 8 Mineral-bonded boards a Plasterboard type A b Flooring-grade board c Fibrous plasterboard d Cement fibreboard B 4 . 1 9 Type designations of gypsum plasterboards: comparison of EN 520 and D I N 1 8 1 80 B 4.20 Physical parameters of mineral-bonded masonry units B 4.21 Interior design with gypsum plasterboards, office building, Stockholm, Sweden, 1 997, Claessen Koivisto Runee B 4.22 Facade of cement fibreboards, warehouse, Laufen, Switzerland, 1 991 , Jacques Herzog & Pierre de Meuron

60

Calcium silicate units

Calcium silicate is a mixture of lime and sand that sol idifies upon slaking with water. I nitially, lime is the binder in the resulting mass, but fur­ ther heating in steam causes the lime hydrate to react with the sand particles to form hydrat­ ed calcium silicate. Bricks and blocks made from this material can be manufactured with very tight tolerances and achieve a high com­ pressive strength. Calcium silicate units are frost-resistant and suitable for facing masonry both internally and externally.

Mineral-bonded boards

Plasterboards

The rapid curing time of gypsum enables the cost-effective manufacture of a number of products, especially large-format boards for walls, floors and ceilings. Plasterboards are produced as an endless strip and laminated with cardboard both sides, which also encloses the two long edges. The lamination serves as reinforcement, accommodating tensile forces and enabl i n g longer spans. Plasterboards can be worked easily with simple tools, e.g. sawn, cut, drilled or routed. They can be fixed to metal or timber frameworks with screws or nails, to a m ineral substrate by bond­ ing with dabs of mortar. The main advantages of plasterboards are their low weight, good strength and low thermal conductivity. This material has a high proportion of macropores, which help to regulate the interior humidity. At high humidities they absorb moisture, and release it again when the air is drier. Further­ more, aggregates and fillers influence the material properties. Untreated plasterboards are vulnerable to the effects of water. Addition­ al protection can be provided by claddings, coatings or plaster. Plasterboards are also used as a cladding for fire protection purposes. The duration of fire resistance depends on the additives and the thickness. Types of plasterboard Gypsum plasterboards are ideal for internal use on horizontal and vertical surfaces. The type designations are given in D I N EN 520, which has replaced D I N 1 8 1 80 (which, how­ ever, is stil l valid until August 2006) . Capital letters indicate the performance features, which may also be combined. The following examples are supplemented by fig . B 4 . 1 9:

Type A deSignates standard boards whose good face forms a backin g for gypsum plas­ ter or coatings. Type F designates boards with a defined fire resistance; the gypsum core usually contains mineral fibres. Type H deSignates boards with a lower water absorption; these boards can be used in wet rooms . Plasterboards c a n be supplied in thicknesses from 9.5 to 25 mm. For production reasons the standard width of the boards is 1 250 mm, but 600 mm for boards 25 mm thick. The boards may measure up to 4000 mm lon g . Plaster­ boards must be stamped with EN number, manufacturer's name, date and type designa­ tion. Plasterboards can be further processed in the works and provided with holes or slots to suit particular applications. Gypsum wallboards Gypsum wall boards consist of gypsum to which inorganic fillers or fibres can be added.

Building materials with mineral binders

They have smooth, flat surfaces. To i ncrease their stability they are usually produced with tongue and groove connections on the edges. Gypsum wall boards can be used to construct lightweight, non-Ioadbearing walls (see "Walls" , p. 1 56) . The thickness varies between 50 and 1 50 mm. These boards are ideal for fire-resist­ ant walls. Ceiling boards The (usually) square ceiling boards are avail­ able for satisfying fire protection requirements, for sound insulation and as decorative ele­ ments. The numerous perforation patterns available open up a wide choice of surface and design options with different acoustic effects. Composite boards Boards for floors, walls and cei lings can be provided with plasterboard surfaces that are already bonded to an insulating material such as polystyrene or mineral-fibre sheets. (see "Floors", p. 1 74 ) . Fibrous plasterboards

Fibrous plasterboards consist of a mixture of gypsum and cellulose fibres. The fibres act l ike reinforcement and increase the strength of the board. Fibrous plasterboards can be obtained with larger cross-sections than plasterboards and in building materials classes A 2 and A 2 to DIN 4 1 02-1 . Two or three layers of fibrous plas­ terboards may be bonded together as an alter­ native to a cement screed. Mineral-bonded particleboards Mineral-bonded particle boards consist of approx. 25% by mass wood chips and 65% organic binders (Portland cement, gypsum, magnesia) plus additives. To form these boards the constituents are mixed with water, spread out and compacted under high pres­ sure. Mineral-bonded particle boards are suita­ ble for floors, walls and soffits internally or externally depending on the type of binder used.

Plasterboards to DIN 1 81 80 (valid until August 2006)

Plasterboards to DIN EN 520

Plasterboard

type A

Plasterboard with defined density

type 0

GKB

Plasterboard

Plasterboard for cladding

type E

Plasterboard with improved microstructure bonding of core at high temperatures

type F

GKF GKFi

Fire-resistant plasterboard Fire-resistant plasterboard, impregnated

GKBi

Plasterboard, impregnated

GKP

Plasterboard for plaster background

Plasterboard with reduced water absorption

type H

Plasterboard with enhanced surface hardness

type I

Board for plaster background

type P

Plasterboard with enhanced strength

type R B 4. 1 9

Type of masonry unit

Abbreviation

Density classes available [kg / dm"J

Compressive strength classes available [N / mm']

Calcium silicate

solid (high-precision) perforated and hollow (high-precision) tongue and groove system fair faced brick veneer brick

KS, KS (P) KS L, KS L(P) KS-R, KS-R (P) , KS L-R, KS L-R (P) KS Vm, KS VmL KSVb, KSVb L

1 .6-2 .2 0.6-1 .6 0.6-1 .6

4-60 4-60 4-60

1 .0-2.2 1 .0-2 .2

1 2-60 20-60

Aerated concrete

0.3-0.5 0.5-0.8 0.65-0.8 0.8-0.0 0.35- 1 .0

2 4 6 8

Hbl V, Vbl, Vbl S VbI S-W

0.5-1 .4 0.5-2.0 0.5-0.8

2-8 2-1 2 2-1 2

Hbn Vbn, Vn Vm, Vmb

0.9-2.0 1 . 4-2. 4 1 .6-2.4

2-1 2 4-28 6-48

HSV HSL HHbl

1 .6-2.0 1 .2-1 .6 1 .0-1 .6

1 2-28 6-12 6-12

standard, high-precision

PB, PP

panel, high-precision panel

Ppl, PPpl

Lightweight concrete

hollow panel solid, solid with slits solid with slits and special thermal insulation properties Concrete

hollow solid facing Granulated blast-furnace slag

solid perforated hollow

Cement fibreboards

Cement fibreboards are produced from syn­ thetic and cellulose fibres, cement and water (figs B 4. 1 8 d and B 4.22 ) . They are weather­ proof, impervious to water and incombusti ble. They are available i n thicknesses from 8 to 20 mm and in sizes up to max. 1 500 x 3100 m m .

B 4.20

Perlite wallboards

Perlite wallboards have a core of cement-bond­ ed l ightweight perlite aggregate. A glass cloth plus a layer of cement on each side protect the approx. 1 1 mm thick core. These incombustible (building materials class A 1 ) , extremely robust boards are suitable for use as a render back­ ground on facades.

B 4.22 61

Bitu m i nous materials

B 5. 1

Organic sediments on the seabed and the associated carbon enrichment formed the basis for the formation of deposits of petrole­ um, natural asphalt and bitumen. High temper­ atures and pressures over m i l l ions of years transformed these substances into petroleum. I n natural deposits bitumen frequently occurs together with fine mineral inclusions in the form of natural asphalt. In the period around 3000 BC bitumen was used in Mesopotamia instead of loam as a mor­ tar for masonry. In road building asphalt was used in conjunction with clay bricks in ancient times to form highways. The Hanging Gardens of Babylon were waterproofed with layers of natural asphalt tiles, clay bricks and mortar (fi g . B 5 . 4 ) . This style of rooftop garden was popular around the Mediterranean at the time of the Renaissance, and these gardens req u i red bitu­ men to seal them.

·

Pure bitumen is worked at temperatures of 1 50220°C. After cooling, the bitumen fulfi ls its func­ tion immediately, e . g . as a seal or an adhesive. When cold, bitumen can only be used in a solution or dispersion: •

•

•

Commercially produced bitumen and

(hard paving-grade bitumen) , the residue left behind when further su bstances are volatised from straight-run bitumen by heating in a vacuum with the simultneous addition of steam. Blown bitumen is produced by blowing air and oils into molten straight-run bitumen; it exhibits greater elasticity.

A bitumen solution is made up of bitumen plus a petroleum disti llate (e.g. petrol), which undergo a curing process. A bitumen emulsion consists of a mixture of bitumen, water and an emulsifying agent; the emulsion dries slowly as the water evapo­ rates. Fillers are added to solutions and dispersions to form fi l l i n g compounds.

bitumen products

Properties

B B B B

5 . 1 Liquid bitumen 5.2 Systematic classification of bituminous binders 5.3 Physical properties of bitumen 5.4 The Hanging Gardens of Babylon, one of the first structures waterproofed with bitumen, 562 BC B 5.5 Flat roofs as an expression of technical progress, Weissenhof Estate, Stuttgart, Germany, 1 927, Ludwig Mies van der Rohe

62

The spread of the flat roof across Central Europe d uring the 1 9th century was encour­ aged by the invention of reinforced concrete and the development of framed buildings, which permitted large spans and flat roofs capable of carrying heavy loads. However, the at best only very shallow roof pitches meant that such roofs had to be sealed against the ingress of rainwater. This was achieved with a combination of bitumen and layers of paper on pressed cork boards. By the middle of the 1 9th century the industrial refining of petroleum had covered the increased demand for bitumen. I n order to obtain paraffin for lamps, refineries were establ ished, initially in America, in which petroleum was broken down through d istillation into its components with their different boiling points. One non-distil lable residue was bitu­ men, which today is sti l l obtained in the same way. We d istinguish between the following types of bitumen: Straight-run bitumen (soft bitumen) represents the non-vapourising residue. . Various grades of vacuum asphaltic bitumen •

Bitumen consists of d ifferent mixtures of vari­ ous hydrocarbons and hydrocarbon derivatives depending on the geographical location of the petroleum deposit from which it is obtained. Nevertheless, the useful properties are almost identical. They depend on the so-called colloi­ dal system - the q uantitative composition of malthenes (dispersion agent and soluble, melt­ able petroleum resins) and asphaltenes (insolu­ ble, non-meltable constituents). This results in the physical properties so typical of bitumen : a rise in temperature makes bitumen gradually softer, but the process is reversible and similar to that of a thermoplastic material. Bitumen exhi b its viscoelastic properties that range from elastic deformation to fluid ity depending on the temperature. Polymers mixed into straight-run bitumen can i nfluence these properties (poly­ mer-modified bitumen, PmB) . Bitumen has the function of a b inder. When hot and runny it wets fibres, metals and mineral materials very well and bonds them together after cooli n g . However, the action of oxygen i n the a i r a n d ultraviolet rad iation can make bitu-

Bituminous materials

Bituminous binders

Bitumen in natural asphalt

Tar and binders containing tar

Bitumen and derivatives

Rapid-curing cutback

Special bitumen

Fluxed bitumen

emulsion Cationic bitumen emulsion Polymer-modified bitumen emulsion B 5.2

men brittle on the surface and impair its adhe­ sive qual ities. Bitumen products should there­ fore be protected agai nst ultraviolet radiation by covering them in some way (e. g . chippings on flat roofs) . At room temperature bitumen exhi b its a high resistance to salts, weak acids and also strong alkalis. The d istillation of petroleum represents a physical method of production. Bitumen is non-hazardous in b iological terms and can also be used as a sealant in drinking water appl ica­ tions. Depending on its degree of purity, it can also be reprocessed and recycled. Bitumen should not be confused with pitch or tar, which have a similar appearance. Tar is obtained through the thermal cracking of coal a chemical process. These pyrolysis products contain polycyclic aromatic hydrocarbons (PAH) , and as these are carcinogenic, prod­ ucts made from pitch or tar are hardly ever used these days.

Bitumen

Paving-grade bitumen

Bitumen for use in asphalt for roadbuilding rep­ resents the largest market for bitumen. Various grades of straight-run bitumen are suitable as a b inder for minerals. The minerals used can be natural (e. g . gravel, chippings, bal last, san d ) , man-made ( e . g . slag ) , o r mineral products obtained from recycl i n g processes; their con­ tent is about 95% by weight. The asphalt required for surfaces to roads, landing strips, cycle tracks, etc. is produced in stationary mix­ ing plants. It has to satisfy high quality stand­ ards in terms of affinity to the binder, weather resistance, shock resistance and compressive strength as well as resistance to the effects of heat. The mixing grades for the asphalt are d ivided into two different types depending on the void content of the finished layer, distin­ guished accord ing to their mechanical and working properties: rolled asphalt with a no­ fines porosity (which must be compacted after

Density

Thermal conductivity

Specific heat capacity

Thermal expansion

Water absorption

[kg/m']

[W/mK]

[kJ/kgK]

[mm/mK]

H

Vapour diffusion resistance index [-]

990-1 1 00

0.1 5-0. 1 7

1 .7-1 .9

0.06

< 0. 1 %

approx. 1 00 000

laying), and mastic asphalt with a binder con­ tent greater than that of the voids. Roads usual­ ly comprise three layers: base, binder and sur­ facing. The uppermost layer can be coloured by adding inorganic pigments such as iron oxide (red) or chromium oxide (green) to indi­ cate traffic lanes.

Industrial bitumen

I ndustrial b itumen is the term used for the blown bitumen and solid bitumen used in build­ ing. Applications

The plasticity range can be adjusted by select­ ing a suitable grade of bitumen (fig . B 5.8) , and this makes bitumen ideal for protecting bu ild­ ings and structures thanks to the good bonding and adhesive properties and impermeability with respect to water vapour d iffusion. Depend­ ing on the type of construction to be sealed against i n g ress of water, we d isti nguish between roof and tunnel waterproofing , sealing of rigid or movable joints, and the sealing of tanks, basements or swimming pools. The following bituminous materials are used in building works: Sealing materials bitumen sheeting (with fleece) flexible polymer-modified bitumen sheeting ·

B

5.3

·

Roof coverings bitumen sheetin g (with fleece) corrugated bitumen sheeting asphalt shing les and tiles • •

•

Protective products undercoat (applied cold) topcoat (applied hot) adhesive compounds (applied hot) filling compounds (applied hot/cold) · ·

·

•

Coatings mastic asphalt mastic asphalt flooring asphalt tiles/blocks •

• ·

B 5. 4 63

Bituminous materials

Flexible bitumen sheeting

made from blown bitumen

Bitumen roofing felt with glass fleece base

Bitumen sheeting for waterproofing of roofs

made from polymer-modified bitumen

Bitumen waterproof sheet­ ing for felt torching

R 500 (uncoated felt 500 g/m2)

G 200 DD (glass cloth 200 g/m2)

V 50 8 4 (glass fleece 50 g/m2)

V 13 (glass fleece 50 g/m2)

PV 200 DD (polyester fleece 200 g/m2)

G 200 8 4 (glass cloth 200 g/m2)

Polymer-modified bitumen waterproof sheeting for felt torching

sheeting

G 200 8 5 (glass cloth 200 g/m2) PV 200 8 5 (polyester fleece 200 g/m2)

Insulation bituminised felt bituminised cork felt •

•

Seals jointing compounds •

Flexible waterproof sheeting made from bitumen

Flexible waterproof sheeting made from bitumen is used for sealing structures and roofs (fig. B 5.6). Such products are intended to protect struc­ tures or components against the in- g ress of water and aqueous solutions. The water in these cases occurs in various forms and has different effects, which are explained in DIN 1 8 1 95 (see "Insulating and sealing", p. 1 44).

PYE-G 200 DD (glass cloth 200 g /m2)

PYE-G 200 8 4 (glass cloth 200 g /m2)

PYP-G 200 8 4 (glass cloth 200 g/m2)

PYE-PV 200 DD (polyester fleece 200 g/m2)

PYE-G 200 8 5 (glass cloth 200 g/m2)

PYP-G 200 8 5 (glass cloth 200 g/m2)

PYE-PV 200 8 5 (polyester fleece 200 g/m2)

PYP-PV 200 8 5 (polyester fleece 200 g /m2)

Appropriate i nlays determine the mechanical properties such as strength, extensibil ity and tear resistance. G lass fleece (code letter V) is su itable for low loads, but glass cloth (G) and polyester fleece (PV) are used for h igher loads, less often jute (J) or uncoated felt (R). Metal foil (e.g. copper, aluminium) is used as an i nlay to create a vapour barrier, to prevent root penetration and also below loose soi l . Q uartz sand o r slate granules provide some protection for the flexible sheeting, talcum pow­ der and thin separating layers of polyethylene or polypropylene film ease the rolling/unrolling and working of the sheeting. Flexible sheeting made from blown bitumen has a lower resistance to ultraviolet radiation and therefore req u i res additional protection, e . g . in the form of a layer of loose gravel on flat roofs.

Flexible bitumen sheeting

Flexible bitumen sheeting consists of a backing layer (base) that is soaked in straig ht-run bitu­ men and coated both sides with a facing layer of blown bitumen. The two facing layers are responsible for the waterproofing effect and durability of the flexible sheeting.

B 5.7 64

Flexible polymer-modified bitumen sheeting

In this type of flexible sheeting the facing layers and the bitumen in which the base and inlays are soaked consist of straight-run b itumen to which a thermoplastic or elastomeric material has been added (fi g . B 5 . 7 ) . Both the thermoplastic a n d the elastomeric modification of bitumen results in a flexible sheeting with high thermal stability, good cold­ working properties and better ageing resist­ ance. The guidelines for flat roof construction do not call for a heavyweight surface protection in the form of gravel. The bitumen used for flexible polymer-modified bitumen sheeting is modified with a thermo­ plastic elastomer (styrene-butadiene-styrene, SBS) and has the code PYE. It req u i res protec­ tion against u ltraviolet radiation in the form of chippings. The bitumen in polymer-modified bitumen built­ up felt can also be modified with a thermoplas­ tic material (atactic polypropylene, aPP) - code PYP. Chippings to protect against ultraviolet

B 5.5

radiation are not required for this type of flexi­ ble sheeting. Properties

As two or more layers are employed, flexible bitumen sheetin g is regarded as more resistant to mechanical loads than flexible sheeting made from synthetic materials. However, flexi­ ble bitumen sheeting requires more care and work at junctions and details because no pre­ formed components are available for corners, penetrations and similar details. Ponding on roofs and the associated accumulation of dust and d i rt which can reduce the durabil ity of bituminous flexible sheeting should be avoided by ensurin g a minimum roof pitch of 2°. Types of flexible sheeting

In Germany the d ifferent types of flexible sheeting are distinguished by codes, e.g. PYE­ PV 200 S 5, whose meaning is as follows: •

·

•

type of bitumen used (polymer-modified bitu­ men only) , e . g . PYE type of base with weight in g/m 2 , e . g . PV 200, and in the case of metal inlays the thickness is specified as well type of sheeting and thickness in mm, e.g. S 5

Flexible bitumen sheetin g is used for water­ proofing structures and roofs. The D I N stand­ ards define the following types according to requirements: •

·

•

D I N 52 1 29 Uncoated bitumen-saturated sheeting: R 500 N D I N 52 1 43 Bitumen roofing felt with g lass fleece base: R 500, V 1 3 D I N 52 1 30 Bitumen sheeting for waterproof­ ing of roofs: G 200 DD, PV 200 DD

Bituminous materials

Bitumen grade

Needle penetration [1 / 1 0 mm]

R.a.B. softening point 2 [oC]

Fraass breaking point 3 [oC]

43-37 43-49 54-48 53-59 57-63 55 - 7 1 60-76

-15 -10 -8 -5

40 25 10

85 1 00 1 35

-20 -18 -5

50-90 50-90

48-54 48-55

-15 -15

1

Straight-run bitumen

8220 - 8 1 60 8 1 00 - B70 870- 850 845- 830 B20- 830 825 - 8 1 5 820 - 8 1 0

220-1 60 1 00 - 70 70-50 45-30 20-30 25-1 5 20- 1 0

0 3

Blown bitumen

85/40 1 00/25 1 35 / 1 0 Polymer-modified bitumen

B 5.6 Systematic classification of flexible bitumen sheeting B 5.7 Flexible polymer-modified bitumen sheeting on a substrate coated with bitumen u ndercoat B 5.8 Physical properties of various bitumen grades B 5.9 8itumen u ndercoat as waterproofing to a structure B 5.10 Jointing compound between paving stones

Pm8 65 A Pm8 65 C

elastomer-modified thermoplastic-modified

1

The needle penetration test measures how far a 1 00 g needle penetrates the bitumen (heated to 25°C) in 5 s. The determination of the softening point with ring and ball (R.a.B. method) uses a brass ring filled with bitumen that is loaded with a steel ball and heated in a water or glycerine bath. The softening point is reached when the bitumen has sagged 25.4 mm under the weight of the ball. 3 A layer of bitumen spread evenly on a sheet metal plate is deflected in a defined way. The Fraass breaking point is the temperature at which the layer of bitumen fractures or cracks during bending. 2

B 5.8 ·

·

•

•

•

D I N 52 1 31 Bitumen waterproof sheeting for felt torching: V 60 S 4, G 200 S 4, PV 200 S 5 D I N 52 1 32 Polymer-modified bitumen sheet­ ing for waterproofing of roofs: PYE-G 200 DD, PYE-PV 200 D D D I N 52 1 33 Polymer-modified bitumen water­ proof sheeting for felt torc h i n g : PYE-G 200 S 4, PYE-G 200 S 5 , PYE-PV 200 S 5, PYP-G 200 S 4 , PYP-G 200 S 5 , PYP-PV 200 S 5 DIN 1 8 1 90 Waterproof sheeting for the water­ proofing of buildings: Cu O , 1 D , AI 0,2 D D I N 1 8 1 95-2 Cold-applied self-adhesive sheetin g : KSK

Cold-applied self-adhesive flexible bitumen sheeting has a coating of adhesive on its underside so that it can be laid without the need for any heat (e.g. for supportin g construc­ tions sensitive to heat or on steep pitches) .

Further applications for bitumen

Mastic asphalt

Compared with asphalt for roadbuilding, mastic asphalt has a h igher binder content of sol id bitumen and m inerals with smaller particle sizes. Other materials can be added to modify the properties to suit different applications. Nat­ ural asphalt is frequently added to the bitumen obtained from the refinery, which increases the homogeneity, compactibi lity, deformation resistance and ageing resistance of the mastic asphalt; indeed, the b itumen can be replaced entirely by natural asphalt. As mastic asphalt is free from voids, watertight, resistant to many alkalis and acids and can be laid without joints, it is ideal as a form of waterproofin g , e . g . for wet rooms, for market halls, as protection against substances vulnerable to water, or on monolithic, uninsulated structures.

Bitumen solutions, bitumen emulsions

As undercoats, bitumen solutions and emul­ sions can form the bond between the substrate and flexible bitumen sheeting or insulating materials (fi g . B 5.9) . They form an anchorage in the m ineral substrate and bind any dust on this. Solutions and emulsions are appl ied cold . A s solvents have a low boiling point a n d are therefore volatile and can escape i nto the atmosphere d uring application, it is preferable to use a solvent-free bitumen emulsion or solu­ tion. Jointing compounds

Hot-applied jointing compounds consist of bitumen to which synthetic materials, softeners and m ineral fillers have been added. Joints in concrete, asphalt and paving can be filled with the jointing compound with its elastic or plastic variability (fig . B 5 . 1 0) . Such jointing com­ pounds prevent foreign matter collecting in the joints which m ight impair the movement of the components.

Applications

Flexible bitumen and polymer-modified bitu­ men sheeting is always used in two layers. The first of these can be bonded over the full area or just partially (spot- or strip-bonding) or fixed mechanically, but can even be laid loose. The second layer must be bonded to the first over the full area and with the joints/seams offset. An exception is horizontal waterproofin g in the case of non-hydrostatic pressure, e . g . rising damp, because in this case just one layer of uncoated bitumen-saturated sheeting i s ade­ quate. For details of laying methods and parameters in comparison to flexible sheetin g made from synthetic materials a n d rubber see "The building envelope", p. 1 25-27.

65

Wood and wood-based products

B 6. 1

Wood is readily available throughout the world and can be easily worked with simple tools. It has been used for buildings, everyday objects and furniture since the dawn of civil isation. The use of worked tree trunks in sunken-floor dwellings dating from about 20 000 BC has been proved. The embedded posts at the ends of a roughly 2 x 4 m p it supported the ridge to a couple roof which extended down to the grou n d . In the heavily forested reg ions of Europe, where softwoods grew uniformly, the log construction techniques (fig. B 6.3) stil l used today first appeared around 9000 BC. The spread of settlements to regions with fewer forests led to a more economical form of timber construction - the timber frame. Recognition of the need to protect timber against damage and decay had been taken into account by the Romans, whose perma­ nent timber structures were provided with a stone p l i nth. However, this solution was not familiar to all builders. For example, in the Middle Ages the timber houses of Danzi g (now Gdansk) h a d t o be rebuilt every 20-25 years because the timber in contact with the damp ground began to rot. On the other hand, the stave churches of Nor­ way dating from the 1 1 th to 1 3th centuries i l lustrate the durability of timber structures pro­ tected by careful detail i n g (fi g . B 6.2). Compared to structures of stone, the ind ividual components of a timber building require antici­ patory planning in order to join the individual

parts into a stable overall assembly by means of suitable joints. This is probably one of the reasons why carpenters' guilds were held in such high esteem well into the 1 9th century. I mpressive feats of carpentry such as the oak hammer-beam roof to Westminster Hall (fig. B 6.6) bear witness to their great skills. Industrialisation

Growing marginalisation caused by the new building materials steel and concrete led to efforts to rationalise the production processes and to the development of new forms of timber construction (e.g. platform frame and panel construction) . During the 1 940s Konrad Wachsmann and Waiter Gropius developed the "General Panel System" in America. This system was based on a mod ular arrangement so that walls, floors and roofs could always be assembled in the same way. It was this innovation that made it possible for five unskilled operatives to erect a house ready for its occupants - within just nine hours! Despite a declining market share, timber can still be used for building thanks to the appear­ ance of efficient wood-based products and advancements in structural engineering (fi g . B 6 . 7 ) . And since the mid-1 980s various types of timber claddings have enjoyed a comeback, regardless of the material used for the load bearing structure. The Austrian pro­ vince of Vorarlberg has taken on a pioneering role in contemporary timber architecture - more

B 6.1 Trabocco - vernacular architecture for catching fish, Fossacesia, Italy B 6.2 Stave church, Heddal, Norway, 1 2th century B 6.3 Dairy farm at the foot of the Matterhorn, Wall is, Switzerland B 6.4 The structure of a tree trunk B 6.5 Deformation of solid timber sections depending on their position with respect to the growth rings B 6.6 Westminster Hal l , London, UK, 1 399 B 6.7 Ice rink, Munich, Germany, 1 984, Ackermann + Partner B 6.8 Insurance building, Munich, Germany, 2002, Baumschlager & Eberle B 6.2 66

B 6.3

Wood and wood-based products

Rays H+f Growth ring----P-� Cambium----I-- I Sapwood-----t---- t­ Heartwood----J-H-- tHtl ----

than 20% of all new buildings in that region are built of timber.

W'7-)-1---l-\-+--Ic+-'t-+-'bl---- Pith

1---- 8ark H---- Early wood tt+-1+--- Late wood

8 6.4

· ·

•

Wood as a building material •

Every tree is an individual organism with specif­ ic characteristics. No two pieces of wood are identical. Various criteria influence q uality, appearance and potential applications: • • • •

species of tree location, macrocl imate, microclimate age of tree location within the tree structure (trunk, branch, root, heartwood , sapwood)

•

•

•

Biological structure of wood

More than 30 000 species of wood are known worldwide, and about 500 of these are availa­ ble through the international timber trade. The spectrum of tree species stretches from the eucalyptus of Australia, which reaches a height of 1 35 m, the cypresses with their 1 2 m trunk diameter, to the bristlecone pines of the USA, some of which are 5000 years old. By compari­ son, only a tiny fraction of the species available are used for building in Central Europe; figs B 6.9 and 6 . 1 0 show the most common types. The most important material properties are: •

•

good l ife cycle assessment anisotropy (dependency of most timber properties on d irection of growth) hygroscopy (moisture content is determined by ambient climate) Iow thermal conductivity coupled with good heat storage ability high strength coupled with low weight ( Ioad­ carrying abil ity) multitude of timber species with different appearances (colour, texture, odour) large range of wood and wood-based prod­ ucts available with highly developed methods of working

regenerative raw material carbon dioxide storehouse (reduction in CO 2 concentrations)

8 6.6

The fundamental b u i l d i n g blocks of wood are the cells - wood fibres. It is the job of the cells to transport nutrients, convey water and lend stability to the wood. The majority of cells have an elongated form and lie for the most part par­ allel with the trunk. The rays - running rad ially within the trunk - represent the exception; the rays store organic nutrients (fig . B 6.4) . In terms of evolution, softwoods are older and have a simpler structure, consisting primarily of one type of cell (trache i d ) . Gymnosperm con­ tain more special ised cells with specific tasks. The vessels convey the nutrients and the wood fibres form the load bearing framework for the deciduous Ang iosporm tree. Fig. B 6.4 shows the typical structure of a tree trunk. The cross-section through the trunk in

8 6.7

8 6.5

the majority of trees is as follows (from i nside to outside) : The central p ith is responsible for convey i n g water and storing nutrients in the young shoot, and this part of the trunk dies at a relatively early stage of the tree's growth. I n regions with distinct seasons, the adjoining g rowth rings map the growth of the tree in each year. Every g rowth ring consists of the light-coloured, large-pore early wood (which develops d uring the spring for transporting nutrients) and the dark, denser late wood (which determines the strength of the wood) . The cambium i s responsible for the increase in thickness. It generates wood cells on the inside and the phloem (inner bark) on the out­ side. The p h loem cells form the inner, living part of the bark, which is enclosed by the dead layers of the outer bark. The bark pro­ tects the trunk against drying out and mechan ical damage. Sap wood, heartwood and ripewood species We d ivide timber i nto sapwood, heartwood and ripewood species according to the d iffer­ ent colouration of the cross-section through the trunk. In heartwood species there is a d istinct d iffer­ ence between the colour of the heavy and hard core comprising dead wood cells, which no longer provide any transport functions, and the colour of the sapwood. The wood substances stored in the heartwood (e.g. tan­ ning agents and pigments) provide defence

8 6.8 67

Wood and wood-based products

against fung i and insects that feed on wood. Owing to its natural durability, the use of heartwood obviates the need for chemical preservatives. This group includes oak, Scots pine, chestnut and larch. The ripewood species have, l i ke sapwood, a light-coloured core and do not exh i b it any differences in colour over the trunk cross-sec­ tion . However, the core is considera b ly drier and its properties tend to resemble those of the heartwood species. The ripewood spe­ cies include beech, spruce, fir and lime.

ness or suitabil ity for impregnation can be derived from this. The density is determi ned taking i nto account the moisture content (mass and vol ume changes due to swel l i n g and shrinkage) plus the position of the wood within the trunk. The mean density for softwoods used for load­ bearing purposes l ies between 450 and 600 kg 1m3. However, this can reach 700 kg / m3 among some European hardwoods and even 1 000 kg / m3 for hardwoods imported from over­ seas.

Anisotropy A substance is designated anisotropic (Greek: anisos unequal + tropos turn) when its properties vary with direction. G lass and metal, for example, are isotropic - they exhibit the same properties in all directions. The ani sot­ ropy of wood is due to the wood fibres that run parallel to the direction of g rowth of trunk and branches, and is revealed in the various sections through the wood (transverse, radial and tangential) (fi g . B 6.4) . For example, the swelling and shrinkage of spruce in the tan­ gential d i rection is more than 25 times greater than that in the longitudinal d i rection . The permissible stresses are also considerably influenced by the grain direction. For exam­ ple, spruce can accommodate tensile stress­ es of up to 1 0 N / m m2 parallel to the grain , but perpendicular to the grain only 0.04 N / m m2 (see DIN 1 052) .

Moisture content Wood can absorb a considerable quantity of water within its cellular structure . The moisture content (Um) in the living tree can reach 70% by mass. Among the species of wood that are used for building, the fibre saturation point is reached at Um 30-35%. Above this figure, the cell cavities fi l l with so-called free moisture, but there are practically no more changes in the form d ue to swelling and shrinkage. The mean moisture content of the wood is usually meas­ ured with an electric moisture content instru­ ment. The moisture content is expressed as a mass-based percentage of the water in the wood related to the mass of the wood in the oven-dry condition . According to the new edition of D I N 4074, the moisture content of timber to be i ncorporated i n a building should not exceed 20%. For timber housebuilding the limit is 1 8% , and in g lued components 1 5% . However, t h e absorption o f water takes place not only in liquid form. Due to its hygroscopic nature, wood exchanges moisture with the sur­ rounding air. The so-called equilibrium mois­ ture content is established in timber in use as follows:

=

=

Chemical composition

The main chemical constituents of wood are: • • • •

40-50% cellulose 20-30% hemicellulose 20-30% lignin up to 1 0% other substances and ash

Physical properties

The special physical properties of wood ena­ ble it to be used for a whole range of applica­ tions in the construction industry. However, the proper use of wood presupposes a knowl­ edge about its specific characteristics, suita­ ble species and forms of construction. Density This is understood to be the ratio of the mass to the volume i nc l uding all voids (see "Physi­ cal parameters of mateials", p. 264 ) . Density is one of the most important physical para­ meters of wood because fundamental tech­ nological properties such as strength, hard-

68

• • • •

decreasing moisture content decreasing temperature decreasing grain-load angle i ncreasing density

=

•

With an annual increase of about 7 b i l l ion tonnes, cellulose is the most prolific natural substance on the p lanet. It g uarantees the tensile strength of the wood . Hemicellulose acts as a filler and cement that improves the compressive strength. In contrast to cellulose, lignin is inflexible; it provides the cell walls with the necessary rigidity and compressive strength.

depend on the respective species, the g rowth parameters (density, width of growth rings, pro­ portion of knots), the moisture content, the duration of the load action and the angle between applied load and d i rection of grain . Owing to its anisotropic characteristics, timber parallel to the grain exhibits good structural properties. When subjected to tension, timber generally exhi b its a brittle behaviour, but com­ pressive or flexural stresses usually cause plastic deformations prior to failure. The tensile strength is roughly twice the compressive strength. Generally, the strength of timber increases under the following conditions:

•

· •

heated structures enclosed on all sides 9 ± 3% unheated structures enclosed on all sides 1 2 ± 3% roofed structures open on all sides 1 5 ± 3% constructions exposed to the weather on all sides 1 8 ± 6%

Wood's ability to absorb and release moisture can make a major contribution to improvin g the interior climate. However, the swel l i n g and shrinkage leads to d imensional fluctuations. Fig. B 6.5 shows the deformations of solid tim­ ber sections depending on their position rela­ tive to the growth rings and their original loca­ tion within the cross-section. As far as possi ble, timber components should be incorporated i n a structure with the moisture content to be expected in the final condition long-term. This is a prime req u i rement if chemical preserva­ tives are to be avoided. Strength The strength of a building material is defined as its resistance to fai lure. Timber exhibits a wide range of elastomechanical properties that

A high proportion of knots d isrupts the grain and results in a lower strength. I ndeed, in very knotty Scots p ine the tensile strength can be reduced by up to 85% . The structural proper­ ties also decrease over time in the case of high long-term loads. For example, the bending strength of spruce subjected to a permanent load is only approx. 60% of its short-term strength. As wood exhibits individual character­ istics that experience severe fluctuations, the permissible strength values are set very low for safety reasons. In the end this leads to distinct­ ly oversized cross-sections. The individual load-carrying capacity of a timber member can be determined these days using non-destruc­ tive techniques (see p. 70) , which results in considerably more slender components. Thermal properties The porosity of wood gives it good thermal insulation properties plus pleasant surface tem­ peratures. The thermal conductivity of softwood is about 0 . 1 3 W/mK, that of hardwood about 0.20 W/mK. The thermal conductivity depends on d i rection of grain, density and moisture con­ tent; parallel to the grain it is about twice that perpendicular to the grain. The good specific heat storage capacity of wood ( 1 .67 kJ/kgK for a moisture content of 1 5%) can help to improve the interior c l imate. Compared to many other building materials, the coefficient of thermal expansion is extreme­ ly low. According to D I N 1 052 it is therefore not usually necessary to check changes in length due to temperature fluctuations.

Wood and wood-based products

Species of wood

There exists an enormous diversity of species and each has its own specific serviceabi l ity features, appearance and potential appl ica­ tions. Aesthetic considerations and preserva­ tion aspects must be harmonised when choos­ ing a type of wood. Fig. B 6. 1 1 l ists the properties and features of the timbers used in building. Owing to their faster growth , softwoods are usually more cost­ effective than hardwoods. In recent years more and more softwoods imported from abroad have been used for build i n g . Their advantages over European species are that they are straighter and longer, less vulnerable to rot and have fewer knots. Non-European hardwoods are employed for specific purposes internally and externally, or as exotic, attractive veneers. However, the energy required for their transport considerably worsens their l ife cycle assess­ ments.

a

Tree-felling and the processing of structural solid timber products

Felling trees in winter is advantageous owing to the lower external temperatures, which limits the number of pests, and the reduced risk to the wood outside the sap period. However, the increasing demand for timber means that the winter felling very common in the past is some­ times no longer adequate these days. Depend­ ing on the stock of trees, fast-growing soft­ woods, e . g . spruce and fir, are ready for fel l i n g after 60-1 20 years, oak a n d beech after about 80-1 40 years.

e

Conversion and drying

Various types of conversion - depending on the later use of the wood - are employed to obtain sawn timber from the cross-section of the tree trunk (fig . B 6. 1 3) : •

One-piece conversion The complete retention of the heart (i.e. pith) results in a high risk of crackin g during dry­ ing, and such timber is recommended for low­ grade applications only.

B 6.9 Softwoods (abbreviations to D I N 4076) a Douglas fir (DGA) b Spruce (FI) c Scots pine (KI) d European larch (LA) e Pine (PIP) f Fir (TA) 9 Western hemlock (HEM) h Western red cedar (RCW) B 6. 10 Hardwoods (abbreviations to D I N 4076) a Maple (AH) b Ekki (azobe) (AZO) c Beech (European beech) (BU) d Oak (El) e Dark red meranti (MER) f Merbau (MEB) 9 Robinia (ROB) h Teak (TEK) e

9

h

8 6. 1 0 69

Wood and wood-based products

Species

Density 1

Compr. strength parallel to grain

Tensile strength parallel to grain

Thermal conductivity 2

Heat storage index

Vapour diffusion resistance index 3

[kg/m3]

[N/mm"l

[N/mm"l

[W/mK]

[kJ/m3K]

DGA FI KI LA PIP TA HEM RCW

51 0-580 430-470 51 0-550 540-620 51 0-690 430-480 460-500 360-390

42-68 43-50 55 55 4 1 -58 47 36-55 29-35

82-105 90 1 04 1 07 1 05 84 68 80-93

0.12 0.09-0 . 1 2 0 . 1 2-0. 1 4 0 . 1 1 -0. 1 3 n.a. 0 . 1 0-0. 1 3 n.a. 0.09

AH AZO BU El MER MEB ROB TEK

61 0-660 1 020-1 1 20 700-790 650-760 540-760 81 0-900 740-800 590-700

58-62 87-108 62 65 5 1 -65 59-82 58-72 52-60

82-100 1 50-2 1 5 1 35 90 1 20-165 1 40 1 20-148 117

0. 1 5 n.a. 0.1 5-0. 1 7 0. 1 3-0.21 n.a. n.a. n.a. 0.1 6-0. 1 8

Abbreviation to DIN 4076

Swelling and shrinkage behaviour tangential [% per 1 % change in moisture ct.]

Resistance of heartwood to fungal attack

Resistance of heartwood to insect attack

H

Swelling and shrinkage behaviour radial [% per 1 % change in moisture ct.]

[class 1 -5]

[class 1 -5]

660-750 560-6 1 0 660-720 700-81 0 660-900 560-620 600-650 470-5 1 0

n.a. 88 68 302 n.a. n.a. n.a. n.a.

0.1 5-0. 1 9 0.1 6-0. 1 9 0.1 6-0. 1 9 0.14 0.18 0 . 1 2-0. 1 6 0.1 1 -0. 1 3 0.07-0.09

0.24-0.31 0.29-0.36 0.29-0.36 0.29-0.3 0.29-0.33 0.28-0.35 0.24-0.25 0.20-0.24

3 2 2-3 3 3 2 2 5

3 2 2 4 2-3 2 2 4

790-860 1 330-1460 9 1 0-1 030 850-990 700-990 1 050-1 1 70 960-1040 770-9 1 0

71 n.a. 86 1 40 n.a. n.a. n.a. n.a.

0 . 1 0-0.20 0.30-0.32 0.1 9-0.22 0.1 8-0.22 0. 1 4-0. 1 8 0. 1 3 0.1 7-0.24 0.1 3-0. 1 5

0.22-0.30 0.4 0.38-0.44 0.28-0.35 0.29-0.34 0.26 0.32-0.38 0.24-0.29

1 5

1 5 2 4 3-4 4-5 4 5

Softwoods

Douglas fir Spruce Scots pine European larch Pine Fir Western hemlock Western red cedar Hardwoods

Maple Ekki (azobe) Beech (European) Oak Dark red meranti Merbau Robinia Teak

4 4 5 4 5

1 The

figures here are valid for a mean moisture content of 1 5%. Values for structural timber to EN 1 2524: density 500 kg/m3 0. 1 3; 700 kg/m3 = 0.20; intermediate values may be interpolated. 3 Owing to the numerous dependencies, ARGE Holz (German Timber Organisation) recommends assuming a simplified guide value of 40 for the species of wood given here; EN 1 2524 prescribes the following for structural timber depending on the density: 500 kg/m3 = 20/50; 700 kg/m3 = 50/200. 2

=

B 6. 1 1

. Two-piece spl it-heart conversion This form of conversion reduces the risk of cracking, distortion and twisting. Two- and four-piece conversion, without heart For pieces of timber that must satisfy higher standards of appearance, the heart plank is removed to reduce the risk of cracking even further. •

board req u i res about 1 6 hours to lower the moisture content from 30 to 8%. Grading, surface finishing a n d gluing

Even today, some sawn timber and round tim­ ber sections are allowed to dry in the open air. Depending on the time of year and the prevail­ ing climate, 25 mm spruce boards can take about 60-200 days and the same boards in oak 1 00-300 days to reach a mean moisture content of 20% . The kiln-drying of higher-grade solid timber products takes place under controlled climatic conditions in closed chambers. At a drying temperature of up to 90°C, a 30 mm spruce

The growing conditions and the local c l imate lead to great d ifferences in the structure of wood which are revealed in its properties and its appearance. Strength g rading is prescribed for load bearing and bracing timber members. We distinguish between visual and machine grading. Visual strength grading is based on the external features (e. g . knots, width of growth rings), which permit a conclusion to be reached on the basis of the D I N 4074-1 classification . I n mac h i ne strength g rading the measurement of certain material properties (e.g. modulus of elasticity, density, moisture content) enables higher grading classes to be achieved. Furthermore, there are various criteria for grad­ ing timber according to its aesthetic impres-

a

c

70

b

d

sion. This assessment i s based o n other fea­ tures to those important for strength grading and can be used for non-load bearing members as wel l as an add itional criterion for structural timber. The grad ing required by the authorities is therefore compulsory. As a rule, squared sections, boards and planks are supplied and assembled in the rough-sawn condition. In the case of exposed timber mem­ bers, planed surfaces or special edge work (sharp edge, chamfered) must be contractually agreed beforehand. The gluing of loadbearing sol id timber products (figs B 6. 1 2 c to f) can only be carried out with approved adhesives. Urea-formaldehyde, mod­ ified melamine and phenol-resorcinol resins all contain formaldehyde, but the concentrations lie wel l below permissible limits for this sub-

e

B 6.12

Wood and wood-based products

stance owing to the very small proportion of joints in solid timber products. Adhesives made from polyurethane are free from formaldehyde. The preferred method of achieving structural longitudinal spl ices these days is to use finger joints. Wedge-shaped incisions are made in the end grain of the solid sections to be joined and the pieces are pressed together after spread­ ing adhesive on the joint faces. In glued laminated timber (glulam) the adhesive is spread over the surface of the timber. The use of transparent adhesives and joint thick­ nesses of approx. 0.1 mm result in the i nd ividu­ al laminations of g lulam products being hard ly perceptible. Fissures

Lightning and frost shakes, which occur on the living tree, are not permitted in timber for load­ bearing purposes. By contrast, D I N 4074 expressly permits shrinkage splits that occur during the drying phase. The conversion of the timber, the careful drying and the adaptation of the moisture content during assembly to the climate of the location of use can reduce the likelihood of fissures. However, fissures can never be completely ruled out even with a care­ ful choice of material and correct workmanship.

Wood a n d wood-based products

The industrialisation of the woodworking indus­ try led to the development of many new solid timber products and wood-based products. A selection of the most common solid timber products together with details of their signifi­ cant features is g iven below. Solid timber products

Structural solid timber products involve at most very little change to the structure of the wood. The processing is based - depending on the particular product - on sawing, drying, grad­ ing, finger-jointing and applying adhesive to the surface. Sol i d timber products used for loadbearing or bracing purposes must be approved by the building authorities. Round sections These can be simply trunks with the branches and bark removed (fi g . B 6. 1 2 a) . Relieving grooves are often cut i n larger cross-sections to reduce the risk of uncontrolled crackin g . The surface fin ish can range from retaining the orig­ inal trunk form, to the evening-out of irregulari­ ties, to the machining to size with a constant diameter and smooth surface. Round sections are primarily used for the load bearin g mem­ bers of frames, but also in landscaping work and timber engineering projects. Sawn solid timber made from softwood and hardwood Sawn solid sections (fig. B 6 . 1 2b) are produced by cutting the debarked trunk into square or more usually - rectangular sections. Depend-

ing of the ratio of width (b) to thickness (d) or depth ( h ) , we classify the resulting sections as sawn sections, planks, boards or battens: sawn sections: b $; h $; 3 b and b > 40 mm planks: d > 40 mm and b > 3 d boards: d $; 40 mm and b � 80 mm battens: d $; 40 mm and b < 80 mm •

·

•

•

One-piece conversion

Drying, finger-jointin g , planing, chamfering and further profiling are the operations involved in the processing of sawn sol id timber sections. Such sections are used in many ways in the building industry, e . g . as load bearing mem­ bers, supporting constructions, formwork or external cladding. Solid structural timber (KVH®) These are members made from better-quality sawn softwood products (fi g . B 6. 1 2 c) . The k i l n-drying to a moisture content of 1 5±3%, the careful conversion and the visual strength grading with additional grading req u i rements help ensure a high degree of d i mensional sta­ bility, low risk of fissures and a high-quality sur­ face finish. The trade offers solid structural tim­ ber for exposed and normal purposes. Owin g t o their good d imensional stability, these prod­ ucts are ideal for timber housebuilding and for load bearing members. The low moisture con­ tent enables these products to be used without chemical timber preservatives even in fully i nsulated constructions. Four-piece beams The characteristic feature of the four-piece beam is the central "conduit" running the full length of the timber (fi g . B 6. 1 2 d ) . These prod­ ucts are manufactured by g l u i n g together four softwood squared or similar segments with the grain parallel and the wane placed on the inside. The polyurethane adhesive used forms a structural joint. The moisture content of < 1 5% means that these beams can be used for simi­ lar applications to the sol id structural timber described above. Duo and trio beams These products are made from two or three planks or sawn sections whose surfaces are glued together (fi g . B 6. 1 2 e) . Drying the timber to achieve a moisture content of < 1 5% is fol­ lowed by visual strength grading, finger-joint­ i n g , planing on all sides and cutting to length before the adhesive is appl ied to join the selected pieces to form a beam. Afterwards, the d uo/trio beam can be planed again as a whole and the arrises chamfered. This high­ quality soli d timber product represents another alternative to the aforementioned sol id structur­ al timber and four-piece beam.

Split-heart two-piece conversion

Two-piece conversion, without heart

Four-piece conversion, without heart 8 6. 1 3 8 6. 1 1

Physical parameters of common species of wood 8 6 . 1 2 Solid timber products for structural purposes a Round section b Solid section (VH) c Solid structural timber (KVH®) d Four-piece beam e D uo/trio beam f Glued laminated timber 8 6. 1 3 Forms of conversion 8 6. 1 4 Linear wood-based products a Structural veneer lumber (SVL) b Parallel strand lumber (PSL)

Glued laminated timber (glulam) G l u lam sections consist of at least three soft­ wood boards (laminations) glued together with their grain paral lel. They are manufactured in a similar way to the d uo/trio beams, but in this case the moisture content is only about 1 2% a

b

8 6. 1 4 71

Wood and wood-based products

Wood-based products

Solid timber

Splitting

Debarking LOg S

�1 LI

L__________

Sawing

Sawing

Rotary cutting

Planing

Chipping

I

I

I

I

Sh in g l es __________�

Standard shingles Decorative shingles

ve n ee rs

�1 1

__________� L-

__________� L_____ _ ____ L-

Sawn sections Planks Boards Battens

Solid wood boards

Veneer plywood

Plywood

Laminated veneer lumber

Multi-ply board

Solid structural timber

Blockboard Laminboard

Parallel strand lumber

Four-piece beam

Wood wool

Wood wool slab Multi-ply l ightweight building board

11

11

Chips

Glued laminated timber

Wood cement particleboard

Bitumen-impregnated wood fibre insulating board Wood fibre insulating board Medium board Hardboard

Extruded particleboard

Medium density fi breboard

Tubular particleboard

Plasterboard Fibre-cement board

Oriented strand board Laminated strand lumber

and during the strength grad ing any larger growth-related defects are eliminated. Further­ more, besides straight members it is also possible to produce elements with a variable cross- section, or with single or double curva­ ture. G lued laminated timber is ideal for heavily loaded, long-span members ( e . g . single-storey sheds, bridges) and for components that must satisfy high demands i n terms of dimensional stability and appearance. The life cycle assessment for g lued laminated timber suffers due to the additional energy requirements during production and the use of adhesives. This is also true for other processed timber products. Wood-based products

These products - in the form of fibre boards and particleboards - have been used in the building industry for more than 50 years. In the meantime, the industry has developed a whole range of products (fig. B 6. 1 5) . The appear­ ance of further products capable of accommo­ dating high stresses can be expected in the near future. Wood-based products consist of small pieces of wood, mostly pressed together with the help

of adhesives or mineral b i nders to form boards or l i near members. The raw materials for boards, l i near members, veneers, chips and fibres stem from the sawm i l l , industrial waste and other scrap wood, provided it is free from foreign matter. The production process results in a homogeneity that leads to material properties with a low scatter. In comparison to solid timber products, the anisotropy of the wood is evened out to a large extent, and the swelling and shrinkage tendencies are considerably reduced. Wood-based products made from veneers or boards ( i . e . layered products made up of plies of material) usually achieve higher strengths. Boards made from chips or fibres on the other hand are not as strong as mature timber. If wood-based products are to be used for load­ bearing purposes, then they must be approved by the building authorities. D I N 68 800 parts 2 and 3 d ivide such boards into three classes depending on their resistance to moisture. These classes correspond to conventional usage situations and the anticipated maximum moisture contents that can occur, which may not be exceeded:

Production sizes of wood-based boards

B 6 . 1 5 Systematic classification of solid timber and wood·based products B 6 . 1 6 Formats and material thicknesses of wood·based products (guide only) B 6.1 7 Physical parameters of solid timber products and linear wood· based products B 6 . 1 8 Board·type wood·based products a 3·ply core plywood b Laminated veneer lumber (LVL) C BUilding-grade veneer plywood d BUilding·grade veneer plywood of beech (BFU·BU) e Particle board (P) f Oriented strand board (OSB) g Laminated strand lumber (LSL) h Medium density fibreboard (MDF)

Fibres

Porous softboard

Particleboard

Thin particleboard

Lightweight particle- Gypsum-bonded board with wood particle board wool facing Chipboard with fibre facing

Duo/trio beam

Defibration

Abbre­ viation

·

•

·

B 6. 1 5

HWS class 2 0 : max. moisture content 1 5% (e.g. inner linings to external walls) HWS class 1 00: max. moisture content 1 8% (e.g. cladding to external walls and voids) HWS class 1 00 G: max. moisture content 21 % (e.g. backing layers beneath waterproofing on fl at roofs)

The binder used for wood-based products bonded with synthetic resin can make use of various organic adhesives (urea, melamine, phenol ic and other resins) . Boards of class 1 00 G are impregnated with an approved tim­ ber preservative to combat fungi that feed on wood . Wood-based products bonded with gypsum can be used for applications of class 20 and 1 00, those bonded with cement for class 1 00 G as well (see "Bu i l d i n g materials with m ineral binders", p . 61 ) . Fig . B 6. 1 6 lists the usual material thicknesses and maximum dimensions for common wood­ based products. 3- and 5-ply core plywood

These boards consist of three or five cross­ banded (i.e. adjoining p l ies at 90° to each other) softwood plies (4-50 mm thick) g lued

min. material thickness [mm]

max. material thickness [mm]

max. width [mm]

max. length [mm]

75 75 25 40 280

3000 1 820 1 525 1 850 483

6000 23 000 3000 3050 20 000

Layered products

Multi·ply board Laminated veneer lumber Veneer plywood Building-grade veneer plywood Parallel strand lumber

FSH FU BFU PSL

12 27 8 10 44

LSL OSB P

32 6 2,8

89 40 38

2438 2620 2050

1 0 700 5000 5300

MDF

6

25

1 250

2500

Particleboards

Laminated strand lumber Oriented strand board Chipboard Fibreboards

Medium density fibreboard .

B 6. 1 6 72

Wood and wood-based products

together (fi g . B 6. 1 8 a) . The strengths of such boards vary considerably depending on the respective ply thickness, the species and the quality of the wood. Three- and five-ply core plywood is suitable for load bearing and brac­ ing purposes. Cross-laminated timber Like the three- and five-ply core plywood described above, these boards also consist of cross-banded softwood plies glued together. The individual p lies are glued together to form wall, roof or floor panels with a thickness of up to 85 mm. Computer-controlled assembly plants render possi ble the prefabrication of window and door openings at the works with millimetre precision (figs B 6 . 2 1 and 6.22) . Laminated veneer lumber (LVL) Softwood rotary-cut veneers approx. 3 mm thick can be pressed together and g lued with phenolic resin to form a very efficient wood­ based product (fig. B. 6. 1 8 b) . In grade S (for linear members) the d i rection of grain l ies par­ allel in all pl ies, whereas in grade Q (for planar members) the direction of grain i n some plies lies transverse to the adjoining pl ies.

Structural veneer lumber (SVL) products are linear components with a maximum width of 500 mm that are made from several LVL ele­ ments glued together (fig . B 6. 1 4 a) . These products can be used as beams, columns, facade constructions or in timber housebuild­ ing. Parallel strand lumber (PSL) PSL represents an alternative to solid timber products (e.g. g lued laminated timber) for heavily loaded, linear components (fig. B 6. 1 4 b) . The manufacture o f parallel strand lumber requires strips of rotary-cut veneer 25 mm wide x 0.5-2.6 m long in Douglas fir (OF) or southern yellow pine (SYP) which are aligned with the axis of the beam and g lued together with phe­ nolic resin.

Solid timber products and linear wood-based products

Building-grade veneer plywood (BFU) The term veneer plywood covers boards made from several veneer plies g lued together (fi g . B 6. 1 8 c), but with five p lies or more and thick­ nesses exceeding 1 2 mm the term multiplex is often used. Owin g to their high strength, such boards are ideal for load bearing components. If cross-banded beech veneer i s used instead of softwood (grade B U ) , this produces a very high qual ity, stable board suitable for internal fitting-out and furniture (fi g . B 6. 1 8d ) . Moulded plywood It is also possible to create many different shapes by pressing multi-ply g lued veneer ply­ wood over a negative mould under steam. This technique is mainly used for internal fitting-out and furniture applications. Blackboard (S7) and laminboard (STAE) The core in blockboard and laminboard con­ sists of timber stri ps. In blockboard the strips are 24-30 mm wide, in laminboard < 8 mm. Veneer facings are glued to both sides of the core. In grade 1 even the strips are g lued together without flaws, grade 2 boards can have small flaws here. Particleboards Particleboards are widely used, e . g . as plank­ ing to provide stability, or as a covering to walls and floors. The dense surface is ideal as a backing for veneers and other finishes. We distinguish between particleboards bonded with synthetic resin and those with a mineral binder. The manufacturing process influences the posi­ tion of the chips in the board and hence also the stability of the final product. Pressed parti­ cleboards contain horizontal chips, but i n extruded boards the c h i ps are arranged per­ pend icular to the board.

d

Particleboards (P) consist of relatively small c h i ps lying parallel with the plane of the board and these days are very widely used for inter­ nal fitting-out and furniture (fig . B 6. 1 8 e) . Parti­ cleboards bonded with synthetic resins make use of phenolic, urea or modified melamine resins. Such boards are available in thickness­ es from 2.8 to 38 mm. Vapour diffusion resistance index

Density

Compress. strength parallel to grain

Tensile strength parallel to grain

Tensile bending strength

[kg / m"]

[N / mm']

[N/ mm']

[N / mm']

Swelling and shrinkage behaviour [% per 1 % change in moisture]

420 420 420-460 420-460 420-560

8.5 8.5 8.5-1 1 8.5 8.5 -1 3

7 7-9 7 8.5-13

10 10 1 0-1 3 10 1 1-18

0.24 0.24 0.24 0.24 0.24

40 40 40 40 40

480-550 600-700

16 20

16 18

1 7-20 1 9-21

0.01 /0.32 ' 0.01 /0.32 '

60/80 50/ 1 00

[-]

Solid timber products (e.g. spruce)

Sawn section; S1 0 Solid structural timber (KVH®) Four-piece beam Duoltrio beam Glued laminated timber

7

Linear wood-based products

Laminated veneer lumber grade S Parallel strand lumber (PSL) 1

In the direction of the board parallel to the grain/perpendicular to the grain. B 6. 1 7

h

B 6. 1 8 73

Wood and wood-based products

Board-type wood-based product

Vapour diffusion resistance index

Permissible compressive strength in plane of board 1 [N / m m2]

Thermal conductivity

Shrinkage in plane of board

[kg / m3]

Permissible bending stress perpendicular to plane of board 1 [N / mm2]

[W/ m K]

[% per 1 % change in moisture cont.]

FSH BFU ST, STAE

400-500 400-500 400-800 400-800 450-800

4.4-22 3.5-1 3 1 3-21 13 n.a.

5.5-1 1 7.5-1 1 8-1 9 4-8 n.a.

0.1 4 0.14 0.15 0. 1 5 0. 1 5

0.02 0.02 0.02 0.02 0.02

50/400 50/400 50/400 50/400 50/400

D-s2dO D-s2dO D-s2dO D-s2dO D-s2dO

P OSB LSL

550-700 600-660 670-700

2-4 .5 2.5-8 1 6-20

1 .75-3 1 -4.2 8-1 0

0.13 0. 1 3 0. 1 4

0.035 0.035 0.3-0.4

50/ 1 00 50/ 1 00 50/ 1 00

D-s2dO D-s2dO D-s2dO

MDF HB MBL/MBH SB SB.H/SB.E

450-750 900-1 000 400-900 230-400 200-350

3.6-8.0 6-8 2.5-5 0.8-1 .3 0.8-1 .3

2.8-4.5 4 1 .5-2 . 1

0. 1 -0. 1 7 0. 1 7 0.08-0. 1 7 0.04-0.07 0.056-0.06

0.2 0.2 0.2 n.a. n .a.

8/70 70 8/70 5/10 5/10

D-s2dO D-s2dO E to D-s2dO E E

Abbreviation

Density

Combust2 ibility class

[-]

Layered prpducts

3-ply core plywood 5-ply core plywood Laminated veneer lumber Building-grade veneer plywood Blockboard, laminboard Particleboards

Chipboard Oriented strand board Laminated strand lumber Fibreboards

Medium density fibreboard Hardboard Medium board Porous softboard Bitumen-impregnated woodfibre insul. bd. 1 2

Based on information provided by manufacturers. European combustibility class to DIN EN 1 3501 with the exception of floor coverings. This corresponds to D I N 4 1 02 building materials class B2.

A s the chips of extruded boards are arranged perpendicular to the plane of the board, such boards have high transverse tensile strengths but low tensile bending strengths. Therefore, they are usually installed with planking to both sides (e.g. thin particleboards) . We d istinguish between solid extruded particle­ board (ES) and tubular particleboard (ET) , in which internal longitudinal voids reduce the self-weight of the board . Extruded boards are often used for door leaves or in partitions. Oriented strand board (OS8) Chips (approx. 75 mm long) aligned parallel with the surface of the board give oriented strand board its characteristic appearance (fig . B 6. 1 8 f) , which can remain visi ble as a vigorously textured surface under thin coatings. The edges are vulnerable to damage and OSB is therefore not suitable for exposed areas. Owing to the alig nment of the chips, OSB has a distinctly higher tensile bending strength in the longitudinal d i rection than in the transverse d i rection. This wood-based product is suitable for load-sharing and bracing planking as well as for load bearing flooring beneath a floor covering. Laminated strand lumber (LSL) Chips of poplar approx. 300 mm long are pressed together with the add ition of MDI poly­ urethane adhesive. Laminated strand lumber (fig . B 6 . 1 8 g) exhibits h i g h strengths and is therefore suitable for applications involving high loads. Wood fibreboards Wood fibreboards are manufactured without any b inder - simply by pressing the fine wood fibres together which, owin g to the high pres-

74

sures used, undergo felting (interlockin g ) . The strength of these boards varies depending on the degree of compression. The ensuing fully homogeneous material no longer exhibits any texture (e.g. grain) . In contrast to other wood­ based products, wood fibreboards can be processed like solid timber by routing or similar machining processes to form three-dimensional components. Medium boards (MBLlMBH) and hardboards (HB) are pressed together using the wet proc­ ess without the need for any binder. Their hard­ wearing surfaces protect them against mechanical damage. Owing to their low density and good sound absorption properties, porous fibreboards (SB) and wood fibre insulating boards (WF) are suit­ able for use as combined thermal and sound insulation (see " I nsulating and sealing", p. 1 38) . The manufacture of medium density fibreboard (MDF, fig . B 6. 1 8 h) involves adding a small amount of urea or phenol ic resin to the wood fibres prior to pressi n g . Thanks to their hard , abrasion-resistant surfaces, medium density fibreboards are used as backings for all kinds of finishes and are consequently ideal for i nter­ nal fitting-out. It is also possible to colour the boards evenly by adding pigments; however, the colour range currently available is limited to yellow, red , green , blue and black. These boards can also be shaped with the help of templates under the action of pressure, heat and moisture. Veneers

Almost all the boards and panels made from wood-based products are suitable as backings

B 6. 1 9

for veneer. Consequently, the fitting-out and furniture industries have materials at their dis­ posable that are less vulnerable to shrinkage and cracking than the equivalent solid timber products, but sti l l achieve a simi lar visual effect. This allows more economical usage of high-qual ity species of wood. As traces of wear and damage become readily noticeable along the edges, veneered boards are usually provid­ ed with a solid wood strip to protect the edges. We d istinguish between veneers for plywood, veneers used as backings and those for deco­ rative purposes. Sawn veneers Owing to their production with a circular or gang saw, sawn veneers are at least 1 mm thick, and the high wastage makes them com­ paratively expensive. They can be produced free from fissures and while retaining their natu­ ral colour and grain . Sliced veneers The veneer is sliced lengthwise across the full width of the wood when particularly high-qual ity surfaces are required. The angle of application of the blade influences the final appearance. The wood for this process has to be usually steamed or cooked, which changes the appearance of especially l i ght-coloured wood species such as maple and birch. The use of graded strips of veneer in a mirrored arrangement enables symmetrical veneer pat­ terns or the illusion of greater width. Rotary-cut veneers Rotary-cut veneers are obtai ned by cutting the trunk as it rotates. This creates an endless rib­ bon of veneer material. Rotary-cut veneers are less expensive than sawn and sliced veneers,

Wood and wood-based products

but for most species of wood result in an unnat­ ural, "turbulent" grain. They are used for pro­ ducing laminated veneer lumber or for backing veneers. Rotary-cut face veneers can be obtained from birch, ash and maple provided the trunk is cut at an angle. This results in a similar grain to the sliced veneers but with a greater spacing between the g rowth rings.

Protecting wood

As a regenerative raw material, wood forms part of the natural process of decomposition into its original constituents and their return to the biogenic lifecycle. The purpose of passive and chemical protection of the wood is to guar­ antee the durability of the material and protect the wood against degradation by organisms (fungi and insects) that feed on (and thus destroy) the wood. Fungi extract cellulose and lignin from the wood and therefore cause rot­ ting and decay. They tend to g row when the moisture content exceeds 20% and the cell cavities contain free moisture. I nsects can attack the wood and eat through the softer sap­ wood, which is rich in proteins. The primary objective of so-called passive protection of the timber is to minimise the conditions under which such damaging organisms can thrive. Protection against fung i is therefore mainly aimed at limiting the moisture content of the timber. Such measures include, for example, providing overhanging eaves and protectin g plinths against splashing water. Furthermore, choosing a durable species of wood can elimi­ nate the need for chemical treatments (fi g . B 6. 1 1 ) . All the passive measures should certain­ ly be investigated before resorting to chemical preservatives. Chemical wood preservatives are based on the use of pesticides. The preservative must pene­ trate as deep as possible. We d istinguish between preservatives soluble in water and those containing solvents (see "Surfaces and coatings", p. 1 98 ) . I n recent years environmen­ tally compatible preservatives have appeared on the market alongside those that cause hygiene and ecology concerns. The new pre­ servatives include, for example, boron salts, which can penetrate deep into the timber cross-section when appl ied using pressure impregnation.

as fuel, the other half for paper production and building. Consequently, the forest is one of the largest and, at the same time, most inexpen­ sive producers of raw materials. From forest management to the Brundtland Report

Up until the 1 8th century carpenters them­ selves searched for suitable trees in the forest, felled them and worked them as required . Only as wood became scarcer did this tradition change to planned forest management. Since 1 7 1 3 wood has been used according to the sustainabil ity principle first devised by the Ger­ man forester Hans Car I von Carlowitz. At the start of the 1 8th century sustainabil ity meant that no more wood could be taken from the for­ est than could be regrown. This concept, initial­ ly i ntended for forestry management, was taken on board by the World Commission on Environ­ ment and Development (Brundtland Report) i n 1 987 a s a basis for a n integrative global policy strategy. Wood as a carbon storehouse

Biomass (wood ) is formed from the carbon d ioxide (C02) in the air, water ( HP) and trace elements from the soil with the help of chloro­ phyll and solar energy. During this process oxygen (02) is released. When it is burned, but also during natural de­ gradation by fungi and bacteria, the b iomass is broken down into carbon dioxide and water again as energy is released (fig . B 6.20) . Wood is made up of about 50% carbon (C) from the carbon d ioxide in the air. This carbon remains stored in the forests and timber prod­ ucts for the whole time between photosynthesis and the oxidation of the wood (degradation by fungi and bacteria, or combustion) . Wood therefore makes a major contribution to reduc­ ing carbon d ioxide concentrations. The forests of Europe hold about 20 times the amount of carbon dioxide that is released i nto the atmos­ phere every year through emissions. The use of wood and wood-based products in building prolongs this storage effect. And using more timber and so curtailing the production of steel and concrete reduces the emissions of carbon d ioxide even further.

Solar energy 1

0

-

-

/ 1 "

carbon dioxide + water 6CQ, + 6H,O

--.

oxygen + biomass 60, + C,HI2O,

a 56.5 MJ calorific energy

" r'\ V

1 .44 kg CO, 0.56 kg

1 kg wood kg 0,

1 8.5 MJ heating value

b

B 6.20

B 6.19

Physical parameters of board-type wood-based products B 6.20 Simplified illustration a Photosynthesis of wood b Combustion of wood B 6.21 -22 Structure made from cross-laminated timber, "Parasite" house, Rotterdam, Netherlands, 2001 , Korteknie & Stuhlmacher

Wood and sustainability

Forests cover approx. 30% of the Earth's land surface. Whereas forests in the developing countries have been d isappearing in recent years (-9%), stocks of trees in the industrial­ ised nations have increased (+ 3% ) . Based on this growth, it seems sensible to increase the use of timber products in Europe. Roughly half of the timber stocks available g l o­ bally (approx. 3.3 billion m3 annually) are used

B 6.22 75

Metal

B

The d iscovery and use of metals had a great influence on the cultural development of human­ kind in ancient times. Accordingly, these epochs have been named after the corresponding metals. Up until the New Stone Age, i .e . up until about 6000 BC, metals that occur in pure (native) form in nature were used to a limited extent, e . g . for jewel lery. The next milestone is around 4300 BC, which heralded the dawn of the Cop­ per or earliest Bronze Age in Central Europe. During this period techniques for extracting metals from ores, metal casting and the pro­ duction of tools spread . The discovery of the more hardwearing bronze - an alloy of copper and tin - in Egypt around 3500 BC characterised the next cultural epoc h . Bronze became popular for household utensils, weapons, tools, jewellery and much more besides. The ongoin g development of metal casting even made possi ble the first series pro­ duction runs. The outcome of these technical developments was new professions, and trade relations started to expand. New social struc­ tures formed in society, which led in turn to the first city-states. After about 1 200 BC iron began to replace bronze because it was more readily available. However, at first iron was d ifficult to work. The earl iest furnace for producing iron , the so­ called bloomery, was heated with charcoal and produced a lump of iron and slag from the orig­ inal iron ore. Considerable hammering was required to separate the slag from the iron and then turn the lump of iron into the desired shape.

Waterloo I nternational Rail Terminal, London, UK, 1 993, N icholas Grimshaw & Partners B 7.2 Overview of metals and their alloys B 7.3 Golden roof, Secession building, Vienna, Austria, 1 897, Joseph Maria Olbrich B 7.4 Iron frame, Gare du Nord, Paris, France, 1 863 B 7.5 Large-scale use of cast steel in industrialisation: cast iron wheels, steelworks in V6lklingen, Germany, 1 9th century. B 7.1

76

It was not until the 1 4th century that the tech­ n ique of using bellows in raised blast-furnaces to generate temperatures of about 1 500°C became widespread in order to reduce larger q uantities of molten iron. In his 1 2 books with the title De re metallica /ibri XII published in 1 556, Georg ius Agricola describes the state of the art of that time, techniques that did not undergo any noteworthy changes until the dawn of industrialisation in the 1 9th century. The consumption of great q uantities of wood had already led to the d isappearance of large areas of forest by the 1 4th century. The pro-

7.1

duction of 1 kg of iron required about 1 25 kg of wood to supply the necessary energy. But in 1 709 Abraham Darby succeeded in firing a blast-furnace with coke, and by the end of the 1 8th century coke was increasingly replacing wood as a fuel. This resulted in metal produc­ tion being transferred to coal-mining regions. It was in Coalbrookdale (UK) in one of these regions that the first cast iron bridge was built in 1 779. The growing demand for rolled iron products in the building industry encouraged further technical progess. Metal in architecture

Cramps of iron and bronze for holding together the individual stones of Greek and Roman structures were the first metal components used in the building industry. But it was not until the 1 9th century that metal i n the form of cast iron began to be used for load bearing ele­ ments. The methods of building initially fol­ lowed the practices that had been used for centuries for timber and stone. But delicate constructions quickly showed the unlimited shaping opportunities and the higher load­ carrying capacity of this material . One famous example is the reading room of the St Gene­ vieve l ibrary in Paris ( 1 850) by Henri Labrouste. The use of i ron left exposed was at first accept­ ed only for bridges, industrial structures and railway stations (fi g . B 7.4) . Owing to its effi­ ciency and fast erection, cast i ron was favoured for the world expositions in London ( 1 85 1 ) and Paris ( 1 889). Joseph Paxton used prefabricated cast iron components for his "Crystal Palace" in London in 1 85 1 , the size of which - 564 x 1 24 x 33 m - would even today cause some astonishment. In Paris on the other hand, renowned architects and artists protest­ ed against Gustave Eiffel's 300 m tower for the world exposition of 1 889. At the start of the 20th century, the easy mouldability of metals was used to great effect by the proponents of Art Nouveau (fig . B 7 . 3 ) . Development o f steel construction By the end of the 1 9th century it was possible to obtain large quantities of molten steel direct­ ly from pig iron using the Bessemer method invented in 1 856, which had enabled cheaper

Metal

Metals

Alloys

Alloying constituents

carbon content

carbon content

:;, 2 %

< 2 %

small amounts of: copper chromium

small amounts of: nickel chromium vanadium tungsten

small amounts of: titanium copper etc

copper 80-90% tin 1 0-20%

copper 65% zinc 35%

B 7.2

production of steel on a large scale. It thus became possible to construct large industrial plants (fi g . B 7.5). One of the first steel bridges in Europe was that over the Firth of Forth in Scotland ( 1 889). The efficiency of steel and the economic devel­ opments in America led to a new type of build­ ing - the skyscraper, which underwent a rapid evolution: the first high-rise blocks in Chicago and New York were built around 1 890 and had 1 0-1 5 storeys (fig . B 7 .9) , but the Empire State Building built just 40 years later had 1 03 stories and even today is still in the top 1 0 of the world's tallest buildings. For the first time in history of architecture, the external envelope could be completely transparent (fig . B 7 . 1 ) - thanks to structural steelwork.

This particular metallic bond allows us to explain all the physical properties such as high density and strength, the high melting point plus the good thermal and electrical conductiv­ ity. Metals can be moulded and usually have shiny surfaces. Some metals exhibit magnetic properties. Their high thermal conductivity means that they feel cold to the touch, but inci­ dent solar radiation is absorbed and results in a significant rise in temperature. One particular feature of the metals is their plastic deformation (the so-called yielding) under high loading. For their use in building therefore it is not the u ltimate load that governs but rather a stress equivalent to the yield point, which is reached at an elongation of 0.2%. B 7.3

Deposits and production

Contemporary applications The majority of metal used in the modern con­ struction industry is in the form of rolled steel sections for loadbearing members in single­ storey sheds and high-rise buildings, and steel bars for reinforced concrete structures. How­ ever, metal is also used in many components from outside facilities to roof elements (e.g. cladding and roof coverings) , and for fixings, fasteners and services. Remarkable examples of the use of metal facades can be seen at the offices of the John Deere Company dating from the 1 960s (Eero Saarinen) , which uses weathering steel, the Lloyds headquarters in London (Richard Rogers) , which is clad with stainless steel panels (fig. B 7 . 1 1 ) , and the copper facade to the railway signal box in Basel by Herzog & de Meuron (fig. B 7. 1 6) . Further possibilities for steel construction can be seen in the designs of Frei Olto (see "Synthetic materials", p . 90, fig. B 9. 1 ) , which reveal the path of the forces. Norman Foster showed us the boundaries of technical feasibility in steel high-rise building i n his design for the 1 000 m Mi llennium Tower in Tokyo.

Although the majority of chemical elements are in fact metals, they account for less than 1 5% of the material in the Earth's crust. Only the so­ called precious metals such as gol d , si lver and p latinum occur in nature in their pure (native) form. The metals important for the building industry (e. g . iron, aluminium, copper) are obtained from ores (sulphides and carbonates) but first have to be converted to oxides in vari­ ous preparatory processes before they can be smelted (reduced) in blast-furnaces. Classification of metals

We distinguish between heavy metals (> 4500 kg! m3) and light metals « 4500 kg/m3) . The classi­ fication into ferrous and non-ferrous metals (fi g . B 7.2) shows the great importance of iron and its alloys in comparison with the other met­ als. Metals can be pure - consisting of the atoms of one chemical element - but can also be combinations of two or more elements (so­ called all oys) , i.e. a blend of a metal and anoth­ er substance (metallic or non-metallic such as silicon or phosphor) . Even small proportions of other substances can change the material properties of metal al loys. This allows the mate­ rial to be adapted for diverse applications.

Metal

Material lifecycle

Metals (Greek: metal/on mine) are those chemical elements whose atoms combine to form crystalline structures with free electrons. =

Metals can be returned to the production proc­ ess without impairing the q uality of subsequent products. In fact, recycling represents an B 7.5

77

Metal

Shaping and jointing of metals

B B

B B

7.6 7.7

7.8 7.9

Shaping and jointing of metals Semi-finished products made from metal sheets: a Trapezoidal profile sheet metal b Perforated sheet metal c Stamped sheet metal d Expanded metal Ropes and rods: e Cable net f Knitted fabric g Woven meshes of strips h Woven meshes of ropes and rods Sections: i Rolled stainless steel sections j Extruded aluminium sections (window frames) Castings: k Cast steel node I Washbasin tap Semi-finished products made from various metals Structural steelwork, Times Tower, New York, USA, 1 905, Daniel Burham

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advantage because it requires much less ener­ gy to melt down the metal. The reuse q uota for scrap metals sent for recycl i n g is 90%, in the case of steel almost 1 00%. Behaviour in fire, fire protection

Metals are incombustible, but lose their strength at high temperatures. The modulus of elasticity and the yield point fal l , and the metal deforms. The maximum temperature for steel is approx. 500-600°C, depending on the cross­ section. In order to protect building occupants against the failure of components in a fire, structural steelwork must be protected, either by enclosing it in a fire-resistant material or coating, by filling hol low members, or by install­ ing fire extinguishing systems. Corrosion

Corrosion is the chemical or electrochemical reaction of a substance. Metals oxid ise in high humidities and through contact with wet or damp materials. Galvanic corrosion takes place at the point where two disparate metals are in contact in the presence of an electrolyte, e . g . water. I n this case the less noble metal is corroded, a

fact that must be taken into account by consid­ ering the electrochemical series when using non-ferrous metals. The series extends from the non-noble metals magnesium and aluminium to the noble metals silver and gold. Simplified , the series looks l i ke this: Mg-AI-Zn-Cr-Fe-Ni-Sn-Pb­ Cu-Ag-Au. In order to prevent corrosion, p i pes of copper, for example, should be laid down­ stream of those made from iron or zinc, and not vice versa. As the working or machining of metals can change their properties, especially in the case of steel , an electrochemical reaction can take place even within a steel component, e . g . at bending points, welds or through alloying con­ stituents.

7.6

Passive corrosion protection is provided by numerous forms of metallic and non-metallic coverings such as paint, powder and plastic coatings, enamel, galvanising and zinc plating. Such coatings and coverings should not be damaged during erection (e.g. through bolted connections) . Corrosion protection prolongs the l ifetime of external components or internal components where the humidity is high. Natural protective layers Copper, aluminium, lead and zinc plus a number of steel alloys (stainless steel , weather­ ing steel) form protective layers on their surfac­ es that prevent further corrosion. Shaping and processing of metal

Corrosion protection We distinguish between two fundamental approa­ ches to the protection of components against corrosion: active and passive protection. Active protective measures are forms of con­ struction that present I ittle or no chance for cor­ rosion to gain a foothold. The targeted "sacrific­ ing" of a less noble metal with an electrically conductive attachment to the component can actively prevent corrosion.

We d istinguish between cold- and hot-working and mechanical machining processes. In cold­ working the geometry of the atomic metal microstructure is altered mechanically. In hot­ working it is not the absolute temperatures (for steel 900-1 300°C, for lead 20°C) that govern, but rather the possible rearrangement of the crystal lattice, a process that also occurs dur­ ing the hardening and tempering of steel. Therefore, rol l i n g , pressing and forging can be

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used for both hot- and cold-workin g depending on the material (fi g . B 7 . 6 ) . Forging Forging can be carried out manually or by machine using a hammer and anvil or with pressing moulds (forg i n g d ies) . Forg ing can be both a cold- and a hot-working process. Diverse shapes are possible. Casting Casting permits any shape to be formed . How­ ever, further processing of steel castings is only possible using machining methods. Tin and bronze are suitable for the production of delicate, precision castings. Rolling Workpieces (e.g. rolled steel sections) are shaped in several operations in a rolling mill by applying high contact pressures through a system of variously sized rolls. Extrusion In extrusion the metal is forced through an opening (die) to form the desired final shape. This process i s particularly suitable for non­ ferrous metals, which enables, for example, complicated aluminium cross-sections for win­ dow frames to be produced. Extrusion can be both a cold- and a hot-working process. Drawing Wires, rods and reinforcing bars are produced by drawing, usually a COld-working process. Twisting Sections, rods and wires for cables are twisted about themselves. The enlarged surface area of twisted reinforcing bars, for instance, improves the bond between steel and concrete.

Mechanical machining A wide range of metal products i n the building industry require mechanical machi n i n g . Milling, dri l l i n g , fi l i n g , sawing and turni n g are the so­ called material-removal machining options. It i s possi ble t o c u t a thread in sol id material, mill holes, or turn hinges for doors and windows, to name just a few examples. Bending and stamping are among the COld-working process­ es (e.g. for sheet metals) . And the folding of thin sheet metal creates rainproof joints for roof surfaces (see "The building envelope", p. 1 24 ) . Jointing techniques

N umerous methods are used to join metals together. We d istinguish between detachable joints such as screws, bolts, nails, rivets and pins, and the non-detachable ones such as welding, solderi n g , brazing and bonding with adhesives. Welding involves melting the workpieces at their point of contact to create a material bond at the joint. In soldering, a molten metal or an al loy with a low melting point joins together two other metal workpieces. Products, semi-finished products

The great number of metal products relevant to building means that it is only possible to men­ tion a few groups here: castings, drawn wires, rods, reinforcing bars and meshes, p i pes, steel sections, welded sections, cold-formed sec­ tions, extruded sections, rings, collars, d iscs, bolts, screws, turned parts and many forms of sheet metal (figs B 7 . 7 and B 7 . 8 ) .

Ferrous metals

I ron and its alloys, especially steel, are suitable for diverse technical applications and are therefore required in such large q uantities that today the production plants shape many Euro­ pean cities.

Iron

I ron is the most widely used metal worldwide. I ron deposits account for about 5% of the chemical e lements available in nature and it thus ranks fourth after oxygen, silicon and alu­ minium. Pig iron contains approx. 4% carbon and is brittle. Chemically pure iron is hardly ever used because of its low strength and rapid oxidation (corrosion) . But as the proper­ ties of iron can be i mproved by reducing the carbon content, it is mainly further processed to form steel and other iron al loys. Production and recycling I ron ore is mixed with lime i n a blast-furnace and reduced to iron at temperatures of 1 500°C. The process also produces slag and gases from the non-metallic constituents in the iron ore. Some of the carbon in the iron dissolves, which lowers the melti ng point. The result is pig iron containing carbon, which is heavier than the slag and so s inks to the bottom of the fur­ nace from where it can be drawn off continu­ ously. The addition of scrap metal to this proc­ ess results in two advantages: firstly, it improves the qual ity of the pig iron, and sec­ ondly, the primary energy requirement of recy­ cling is only about 20-40% of that req uired for new production. Materials for casting Compounds of iron with a carbon content > 2% are known as cast iron, those with < 2% cast steel (fig . B 7 . 1 0) . The properties and designa­ tions of cast iron depend on the form of the car­ bon in the solidified casting material. We d istin­ guish between cast iron with lamellar graphite (grey cast iron, GJL), with spheroidal graphite (ducti le cast iron, GJS) and malleable cast iron (GJ M ) . The latter turns a l i g hter colour in an oxi­ dising atmosphere (white cast iron). In sand moulding the carbon remains in the material and gives it a dark colour (grey cast iron, L) . There are also al loys of cast iron . Cast i ron

79

Metal

Density

Abbreviation

Ferrous metals

[kg/ m']

Thermal conductivity

Tensile Coefficient Electrical of thermal conductivity strength expansion

Modulus of

Elongation Yield

elasticity

at failure

& 0.2% proof stress

[W/ mK]

[mm/mK]

[m / flmm']

[N / m m']

[%]

[N / mm']

0.8-0.3

98/285 2

[N / mm']

Cast iron cast iron (lamellar graphite)

GJL

7 1 00-7300

40-50

0.Q1 2

5-7

1 00-450 (600-1 080)'

78000-143 000

cast iron (spheroidal graphite)

GJS

7 1 00-7200

36.2-31 . 1

0.Q1 3

5-7

400-900 (700-1 1 50) 1

1 69 000- 1 76 000

7850

40-50

0.Q1 2

5-7

380-1 1 00

7850

56.9

0.Q1 2

5

7850

48

0.01 2

1 8-2

240-600

2 1 0 000

7-25

200-830

340-470

2 1 2 000

25

235

5

450-680

2 1 2 000

1 7-20

275-355

Steel cast steel structural steel Fe 360 BFN (RSt 37-2)

WT St 37-3

Fe 5 1 0 C (St 52-3

WT St 52-3

U)

S235JR

1 .0038

S235J2W

1 .8965

S355JO

1 .0553

S355J2W

1 .8965

stainless steel V2A (X 5 CrNi 1 8- 1 0)

1 .4301

7920

1 4. 5

0.01 6

1 .5

500-700

200000

45

1 90

V4A (X 6 CrNiMoTi 1 7- 1 2-2)

1 .4571

7960

15

0.01 7

1 .4

500-730

200000

45-50

2 1 0-255

1

In contrast to steel, the compressive strength and tensile strength of cast iron are not identical. The compressive strengths are therefore given in brackets.

2 Owing to the low elongation at failure, these values apply to a 0 . 1 % proof

materials are brittle, cannot be shaped by forg­ ing, and only certain types can be machined . The melting point of cast iron is lower than that of steel . Cast iron with spheroidal graphite can be welded to a limited extent and i s more resis­ tant to corrosion. A cast steel that undergoes no further shaping is known simply as cast steel (GS) . Cast steel al loys can be readily welded to structural steel and are used for jOints with complicated geometry (fig . B 7 . 7 ) . Applications Cast i ron in building is suitable for drain p i pes, radiators and bath tubs, for instance. Inspec­ tion covers and hydrants made from malleable cast iron are also common. Fittings, hardware and keys (i.e. ironmongery) are mad e from white cast iron. Components made from d uctile cast iron are used for connecting tie bars, guy rods, bracing , etc. If no test certificates are available, the proper­ ties of load bearing cast parts must be proven in elaborate tests. This is the reason for the building industry's sluggish acceptance of the more efficient casting materials made from the special alloys that have been developed i n recent years.

B 7.10

Steel

Steel is an alloy of iron with a carbon content < 2 % . Stee l with a low carbon content has a higher melting point, but can be forged more easily and is less brittle. The modulus of elas­ ticity and weldabil ity are the decisive factors contributing to the wide use of steel in build i n g . Structural steel contains approx. 0.2% carbon. Proportions of other chemical elements - even very tiny amounts - can influence the properties of the steel quite considerably, e . g . corrosion behaviour. New steel variations are constantly being added to the 2000+ types currently covered by standards. Production and recycling There are three methods for reducing the car­ bon in pig iron and thus producing steel. In the air refining process the carbon is removed from the pig iron, either by injecting air (Thomas process) or pure oxygen (Linz-Donauwitzer LD method ) . T h e open-hearth refi ning processes include the Siemens-Martin and the electric-arc furnace processes. The Siemens-Martin process was developed by Wilhelm and Friedrich Siemens

in 1 856 for convertin g scrap metal back into steel. Using a system for preheating gas and air, the temperature of approx. 1 800°C neces­ sary for producing molten steel is generated in a d ish-like furnace. I n 1 864 Pierre und Emile Martin managed to apply this method success­ fully, and it was set to remain the most impor­ tant method for producing steel for the next 1 00 years. The electric-arc furnace method requires an electric arc to be fired between two electrodes. The extremely high temperatures generated by the arc are sufficient to melt even hig h-quality metal alloys. The LD and e lectric-arc furnace methods are the most common steel making methods in use today. Heat treatment The physical properties of steel can be changed through specific heating and cooling or hammering (forging) because - depending on the carbon content - various crystal struc­ tures ensue at temperatures of 700-1 500°C. We d istinguish between annealing, hardening and tempering. Steel alloys

Steel alloys with other constituents must be clearly d istinguished from steel because they can exhi bit considerable d ifferences in terms of their properties. The development of efficient steel alloys is an ongoing process, and high­ strength alloys of this kind are used , for exam­ ple, in automotive and mechanical engineering applications. Stainless steel Corrosion-resistant steels are usually grouped together under the heading of stainless steel . Such al loys contain a t least 1 0% chromium, but also other metals such as nickel, molybdenum, titanium, vanadium and tungsten; the carbon content l ies below 1 .2%. In contrast to steel , stainless steels form a protective, so-called passive, coating under normal conditions, which renews itself if damaged. Nevertheless, seawater or high humidity in combination with salts (e.g. in thermal baths) can still attack some types of stainless steel. B 7.1 1

80

B 7.12

Metal

B 7 . 1 0 Physical parameters of ferrous metals common in building B 7.1 1 Stainless steel facade, Lloyds headquarters, London, UK, 1 986, Richard Rogers Partnership B 7. 1 2 Weathering steel , Kalkriese Museum, Bramsche, Germany, 2002, Gigon + Guyer

B 7 . 1 3 Various anodised aluminium surfaces, Town Hall, Scharnhausen, Germany, 2002, Jurgen Meyer H . B 7.13

The energy required to manufacture stainless steel is higher than that for steel owing to the additional alloying elements requ ired . As stain­ less steels often require no further surface fin­ ishes, they can be readily recycled because the electric-arc furnace process can melt down these high-quality steels. Various mechanical surface treatments can be used on stainless steel, e . g . brushing, grinding, acid-etching or sand-blastin g . Building authority approval is required when stainless steel is to be used for load bearing applications. Stainless steel is used for facades, roof coverings, pipes (flues), safety barriers, handrails, kitchen furniture, hardware, fasteners and much more. Weathering steel Alloys of steel with additions of copper, chromi­ um, nickel and phosphorus gradually form a permanent layer of rust upon exposure to the atmosphere (fig . B 7 . 1 2) . Owing to this process of rust formation, minimum thicknesses should be taken into account in the case of load bear­ ing components. Nevertheless, in marine envi­ ronments or other unfavourable climatic condi­ tions the rust layer does not provide permanent protection.

Non-ferrous metals

Compared with aluminium, lead, zinc, copper and their alloys, silver, gold, magnesium and titanium are less important in the building industry and therefore are not considered any further here. Aluminium

Although aluminium is the third most common element and the commonest metal in the Earth's crust, it was not discovered until the 1 9th century. Its extraction was so complicated that it was initially treated as a very precious metal. Production and recycling The raw material of aluminium is bauxite, which is obtained from open-cast mines . In a process not unlike that used for iron, aluminium oxide is

obtained first. Caustic soda (sodium hydroxide layer a n d i s therefore very durable. On building solution) is used to separate the aluminium sites aluminium must be protected by sheeting or similar means against the effects of concrete hydroxide from the other constituents of the ore and lime or cement mortars because their alkali and this is subsequently heated to 1 200°C to constituents can attack the surface of alumini­ obtain aluminium oxide. The high meltin g tem­ um. perature of approx. 2000°C is lowered by add­ The oxide layer on aluminium can be reinforced ing cryolite (Na AI F6) . Aluminium can then be 3 extracted from the mixture at approx. 1 000°C by considerably through anodisin g . Depending on the period of immersion in an electrolytic bath, applying an electric current of between 30000 colours between light grey, grey-brown, bronze and 1 00 000 A. The process requires a high and dark brown are possible (fig. B 7 . 1 3) . energy input and the by-products of the elec­ Joints and junctions o n aluminium construc­ trolysi s represent a problem for the environ­ tions and facade cladding must take into ment. This i s why aluminium is already being recycled to a large extent, which saves 75-90% account the fact that the coefficient of thermal of the primary energy, the exact saving depend­ expansion of aluminium is about twice that of steel . ing on the method of generating the electricity. Nevertheless, in the price of aluminium the cost Applications of energy accounts for about 40%. Extruded sections for supportin g frameworks, Properties and processing windows and post-and-rail facades represent the most i mportant applications for aluminium Aluminium is used wherever its low weight in building . With correspondi ngly large num­ only about a third of that of iron and steel - is beneficial. bers, the forms of the extruded sections can be Aluminium materials can be mil led, sawn and varied almost at will with l ittle effort. Further applications include plain and profiled sheets drilled . They are light in weight, read ily mould­ for facades and roofs, perforated sheets ed, easy to work and can be polished. Shaping is performed by rolling, stretch-form­ (acoustic ceilings), lamp bodies, hardware made from cast aluminium and much more i n g , pressing, drawi n g , forging and upsettin g . Aluminium is more ductile than steel a n d so besides. Moreover, aluminium foil is popular for waterproofing. extruded sections can be manufactured with considerably less energy input. Aluminium foams Aluminium can be welded only in an oxygen­ free atmosphere because the formation of the Metal foams made from aluminium exhibit a lower thermal conductivity and relatively good layer of oxide must be prevented during the wel d i n g procedure as wel l . sound insulation properties. They have a good compressive strength coupled with a low The aluminium alloys used i n building are gen­ erally also referred to simply as aluminium. weight and are easy to work. They are already in use in the automotive sector. In principle, it is These alloys contain about 2-2.5% of elements possi ble to produce such foams from other such as s i l i con, magnesium, copper, manga­ metals as well . nese, etc. The European material numbering system includes a material designation for every type of Lead After aluminium, lead is one of the commonest metal. For example, aluminium alloy EN AW 3 1 01 has the chemical designation AIMn 1 . The metals in the Earth's crust. It is a non-ferrous main constituent of this material, besides alu­ metal which is classed as a heavy metal because of its high density. minium, is manganese (0.9-1 .5%) plus about 2% of other alloying constituents (Fe, Si, M g , Zn, Properties Lead has a low tensile strength and exhibits Cr, Zr and Ti) . Aluminium corrodes immediately upon exposure large temperature-induced changes in length. to the air, but forms a permanent protective It can absorb sound waves, x-rays and radio-

81

Metal

active radiation. Lead is attacked by strong acids, fresh mortar and concrete, but is extremely resistant to corrosion. Upon expo­ sure to the air it forms a permanent l ayer of oxide that subsequently carbonates with car­ bon dioxide. This layer is l ight grey in colour and insoluble in water. As lead is very soft, it is easy to rol l , and easy to shape by hammering and moulding . It can also be soldered and welded. Lead has a matt grey colour. Production and recycling A lead sulphide concentrate is obtained after several passes throug h so-called flotation cells. This involves frothing up the finely ground ore and copious aeration in order to separate the metal compounds from other constituents. The subsequent smelting of the dried concentrate permits the addition of a high proportion of sec­ ondary raw materials such as lead scrap. The process requires a great deal of energy and a toxic dust is produced, which must be d is­ posed of in landfil l sites. The recycling quota is in excess of 50%, which can help to save about 40% of the energy required for production. Applications Sheet lead is suitable for roof coverings and facades (fi g . B 7 . 1 4) . Owing to its corrosion resistance lead is also used as a protective sheathing (e.g . for electric cables) . Lead is suitable for shielding radiation in nucle­ ar medicine applications and as a raw material for rustproofing paints (red lead ) . Owing to its toxic effects lead should be avoided these days because it can become enriched in the food chain. Zinc and titanium-zinc

The Romans were already using zinc in the form of brass, without being aware of the zinc content itself. Marco Polo described the pro-

B 7.14 82

duction of zinc oxide for medicinal purposes at the end of the 1 3th century. I n d ustrial production of zinc began around 1 850. Zinc alloys ( e . g . titanium-zinc made from 99.995% zinc plus 0.003% titanium) have high­ er strengths than the relatively brittle zinc itself. The alloys can be soldered and welded and have a lower thermal expansion than zinc. It is for this reason that the building industry makes use of titanium-zinc almost exclusively. Zinc i s weather-resistant because, like lead, it forms a permanent layer of carbonate when exposed to the air. It is therefore frequently used as a protective coatin g (galvanising) on other metals such as steel, copper, etc. Production and recycling Zinc ores (sphalerite, smithsonite and zinc oxide) are prepared using froth flotation - simi­ lar to lead. To extract the zinc, both the so­ called dry process, in which coal reduces the zinc oxide in the by-product coke oven, and also the wet process, in which the reduction is performed electrolytically, are employed. The preparation of the zinc ore directly at the mine is an attempt to save energy. About 30% of the worl dwide production of zinc is obtained from secondary material (scrap). Applications Titanium-zinc in sheet form is suitable for facades (fig . B 7 . 1 5) , roof g utters and pipes. Zinc can be cast very precisely and in very intricate moulds. There are many z inc-based alloys relevant to the building industry, e . g . d ie­ cast zinc for hardware, brass, nickel silver and solders for solderin g . O n e i mportant area o f application for zinc is its use as corrosion protection on steel compo­ nents because zinc is much more resistant owing to the permanent protective layer that

B 7.15

forms. There are many methods for applying this protection to steel components for use externally: hot-di p galvanisi n g , electrogalvanis­ i n g , zinc spraying, etc. The durabil ity of zinc coatings essentially depends on the carbon dioxide content of the surrounding air. Copper

The word copper stems from the Latin word cuprum and is evidence that the Romans mined the ore on the island of Cyprus (Latin : cyprium) . Copper is one of the heavy metals. Properties Copper has a shiny red colour and is very hardweari n g . It is easy to work, is easy easily shaped, soldered and welded, but is difficult to cast. Copper conducts heat and electric cur­ rent very wel l . Pure, soft copper is d ifficult to work, but its strength improves considerably in the form of copper al loys. Patina Copper is resistant to effects of gypsum, lime and cement, and forms a dense, greenish layer of copper salts upon contact with the air. Under normal urban conditions this patina builds up over a period of about eight years. Its colour d uring this process ranges from red-brown to dark brown and grey to the typical green. This process can be reproduced chemically prior to erection (so-cal led pre-patination) . Verd igris on the other hand is a copper salt that forms in the presence of acetic acid and is often m istaken for the copper patina. In con­ trast to the patina, verdigris is toxic and soluble in water. Production and recycling Like lead and zinc, the copper ores chalcopy­ rite and chalcocite are prepared using the froth flotation process. The reduction takes place in

B 7.16

Metal

Non-ferrous metals

Aluminium

EN AW-7022

(AIZn5Mg3Cu)

Lead

[kg/m"]

Electrical Thermal Coefficient of conductivity thermal expansion conductivity [ml!1mm"] [mm/mK] (W/mK]

Density

Tensile strength [N/mm"]

Modulus of elasticity [N/mm"]

Elongation at failure [%]

Yield & 0.2% proof stress [N/mm"]

2703 ' /2699 '

222

0.023

8-25 ' /2-8 '

1 30

n.a.

37 20

72 200

2780

4 1 0-490

70 000

3-8

330-420

1 1 340

35

0.029

4.8

1 0-20

20000

50-70

5-8

90-1 20 ' / 1 50-230 '

40-70 '/ 80-1 1 0 '

Zinc

7 1 30

113

0.033/0.023'

1 6.9

1 50/220 '

94000

25/ 1 5 '

1 60/220

Titanium-zinc Z1 (ZnCuTiAI)

7200

1 09

0.022

17

1 50-220

80000

;,, 35

1 00-1 60

Copper

8940

394

0.D1 7

1 20 000

25-1 5 ' / 50-30 3

8900

329

0.01 7

57 n.a.

1 60-200 ' / 200-250 3

CW024A; 2.0090

200-51 5

1 32 000

Copper-tin alloy (bronze)

8600-8800

54-75

0.01 7-0.0 1 9

ca. 9

240-300

Copper-zinc alloy (brass)

8300-8500

1 1 7- 1 59

0.01 7-0.020

ca. 1 6

370-740

CuZn37; CW508L; 2.321

8400

121

0.020

ca. 1 6

740

' cast

' rolled

3 annealed

40-60 1 / 1 00-1 50 3

3 - 40

35-320

80000-1 06000

5-12

1 30-1 80

75 000-1 20000

1 0-20

1 50 - 490

10

440

1 1 0 000

' Values for parallel with and transverse to rolling d i rection B 7.17

a converter. However, for applications in elec­ trical engineering, which account for about 60% of copper production, the copper is extracted electrolytically (electrolytic copper) . More than 50% of the production is based on recycled material, which saves 86% of the pri­ mary energy requirement. Processing and applications All the conventional metalworking techniques are suitable for copper and its alloys. But the material's high thermal conductivity makes it difficult to weld, although it is easy to solder and bond with adhesives. Sheet copper is used for facades and roofs (fig. B 7 . 1 6) but is also suitable for waterproof­ ing tasks because it can be bonded with bitu­ men. Copper is suitable for manufacturing pipes, e.g. for heating systems, and is widely used in electrical engi neerin g (see "Building services", p. 1 50). Alloys of copper and tin: bronze

The name bronze stems from the Latin brundi­ sium (from Brind isi) should these days really be replaced by the standardised designation "alloy

of copper and tin" because there are also alloys of copper and aluminium (previously known as aluminium bronze) . Bronze is produced in a smelting furnace at 1 000°C and contains a pro­ portion of tin amounting to between 1 0 and 20%. Bronze is extremely durable and weather­ resistant. It is harder than brass and copper, and exhibits good resistance to corrosion and abrasion, which is why it is used for long-lasting bearing bushes. Bronze has a dark surface which can be pol­ ished to a shiny gold colour with little effort. Evi­ dence of this can be seen on the many bronze sculptures and objects in public areas - parts that frequently touched by admirers and pas­ sers-by have shiny, pol ished surfaces. Bronze is suitable for pipe couplings, hardware and gas, water and steam fittings. In addition, bronze i s used for casting bells and artistic objects. Owing to its durabi l ity, bronze window frames and doors can be found on many his­ torical buildings, even on prestigious contem­ porary buildings (fi g . B 7 . 1 8) .

Alloys o f copper and zinc: brass etc.

These alloys contain at least 50% copper. These days we disti ng u i sh wrought copper alloy (previously known as brass) from gunmet­ al and nickel silver. The wrought copper alloy consists of 55-85% copper plus zinc. Gunmet­ al is an alloy of copper, zinc and tin (each 1 -1 0% ) . N ickel silver consists of 50-60% cop­ per, 1 0 -25% nickel and zinc. Copper alloys are read ily shaped, easy to work and - in contrast to pure copper - can be cast too. Brass is h i ghly resistant to corrosion and has a shiny gold appearance after working or polish­ ing. However, over time the surface tarnishes to a dark matt finish. Copper al loys are used in many applications, e . g . brass for electric terminals, screws and nuts, pipe fittings and hardware. One architectural example of the use of a woven metal mesh made from brass is the syn­ agogue in Dresden (fi g . B 7 . 1 9) . Nickel silver i s suitable for contact surfaces i n electrical engineering, but also for hardware and pipe fittings.

B 7.14 Cladding of sheet lead, Parco dell a Musica Auditorium, Rome, Italy, 2002, Renzo Piano B 7.15 Cladding of sheet titanium-zinc, Guggenheim Museum, Bilbao, Spain, 1 997, Frank Gehry B 7.16 Cladding of copper strips, signal box, Basel, Switzerland, 1 999, Jacques Herzog & Pierre de Meuron B 7.1 7 Physical parameters of non-ferrous metals and alloys used in the construction industry B 7.18 Bronze facade sections, Seagram Building, New York, 1 958, Ludwig Mies van der Rohe B 7.19 Brass mesh fabric, Dresden Synagogue, Germany, 2001 , Wandel Hoefer Lorch + Hirsch

83

Glass

B 8. 1

The invention of the sand core technique ena­ bled g lass to be made in small q uantities after about 6000 BC. The blowing iron developed by Syrian craftsmen around 200 BC meant that it was possible to produce transparent vessels. Roman builders were already using a form of cast glass for windows. However, owing to the method of production, the glass was not trans­ parent, merely translucent. G lass production between the 4th and 1 9th centuries was dominated by two methods. I n the crown g lass method the glass blower creat­ ed a circular pane up to 2 m in d iameter by rotating the glass around the blowing iron. This method of production left the typical raised centre section - the bullion. Larger areas of glazing were created by joining together such panes and smaller g lass fragments by means of lead cames. Contrasting with this, the blown cylinder sheet g lass process enabled the production of larger, almost flat panes. To do this, the blowing iron was used to form a cylinder that was then slit while still hot and subsequently rolled out on a flat bed. However, the surface finish possible with this method was far less uniform than that of a pane of crown g lass. The next major development took place in France in 1 687: Bernard Perrot developed the method of casting g lass on a preheated cop­ per plate and subsequently i mproving the sur­ face finish by grinding and polish i n g . Mirrors were produced by polishing one side only. Products made with this method were known as pol ished plate glass. The demand for timber for glass production was enormous during this period because it was needed to provide heat and to provide potash. G lass therefore remained a luxury reserved for prestigious buildings until well into the 1 8th century. The windows of Gothic churches are excellent examples of the skills of the glass blowers of this period. B 8.1

Glass pavilion at the Summer Academy in Rheinbach, Germany, 2000, Marquardt Architekten

Industrialisation

B 8.2

Systematic classification of glass products

B 8.3

Physical parameters of silicon-based glass

B 8.4

Glass curtain wall, Bauhaus, Dessau, Germany,

B 8.5

Profiled glass facade, extension to the art gallery

During the 1 9th century glass manufacturers began to fire their melting furnaces with coal. New methods optimised the process of melting and reduced the consumption of solid fuel . Lucas a n d Robert Chance improved the blown

1 926, Waiter Gropius in Winterthur, Switzerland, 1 995, Gigon + Guyer

84

cylinder sheet g lass process in 1 832 by unroll­ ing and stretching the slit cylinder in a furnace. Thanks to this new technique it became possi­ ble to produce the large numbers of better­ qual ity panes, e . g . for the Crystal Palace in London ( 1 85 1 ) . The production of glass became more efficient and cost-effective thanks to these various technological developments. In 1 905 - more or less at the same time - Emile Fourcault and Emile Gobbe from Belgium as well as the American I rving Col burn developed different methods of drawin g flat glass directly out of the melt. By 1 9 1 9 Max Bicheroux from France had man­ aged to combine the various operations for producing cast g lass by shaping the hot glass with cooled rollers, cutting it while stil l hot and then conveying it on flat beds through an annealing lehr. It was not until 1 959 that manufacturers were in a position to produce really flat g lass. I n that year Alastair Pilkington invented the float glass technique in which the glass is poured onto a bath of liquid tin and allowed to solidify. Owing to the efficiency of this method, it quickly became established for producing almost all types of flat g lass. Today, a typical float glass plant can produce about 3000 m2 of hig h-quali­ ty glass every hour. Glass in architecture

The palm houses, railway stations and market halls of the 1 9th century were already able to incorporate fully g lazed facades. The architects of the time were fascinated by the chance to provide their bui ldings with totally transparent external walls. As early as 1 9 1 9, Ludwig M ies van der Rohe put forward a radical design for a total ly glazed high-rise building in Berlin (which was never b u i lt) . The Bauhaus building in Des­ sau (Waiter Gropius, 1 926, fig. B 8.4) is regard­ ed as an early example of a large glass facade. One of the first residential buildings to make use of translucent hollow glass blocks was Pierre Charreau's "Maison de Verre" in Paris ( 1 932 ) . The first ful ly g lazed residential blocks in Ameri­ ca appeared in the early 1 950s (Ph i l i p Johnson and Ludwig M ies van der Rohe) , also glass curtain walls for office buildings, which are still a beloved medium of many architects today.

Glass

Glass products

Pressed glass

Glass fibres

glass brickslblocks glass tiles glass roof tiles

glass for greenhouses profiled glass

Metal composite wired polished plate glass

fusing patterned glass

wired patterned glass

sand-blasting

wired profiled glass

optical fibres

foam glass­

glass fleece

insulating materials

glass cloth

composite laminated safety glass

sheet glass optical glass bent glass

glass-fibre insulating materials

treatment

wired glass

Drawn glass

Foam glass

polished plate glass Surface

Thermal

treatment

treatment

sand-blasting

self-cleaning

toughened safety glass

acid-etching

anti-reflection

heat-treated glass

silk-screen printing

angle-selective

si lk-screen printing

insulating glass

radiation-selective

acid-etching

sound-insulating glass

adaptive

fire-resistant glass

phototropic/thermotropic B 8.2

The oil crisis of the early 1 970s gave impetus to the advance of glass technology; the develop­ ment of double g lazing systems and coatings encouraged the wider use of g lass. One excel­ lent example for a thermal break of great trans­ parency is the pyramid at the Louvre in Paris (fig. 8 8. 1 3) .

Glass as a building material

Glass in the general sense is an amorphous solid made from inorganic raw materials. This amorphous state ensues when a melt cools too rapidly for a crystalline structure to form. We could therefore call glass a sol idified liquid, although this would not be scientifically correct. Isotropy, solidity and thermal behaviour are three special qualities of glass that depend on this state. The constituents of glass for building are defined in EN 572 as silicon dioxide (Si02), cal­ cium oxide (CaO), sodium oxide (Nap ) , mag­ nesium oxide (MgO) and aluminium oxide (AIP3) ' The "normal" g lass accounting for the majority of applications in building consists of 75% silicon dioxide, 1 3% sodium oxide and 1 2% calcium oxide.

Properties

Like all materials, glass absorbs radiation. How­ ever, it does this in a range that is invisible to the human eye and therefore glass appears to be transparent. Glass is hard , resistant to wear and has a h i g h compressive strength (fig . 8 8.3) . An exact tensile strength, however, cannot be determined owing to the great brittleness of this material and the relatively high surface stresses. A decisive factor for the strength is hence the qual ity of the g lass surface. Even immed iately after production, microscopic flaws can appear on the surface whose significance or otherwise cannot be meani ngfully assessed without extensive examination. Furthermore, g lass exhibits the property of non-critical crack propagation. This means that cracks on the sur­ face of the g lass can also propagate even if the glass is not subject to any significant load. The breaking of a pane of glass may therefore not have anything d i rectly to do with the tri g gerin g event. I nterestingly, the high surface stresses in glass enable it to do just the opposite, i . e . to close up damage on the surface, e . g . cracks, to a certain extent. This process depends on the surrounding medium; in water for example, this capabil ity is lost. All these properties mean that the probabi lity of fai l u re must be taken into account when design­ i n g glass for structural purposes. And although g lass is incombustible, its brittleness means that it can accommodate only minor thermal

stresses. Only special fire-resistant glass can withstand temperature d ifferences exceeding 80 K ( 1 50 K in the case of toughened safety glass) . G lass is resistant to almost all chemicals apart from aggressive compounds such as hydrofluoric acid . In addition, ordinary glass surfaces can also be damaged by the alkali ne conditions formed under certain circumstances in hardened cement mortar. Manufacture

The high melting temperature of quartz sand (approx. 1 700°C) can be lowered to 1 2001 600°C when mixed with soda (Nap03) or potash (K2C03) ; fluorspar (CaF2) or sodium sulphate (Na2S04 ) reduce the formation of air bubbles . The semi-liquid glass is given the desired shape by flowing, blowing, pressing, casting or rolling while sti l l hot. G lass manufac­ ture requires enormous amounts of energy and is not environmentally friendly; however, the energy audit can be improved by mixing in bro­ ken g lass (cullet) from the production process and, to a l imited extent, from recycled material. Processing

G lass is cut to the desired size by scoring the surface. To do this, a cutting wheel made from diamond or high-strength steel is dragged over the surface while applying pressure. The pane of glass can be subsequently "snapped" along this l ine. Moistening the cut aids this procedure.

Glass parameters Density

[kg/m3 ]

Compressive strength

[ N / mm2]

> 800

Tensile bending strength

[ N / mm2]

30-90

2490

6-7

Mohs hardness Vickers hardness

[kN/mm2]

4.93 ± 0.34

Modulus of elasticity

[ N / mm2]

7x1 0'

Coeff. of thermal expansion

[ 1 0·6K]

8.4

Thermal conductivity

[W/mK]

0.8

Specific heat capacity

[J/kgK]

0.23

Transformation temperature

[OC]

525-545

Softening temperature

[OC]

7 1 0-735

Processing temperature

[0C]

1 0 1 5- 1 045

B 8.3

B 8.4

B 8.5

85

Glass

Metal oxide

Chemical formula

Iron oxide

FeO, Fe,0 3 FeO, Cr,0 3 Fe,03, CoO

deep blue

NiO

grey-brown

Nickel oxide

Colour

blue-green grey

Manganese oxide

MnO

violet

Copper oxide

CuO

red

Selenium oxide

SeO

pale red

Cobalt oxide

CoO

deep blue

Chromium oxide

Cr,0 3

light green

Silver oxide

AgO

yellow

Gold oxide

AuO

yellow

8 8.6

8 8. 7

There are two ways of fixing g lass: clamping or bolting. The clamping method is generally pre­ ferred because with suitable fixings this results in lower stresses in the glass. If fixin g s with bolts in drilled holes are employed, then it is important to ensure that the glass is mounted without any restraints. Washers help to d istrib­ ute the forces at the fixings over a larger area. Drilled holes and cut-outs must conform to m i n­ imum spacing and rad i i requirements.

can be varied between 1 .5 and 12 mm. The maximum d i mensions of single float glass panes are approx. 3.20 x 6.00 m (fig . B 8.9) . Today, some 95% of all flat g lass is produced by the float glass method . Float glass reheated to 640°C or more can be relatively easily bent over forms made from fire­ resistant material.

Special types of glass for building

Heat-resistant borosilicate g lass for fire-resist­ ant glazing has a higher silicon d ioxide content and in addition contains boron trioxide (BP3) ' Quartz g lass has a high silicon content, is especially heat-resistant, is pervious to ultra­ violet radiation and is ideal for photovoltaic modules. If lead oxide (Pb02) is mixed into the glass melt, this produces lead glass, which owing to its high optical density can b e used for lenses and simi lar optical apparatus. Nor­ mal, "clear" glass generally has a l i g ht green tinge and this can be minimised by reducing the amount of iron oxide (FeO) in the g lass melt to produce "colourless" or extra-clear glass. The use of metals and metal oxides to colour glass (fig. B 8.6) has been known since ancient times. Such oxides are introduced during the melting process and colour the whole body of the glass, not just the surface (body-tinted g lass).

Glass products

As the glass products (fi g . B 8.2) depend upon the production methods, the respective meth­ ods are described below together with their particular features. Float glass

Float glass is a high-quality, clear g lass with a flat surface. It is produced by floating the liquid glass at a temperature of 1 1 OO°C on a large bath of molten tin. Being l i g hter, the g lass floats on the surface, spreads out as far as the edges of the bath and gradually solidifies. So-called top rollers convey the glass out of the bath and at the same time reg ulate the thickness, which 86

Cast glass

Cast g lass, more correctly called rol led g lass, passes through pairs of cooled rollers and it is this process that gives this type of g lass its undulating surface. Like float glass it can also be further processed. It is suitable for applica­ tions such as greenhouses. The rolling process also enables a wire mesh to be incorporated (wired g lass) , which helps bond the glass fragments together in the case of damage. The g lass can also be g iven a pat­ tern on one or both sides (patterned glass) . Wired glass can satisfy the requirements for fire-resistant glaz i n g . Profiled g lass is a special form o f cast g lass. The edges of the glass are bent through 90° during rol ling to form glass channels. This product can carry considerable loads and is available i n standard widths of 232, 262, 331 and 498 mm; flange sizes between 4 1 and 60 mm are possible. Profiled glass provides the chance of producing endless ribbons of glass with horizontal retaining profiles alone (fi g . B 8.5). Glass tiles are cast g lass products available in sizes up to 640 x 7 1 5 mm, also in various col­ ours. They can be used both internally and externally.

8 8.8

Glass fibres and foam glass

G lass fleece and g lass cloth can be used to reinforce flexible sheeting, synthetic resins, screeds and concrete. G lass cloth is suitable as wallpaper and for bridging over cracks. Optical fibres of g lass are used for data transmission and in lighting systems. In accordance with their applications, foam glass (cellular glass) and g lass fibre insulating materials (glass wool) are discussed in the chapter " I nsulating and seal ing" (p. 1 36). Capil­ lary panels such as those used for transparent thermal i nsulation consist either of cellular glass structures, PMMA or polycarbonate (PC). These panels are translucent, approx. 8-40 mm thick and achieve U-values as low as 0.8 W/m2K with a simultaneous solar energy gain (see " Insulat­ ing and sealing", p. 1 40) . Glass ceramics

A temperature change in the glass melt trans­ forms this i nto a crystalline (ceramic) state and enables the production of glass with an espe­ cially low coefficient of thermal expansion. This type of glass is resistant to high temperatures (up to 700°C) and can therefore be used for cooker hobs or oven windows for instance.

Further processing of glass

This i ncludes working the edges, thermal treat­ ment or modifying the surface of the glass by various means. Edge work

There are four q uality grades for working the as­ cut edge (code KG) :

Pressed glass

Hollow glass blocks are produced by pressing two glass halves together. These very hard­ wearing building components can be bonded together with mortar and exhi bit good sound insulation properties. Pressing i s also used to produce transparent glass roofing tiles. All pressed glass products exhibit the typical marks that ensue where the two parts of the press come together.

Arrissed edges (KGS), produced by grinding chamfers. Ground edges cut exactly to size (KMG) in which the dimensions of the glass correspond exactly to the dimensions ordered. Ground edges (KGN) with a matt finish. Polished edges (KPO) have the same surface quality as the pane of g lass itself.

Glass

Thermal treatment (toughened safety glass, heat­ treated glass)

The thermal treatment involves heating the glass to approx. 600°C, then cooling the sur­ face in blasts of cold air, which ind uces a pre­ stress: tension in the core, compression on the surfaces. This type of treatment reduces brittle­ ness, improves crack behaviour and also increases the tensile strength. Toughened or heat-treated glass is therefore used for load­ bearing applications (fig . B 8 . 1 1 ) . One such type of glass is called toughened safety glass because it breaks into small, blunt fragments instead of large, sharp pieces when it breaks. Toughened safety g lass exhi b its a higher bending strength (fig . B 8 . 1 0) and better thermal stabi l ity. If intended for use as over­ head glazing or cladding to an external wal l , it must withstand a heat-soak test (see "The building envelope", p. 1 1 6) . The storage over several hours at approx. 300°C tests the glass for possible inclusions that could lead to failure once the glass is built into the structure. The cooling process is slower in the case of heat-treated glass. Heat-treated g lass has a lower internal stress and it breaks into larger pieces than toughened safety glass. However, in contrast to toughened safety g lass, heat­ treated glass in laminated form possesses a residual load-carrying capacity. Thin panes of glass for aircraft and lighting units are pretreated with a chemical method in an electrolytic bath. This method also creates a prestress and permits loads up to six times higher than normal glass. Surface treatments and coatings

Surface treatments can be for purely aesthetic reasons, but adding a coating to the surface of the glass can also change its properties. Enamelling Enamel is a coloured glass powder that can be melted onto the glass at approx. 700°C. This enables coloured surfaces to be produced which, depending on the thickness of the enamel, can vary from translucent to opaque. Any type of pattern, sign, etc. can be produced as required. The temperature rise during the enamelling process creates a prestress in the glass similar to that of toughened safety glass. Fusing This method involves fusing coloured pieces of glass into the surface of a single pane of glass. Glass treated in this way is suitable for i nterior use only. If required outside, the treated pane must be bonded to a pane of toughened safety glass with casting resin. Obscuring processes The mechanical treatments used are grinding or sand-blasting the surface of the glass. After this treatment the g lass is no longer transparent and has a matt appearance (fig . B 8.8). Certain areas can be masked in order to create pat­ tems as required. Etching with hydrofluoric

acid has a similar effect, but surfaces treated in this way do not attract so much d ust and d irt as sand-blasted or ground surfaces. Engraving is suitable for intermittent obscured portions. Silk-screen printing Silk-screen printing is used for decorating areas of g lass. Transparent, coloured surfaces and any form of decoration are possible (fi g . B 8 . 7 ) . Self-cleaning glass I n order to gain the maximum benefits from g lass in energy terms and to reduce the cost of cleaning the g lass, glass with self-cleaning sur­ faces has been on the market for a number of years. A coating of polymers prevents the for­ mation of water droplets and this prevents d i rt and dust adhering after the water has evapo­ rated (hydroph i l i c effect) . Other coatings func­ tion in a similar manner: the hydrophobic prin­ ciple uses a microscopically coarse structure to prevent the formation of a film of water (Lotus Effect) , and a photocatalytic coating breaks down organic residues with the help of the inci­ dent solar radiation. I n doing so, catalytic rad i ­ cals are formed in a chemical reaction and these destroy biological structures.

Max. producPermissible deviations tion size; side thk. side length x width length length < 2000 mm > 2000 mm

Nom. thk.

[mm]

[mm]

[mm]

[mm]

3

0.2

2

3

4500 x 3 1 80

4

0.2

2

3

6000 x 3 1 80

5

0.2

2

3

6000 x 3 1 80

6

0.2

2

3

6000 x 3 1 80

8

0.2

2

3

7500 x 3 1 80

10

0.3

3

4

9000 x 3 1 80

12

0.3

3

4

9000 x 3 1 80

15

0.5

5

6

6000 x 3 1 80

19

1

5

6

4500 x 2820

[mm]

B 8.9

Heattreated

Tough. safety

Property

Float

Ult. bend, strength

45

70

1 20

12

29

50

Max. permissible temp. 40

1 00

1 50

2.5

2.5

[ N /mm'} Max. bending strength [ N/mm'}

gradient [K} Density [g/cm3}

2.5

Cutting ability

Optically effective coatings Anti-reflection coatings reduce the reflection from the g lass surface. There are two ways of doing this. In one method several thin layers are applied to the glass and the effect of these is to cancel out the reflected radiation by means of i nterference. Such coatings can be applied for selected wavelengths. In the other method microscopic structures embossed in a layer of synthetic material reduce the refractive index of the glass. In contrast to the first meth­ od, such microscop i c surfaces work particular­ ly wel l at shallow i ncident angles. And the total incident solar energy is able to pass through the g lass. Dichroic coatings break up the incoming l i g ht at the surface of the g lass and allow the pane to shine i n various colours - based on interfer­ ence effects.

Failure behaviour

radial cracks emanat- dice-like­ ing from failure point

struct. B 8. 1 0

B 8.6

Metal oxides for body-tinted glass

B 8.7

Glass with silk-screen printing, health spa admin.

B 8.8

Acid-etched glass, art gallery, Bregenz, Austria,

B 8.9

Nominal thicknesses, permissible deviations and

building, Bad Elster, D , 1 999, Behnisch & Partner 1 997, Peter Zumthor maximum pane sizes for float glass B 8. 1 0 Comparison of the physical parameters of float, heat-treated and toughened safety glass B 8 . 1 1 Glass beams made from laminated safety glass, sunshading by means of baked-on ceramic ink, Museum of Glass, Kingswinford, UK, 1 994, Design Antenna

Laminated glass

The bonding of float, toughened safety or heat­ treated g lass over its full area opens up further possibilities for the use of glass regarding: • • · •

safety sound insulation fire protection visual design

Laminated safety glass

Lami nated safety glass is produced by bond­ ing together up to six panes with polyvinyl butyl (PVB) film. This transparent film binds the frag­ ments of glass together in the case of break­ age and ensures a certain residual load-carry­ ing capacity. Applications range from loadB 8. 1 1

87

Glass

Outside

Reflectio

coatings B 8 . 1 3 Louvre Pyramid, Paris, France, 1 989, B 8 . 1 4 Comparison of heat-absorbing and solar-control glazing B 8 . 1 5 Adaptive glass, "R 1 29" Project, Werner Sobek

III

J � U � I 11 I

Emission + convection

B 8. 1 2 Schematic diagram of position and effect of

leoh Ming Pei

Light permeability

======�>

-..___==>

___

1

1 2 3 4

0

Inside

Transmission

Emission

+ convection

2 3 4

Surface coating Low-e coating for thermal insulation Low-e coating for sun protection Surface coating B 8. 1 3

B 8.12

bearing (fig . B 8. 1 1 ) to bullet-resistant glazin g depending on t h e thickness. Fire-resistant glass

The use of aqueous gel layers as the interlayer instead of PVB film results in laminated fire­ resistant g lass. A rise in temperature causes the gel to foam up, which makes it opaque and therefore able to absorb heat radiation. D I N 4 1 02 d isting uishes between G-glass, which reduces the heat radiation by 50%, and F­ g lass, which must limit the temperature rise to 1 40 K on the side not exposed to the fire. Film interlayers

The use of, for example, printed polyethylene (PE) films i nstead of the PVB i nterlayer req uired for laminated safety g lass leads to further design options for architects. Very h i g h q uality printing is possible in any colour and any inten­ sity from transparent to opaque. This technique is limited only by the width of the films availa­ ble. Casting resin represents an alternative for bonding panes together. It is also possible to use laser imag i n g to create holographic optical effects. Like optical devic­ es such as lenses etc . , holographic optical ele­ ments (HOE) can generate specific red irection, refraction or shading of the incom i n g light.

Insulating glass

I nsulating glass consists of at least two panes on either side of an insulating layer of gas pre­ vented from escaping by a hermetic edge seal. Such composite glazing units improve the ther­ mal and sound insulating properties. All the types of glass described above can be com­ bined to form insulating glass elements. Further division of the cavity between the panes by means of extra glass panes or separating films can improve the insulating properties of the glazing still further. The cavity is generally between 8 and 20 mm wide. The hermetic edge seal must be designed according to the requirements of the gas fil l i n g . The g lued metal edge seal most commonly used consists of a double seal, a metal spacer and an integral dessicant.

88

Thermal insulation

I n comparison with s i n g l e g lazing, insulating glazin g achieves substantially better thermal insulation values. In physical terms, the heat transfer through the composite g lass unit involves three d ifferent processes: •

•

•

Convection, i .e. energy transfer by means of gas movements in the cavity Transmission, i .e . energy transfer by means of radiation Heat conduction in the g lass, g lass compos­ ite and cavity

Gas fillings Noble gas fillings such as argon, xenon or krypton improve the thermal i nsulation; com­ pared with air they lower the U-value (fi g . B 8 . 1 4) . Such heavy gases reduce the effects of convection and transmission in the cavity. Although xenon and krypton exhi bit better ther­ mal properties, argon is generally used owin g t o its ready availability a n d the simpler produc­ tion process. Vacuum Creating a vacuum in the cavity enables the heat conduction to be reduced even further. This requires a vacuum of about 1 0-3 bar in the cavity. The insulating effect of the vacuum does not depend on the spacing of the panes, which renders possible cavities < 1 mm wide. Howev­ er, as the vacuum causes the panes of glass to deflect inwards, spacers are necessary to pre­ vent them touching and hence negatin g the insulatin g effect. Coatings Metallic coatings of silver or titanium influence the reflective and absorption behaviour of the g lazing. The aim is to reflect the majority of the infrared radiation that is re-emitted out of the building. Such coatings reduce the emissivity and are in principle suitable for solar control and thermal i nsulation purposes. The spectral emissivity denotes that part of the transmission that penetrates a body by way of thermal emis­ sion. The emissivity of float glass is 0.89. There are three ways of applying such coat­ ings. In the online method a layer of metal

oxide is appl ied to the hot surface of the g lass d uring the manufacturing process. The offline process (including sputtering) involves coating the finished pane of g lass. A coating produced in this way is less durable than an online coat­ ing and is therefore immediately incorporated in an insulating glazing unit. The physical vapour deposition (PVD) method allows the coating material to condense on the glass. Heat-absorbing g lass coated with silver is known as low-e ( low emissivity) glass and represents the current state of the art. These days, such g lass can be produced practically without any colour. A low-e coating can cut the U-value of a glass pane from 3.0 to 1 .6 W/m2K. As the position of the coating influences the effect of the insulating g lazing (fig. B 8 . 1 2 ) , the g lazing units must be suitably marked to ensure that they are installed correctly. =

Heat-absorbing insulating glass This i s an i nsulating unit with at least one heat­ absorbing coating . It is normal for a heat­ absorbing double g lazing unit to achieve U-val­ ues of 1 .0-1 . 1 W/m 2K. Triple-glazed units with a noble gas fi lling and two low-e coatings can achieve U-values as low as 0.4 W/m2K. Solar-control glass

A reflective coating on the outer pane can lower the U-value considerably, improve the energy transmittance and hence contribute to controlling the amount of solar radiation enter­ ing a building. The type of reflection can range from simple mirroring to selective coating (e. g . inverse low-e coating ) . A s c a n be seen from fig. B 8. 1 4, it is necessary to check the colour rendering of the g lass when using solar-control coatings. Angle-selective coating Metallic coatings with a optical refraction behav­ iour dependent on angle represent a new devel­ opment. A m icroscopically small prismatic structure refracts the incoming light depending on the angle of incidence. Such coatings pre­ vent solar glare, but must be produced specifi­ cally for the location and the corresponding angle of incidence.

Glass

Solar-control glazing

Heat-absorbing glazing

Technical values of various insulating glazing units

Dimensions (pane/cavity/pane) [mm]

Double glazing,

Triple glazing,

Double glazing,

one pane coated

two panes coated

one pane coated

4-1 5-4

4-1 2-4-1 2-4

6-1 6-4

normal emission ,; 0.05

6-1 6-4 colourless 1

6-1 6-4

normal emission ,; 0.05

Argon

Argon

Argon

Air

Cavity filling (gas concentration ;, 90%)

Argon

Krypton

Argon

Krypton

blue 1

green

1

Uo

[W/m2K]

1 .5

1 .2

1 .1

0.8

0.5

1 .1

1 .1

1 .1

g

[%]

64

64

64

52

52

37

24

28

Light permeability 1

TL

[%]

81

81

81

72

72

67

40

55

Light reflection

RL

[ %]

12

12

g

14

14

1 1 /1 2 2

1 0/33 2

9/ 1 2 2

Ra

[%]

98

98

98

96

96

96/94 2

95/70 2

86/88 2

U-value to EN ISO 1 0077-1 Total energy transmittance

1

1

Colour rendering 1 1

Typical manufacturers' data

2 Values valid for inside/outside B 8.14

Adaptive glazing Variable coatings will be available for further applications in the future, particularly for intelli­ gent facades (fig. B 8. 1 5) . These coatings change - either automatically or by using suit­ able controls - from a light- and rad i ation-per­ meable to a light-deflecting, shading or reflect­ ing state. Electrochromic coatings consist of an approx. 1 mm thick polymer film containing certain metal oxides such as tungsten oxide (W0 ) , 3 nickel oxide ( N iO) or iridium oxide ( I r0 2) . The total energy transmittance of the glass is reg u­ lated by applying an electric current, which switches the glass between a transparent and a deep-blue state. After switching off the cur­ rent the latter state remains for a limited period (1-24 hours) . The coating achieves a reduction in the energy transmittance of max. 20%. Elec­ trochromic g lass is suitable for shading and anti-glare appl ications. Liquid crystals can be aligned upon applying an electric current and therefore switched from a light-scattering, non-transparent state to a transparent state. However, owing to their sen­ sitivity to temperature, liquid crystals have so far only been used internally for variable priva­ cy screens. Micro-encapsulated liquid crystals, which create a minimal obscuration of the glass, can vary the l i g ht transmission value between 0.48 and 0.76. Gasochromic g lazing represents yet another development. A coating of tungsten oxide (W0 ) changes to a blue colour due to an inlay 3 of catalytically generated hydrogen and loses this colour again when air is introduced. The coating enables the light transmission value to be varied between 1 5 and 60% . A gas supply capable of regulating an area of up to 1 0 m2 is required for operation. Phototropic and thermotropic g lasses do not require any form of control. The variabil ity of the phototropic glass is based on metal ions (e.g. silver ions) and the glass is regulated depend­ ing on the ultraviolet radiation. Thermotropic glass is based on a mixture of two substances that segregate above a certain temperature. The glass then scatters the incoming light and appears translucent.

Fittings in the cavity Glazing with rigid or movable fittings in the cav­ ity between the panes can satisfy further requirements with respect to thermal insulation, shading and aesthetics. However, it should be remembered that external pressure conditions d uring certain types of weather can cause the panes to deflect. It is therefore necessary to g uarantee sufficient clearance between the fit­ tings and the g lass. Light redirection, sunshading, anti-glare provisions Rigid or movable - with electric or mechanical drive - aluminium louvres can be fitted in the cavity. The surface of the louvres can be opti­ mised to red i rect the light; for instance, rigid reflective louvres are often triangular in shape with each side having a concave form. The incoming l i ght causes no glare provided the geometry has been chosen correctly; however, an unobstructed view through the window - in either direction - is no longer possible. Retro-Iouvres are very sma l l , folded, rigid blinds. Thanks to their ingenious geometry, they enable a good view through the window, achieve good light-redirection characteristics but also provide shad i n g . Besides movable a n d r i g i d systems i n the cavi­ ty, it i s also possi ble to i nstall any material whose degree of perforation determines the

energy transmission a n d t h e view through the window. The possibil ities are almost limitless: perforated sheet metal, woven metal meshes, wooden bars, etc. Sound insulation

Heavy gases, e . g . sulphur hexafluoride (SF6) , argon and krypton, also improve the sound insulation properties of i nsulating glazing com­ pared to a filling of air. The following parame­ ters can also improve sound insulation: • •

·

·

heavy panes (high inertia) different pane thicknesses (avoidance of resonance effects) inclusion of PVB films (mass-spring-mass principle) wide cavity

B 8.15

89

Synthetic materials

B 9. 1

B 9.1

The production of synthetic materials began in the middle of the 1 9th century with the chemi­ cal conversion of natural , organic raw materi­ als. Following an experimental phase, it became possible to improve specific properties of the materials in such a way that it was gradually possible to replace trad itional products. The chemical cross-linking (vulcanisation) of rubber­ latex from the rubber tree to form rubbery elas­ tic natural rubber marked the beginning of the rubber industry. Cellu loid , a conversion product made from nitrocellulose and camphor, is regarded as the first thermoplastic material. It was used as a transparent backing for the l i ght-sensitive lay­ ers needed for photography. U p until the end of the 1 9th century the produc­ tion of these synthetic products required regen­ erative raw materials. A chemical analysis reveals the carbon atom in the molecules to be the central, common element, which is added together to create the long chains that form the foundation for the structure of organic products. The application of this knowledge led in 1 898 to the production of the first ful ly synthetic mate­ rial from a combination of phenol (obtained from coal tar) and formaldehyde. Without fillers, phenolic resin is as clear as g lass. But mixed with fi l lers and pressed into moulds at high temperatures it provided the emerg ing electrical industry with a heat-resist­ ant, non-meltin g , non-conductive material for housings and insulation. This, the first thermo-

setting plastic, first appeared in 1 909 and was called Bakelite. Fundamental to the production of plastics is the fact that individual low-molecular units (mono­ mers) combine under suitable conditions to form macromolecules (polymers) in a chemical reaction known as synthesis. By 1 940 the plastics industry had devised methods for the large-scale production of most of the plastics we know today. The numerous combination options of various units and the further processing result in tailored materials such as foamed plastics, synthetic fibres or composites. These synthetic materials were i nitially used in the electrical engineering and automotive industries, but started to appear in the building industry from the 1 960s onwards - also for larger components. Since then, architects have dem­ onstrated the efficiency of synthetic materials for load bearing shell structures, facade clad­ ding or, for example, the translucent panels to the roof of the Olympic Stadium in Munich (fig . B 9. 1 ) . Today, synthetic products can be found in all branches of building ; either exposed e . g . as a floor covering or facade element, or con­ cealed, e . g . as waterproofing sheeting, insula­ tion or building services.

B 9.2

B 9.3

Tent roof covered with PMMA panels, Olympic Stadium, Munich, Germany, 1 972, Gunter Behnisch + Partner, Frei Olto and others

B 9.2

"Blow" PVC armchair assembled using seam welding, Italy, 1 967, Carla Scolari, Donato D'Urbino, Paolo Lomazzi, G ionatan d e Pas

B 9.3

"Connexion skin", pneumatic balloon made from PVC film assembled using seam weldin9, Austria, 1 968, Haus-Rucker-Co

B 9.4

Youth centre, Gironde, France, 1 994, Lacaton & Vassal

90

Synthetic materials

Chemical structure of synthetic materials

The fossil raw materials petroleum, natural gas and coal were formed by the decomposition of organic substances. Over m i l l ions of years, carbon (C) and hydrogen (H) accumulated on the seabed under the action of heat and pres­ sure. Petroleum consists of hydrocarbon molecu les whose boiling point rises as the length of the chain increases. The d istillation of petroleum in the refinery separates the molecular chains with their different lengths into ind ividual frac­ tions such as gas, petrol, diesel and heavy o i l . In the so-called cracking process unsaturated - and hence reactive - hydrocarbons are pro­ duced from the lightweight petrol (naphtha) obtained in the d istil lation process. Those hydrocarbons include the low-molecular gases ethylene and propylene, which are the most important raw materials for the manufacture of synthetic materials. Today, they can also be obtained from regenerative raw materials but only at great cost. Besides carbon and hydrogen, synthetic mate­ rials - depending on type - contain further chemical elements such as oxygen (0) , chlo­ rine (Cl ) , fluorine (F) , sulphur (S) , s i l i con (Si) and nitrogen ( N ) . Features

The following features are characteristic of the majority of synthetic materials, even if their properties are sometimes very specific: low density, low thermal conductivity, high coeffi­ cient of thermal expansion, high tensile strength, low modulus of elasticity, narrow con­ tinuous service temperature range, good elec­ trical insulation capabil ity, resistance to water and many chemicals, inflammabi l ity, ageing caused by ultraviolet radiation (unless add itives are used), brittleness at low temperatures.

Homopolymers consist of identical monomers, e . g . polyethylene (PE) , polystyrene (PS) or poly­ vinyl chloride (PVC). Copolymerisation i s the reaction between d is­ parate monomer units, which enables the prop­ erties of the synthetic materials to be varied even further. Copolymers with linear macromol­ ecules include, for example, styrene acryloni­ trile (SAN) and styrene-butadiene rubber (SBR). Step polymerisation Step polymerisation is achieved through the reaction of monomers with reactive groups usually hydroxyl (-OH) or amino groups (-NH2) - to form macromolecu les. In doing so, low­ molecular molecules, usually water (HP) , are given off. The reaction is based on an equilibri­ um, which allows the reaction to be controlled. Step polymers with l i near macromolecu lar structures are, for example, polyamide (PA) , polycarbonate (PC) and polyester (PET) , those with a cross-l inked structure include, for exam­ ple, phenol-formaldehyde resins (PF) . Chain polymerisation The basic principles of chain polymerisation are very similar to those of step polymerisation: different monomers form macromolecules through reactive groups; however, in this case without g iving off low-molecular by-products. The ensuing products are classified according to their chemical structure, e.g. as polyurethanes (PUR) or epoxy resins (EP).

The so-called polymer blends or alloys occupy a special position. These are blends of at least two complete thermoplastics, the aim being to benefit from the properties of both polymers, e . g . ABS + PC. Classification according to the macromolecular structure

The diverse range of synthetic products can be classified according to the method of synthesis or according to the molecular structure. Both forms of classification allow conclusions to be drawn regarding the nature of the raw materials used and the mechanical-thermal properties of the product.

I rrespective of the method of synthesis, there are three groups of synthetic materials classi­ fied according to the structure of the ind ividual macromolecu les and hence the possible arrangement withi n the polymer microstructure (fi g . B 9 . 7 ) . The degree of cross-l inking between the macromolecu les, which i nfluences

the fundamental properties of the synthetic materia l , is the governing criterion for this clas­ sification. Thermoplastics The macromolecules of the amorphous thermo­ plastics, e . g . polymethyl methacrylate (PMMA) , consist of l i near molecular chains that tangle around themselves but do not form any chemi­ cal bonds with each other. Amorphous thermoplastics are as transparent as glass and hard and brittle at room tempera­ ture. Partially crystalline thermoplastics such as polyamide (PA) also exhi b it orderly, so-called crystalline, regions in addition to the tangled reg ions, which contribute to the better strength of such materials. As the degree of crystallisa­ tion increases, so the transparency decreases. Physical bonding forces hold the macromole­ cules together. As the tem perature rises, so the bonding forces decrease and the flexibility of the i n d ividual chains increases, which allows the properties of the thermoplastics to gradually change from hard to thermoelastic to thermoplastic. The process ( e . g . melting) is reversible and can also be achieved with certain solvents. It is this characteristic that al lows the thermoplastics to be readily mou lded, machined and recycled. Elastomers Elastomers consist of cross-linked low-density molecular chains. Upon forming they are joined together chemically (vulcanisation) and cannot be separated again by applying heat, and therefore cannot melt. Solvents cause them to swell up. At service temperatures elastomers exhi bit a rubbery elastic behaviour and break down irreversibly at certain temperatures, e . g . elastomers o n the basis o f styrene-butadiene rubber (SBR). Thermoplastic elastomers (TPE) such as PUR or SBS block copolymers have similar proper­ ties to elastomers. However, they exhi b it physi­ cal i nstead of chemical cross-linking and can thus be processed l i ke thermoplastics. Thermosets The high-density, three-dimensional cross-link­ ing characteristic of thermosets comes about

Classification according to the method of synthesis

We distinguish between three methods for pro­ ducing synthetic materials. In these processes reactive monomers are combined through chemical reactions to form chain-like, branch­ ing or cross-linked macromolecules. Polymerisation Pressure, heat, light, initiators and catalysts ini­ tiate the polymerisation. The covalent bonds of the monomers break up and the i n d ividual units combine to form l i near molecular chains with­ out giving off any by-products. The external conditions influence the length of the chain and the degree of interlocking among the molecular chains.

B 9.4

91

Synthetic materials

as they are formed with pressure, heat or hard­ eners. After forming, the i nfusible thermosets can only be machined. They are hard and brit­ tle, insoluble in organic solvents and have the highest thermoforming resistance of the three groups of plastics. Their mechanical properties improve in conjunction with fibres or fillers. Reaction resins such as epoxy resins (EP) , polyurethane resins (PUR) and unsaturated polyester resins (UP) in the form of casting res­ ins or moulding compounds form the basis (matrix) for fibre composites.

a

Processing

The manufacture of monomers and their further processing to form polymers is carried out on a large industrial scale. This i n dustry supplies the pure synthetic materials in the form of granular material (pellets) to the product manufacturers. These then mix add itives homogeneously into the synthetic materials in the so-called com­ pounding process. Afterwards comes the form­ ing process to form the semi-finished or final product.

b

Additives

Besides the degree of polymerisation (length of chai n), degree of crystallisation and degree of branching/cross-linking of the synthetic mole­ cules, it is the additives that have a considera­ ble i nfluence on the properties of the synthetic materials.

B 9.5

Macromolecular structures of synthetic materials: a Tangling in amorphous thermoplastics b Low-density cross-linking in elastomers c High-density cross-linking in thermosets

B 9.6

Polycarbonate rooflights used as a facade ele­ ments, ads 1a gallery, Cologne, Germany,

2002,

b & k+

B

9.7

Systematic classification of synthetic materials according to macromolecular structure and method of synthesis

Fillers Fillers in the form of particles, fibres or beads made from organic or inorganic substances are used in thermosets as extenders, for i mproving the surface finish and for reducing the brittle­ ness. They can also influence the flowin g prop­ erties and the shrinkage of thermoplastics. The industry uses fillers such as cellulose, wood d ust, stone dust, chalk, kaolin or g lass beads . Reinforcing materials Reinforcing materials are used to improve the rigidity, strength and thermoforming resistance. Glass fibres (GF) , carbon fibres (CF) and ara­ mid fibres (AF) reinforce the synthetic materials in the form of meshes, non-woven fabrics or rovings in roofl i ghts, waterproofin g , vessels or pipes. Colorants I nsoluble colorants (pigments) dye the whole body of the synthetic material opaque. Soluble colorants are used in transparent, dyed syn­ thetic materials. Stabilisers The add ition of stabilisers can help to counter­ act the damage sometimes caused by heat, light and ultraviolet radiation. Besides its use as a pigment, carbon black also increases the UV­ radiation stability of many synthetic materials.

B 9.6

92

Plasticisers Plasticisers i ncrease the flexibility and hence also the impact toughness. Hard and brittle synthetic materials can thus be transformed into flexible materials. We distinguish between two types of plasticisation: external plasticisa­ tion is achieved by adding viscous, Iow-molec­ u lar substances which slip between the molec­ ular chains of the synthetic material , reduce the physical attraction forces and thus increase the flexibility of the molecular chains. As in this case the plasticiser is not chemically bonded with the synthetic material, in principle it can leach out, or be exuded, or over a long time in contact with another synthetic material can m ig rate to this other material. The original syn­ thetic material thereby loses its flexibility and becomes brittle. I nternal p lasticisation increases the spacing of the molecular chains chemically through copoly­ merisation and therefore increases the flexibility of the chain segments. I nternal plasticisation is virtually inert to external effects. Flame retardants The objective of flame retardants is to reduce the combustibility of synthetic materials. I n physical terms they bring about cooling o r pro­ vide a coating in the event of a fire, or - in chemical terms - form a layer of ash, or prevent the oxidation of combustible gases. Blowing agents Blowing agents create foams from synthetic materials. In the foaming process, blowing agents such as hig hly volatile fluids or com­ pressed gases are allowed to expand. In the chemical foaming process chemical reactions form gases (blowing agents) which then expand the polymers. Non-halogen blowing agents are now standard (see " I nsulating and sealing", p. 1 37 ) . Forming methods

The initial form i n g of semi-finished products or moulded parts from the basic synthetic materi­ als in powder, pellet or liquid form is known as "primary forming". In the case of thermoplastics the forming process is reversible owing to the physical entanglement. The melted pellets retain their form and cool down to the solid state. In thermosetting polymers a chemical cross-linking takes place during the irreversible forming process during which the thermoset­ ting properties ensue. Elastomers are irreversi­ ble after the forming process, but have a low­ density cross-linked structure produced by, for example, vulcanisation (fig . B 9.5) . Extruding The extruder turns the liquid thermoplastic syn­ thetic compound into PVC, PE, PM MA or PC sections, profiles, p ipes, boards, sheets, films, tubes and hoses in a continuous process. In a second stage, e . g . blow moulding, a section of tube, for instance, can be blown into a negative mould before cool i n g .

Synthetic materials

Synthetic materials

Thermoplastics,

Thermosets,

no cross-linking

high-density cross-linking

Polymerisation

Step polymerisation

Step polymerisation

Chain polymerisation

Polyolefins:

Polyamides (PA)

Aminoplasts:

Cross-linked poly­

Elastomers o n the basis

Polyurethane­

polypropylene (PP)

Polycarbonate (PC)

urea-formaldehyde resins (UF)

urethanes (PUR)

of:

elastomers (TPU)

styrene-butadiene rubber

Polyester elastomers

(SBR)

(TPC)

polyethylene (PE)

melamine resins (MF)

high-density

Linear polyester:

melamine-phenolic resins (MP)

polyethylene (PE-HO)

polyethylene terephtha­

resorcinol resins (RF)

butadiene rubber (BR)

Iow-density

late (PET)

& blends

chloroprene rubber (CR)

Epoxy resins (EP)

polyethylene (PE-LD) polyisobutylene (PI B)

Chain polymerisation

Elastomers on

isobutylene-isoprene

polyolefin basis:

Phenoplasts:

rubber / butyl rubber ( I I R)

ethylene-vinylacetate

phenolic resins (PF)

chlorosulphonated poly­

copolymer (EVAC)

Polyvinyl chlorides (PVC):

ethylene (CSM)

unplasticised (PVC-U)

Linear polyurethanes

Unsaturated polyester resins

ethylene-propylene-diene

plasticised (PVC-P)

(PUR)

(UP)

rubber (EPOM)

Polystyrene (PS) expanded polystyrene

Copolymerisation

(EPS)

Semi-synthetic materials Ethylene-tetrafluoro­

Polysulphone (PSU)

ethylene copolymer (ETFE)

Polyoxymethylene (POM)

Ethylene copolymer

Polyacrylonitrile (PAN)

bitumen (ECB)

Polymethyl methacrylate

Styrene acrylonitrile (SAN)

(PMMA)

Acrylonitrile-butadiene­

Silicones (SI) (polysiloxanes)

Polytetrafluoroethylene

styrene copolymer (ABS)

Nitrocellulose (CN)

Vulcanised

(PTFE)

Polyvinyl acetate (PVAC)

Cellulose acetate (CA)

fibres (VF)

Natural rubber (NR)

B 9. 7

Ca/endering A succession of rolls can turn thermoplastics or rubbers into sheet material. During this process it is also possible to profile the surface and incorporate a textile inlay. Floor coverings and waterproofing sheeting made from PVC or poly­ olefins can be produced using this method . Injection moulding The mass production of articles - but also small moulded parts - made from thermoplastics, thermosets and elastomers is possible with in­ jection moulding. The synthetic material is in­ jected into moulds under high pressure where it cools or cures. This method can also be used to interlock several plastic components. Pressing The moulding compound made from thermo­ setting resins is poured into the die and com­ pressed at a high temperature so that the molecular chains cross-link to form a thermo­ set. A lamination press is used for manufactur­ ing facings for boards and panels from backing sheets saturated with thermosetting resin. Thick-walled panels or foamed semi-finished products made from PS or PP (thermoplastics) are obtained by cooling after pressing. Rotational moulding Almost all thermoplastics are suitable for rota­ tional moulding . Rotation causes the fluid syn­ thetic compound to spread over the outside of the mould, which is rotated about various axes. This method is used to manufacture recepta­ cles for transport and storage.

Plastic forming Only semi-finished products made from ther­ moplastics (e. g . panels, sections, pipes) are suitable for plastic forming. Once heated to a suitable temperature they can be bent, stretch­ formed in a vacuum or deep-drawn. However, the new shape must be maintained until the product has fully cooled, otherwise the part returns to its former shape. Jointing Only semi-finished products made from ther­ moplastics (e.g. panels, sections, pipes) are suitable for plastic forming. Once heated to a suitable temperature they can be bent, stretch­ formed in a vacuum or deep-drawn. However, the new shape must be maintained until the product has fully cooled, otherwise the part returns to its former shape. Health hazards

Fully processed, pure synthetic materials are harmless when used properly. Even the manu­ facture, further processing or installation of syn­ thetic materials does not represent an increased health risk when carried out properly and pro­ vided the numerous reg ulations of the authori­ ties, e . g . the limits for concentrations of sub­ stances in the air or the technical directive for hazardous substances, are adhered to. Toxic compounds such as dioxins or furans can ensue during a fire. The halogen com­ pounds often used as flame retardants in some synthetic materials contribute to this problem (see "Glossary", p. 268 ) .

Recycling

The plastic waste that occurs during produc­ tion is generally returned to the material lifecy­ cle because it satisfies the conditions for reus­ ing the material: it is pure, clean and has not yet aged. There is no need for a complex and expensive collection system. There are basically four options for recycling plastic waste: Reusing the products Identical components in large batches plus compatibil ity guaranteed through standardised forms and dimensions ease the reuse of plas­ tics. This i s the case, for example, with returna­ ble bottles or moulded parts for the automotive industry. In the building industry only PVC win­ dow frames have been reused to date, and this only on a small scale. Enormous potential lies in expanding this system to include other com­ ponents such as facade panels or insulation by employing standardised sizes. Reusing the materials This involves the mechanical preparation of used plastics to form directly reusable ground materials. The chemical structure remains unal­ tered during this process. Viable reuse of synthetic materials requires an abundance of clean, sorted, plastic scrap cou­ pled with minimal logistics requirements. This is the case, for i nstance, with commercial p lastic waste or PVC windows and pipes from private household s . As a rule, the reuse of materials leads to a loss of q uality.

93

Synthetic materials

Reusing the raw materials To do this it is necessary to break down the polymer chains of the synthetic materials using heat and solvents. The ensuing prod ucts are petrochemical su bstances such as o i l s and gases which can be used to manufacture new synthetic materials or even for other purposes. This method also works with unsorted , soiled plastic waste. Reusing for energy purposes Plastics scrap and waste containing plastics have a high calorific value owing to their high carbon content. If they are unsuitable for recy­ cling processes to extract the materials or raw materials, they may be burned instead of fossil fuels for energy generation in appropriate incin­ eration plants. Thi s is frequently a rational option from both the ecological and economic viewpoints.

Synthetic materials in building

Alongside the packagings industry, the build­ ing industry is one of the most important cus­ tomers for products made from synthetic mate­ rials, accounting for about 20% of the output of the plastics industry. A selection of the synthetic materials used in building is given below, arranged in the order thermoplastics , thermo­ sets, elastomers and composite systems. Fig. B 9 . 1 3 l ists possible applications.

8 9.8

U n plasticised PVC (PVC-U) is hard and brittle. The add ition of plasticisers modify the material to form p lasticised PVC (PVC-P). PVC can be manufactured in clear transparent, coloured transparent or opaque forms. It does not ignite easily and burns only with difficulty owing to its high chlorine content. Polystyrene (PS) - thermoplastic

Polystyrene is clear l ike glass, has a high sur­ face gloss and is relatively brittle. Only by add­ ing UV-radiation stabilisers does it become hardweari n g . Solvent-based adhesives achieve a good joint by partly d i ssolving the surface. Foaming produces expanded (EPS) or extrud­ ed (XPS) polystyrene, both of which are wel l known a s thermal and sound insulation materials.

Polymethyl methacrylate (PMMA) - thermoplastic

Better known by its trade names, e . g . Perspex, this material has very good optical qual ities and a high scratch resistance. In many instanc­ es it can be used as a substitute for glass. Its high coefficient of thermal expansion must be taken into account, and unrestrained changes of length must be possible in the installed con­ dition. The following products are made from PMMA: clear transparent and coloured sheets, double-walled panels, rooflights and splinter­ proof panes. Polymers containing fluorine (PTFE/ETFE) thermoplastics

Polytetrafluoroethylene (PTFE) and ethylene­ tetrafluoroethylene copolymer (ETFE) both

Polyethylene (PE) - thermoplastic

Polyethylene is one of the polyolefins and con­ sists entirely of hydrocarbons. We d istinguish between high-density (PE-HO) and Iow-density (PE-LD) polyethylene. Polyethylene is an inex­ pensive, easily worked plastic and comes in forms from rigid to soft depending on the degree of crystallisation and polymerisation. In the form of a thin film, polyethylene is almost as clear as glass, but otherwise has a m i l ky white appear­ ance. It can be dyed any colour and i s very easy to join by wel d i n g . The applications in build ing i nclude drinking water and waste water p i pes, sheets for waterproofing and protecting, and floor coverings (see "Floors", p . 1 81 ) . Polypropylene (PP) - thermoplastic

The properties and applications of polypropyl­ ene - also one of the polyolefins - are similar to those of polyethylene. This synthetic material resists ageing without additives. Owing to its particularly high chemical resistance, its adhe­ sive qualities are poor. Polyvinyl chloride (PVC) - thermoplastic

The outstanding properties of PVC such as chemical resistance, mechanical strength, mul­ tiple machining options and adjustability with regard to flexib i l ity and impact toughness make it suitable for use in many areas, e . g . waste water p i pes, window frames, rooflights, corru­ gated sheets, facade elements, waterproofing and floor coverings. 8 9. 1 0

94

Synthetic materials

B 9.8

Coloured paper laminated with melamine resin, private house, Bad Waltersdorf, Austria, 2004, Splilterwerk

B 9.9

Translucent corrugated PVC sheets, workshop, Madrid, Spain, 2004, Garcia Abril

B 9. 1 0 "Falter", National Garden Exhibition, Kassel , Ger­ many, 1 955, Frei Olto B 9.1 1 Glass fibre-reinforced polyester resin, Forum Soft Pavilion, Yverdon-Les-Bains, Switzerland, 2002, Team Extasia B 9. 1 2 Glass fibre-reinforced polycarbonate, canopy, Kassel, Germany, 2005, Hegger Hegger Schleiff B 9.13 Possible applications for synthetic materials according to consumption (selection)

exhibit excellent chemical resistance. They are l ight-fast without the addition of UV-radiation protection, virtually self-cleani n g , exhibit excel­ lent thermal stability and incombustible. How­ ever, they are hydrophobic (and that makes them difficult to bond with adhesives) . Pneu­ matic, translucent constructions often make use of ETFE film, whereas PTFE is processed to form membranes in conjunction with textiles or as a coating to textiles. Epoxy resins (EP) - thermosets

The addition of a hardener causes the fluid or viscous molecules of the epoxy resins to cross­ link and form a thermosetting material. The strength and impact toughness varies depend­ ing on the fillers used, the degree of cross-link­ ing and whether fibre reinforcement has been incorporated. Coatings, adhesives and fibre composites are produced from epoxy resins.

B 9. 1 1

B 9. 1 2

adhesives for joining glass, metals, ceramics and plastics can be made from s i l i cones.

shells) make u s e of reinforcement made from g lass fibres (GF), carbon fibres (CF) and ara­ mid fibres (AF) . The latter two exhi bit very high tensile strengths but are seldom used owing to their high price. The quantity of non-woven fabrics, meshes, textiles and rovings i ncorporated l ies between 20 and 75% by mass. The combinations and the proportions of the individual components, the direction of the fibres, the elongation of the matrix at failure and the adhesion between fibres and matrix deter­ mine the properties of the composite material.

Fibre composites

Embedding fibres in synthetic materials im­ proves their mechan ical properties. Fi bre com­ posite systems consist of a base (matrix) of curing resins or thermoplastics plus a fibre material which is responsible for high strength, rigidity and thermal stability. The designations for fibre-reinforced plastics (FRP) are given in the order fibre-matrix, e . g . glass fibre-reinforced polyester resin (GF-UP) . The thermosetting materials suitable for use as a matrix are unsaturated polyester resins (UP) , epoxy resins (EP) and cross-linked polyurethanes (PUR) in the form of casting resins. Among the thermoplastics, polypropylene (PP) is just one of those that can be used for fibre composites. The building components with load bearing functions (e.g. structural sections, roofli ghts,

Synthetic materials made from regenerative raw materials

Owing to the enormous quantities of non­ degradable waste generated, our finite fossil resources and the high carbon d ioxide concen­ trations in the atmosphere, attempts are being made to produce synthetic materials from

Styrene-butadiene rubber (SBR) - elastomer

Owing to its extremely high wearing resistance, rubbery elastic behaviour and resistance to chemicals, SBR is ideal for floor coverings, waterproofing sheeting, seals and cable sheathing.

enc

0 "13 0) en 0> c

Silicones (SI)

Silicones possess simi lar features to plastics. However, instead of carbon atoms, inorganiC silicon atoms are responsible for forming the molecules. Owing to their chemical structure, silicones are designated as polysiloxanes (sili­ con-oxygen chains) , which exhi bit organic substituents (alkyl, vinyl and pheny l ) . On a commercial scale they are produced exclusive­ ly through polyreactions (e. g . step polymerisa­ tion) of low-molecular, sil icon organic com­ pounds. Depending on the length of the mole­ cule, this creates oily, resin- or rubber-type substances with outstanding resistance to high and low temperatures. The hydrophobic (water-repellent) behaviour of the silicone products and their consistent elas­ ticity during temperature fluctuations is exploit­ ed in sealing tapes and joint sealants made from siloxane elastomer (formerly silicone rub­ ber). Silicone resins are processed to form coatings and impregnations. I n addition , elastic

Applications of synthetic materials according to consumption

.� 0) .0

-0'" 0

--'

en() .� '"

Ci. -0 0)

E'"

0

LL

en

0) .0 .2

06 en0)

0.

0::

Polyethylene (PE)

·

Polypropylene (PP)

·

Polyvinyl chloride (PVC)

.

· .

Polystyrene (PS)

!!!.

0)

c '" 0.

06 en -0 ro0

(l)

o> E .� :;: 0 06 e o> o. c �", �0) 5 -55

en0) en

L 'c ""


>: 06 00 u::

o> m .f; en c 5 :9. :g0) m Cl)

•

U) �

0

Polycarbonate (PC)

.

·

c

�0

0


> 0) L -0
0 ·

0 .1

.1

0

·

Epoxy resins (EP)

·

Styrene-butadiene rubber (SBR)

·

0

Chloroprene rubber (CR)

·

0

Ethylene-propylene-diene rubber (EPDM)

·

0 0

Silicone (SI) 0 moderate consumption

.S:

en0)

'(ij

·

Polytetrafluoroethylene (PTFE)

• high consumption

en0>

0 .

Polyester resins (UP)

:J

0 0. E 0 () 0>

0

Polymethyl methacrylate (PM MA)

Polyurethane (PUR)

-0cen


. Iow consumption

0

.

1 reinforced with glass fibre

8 9. 1 3

95

Synthetic materials

B 9.14 B 9 . 1 4 Bonded glass, prototype o f a frame-less, self­ supporting glass shell made from 44 elements, Stuttgart, Germany, 2004, Lucio Blandini, Werner Sobek B 9 . 1 5 a-d Biodegradable plastic B 9 . 1 6 Physical parameters of selected synthetic materials B 9. 1 7 a-b Self-supporting elements made from glass fibre-reinforced plastic insulated with poly­ urethane foam, Futuro House, Finland, 1 968, Matti Suuronen

regenerative raw materials. G lucose is ob­ tained from p lants rich in starch such as maize, cereals, sugar beets or potatoes. A fermentation process turns the g lucose i nto lactic acid and a step polymerisation reaction in the next stage generates polymers from the lactic acid, e . g . polyactide (PLA) o r polyhydroxybuterate (PHB) . Mixed with additives, the properties of these "organic" plastics can be varied enormously: tough, viscous, biologically degradable or long-lasting. The properties and applications of transparent PLA are very simi lar to convention­ al thermoplastic materials such as polystyrene (PS) , polypropylene (PP) or polyethylene (PE ) . So far i t has been used for foodstuffs packag­ i n g , for films and pots in agriculture, and for coatings to paper and cardboard composites. The ongoing development of such synthetic materials will undoubtedly lead to a significant increase in the number of applications.

Applications for synthetic materials

The manufacturers of plastic products exploit not unlike a modu lar system - the specific pro­ perties of a synthetic material, the forming methods and the machining options i n order to produce a tailor-made material for a correspond­ ing range of applications. The same product is often available made from d ifferent synthetic materials. Users can then choose the best value for their money. This is reflected in the applications relevant to building (fi g . B 9. 1 3) : Load bearing components: shells, sections I nternal fitting-out, furniture: floor coverings, wall finishes, partitions Building envelope: facade elements, rooflights, ribbon windows, roof waterproofin g , membranes Building services: drinking water and waste water pipes Adhesives Binders for organ ic and inorganic substanc­ es, coatings Thermal and sound insulation Building preservation Solar collectors B 9. 1 5

96

Adhesives

According to D I N 1 6 920 adhesives are non­ metallic substances that join together work­ pieces by means of surface adhesion and internal cohesion. If two surfaces were to be produced perfectly flat and even - atomically perfect -, then the mutual attraction forces of the individual mole­ cules would be adequate to bond both surfac­ es together. Adhesives simu late this principle. They create the contact between two not per­ fectly flat and even surfaces with the help of the aforementioned attraction forces. In the case of smooth workpieces it i s necessary to roughen the surfaces mechanically or chemically in order to increase the surface area to which the molecules can bond. Basically, as the thick­ ness of adhesive increases, so the elasticity of the bonded joint i ncreases and its strength decreases. The material properties of the materials to be bonded demand the use of an appropriate adhesive. Porous materials such as wood, paper or textiles absorb the adhesive, which can lead to flaws in the joint but results in faster curi n g . Dense materials generally require adhesives with reactive curing processes that normally create a bond with a higher adhesive strength. As a rule, we d istinguish adhesives accord ing to their uses, e . g . according to form (liquid, sol i d ) , applications (wood, plastics, g lass, metals) or the processing temperature. Types of adhesive

Although almost all materials can be g lued together, there is a complex relationshi p between type o f adhesive, joint geometry, materials to be joined and loading. The manu­ facturers can supply suitably designed adhe­ sives that unfold their adhesive effect through the following curing mechanisms: without a chemical reaction the solvent evaporates or the adhesive cools to become solid; with a chemi­ cal reaction low-molecular constituents in the adhesive form high-molecular adhesive sub­ stances after applying the adhesive to the mating faces.

Synthetic materials

Synthetic material

Density

Tensile strength Modulus of elasticity

[kg/m3]

[N/mm']

[N/mm2]

Elongation at tear

Thermal conductivity

Thermal expansion

[%]

[W/mK]

[mm/mK]

Service & maximum temperature

re]

Thermoplastics Polyethylene

PE PE-LD

91 0-930

8-23

200-500

300-1 000

0.32

200-250

75/90

PE-HD

940-960

1 8-35

700-1 400

1 00-1 000

0.4

1 50-1 80

80/1 1 0

900-91 0

2 1 -37

1 1 00-1300

20- 800

0.22

1 1 0-1 70

1 00/ 1 40

1 70-400

0.15

1 50-2 1 0

55/65

1 0-50

0.16

70-80

Polypropylene

pp

Polyvinyl chloride

PVC PVC-P

1 1 60-1350

20-25

25-1 600

PVC-U

1 380-1550

50-75

1 000-3500

Polystyrene

PS

1 050

45-65

3200

3-4

0.16

70

70/80

Polymethyl metacrylate (Perspex)

PMMA

1 1 70-1 200

50-77

2700-3200

2-10

0.18

70-80

90/ 1 00

Polycarbonate

PC

1 200

56-67

2 1 00-2400

1 00-130

0. 1 8

60-70

1 35 / 1 60

Polytetrafluoroethylene (Teflon)

PTFE

2 1 50-2200

25-36

410

350-550

0.23

1 00-200

1 50/200

Polyurethane

PUR

1 050

70-80

4000

3-6

0.58

1 0-20

1 00 / 1 30

85/ 1 00

Thermosets Epoxy resins

EP

1 300

40-80

4000

2-1 0

0.23

Polyester resins

UP

1 200

35-75

4000

1-6

0.6

1 40

75

80/130 to 200 80/ 1 20

Glass fibre-reinforced polyester resins; glass fleece (GF) 30% by mass

1 400

90

7000

,; 1

n.a.

50

n.a.

polyester resins; glass cloth 40% by mass

1 500

1 30

9000

n.a.

70

n.a.

polyester resins; glass cloth 60% by mass

1 700

320

1 9 000

,; 1 ,; 1

n.a.

110

n.a.

Elastomers Styrene-butadiene rubber

S8R

Chloroprene rubber (Neoprene)

CR

Ethylene-propylene-diene rubber

EPDM

900-1 200

5-30

300-800

n.a.

n.a.

to 1 00

5-25

400-900

n.a.

n.a.

1 00 / 1 20

930-980

7-20

300-600

n.a.

n.a.

1 20 / 1 50

1 250-1900

4-1 0

1 00-500

0.3-0.4

20-50

1 80/230

1 420

Silicones Silicone

SI

8 9. 1 6

Hot-melt adhesives In a hot-melt adhesive the layer of adhesive cools or cures after being applied. Adhesives made from polyvinyl acetate (PVAC) or poly­ isobutylene (PI B) cool physically, epoxy resins (EP), melamine resins (MF) and phenolic resins (PF) cure chemically. Glues Water-based, organic glue solutions, e . g . on a PVAC basis, and g lues on a protein or carbo­ hydrate basis, cure physically through the evaporation of the water. Dispersion adhesives Acrylates or copolymers such as polyvinyl ace­ tate (PVAC) are finely dispersed in water and form a homogeneous film of adhesive after the dispersion medium has evaporated. Solvent adhesives These consist of organic solvents which partly dissolve the adhesive and also the workpieces and hence enhance the bon d . Solvent bond i n g with solvents uses dissolved synthetic surface coatings as an inherent adhesive, e . g . for roof­ ing felt.

Contact adhesives Contact adhesives are spread over the surfac­ es to be bonded. After both layers of adhesive have dried , the adhesive effect depends on the strength of the once-only contact pressure. The film of adhesive based on polyisobutylene (PI B) or chloroprene rubber (CR) remains rubbery elastic. Reaction resin adhesives The reaction resin adhesives can be d ivided into three groups;

Step polymerisation resins based on formal­ dehyde cure under the action of pressure and heat. One-part adhesives contain one component that triggers a chemical reaction only at high temperature. Two-part adhesives, e . g . based on poly­ urethane or epoxy resins, basically consist of a reaction resin that must be mixed with a hardener before using. The hardener pro­ duces the cross-linking.

b

8 9. 1 7

97

Life cycle assessments

"The question of efficient use of existing resour­ ces p lays a key role in the area of sustainable construction . Whereas numerous measures for reducing the heating energy requirements of buildings have already found their way i nto everyday design and planning activities, this i s not yet t h e case with respect t o the potential offered by an intelligent choice of materials. Alongside the aesthetic, functional and eco­ nomic criteria, the ecological effects of materi­ als and designs are i gnored or underestimated when making decisions. The reason for this can be found in the complexity of the subject and the resulting lack of information. However, as the critical crossroads for the environmental impact of a structure is reached at an early stage of the planning, information about the sustainability aspects of a building material or a design is required in a form that is readily usa­ ble and practical. As numerous pi lot projects have verified, the sustainable solution also makes sense i n economic terms. The total life cycle, i . e . the provision of the structure, its operation including renovation cycles and repairs right up to demolition and disposal, is relevant for the resulting materials flows. However, the design team often lacks the facts and hence the basis for making a realistic appraisal. Life cycle assessment is a tool that can be used to provide the data for comparisons. And life cycle assessment also g ives manufacturers guidance on how they can improve their products . " [ 1 ]

What is a life cycle assessment?

A life cycle assessment (LCA) is a crad le-to­ grave analysis of a building element. To do this we consider the stages in the l ife of the element such as acquiring the raw materials, produc­ tion, processing and transport, if necessary also consumption, reuse and disposal. Accord­ ing to ISO standards 1 4 040 to 1 4 043, the assessment is d ivided into three sections: inventory analysis, impact assessment and interpretation. Inventory analysis This i dentifies which materials and energy con­ version processes are relevant to the product. The boundaries for the assessment - the so­ called cut-off criteria - are usually set at m i n . 1 % mass o f material a n d primary energy con­ sumption. In the case of materials that have an i mpact on the environment (e. g . plasticisers in synthetic materials) , the cut-off criteria may need to be checked in some cases and possi­ bly overridden.

References [ 1 ) " I ntegration vergleichender Nachhaitigkeitskenn­ werte von Baumaterialien und Bauteilschichten", Sabine Djahanschah, DBU

98

Impact assessment This assesses the emissions of all materials and energy conversion stages. If manufactur­ er's data is not available, information on com­ parable processes must be obtained from databases. If specific information is replaced by comparable data, this must be noted by the

assessors. Every life cycle assessment there­ fore contains an appraisal of the basic data from which the load ing effect can be derived. The assessment requires the various emissions to be grouped according to their environmental effects (e. g . contribution to global warming) . There are no standardised specifications regarding the parameters to be presented. Therefore, the categories relevant for the envi­ ronmental impact of the product must be defined in individual cases. Interpretation The interpretation is based on the results of the impact assessment. According to ISO 1 4 043, the i nterpretation can be broken down into three steps: identifying the significant issues, evaluation, and presentation of the results. Non-assessed but nevertheless relevant data (e.g. durability, or emission of gases during the period of use) must be shown separately. The results should lead to conclusions and enable recommendations for the use of the product. Developments in life cycle assessment

Some European countries have already issued standards to enable an assessment in one uni­ fied parameter. However, the weighting of the parameters is subjective and cannot be scien­ tifically verified. In Germany the Federal Envi­ ronmental Agency has devised a method for c lassifying and ranking the i mpact categories. The assessment considers the extent of the impact (global - local; permanent - temporary), the current environmental condition in the area of the i mpact category (threatening - harmless) and the contribution of the impact category to the overall loading in Germany (major - minor) . The l ife cycle assessments g iven in this book are arranged according to these categories (from left to right) . In future the parameters required for the bui ld­ ing assessment will be provided by the manu­ facturers in the form of their standardised Envi­ ronmental Product Declarations (EPD) . They will have to be checked by independent third­ parties. In order that a uniform foundation for assessments is available in the meantime, the manufacturers of building products have agreed to set up a database for a transitional period. The parameters of a life cycle assessment

At the "Round Table on Sustainable Construc­ tion", which is coordinated by the Federal Min­ istry for Transport, Building and Housing, the participants agreed to use the indicators explained below. Primary energy input PEI [MJ} The primary energy input (embodied energy) of a building material describes the quantity of energy media (resources) required for the pro­ duction and use of the material. In doing so, we distinguish between renewable and non-renew­ able primary energy. 1 00 MJ corresponds to the calorific value of 2 . 8 I heating oil.

Life cycle assessments

Global warming potential GWP 1 00 [kg CO2-equivalent] The greenhouse effect causes i nfrared radia­ tion radiated from the Earth's surface to be reflected and, to a certain extent, rad iated back to the Earth. The accumu lation of greenhouse gases in the troposphere leads to increased reflection and hence an overall heating of the planet. The g lobal warming potential groups together gases in relation to the impact of car­ bon dioxide (COJ As the retention time of gases in the atmosphere is taken into account in the calculation, the time horizon considered (normal ly 1 00 years) must be stated . 1 0 kg CO2 emissions correspond approximately to the refining and incineration of 3 1 heating oil.

Durability [a] Durability describes the period in which a b u i l d i ng material can maintain its function in the use allocated to it. It is not compulsory (e.g. depend i n g on operations ) . A time range is usu­ ally stated according to the diverse influences affecting usage. The lower value describes the d urab i l ity for a conventional usage, the higher value relates to optimised planni n g . Calorific value [MJ] The calorific value describes the energy released during thermal recycl i n g (combustion) of a materia l . Energy bound by latent storage media in the air is not considered. 1 m3 wood has a calorific value of 80001 3 000 MJ ( 225-365 1 heating oil ) . =

Ozone depletion potential ODP [kg CClf-equivalent) Ozone is formed in the stratosphere when oxy­ gen (02) is exposed to ultraviolet l i g ht. The ozone absorbs some of the UV radiation and so only a fraction penetrates as far as the Earth's surface. The ozone depletion potential groups together the impact of various ozone-depleting gases. The reference variable used is CFC 1 1 (trichlorofluoromethane CCll) . Acidification potential AP [kg S02-equivalent] Acidification is mainly due to the conversion of airborne pollutants i nto acids. This results i n the pH value of precipitation been lowered . The acidification potential groups together all the substances contributi ng to acidification in rela­ tion to the impact of sulphur d ioxide (S02) ' Visible, secondary effects of acidification on buildings are, for example, the corrosion of metals and the decomposition of natural stone.

Recycling potential The recycl i ng potential describes the ecologi­ cal value of the "accumulation" of a material in the "technosphere". It shows how many envi­ ronmental loads can be spared in relation to the new provision of the material. A maximum collection quota of 95% is assumed. As the recycling potential represents a saving in the production, it consists of a complete data record with several parameters. If the complete recycling potential were to be used, the values for production would have to be lowered by the values for the recycl i ng potential. Recycling potential i n this book is given for metals only because these are currently the only building materials for which there i s a recycl i n g system in place with a h i g h degree of reuse.

The use of LeA data

Eutrophication potential EP [kg PO/-equivalent] Excessive fertil isation ( eutrophication) is understood to be the concentration of nutrients. In excessively ferti lised waters this can lead to fish kills and even "overturni n g " , i . e . to the bio­ logical death of the waters. Plants in excessive­ ly fertilised soils exhi bit a weakening of their tis­ sue and a lower resistance to environmental influences. Furthermore, a high nutrient input leads to a concentration of nitrate in groundwa­ ter and drinking water, where it can react to become nitrite, which is toxic for humans. The eutroph ication potential groups together the substances in comparison to the impact of phosphate (PO/ ) . =

Photochemical oxident creation potential POCP [kg Cfl4-equivalent] Nitrogen oxide and hydrocarbons produce aggressive reaction products, in particular ozone, when exposed to solar radiation. Photo­ chemical ozone formation (so-called summer smog) is suspected of causing damage to vegetation and materials. H i g her concentra­ tions of ozone are toxic to humans. The ozone formation potential is related to the i mpact of ethylene (C2H.) ,

From the designer's point of view, it is i n itially the comparison of building materials in the con­ text of the construction project that is interest­ ing in order to estimate the contribution of a building material to the build i n g 's overall load on the environment. Materials-related parame­ ters for a wide range of common building mate­ rials are l isted on pp. 1 00-1 0 1 . They are relat­ ed to either 1 m3 or 1 kg of the respective mate­ rial depending on a typical manufacturer's dec­ laration. They therefore enable an assessment of products in terms of general environmental issues, but cannot be d i rectly compared with each other due to the d ifferent reference varia­ bles and building performance characteristics. Considering the life cycle I n order to assess a building material over its entire life cycle, the recycl i n g options for the material and its durability must stil l be taken into account. As not every material can be allo­ cated a specific usage, it is only the applica­ tion-related approach in Part C that provides parameters for durabi l ity. A simple example is a plank of larch wood, which can be used as a floorboard for up to 50 years, but in facade cladding up to 70 years.

Calorific values (wood and synthetic materials) or recycling potential (metals) for the end of l ife (EOL) of a building material are specified in Part B. Those building materials without EOL values have a recycl i n g potential that is low in comparison to the production input (concrete, for example, can be recycled as an aggregate for new concrete, but the main input sti ll lies in the production of cement) . Furthermore, the "viabi l ity" of the recycl i n g must be assessed, i .e . the possibil ity of being able to collect sort­ ed building materials for recycling in the first place. In this respect, special attention must be paid to composite materials. For instance, considered over the entire l ife cycle of a b u i l d i n g , a floor covering with low durability (short replacement intervals) may result in h igher environmental loads than the loadbearing construction. Comparing LCAs Particularly interesting for architects and engi­ neers is p robably the comparison of forms of construction that are essentially identical in terms of building performance. But such "equivalent" designs may result in total ly differ­ ent ecological assessments. Contrary to "gen­ eral" opin ion, the use of environmentally friend­ ly alternatives need not mean having to make compromises in terms of functionality, aesthet­ ics or economic efficiency. Quite the opposite in fact: this form of assessment may intensify the planning process in some circumstances and encourage additional creativity. Examples of the functional comparison of materials appli­ cations can be found in Part C. Some data is presented in graphic form to ease the compari­ sons between i ndividual form of construction. The especially important parameters for non­ renewable primary energy input and global warming potential are highlighted by the length of the bar and the shadi n g , negative potential that can be assessed as generally positive indi­ cated by a lack of shadi n g , values < 1 x 1 0-8 are equated to zero in the tables. The parame­ ters are compared for every area of application and given a percentage, with the highest value in the environment category of an area of appli­ cation defined as 1 00%. Comparisons of con­ structions for d ifferent areas of appl ication are therefore only possible by using the parame­ ters. Producing your own comparisons To produce your own comparisons between different designs, is first necessary to deter­ mine suitable layers of materials with equivalent functions. In order to ensure that the state­ ments are not falsified, this process should take account of the entire l ife cycle, i .e. i ncluding durability and recycl i n g options. I n addition, the input requ i red to maintain the building compo­ nent should be i ncluded wherever possi ble. Fig. B 1 0 . 1 shows, as an example, a compari­ son between a soli d reinforced concrete floor and an edge-nailed timber floor with compara­ ble durabi l ity.

99

Life cycle assessments

Ref. unit

Material, material specification

Calorific value [MJ]

PEI primary energy non-renew.. renew. [MJ] [MJ]

GWP global warming [kg C02eq]

ODP ozone depletion [kg R 1 1 eq]

AP acidification

EP POCP eutrophication summer smog

[kg S02 eq]

[kg PO,eq]

[kg C2H,eq]

Solid reinforced concrete floor

Precast concrete element. 2% steel

(FE 360 B.

C 35/40). 1 20 mm

Recycling potential (FE 360 B. 85% primary)

Total: Edge-nailed timber floor

Pine, 1 2% moisture content (local), 1 80 mm Structural steel, hot-rolled section

(FE

360 B)

Total:

1 m2

492

10

-1 78

-4.2

55 -1 1

0.0000038

1 5 kg

1m

314

6.2

44

1 10

1 71 2

59

1 .4

1 68

1713

2

1 m2

1 580

2 . 5 kg

1 m

2

1 580

0.1 1 5

0.01 49

0.0145

-0.046

-0.0036

-0.0074

0.0000040

0.069

0.01 1 4

0.0070

- 1 43

0.00000 1 6

0.067

0.0074

0.0565

4.1

0.0000002

0.D13

0.00 1 1

0.0020

- 1 38

0.0000018

0.080

0.0085

0.0585

2.5 E{17

B 1 0. 1

lated on the basis of a theoretical means of pro­ duction between 1 990 and 1 999 at the Bauhaus University in Weimar ( I REB) and the University of Karlsruhe (ifi b ) , and are based on acknowl­ edged sources such as the Ecoinvent Data­ base (Swiss Federal I nstitute of Technology) . The underlying data is not always equivalent. Reasons for this i nclude the d ifferent strategies with which processes are considered and the way the fundamental data is determined. One example that illustrates the d ifferent approach­ es is gypsum. Whereas LEGEP assesses natu­ ral gypsum, GaBi - in accordance with the per­ centages consumed in Germany - considers 50% natural gypsum and 50% desulpho gyp­ sum (a by-product of flue gas desulpherisation in coal-fired power stations) . I n order to guarantee consistency withi n the programs, no data was transferred between them . Deviations between the i ndividual pro­ grams are denoted by in order to show that further coord ination work is required at this

The recycling potential of FE 360 B i s added to the reinforced concrete floor because after the period of usage the structural steel can be recycled. On the other hand, the reuse of the metal nails in the edge-nailed timber element appears unlikely and is therefore not consid­ ered. The comparison reveals better values for the edge-nailed timber element virtually throughout. Its stored primary energy (calorific value) is released again upon combustion to produce electricity and heat.

Origin of the data

Two computer programs were used for the assessments in this book. The program used for Part B (GaBi 4) made use of data based on experience from cooperation with industry plus patents and trade literature. In contrast to this, the software for Part C (LEGEP) provides assessments using inventory analyses calcu-

B 1 0. 1 Compilation of application-related life cycle assessment values using the example of an inter­ mediate floor

*

Ref. unit

Material, material specification data origin (see above)

point. The best matches between the l ife cycle assessments of the programs can be found in the parameters non-renewable primary energy input and g lobal warming potential. The goal of comparabil ity among l ife cycle assessment data has therefore not yet been completely realised.

Calorific value [MJ]

PEI primary energy non-renew. renew. [MJ] [MJ]

GWP global warming [kg C02eq]

B 1 0.2 Material-related life cycle assessment values for

ODP ozone depletion [kg R 1 1 eq]

common building materials

AP acidification

EP POCP eutrophication summer smog

[kg S02eq]

[kg PO,eq]

[kg C2H,eq]

Stone

p = 2750 kg/m' p = 2500 kg/m'

Granite' (India), polished,

1 m'

9837

332

626

0.0001 2

4.5

0.45

0.35

Sandstone (local), sawn,

1 m'

4099

1 53

253

0.000047

0.48

0.076

0.058

1 m'

4608

1 65

286

0.000055

0.64

0. 1 0

0.084

m'

6749

249

422

0.000080

1 .8

0.20

0. 1 6

9.7

0 .000003

0.068

0.D1 1

0.D1 1

74

0 .000003

0. 1 2

0.D1 1

0.01 6

0.037

Slates' (local),

p=

2700 kg/m'

Marble (Italy). polished,

p=

1

2700 kg/m'

Loam Compacted loam',

p=

2200 kg/m'

Loam bricks (sun-dried)',

p

=

1 200 kg/m'

1 m'

1 58

1 m'

1 257

4

Materials with mineral binders Mortars and screeds Anhydrite, comp. strength class 20, 2350 kg/m'

1 m'

655

11

43

0.0000 1 0

0.24

0.040

Magnesia ', comp. strength class 20, 2000 kg/m'

1 m'

2439

9.9

348

0.00001 6

0.44

0.060

0.070

Cement, comp. strength class 20, 2250 kg/m'

1 m'

2161

27

389

0.000020

0.85

0. 1 3

0.099

Gypsum, class (for render) P IV a ,

1 m'

1 477

9.6

1 77

0.000008

0. 1 5

0.D 1 6

0.029

1 m'

2675

28

448

0.000020

0.61

0.090

0.083

Calcium silicate,

1 m'

2030

117

247

0.000008

0.22

0.031

0.035

Concrete (paving).

1 m'

1 990

46

310

0.0000 1 3

0.55

0.080

0.056

1 m'

1 484

81

1 86

0.0000 1 0

0.29

0.051

0.040

1 m'

787

35

97

0.00001 1

0.33

0.048

0.048

2340 kg/m'

1 m'

1 549

17

251

0.0000 1 8

0.68

0.1 1

0.086

2360 kg/m'

1 m'

1 764

23

320

0.00001 6

0.68

0. 1 0

0.078

1 m'

4098

86

455

0.000031

0.96

0.12

0. 1 2

1 m'

26839

116

2200

0.00020

4.3

0.60

1 .04

1 m'

2655

251

1 50

0.000027

0.41

0.063

0.052

p=

Lime-cement, class (for render) P l l a,

1 300 kg/m'

p=

1 500 kg/m'

Masonry units

p = 1 800 kg/m' p = 2500 kg/m' Aerated concrete, p = 400 kg/m' Lightweight concrete', p = 600 kg/m' Concrete In situ concrete (C 25/30), P In situ concrete (C 35/45). P

=

=

Precast concrete element, 2% steel (FE360B, C 35/45), Boards Cement fibreboard' ,

p=

2500 kg/m'

p=

1 750 kg/m'

Gypsum plasterboard' (type A) .

1 00

p=

850 kg/m'

Life cycle assessments

Ref. unit

Material, material specification

Calorific value [MJ]

PEI primary energy non-renew.. renew. [MJ] [MJ]

GWP global warming [kg C02 eq]

ODP ozone depletion [kg R 1 1 eq]

AP acidification

POCP EP eutrophication summer smog

[kg S02eq]

[kg PO.eq]

Ceramic materials

p=

1 m3

1 485

638

95

0.0000 1 0

0.31

0.034

0.050

1 m3

1 663

715

1 07

0.00001 1

0.34

0.038

0.056

1 m3

4776

39

301

0.000029

0.79

0.084

0.14

Glazed stoneware',

1 m3

6322

0.060

393

8.50

0.96

0.067

0.084

Unglazed

1 m3

7 1 60

0 .070

445

8.50

1 .00

0 . 069

0.093

Pure straighl-run bitumen' (B 1 OO-B 70)

1 kg

45.6

0.01 0

0.37

0.000001 0

0.0020

0.00028

0.0026

Polymer-modified bitumen (PmB 65A)

1 kg

35.3

0.020

0.50

8.24

0.00 1 8

0.00023

0.00 1 9

Vert. perforated clay bricks, external wal l , Clay bricks, internal wall, p = 750 kg/m3 Solid engineering bricks (KMz),

p=

670 kg/m3

1 600 kg/m3

p = 2000 kg/m3 stoneware, p = 2000 kg/m3

E-07 E-07

Bituminous materials

E 07

Wood and wood-based products Sawn timber Pine, 1 2% MC' (local), ODD 450 kg/m3

1 m3

8775

609

951 2

-792 '

0 .000009

0.37

0.041

0.31

Western red cedar, 1 2% MC (N. Am.), ODD" 630 kg/m3

1 m3

1 2285

4485

1 4359

-907 '

0 .000049

6.00

0.61

0.56

Teak, 1 2% MC (Brazil), ODD 660 kg/m3

1 m3

1 2870

32 1 7

1 3435

-1013 '

0.0000 1 5

3.99

0.41

0.37

Glued laminated timber, 1 2% MC, ODD 465 kg/m3

1 m3

9300

3578

1 3870

-662 '

0 .000053

1 .57

0. 1 9

1 .0

3-ply core plywood , 1 2% MC, ODD 430 kg/m3

1 m3

861 8

261 7

-648 '

0 .000030

0.54

0.065

0.36

Veneer plywood (BFU), 5% MC, ODD 490 kg/m3

1 m3

1 0 1 75

4729

9387 1 5041

-636 '

0.000070

1 .62

0.19

1 .3

Particle board (P5, V1 00), 8.5% MC, ODD 690 kg/m3

1 m3

1 3998

581 8

1 26 1 4

-821 '

0 .000086

1 .22

0. 1 6

0.40

Oriented slrand bd. (OSB), 4% MC, ODD 620 kg/m3

1 m3

1 2555

4593

1 6479

-839 '

0. 000052

1 .52

0. 1 9

1 .3

Med. density librebd. (MDFr, 7.5% MC, ODD 725 kg/m3

1 m3

1 5843

9767

1 2495

-51 5 '

0 .000066

1 .48

0.28

1 .4

Wood·based products

Metals Ferrous metals Cast iron', casting (GG20; secondary), GJL

1 kg

10

0.49

0.97

0.000 1 1

0.000 1 8

1 kg

24

0.54

1 .7

4.26 E·08 6.62 E·08

0 . 00 1 3

Structural steel, hot-rolled section (FE360B)

0 . 0051

0.00042

0.00082

Steel mesh as concrete reinforcement (secondary)

1 kg

13

0.24

0.83

9.40 E·08

0 . 0020

0.000 1 6

0.00031

Weathering steel , cold-rolled strip

1 kg

26

0.56

2.0

8.30 E·08

0.0057

0.00046

0.00088

1 kg

54

6.3

4.8

4.41 E·o7

0 . 037

0.0 1 2

0.0026 0.01 0

(Wf St 37-2),

2 mm

Stainless steel (V2A, X 5 CrNi 1 8- 1 0) , 2 mm Non-ferrous metals Alum. alloy (EN AW-7022 [AIZn5Mg3CuJ ) , sheet, 2 mm

1 kg

271

38

22

0. 000004

0.069

0.0057

Lead', sheet, 2 mm

1 kg

34

1 .9

2.3

2.88 E·07

0.041

0.00061

0.0025

Titanium-zinc (pure Zn Z1 , 0.003% T i ) , sheet, 2 mm

1 kg

45

3.8

2.6

5.59 E·o7

0.01 8

0.001 0

0.00 1 3

Copper', sheet, 2 mm

1 kg

37

4.6

2.5

1 .84 E·07

0.01 8

0.0023

0.0021

Steel (FE 360 B, 85 % primary)

1 kg

-12

-0.28

-0.71

1 .65 E·08

-0.00024

-0.00050

1 kg

-13

-0.25

-0.77

1 .60

-0.0034

-0.00025

-0.00053

Stainless steel (CrNi 1 8-1 0, 25 % primary)

1 kg

-13

- 1 .2

-0.99

E·08 -4.30 E-08

-0.0031

Steel

-0.021

-0.0071

-0.00 1 2

Aluminium (EN AW-7022 , 1 00 % primary)

1 kg

- 1 77

-34

-1 6

-0.000003

-0.053

-0.0041

-0.0081

Lead

1 kg

-2 1

- 1 .3

-1 .5

- 1 .68

-0.036

-0.00043

-0.0021

Titanium zinc (65 % primary)

1 kg

-29

-2.9

-1 . 7

-3.86

-0.0 1 4

-0.00075

-0.00097

Copper (50 % primary)

1 kg

-18

-4.5

-1 .4

-9.97

-0.0 1 5

-0.0021

-0.00 1 8

14

0.08

0.88

2.83 E·08

0.006408

0 .00090

Metal, recycling potential

(Wf St 37 -2,

85 % primary)

E·07 E-07 E-08

Glass Float glass',

p=

1 kg

2500 kg/m3

0.00053

Synthetic materials Thermoplastics Polyethylene (PE-HD)', film

1 kg

0.09

1 .82

0.000001

0.0050

0.00063

0.0059

1 kg

41 17

75

Polyvinyl chloride (PVC- Pl', compound f. waterproof sht.

61

2.1

2.28

8.97

0.0 1 3

0.001 2

0.0021

Polyvinyl chloride (PVC-

1 kg

14

52

0.59

2.05

7.02

0.0072

0.00066

0.001 7

Polymethyl methacrylate (PMMA "Perspex"), , panel

1 kg

24

87

0.29

3.39

0.000001

0.01 0

0.00 1 0

0.0031

Polytetrafluoroethylene (PTFE "Tetlon"), coating

1 kg

8.3

295

2.5

1 6.2

0 .000008

0.069

0.0042

0.0068

EPDM', sealing gasket

1 kg

27

76

0.25

1 .97

5.60

0.0082

0.00054

0.0029

Polyester resin' (UP)

1 kg

32

115

0.45

4.68

0.000002

0.01 2

0.00 1 7

0.0059

Epoxy resin (EP)

1 kg

app. 30

1 37

0.78

6.47

0 .000002

0.01 4

0.0021

0.0050

Styrene-butadiene rubber (SBR), sealing gasket

1 kg

37

1 02

0.85

3.05

9.68

0.01 0

0.00096

0.0040

Chloroprene rubber (CR "Neopren"), bearing

1 kg

app. 25

96

0.96

3.65

8.81

0.01 2

0.00 1 0

0.0031

Silicone (SI), sealing compound

1 kg

app. 25

91

30

4.07

7.43

0.028

0.00 1 7

0.0023

Hr,

compound for pipes

E-07 E·07 E-07

Thermosets

Elastomers

E·o7 E-07 E·07

Transport HGV'/22 t perm. tot. load/1 4 . 5 t payload/local/85% u s e

1 /t km

Sea-going vessel', contain. ship/approx. 27 500 dwt/at sea 1 1t km

1 .5

0.00031

0.1 1

3.87 E·08

0.00099

0.0001 6

0.000 1 9

0. 1 7

0.00004

0.0 1 3

4.34 E{)9

0.00045

0.000041

0.000033

, The negative global warming potential of wood is due to the carbon dioxide that is removed from the atmosphere during photosynthesis. This is then released again upon rotting or burning of the wood at the end of its useful life. MC Moisture content ; ODD oven dry density

B 1 0.2

1 01

Part C Applications of building materials

The building envelope 2

Insulating and sealing

3

Building services

4

Wal l s

5

I ntermediate floors

6

Floors

7

Surfaces and coatings

Fig. C Timber-and-glass facade employing structural sealant glazing, Mont Cenis Training Academy, Herne, Germany, 1 999, Jourda & Perraudin, Hegger Hegger Schleiff

1 03

The building envelope

C 1 .1

"The house of the North is a climate castle in whose thick wal l s rather small windows have been cut. That fosters the acknowledgment of a d ivided world: the c l imate outside, the domes­ tic oven, the human warmth inside. In terms of insulation this is a successful answer, but this is probably the only successful aspect. Was it a good idea to divide the world into alien and familiar, into object and subject, into i nside and outside?" Otl Aicher I n historical terms the need for protection against a hostile outside world and extreme weather conditions provides us with the prima­ ry reason for any building activity - the creation of an effective barrier against the external envi­ ronment. And as mankin d 's technology pro­ gressed, so the demands placed on the build­ ing envelope m u ltiplied (fig . C 1 .6) . As the threshold between inside and outside belonging to both the building and the urban space - the building envelope takes on a spe­ c ial sig nificance. To the outside world the facade is the building's calling card as it were, the owners presenting their conception of themselves to the public. In this context, the facade makes an impression on the urban landscape. Added to the primary protective functions are other requirements necessary for satisfying the occupants' demands for comfort ( e . g . protection against glare and excessive heat) . At the same time, the quality of the external walls and roofs have a crucial influence on the energy audit of the b uild ing.

Facade - skin and clothing

The facade - derived from the Latin word facies is traditionally the "face" of a b u i l d i n g . I n earli­ er times the facade designated the princi pal side of a building only, the side presented to the public, the side containing the entrance. Observers perceived each building as a part of a street front, and were unaware of its three­ dimensional configuration (fig . C 1 .4 ) . D uring the Modern Movement t h e term "facade" was deleted from the architect's vocabulary because of its traditional associa-

C 1 .1 C C C C C

"Cow Project", Vogelsberg, Hesse, Germany, 1 986, Formalhaut 1 .2 Systematic classification of functional criteria 1 .3 Systematic classification of constructional criteria 1 .4 San Giorgio Maggiore Church, Venice, Italy, 1 566, Andrea Palladio 1 .5 Cowshed, Garkau Estate near LObeck, Germany, 1 925, Hugo Haring 1 .6 The requirements and tasks of building envelopes (left: outside)

1 04

tions. Modernism was very fond of free-stand­ ing structures that required special treatment to their surfaces on all sides. Their external appearance had to harmonise with their func­ tions and internal utilisation (fig . C 1.5). The "skin and skeleton" terminology interprets the connection between internal arrangement and external configuration as an inseparable whole. Releasi n g the p lane of the facade from its load­ bearing functions enabled the external skin to be completely detached from the structure of the building and it became the curtain wal l . The outcome of this was the worldwide popularity of glass-fronted office blocks with flat curtain walls during the 1 960s and 1 970s. Contemporary building design is more con­ cerned with the conceptual and textural quali­ ties of surfaces and their desired effects, and less concerned with pragmatic or ideological issues relating to the "honest" use of the mate­ rials. The perceivable surface of the enclosing "envelope" detached from the structure of the building becomes the focus of our attention. Today, the treatment of the building envelope can be based on any one of a number of differ­ ent approaches. Besides the rediscovery of tra­ ditional building materials such as stone, tim­ ber and clay brickwork, the surface character­ istics are being increasingly influenced by industrial products such as plastic sheets, ply­ wood and weathering steel (fig. C 1 .9) . New manufacturing techniques for adding coatings to glass and the printing options for d ifferent surfaces promote the rebirth of orna­ mentation and decoration. The materials of the building envelope are receding into the back­ ground to the benefit of the images that need to be conveyed (fig . C 1 .8) . The topics of sustainable construction provide us with another approach: the building enve­ lope is designed as a multi-layer skin that reacts to internal and external conditions plus constantly chan g i n g requirements (fi g . C 1 . 1 0) . This means that various functional layers regu­ late the protection against excessive heat and glare, redirect the light and provide the build­ ing with energy.

The building envelope

Permeability - air

Permeability - light

Energy gains

Variability

Control

I

closed partly permeable open

Part of structure

Make-up in layers

opaque translucent semi-transparent transparent

Make-up in leaves

I

none heat electricitv

Ventilated air cavity

not variable mechanical physical - structure chemical - substance

Prefabrication

low high

manually, direcVindirect "self-regulating" with control technology C 1.3

C 1 .2

Principles

Knowledge about the specific external condi­ tions, the internal utilisation requirements p lus the interaction of the individual aspects forms the foundation for the design of a building envelope. Furthermore, a whole range of gen­ eral criteria apply to facade design irrespective of the choice of material. Functional criteria

The change in our awareness of the use of fos­ sil fuels has led in recent years to the contem­ porary climate concept of the building enve­ lope becoming the focal point of the desig n , first and foremost t o exploit the passive options of the facade as an i nterface between inside and outside (fig . C 1 .2 ) . The building services provide the remaining energy requirements and cover peak loads. Until well into the 1 970s it was fashionable to reduce users' options for regulating and influencing "their" facades (especially in office buildings) . But following the rapid developments in the control of building services in recent years there are now more and more attempts to provide, on the one hand, "self-regulati ng" systems ( e . g . thermo­ tropic glazing) plus, on the other, " Iow-tech" solutions with manual operation (e.g. hinged or sliding shutters) . Furthermore, the building envelope is being used more and more as an active energy provider. I n this respect, the i nte­ gration of solar technology into the building

envelope ( e . g . photovoltaic modules and solar col lectors) provides numerous design options in addition to the roof-mounted, add-on sys­ tems frequently encountered.

---f ----------------- ---------+------------

--

Heat storage Energy gains

Constructional criteria

Constructional criteria have a crucial effect on the design of facades (fi g . C 1 .3) . The decision as to whether the external wal l should be load­ bearing or not is always linked with other design issues. Loadbearing elements such as wal l s and columns can dominate and configure the b u i l d i n g through the regularity of the struc­ tural requirements. Another fundamental decision is whether to use a sing le- or mUlti-layer assembly. Whereas in traditional masonry and solid timber (log) con­ struction all the requirements placed on the envelope are satisfied by a single, monolithic layer, modern external wal l designs usually consist of several coordinated layers that fulfi l the respective tasks ( e . g . loadbearing, insulat­ ing, waterproofing) in a certain order. "Layers" can be, for example, p laster, render or thermal insulation composite systems that themselves cannot carry any loads or form part of a hig her­ order construction (fig . C 1 .7) .

Thermal insulation

Protection from wind

---+--------- ----------

Natural lighting Controlled permeability of diffuse daylight

---f --. ---

Controlled permeability Direct sunlight (sunshade, glare protection)

--

--------- ----------

View through, visual link

Natural ventilation

--- -

Protection against precipitation

Regulation of humidity, vapour diffusion

Protecting wall against saturation

----1f--------- ------------------- ---------+------.

Sound insulation

Protection against mechanical damage

----

-----

Fire protection

Protection against intruders C 1 .4

C 1 .5

C 1 .6 105

The building envelope

I I

C 1 .7

C C C C

External wall designs (left: outside) a one leaf, one layer b one leaf, multiple layers c multiple leaves, one layer d multiple leaves, multiple layers inside 1 .8 University library, Cottbus, Germany, 2004, Herzog & de Meuron 1 .9 Casa Jax, Tucson, Arizona, USA, 2002, Rick Joy 1 . 1 0 Office building, Stuttgart, Germany, 1 998, Behnisch, Behnisch & Partner 1 . 1 1 Systematic classification of external wall claddings

11 a

Building performance criteria

In order to g uarantee the durabi lity and serv­ iceabil ity of external wall designs, the b u i l d ing performance properties of the individ ual layers must be carefully coordinated with each other. It should also be remembered that the thermal and sound insulation, fire protection and mois­ ture control provisions influence each other and can be optimised only when considering all the aspects together. Thermal insulation Good thermal insulation in the external compo­ nents ensures not only the comfort of the occu­ pants but also helps to reduce the heating and/ or cooling requirements - and hence the run­ ning costs - quite significantly. It also protects the fabric of the building against damage caused by climatic influences (e.g. thermal stresses, moisture, frost) . The thermal conduc­ tivity of the external wal l construction essential­ ly depends on: •

• •

the thermal conductivities of the ind ividual component layers and primary b u i l d i n g mate­ rials the thicknesses of the building material layers the moisture contents of the building materials

Moisture control Better thermal insulation i n the external compo­ nents also helps to reduce the risk of conden­ sation forming, but in winter there is an increased

C 1 .8

1 06

I

• c

b

risk in the case of cavity and internal i nsulation. Condensation can have an effect on the interior climate (mould growth) and the durability of the external wal l construction. In order to avoid condensation in temperate c l imates, the fol l ow­ ing principles should be applied: Vary the vapour-tightness of the materials from more vapour-tight on the inside to more vapour-permeable on the outside. I ncrease the minimum building component temperature by placing thermal insulation on the outside.

II

d

C17

air cavity increase the degree of sound atten­ uation. . The sound i nsulation characteristics of the windows make a major contribution to the overall sound insulation index of the building envelope.

·

·

Sound insulation Facades of sound insu lation classes 1 -6 to VDI D i rective 2719 are provided according to the prevai l i n g external noise level . The minimum value for the airborne sound insulation index l ies between 30 and 50 dB depending on the respective utilisation. If the external noise level exceeds 75 dB, enhanced requirements must be satisfied . The following principles should be taken into account for sound insulation: ·

·

•

•

Heavyweight walls can i nsulate agai nst noise; the airborne sound insulation of components increases with their wei g ht per unit area. Homogeneous external walls attenuate the sound better than inhomogeneous ones. The airborne sound insulation can be improved by using additional, separated, elastically supported leaves and wider air cavities Porous materials positioned adjacent to the

C 1 .9

Fire protection I n the event of a fire, the b u i l d in g envelope must prevent or delay the spread of the fire, guarantee the load bearing capacity of the con­ struction for a defined period of time and hence help to protect the lives of the bui l di ng's occu­ pants. Choice of building material and type of construction depend on the fire protection requirements and the protective measures required for components at risk based on the building code of the respective federal state plus numerous other directives (TUV, D I N , VDE, etc . ) . A l l materials used in buildings must be classified according to the D I N 4 1 02 or D I N EN 1 3501 building materials classes (see "Glossary", p. 264 ) .

The building envelope

brick slips

All enclosing components must be permanently protected against the effects of the weather, especially against driving rai n . Fig. C 1 . 1 1 shows a selection of potential external wal l claddings corresponding to the classification into single- and mUlti-layer opaque external wall designs.

Small-format natural stone panels Single-leaf, multi-layer designs render

Render/plaster

thermal insulation render

Thermal insulation composite system

Besides layers of plaster and render and ther­ mal insulation composite systems (see "Sur­ faces and coatings", p. 191 ) , small-format natu­ ral and reconstituted stone un its plus ceramic materials (all bedded in mortar) can be used as the external cladding to single-leaf envelopes. When planning single-leaf constructions, owing to the different material properties of facings and backings, special attention must be paid to thermal stresses, swelling and shrinkage proc­ esses and the formation of condensation. As the surface temperatures of dark cladding materials can fluctuate - depend i n g on the season - between -20 and +85°C, the associat­ ed movements of and stresses in the compo­ nents should be consi dered and allowed for i n the details.

rl

� facing leaf I cast wall I gabion wall

·

•

The insulating materials (see " I nsulating and sealing", p. 132) must cover the external wal l completely without any gaps a n d b e attached with mechanical fasteners. Penetrations through the insulating layer and into the sup­ porting construction form thermal bridges and should be avoided wherever possible. The ventilated air cavity must be at least 20 mm wide, the size of the ventilation open­ ings at the top and bottom of the cavity must have an area equal to min. 50 cm2 per metre of wall length. Supporting frameworks are usually of timber or aluminium. Such frameworks must be able to move and twist in all directions in order to avoid restraint stresses.

I I

Stone

I

H

�

Materials with mineral binders

y rl I L

Glass

I

in situ concrete

I

fibre-cement slates

I

I

I precast concrete

I I gran ulated slag aggr· 1

f-

I concrete units I � reconstituted stone I

I

engineering bricks ceramic panels

I

asphalt shingles

I

hollow glass blocks

I

� Cast glass

profiled glass

I

�_Sheet glass

-l float glass I I body-tinted glass I f- I acid-etched glass I I sand-blasted glass I I Y enamelled glass

: Pressed glass

Multi-leaf, single- and m Ulti-layer designs

I

suspended stone panels

I I

:

Bituminous materials

I

� calcium silicate units

� Unreinforced

Ceramic materials

I

I composite panels � slates Ij Reinforced

Multi-leaf, single- and multi-layer designs

·

stoneware tiles

Small-format reconsti­ tuted stone panels

Claddings bedded in mortar

Single-leaf, multi-layer designs

Multi-leaf constructions with a ventilated cavity reduce the building performance risks when compared to claddings bedded in mortar. Also, as the building get older, it is still possible to renew the external weatherproof leaf with mini­ mum effort and without having to change the loadbearing and/or insulating layers. Besides their classification into material groups (timber, glass, metal, etc . ) , external wall clad­ dings can be classified according to the type of fixing, i.e. exposed (nails, rivets, bolts) or concealed (undercut anchors, suspended sys­ tems) . Concealed fixings are becomi n g more and more popular in order to achieve a better appearance. The following rules apply to designs with a ventilated cavity:

I split-face blocks

Ceramic materials

External wall claddings

J-

rl

I I I I I

with welted seams and batten rolls

I profiled sheets

�

Metal

I

I

I

I panels I trays Y cast plates

Timber

�

rl 3-ply core plywood

I I facade-gr. plywood I I lamin. veneer l umber I

Y y

i

I I

shakeS/shingles

Y Wood-based productsf-

Synthetic materials

I

sawn timber

,j Solid timber

H

shingles

,

wood-cement partiCle board flat, m ulti-walled and corrugated sheets

I membranes moulded parts

I I

I C 1.11

1 07

The building envelope

a

b

e

c

d

g

h C 1 .1 3

C 1 .1 2

Solid timber and wood-based products

External wal l claddings have always been adapted to the typical regional weather condi­ tions and characteristics using the building materials available locally. Timber cladding has proved worthwhile for many centuries, particu­ larly in Germany's heavily forested, mountain­ ous regions. However, owin g to the numerous design options timber is now being favoured in many other locations (fig . C 1 . 1 7) . Wood-based products complement the application and design options of the (usually) small-format solid timber facades and have been used throughout Europe for the past 20 years. Planned and installed properly, timber cladding can last for well over 1 00 years (fig . C 1 . 1 2) . Whereas in earlier generations a timber exter­ nal leaf always implied a timber load bearing construction underneath, today the choice of cladding is no longer l inked with the primary load bearing construction.

ber facades must be taken into account at the Fast drain i n g of precipitation without ponding through the use of rainwater drips (provide draft design phase. As a rule, the cladding sheet metal at window sills if necessary) and materials of low-rise bui ldings, i.e. those in by avoiding capillary joints. which the finished floor level (FFL) of the h i ghest Permanent protection to narrow surfaces and habitable room is < 7 m above the surrounding edges. ground level, must comply with building materi­ Preferably install the timber with the d i rection als class B2 (flammable), which applies to all of grain matching the drainage direction of the timber claddings given here. I n medium-rise the rainwater; planed surfaces dry quicker buildings (top FFL 7-22 m above ground level) than rough-sawn ones. building materials class B1 (not readily flamma­ Provide an effective ventilated cavity behind ble) is required, and only a few wood-based the external leaf. products achieve this classification (fig . C 1 . 1 4) . Use non-rusting fasteners to prevent i m pair­ Above 22 m the use of incombustible materials (building materials class A) is prescri bed . Only ing the appearance of the facade. a few wood-cement particleboards satisfy this External wall cladding of solid timber requirement. However, i n conjunction with spe­ cial fire protection concepts (e. g . sprinkler sys­ When selecting boards for the cladding, take tems, protected escape routes), exceptions to into account the timber's natural resistance to the rules can be applied for. The serviceability insects and fun g i . The wood must be selected and durabil ity of timber facades is d i rectly relat­ accordi n g to the requirements and the durabili­ ed to the design and construction principles: ty classes of DIN EN 350-2 (from 1 very dura­ ble, to 5 not durable) (see "Wood and wood­ based products", fig . B 6 . 1 1 , p. 70) . The boards Protection against driving rain achieved with appropriately sized overhang i n g eaves and are attached with the heartwood side on the outside to minimise the size of joints due to adequate protection against splashing water at the base of the wall (fig . C 1 . 1 6); it should subsequent swelling and shrinkage move­ ments. To allow movement and avoid fissures, be possible to replace any severely exposed the boards must be fixed free from all restraint. elements if necessary. ·

·

•

•

·

=

=

•

General planning advice

The numerous regulations of the respective building codes with regard to permissible mini­ mum distances to neighbouring buildings and the building materials classes required for tim-

C 1 . 1 2 Romeo and Juliet Windmill, Taliesin, Wisconsin, USA, 1 896, Frank Lloyd Wright C 1 . 1 3 Forms of cladding a vertical staggered planks b vertical planks with cover strips c vertical planks with concealed strips d vertical profiled boards e horizontal profiled boards f horizontal planks with open joints g weatherboarding h small-format shingles/shakes C 1 . 1 4 Wood-based boards for cladding external walls, with details of building materials class to D I N 4 1 02 C 1 . 1 5 Horizontal jointing options for wood-based boards a closed joint with Z-section "flashing" b concealed joint a

1 08

b

c

The building envelope

Wood-based board 3-ply core plywood facade-grade plywood laminated veneer lumber (LVL) wood-cement particleboard

Building materials class B2 B2 B2 B1 /A2 C 1 .14

C 1 .1 6 Options for protecting base of wall against splashing water a 300 mm clearance between ground and bottom edge of cladding b "sacrificial", replaceable plinth element C 1 . 1 7 External wall claddings of solid timber and wood­ based products a small-format standard shingles/shakes b decorative shingles/shakes c horizontal planking d weatherboarding e vertical planks with cover strips f narrow vertical planking g vertical planking with open joints h facade-grade plywood with clear lacquer finish i rough-sawn facade-grade plywood j cement-bonded particleboard with cover strips

b

a

Sawn timber and profiled boards From both the design and construction view­ point it is important to decide first between the various vertical and horizontal types of board­ ing (fig. C 1 . 1 3) . The advantage of vertical boarding is that rainwater drains quickly and depending on the height of the b u i l d i n g - it is possible to achieve a uniform board length without longitudinal joints. However, the hori­ zontal end grain surfaces, e . g . at eaves and openings, require very careful deta i l i n g . The overlap of weatherboard ing must be equal to min. 1 2% of the cover width of the board. Hori­ zontal boards with open joints are attached at an angle or the edges c ut with a splay so that water does not remain on the individual boards. On facades exposed to extreme weather con­ ditions there is an increased risk of moisture damage. Profiled boards with tong u e and groove joints can be attached with the joints either exposed or concealed. However, it should be remembered that if fixed with the joints engaged ( i . e. concealed ) , replacing the boards in the event of damage always i nvolves considerable work.

e

Wooden shakes and shingles Smal l-format shakes and shingles can be attached to facades in a double-lap tiling arrangement. Both tapered and parallel split shakes or sawn shingles can be used. Howev­ er, the surface of sawn shingles weathers con­ siderably faster because the wood fibres are severed during sawin g . Besides the rectangu­ lar standard shakes/shingles about 50-350 mm wide, various decorative shapes are also avail­ able. External wall cladding using wood-based products

Fig. C 1 . 1 4 l i sts wood-based products that are suitable for use as external wal l cladding and comply with the requirements of HWS class 1 00 (see "Wood and wood-based products", p. 72) . The board formats, the pattern of the joints and the surface characteristics - rough­ sawn, brushed, sand-blasted or sanded with abrasives - govern the appearance of the facade. Horizontal joints emphasise the storeys of the build i n g , but usually require suitable pro­ tection (fi g . C 1 . 1 5) . Alternatively, cover strips can provide this protection (fi g . C 1 . 1 7 j) . Con­ cealed fasteners are also avai lable in addition to more conventional, exposed screws.

g

h

n�

C 1 .1 6

C 1 .15 Surface finishes

A chemical timber preservative to DIN 68800-3 is not requ ired for solid timber external wall claddings with a ventilated cavity because the anticipated moisture content of the wood is insufficient for fungal growth. Among the wood­ based products, 3-ply core plywood and lami­ nated veneer lumber can remain untreated if required and then will assume a natural grey patina over time. The ultraviolet radiation breaks down the small lignin molecules (the "putty" substance in wood) into its water-solu­ ble constituents, which are then washed out over the years. The remaining white, fibrous cellulose forms a rel ief-like grainy pattern in the d i rection of the grain; the wood takes on its typ­ ical grey or silvery patina. For details of translu­ cent or opaque coloured coatings for timber surfaces, see "Surfaces and coating" (p. 1 97 ) .

C 1 .17

1 09

The building envelope

durability of such composite panels still has to be proven i n practice.

Stone

When using stone as an external wal l clad d i n g , make sure that the physical characteristics of the type of stone chosen (which vary enor­ mously, see "Stone", p. 43) comply with the weather conditions at the site:

Retaining fastener Sliding sleeve

· ·

•

•

thermal expansion deformations due to fluctuations in the mois­ ture content (swelling and shrinkage) resistance to frost and de-icing salts (espe­ cially at the base of the wal l ) chemical stabil ity (S0 a n d CO ) 2 2

Facing leaves

Facing leaves of natural stone are usually 90 mm thick. In comparison to suspended stone cladding panels, they are less vulnerable to damage at the base of the wal l caused by horizontal loads (e. g . vehicle impact, malicious damage). The load-carrying capacity via the masonry bond and the fixing of the outer leaf to the primary construction is achieved in a simi lar way to faci n g brickwork. Stone facing leaves enable the full spectrum of surface finishes to be employed (see "Stone", p. 42) .

Stone cladding panels C 1 .18

C 1 . 1 8 Supporting a n d retaining fasteners for stone cladding panels C 1 . 1 9 Facing unit formats and proportions of joints for wall claddings of small-format natural stone, reconstituted stone and ceramic materials bedded in mortar C 1 .20 External wall claddings of natural stone (selection) a suspended Eifel basalt cladding panels with ventilated air cavity b storey-height composite stone panels c facing leaf of sandstone d gab ion wall with cages filled with Altmuhltaler dolomite e cast wall f slips of Brazilian oil shale

These days, owing to the economic and build­ i n g performance advantages, stone facades are usually built as suspended (curtain wal l ) assemblies with a venti lated cavity. T h e fixing of the stone panels to the supporting construc­ tion is labour- and materials-intensive. All the fasteners (dowels, bolted/screwed fixi ngs, cramps and corbels) must be made from stain­ less steel to D I N 1 7 440 to avoid corrosion blemishes on the surface of the stone . Normal­ ly, every panel i s held by three or four fixings, and fixing without restraint must be guaranteed (fig . C 1 . 1 8) . The panel thickness depends on the type of stone (hard or soft) and the structur­ al calculations, and is normally 30-50 mm. Joints accommodate movements and help ven­ tilate the cavity behind; they are 8 - 1 0 mm wide depending on panel size. The use of open (drained) joints obviates the need for construc­ tion and expansion joints; however, they dimin­ ish the overall effect of the stone facade. As an alternative, joints can be filled with mortar, and movement joints sealed with s i l icone with a sanded finish. Nevertheless, ventilation behind the panels must sti l l be guarantee d . The otherwise comparatively favourable l ife cycle assessment of natural stone is spoi led by the large number of construction elements required. I n order to reduce the work on site, a number of manufacturers have developed stone composite panels consisting of a back­ ing of aluminium or expanded clay and a 6 mm stone "veneer". This makes them considerably lighter than sol id stone panels. However, the

a

c

I

Split-face blocks Slips

o

12

18

20

30

Proportion of joints [%)

1 10

33

36 C 1 .19

b

d

Gabion walls

Gabions are wire mesh cages filled with a graded assortment of loose stones - preferably material available locally (fig . C 1 .20 d ) . They have been used for centuries in civil engineer­ i n g and landscaping works, but their first use in a building was in 1 994 when lan Ritchie used them on his arts centre in Terrasson, France. Cast walls

Cast walls comprise stones (usually recycled) built up in courses and cast in concrete between formwork at the front and a compres­ sion-resistant insulating material at the back (fig . C 1 .2 0 e ) . The alternating courses of stone and concrete results in a charmi n g appear­ ance. Small-format stone tiles bedded in mortar

Tiles with an area < 0 . 1 m2 and a thickness � 30 mm can be bedded d i rectly in mortar spread over a suitable substrate. To allow for unevenness, the mortar bed is min. 1 0 mm thick, but 20 mm is better. The thermal and moisture-related movements of such a clad­ d i n g , which is firmly attached to the substrate, must be accommodated by 1 0 mm expansion joints at a spacing of max. 6 m . It is not usually the intention of such cladding to imitate load­ beari ng masonry. Therefore, the tiles are attached with regular, 4-6 mm wide X-joints, but sometimes small formats are used in a masonry bond (fi g . C 1 . 1 9) .

e

C 1 .20

The building envelope

a

Clay bricks and ceramic materials

Like hardly any other building material, the design and construction of masonry requ i res great discipline and knowledge of the details appropriate to this material. "We can also learn from brick, How sensible is this small handy shape, so useful for every pur­ pose! What logic in its bonding, pattern and texture! What richness in the simplest wal l sur­ face! But what d iscipline this material i mposes!" Ludwig Mies van der Rohe Double-leaf facing masonry

D I N 1 053 makes a fundamental distinction between double-leaf masonry with and without an air cavity, The minimum thickness of the fac­ ing leaf should be 90 mm in order to g uarantee stability, but is usually 1 1 5 mm, Only water­ repellent, frost-resistant clay faci n g or hard­ burned (engineering) bricks, preferably sol id types, free from efflorescence can be consid­ ered for such applications, Small-format masonry units in thin format ( D F) measuring 240 x 1 1 5 x 52 mm or standard format ( N F) measuring 240 x 1 1 5 x 7 1 mm are normally used for external leaves, The use of medium­ format masonry units (2-DF format etc,) leads to an imbalance between joints and units and an aesthetically unsatisfying result. Double-leaf masonry with air cavity and thermal insulation The maximum permissible d i stance between inner and outer leaves is 1 50 mm, The air cavi­ ty should not be less than 40 mm wide, So if we exploit the maximum distance, then that leaves only 1 1 0 mm for the thermal insulation, Ade­ quately sized ventilation openings (7500 mm2 per 20 m2 of facade) , which can be provided in

d

c

b

the form of open perpends or air-bricks, are required at the top and bottom of the wall in order to guarantee the necessary circulation of air (those at the bottom can also be used for drainag e ) , However, the large wall thickness of about 500 mm (assuming a 240 mm load bear­ ing leaf) means that this very durable form of wall construction req uires more work on site, and also noticeably reduces the amount of usa­ ble interior space, Double-leaf masonry with cavity insulation If we abandon the air cavity and completely fi l l the space between the leaves with thermal i nsu­ lating material, this totally changes the building performance boundary conditions, Only water­ repellent insulating materials are suitable for this form of construction , Careful construction of the outer leaf is required in order to prevent ingress of water throughout the l ife of the bui lding, Faci n g leaves requ ire vertical expansion joints at a spacing of 5 - 1 2 m depending on the orien­ tation or incident solar radiation, plus the colour and surface finish of the masonry units, Horizon­ tal movement joints are not required in buildings up to 12 m high, On taller buildings the external leaf must be supported on brackets and move­ ment joints included beneath such brackets, Like all double-leaf masonry walls, D I N 1 053-1 stipulates 3 - 7 wal l ties per square metre (dependi n g on tie d iameter, spacing of leaves and height of external wal l above ground level ) , Besides t h e colour a n d surface characteristics of the masonry units plus the size and colour of the joints, it is primarily the choice of the mason­ ry bond that affects the character of a facade, Stretcher bond with a half-brick overlap can quickly become monotonous when used on large areas, When using older, more decorative bonds, half-bricks must be used as the "bind­ ers" (fig, C 1 ,2 1 ) ,

C 1 ,21

Brick slips, split-face blocks and ceramic wall tiles bedded in mortar

For advice on these ceramic external wall clad­ dings, please refer to the information on small­ format stone tiles bedded in mortar (p, 1 1 0) , Suspended ceramic panels with ventilated cavity

Extruded ceramic panels with open (drained) joints have only recently become available for use as a curtain wall-type, ventilated rainproof clad d i n g , Compared to double-leaf masonry, fired ceramic panels have construction and building performance advantages owin g to their low weight. They normally consist of two profiled panels (with rebate top and bottom plus rainwater drip) factory-joined by webs to form a twin-walled profile, Such panels are approx, 1 50-250 mm high x approx, 300450 mm wide for a panel thickness of 30 mm, The fired ceramic panels are usually supplied i n their natural colour, vitrified panels are not widely used at the moment. The supporting construction normally consists of aluminium members, but occasionally tim­ ber, and has the task of transferrin g the weight of the panels, wind forces and thermal fluctua­ tions to the load bearing structure without restraint. To drain run-off water, the horizontal joints are either overlapped l ike scales, or the panels are g iven a rainwater drip, A baffle in the vertical joints protects agai nst driving rain and also p revents the panels from rattling in the wind,

C 1,21 Decorative masonry bonds a Dutch bond b Flemish bond c Monk bond d Silesian bond C 1 ,22 Ceramic external wall claddings a recycled clay bricks b glazed bricks c grooved ceramic panels d stoneware tiles a

b

c

111

The building envelope

Mineral building materials

The range of facade applications for m i neral building materials extends from monolithic in situ concrete to small-format faci n g masonry units to the relatively lig htweight, suspended, fibre-cement sheets. Fair-face concrete

Architects appreciate the monolithic effect of fair-face concrete facades - load bearing struc­ ture, facade, floor coverings and external works in just one building material for a u niform appearance. But contrasting with the apparent simplicity are the often complex behind-the­ scenes toi l and painstaking workmanship. For example, on the art gallery in Lichtenstein it took five months to grind and polish the in situ concrete facade until the desired mirror-like finish was achieved (fig . C 1 .27d ) . Thermal insulation a n d other building perform­ ance requirements usually make it necessary to construct a double-leaf fair-face concrete facade. Thermal bridges at junctions, openings and penetrations cannot be avoided comp l ete­ ly and can be m i nimised only through careful , detailed plan n i n g . We essentially d istinguish between in situ and precast concrete facades; both can be b u i lt with a wide range of surface finishes (fi g . C 1.23) .

g

h

C 1 .23

C 1 .23 Concrete surface finishes a smooth formwork, grey cement b rough-sawn, unplaned boards, grey cement c acid-washed, coloured aggregate with rounded grains, grey cement d lightly brushed and unwashed, Rhine sand and porphyry aggregate, 0-16 mm, white cement, 1 % iron oxide red e pitched, limestone aggregate, grey cement f reconstituted stone panel, ground, l ight and dark aggregate, white cement g blasted, Singenhofer quartzite aggregate, 0-1 6 mm, white cement, 0.2% iron oxide yellow h transparent glaze, mineral paint C 1 .24 Minimum clearances for fixing fibre-cement sheets to timber framework C 1 .25 Fixing system with cast-in channels for cladding panels C 1 .26 Fixing system with supporting fasteners for connecting the layers of sandwich elements C 1 .27 Concrete facades a smooth formwork b rough-sawn boards c concrete mix with gravel containing soil, sur­ face finished with coarse pointing after striking formwork d concrete mix with of green and black basalt aggregates, surface ground and polished e printed precast concrete elements f precast concrete elements g "textile block" system, 400 x 400 m m h concrete blocks made with white cement i small-format fibre-cement slates in double-lap arrangement j large-format fibre-cement sheets with red coating

In situ concrete Besides the concrete mix (fi g . C 1 .27 c ) , it i s primarily the choice o f formwork or formwork system that governs the appearance of a fair­ face concrete facade. Absorbent formwork, e . g . rough-sawn boards (fig . C 1 .27 b ) , leaves behind a rou g h texture but by drawing air out of the surface of the concrete reduces the number of pores and cavities. Non-absorbent formwork (fi g . C 1 .27 a) renders possi ble the creation of (almost) smooth surfaces; however, such formwork encourages the formation of pores, blemishes and discoloration. A wall thickness of � 1 75 mm has proved to be the minimum for proper placing and compacting of the concrete in facing leaves. For further advice on in situ concrete walls, please refer to "Walls" (p. 1 53) and " Building materials with m i neral binders" (p. 58) .

a

112

b

Precast concrete elements The factory production, unaffected by the vagaries of the weather, enables precast con­ crete elements to be produced with better quality and precision (fi g . C 1 .27 f) . The hori­ zontal compaction on vi brating tables results in elements with low porosity. Additional surface finishes (e. g . flame treatment, acid-etching) are also available, and silk-screen printing and the use of a retarder in the mix enable patterns and motifs to be applied to the surfaces of precast concrete panels (fig . C 1 .27) . However, transport and erection place limits on the dimensions and weight of precast concrete elements. They should not exceed 1 5 m2 and a length of 5 m. To ensure that changes in length due to temperature and humidity fluctuations are safely accommodated, approx. 1 mm width of expansion joint should be provided per metre of precast concrete (see " I nsulating and sealing", p. 1 40). We distinguish between sandwich elements and single- or dual-layer cladding panels with a rubble stone or similar fac i n g . Storey-height wall panels normally require two interlocking or screwed fixings arranged symmetrically (fi g . C 1 .25). Sandwich elements consist of three or four lay­ ers (fac i n g , air cavity if required, insulation and loadbearing) and can be used for loadbearing, bracing or non-load bearing functions. The fac­ i n g layer must be at least 70 mm thick in order to guarantee the concrete cover required ( l i ke with curtain wall panels) , but this can be reduced by using textiles or other thin reinforc­ ing layers. The layers are bonded together with support anchors (vertical forces ) , retaining anchors (horizontal forces) and ties (wind forc­ es) (fi g . C 1 .26) . Facing masonry of concrete

Calcium silicate faci n g masonry units as well as cement-bonded granulated slag aggregate units (see " Building materials with mineral bind­ ers", p . 60) exhibit similar properties and can also be employed for facing leaves. D I N 1 8 1 53 specifies the technical, material and geometri­ cal requirements. The standard distinguishes between the following:

c

d

The building envelope

•

•

u

facing bricks (Vm) masonry units without voids facing blocks (Vmb) masonry units with voids =

=

Facing bricks and blocks are produced in both the octametric ( 1 /8 M 1 25 mm) and the met­ ric ( 1 / 1 0 M 1 00 mm) d imensional coordina­ tion systems. Wall thicknesses of 90, 1 00, 1 1 5, 140 and 1 90 mm are possi ble, also 240 mm for facing blocks. The exact designation of concrete faci n g masonry units is made up o f t h e type of unit, DIN number, strength class, density class and dimensions, e.g. facing unit DIN 1 8153 Vm28 - 2.2 - OF. Frank Lloyd Wright had experimented with his decorated "textile block" system (fig. C 1 .27 g) as early as the 1 920s. The range of surface qualities obtainable is enormous and extends from open-pore, closed-pore, lightly brushed and washed, and sand-blasted to rough-split. Individual colour requirements can be achieved by adding inorganic p i gments in the form of natural stone particles ( e . g . granite, porphyry and basalt) . The planning advice (spacing of leaves, wall ties, brackets, etc. see p . 1 1 1 ) for clay brickwork also applies to double-leaf con­ crete facing masonry. Movement joints � 1 5 mm wide should be included every 6-1 0 m in order to minimise cracking (fi g . C 1 .27 h ) .

o

=

1>30mm

=

Reconstituted stone panels

Plain ( unreinforced) reconstituted stone pan­ els are produced in sizes of 0.2-1 .0 m2 and a minimum thickness of (usual ly) 40 mm from concrete of grade C 55/67. The shape and col­ our of the aggregates (principally marble and limestone granulate) can be enhanced by sur­ face treatments such as sand-blasting, grind­ ing and polishing (fig. C 1 .23f). The planning information given for cladding panels of natural stone also apply to the dimensions and fixing of reconstituted stone panels according to D I N 1 8 5 1 6 (see p. 1 1 0) . =

Fibre-cement slates and sheets

The first patent for fibre-cement slates was granted in 1 901 . In those days they were pro-

Water­ stop

I

C 1 .24

duced primarily from cement with the addition of approx. 1 0% asbestos fibres and water. Asbestos (the Greek word for indestructible) i s a generic term for a group o f natural, fibrous, m i neral silicate compounds. However, when these very fine and long-lastin g fibres get into the lungs, they can cause cell damage, a d isor­ der known as asbestosis (see "Glossary", p . 268) . Owing to the enormous health risks associated with asbestos, the industry has been produci n g non-asbestos products since the 1 980s (see "Building materials with mineral binders", p . 61 ) ; an E U ban on asbestos came into force in 2005. Generally, we d istinguish between the small­ format slate and the large-format sheet, both of which can be produced in l ight grey and white (using Portland and white cement respectively), or in various colours, or with a g laze, or with an opaque coloured coating.

n

C 1 .25

C 1 .26

with hooks to match the colour of the slate. Loadbearing frameworks of aluminium also make use of riveted fixings. Large-format fibre-cement sheets Large-format sheets are available in sizes up to 3 1 00 x 1 250 mm and thicknesses of (usually) 8-1 2 mm. They are generally erected flush and attached to the supportin g construction by means of screws, rivets or concealed undercut anchors. Owin g to the high coefficient of ther­ mal expansion in the case of aluminium sup­ porting constructions, expansion joints in the supporting construction must guarantee that the fibre-cement sheets are fixed without any restraint. The joint width between sheets is about 1 0 mm (fi g . C 1 .24). Horizontal joints are usually of the open (drained) variety, but verti­ cal joints are provided with a waterstop. Large­ format corrugated sheets can also be used, attached vertically or horizontally.

Small-format fibre-cement slates Building authority approval is not required for slates up to 0.4 m2 and max. 5 kg . These smal l­ format materials (e.g. 200 x 300 or 400 x 400 mm) are hung on the facade in overlapping arrange­ ments accordi n g to trade recommendations, e . g . double-lap, d iagonal, etc. (fig . C 1 .27 i ) . The supporting construction for such slates generally comprises horizontal tiling battens mounted on vertical counter battens. Fibre­ cement slates are fixed with special rustproof nails of copper of galvanised steel, alternatively

I

e

Fixing screw

h

I

C 1 .27

1 13

The building envelope

L b

v

HN

c

External wal l clad d i n g s of metal are very long­ lasting and require little maintenance. Although the metals themselves are relatively heavy, the material thicknesses used (normally � 1 mm depend i ng on the metal) mean that this is always a l i g htweight form of construction, which has benefits for the design of the load­ bearing structure. The methods of shapi n g and i nstallation are wel l establ ished and range from manual folding to large-format trays with a high degree of prefabrication. Whereas the metal curtain wal l s of the 1 950s were often associated with the attributes "tech­ nical" or "cold", these days we value their pre­ cise surface q ualities plus their specific l i g ht and colour effects. Various metals can be used for the facade, e . g . aluminium, lead, stainless steel, copper, steel, weathering steel or zinc (for properties see "Meta l " , fig. B 7. 1 0, p. 80, and fi g . B 7. 1 7, p. 83).

I

HN

a

Metal

d

sen or additional measures (e. g . shaping, stiff­ ening members on the back, folded edges) must be employed in order to guarantee the necessary rigid ity. Fixings can be exposed (penetrating the material) or concealed (no penetration) . Different types of installation, sys­ tems and semi-finished products are used for metal claddings: •

General planning advice

HN

HN

e C 1 .28

C 1 .28 Types of installation, systems and semi-finished products (selection) H = horizontal section, V = vertical section a open (drained) ioint b standing seam c profiled metal sheets d shingles e panels f trays C 1 .29 Metal facades (selection) a colour-coated horizontal panels, 250 x 1 600 mm b sheet lead with standing seams c titanium shingles d weatherin9 steel e 35 mm wide copper strips "woven" between vertical larch wood battens f cast aluminium panels with imprinted pattern

a

114

b

External wall claddings of metal are practically vapour-tight. In order to avoid the formation of condensation, the ventilation openings must equal :2! 1 / 1 000 (inlets) and :2! 1 / 800 (outlets) of the wal l area. A vapour barrier should be i ncluded on the inside adjacent to areas with high water vapour concentrations. The wind suction forces and temperature-relat­ ed changes in length are the main factors determining the material d i mensions and type of i nstallation. Temperature differences in the exterior climate lead to increases in length between 1 .2 mm/m (steel) and 2.2 mm/m (tita­ nium-zinc) . The use of sliding fixings and ade­ quately sized joints guarantees that the clad­ ding is fixed to the supporting construction without any restraint. Protection against corrosion plays a major role in terms of the stabil ity of the facade and should therefore be considered at an early stage (see "Metal", p. 78) .

•

•

•

•

Processing and installation

Metal cladd ings must remain stable, and so depending on material and type of installation, an appropriate material thickness must be cho-

c

d

e

Sheet metal with welted/standing seams or batten rolls: Non-self-supporting sheet metal in approx. 600 mm wide bays is normally attached to rough-sawn tongue and g roove boarding, although systems comprising metal sections can be used to meet higher fire protection requirements. Double welt (standing) seams or batten rol l s are the traditional methods of construction (fig . C 1 .28 b) well known from roofi n g (see p. 1 24) . Even though the welted seams are these days mainly formed by machine, this is sti l l a manual installation technique which does not result in perfectly smooth surfaces (fig . C 1 .29 b ) . Shing les These small-format elements enable the structure to be covered in a net-like cladd ing. Their small size and good formability are ideal for covering rounded surfaces (figs C 1 .28 d and C 1 .29 c ) . They are fixed to boards or a grid of battens manually using clips or nails. Profiled sheets: A large selection of profiled metal sheets is available (fig . C 1 .30) . Profiled sheets can be attached to the facade horizontally or vertical­ ly and fixed to a timber or metal supporting framework (fig . C 1 .28 c ) . Panels: Panels are available with interlocking or over­ lapping seams, also as horizontal panels, and can be installed flush or overlapping in vari­ ous d i rections (figs C 1 .2 8 e and C 1 .29 a) . Fixing is usually by way of concealed rivets in the joints. Trays: The folds on all sides enable trays to be pro­ d uced with larger d imensions and in propor­ tions from 1 : 1 to approx. 1 :4, but are never­ theless very stable. They are usually fixed

C 1 .29

The building envelope

b

tion, and are not considered further in this sec­ tion. External wall constructions using mem­ branes in tension (films, textiles) are dealt with on p. 1 29.

c

walled sheets

a

External wall claddings of flat, corrugated and multi­

d

e

�

C 1 .31

C 1 .30

•

with the rivets or screws positioned in the joints (fig. C 1 .28f) , but systems with con­ cealed hooks are also available. Cast sheets: Cast sheets are highly resistant to mechanical damage and can be produced i n aluminium (also bronze if required) with any type of sur­ face finish (fig. C 1 .29f) . They are normally hung on concealed fixings.

Solid aluminium sheets, sandwich panels or weathering steel are among those types of metal cladding that can also be installed with open (drained) joints (fig . C 1 .28a). Large-for­ mat sheet metal can be shaped to fit rounded facade geometries. Furthermore, various semi­ finished products such as perforated and embossed sheets, expanded metal, louvres, metal strips, metal fabrics and meshes place a whole range of options at the architect's d is­ posal and render new facade designs possi ble (fig. C 1 .2g e).

Synthetic materials

Due to the incorrect choice and use of materi­ als plus technological deficiencies in the mate­ rials themselves, the willingness to experiment with the use of plastics as an architectural material in the 1 960s and 1 970s ran out of steam, at the latest by the time the oil crisis took hold in the mid-1 970s. But the use of plastics has been growing since the early 1 990s; Rem Koolhaas, for example, used g lass fi bre-reinforced plastic corrugated sheets as external wall cladding on his art gal­ lery in Rotterdam (fig . C 1 .32 a). Synthetic materials underwent a change of image - from cheap product to contemporary b u i l d i n g mate­ rial - and this resulted in considerably better qual ity products and a much wider range of products available on the market. External wall claddings usually make use of conventional semi-fin ished products such as flat, corrugated and mu lti-walled sheets. One of the primary material properties of p lastic - its ease of shaping - is absent from sheets, or is at best only limited. Moulded parts produced using casting or laminating techniques demand a high manual input, despite industrial produc-

In contrast to external wall claddings of g lass, transparent or translucent synthetic materials have the advantages of low wei g ht and a high load-carrying capacity at low cost. The synthet­ ic materials suitable for facades in the form of sheet-type semi-fin ished products are: PM MA, PC, and g l ass fibre-reinforced UP, PET and PVC. Fire protection requirements must be consid­ ered when choosing the material. Basically, PET and PVC satisfy the requirements of build­ ing materials class B 1 ; PMMA, PC, and glass fibre-reinforced plastics fal l into class B2. How­ ever, ind ividual products with special formula­ tions (e. g . the add ition of a flame-retardant) may deviate from the general classification; in such cases special approval is necessary. Acrylic sheet (e.g. Perspex) is permanently resistant to ultraviolet radiation and the effects of the weather, but all the other synthetic mate­ rials listed above generally carry a g uarantee of max. 1 0 years. The U-value of double-walled sheets (i.e. single row of voids) is 2,5 W/m2K, but such sheets are available with up to six wal l s ( i . e. five rows of voids) and the U-value of such sheets is 1 .2 W/m2K. Processing and fixing The seasonal changes in temperature which amount to > 50 K lead to changes in length of 3-5 mm/m depending on type of material and sheet thickness. Holes and fasteners must therefore be designed in such a way that fixing without restraint is guaranteed. Plastic sheets are fixed with conventional fasteners (fig. C 1 .3 1 ) . Corrugated sheets attached to walls are fixed through the troughs, and not through the crests as is the case for roof surfaces. Multi-walled sheets are normally installed with the voids ver­ tical in order to prevent condensation collecting.

C 1 .30 Profiled metal sheets a flat (E) b shallow ribs (L) c grooves (N) d micro-profile (M) e trapezoidal profile (T) f corrugated profile (W) C 1 .31 Methods of fixing various semi-finished products C 1 .32 External wall claddings using synthetic materials a corrugated sheets made from glass fibre­ reinforced plastic (GFRP), lit from behind b triple-walled polycarbonate panel, rear face co-extruded in different colour c transparent polycarbonate corrugated sheet revealing straw insulation behind d translucent polycarbonate double-walled panel with tongue and groove joints a

b

c

d

C 1 .32

1 15

The building envelope

a

b

Glass

loads for cleaning and maintenance must be allowed for on horizontal and sloping g lazin g ; dependi n g on thermal req u i rements, laminated safety g lass or a composite comprising lami­ nated safety g lass ( i nside) and toughened safety g lass is used. Laminated safety glass is also used for vertical safety barriers without any self-supportin g protective elements (handrail etc . ) . The corresponding technical regulations (e. g . TRAV) apply to vertical glazin g , the top edge of which is > 4 m above the adjoining level . Laminated safety glass can be used as single g lazin g , as the inner pane of an insulat­ ing glass unit, or as an outer pane with tough­ ened safety g lass on the inside. The load-carry­ i n g capacity can be verified either with calcula­ tions or by means of the pendulum impact test ( including the supporting construction) .

I n the architecture of the past few decades, the theme of transparency has played a dominant role, also as a signal for openness and commu­ nication. On the one hand, more slender and more l i ghtweight fixing systems, on the other, new glass technologies, have enabled archi­ tects to sound out the whole spectrum of possi­ bilities between transparent, translucent and opaque g lazing (fig . C 1 .33) , and at the same time have improved the thermal and optical properties. Besides the traditional frame, frame-less, sealed and overlapping forms of glazing have appeared. Furthermore, g lass facades with a ventilated cavity are becoming increasingly popular.

C 1 .33

Requirements

Glass facades have to satisfy numerous techni­ cal requirements. The incident solar radiation requires special attention. Exploited properly, solar radiation can contribute significantly to the energy requirements of a bu ildin g, and improve the comfort of occupants and q uality of the incoming l ight. On the other hand, solar radiation can lead to overheating, a poor interi­ or climate and to considerably higher energy and technical requirements and hence costs. For information on choosing the right type of g lass see "Glass" (pp. 86-89) . Safety Owing to the properties of glass, safety aspects may have to be considere d , depend­ ing on the particular application. The very spe­ cific way in which glass fai l s means that people must be protected against splinters of g lass falling from above, or prevented from falling through g lass barriers and spandrel panels. We distinguish here between overhead glazing (pitch > 1 0°) and vertical glazing . Only types of glass with sufficient residual load-carrying capacity may be used for overhead g lazin g . Supported along t h e edges, wired g lass can span up to 700 mm, laminated safety glass made from heat-treated glass up to 1 200 mm. Cut-outs in overhead glazing are not permitted. Other types of support and larger spans must be checked in each individual case. Additional

Areas of application

Glass facades have proved to be especially durable. I n terms of architecture, laminated and insulating glass - comprising various types of sheet g lass - enable many different types of surface finish (figs C 1 .36 c-f) . External wall cladding with ventilated cavity The facade cladd i n g products in widespread use include obscured g lass, body-tinted glass, glass with a coloured coatin g and patterned glass. Sandwich elements are also available, e.g. backing panels of expanded glass granu­ late with a coloured coating p lus toughened safety g lass on both sides. The requirements to be satisfied by a facade of toughened safety g lass with a ventilated cavity are stipulated in D I N 1 8 51 6-4. The structural analysis determines the thickness of the glass, but a nominal thickness of 6 mm is the mini­ mum permitted. All panes must undergo a heat-soak test prior to installation (see p. 87). A cladding comprising more than one pane requires a cavity at least 30 mm wide. Single-leaf glass facades Open or unheated interiors such as atria or conservatories require glass without a thermal break. As a free-standing wal l , such g lazing can also be used to satisfy sound i nsulation requirements. Heated interiors requ ire insulat-

C 1 .33 Pharmacology Research Centre, Biberach, Germany, 2002, Sauerbruch Hutton Architekten a vertical louvres open b vertical louvres closed C 1 .34 Fixings for glass a patent glazing bar with cap to clamp glass in place b individual clamp fixing c individual screw fixing through hole d structural sealant glazing (SSG) with mechani­ cal retainer C 1 .35 Systematic classification of glass facades C 1 .36 Glass facades with various types of glazing a cable net with overlapping panes b flush cable net c printed glass, individual fixings through drilled holes, loads transferred via spider brackets d glass printed with text, individual clamp fixings e printed glass, individual clamp fixings f double-leaf profiled glass facade

ing or heat-absorbing glass. The standard is double glazing with a system U-value (i.e. including the frame) of 1 . 1 - 1 .4 W/m2K. I n pas­ sive-energy housing triple glazing with a sys­ tem U-value of 0.7-0.8 W/m2K is normal. Build­ i n g s with high i nternal thermal loads or no external sunshadi n g can be protected against excessive solar gains (to a certain extent) by solar-control glass. G lass bricks and blocks achieve U-values as low as 1 .5 W/m2K, depending on type. They are installed with continuous mortar joints. Double-leaf glass facades Double-leaf g lass facades are used as part of a climatic building control system or for sound insulation purposes. In the case of sound insu­ lation, the inner leaf (insulating glass) provides the thermal break function, and the outer leaf is responsible for the sound insulation. Firstly, the pane of glass reflects part of the sound, and secondly, the cavity open to the outside cre­ ates oscillations that contribute - through inter­ ference - to the absorption of the sound waves (Helmholtz resonator). With an appropriate building height and a system of openings in the facade, such a system can also be used to provide protection from the wind. Translucent profiled glass, which can be built with (Jne or two leaves, represents a special form of external g lass wall (fig C 1 .36 f) . The glass channels are held on two sides by alu­ minium sections and bonded together with sili-

a

b

c

d C 1 .34

116

The building envelope

Glass facades

Rigid facade elements

clamped leaded light timber frame metal frame plastic frame profiled glass

clamping sections structural sealant glazing individual fixings

cone. Profiled glass is self-supporting up to two storeys. In a double-leaf arrangement, a U­ value of 2.0 W/m2K is possi ble, and with a fill­ ing of capillary-structure material this can be reduced to 1 .4 W/m2K. Forms of construction

The supporting structure has a decisive effect on the overall architectural impression of a glass facade. We d istinguish between com­ pression and tension systems. Systems in ten­ sion offer greater design freedom because the loads do not need to be carried at the bottom of the elements, but instead place increased demands on the structure.

Post-and-rail designs The most common form of construction is the post-and-rail facade. This consists of vertical primary members and horizontal secondary members - usually of aluminium, steel or tim­ ber. This form of construction enables all the loadbearing components to be sized accordi n g to the loads they have t o carry. The primary members can be loaded either in tension (sus­ pended) or in compression (supported). This form of construction requires the glass fix­ ings and seals or gaskets to be fitted on site, which calls for more generous tolerances. And as this type of design forces the panes of glass to be fitted from the outside, large, prefabricat­ ed facade elements are preferred in order to

screwed

side-hung vertical pivot

hopper top-hung horizontal pivot

push-out sliding

screwed bracket spider bracket

C 1 .35

offset the high cost of the scaffolding to a cer­ tain extent.

fore be ensured that all rainwater can drain away readily from all fixings and frames.

Framed designs I n contrast to the post-and-rail facade, the ele­ ments, mainly loaded in compression, are always mounted from the inside. Prefabrication results in better tolerances and better sealing . A continuous layer of insulation in the frame sections open to the outside can avoid thermal bridges.

Continuous support The panes of glass are held over their entire length by means of glazing beads or the wings/ caps of patent glazing bars. For instance, on a typical window frame the beads are fitted to the inside. Minimal widths of about 50 mm are thus possi ble. The further development of this form of clamping led to the patent glazing wings and caps (fig . C 1 .34 a) . These are mounted from outside, which allows both thermal problems to be red uced and also the fixing of two panes simultaneously. Patent glazin g wings/caps are max. 40 mm wide. This category also includes structural sealant glazing (SSG) . The structural bond between g lass and frame achieved with special sil icone adhesives results in completely flat facade surfaces broken up only by the joints, and with no fixings visible on the outside. In Germany this technique is not permitted above hei g hts of 8 m without add itional mechanical retention of the outer pane (metal sections).

Cable net designs The desire of architects to "dissolve" the glass facade more and more led to the development of the so-called cable net in the mid-1 980s (fi gs C 1 .36 a and b). The loads are carried by pre­ stressed cables. Such designs are primarily loaded in tension and req u i re strong abutments to accommodate the prestress in the cables. Fixing

Owing to the specific characteristics of g lass, it must be fixed in such a way that there is no contact between the glass and other hard materials, both when loaded or as a result of thermal movement. The glass is therefore sup­ ported on permanently res i l i ent intermediate pads or layers. We d isti n guish between inter­ mittent and continuous forms of support (fig . C 1 .35) . Water that cannot drain away properly leads to ponding, which can cause permanent "fogging" of the g lass. It must there-

Intermediate support I n this form of support the g lazing is fixed at individual points by clamp-like fixings or coun­ tersunk screws (figs C 1 .34 b and c). In princi­ ple, the clamping arrangement is better for the material because drilling through glass can lead to detailing problems. Discrete fixings in

��10a9 tJicht m&r "w iw@telQl/11It 11!Jl i!I�/tiIt.�i "

W§'f 'll fll ��)e\ilW\Wsljm r#!I �k�lc.�i'lw.i¥fWti

a

c

C 1 .36

117

The building envelope

drilled holes are usually attached to brackets called spiders. These metal components collect the forces from several glass support points and transfer them to the load bearing construction . Solar energy aspects

G lass enables the passive use of solar energy as it allows the solar radiation to penetrate into the building interior. However, glass is also a major component in active solar energy sys­ tems. I n order to minimise the transmission heat loss­ es in winter and the risk of overheating in sum­ mer, the passive use of solar energy requires the relationship between available solar radia­ tion, size of openings, heating requirements, shading systems and thermal storage masses to be balanced. I nstal l i n g solar energy systems in the building envelope converts the facade from a passive, protective enclosure to an active, energy-producing element. Generally, we distinguish between two active forms of solar energy usage: photovoltaic systems, for generating electricity (fig . C 1 .37) , and thermal energy systems, for generating heat. The archi­ tectural integration of these solar energy sys­ tems i nto walls and roofs results in the compo­ nents acting simultaneously as energy-produc­ ing, constructional , functional and architectural elements in the design of the building envelope. Photovoltaic systems There are currently two strategies for integrat­ ing photovoltaic systems into the facade. One of these strategies involves positioning the semi-transparent solar cells (the transparency of which is constantly being improved) in such

External wall claddings Layers • for origin of data see "Life cycle assessments", p. 1 00

a way that the g lass surfaces still possess a certain transparency. The other strategy employs opaque solar cells with d ifferent col­ ours in order to the increase the design options with this material. The cells - originally dark blue - are now avai lable in various shades of blue, red and green , also in a yellow-gold col­ ouri n g . The shape of photovoltaic modules employing vapour deposition techniques can be varied and thus used as a further architec­ tural device. The degrees of efficiency of photovoltaic modules are as follows: • • •

·

crystal l ine sil icon cells, 1 2-1 7%, amorphous s i l i con cells, 5 -7%, copper indium seleni d e (CIS) cells, approx. 1 1 % cadmium tel luride (CdTe) cells, 7%.

Thermal energy systems Developments in the field of thermal energy systems are following a similar pattern to those of photovoltaic systems. Thermal energy sys­ tems use air or water as the heat transport medium and were ori g i nally black, but now the range of colours includes shades of blue, red , brown, green, gol d , si lver a n d light grey. How­ ever, the new colours do not achieve the degree of absorption of the black material; the energy gains are reduced by 2 -1 0% depend­ ing on the colour. The degrees of efficiency of thermal energy systems are in the region of 50-75% for flat­ p late collectors, whereas vacuum collectors achieve values of up to 80% .

C 1 .37 C 1 .37

C 1 .38

PEI primary energy non-renewable [MJ]

PEI primary energy renewable [MJ]

suspended stone slabs, limestone'

1 68

17

limestone slab, cut, 30 mm stainless steel fasteners (V4A) , 1 40 mm

•

stone slabs bedded in mortar, limestone'

71

limestone slabs, cut, 20 mm lime-cement mortar MG 1 1 , 1 5 mm

•

Photovoltaic panels integrated into the building envelope, Mont-Cenis Training Academy, Herne, Germany, 1 999, Jourda & Perraudin, Hegger Hegger Schleiff Life cycle assessment data for external wall claddings

GWP AP ODP global acidificaozone warming depletion tion [kg C02 eq] [kg R 1 1 eq] [kg S02 eq]

EP eutrophication [kg PO.eq]

POCP Durability summer smog [kg C2H.eq] [a]

10

0.060

0.0030

0.0040

0

0

0

0

0.026

0.0020

0.0020

80- 1 00

0.0 1 9

;;, 80

Stone 0

80- 1 00

0

3.5

5.4 0

Materials with mineral binders in situ concrete

680

in situ concrete, reinforced, 2% steel (FE 360 8) , 1 00 mm concrete anchor, high-alloy steel, 1 20 mm

-

fibre-cement sheets'

88

five-cement sheets, 8 mm timber supporting construction, 30 mm

•

calcium silicate units, with ventilated cavity

320

calcium silicate units (KS Vb 20/1 .8) , mortar MG 1 1 , 1 1 5 mm wall ties, steel , 80 mm

-

118

36

55

0

0.21

0.Q1 5

c:=J

c::::::J

c::::J

38

3.4

0

0.030

0.001 7

0.0020

40-60

10

33

0

0.082

0.0086

0.Q 1 8

60-80

0

Cl

c::J

c:::::::J

The building envelope

External wall claddings Layers • for origin of data see "Life cycle assessments", p. 1 00

PEI primary energy non-renewable [MJ]

PEI primary energy renewable [MJ]

GWP global warming [kg C02 eq]

ODP ozone depletion [kg R1 1 eq]

AP acidification [kg S02 eq]

EP eutrophication [kg PO.eq]

POCP Durability summer smog [kg C2H.eq] [a]

facing masonry, with ventilated cavity

400

9

51

o

0.10

0.0053

0.0080

solid clay bricks (VMz 28/1 .8). mortar MG 1 1 , 1 1 5 mm wall ties, steel, 80 mm

-

o

o

o

0. 1 1

0.0053

0.0080

o

o

o

0. 1 5

0.0095

0.0 1 4

Cl

CJ

CJ

0. 1 5

0.0093

0.0 1 3

Cl

CJ

CJ

0.16

0.0097

0.01 3

o

CJ

CJ

0.20

0.014

0.0 1 8

CJ

=

=

Ceramic materials

ceramic panels, with ventilated cavity

285

VFH ceramic panels, 30 mm aluminium sections, 60 mm

-

50

21

o

=

o

60-80

;, 80

Glass profiled glass, single-leaf'

532

profiled glass (channel). 498 x 41 mm, glass 6 mm thick aluminium frame, silicone joint, 40 mm

-

toughened safety glass'

531

toughened safety glass, 6 mm patent glazing bar, aluminium, EPDM gasket, 40 mm

-

insulating glass Ug = 1 . 1 '

547

double glazing, argon filling, 24 mm patent glazing bar, aluminium, EPDM gasket, 40 mm

-

insulating glass Ug = 0.7"

837

triple 91azing, argon filling, 36 mm patent glazing bar, aluminium, EPDM gasket, 40 mm glass double facade

59

28

o

28

o

o

62 o

65 o

70

=

29

o

=

40

o

o

50-80

50-80

50

50

2 1 62

353

131

o

0.76

0.041

0.055

50

832

1 68

55

o

0.34

0.01 7

0.023

70- 1 00

0. 1 1

0.0075

0.010

60-80

o

o

o

1 .29

0.016

0.030

80- 1 00

0. 1 5

0.0075

0.0 1 0

70 - 1 00

o

o

o

0.12

0.0057

0.008

o

o

o

0.01 6

0.001 7

0.004

toughened safety glass, 6 mm aluminium supporting framework, 250 mm double glazing, argon filling, 24 mm Metal corrugated aluminium sheeting corrugated aluminium sheeting, 1 mm aluminium supporting construction, 30 mm

=

trapezoidal steel sheeting, coated

452

trapezoidal steel sheeting, coated, 0.75 mm galvanised steel supporting construction, 30 mm

-

copper sheet

1 091

9.6

24

o

41

60

0.000040

copper sheet with double welt standing seams, 0.7 mm particle board P5, 22 mm

c:=====rI D

titanium-zinc sheet'

416

sheet titanium-zinc with double welt standing seams, 0.7 mm particle board P5, 22 mm

_

stainless steel sheet'

319

43

25

33

19

0.00001 4

0.00001 1

stainless steel sheet with double welt standing seams, 0 . 7 mm _ particleboard P5, 22 mm

80- 1 00

Timber wooden shingles/shakes

41

226

red cedar shakes, single-lap tiling, 16 mm timber supporting construction, 48 mm

-21

o

=

weatherboarding

73

larch weatherboarding, dispersion glaze, 24 mm timber supporting construction, 30 mm

•

plywood

1 89

building-grade veneer plywood, 1 6 mm timber supporting construction, 30 mm

-

40-70

o

459

-43

o

0.029

613

-29

o

0.066 o

o

0.28

0.0 1 8

40-70

0.0034

0.009

o

D

0.0075

0.033

40-70

0.049

25

Synthetic materials plastic sheet

1 099

63

52

four-walled sheet, polycarbonate, 40 mm patent glazin9 bar, aluminium, EPDM gasket

o

=

For plasters, renders and thermal insulation composite systems, please refer to "Surfaces and coatings", p. 201 . C 1 .38

119

The building envelope

"00

'0 55

ft �

o o ��_________________

Thatch Reed, straw Flat overlap. elem. Stone slabs laid loose Wooden shingles/shakes Natural/fibre-cement slates Clay/concrete tiles Clay/concrete tiles Pro!. overlap. elem. Glass, plastic Flat sheets Profiled sheets Fibre-cement Metal Metal with welted joints Sheets Bitumen Flexible sheeting Plastics, rubber

Couple roof Framing in plane of roof Purlin roof Vertical framing with king post In situ concrete roof standard applications with additional measures

C 1 .39 Relationship between material and roof pitch C 1 .40 Green roofs, office building, Vienna, Austria, 2001 , Oelugan-Meissl C 1 .4 1 Systematic classification of materials according to principle of roof covering and roof waterproofing C 1 .42 Jointing principles: a overlapping flat elements b overlapping profiled elements c welted joints (sheet metal) d clamping of flat sheets e soldering of sheet metal f welding and bonding of flexible sheeting

C 1 .39

Roofs

The roof, as part of the building envelope and loadbearing structure, shelters the building and its occupants from the effects of the weather. It protects against precipitation, carries wind , snow and imposed loads, and is part of the thermal insulation system. There is a complex relationship between building utilisation requirements, types of construction and roof forms. This is illustrated by the many d ifferent types of roof influenced by cultural develop­ ments, regional materials, manual techniques and industrial developments, e.g. the thatched couple roof, or the industrially prefabricated flat roof. Design principles

The overall roof construction generally consi sts of various layers, each of which fulfils one or more specific tasks, e . g . wearing course, cov­ ering layer, waterproofing layer, load bearing layer (e. g . battens, boards) , ventilation cavity, insulation layer, loadbearing structure and inner lining. The schematic detailed drawings on p p . 1 22 ,

1 26 and 1 28 show typical examples of the above layers and the options for variations withi n the roof system. I rrespective of type of covering, material and roof pitch, we can d istin­ g u i sh between single- and double-skin roofs. Double-skin roof The double-skin roof is also known as a venti­ lated roof or cold deck. The typical characteris­ tic according to 01 N 41 08-3 is a ventilated air layer d i rectly above the layer of insulation (fig . C 1 .43) . This air layer g uarantees the removal of any water vapour from the interior that m ight d iffuse through the insulation. This concept only works if the cross-sectional size of the air layer is adequate and there is an uninterrupted flow of air between the inlets and outlets. Single-skin roof The sing le-skin roof is also known as a non­ venti lated roof or warm deck. The roof covering or waterproofin g lies immediately on top of the layer of insulation. A vapour barrier on the inside prevents water vapour reaching the insu­ lation (fig . C 1 .44) .

The disadvantages of the double-skin roof cor­ respond to the advantages of the single-skin roof as g iven here: •

•

•

• • •

The overall depth of the roof construction is reduced. The absence of an airflow means there is no accelerated heat transport. The roof construction is not subjected to any moisture, timber components do not require any chemical preservatives. Ventilation openings are not required. Fewer layers means simpler penetrations. All the building performance requirements can be integrated into one component (e.g . compact roof) .

Covering and waterproofing

The uppermost layer of the roof generally pro­ tects the building against preci pitation. Depending on the roof covering material and roof pitch, there are basically two ways of pre­ venting the ingress of preci pitation: fast drain­ ing from the building (pitched roofs) , or creat­ i n g a barrier and draining the water to prede­ fined points (flat and shallow-pitched roofs). This results in the terms defined in DIN 4 1 08: "covering" is a layer of overlapping compo­ nents, and "waterproofing" is the sealed bond­ ing of sheet materials. The denser the materials and the tighter their joints with one another, the shallower the pitch can be. Fig. C 1 .39 illus­ trates the relationship between material and roof pitch. Jointing principles

The primary classification of the materials for roof covering and roof waterproofing is carried out accordi n g to their form (fig C 1 .41 ) . Funda­ mental methods for jointin g , junctions and fix­ ing can be derived from this classification and explained by means of examples. The list of potential materials is constantly increasing due C 1 .40

1 20

The building envelope

Materials for roof covering and roof waterproofing

Roof covering

Thatch

Diminishing roof pitch Flat overlapping elements

Profiled overlapping elements

reed

wooden shakes/

clay roof tiles:

straw

shingles

pantiles

slates

flat pan tiles

fibre-cement slates

under- and over-tiles

asphalt shingles

Roman tiles French tiles

clay: wire-cut tiles pressed tiles bullnose tiles concrete roof tiles stone metal

interlocking pantiles interlocking flat pan tiles adjustable head lap tiles

Flat sheets

I I

L_ _ _ _ _ �

glass plastic

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ •

Profiled sheets

I I

Sheets

L_ _ _ _ _ �

corrugated fibre­

aluminium

cement sheets corrugated bitumen sheets corrugated plastic

lead

sheets

Roof waterproofing

Flexible sheeting bitumen

copper

synthetic materials:

stainless steel

thermoplastic/

galvanised steel

elastomeric sheeting

zinc

membranes

aluminium galvanised steel coated and galvanised steel copper stainless steel

concrete: Roman tiles double Roman tiles

C 1 .41

to regional differences and the appearance of new products. Overlapping joints Roof coverings consist of individual compo­ nents that are laid in an offset, overlapping arrangement so that they drain the rainwater. Together with an appropriate roof pitch, this type of joint results in a rainproof but not water­ proof roof. Additional layers provide further pro­ tective functions, e . g . against drifting snow and driving rain. •

•

·

Flat overlapping elements such as wooden shingles or clay bull nose tiles require a steep roof pitch because otherwise water can pass through the side joints and reach the layers underneath. Multiple overlapping both parallel with and transverse to the roof slope guaran­ tee that the water is drained reliably. Thatched roofs are based on the same, overlapping principle. Profiled overlapping elements have a form that prevents water penetrating the side joints. The simplest are the under- and over-tiles: the under-tiles (tegula) form a channel to drain the water, the over-tiles (imbrex) cover the space in between. Double Roman tiles and other special forms have interlocking ribs on one or more s i des, this enables shallower roof pitches because each tile covers the head, tai l and side joints and presents an effective barrier to water. Welted seams are used to join sheet meta l . The side joints o f the sheet metal lie above the water run-off leve l . The pieces of sheet metal are bent up and over (stand i n g seam) , or the bent-up edges are covered by an add itional strip of metal (batten roll seam) . The transverse joints are in the form of overlaps, welted seams and steps in the fal l , which drain the water reli­ ably. The principle of the welted seam is simi­ lar to that of the profiled overlapping element.

Sealed joints Roof waterproofing materials form a coherent waterproof layer. Large-format sheets, sheet metal and flexible sheeting have fewer joints and are thus suitable for sealed joints. ·

•

·

Flat sheets of glass and plastic or sandwich panels are joined together with metal sec­ tions. With the help of patent glazin g wings! caps and resilient gaskets made from syn­ thetic materials, they form a watertight layer. Sheet metals can be joined together and made watertight by solderin g , stai n less steel sheets by wel d i n g . Apart from stainless steel, this form of jointing is only suitable for smaller areas and elements because temperature­ related changes in length can cause restraint stresses. Flexi ble sheeting and membranes based on bitumen, synthetic materials and rubber can be bonded together to form watertight over­ lapping joints. Solvents d issolve the surface structure of polymers (solvent welding). Hot­ air or flame guns reverse the structure of the material so that it acts like an adhesive. These two techniques are used to waterproof roofs and basements reliably.

a

p

b

/

Roof covering c

Roofs > 5° pitch can be covere d . Every roof covering material is assigned to a range of roof pitches at which the material can be properly laid (figs C 1 .39 and C 1 .47) . Although the materials for roof coverings and external wall claddings can be identical, in order to emphasise the character of the enclos­ ing envelope, the roof surfaces are exposed to the weather to a greater extent than the walls. Accordingly, the materials for the roof coverin g must be o f a better qual ity s o that the roof can satisfy all requirements.

d

@L

•

e

C 1 .42

1 21

The building envelope

C 1 .43 Single-skin roof construction, pitched, covering of 6 4 Water

Water

/

o o o o o

o o o o

Heat

Vapour

2 3 4 5 6 7 8

Roof covering Separating layer Boarding Ventil. air cavity Sheathing Thermal insulation Vapour barrier Loadbearing structure C 1 .43

The local conditions led to d ifferent forms of roof over the course of the centuries. For exam­ ple, in reg ions with heavy snowfall, roofs must be conceived differently to roofs in windy areas. Likewise, even today the availability of regional building materials and the typ ical col­ ours dominate the appearance of whole roofs­ capes. Even social standing is reflected in the choice of roof form, either to give the buildings of important persons more prominence ( e . g . domes) or t o al low ideological viewpoints a form of expression. "Why do we have the p itched roof? Some peo­ ple believe it is a matter for romance and aes­ thetics. But that is not the case. Every roofing material demands a certain angle . . . . Apart from small tiles and sheets we had no other means of protecting us from rai n , snow and storms . . . . Of course, the best solution always seemed to be a roofing material consisting of just one piece. Such a roofing material would need only the angle necessary to allow the water to drain away naturally." (Adolf Loos: " D i e moderne Siedlung", lecture, 1 926) Roof forms The simplest form of pitched roof is the mono­ pitch roof, and a row of monopitch roofs pro­ duces a sawtooth roof. In Central Europe the duopitch roof - in the form of (close) couple and purl in roofs - is the most common form. The hipped roof is among the oldest forms.

o o

Heat

Vapour

2 3 4 5 6 7 8 9

Roof covering Tiling battens Ventil. air cavity Sheathing Boarding Ventil. air cavity Thermal insulation Vapour barrier I n ner lining C 1 .44

Curved roof forms such as barrel vault, dome and onion play special roles. Every roof form calls for the specific design of its constituent parts. Appropriate laying tech­ niques g uarantee a rainproof result, and there are even complete roofing systems with which manufacturers can provide solutions with differ­ ently shaped parts. These special parts form the edges of the roof surface (ridge, verge , eaves) and ensure that they function correctly. They also i ncorporate i nto the roof surface openings such as roof windows, chimneys and other penetrations. The recommended roof pitch is the lowest angle at which a certain type of roof covering has proved to be rainproof without fixi n g ele­ ments and special seals. Thatch

Reed and straw are laid in the form of long bundles with a d iameter of 1 40-1 70 mm. They are fixed to the horizontal battens with tyi n g wire and sways (small sticks) in individual, overlapping layers starting at the eaves and proceed i n g towards the ridge. No tying wire should be visi ble on the surface of the roof. The thickness of thatch is approx. 350 mm for reed, approx. 300 mm for straw (fi g . C 1 .46 a) . The chimney must pass through the ridge. Dor­ mer windows are roof openings that req u i re a steep pitch and rounded junctions to prevent ingress of rainwater. A double-skin roof con­ struction (pitch � 45°) prevents a build-up of

C 1 .45 1 22

sheet metal with welted joints (schematic) C 1 .44 Double-skin roof construction, pitched, covering of interlocking plain clay tiles (schematic) C 1 .45 Sheet metal covering, Pavilion, Zeewolde, Netherlands, 2001 , Rene van Zuuk C 1 .46 Various types of roof coverings: a thatch b natural slates c asphalt shingles d plain (bullnose) clay roofing tiles, double-lap tiling e profiled wire-cut interlocking concrete roof tiles f interlocking profiled (flat pan) clay roofing tiles g corrugated metal sheets, stainless steel h sheet aluminium with locked double welt standing seams

moisture and rotting of the covering. A thatched roof of reed will last between 30 and 50 years provided it is regularly main­ tained, constant ventilation is ensured and moss and pests are removed . Reed and straw belong to building materials class B3 (highly flammable). Wooden shakes and shingles

High-qual ity, slow-growing species of wood with fine growth rings (without sapwood) are used for producing split shakes or sawn shin­ g les. We disti n guish between nai ling and laying loose. Shakes/shingles for laying loose are 600-900 mm long, 70-300 mm wide and at least 1 5 mm thick. They are laid offset with an overlap and are wei ghted down with heavy stones, and are therefore only suitable for roof pitches of 1 7-22°. They shou ld be taken up, turned over and reversed, and relaid after 51 0 years. Nailed shakes/shingles can have a tapered or parallel form, are 1 20-800 mm long and 60350 mm wide. They should be m i n . 8 mm thick at the tai l . Nailed shakes/shing les are fixed to battens on counter battens with clout nails; fix­ i n g d i rectly to the loadbearing board ing is not recommended because there is no airflow under the shakes/shingles and that compromis­ es their durability. The durabi l ity of a double-lap tiling arrange­ ment of wooden shakes/shingles in years is roughly equal to the roof p itch in degrees, but 70 years is the maximum. A proper roof construc­ tion requires no chemical timber preservative.

The building envelope

Natural and fibre-cement slates

The clayey shale obtained from quarries is split into approx. 5 mm thick slates at the works. German slates have a blue-grey to black colour depending on the reg ion from where they are obtained . Other countries can supply red or dark green slates. Fibre-cement slates are nor­ mally grey in colour, but can be dyed or g iven a coloured coatin g . They are 4 mm thick. I n both these materials, components for the gen­ eral roof surface and roof edges are given their form in the works by milling or punching , by cutting to a template, or manually. Natural slates are normally supplied with holes, but can be supplied without. Fibre-cement slates are supplied with holes. The shape of the slate determines the form of roof covering: rectangular double-lap, diago­ nal, German (curved or scalloped, equal sizes ) , or Old German (scal loped, unequal sizes ) . The course o f slates are l a i d in a bond either horizontally or at an angle, on battens or board­ ing (fig. C 1 .46 b). They are fixed with nails, clips or hooks. The larger the ind ividual slates, the lower the pitch can be.

•

•

minimum overlap is determined by the spac­ ing of the battens. Two nibs on the underside of each tile prevent them slipping down the roof (fig . C 1 .46 d ) . I n crown tiling two rows of bullnose tiles are hung on every batten with a half-tile offset. The course on the next batten repeats the pattern of joints to g ive a straight line from eaves to ridge. I n slip tiling there is no offset between individ­ ual courses and 50 mm wide slips are placed beneath the side joints so that rainwater can­ not penetrate. The slips should not be visible on the roof surface.

In addition, all side and transverse joints can be "torched", i .e. filled with mortar, either from outside during lay i n g , or from i nside after­ wards. This mini mises the ingress of rai n , snow and dust and also bonds the clay tiles together. Clay tiles are usually simply laid on the roof construction. However, as the roof pitch increases, so wind suction has a greater effect and can lead to tiles uplifti n g . I n such cases it is necessary to fix the tiles with nails, screws or c l i ps .

Asphalt shingles

Also known as strip slates, these are basically the same material as flexible bitumen sheeting (see "Bituminous building materials", p. 64) and are 3-6 mm thick. A surface finish of coloured mineral granules or chippings provides protec­ tion against ultraviolet radiation. The shingles are available in formats of approx. 1 000 mm wide x 336 mm lon g . Two or three slits across the width gives them their shingle-like appear­ ance. Asphalt shing les are laid in a double-lap arrangement offset by half or one-third of an individual shingle and fixed with clout nails (fig . C 1 .46 c) . Self-adhesive strips (melted b y the action of solar radiation) on the top of the shin­ gles bond the shing les together. Asphalt shingles require a rigid supporting construction made from tongue and groove boards or wood-based boards. A layer of flexi­ ble bitumen sheeting nailed to the board i n g serves a s sheathin g . Asphalt shingles w i l l last about 3 0 years provid­ ed dust and dirt, which could form a substrate for plants, is cleaned off regularly. Flat overlapping clay roof tiles

Flat clay roof tiles are available without i nter­ locking ribs (bullnose tiles ) , with deep side ribs (wire-cut interlocking tiles) or with ribs on all sides (flat pressed interlocking ti les) (see "Ceramic materials", pp. 5 1 - 53 ) . The ribs pro­ vide an overlap in both d i rections. They deter­ mine the form of laying and the typical appear­ ance of the respective type of til i n g . When using clay roof tiles without any ribs, the tile size, roof pitch and type of tiling define the min­ imum overlap for the tiles. The following forms of tiling are used:

Flat overlapping concrete roof tiles

Concrete roof tiles are g iven a acrylate-styrene­ based coati ng to protect the concrete against the effects of the weather and mechan ical damage. Pigments can be added d uring mix­ ing to provide colour. The surface finish resem­ bles that of fired clay roof tiles. Flat concrete roof ti les have deep twin side ribs and tai l ribs, and the special elements for edges, roof pene­ trations, etc. match these. They are laid l i ke clay roof tiles; the format of the concrete roof tile determines the spacing of the battens and the overlap. Coverings of clay or concrete roof tiles do not req u i re any reg u lar maintenance. However, some care over the years (depend­ ing on the degree of soiling) will increase their longevity beyond 50 years, but junctions may require repairs in the meantime.

Bullnose tiles in double-lap tiling form a half­ tile bond. They are hung on batten s and the

r

-

,

..\l

�

�

.'

, �

IJ

e

J

!

I�

l'

,

Profiled overlapping clay roof tiles

The multitude of d ifferent clay roof tile shapes and their dimensions depend on the manufac­ turers - the standards specify only the require­ ments for the material itself (fig C 1 .46f. The same is true for concrete roof tiles. A general classification into basic forms is therefore help­ ful: •

·

• •

d

Clay roof tiles without i nterlocking ribs include under- and over-tiles, clay flat pan tiles and pantiles. If manufactured with nibs, these clay tiles can be laid dry d i rectly on the battens, or in mortar. Headlaps and side laps depend on the shape of the tile. On pantiles the right corner at the head and the left corner at the tai l are splayed to avoid a four-tile overlap at the corners. In the case of Roman and double Roman tiles and i nterlocking pantiles, it is the interlocking ribs that determine the direction of laying,

h 1 23

The building envelope

Building Max. materials load class [N]

Bending Tensile strength strength

Rec. roof pitch [0]

Weight per unit area [kg/m ']

Thermal conductivity [W/mK]

Water vapour diffusion resistance

Reedlstraw Wood shakeS/shingles (2-lap) Natural slates Fibre-cement slates Asphalt shingles (single-lap) Corr. fibre-cement sheets Corrugated bitumen sheets

;, 45 ;, 22 ;, 22 ;, 22 ;, 1 5 ;, 1 0 ;, 7

70 25 45-60 25-40 15 20-24

0.04--0.07 0.1 1 . 2-2 . 1 0.58 0. 1 6 0.58

1 /2 40 800/1 000 70/ 1 30 virt. vapourtight 70/ 1 30

B3 B2; B1 A1 A2 A2 A2 A2

Flat clay roof tiles bullnose wire-cut interlocking pressed interlocking

;, 40' ;, 35 ;, 25

60-75

1 .0 1 .0 1 .0

30/40

A1

;, 600 ;, 900 ;, 900

Flat concrete roof tiles with deep side rib

;, 25

60- 65

1 .5

60/ 1 00

A1

;, 800'

Profiled clay roof tiles under- and over-tiles pantiles interlocking flat pan

;, 40 ;, 35 ;, 30 ;, 22

gO

1 .0 1 .0 1 .0 1 .0

30/40

45 55 55

A1 A1 A1 A1

;, ;, ;, ;,

Profiled concrete roof tiles flat pan

;, 22

55

1 .5

60/100

A1

;, 800'

15 60 1 09 1 60-235 293-385

virt. virt. virt. virt. virt.

vapourtight vapourtight vapourtight vapourtight vapourtight

A1 A1 A1 A1 A1

470-700 270-500 ;, 1 50 90-230 200-300

virt. vapourtight

A1

270-500

Roof covering

Sheet metal (double welt standing seam) ;, 7 30 stainless steel ;, 7 30 galvanised steel 30 zinc ;, 7 25 ;, 7 aluminium copper 30 ;, 7 Metal sheets galvanised steel

;, 1 0

1 5 -30

60

[-]

[N/mm>] [N/mm>] 38-52 40-87 1 6 -28 1 6 -28 1 2 .2

1 000 1 200 1 200 1 200

8-30 8-30 8 - 30

8 - 30 8 - 30 8 - 30 8 - 30

, For crown and double-lap tiling: ;, 30 mm. , Depends on the cover width: ,; 200 mm cover width = max. load ;, 800 N; ;, 300 mm cover width = max. load ;, 1 200 N; intermediate values may be interpolated. 3 Owing to the specific material properties. the strength is measured differently (see "Bituminous materials". p . 65). C 1 .47

usually from right to left. Sometimes tiling with an offset bond and a variable head lap is possible. . Tiles with an adjustable head lap enable the overlap at the head of the tile to be varied by up to 30 mm despite the presence of head and tail ribs.

Precut splayed corners prevent four-sheet overlaps at the corners. The sheets are fixed to the supporting con­ struction with screws, at least four per sheet, through the crests of the corrugations. A seal­ ing washer/cap between fastener and sheet prevents ingress of water.

Profiled overlapping concrete roof tiles

Corrugated bitumen sheets

Concrete roof tiles cure after being moulded and hardly shrink during production (fig . C 1 .46e). I n some more elaborate forms of concrete roof tile, e . g . double Roman, the tail ribs interlock with the head ribs of the tile below and there­ fore can be laid dry while still attaining a good level of rainproofin g . They are laid in a similar way to profiled overlapping clay roof tiles.

Plain sheets made from cellulose fibres are impregnated with bitumen , shaped in presses and allowed to dry. Coatings on an acrylic resin basis give the sheets their colour and also help to protect the surface. The maximum size avail­ able is 2000 x 1 060 mm, and the sheets are 2.4- 3.0 mm thick. Edge and special compo­ nents p l us translucent corrugated sheets of PVC or g lass fibre-reinforced polyester resin are also available. Corrugated bitumen sheets are laid offset with the corrugations parallel to the slope so that rainwater can drain away easily. The side over­ laps are equal to one corrugation. The end lap of 1 40 - 1 60 mm depends on the roof pitch. The sheets are fixed through the crests of the corru­ gations with non-rusting nails with a PVC head, or countersunk-head nails with a sealing wash­ er. Run-off water that has drained across corru­ gated bitumen sheets can cause corrosion on unprotected metal parts, e . g . roof gutters, which must be avoided at all costs. The sup­ portin g construction of battens or boards must al low for ventilation of the sheets.

Corrugated fibre-cement sheets

Owing to their large format (up to 2500 mm long and 1 097 mm wide) , corrugated fibre­ cement sheets can provide a rapi d covering to roof pitches � 7°. They are divided i nto stand­ ard-pitch and narrow-pitch types. The latter have more corrugations than standard-pitch sheets (over the same width), but are not as deep. Special components for edges, junctions and special purposes (e. g . translucent sheets of glass fibre-reinforced plastic) complement the range of standard sheets. The sheets are laid starting at the eaves and proceeding towards the ridge, usually from right to left.

1 24

Profiled metal sheets

Profiled metal sheets can be made from galva­ nised, stainless or duplex-coated ( galvanis­ ing + powder coating) steels, aluminium alloys or copper. The shaping of the flat sheet metal, 0.5- 1 .5 mm thick, produces planar compo­ nents with various trapezoidal, corrugated or ribbed profiles, also metal panels. Composite panels are produced by enclosing insulating material between two metal sheets. The pro­ d uction process limits the width to about 1 200 mm, the length is limited by the transport restrictions. The side overlaps of these sheets are equal to one rib or corrugation. The fixing to the sup­ porting structure is by way of screws, rivets or c l i ps through the crests. Elongated holes and sliding fixings are used to accommodate tem­ perature-related changes in length. Additional sealing washers prevent the ingress of wind and water (fig . C 1 .46 g ) . =

Sheet metal

Flat sheets of aluminium, lead, copper, stain­ less stee l , galvanised steel and zinc are availa­ ble in rolls. The minimum roof pitch is 3°, but r is recommended because standing water can penetrate through the seams. Furthermore, as it evaporates, the water can leave behind aggressive substances on the surface of the metal. Rainproof side joints between the bays of sheet metal are ensured with single, double or locked double welt standing seams, or vari­ ous batten rol l s and, for sheet lead only, hol low or wood-cored rolls (fig . C 1 .46 h ) . All the differ­ ent types of side joints make use of the same bent-up edge, which can be bent by hand or machine. C l i ps fixed to the supporting con­ struction are fitted into the side joints to create a structural connection to the supporting con­ struction. Nevertheless, they sti l l permit chang­ es in length caused by temperature fluctua­ tions. The transverse joints are overlapped and welted. Sheet metal roof coverings are very durable (70 -80 years for copper, lead and stainless steel) and are suitable for shallow pitches and curved surfaces. The width of the sheets and the material chosen g ive the final roof surface its characteristic appearance. Double-skin roof constructions prevent a build-up of moisture below the vapour-tight metal covering. The supporting construction is usually made from timber boards.

The building envelope

Roof waterproofing systems

Flexible synthetic and rubber sheeting

Flexible bitumen sheeting

made from polymer­ modified bitumen

with thermoplastic elastomers Elastomer bitumen sheeting

with thermoplastic elastomers Elastomer bitumen sheeting

Polyisobutylene

Butyl rubber

Unplasticised polyvinyl chloride

Ethylene-propylene-diene rubber

Ethylene copolymer bitumen

Chlorosulphonated poly­ ethylene

Ethylene-vinylacetate terpolymer Chlorinated polyethylene

with thermoplastic materials C 1 .4 7 Physical parameters of roof coverings C 1 .48 Systematic classification of roof waterproofing systems

Plastomer bitumen sheeting

Roof waterproofing

Flat and shallow-pitched roofs require a water­ proofing or sealing layer because water cannot drain away quickly enough. This watertight layer covers the entire roof surface and includes penetrations and junctions. The sur­ faces of flat roofs can be used in many ways, e.g. as open landscaped areas, for parkin g , as circulation areas in urban surroundings (e.g. above basement parking), or as rooftop gardens. Flat and shallow-pitched roofs

The term "flat roof" is difficult to define precise­ ly. We can class roofs with a p itch 5: 5° as flat, and those with pitches up to 25° as shallow­ pitched. However, the German Flat Roof Guide­ lines speak of flat roofs with waterproofin g but without stating an angle. In order to avoid ponding, the fall of the roof should be at least 2%. Shallower falls must be regarded as spe­ cial constructions. The multitude of possible types of construction for flat and shallow-pitched roofs is due to the number of layers, which perform various func­ tions and together form that complex system known as a flat roof. Single-skin designs are favoured in practice. These can be classed according to the position of the roof waterproof­ ing within the system of layers. Conventional flat roof The waterproofing lies above the thermal insu­ lation. A vapour barrier must be i ncluded to protect the insulating material against moisture from the interior of the building. Depend i n g on the method of laying the waterproofin g , gravel can be used as protection against wind suc­ tion, heat and ultraviolet radiation (fig . C 1 .49) . Should any leaks occur, water tends to seep underneath the layers of the conventional flat roof.

made from elastomers (rubber sheeting)

made from thermoplastics (synthetic sheeting)

Flexible unsaturated poly­ ester resins Flexible polyurethane resins Flexible polymethyl methacrylate

Chloroprene rubber Thermoplastic elastomers

Alloys of flexible polyolefins

C 1 .48

Compact roof The compact roof is simi lar to the conventional flat roof. Cellular g lass slabs laid in hot bitumen serve as thermal i nsulation, and a vapour barri­ er is unnecessary. This plus the fully bonded flexible waterproof sheeting prevents any water seepi n g underneath. Upside- down roof I n this roof the insulation is laid above the waterproofing and therefore protects it against mechanical loads. The loosely laid insulating material should not absorb any water, and it is usually made from expanded polystyrene (EPS) . Grave l , stone/concrete flags or planting secures the insulating material against wind suction and upl ift. The roof waterproofing func­ tions both as drainage level and vapour barrier (fig . C 1 .50) . Duo-roof/plus-roof The duo-roof is a combination of conventional flat roof and upside-down roof. There are two layers of thermal insulation - one above and one below the waterproofing . If a roof is given a new layer of insulation ( e . g . in the case of add­ i n g rooftop plantin g ) , this is known as a duo­ roof. In the case of refurbishment work, this type of roof is known as a plus-roof when a new layer of waterproofing is laid on top of the exist­ i n g , insulated roof construction, and further insulation is laid on top of this.

Flexible bitumen sheeting

Bituminous sheeting consists of a backing soaked in straight-run bitumen and coated on both sides with a facing layer of blown bitumen. Sheeting made from polymer-modified bitumen uses strai g ht-run bitumen (including thermo­ plastic or elastomeric additives) for the facing layer and for soaking the inlays. Depending on the type of sheeting, a surface finish protects against ultraviolet radiation (see "Bituminous materials" , pp. 64-65). Bituminous sheeting is suitable for waterproofing roofs and basements. Laying Bituminous waterproofing can only claim to be permanently watertight when at least two layers are used, one on top of the other, which are bonded or welded together to form a homoge­ neous layer. The following methods have become establ ished in practice: ·

•

•

Flexible waterproof sheeting

Flexible waterproof sheetin g can be d ivided into bitumen, synthetic (thermoplastics) and rubber (elastomers) groups. Each group has its specific properties, resulting in different meth­ ods of working and different arrangements. Provided they are compatible, different types of flexible waterproof sheeting can be combined.

•

Pouring and rol ling: the (polymer-modified) bitumen sheeting is rolled out and pressed down into a hot bitumen compound that is poured ahead of the material. There must always be a continuous bulge of compound just ahead of the rol l of material. Felt torching: the underside of suitable sheet­ ing can be melted with a propane gas torch as it is unrolled and pressed down onto the roof surface. Mop p i n g : the hot bitumen compound can be spread over the roof before unrolling the sheetin g . There must always be a continuous bulge of compound just ahead of the roll of material. Cold a p p l i cation: self-adhesive sheeting has an adhesive appl ied to the underside of the sheeting by the manufacturer.

Depending on the type of roof construction, the first layer of sheeting can be fully bonded to the substrate or just with spots or strips of bonding

1 25

The building envelope

Water

1

compound. If mechanical fixings are being used , the first layer of sheeting is laid loose. Overlaps at all joints must be at least 80 mm. To avoid multiple overlaps at the same place, further layers are laid with a corresponding off­ set, but parallel with the first layer. From a material point of view, it is also possible to combine d ifferent types of flexible bitumen sheetin g , or to lay a combination of synthetic and bitumen sheetin g . However, compatibility between the d ifferent types must be assure d .

2 3 4 5

•

•

•

BV - bitumen-compatible NB - not bitumen-compatible P - plasticised K - lamination V - reinforcement E - inlay GV - glass fleece GW - glass cloth PV - polyester fleece PW - polyester cloth PPV - polypropylene fleece

o

1 2 3 4 5

Heat Vapour

Ballast Waterproofing Thermal insulation Vapour barrier Loadbearing structure

Flexible synthetic a n d rubber sheeting

C 1 .49 Water

1

2 3 4 5

,

Heat

o o

Vapour

,

/

Synthetic and rubber sheeting can be used for waterproofing roofs and basements. D I N 1 8 53 1 and 1 8 1 95 specify the materials, applications, dimensions and laying tech­ niques. Synthetic and rubber sheeting is made from thermoplastic and elastomeric materials respectively, with or without a backin g . Tear resistance, tear propagation, temperature-relat­ ed changes in length and how the sheeting adheres to the substrate are all influenced by the backing. Although sometimes referred to as a plastic fi l m , this is incorrect because films are max. 0.8 mm thick, and the thickness of this sheetin g is 1 -3 mm. Sheeting pre-joined at the works to cover a large area is also available.

·

•

•

1 2 3 4 5

Ballast Waterproofing Thermal insulation Vapour barrier Loadbearing structure C 1 .50

C 1 .49 Conventional flat roof (schematic) C 1 .50 Upside-down roof (schematic) C 1 .51 Roof waterproofing with flexible synthetic sheeting at pipe penetration C 1 .52 Physical parameters of roof waterproofing systems

Properties I n contrast to flexible bitumen sheeting, the synthetic sheeting is normally resistant to ultra­ violet radiation. In addition, it and its welded seams exhibit good root resistance. However, a single layer of waterproofing is vulnerable to mechanical damage, but this can be prevented by a layer of loose gravel with rounded grains ( 1 6/32 mm), or plantin g . A m u ltitude of prefabri­ cated special components is available, e . g . junctions for internal a n d external corners, roof vents, drainage outlets, etc. Such components ease the waterproofing of complex roof geometries. Some types of sheeting made from thermoplas­ tic materials are resistant to chemicals - with the exception of some solvents. They can be heated up and moulded in order to waterproof complicated details and junctions. Once the material cools, it sol idifies again. Owin g to their Iow-density cross-linked molecu­ lar structure, sheeting made from elastomeric materials has a rubbery elastic nature and can­ not be remoulded upon heatin g . However, its resistance to chemicals and solvents and its good d urab i l ity with respect to environmental influences make this a very d urable form of roof waterproofing . Types of sheeting A typical standardised sheeting designation would be D I N 1 6 734-PVC-P-NB-1 .5-V-PW. This describes the standard , type of material, specific properties, sheeting thickness in milli­ metres, sheeting make-up and type of inlay:

C 1 .5 1

1 26

Applications Owing to the multitude of different types of sheetin g , the manufacturers must specify prod­ uct-related properties and hence the applica­ tions. In principle, the following applies:

•

Non-laminated, unreinforced sheeting types without an i n lay are rarely used in practice. However, they are suitable for roofs with a complete, uniform covering (e. g . flags, grav­ el), bonded laying methods or for waterproof­ ing basements. A lamination on the underside of the sheeting improves the adhesion characteristics for full or partial (spoVstrip) bonding and can protect the sheeting against a rough substrate. The improved tear resistance of types of sheeting with a cloth inlay are suitable for use with mechanical fixings because the inlay diminishes the resilience of the sheeting. Fleece inlays likewise reduce the resilience. On roofs with a complete, uniform covering ( e . g . flags, gravel), sheeting with a fleece i nlay is usually preferred .

Laying Roof waterproofi n g with synthetic and rubber sheeting is usually carried out with just one layer of material. Separating layers between sheeting and substrate prevent chemical reac­ tions in the case of i ncompatib i l ity (e.g. between PVC sheeting and polystyrene insula­ tion or bitumen) . Fixing Mechanical fixings are suitable for sheeting with a high tear strength and for lightweight supportin g constructions. The mechanical fix­ ing comprises fixing bars or fasteners in the substrate consisting of fastener plus retaining washers. The fasteners are positioned at a reg­ ular spacing along the edge of the sheeting and are welded to the next piece of sheeting with an overlap. Continuous metal sections or strips are positioned at the necessary spacing and covered with additional strips of sheeting approx. 200-250 mm wide. The number of fix­ ings depends on the wind suction loads calcu­ lated. Full or partial bonding is carried out with hot bitumen and polyurethane adhesives, which bond the sheeting to the substrate. In the case of bituminous adhesives, the bitumen compatibility must be checke d . Some types o f sheeting a r e manufactured with a self-adhesive coating on the back for full

The building envelope

Flexible sheeting

Bitumen Uncoated bitumen-saturated sheeting Bitumen roofing felt with felt inlay Bitumen roofing felt with glass fleece base Bitumen sheeting for waterproofing of roofs Bitumen waterproof sheeting for felt torching with jute cloth with glass cloth with glass fleece with polyester fleece Flexible bitumen sheeting with metal inlay

Abbreviation

DIN

Service temperature [OC]

R 500 N R 500 V 1 1 ; V 13

52 1 29 52 1 28

0-70 0-70

Max. tensile force [N] long. trans.

Max. elongation Min. tearing Elongation strength [N / mm>] at tear [%] [%] trans. long. trans. long. trans. long. 1 .5 2 2

1 .5 2 2

350 300 400

200 200 300

600 1 000 400 800 500

500 1 000 300 800 500

2 2 2 40 5

3 2 2 40 5

1 000

1 000

2

2

800

800

40

40

200

200

1 50

1 50

52 1 30;

J 300 DD; J 300 84; J 300 85 G 200 DD; G 200 84; G200 85 V 60 84 PV 200 DD; PV 200 85 Cu 0.1 0; AI 0.2 0

Polymer-modified bitumen Polymer-modified bitumen sheeting­ for waterproofing of roofs Polymer-modified bitumen waterproof sheeting for felt torching with glass cloth PYE-G 200 DD; PYE-G 200 84; PYE-G 200 G5; PYP-G 200 84; PYP-PV 200 85 with polyester fleece PYE-PV 200 DD; PYP-PV 200 DD; PYE-PV 200 85; PYP-PV 200 85 Cold-applied self-adhesive K8K bitumen sheeting

52 1 3 1

1 8 1 90-4

0-70

0-70

52 1 32 52 1 33 (PYE) - 25 - 1 00; (PYP) - 1 5 - 1 30 1 8 1 95-2

Thermoplastics Ethylene copolymer bitumen Ethylene-vinylacetate Chlorinated polyethylene Polyisobutylene Polyvinyl chloride, unplasticised

ECB EVA PE-C PIB PVC-P

1 6 736 1 6 731 1 6 730

depends on depends on depends on depends on depends on

Elastomers Chloroprene rubber Chlorosulphonated polyethylene Ethylene-propylene-diene rubber Isobutylene-isoprene rubber

CR C8M EPOM IIR

7864 1 6 733 7864 7864

- 20 to 70 - 20 to 70 - 20 to 70 - 20 to 70

1 6 732

product product product product product

3 - 3.5 4-10 12 4.5 10-18

3-3.5 4-10 12 4.5 1 0 -1 8

400-600 300-500 > 330 350 250-360

8.5 13 5 - 9.8 7.5-8

6.9 15 5-9.8 7.5-8

280 280 > 550 > 800 350-540 350-540 > 450 > 450

400-600 300-500 > 330 350 250-360

C 1 .52

bonding to the substrate. Roof waterproofing beneath a complete, uniform covering (e.g. planting, gravel) can dispense with fixings and bonding provided the load of the covering can withstand the wind suction forces. Jointing The quality of the overall roof waterproofin g depends on t h e quality o f the seams. This calls for careful cutting of the sheeting (especially at the edges) , avoiding folds, creases and ten­ sion, and ensuring that the sheeting is turned up 1 00-1 50 mm above the top of the roof fin­ ishes at all junctions and terminations. Sheeting made from thermoplastic materials can be connected homogeneously with suita­ ble solvents (solvent welding. In doing so, the overlap should be approx. 50 mm, depending on the type of fixing (min. 30 mm for a welded seam) . Hot air (temperature at nozzle approx. 600°C) can be blown into the overlap to weld the sheeting together. Using a roller, the softened sheeting is then pressed together to form a welded jOint min. 30 mm wide. Heat fusing with a heat gun uses the same principle. Owing to their cross-linked molecular structure, sheeting made from elastomeric materials can­ not be welded (exception: partially cross-linked

CSM and some other materials) . I nstead , a con­ tact adhesive is spread over the surfaces to be joined and once the adhesive has gone off, the sheeting is pressed together with a m i n . 50 mm overlap. Hot vulcanising is suitable for off-site prefabrication. The seams produced using this method have the same properties as the sheet­ i n g itself.

Roofs for circulation

Waterproofed surfaces on buildings and civil engineering works can be used as circulation areas (e.g. flat roofs and basement parki n g ) . Besides the structural load-carrying capacity, they require a suitable finish that is not con­ nected directly to the structure and also pre­ serves the flexible sheetin g . An upside-down roof can be used to provide permanent protec­ tion for the high-quality flexible sheetin g . Finish­ es for roofs with foot traffic can be d ivided into three groups depending on type of layin g , type of jointing and the contact with the roof water­ proofing. Permanent finishes Cement screeds, asphalt and flags in mortar are among the permanent roof finishes. I n

order to avoid stresses, movement joints must be i ncluded at certain intervals. The finishes must be laid to a fal l of � 1 .5% so that surface water can drain readily. Loose finishes Like in the building of footpaths, flags (e.g. con­ crete or stone) and paviors (e.g. concrete, stone or timber) can be laid in a bed � 50 mm thick that allows some movement. The bed con­ sists of sand (risk of washing out, poor water seepage) or fine gravel or chippings separated from the layer of sand by a non-woven fabric fil­ ter. The advantage of this is that it allows some of the water to seep away. An additional drain­ age mat carries the seepage water to gutters or outlets. It i s not essential to lay the finishes to a fal l . Raised finishes I n this case a finish of stone/concrete flags of timber is raised above the roof waterproofing. Provided the underlying layers have sufficient compressive strength, the advantages of this type of construction are its low self-weight, q u ick installation and absence of fal l s because the water simply drains through the open joints onto the roof waterproofing below and from there flows to the concealed outlets. Simple

127

The building envelope

(fig . C 1 .55). Such plants demand specific sub­ strates and thicker layers, and they must be constantly cared for and watered. Layers

Heat

1 2 3 4

o o

Vapour

Plants Plant-bearing layer Filter fleece Drainaqe laver

if required 6 Waterproofing 7 Thermal insulation 8 Vapour barrier

C 1 .53

sawn timber is used under the uprights, or mor­ tar sacks or height-adjustable supports with an X-joint. Numerous systems are avai lable on the market.

Green roofs

By adding landscaping and plantin g to roofs, it is possible to gain multiple uses from roofs over private or public areas. Besides the aesthetic aspects, the areas of greenery and planting can provide leisure and recreation zones. From the ecological viewpoint, landscaped surfaces on structures improve the microclimate of the urban environment by evening out temperature peaks, increasing the humid ity of the air and bonding dust and d i rt better than gravel-cov­ ered roof surfaces. Furthermore, areas of p lant­ ing protect the roof waterproofing against u ltra­ violet radiation. Owing to their layer of vegeta­ tion, green roofs are classed as combustible. They must therefore satisfy requirements regarding distances from neighbouring build­ ings and they require incombustible thermal insulation. The additional layers for the planting increase the thermal insulation effect and func­ tion as a basin for retaining precipitation water - they store the water and release it again later. Flat and shallow-pitched roofs up to approx. 25° are suitable for planting. The steeper the slope, the greater is the work req u i re d to retai n the water a n d prevent slippage. We d istinguish between extensive and intensive rooftop plant­ ing irrespective of the function of the area.

Starting with the standard construction of the single- and double-skin roof, further layers are added in order to meet the req u i rements for a green roof. Sometimes ind ividual layers provide more than one function, in other cases not all functions are req uire d . The sequence of layers from outside to inside is, in principle: plants, plant-bearing layer, filter, drainage layer, pro­ tection mat, root barrier, separating layer, waterproofing (fig . C 1 .53) . Basically, it is also possible to add planting to an upside-down roof. Plants Moss and sedum varieties plus many plants that seed themselves or form shoots spread out over the roof surface according to season and weather conditions. A permanently green sur­ face can only be achieved with intensive rooftop planting, which is then akin to a garden.

layer because such particles would impair the drainage function. If the grains of the plant­ bearing layer are coarse and those of the drainage layer fine, the drainage layer act as a filter. Loose mineral materials, boards and non­ woven fabrics (PA, PP, PET, glass fibre or rock­ wool) are available for use as filters. Drainage layer The excess water seeping down from the plants is carried away to outlets and g utters via the drainage layer in order to avoid a build-up of water. At the same time, the drainage layer has the task, through a medium pore size, to store some of the seepage water for the plants. Roots then penetrate the drainage layer. It cor­ responds to the natural subsoil and can be classified in a similar way to the plant-bearing layers: •

•

Plant-bearing layer The plant-bearing layer (substrate) has the task of storing or draining water, retaining nutrients and providing a firm hold for the roots of the plants. The thickness of the layer, the particle size and form, the constituents and its water retention capacity determine the plant varieties that can be planted. On pitches � 1 5° a vegeta­ tion mat prevents erosion of the substrate . The different plant-bearing layers are classified according to form and composition: ·

•

•

loose materials with varying organic and inor­ ganic proportions and porous structures, e . g . mineral-organic soil mixes, humus, lava mixes, pumice, expanded clay slabs of mineral wool or mineral-enriched polyurethane foam mats of natural and synthetic fibres together with loose materials

•

Depending on the roof pitch, uncrushed (<;; 5°) and broken (<;; 20°) loose m ineral materials can be used. On roof pitches > 20° additional grids of battens are required to prevent slip­ page. Drainage mats of expanded polystyrene (EPS) , bitumen-bonded extruded polystyrene beads (XPS) and mou lded, foamed boards can be used , even for roof pitches exceeding 20°, provided they are secured against slip­ page. Mats of textured non-woven fabric, embossed sheets (PE, rubber) or welded, recycled fla­ kes of plastic foam (PE) exhibit a good drai­ nage performance for a minimum thickness ( 1 0-35 mm). However, they store little or no water.

Root barrier The long-term root penetration resistance of waterproof sheeting depends on its composi­ tion. If sheeting and seams are not permanently resistant to root penetration, metal or polyester i nlays in bitumen sheeting or an additional root barrier (e. g . polyethylene sheeting) will be required over the entire roof surface.

Filter The filter layer prevents fine particles seeping from the plant-bearing layer into the drainage

Extensive rooftop planting This type of planting requires less work during preparation, establishment and subsequent care because only low-level , droug ht-resistant plant varieties are chosen and the roof con­ struction comprises only thin layers. This type of planting is often used on pitched roofs or added subsequently to gravel-covered flat roofs (fig . C 1 .54) . Intensive rooftop planting I ntensive planting includes shear-resistant grass zones suitable for foot traffic, p lus taller grasses and shrubs, even ind ividual trees C 1 .54

1 28

C 1 .55

The building envelope

Membranes

Coated cloth

PVC-coated polyester cloth

Uncoated or impregnated cloth

PTFE-coated glass clotht

silicone-coated glass cloth Laminated cloth

Film

PTFE-Iaminated glass cloth

In the construction industry we associate the term membrane with lightweight, long-span sur­ faces in tension made from thin, light-permea­ ble textiles or films. Membranes are used in conjunction with cables in tension and steel, concrete or timber columns in compression. During the 1 950s, at the same time as develop­ ments in synthetic composite materials, engi­ neers began to develop membranes as protec­ tion against the weather and solar radiation or as temporary roofs. In addition, the develop­ ment of new materials and multi-layer mem­ branes have made permanent roof construc­ tions possible that can comply with complex building performance requirements.

PTFE cloth cotton cloth monofilament cloth made from fluorocarbon resins perforated ETFE film perforated PC film

Low-e glass cloth

Stainless steel fabric Gas-tight membrane material

PTFE-coated ow-e glass cloth

C 1 .56

Materials

Isotropic materials exhibit approximately identi­ cal mechanical properties in all d irections. Such materials include metal foils and thermo­ plastic materials. Textiles form the foundation for membranes made from anisotropic materials. They are d ivided into three groups accordi n g to their method of manufacture: ·

·

PU-coated polyester cloth

fluoropolymer-coated low-e glass cloth

tion, e . g . sphere, dome or cylinder. Such forms req u i re a supporting construction which is sur­ rounded by the membrane, or pneumatic pres­ sure from inside that tensions the membrane. Anticlastic forms are surfaces curved in two directions; they are inherently stable and require no supporting structure (e. g . hyperbolic paraboloid ) .

·

PC capillary­ structure mat

Sound insulation membranes

Internal

Forms

Membranes can only accommodate tensile forces. As the tensile forces of the spanned surfaces in plane structures approach infinity and wind and precipitation cause severe oscil­ lations and deformations, membrane construc­ tions require three-dimensional, prestressed or pre-curved planar geometries. We disti nguish between synclastic and anticlastic forms. Syn­ clastic forms are surfaces curved in one direc-

Thermal insulating material

Externallinternal

inseparable glass cloth polyester cloth

ETFE film THV film PVC film

Membranes

Special materials

Open-pore materials

Closed-pore materials

mesh products (knitted fabrics) woven products (cloths) non-woven products (fleeces, felts, nets)

As cloths consist of warp and weft threads in an approximately orthogonal arrangement, exhibit a non-linear force-elongation progres­ sion and are non-elastic, they are i deal for carrying loads.

The yarns used can be made from the following fibres: · • · ·

Depen d i n g on the type of weave, the untreated cloth exhib its anisotropic properties, i.e. d iffer­ ent mechanical parameters in the warp and weft d irections. Uncoated cloths are an end product i n themselves. A coating of PVC, silicone or PTFE can be added to both sides of the cloth after pretreat­ ment to im prove the adhesion of the coating. Coatings protect the cloth against moisture (g lass cloth), ultraviolet radiation (polyester cloth), fire and infestation by microorganisms. They thus improve the durability and soiling behaviour of the membrane materials. Coated cloths can be welded as well as sewn and g lued together. In order to refine the surface finish and improve the soiling and cleaning characteristics, mem­ branes can be additionally sealed with materi­ als based on fluoropolymers or acrylic resins.

C C C C C

C 1 .58

natural fibres mineral fi bres metallic fi bres fibres from thermoplastic materials

Single-skin green roof construction (schematic) Extensive rooftop planting Intensive rooftop planting, raised roof finish Systematic classification of membrane materials PVC-coated polyester cloth, roof to main grandstand, sports stadium, Oldenburg, Germany, 1 996, Architektengemeinschaft Marschweg­ stadion C 1 .58 PVC-coated glass-fibre cloth (two layers, pneu­ matic), velodrome, Aigle, Switzerland, 2002, Pascal Grand

1 .53 1 .54 1 .55 1 .56 1 .57

1 29

The building envelope

Weight per unit area

Membrane

[g / m2] Film ETFE film

THV film

Uncoated cloth cotton cloth

50 �m 80 �m 1 00 �m 1 50 �m 200 �m 500 �m

350 520 300 520 710

PTFE cloth

Coated cloth PVC-coated polyester cloth

PTFE-coated glass cloth

87.5 1 40 1 75 262.5 350 980

Type I Type I I Type I I I Type IV Type V Type VI

silicone-coated glass-fibre cloth PVC-coated aramid-fibre cloth THV-coated ETFE cloth

800 900 1 050 1 300 1 450 2000 800 1 1 50 1 550 800 1 270 900 2020 250

Ten_ strength based on D I N 53353 (guide only) [N / 5 cm]

Translucency Building Buckling materials resistance class [- to 0]

[%]

UV resist_

Durability

[- to 0]

[a]

up to 96

64/56 58/54 58/57 58/57 52/52 22/21

B1 B1 B1 B1 B1 B1

1 700/1 000 2500/2000 2390/22 1 0 3290/3370 4470/45 1 0

B2 B2 A2 A2 A2

varies varies up to 37 up to 37 up to 37

3000/3000 4400/3950 5750/5100 7450/6400 9800/8300 1 3 000/1 3 000 3500/3500 5800/5800 7500/6500 3500/3000 6600/6000 7000/9000 24 500/24 500 1 200/ 1 200

B1 B1 B1 B1 B1 B1 A2 A2 A2 A2 A2 B1 B1 B1

up to 20 up to 1 7.5 up to 1 5 up to 1 2.5 up to 1 0 up to 7.5 15 12 8 up to 25 up to 25 basically zero basically zero up to approx. 90

0

0 0

up to approx. 95

0

>

25

>

20

<5 >

25 25 25

>

20

>

25

>

20

> >

0 0 0 0

0 0

> >

20 25

C 1 .59 Physical parameters of membrane materials C 1 .60 PTFE-coated glass-fibre cloth, carport, municipal waste management depot, Munich, Germany, 1 999, Ackermann & Partner

C 1 .59 C 1 .61 ETFE foil cushions, Allianz Arena, Munich, Ger­ many, 2005, Jacques Herzog & Pierre de Meuron C 1 .62 Life cycle assessment data for roof coverings and roof waterproofing systems

Applications and properties

Material categories

Membranes can be erected considerably faster than conventional roofs because the material is cut to size and all the edges are prepared prior to delivery. Owing to the low weight of 200-1 500 g / m2, movable roofs like the tennis court at Rothen­ baum, Hamburg, Germany (see Example 25, pp. 261 -63) , and long-span structures free from intervening columns can be erected. Multi-layer membrane systems satisfy add ition­ al thermal insulation criteria (U-values from 2 . 7 down to 0.8 W/m2K); they also improve the sound insulation. Transparent films have a higher UV radiation permeability than glass, which can be an advantage for indoor swimming pools and greenhouses. Multi-layer, pneumatic, prestressed membrane constructions made from films (cushions) pro­ vide thermal insulation in conjunction with good translucency and transparency. In a three-layer arrangement the pneumatic adjustment of the middle layer results in different degrees of l i g ht transmission when the middle and u pper mem­ branes are printed with offset l i g ht-reflective patterns. Membrane systems for the active use of solar energy are currently undergoing development.

Membrane materials can be classed as water­ tight, closed-pore, and water-permeable, open­ pore materials because the watertightness is usually the primary application criterion.

130

C 1 .60

Closed-pore materials The technical properties of PVC-coated polyes­ ter cloth and PTFE-coated g lass cloth enable them to be used externally as protection from the weather. PVC-coated polyester cloth with various surface finishes is suitable for movable and reusable membrane constructions thanks to its good buckl i n g resistance. It is not read ily flammable and, at 1 5 -20 years, relatively long­ lastin g . PTFE-coated g l ass cloth is incombusti ble and will remain serviceable for more than 25 years. It has a self-cleaning surface and owing to its coatin g does not absorb any moisture. The translucency can be controlled between 0% and 50% by adjusting the density of the cloth and the thickness of the coating. However, it is less elastic and less resistant to creasing than PVC-coated polyester cloth . Factors such as draft desig n , structural calcu­ lations and functional requirements determine the choice of material just as much as the anti­ cipated module sizes. PVC-coated polyester

C 1 .61

cloth can be prefabricated in sizes up to 1 0 000 m2. By contrast, owing to the handling during production, PTFE- or ETFE-coated glass-fibre cloth is available only in sizes up to 2500 m2. Together with ETFE films, PTFE- or ETFE-coated glass-fibre cloth and PVC-coated polyester cloth account for approx. 90% of all membrane constructions. The d urab i l ity of ETFE films is about 25 years. They are primarily used for pneumatic, trans­ l ucent constructions and are readily printed. Their high shear strength calls for very precise cutting during fabrication to create irregular and curved shapes. THV film (tetrafluoroethy­ lene hexafluoropropylene vinylidine fluoride copolymer) has a lower tear strength but is more elastic and easier to work. The elongation behaviour of PVC film varies considerably with the temperature and this film also has only a low strength. It is therefore used for internal applications only. Open-pore materials Uncoated PTFE cloth is ideal for movable con­ structions that do not have to be rainproof, e . g . folding membranes for shading systems. Cot­ ton cloth can be used temporari l y both internal­ ly and externally. The swelling behaviour of cot­ ton once it is wet provides the necessary rain­ proof effect. I nterior acoustics can be influ­ enced by using micro-perforated membranes made from cloth or film.

The building envelope

Roof finishes Layers ' for origin of data see "Life cycle assessments", p . 1 00

Roof coverings

flat plan tiles, titanium-zinc flashings

clay flat pan tiles, 20 mm timber battens, 24 x 48 mm polyethylene (PE-HO) sheathing, 0.5 mm concrete tiles, titanium-zinc flashings

concrete tiles, 20 mm timber battens, 24 x 48 mm polyethylene (PE-HO) sheathing, 0.5 mm titanium-zinc sheet

titanium-zinc with double-welt standing seams, 0.7 mm timber boards, 24 mm copper sheet'

copper sheet with double-welt standing seams, 0.7 mm timber boards, 24 mm

fibre-cement sheets', titanium-zinc flashings

corrugated fibre-cement sheets, 8 mm timber battens, 24 x 48 mm polyethylene (PE-HO) sheathing, 0.5 mm MOF board, 1 8 mm natural slates', copper flashings

natural slates, Old German slatin g , 5 mm flexible bitumen sheeting type V 1 3, 5 mm timber boards, 24 mm wooden shingles, copper flashings

wooden shingles, double-lap tiling, 24 mm timber battens, 24 x 48 mm polyethylene (PE-HO) sheathing, 0.3 mm timber boards, 24 mm asphalt shingles, titanium-zinc flashings

asphalt shingles, 3 mm wood fibreboard, 24 mm

PEI primary energy renewable [MJ]

331

1 80

-

288

-

458

c:::J

1 55 c:::::J

1 43

GWP ODP global ozone warming depletion [kg C02 eq] [kg R 1 1 eq]

AP acidification [kg S02 eq]

EP eutrophication [kg PO.eq]

POCP Durability summer smog [kg C2H. eq] [a]

11

0. 1 0

0.0053

0.0 1 2

0

=

0

0.00001 2

0.10

0.0061

0.01 2

0

0

c:::::J

0

0.0000 1 5

0. 1 6

0.0086

0.0 1 3

0

0

C=:::J

0

0.0 1 2

0.024

=

4

D

17

c::::::J

830

1 30

35

=

689

1 97

0

0.000033

26

0

=

999

1 38

24

0.000087

=

501

910

708

1 15

flexible bitumen sheeting , with gravel

gravel, 50 mm polyester fleece (PES), 2 mm flexible bitumen sheeting (PYE PY200 S5), 5 mm flexible bitumen sheeting (G200 S4), 4 mm PVC, with gravel

gravel, 50 mm flexible PVC sheeting, 2.4 mm perforated glass fleece, 3 mm polyethylene (PE-HO) vapour barrier, 0.4 mm EPDM with gravel

gravel, 50 mm flexible EPOM sheeting, 1 .2 mm perforated glass fleece, 3 mm polyethylene (PE-HO) vapour barrier, 0.4 mm PVC with extensive planting

mm

1 355

38

58

-44

848

28

69 0

0.21

0

0.65

22

40

0.0 1 4

0.028

c::==::::J

c:::::J

0.014

0.058

c::==::::J

c====J

0.50

0.01 0

0.026

D

c::::J

c::==:J

=

0.000086

0.33

0.013

0.057

c===J

c====J

0.0 1 9

0.091

, =

0

0.50 c::::J

27

0

17

=

46

0

0

50

70 80 40

70

40

25

25-30

1 1

0.20

0.0 1 4

0.022

0

c::==::::J

Cl

0. 1 3

0.0086

0.028

0

C=:::J

c:::::J

0.54

0.0 1 9

0.054

=

50

=

0.0000 1 9

0

394

, c====J

j c===J

0

394

.16

c:::J

Cl

Roof waterproofing systems

plant-bearing layer, 80 mm polyethylene (PE-HO) filter fleece, 0.1 expanded clay filter layer, 30 mm drainage mats, extruded polystyrene root barrier, polyester fleece, 1 .5 mm waterproofing, flexible PVC sheetin g , perforated glass fleece, 3 mm polyethylene (PE-HO) vapour barrier,

PEI primary energy non-renewable [MJ]

25-30

25-35

30-40

I c==:::J

(XPS), 30 mm

2.4 mm 0.4 mm

C 1 .62

131

Insulating and sealing

Since the dawn of industrialisation in the 1 8th century, the concentration of carbon dioxide in the atmosphere has increased by more than 30% and has probably never been higher in the past 20 million years. Beside emissions from intensive agriculture (methane and d i nitrogen oxide) , it is mainly the carbon d ioxide released into the atmosphere by burning fossil fuels that contributes to the greenhouse effect and hence to g lobal warming. I n Germany more than one-third of the energy consumed annually is used for heating build­ ings. Thermal i nsulating and sealing materials significantly reduce the heating requirements of both old and new buildings. Modern standards of thermal insulation save more energy than is req u i red for the production and transport of the i nsulating materials - at the latest after two heating periods. Cavities of stationary air behind timber planking and the double-leaf masonry that began to appear at the start of the 20th century are regarded as the first con­ structional measures aimed at i mproving ther­ mal insulation and moisture control. I nsulating materials made from wood-wool, cork and min­ eral fibres first became available during the 1 920s. However, until the 1 970s the primary task of passive thermal insu lation was to avoid damage to the building and g uarantee hygienic living conditions. Energy economy

C 2.1 C 2.2

C 2.3 C 2.4

132

Infrared image of buildings Systematic classification of insulating materials according to their raw materials Comfort zone depending on U-value of wall with an external temperature of - 1 0°C Thickness of insulation required to achieve a ther­ mal resistance of 0.3 W/m2K

As a result of the oil crisis, the rapid increase in the price of crude o i l and the associated reali­ sation that our consumption of energy must be red uced, Germany passed its first Thermal I nsulation Act in 1 977, which was updated in 1 982 and 1 994. The prime aim of the act was to specify maximum thermal transmittance values (U-values) in order to reduce the transmission heat losses through external building compo­ nents, and hence lower the heating req u i re­ ments. The Energy Economy Act in force since 2002 instructs users to consider the influence of the airtightness of the building as wel l by determining the ventilation heat losses. The airtightness of building envelopes with good thermal insulation has a decisive effect on the heating energy requirements (see p. 1 42 ) . I nsulation and airtightness concepts

C 2.1

must therefore be coordinated at an early stage as part of a hol istic approach to the desig n .

Insulation principles

The insulating effect of a material improves as the air pores in the material become smaller, more numerous and more evenly distributed; stationary air in the pores is always a poorer conductor of heat than the surround ing solid material. Accord i n g to D I N 4 1 08, building materials with a thermal conductivity A < 0 . 1 W/mK can be classed as thermal insulating materials (fig . C 2.4). Owing to the g rowing demand for insulating materials and the increasing requirements to be met by thermal insulation, the number of dif­ ferent insulating products on the market is con­ stantly ris i n g . Mineral-fibre insulating materials and expanded foam materials are the most popular, with a combined market share exceeding 90%. In recent years insulating materials made from renewable raw materials have been red iscovered, and their application options are g rowin g . I nnovative i nsulating materials s u c h a s vacuum insulation panels (VIP) or infrared absorber­ modified polystyrene insulating materials (see "The development of innovative materials", p . 29) achieve considerably better insulation values (fig . C. 2 . 7 ) . T h e building materials industry c a n supply numerous products for the thermal insulation of external wal l s that are both loadbearing and insulatin g , e . g . l i ghtweight vertically perforated clay bricks. But the i nsulating function does reduce the load bearing capacity of the materi­ al. These products are dealt with in "Ceramic materials" (see pp. 50-5 1 ) . Classification

I nsulating materials are d istinguished accord­ i n g to the raw materials on which they are based (fi g . C 2.2): • •

inorganic, m ineral insulating materials organic insulating materials

Both organic and inorganic insulating materials

Insulating and sealing

Insulating material Inorganic, mineral made from natural materials

Organic

made from synthetic materials

made from natural materials

expanded clay

frothed glass

cotton

natural pumice

ceramic insulating foam

granulated cereals

expanded perlite

foam made from kaolin or perlite vermiculite

calcium silicate

made from synthetic materials urea-formaldehyde resin in situ foam (UF)

flax

mineral wool (MW) made from glass wool or rock wool

expanded melamine resin foam

expanded phenolic resin foam (PF)

hemp

polyester fibres

wood shavings

cellular glass (CG)

expanded polystyrene foam (EPS)

wood fibres (WF)

vacuum insulation panel (VIP))

extruded polystyrene foam (XPS)

wood-wool slabs (WW)

expanded polyurethane foam (PUR)

coconut fibres

polyurethane in situ foam (PUR)

cork products sheep's wool

bulrushes

straw/straw lightweight loam peat

cellulose fibres

can be made from natural or synthetic raw materials. We disti n guish between the following types according to their structure: • · ·

fibre insulating materials foamed insulating materials granulateslloose fill

• •

Functions and requirements

Thermal insulation • ·

•

Once the building is complete, the insulating materials are normally "invisi ble" . They fulfil a number of tasks and functions:

·

the temperature of the interior air can be con­ siderably lower but still achieve the same level of comfort. If the temperature of the interior air is lower, then the transmission and ventilation heat loss­ es are also lower. Reducing the temperature of the i nterior air by 1 K achieves savings in heat­ ing req u i rements amounting to approx. 6%.

Besides clothing and physical activities, there are other variables that are significant for human beings' perception of comfort i n enclosed rooms. These are:

·

·

sound insulation (depending on material) protecti n g the construction against conden­ sation or frost

Thermal comfort

Fibre materials form a type of no-fines material and hence prevent airflows. In foamed materi­ als the fixed cell structure and the enclosed air, or special gases, prevent convection.

•

C 2.2

guaranteeing a comfortable and hygienic interior climate reducing the transmission and ventilation heat losses preventing overheating in summer

air movements humid ity of the interior air temperature of the interior air and fluctuations thereof mean internal surface temperature

The temperature-related comfort zone regard­ ed as agreeable for the majority of people has been d etermined through comprehensive stud­ ies (fig . C 2.3). The temperature of the interior air and the mean internal surface temperature both contribute to chilling and hence the per­ ception of comfort to roughly the same extent. In buildings with good thermal insulation, the higher i nternal surface temperatures mean that 30

-11 - --

-

��

ta

=

- 1 0°C C 2.3

�

!

! j'" ! al al � K K � .n .n

Thermal conductivity The outward flow of heat takes place by way of conduction, radiation and convection. As a building performance parameter, thermal con-

11

u

20 -

The quality of the thermal insulation is based on the thermal properties and dimensions of the building materials and components used. Dur­ ing periods of cold weather there i s a constant flow of heat from inside to outside via the build­ i n g envelope. The term "insulation" describes the principal function of thermal insulating materials - to reduce the heat flow through the building com­ ponent layers.

-

0

'"

o O-n-

o

U -

0

0 -

0 �o

0

-

'"

r---

-

0

1l

&1 iD

IIf. 133

Insulating and sealing

C 2.5

C 2.6

Applications for thermal insulation to D I N V 4 1 08-1 0, table 1 Differentiation of certain product properties to DIN V 4 1 08-1 0, table 2

Part of building

Abbreviation

Typical applications

Floor, roof

DAD DAA DUK DZ

External insulation to floor or roof, protected from the weather, insulation beneath covering External insulation to floor or roof, protected from the weather, insulation beneath waterproofing External insulation to roof, exposed to the weather (upside-down roof) Insulation between rafters, double-skin roof, uppermost floor not designed for foot traffic but accessible Internal insulation to floor (soffit) or roof, insulation below rafterslloadbearing construction, suspended ceiling, etc. Internal insulation to floor or ground slab (top) beneath screed, without sound insulation requirements Internal insulation to floor or ground slab (top) beneath screed, with sound insulation requirements

01

Wall

Perimeter

DEO DES

WAS WAA WAP WZ WH WI WTH WTR

External insulation to wall behind cladding External insulation to wall behind waterproofing External insulation to wall beneath render I nsulation to double-leaf wall, cavity insulation I nsulation to timber-frame and timber-panel construction I nternal insulation to wall I nsulation between party walls with sound insulation requirements Insulation to partitions

PW PS

External thermal insulation to walls in contact with the soil (outside the waterproofing) External thermal insulation beneath ground slab in contact with the soil (outside the waterproofing)

ductivity 'A [W/mKj groups these three heat transport mechan isms together. It should be remembered that the lower the thermal con­ ductivity, the better is the thermal insulating effect of a material. The properties of metals make them especially conductive, with values up to 400 W/mK. Vacuum inSUlation panels achieve values as low as 0.004-0.008 W/mK by employing the thermos flask principle (vacuum layer) . The classification of thermal insulating mate­ rials into thermal conductivity groups ( e . g . WLG 035 or WLG 040) valid hitherto h a s been superseded since the introduction of the Euro­ pean product standards. According to D I N 4 1 08-4 the designation uses the so-called design thermal conductivity value, which can be specified in 1 mW steps ( e . g . 'A 0.028 W/mK) . =

a comfortable i nternal climate even in the case of high external temperatures. Building materi­ als that store heat help to even out the weather­ and uti l isation-related temperature fluctuations over the day. The specific heat capacity c specifies the storage capacity of a building material. Owing to their low weight, most i nsu­ lating materials have only a low heat storage capacity. Heavy insulating materials such as wood fibre insulating boards (density > 1 00 kg / m3) can be used in areas where overheat­ ing is likely ( e . g . converted roof spaces) in order to improve the thermal insulation in sum­ mer through their high storage capacity. Moisture control

There is a strong correlation between thermal i nsulation and moisture contro l . At 1 5°C water 'A 0.598 W/mK has a thermal conductivity 25 times greater than that of air ('A 0.024 W/mK) . Consequently, any water in a building material significantly reduces its thermal insulation capacity. Furthermore, moisture in building components can lead to corrosion, mould g rowth and frost damage. I n organic i nsulating materials water contributes to decomposition and destruction of the materials. In winter in particular, there is a vapour pressure grad ient between a heated interior and the cold outside air. The diffusion of water vapour from inside to outside can lead to condensation within exter­ nal wal l and roof constructions (interstitial con­ densation) . Insulating materials used in the cavities of double-leaf walls must therefore be hydrophobic (water-repellent) over their entire thickness. =

=

Thermal transmittance value (U-value) The U-value is the building performance parameter indicating the thermal transmittance of building components and i s specified in W/m2K. The thermal insulating properties of different constructions can therefore be com­ pared directly. A low U-value signifies a low heat flow through the building components and hence lower heat losses (U unit of heat trans­ fer) . Wherever components with a good thermal conductivity (e.g. concrete balcony slabs with­ out a thermal break) penetrate the insulated external wal l , the material properties lead to thermal bridges. Besides i ncreased heat loss­ es, there is also the risk of mould growth caused by the condensation that can col lect at such places. =

Specific heat capacity D I N 41 08-2 contains recommendations for ther­ mal insulation in summer in order to g uarantee

134

Water vapour diffusion The �-value specifies the d iffusion resistance of a material and has no units. Accordi n g to D I N 4 1 08-4 i nsulating materials made from mineral wool (� 1 ) , for example, are very =

C 2 .5

open to d iffusion, but cellular glass on the other hand is practically vapourtight (� 1 00 000). When designing external components, the dif­ fusion resistance of the individual component layers should decrease from inside to outside. The quantity of water diffusing into and out of the i nsulating materials, and hence possible risks to the materials, can be checked using the Glaser method ( D I N 41 08-3 ) . =

Sound insulation

In building work we d i stinguish between insu­ lating materials for airborne and structure­ borne (impact) sound when discussing their acoustic insulation properties. In order to improve the airborne sound insula­ tion of lightwei g ht walls or voids, soft fibrous insulating materials with a high flow resistance are particularly suitable. Such materials reduce the sound energy (air pressure fluctuations) as it passes through the fibres by converting into kinetic energy. I nsulating materials for impact sound insulation ( e . g . beneath floating screeds) are always elas­ tic and must exhibit minimal dynamic stiffness in order to absorb the incident i mpact energy and transfer only a part of this energy to the underlyin g structure. Fire protection

Insulating materials are also suitable for use in preventive, passive fire protection concepts in order to protect building components against rapid temperature rises. The majority of inorganic insulating materials belong to building materials class A ( incom­ bustible), but organic insulating materials only class B (combustible) . Health and environmental issues

Even though insulating materials are not gener­ ally in direct contact with the interior air, the

I nsulating and sealing

Product property

Abbreviation

Description

Examples

Compressive strength

dk dg dm dh ds dx

No compressive strength Little compressive strength Moderate compressive strength High compressive strength Very high compressive strength Extremely high compressive strength

Insulation to voids, insulation between rafters Residential and office areas beneath screeds Roof not designed for foot traffic, with waterproofing Roofs for foot traffic, terraces Industrial floors, parking decks Heavily loaded industrial floors, parking decks

zk zg zh

No requirements regarding tensile strength Low tensile strength High tensile strength

Insulation to voids, insulation between rafters External insulation to wall behind cladding External insulation to wall under render, roof w. bonded waterproofing

tk

No requirements regarding deformation Dim. stability not affected by moisture and temp. Deforms under load and thermal stress

Water absorption

wk

wf

wd

Tensile strength Acoustic properties

sk sg sm sh

Deformation

tf

No requirements regarding water absorption Absorbs liquid water Absorbs liquid or diffusing wate

No requirements regarding acoustics Impact sound insulation, low compressibility Impact sound insulation, moderate compressibility Impact sound insulation, enhanced compressibility

amounts of hazardous substances they contain (e.g. formaldehyde, styrene, isocyanate, phenol; see "Hazardous substances", p. 268) should nevertheless be kept to a minimum. The discus­ sion surrounding the toxicity to humans of addi­ tives (flame retardants in organic insulating materials, pesticides in some organic insulating materials made from natural materials) is on­ going. These days, foamed plastics production mostly uses pentane (pure hydrocarbon) or carbon dioxide. The use of CFCs (chlorofluorocarbons) and partially halogenated HCFCs has been banned throughout Europe since 1 995 and 2002 respectively. As an alternative, some manufacturers use chloride-free HFCs, whose ban is currently a subject of debate. Owing to the proven health risks of asbestos fibres and dust in interiors, synthetic mineral fibres are also suspected of having a carcino­ genic potential. For this reason, in 1 995 the insulating materials industry switched the pro­ duction of mineral wool to non-inhalable fibre thicknesses (carcinogenicity index � 40) and reduced the bio-persistence of rock wool . Like with all other fibre insulating materials, it should ensured at the planning stage that no fibres can be released into the interior air.

All applications without acoustic requirements Floating screeds, party walls Floating screeds, party walls Floating screeds, party walls

Internal insulation External insulation to wall beneath render, roof with waterproofing Roof with waterproofing

ty ( e . g . dh high compressive strength) . Accord i n g to their method of supply and instal­ lation, we d istinguish between boards, mats, felt, packing woo l , loose fill and in situ foams. From the building performance point of view, thermal insulating materials should be attached to the cold side of the construction whenever possible. However, in order to reduce the transmission heat losses from old buildings with facades protected by preservation orders, internal insulation is often the only solution. This treatment lowers the temperature of the wal l construction o n the cold s i d e a n d considerably increases the risk of interstitial condensation. As a rule, internal insulation calls for an extremely carefully installed vapour barrier or vapour check on the inside (see p. 1 45 ) . More­ over, thermal bridges at the wall-floor junctions are practically unavoidable. An vapour d iffu­ sion analysis is essential when using internal i nsulation. =

When choosi n g a suitable insulating material, the constructional framework conditions, the technical rules and the respective requirements should be taken into account: ·

•

Applications

The harmonised insulating materials standards D I N EN 1 31 68 to 1 3 1 7 1 are pure product standards and specify properties and designa­ tions only. The applications for thermal i nsula­ tion (fig. C 2.5) and the differentiation of certain product properties (fig. C 2.6) are regulated at national level (in Germany D I N V 4 1 08- 1 0 ) . The type codes are in each case made up of the application (e.g. WAA external wall i nsulation behind waterproofing) plus the product proper-

Internal insulation for residential and office areas External insulation to external walls and roofs Perimeter insulation, upside-down roof

·

•

·

•

=

•

General requirements: d i mensions, density, properties (texture, edges, colour, etc. ) Strength: compressive strength or compres­ sive stress at 1 0% compaction, long-term compressive stress, tensile strength, adhe­ sive strength of foams Dimensional stability when subjected to the effects of heat and cold Thermal i nsulation: thermal conductivity, ther­ mal resistance, heat storage capacity Moisture control: water vapour permeab i l ity, hydrophobic properties, water absorption Sound insulation: dynamic stiffness, flow resistance Fire protection: building materials class,

· ·

•

C 2.6

upper service temperature limit Health and environmental issues Durability: ageing resistance, resistance to high humidity, thermal stabil ity, UV radiation resistance Economic factors

Fixing

We distinguish between the following types of fixing irrespective of the choice of insulating material: ·

•

•

loose: no permanent mechanical connection, e . g . tipped, packed, blown in, laid loose individual : permanent ind ividual or l i near fix­ ings, e . g . nailed, screw, dowelled, glued full bond : a connection over the entire area of the insu lating material, e . g . g lued (adhesive, bitumen) , bedded in mortar

Recycling

The type of fixing has a crucial i mpact on the later recyclability of an insulating material. Materials i nstalled loose can usually be very easily reused, but those installed with a full bond are impossible to reuse. The technical options for recycling the materi­ als have developed at a faster rate than their practical application. Normally, mineral insulat­ ing materials are still sent to landfill sites, organic insulating materials are incinerated .

Insulating materials

The technical parameters of insulating materi­ als shown in fig. C 2 . 7 represent guidelines; these should be compared with the actual product data provided by the manufacturer in each individual case. A selection of insulating materials is given below.

135

Insulating and seali n g

Insulating material

Vapour diffusion resistance index

[kg / m,,]

Design thermal conductivity value [W/mK]

Inorganic, made from synthetic materials calcium silicate glass wool/rock wool cellular glass (CG)

1 1 5 - 290 1 2 -250 1 00- 1 50

0.045 -0.070 0.035 -0.050 0.040-0.060

2/20 1 /2 virtually vapourtight

A1 -A2/to A1 A1 - 8 1 /to A1 A1 /A1

Inorganic, made from natural materials expanded perlite (EP8) expanded clay vermiculite

60-300 260-500 60- 1 80

0.050-0.065 0.090 - 0. 1 60 0.065-0.070

2/5 2 2/3

A1 - 82 / to A 1 A1 /A1 A1 /A1

Organic, made from synthetic materials polyester fibres expanded polystyrene foam (EPS) extruded polystyrene foam (XPS) expanded polyurethane foam (PUR)

1 5 -45 1 5 - 30 25-45 " 30

0.035-0.045 0.035-0.040 0.030-0.040 0.025 -0.035

20/ 1 00 80/250 30/ 1 00

8 1 -2/to 8 8 1 /t0 8 81 /to 8 81 - 2 /to 8

Organic, made from natural materials cotton flax granulated cereals hemp fibres wood fibre insulating board (WF) wood-wool slab (WW) wood-wool multi-ply board (WW-C) coconut fibres insulation cork board ( IC8) sheep's wool cellulose fibres

Density

�

[-]

20- 60 0.040-0.045 1 /2 25 1 /2 0,040-0,045 1 05 - 1 1 5 n.a. 0.050 0.040-0.045 20-70 1 /2 45-450 0.040-0.070 1 /5 360-570 0.065- 0.090 2/5 heavily dependent on lay-up of plies 50- 1 40 1 /2 0.045-0.050 80-500 0.040-0.055 5/ 1 0 1 /2 20 - 80 0.035 -0.040 30 - 1 00 0.035 -0.040 1 /2

"Innovative" insulating materials (organic/inorganic) IR absorber modified EPS 1 5-30 transparent thermal insulation vacuum insulation panel (VIP) 1 50-300

0.032 0.02 - 0 . 1 3 0.004- 0.008

20/ 1 00 virtually vapourtight virtually vapourtight

Building materials class 1

Standard

Product forms

D I N EN 1 3 1 62 D I N EN 1 3 1 67

board board, fleece, packing wool board, loose fill

DIN EN 1 3 1 69 DIN EN 1 4063

DIN EN 1 3 1 63 DIN EN 1 3 1 64 D I N EN 1 3 1 65

81 -82/to 8 81 -82/to 8 82/to D 82/to D 82/to D 81 /t0 8 8 1 -82/to 8 81 -82/to 8 81 -82/to 8 81 -82/to 8 81 -82/to 8

DIN DIN DIN DIN DIN

EN 1 3 1 71 EN 1 3 1 68 EN 1 3 1 68 1 8 1 65- 1 /-2 EN 1 3 1 70

DIN EN 1 3 1 63

81 /to 8 82/to D

board, loose fill loose fill loose fill

fleece board board board, in situ foam

mat, felt, pack. wool, blow-in prod. board, mat, felt, packing wool blow-in product, loose fill board board board board mat, felt, packing wool loose fill, board mat, felt, packing wool blow-in product, board

board panel panel

The building materials classes are given as a guide only; they must be compared with the actual product data. Insulating material with building authority approval. 3 The insulating material exploits the static insulating effect plus solar gains; the values given here include solar gains determined over one heating period in Germany. These figures can vary considerably depending on climate and the orientation of the insulation. 4 Insulating materials for transparent thermal insulation systems fall into building materials classes A 1 to 83 depending on the raw material. 1

2

C 2.7 Mineral wool (MW) made from glass wool or rock wool

In Germany mineral-fibre insulating materials account for about 60% of the market - the larg­ est share. In terms of raw materials and bond­ ing of the fibres, we d istinguish between glass wool and rock wool. Glass wool (fi g . C 2 . 8 a) normally consists of recycled glass (approx. 50% by mass), quartz sand, feldspar, sodium carbonate and lime­ stone. In addition there is 3-9% binder made from synthetic resins (usually phenol-formalde­ hyde) and approx. 1 % waterproofing agent based on a silicone or on mineral oil. Rock wool (fig . C 2.8 b) is mainly produced from natural stone (e. g . d iabase, basalt, dolo­ mite), but can also contain clay brick and baux­ ite constituents from production waste. The proportions of binder and waterproofing agent are somewhat lower than those of glass wool . Just 1 m3 of stone produces about 1 00 m 3 of rock wool . The production involves melting the raw materials and additives at 1 300-1 500°C, which produces a pulp to which the b inder is added. M ineral-fibre insulating materials have equally good thermal and sound i nsulation properties. They are open to diffusion and are regarded as highly durable thanks to their rotting and

136

weathering resistance. However, insulating boards must be protected against extreme moisture because otherwise their insulating effect and strength are substantially reduced.

lular glass is normally bonded to components with bitumen, recycling is virtually impossible. Applications peripheral basement insulation and insulation beneath load bearing ground slabs thermal insulation to surfaces with heavy com­ pressive loads ( e . g . industrial floors, parking decks) internal insulation cavity i nsulation flat and green roofs •

Applications . Thermal insulation, airborne and i mpact sound insulation, and fire protection in virtual­ ly all situations

•

·

Cellular glass (CG)

Also known as foam glass, this material (fig . C 2 . 8 c ) is produced l i ke normal glass b y heat­ ing the raw materials quartz sand, feldspar, calcium carbonate and sod ium carbonate at about 1 400°C. The proportion of recycled g lass may account for about one-third of the total mass of raw materials. After cooling, the g lass is m il led to form a powder and carbon is added as a blowing agent (hence the dark grey col­ our) before the powder is heated again. The oxidation of the carbon causes the formation of gas bubbles which foam up the fluid mixture. Owin g to its closed-cel l structure impervious to gas, cellular glass is practically vapourtight, completely unaffected by water and d imension­ ally stable. It is therefore mainly used for build­ ing components in contact with the ground or those subjected to compressive loads. As cel-

• •

Calcium silicate insulating boards

Calcium silicate insulating boards have only recently been launched on the market (also with the designation mineral foam), and provide an alternative to the conventional insulating materials in thermal insulation composite sys­ tems. The raw materials are quartz sand, hydrated lime, cement and a curing agent with hydro­ phobic properties; about 1 0% cellulose is added to boards for internal use. They are pro­ duced (formation of pores, hardening and dry­ ing) in autoclaves like aerated concrete. Calci­ um silicate insulating boards are very open to diffusion and thanks to their water absorption ability contribute to regulating the humidity of

Insulating and sealing

the interior air, which makes them suitable for use as internal insulation on external walls, When used external ly, the water absorption is reduced to s;; 5% by adding a waterproofing agent. If this insulating material is incorporated in a mineral wall construction, the complete wall can be disposed of as a whole, Owing to the higher density of calcium s i licate insulating boards, they seem clearly more massive than conventional thermal insulation composite sys­ tems, Applications external and internal insulation to walls fire protection •

•

Expanded perlite

Perlite (fig , C 2 , 8 d) is among the group of aqueous, vitreous rocks with a volcanic ori g i n , In the expanding process crushed raw perlite is briefly heated to about 1 000°C to g ive it a viscous consistency, The water in the rock turns to steam and expands the particles to max, 20 times their original volume, A silicone waterproofing agent or encasing in bitumen or a natural resin can be used depending on the intended use of the material, Loose fi l l perl ite treated with waterproofing agent is open to d if­ fusion, hardly affected by moisture and cannot rot. Expanded perlite is either combustible or incombustible depending on the encasing material. Expanded perlite boards (EPB) can be pro­ duced by addi n g binders plus organic and inorganic fibres, Applications lightweight aggregate for concrete and mortar cavity insulation thermal and impact sound insulation levelling layer beneath screeds loose insulation for roofs and timber joists floors •

·

·

•

•

Expanded clay

After the clay is obtained from open-cast m ines it is stored for about a year, The processing involves milling the raw material and passing it through a rotary kiln where it is dried using the countercurrent method and subsequently heat­ ed to approx, 1 200°C, at which temperature the bonded water turns to steam and expands the particles, Expanded clay does not rot and can withstand high compressive loads, However, the thermal insulation characteristics (approx, 0,09 W/mK) are rather poor when compared to other insu­ lating materials, Applications lightweight aggregate for concrete and mortar levelling layer beneath screeds thermal insulation in floors

Expanded polystyrene foam

Polystyrene (fig , C 2 , 8 e) has been used by the building industry since the 1 950s and in Ger­ many has the second-largest share of the mar­ ket. In the production of EPS, polymerisation creates EPS beads (0, 1 -2,0 mm) from the raw material styrene (obtained from petroleum or natural gas) by adding a highly volatile blowin g agent (pentane) , After drying a n d intermediate storage, the granulate is heated with steam i n pre-foam i n g units a t temperatures of approx, 1 00°C, which causes it to expand to 20-50 times its orig i nal volume before being formed i nto boards on a continuous production line, The proportion of pure recycled EPS can amount to 40% dependi n g on the application, Expanded polystyrene foam does not rot. but becomes brittle in direct sunlight (no resistance to ultraviolet radiation) and is not resistant to solvents, Owing to its comparatively high vapour d iffusion resistance, when used as i nternal i nsulation it should be ensured at the planning stage that any condensation can evaporate again, However, EPS products open to d iffusion are also available, Owing to its sen­ sitivity to temperature (max, temperature in use: 75-85°C) , this material cannot be bonded with hot bitumen or used beneath mastic asphalt. Applications thermal insulation i n almost all situations i mpact sound insulation • •

Extruded polystyrene foam (XPS)

The chemical composition of extruded polysty­ rene foam (fig , C 2 , 8 f) is almost identical to that of expanded polystyrene foam, Polystyrene granulate is melted in an extruder, foamed up by adding a blowing agent and formed into a continuous web of foam material. The blowing agent used is normally carbon dioxide these days, i nstead of the CFCs or HCFCs employed in the past. After production, all the carbon d ioxide escapes from the materi­ al and is replaced by air, XPS absorbs very little water and has a high compressive strength, It has a high diffusion resistance, but is not resistant to u ltraviolet radiation and cannot resist solvents, The maxi­ mum temperature for applications is 75°C, Applications peri pheral basement i nsulation and insulation beneath load bearing ground slabs thermal insulation to surfaces with heavy compressive loads (e,g, industrial floors, parking decks) upside-down roofs i nsulation to thermal bridges (concrete l i ntels, i nsulated starter-bar units) ·

·

·

·

•

Polyurethane foam (PUR)

•

Polyurethane foam (fig , C 2 , 8 g) achieves the best insulation values among conventional insulating material s , Its main constituents are d i phenylmethane di-isocyanate ( M D I ) , poly­ ether and/or polyester polyalcohol ; the latter

•

g C 2,7 C 2,8

C 2,8 Physical parameters of selected insul. materials Insulating materials (selection) a Glass wool b Rock wool c Cellular glass d Expanded perlite e Expanded polystyrene foam f Extruded polystyrene foam g Expanded polyurethane foam

137

I nsulating and sealing

can be produced from crude oil or renewable raw materials (e. g . sugar beet, maize, pota­ toes). Polyurethane foam is produced by mix­ ing and the chemical reactions between the l iq­ uid components when a blowin g agent such as pentane or carbon d ioxide is added. Depending on the method of production, it i s possible t o produce insulating boards without facings (slabstock foam boards), or with flexible (laminated foam boards) or rigid facings (sand­ wich panels) . Polyurethane boards laminated with aluminium on one side are vapourtight and achieve (dependi n g on product) 1--- values of 0.025 W/mK. I n situ polyurethane foam is also available in add ition to the boards. The in situ foam i s made from simi lar raw materials and is used to fi l l voids on site. Polyurethane i s not resistant to ultraviolet radia­ tion, but does not rot and, unli ke polystyrene, is resistant to both hot bitumen and solvents.

a

b

Applications insu lation over the rafters flat roofs thermal insulation to surfaces with heavy compressive loads (e. g . industrial floors, parking decks) thermal insulation beneath floating screeds sandwich panels filling of voids (in situ foam) •

•

•

c

Wood fibre insulating boards (WF)

The raw materials for the manufacture of wood fibre insulating boards (fig . C 2 . 9 b) are low­ strength wood (e.g. spruce, fir and Scots p ine) or scrap wood from sawmills. The chips are crushed, mixed with water to form a p u l p , dried to 2% residual moisture con­ tent and cut into boards. The bond is generally based on the interlocking of the fibres and the adhesive q ualities of the l i g n i n already present in the wood. Some manufacturers add small amounts of aluminium sulphate, paraffin or glue to assist the bonding process. We essentially d istinguish between porous and bitumen ised wood fibre insulating boards - the bitumen improves the moisture resistance. Wood fibre insulating boards absorb moisture, are relatively open to d iffusion, are airtight and have a high heat storage capacity. They can be recycled , and the boards without bitumen can also be composted. Applications insulation over and between rafters, also to contain loose insulating materials thermal insulation to wal l s and floors impact sound insulation •

·

·

•

•

Cork products

•

Cork insulating materials are made from the bark of the cork oak, mainly indigenous to Por­ tugal, Spain and Algeria. The first stripping is when the tree is 25-30 years old, and subse­ q uent bark removal can take place every 1 0 years without endangering the tree. Supplies of cork are therefore not unlimited and the whole process is relatively costly. We d i stinguish between various cork products depending on the method of manufacture. I n the production of insulation cork board (ICB) the bark is m i l led to form a granulate and baked under pressure in hot steam (approx. 370°C). The cork expands by 20-30% of its original volume and the resin that is released b i nds the granules into blocks (fig . C 2 . 9 c ) . Pressed cork board is produced by compact­ i n g the milled cork granulate into blocks under high pressure and subsequently sawing the blocks to form boards. I mpregnated cork con­ tains additional binder (e.g. bitumen). Granulat­ ed cork is obtained through the mechanical milling of the bark without any further additions. All cork products have relatively good thermal insulation properties and also a high heat stor­ age capacity.

Wood-wool slabs ('NW)

These consist of long wood shavings (mostly spruce). The fibres are mixed with mineral binders (magnesite or cement) , pressed together at high temperatures and subsequent­ ly dried. The chips can be pretreated with mag­ nesium sulphate to protect against insect attack. Cement-bonded boards (grey colour) absorb more water than magnesite-bonded boards (beige colour) . Wood-wool slabs have a good heat storage capacity, are open to d iffusion and can contrib­ ute to sound attenuation.

d

e

Applications permanent formwork internal fitting-out, sound-attenuating lining plaster background · ·

•

Wood-wool multi-ply boards (WW-C)

C 2.9

g C 2.9

138

Insulating materials (selection) a Wood-wool multi-ply board b Wood fibre insulating board c Insulation cork board d Cotton e Cellulose fibres f IR absorber-modified polystyrene g Vacuum insulation panel

These boards (fi g . C 2 . 9 a) consist of a core of expanded foam or mineral-fibre i nsulation and a facing of m i neral-bonded wood-wool on one side (2-ply board) or both sides (3-ply board) . The properties are the result of the respective build-up of wood-wool and i nsulation (e.g. min­ eral fibre, EPS, PUR). I n contrast to normal wood-wool slabs, wood-wool multi-ply boards comply with modern insulation standards. Applications permanent formwork insulation to the underside of roofs over base­ ments or basement parking insulation to thermal bridges (e.g. edges of floor slabs) •

Applications thermal and impact sound insulation below floating screeds or wood floor finishes insulation to l i ghtweight partitions and timber joist floors granulated cork as a loose insulating material (attenuation to voids, roofs) ·

•

•

•

•

Sheep's wool

This product comes mainly from Central Europe, but supplies from overseas (e.g . New Zealand)

Insulating a n d sealing

are also on the market. The raw wool contains about 40% grease (yolk) , foreign matter and perspiration that is removed i n the washing plant with soap and soda. Some manufacturers enhance moth protection by adding 1 -2 % by mass additions of boron salt in the order of magnitude of 1 % by mass serve as a fire retardant. After carding (disentangling and straightening) the wool, it is processed to form a thin fleece, several layers of which are nee­ dled together to form insulating mats. Fine wool - a waste product of the production process can be used for packing purposes or as back­ ing cords for joints. Sheep's wool is open to d iffusion and very hygroscopic - the fibres can absorb moisture (up to 33% by mass) and release it again with­ out impairing their insulating effect. Applications thermal insulation to (close) couple roofs insulation to l i ghtweight partitions and timber joist floors impact sound insulation packing and attenuation in voids •

·

·

·

Cotton

Cotton insulation board (fig . C 2.9 d) is pro­ duced from roughly equal parts of raw cotton and offcuts and scraps from the textiles indus­ try. Raw cotton consists of 90% cellulose, wax and pectin. The production involves cardi n g the raw mate­ rial, cleaning it mechanically and adding boron salts (pesticide, fire protection ) . Afterwards, it is processed to form a thin fleece, several layers of which are needled together to form insulat­ ing mats. This building material exhibits very good thermal and sound insulation properties. The debate continues about whether cotton - a renewable raw material - is also worthwhi l e as an insulating material from the economic view­ point. In a life cycle assessment the relatively low energy requirements of the production are offset by the long transport d istances, and the environmental effects of fertilisers and pesti­ cides are not taken into account. Some manu­ facturers use hand-picked cotton , which usual­ ly requires no pesticide, as their basic raw material .

tection) , several layers of the fleece are bond­ ed together with potato starch or by weaving in reinforci n g polyester fibres. Flax insulating materials are open to d iffusion and exhibit very good thermal and sound insulation characteris­ tics. Applications thermal insulation to floors and roofs impact sound insulation packing ·

•

•

Cellulose fibres

Among the insulating materials made from renewable raw materials, cellulose fibre prod­ ucts currently enjoy the largest market share. The raw material is scrap paper, e . g . daily newspapers printed with lead-free printing i nk, and other waste paper products. Flakes (fi g . C 2.g e) and boards made from cel­ lulose fibres d iffer with respect to methods of production and applications. In the production of cellulose flakes the scrap paper is crushed in a m ulti-stage process and mixed mechanically with boron salt (20% by mass) to improve the fire protection properties. In the production of cellulose fibreboards, rei n­ forcing fibres (jute or polyolefins) and binders (lignin sulphonate) are added after pulverising the scrap paper and mixing in the boron salt. Aluminium sulphate and tal l oil are used as waterproofing agents. Cellulose fibres exhibit very good thermal i nsu­ lation properties, are hygroscopic and open to d iffusion. The material is durable and has been used in Scandinavia and the USA since the 1 920s. However, only the processing by trained operatives in approved specialist plants guarantees non-settli n g products free from voids. For recyc l i n g , the flakes are easily col­ lected by vacuuming . Applications thermal i nsulation to (close) couple roofs and timber joist floors i nsulation to l i ghtwei g ht partitions attenuation in void s •

•

·

Innovative insulating materials

The ever more stringent thermal insulation standards and the i ncreasing thicknesses called for are currently encourag ing rapid developments and trials of highly efficient i nsu­ lating materials. Based on industrial research and development programmes, the efficiency of existing materi­ als can be constantly improved through the use of novel combinations and new effects (see "The development of innovative materials, p. 28). For examp le, adding an infrared absorber to the matrix of expanded polystyrene (fi g . C 2.9f) renders possible a reduction in thickness of up to 25% (see fig. C 2.4, p . 1 33) . The (still) comparatively high cost of such inno­ vative insulati n g materials must be weighed against the considerable gain in usable floor space and the new design options (more slender components) . For refurbishment work, high-performance insulating materials result in modern U-values even with thin assemblies ( e . g . adjacent neighbouring structures, junc­ tions around windows, short eaves overhang) . Vacuum insulation panels (VIP)

Vacuum i nsulation panels (fi g . C 2 . 9 g ) have been establ ished for use in refrigerators and deep freezes since the 1 970s, but it is only recently that the first trials and demonstrations for b u i l d i n g applications have been carried out successfully. I n comparison with conventional insulating materials, the thermal conductivity is lower by a factor of 5-1 0 . VIPs consist of a core material with a good compressive strength that is lami­ nated with gastight composite foils in a vacuum chamber. Besides fibres and open-cell foams, pyrogenic silicic acid is now the favourite filling material because - owing to its extremely small voids ( 1 00 nm) - thi s places the lowest demands on the airtightness of the envelope. The initial gas pressure is 1 -5 mbar and increases by approx. 2 mbar every year. The airtightness has a decisive influence on the durability and thermal conductivity of VIPs: · · ·

Applications thermal insulation to (close) couple roofs insulation to lightweight partitions and timber joist floors packing and attenuation in voids •

•

0.004 W/mK at < 5 mbar gas pressure 0.008 W/mK at < 1 00 mbar gas pressure 0.020 W/mK ventilated

The use of aluminium foi l or multi-layer, vacu­ um-metall ised synthetic barrier foils results in a guaranteed l ifetime of 30-50 years.

•

Flax

In Central Europe flax plants g row to a height of approx. 1 .0-1 .2 m, have a relatively short vege­ tation period and do not usually require any fer­ tilisers or pesticides. The short fibres used for flax insulating materials are a by-product of the process to obtain long fibres for the textiles industry (linen). The retted (soaked) and dried short fibres are carded and processed to form a thin fleece. After adding boron salts (fire pro-

Applications thermal insulation beneath underfloor heating internal i nsulation with faci n g of plasterboard spandrel elements for post-and-rail facades thermal insulation composite system in con­ junction with 35 mm XPS boards as plaster background (protective layer) ·

· ·

·

139

I nsulating and sealing

�

� o U)

o N

1W��,RJU Il-- 1

�

- ---

2

--

11?11I11--- 3

--

:oIIIHr--- 4

-� -� -

�

----

::ifI11r--- 5

--

-

---

6

--

.>Il/llIlr-- 7

--

1 2 --, 3

-� �

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1 2 3 4 5 6

7

Solid timber, spruce, 80 mm Softboard, 22 mm Vacuum insulation panel, 40 mm Compressible tape all round Battens, 40 x 45 mm Softboard 3-ply core plywood, 22 mm

C 2.10

Planning advice I n order to achieve U-values ,,;; 0. 1 5 W/m2K, i . e . passive-energy house standard, with conven­ tional insulating materials, a total wal l thickness > 500 mm is normal. In a pi lot project by Lichtblau Architekten, a U-value of 0. 1 4 W/m2K was achieved using a loadbearing sol id timber wal l and interchange­ able VIPs - with a total wall thickness of just 1 92 mm (fi g . C 2 . 1 0) . The thinner wal l results in a gain in usable floor space amounting to about 1 5 m2 (in relation to the total floor space of 265 m2) . The following aspects should be considered at the planning stage: •

•

•

·

Defined sizes (usually 1 .0 x 0.5 m): the panels cannot be cut, special sizes are time-consum­ ing and costly. Protection of the vacuum: the panels need a fixing without restraint, and the insulating layer must not be damaged ( e . g . nails) during construction and uti l isation of the build i n g . Thermal bridges: in comparison t o VIPs, air is a good conductor of heat; therefore joints and penetrations must be minimised . So far there is no building authority approval.

Transparent thermal insulation

Transparent thermal insulation enables the transmission heat losses through opaque exter­ nal walls to be reduced but the same time per­ mits high solar radiation transmission and, moreover, acts as a daylight element i n a trans­ lucent facade. The insulating material often makes use of cel­ lular structures (capillary, honeycomb) of glass or plastic (PM MA, PC) . Alternatively, honey­ comb structures made from recycled paper or microporous aerogel bead fillings are feasible. The insulating materials are protected against the weather, dust, dirt and mechanical damage by fitting them in the cavity of insulating glass units or between profiled glass elements or in multi-walled panels. How it works Generally, we d istinguish between three d iffer­ ent transparent thermal insulation systems:

1 40

1 2 3 4 5 6

•

•

·

-- Solar radiation

- -- Heat radiation

Glass Shading element Transparent thermal insulation Glass Absorber Masonry

---

�

a 1 2

C 2.1 1

D i rect gain system: In terms of their appearance, translucent ther­ mal insulation units integrated into post-and­ rail facades resemble acid-etched or sand­ blasted glazing (fi g . C 2 . 1 3) . The l i ght-scatter­ i n g effect of the thermal insulation structure distributes the daylight deep into the interior evenly and without g lare. In the form of triple g lazi n g with an 8 mm thick capillary panel, U-values of 0.8 W/m2K are possible. Solid wall system: The combination of transparent thermal insu­ lation elements and heat storage mass en­ ables the incident solar radiation to be con­ verted into heat at the (usual ly) b lack-painted outside face of the wal l (absorber) and trans­ ported to the i nside face of the wall after a delay (fi g . C 2 . 1 1 ) . Through the reversal of the heat flow during periods of incident solar radi­ ation, this construction realises gains of 501 50 KWh /m2 per square metre of transparent thermal insulation (depending on system, orientation, shad i n g , etc . ) . Thermally decoupled systems: Convective and hybrid systems are decoupled from the storage mass by controllable air or water layers. However, such systems are sti l l a t the development stage.

3

b Glass Panel in heating mode Masonry

1 2

3

Glass Panel in insulating mode Masonry

C 2. 1 2

converted into heat and transported to the interior via the solid masonry after a delay (fig . C 2 . 1 2) . I n insulating mode the element protects against heat losses and overheating in summer. Switching between the two modes is achieved by applying an electric current, which i nfluences the pressure relationships of the g lass-fibre core and hence alters the thermal conductivity by a factor of 40.

C 2 . 1 0 Solid timber external wall construction with inter­ changeable vacuum insulation panels C 2. 1 1 Transparent thermal insulation element with shading and temperature gradient C 2 . 1 2 Switchable thermal insulation a in heating mode (heating period and sunshine) b in insulating mode (all other times) C 2 . 1 3 "Rathausgalerien" shopping mall, Innsbruck, Austria, 2002, Dominique Perrault C 2 . 1 4 Life cycle assessment data for insulation and sealing

To protect against overheating in summer, transparent thermal insulation systems must be fitted with effective sunshades. Besi des electri­ cally driven foil roller blinds, cover plates attached manually (seasonally) are also used. Passive measures (e.g. eaves overhang , bal­ cony) can also provide some shade, but reduce the overall solar gains achievable. Switchable thermal insulation

Switchable thermal insulation is based on the knowledge gained from VIPs and transparent thermal insulation and to date only one pilot project has been completed. The facade ele­ ments can be switched as required from a highly insulating state with U-values of 0.20.3 W/m2K to a solar collector state with much higher thermal conductivity and a U-value of 1 0 W Im2K. On sunny but cold winter days (heating mode) the incident solar radiation is

C 2.13

I nsulating and sealing

Insulation Layers , for origin of data see "Life cycle assessments", p. 1 00

PEI primary energy non-renewable [MJ]

PEI primary energy renewable [MJ]

GWP global warming [kg C02 eq]

OOP ozone depletion [kg R1 1 eq]

AP acidification [kg S02eq]

EP eutrophication [kg PO. eq]

POCP summer smog [kg C2H . eq]

51 1

17

28

0

0.70

0.0062

0.022

Boards expanded polystyrene (EPS) EPS board, A = 0.040 W/mK, p = 25 kg/m3, 1 20 mm polyvinyl acetate adhesive (PVAC) extruded polystyrene (XPS)

c:::=:J 405

12

21

0

0.0049

0.50

XPS board, A = 0.040 W/mK, p = 20 kg/m3, 1 20 mm polyvinyl acetate adhesive (PVAC) polyurethane PUR

= 0.0 1 3

0.01 1

0.0060

0.00041

0.001 0

0

0.038

0.0036

0.0050

CJ

CJ

0

0. 1 3

0.0083

0.020

CJ

=

0.35

0.0 1 4

349

13

17

0

0. 1 8

15

0.24

1 .1

0

68

0.8

19

PUR board, A = 0.035 W/mK, p = 2 0 kg/m3, 1 00 mm polyvinyl acetate adhesive (PVAC) insulation cork board ICB'

0.01 6

CJ

c:=:=:J

ICB, A = 0.040 W/mK , 1 20 mm mortar-based adhesive wood-wool multi-ply board WW-C, permanent formwork'

89

V1/W-C board, A = 0.040 W/mK, p = 30 kg/m3, 1 25 mm magnesite-bonded, mineral fibres on inside

-

wood fibre insulating board WF'

436

WF board, A 0.040 W/mK, p mortar-based adhesive

1 60 k9/m3, 1 20 mm

cellular glass CG, perimeter insulation' cellular glass, A 0.040 W/mK, p bitumen compound

D

79 CJ

1 030

1 00 k9/m3, 1 20 mm

29

49

0

0

calcium silicate board

96

calcium silicate, A = 0.045 W/mK, p = 1 1 5 kg/m3, 1 40 mm mortar-based adhesive

-

3.7

c:=:=:J

16

0

c==:::::J

0.0 1 5 I

c==:::::J

0.061

0.0044

0.0030

0

c::::J

0

0.037

0.0038

0.0050

c::::J

=

0.0074

0.01 2

Fleeces mineral wool fleece

74

mineral wool lleece, )" = 0.040 W/mK, p = 20 kg/m3, 1 20 mm polyamide fixings

-

1 .4

5.4

0

=

Loose fill 2.1

perlite fill

1 87

expanded perlite, )" = 0.065 W/mK, p = 1 00 kg/m3, 1 60 m m (on ground slab)

-

cellulose fill

33

cellulose, )" = 0.040 W/mK, p = 50 kg/m3, 1 20 mm (between TJI timber beams)

•

Sealing Layers , for origin of data see "Life cycle assessments", p . 1 00

PEI primary energy non-renewable [MJ]

PEI primary energy renewable [MJ]

reaction resin waterproofing

94

3.4

epoxy mortar, 2 mm epoxy undercoat

-

plastic-modified thick bitumen coatin 9

373

11

0

0.20

I:::=J

c:==:=J

c:==::J

0

0.0 1 2

0.00074

0.0010

GWP global warming [kg C02 eq]

OOP ozone depletion [kg R 1 1 eqj

AP acidification [kg S02 eqj

EP eutrophication [kg PO. eqj

POCP summer smog [kg C2H, eqj

5.8

0

0.040

0.0029

0.0030

0

I:::=J

0

0.042

0.0044

0.0 1 5

0

c:::=:J

0

0.0030

0.00035

0

0

0.23

0.010

0.01 5

c::::::J 1 .7

1 .8 0

Spread compounds

= 1 .1

6.4

0

c==:::::J

embossed synthetic sheeting for protection (HDPE) bitumen emulsion, 3 mm mineral waterproofing

10

cement-based waterproofing, 2 mm water glass undercoat

•

0.2

0.8 0

Flexible sheeting PVC sheeting, 1 layer

31 2

PVC sheeting, 2 mm polyethylene fleece, 0.5 mm bitumen sheeting, 1 layer bitumen sheeting (G200 S4), 4 mm bitumen undercoat

35

20

=

294

5.6

I

7.4

0

I

0.091

0.0038

c::::::J

='

0.020

C 2. 1 4

1 41

I nsulating and sealing

C

Sealing

The sealing of joints or junctions between build­ ing components or their surfaces protects the building against the ingress of water, the un­ controlled loss of warm interior air through the building envelope and the ingress of cold air from the outside. Damaged or incomplete seal­ ing of joints and surfaces can lead to serious damage and increase the heating energy requirements significantly. Every b u i l ding includes a multitude of joints which compen­ sate for tolerances and enable the various components to move without restraint as they expand and contract in harmony with tempera­ ture fluctuations. In addition, joints can also be used as a means of adding texture or features to a surface, or to reflect geometrical or con­ structional configurations. Airtightness

Air can absorb water vapour up to the satura­ tion vapour pressure, i . e . until reaching the dew point, at which point the water condenses. Hot air can absorb more water vapour than cold air. As hot air cools, so its relative humidi­ ty rises. If the dew point i s reached, the water condenses within the building component (interstitial condensation). This promotes the growth of fungi (mould) , causes rotting of tim­ ber components and reduces the insulating effect of thermal insulation. Cold air that enters from outside via leaking joints can carry fibres, fungi and spores from the building compo­ nents into the interior air. These may l ead to health disorders among the occupants, gener­ ally summarised under the head i n g of "sick building syndrome". Interestingly, moisture damage to b u i l di n g components caused by condensation is mainly the result of airtig htness problems and convec­ tion, and less often water vapour d iffusion. Only approx. 1 % of the water vapour passes through the external wall as a result of the water vapour gradient between inside and out­ side. In this context it is worth noting that only proper ventilation - if necessary with controlled mechanical systems - guarantees the changes of air necessary to meet hygiene and energy economy requirements.

1 42

Blower door measurements Leaks in the b u i l d ing envelope can be estab­ lished and localised with the help of blower door measurements. In new buildings these measurements should be carried out before installing partitions and soffits, but after all win­ dows, doors, sealing layers and plastering works have been completed. One external door is temporarily removed and replaced by a special sealed fan unit which creates a (negative) pressure difference of 50 Pa between i nside and outside. Any leaks in the building envelope will cause air to be drawn into the building, which is then extracted with the fan. The measured airflow corresponds to the leakage flow (in m3/h) caused by leaks in the building envelope. Dividing this value by the vol ume of the building produces the air change rate . According to the Energy Econo­ my Act 2002, the air change rate shou ld not exceed 1 . 5/h for buildings with mechanical ventilation, and in passive-energy houses it may not exceed 0.6/h . If these values are exceeded, the leaks can be localised with special instruments. We distin­ guish between leaks in the external building components and leaks in joints around win­ dows and external doors. Leaks also impair the airborne sound insu lation. Even at the draft design stage it is important to ensure that the airtight layer is carefully planned, the aim being to provide surfaces and joints that are permanently airtight. I n doing so, it is primarily penetrations of the airtight layer, e . g . pipes and cables or loadbearing structure, that should be considered as potential weak­ nesses.

2. 1 7

Sealing of joints

Deformations of building components are caused by, for example, settlement, tempera­ ture-related changes in length or shrinkage. Poor workmanship may lead to crackin g . I n order t o keep such processes under control and to avoid damage, the effective lengths of components are limited by planned joints. I n terms of construction we distinguish between the following types of joint: Construction joints Construction joints are rigid joints. They are the result of the building process, e . g . between concrete components that cannot be poured in one operation. Construction joints always occur between foundation and walls, but the load of the walls and the continuous reinforcement is usually sufficient to seal such construction joints. However, shrinkage cracks often form at these points. A planned dummy joint simplifies the subsequent sealing of this crack because it provides space for a seal ing compound. Expansion joints Expansion joints permit the horizontal move­ ment of large building components. In order to avoid uncontrolled cracking in the structure, vertical expansion joints extend over the full height of the building, down as far as the top of the foundation, e . g . in reinforced concrete walls or a faci n g leaf of clay bricks. Expansion joints that are sealed with jointing materials to prevent ingress of rain and splash­ ing water are not waterproof in building tech­ nology terms. According to D I N 1 8 1 95 a water­ proof joint is achieved only with flexible water­ proof sheeting or a thick bitumen coatin g .

Watertightness

Planar waterproofing systems prevent the ingress of water i nto the b uild ing. Numerous materials are available for this, and these may also be combined. Besides their waterproofing characteristics, such materials should also be able to bridge over any cracks so that the sur­ face remains watertight even in the case of movement. Joint sealants complement the waterproofin g systems.

Settlement joints Different parts of the building with d ifferent total loads exert unequal vertical loads on the sub­ soil . In order to permit d ifferential settlement without restraint, settlement joints must also continue through the foundations. Separating joints Components with different physical properties, e . g . at junctions around windows, must be iso-

I nsulating and sealing

/

/

/

/

/

a

C 2. 1 8

b

lated b y separating joints that can accommo­ date temperature-related changes in length and dimensional tolerances. Such joints can also act as expansion or settlement joints at the same time. Maintenance joints These are joints exposed to severe chemical or physical influences. They must be readi l y accessible s o that they c a n be inspected regu­ larly and renewed as required. Joints without special requirements may be left open (drained joints). Other joints must be sealed . Various sealing materials can be used depending on type of joint and requirements. These materials can create any standard from draughtproof to watertight and are d ivided into the following groups: joint sealants (injectable, kneadable) waterstops sealing strips, seal i n g gaskets Joint sealants, sealing strips and sealing gas­ kets for press i n g , inserting and glueing i nto place are not suitable as the sole means of sealing i n the case of hydrostatic pressure.

b

C 2.19

Joint sealants that dry physically, e . g . butyl compounds, sol idify as the solvent or water evaporates. In the case of non-reactive joint sealants, the material does not alter after being installed. We d istinguish between plastic and elastic joint sealants depending on their defor­ mation characteristics. The permissible total deformation is max. 25%. Joint design Accord i n g to D I N 1 8 540 a joint consists of two sides, if possi ble with chamfered edges and a stable substrate. A round backing strip limits the depth of the joint and prevents the joint sealants adhering to three surfaces (fig . C 2 . 1 8) . In order to g uarantee the deforma­ bility of the joint, the backing material consists of a rot-resistant, closed-cell foam material. Only joints with a width-depth ratio of approx. 2 : 1 ( e . g . 20: 1 0 mm) wi l l remain sealed perma­ nently. The joint sealant should be pressed onto the sides of the joint to ensure adhesion. Sealants are injected from cartridges or pressed i nto place as a kneadable plastic compound. Expansion and construction joints in contact with the soil must satisfy more strin gent require­ ments, which are given in 01 N 1 8 1 95-8.

Injected joint sealants must be stable, must adhere well to the two sides of the joint (if nec­ essary in conjunction with a primer to enhance the adhesion), must withstand changing climat­ ic and mechanical loads (resi l i ence and expan­ sion behaviour), must exhi bit a non-sticky sur­ face and must be compati ble with the adjoining building materials. They should also be suitable for uneven joint surfaces. According to D I N 1 8 540 joint sealants should not be painted afterwards because the antici­ pated deformation of the sealant is usually greater than the elasticity of the paint. The out­ come is that the paint cracks and flakes off. Nevertheless, in practice sealants are often painted for aesthetic reasons.

Silicone sealants S i l i cone sealants undergo a chemically reactive curing process which exploits the moisture i n the a i r a n d produces an elastic seal . The prod­ ucts given off are acetic acid, amines or alco­ hols, depend i n g on the particular system. Sili­ cone sealants exhibit acid ic, neutral or alkal ine reactions and must be compati ble with the sub­ strate. Some products give off odours as they cure. Silicone sealants adhere very well to smooth, mineral substrates such as glass and ceram­ ics, also aluminium and coatings, both i nternal­ ly and externally. Sanitary applications, junc­ tions, terraces and balconies are the main uses. They are available in many different col­ ours.

Chemically reactive joint sealants, e . g . silicone sealants, cure due to the effects of the moisture in the air and expel molecules.

Polyurethane sealants Polyurethane sealants also undergo a chemi­ cally reactive curing process and g ive off car-

Joint sealants

C 2 . 1 5 Separating joints between precast concrete ele­ ments, office building, Munich, Germany, 2003, Amann & Gittel C 2 . 1 6 Expansion joint, separating joint C 2 . 1 7 Material and room transitions marked by joints, Museum of Modern Art, Kanazawa, Japan, 2005, Sejima Nishizawa C 2 . 1 8 Joints with sealants a expansion joint b separating joint at window-wall junction C 2 . 1 9 Thermoplastic waterstops a external b internal

bon dioxide in a viscous state. They are used for sealing basement parkin g , parking decks and waste water systems, i .e. applications that require excellent adhesive qual ities and chemi­ cal resistance. Polyurethane sealants can also be used as an elastic adhesive. MS polymer sealants This reactive sealant type adheres to many dif­ ferent substrates and unites the properties of s i licone and polyurethane sealants. It is resist­ ant to u ltraviolet radiation, is free from solvents, has no smell and can mostly be used without any pretreatment, even in the case of damp sides to the joint. Many types of paint adhere to this type of sealant, even those containing sol­ vents. Acrylate sealants Sealants based on acrylate d ispersions exhi bit a plastic d eformation behaviour. The evapora­ tion of the dispersion water causes an acrylate sealant to shrink by up to 20%. They adhere to mineral and metal substrates , also plastics. Acrylate sealants are available in many d iffer­ ent colours and are used for rigid joints (dummy joints, construction joints) . They can be covered with certain, suitable types of paint. Polysulphide sealants Two-part polysulphide sealants u ndergo a chemically reactive curing process and exhibit an elastic deformation behaviour. During the hardening process they give off highly odorous sulphur compounds. Polysulphide sealants are used for joints in external walls or as secondary seals in the manufacture of insulating g lass un its. They adhere to a number of building materials such as plaster/render, timber, syn­ thetic materials and metals. Butyl sealants These sealants are based on butyl rubber and adhere to the majority of substrates. They remain permanently sticky and are used in the form of tapes or strips, e . g . in metalworkin g . Butyl sealants containing solvents c a n be injected into joints and moisten the substrate wel l .

1 43

I nsulating and sealing

Materials for sealing joints

Sealants (injectable, kneadable) Silicone (SI)

. acidic, neutral, alkaline (products given off)

Polyurethane (PUR)

. 1 -part, 2-part

MS polymer

. 1 -part

Acrylate (AY)

· ·

1 -part, 2-part

Butyl rubber

•

with and without solvents

·

Synthetic rubber

contains solvents, dispersant

Polysulphide

Linseed oil

Waterstops

desiccant (putty)

Waterstops

Waterstops made from PVC and synthetic rub­ ber are used wherever the maximum permissi­ ble total deformation of injected sealants is exceeded or perfect adherence to the sub­ strate cannot be guaranteed. Thermoplastic and elastomeric waterstops are concreted per­ manently in place in expansion and construc­ tion joints for in situ concrete. They p rovide a waterproof barrier across the joint. We distin­ guish between internal and external waterstops (fig . C 2 . 1 9) . Alternatively, expanding gaskets can be used in construction joints. In water­ proof concrete sheet metal waterstops can be used in construction joints if little movement is anticipated. Sealing strips

Sealing strips include backing strips made from PVC for construction joints and gaskets made from synthetic rubber to exclude rain and wind. Elastic seali n g strips made from elastom­ ers or soft polyurethane foams can achieve a degree of seal ing rangi n g from draughtproof to watertight depending on the surface character-

•

elastomer waterstop with/without profile plastic, self-adhesive elastic, non-self-adhesive

Polyvinyl chloride (PVC)

·

thermoplastic waterstop

Polyethylene (PE)

·

foam backing material (gasket)

Bentonite, EPDM

·

compressible strip

Steel

·

sheet metal waterstop

CompOSite

•

compressible tube

·

foam strip soaked in acrylic resin, precompressed aluminium foil strip single-/double-sided adhesive with profile

·

gaskets

•

• ·

Silicone (SI)

Ethylene-propylene- . gaskets diene rubber(EPDM)

C 2 .20

protect against moisture from the soil, non­ hydrostatic pressure and rising damp. These sealants comprise a binder of polymer-modi­ fied cement which is mixed on site to form a slurry. The slurry is min. 2 mm thick and can bridge over small cracks.

Waterproofing

Thick bitumen coatings One- and two-part plastic-modified thick bitu­ men coatings consist of a bitumen-plastic emulsion plus a cementitious powder. It is sprayed or spread on in at least two coats. Non-rotting fleece inlays bridge over any cracks. Thick bitumen coatings protect against moisture from the soi l , a build-up of seepage water and non-hydrostatic pressure, e . g . on roof surfaces and in wet interior areas.

Horizontal and vertical waterproofing systems protect the building against moisture. Horizon­ tal damp-proof courses (dpc) between founda­ tion and wal l consisting of one or more layers of flexible bitumen sheeting prevent water rising through capillary action to saturate the wall (ris­ ing damp ) . Vertical layers of waterproofing on external walls in contact with the soil must be i nstalled according to the loadi n g cases g iven in D I N 1 8 1 95 using the specified materials. Waterproofing of building components

In D I N 1 8 1 95 parts 4-7 the waterproofing of building components against ingress of water is d ivided into the following applications:

Bituminous coatings Coatings containing bitumen are applied as hot coatings and adhesive compounds. Hot coat­ i n g s consist of straight-run or blown bitumen, often provided with fibrous or stone dust fillers, which ensure weathering and impact resist­ ance. They are used for non-hydrostatic pres­ sure applications. Adhesive compounds are used to bond flexible sheetin g to the substrate. Flexible cement-based sealants Flexible cement-based sealants can be used to

1 44

Polyurethane (PUR)

istics of the sides of the joint and the compres­ sion of the sealing strip . Sealing gaskets are fit­ ted between movable components like doors and windows, and these also contribute to sound i nsulation.

waterproofing against moisture from the soi l , e . g . ground slabs o r basement walls waterproofin g against non-hydrostatic pres­ sure, e . g . precipitation, seepage water or splashing water on roofs, floors and wal l s in wet interior areas waterproofing against external hydrostatic pressure, e.g. parts of the building below the groundwater table waterproofing against internal hydrostatic pressure, e . g . swimming pools or drinking water reservoirs

C 2.21

Sealing strips, sealing gaskets

Flexible sheeting The application of flexible sheeting made from bitumen, polymer-modified bitumen, synthetic materials and rubber is very similar to the lay­ i n g of these materials on roofs. The materials fulfil similar tasks and are described in "The building envelope" (see p p . 1 25-27) . They ensure watertightness in the case of hydrostat­ ic pressure. Embossed sheet metal is used to strengthen the waterproofing in the case of more severe loads. Waterproofing materials on components in con­ tact with the soil must be protected against mechanical damage, e . g . by external thermal insulation, drainage mats or embossed sheets. Liquid-applied waterproofing systems These systems are suitable for waterproofing, for example, roofs and basements, primarily in the case of components with complicated geometries. Liquid-applied waterproofing sys­ tems based on flexible unsaturated polyester resins, flexible PMMA and flexible polyurethane resins undergo a reactive curing process after mixing their components or through contact with moisture in the air. They are applied by spreading, rolling or sprayin g . An inlay of fleece made from synthetic fi bres serves as reinforcement and bridges over any cracks. Together, they form a composite with the sub­ strate. The thickness of the waterproofing, usu­ ally applied in two coats, must be at least

I nsulating and sealing

Materials for waterproofing

Materials for watertightness Bitumen

• • · •

•

Plastics

•

·

•

undercoat adhesive compound, coating mastic asphalt bitumen and polymer-modified bitumen flexible sheeting plastic-modified thick bitumen coating flexible synthetic sheeting (also cold-applied self-adhesive) flexible rubber sheeting (also with self-adhesive coating) liquid-applied waterproofing systems

Metal

·

embossed sheet metal

Cement

·

cement-based sealants (rigid/flexible)

1 .5 mm, or 2 mm on trafficked roof surfaces. The European Technical Approval to ETAG 005 classifies the serviceability of l i q u i d-applied roof waterproofing systems according to per­ formance. It assumes a durability of up to 25 years depending on the particular application. Liquid-applied waterproofing materials in con­ junction with tiles and flags Polymer-modified cement, waterproofing mate­ rials based on polymer dispersions and flexible reaction resins on an epoxy or polyurethane base form the waterproofing layer for a com­ posite system using tiles and flags. This com­ posite is suitable for floors and walls in kitch­ ens, sanitary areas, balconies and foodstuffs­ processing operations depend i n g on the class of use ( I - IV) . The full bond between water­ proofing layer and substrate - partly with cloth inlays to bridge over cracks - plus the overly­ ing thin bed of adhesive for the tiles or flags provides three-fold protection against leaks. Airtightness, draughtproofing

We distinguish between internal and external layers when discussi n g airtightness and draughtproofing. Some insulating materials must be protected against airflows in order to guarantee the full insulating effect. In some cir­ cumstances the sheathing in a roof construc­ tion can, for example, protect the insulation against the wind when positioned on the out­ side of the insulation and provided with over­ lapping, bonded joints. However, such layers are not airtight and the joints, fixings and junc­ tions required to achieve airtightness mean that it is generally easier to attach an airtight layer to the warm, inner side of the construction. Open to diffusion, resistant to diffusion Depending on the type of construction, vapour permeability or impermeability is required. According to DIN 41 08-3 component layers with a water vapour diffusion equivalent air layer thickness Sd $; 0.5 m are regarded as open to diffusion, layers with Sd � 1 500 m are classed as resistant to diffusion and all values in between as diffusion-retardant. The terms airtight barrier, vapour barrier and vapour check corresponded to these figures.

Materials for draughtproofing

Materials for airtightness Film/foil

. polyethylene (PE) · based on polyamide, moisture­ adaptive • polyvinyl chloride (PVC) • aluminium (AI)

Flexible sheeting

·

PE cloth-reinforced sheathing, open to diffusion

Cardboard

•

bitumen felt

Boards Paper/cardboard

•

coated, impregnated

Boards

. gypsum boards with filled joints · aluminium-laminated insulation with tongue and groove joints over rafters

• •

wood fibre insulating board (WF) foamed insulating boards

Plaster/render

Diffusion-retardant layers are used i n the majority of cases (timber construction, roofs) . Basically, the construction should become more open to d iffusion from inside to outside so that outer layers do not hamper the trans­ port of moisture. Vapour checks must be installed airtight. The reverse is also true: air­ tight barriers can be used simultaneously as a vapour check, depend i n g on the material. Installation I n the case of sol id external walls a plaster fin­ ish over the entire internal wall surface achieves adequate airtightness in most instances. In lightweight constructions airtight­ ness is guaranteed by sheetin g or boards. The weaknesses in all types of construction can be found at the joints - between d i fferent parts of the airtight layer itself and also at junctions with other components; these are often the sources of leaks. This can be avoided by ensuring min. 1 00 mm laps in the case of sheeting plus addi­ tional sealing with cloth-reinforced adhesive tape (not carpet or parcel tape! ) . Cardboard a n d paper can b e used to provide an airtight or draughtproof layer by glueing them, like wallpaper, to inner linings. Next to the rafters they can be stapled or nailed in place, provided a double welt type of joint is formed. Seal i n g strips, joint sealants and com­ pressible strips can be used to create airtight joints with other components. In add ition to sheetin g and cardboard, thermal i nSUlation systems are available with a high water vapour diffusion resistance. Used properly, neither vapour barrier nor sheathing is req uired. But their tongue and groove connections must be glued airtight.

C 2.22 C 2.20 Systematic classification of materials for sealing joints C 2.21 Installing diffusion-retardant sheeting C 2.22 Systematic classification of materials for water­ proofing C 2.23 Physical parameters of sealants C 2.24 Physical parameters of waterproofing materials

Sealant

Linseed oil putty Oil-based putty, mod. Butyl Acrylate Polyurethane Polysulphide Silicone

Type of deformation

Permissible total de­ formation [%]

Durability [a]

0 plastic plastic plastic/elastic elastic elastic elastic

,,; 2 ,,; 5 5 - 20 1 0 -25 1 0 -25 1 5 -25

generally 1 0-25 (average) 12)

C 2.23 Waterproofing material

Foil/film aluminium PE PVC polyamide

Water vapour diffusion resistance [-]

virt. vapourtight 30000 20000 not constant

Flexible sheeting polymer-mod. bit 2 2 1 500 PE-C 30 000 PVC-P 20000 60000 EPDM 250 000 PIB ECB 90 000 CSM 25 000 Coatings thick bitumen, 1 -part 2000 thick bitumen, 2-part 4000 mastic asphalt virt. vapourtight reaction resins 20000 25 cement render waterproof concrete, C45/55 1 00

Material thickness [mm]

Sd

value

[m]

" 0.05 0.25 0.25

> 1 500 1 00 30 2.8/0.2'

5 1 .2 1 .2 1 .2 1 .5 1 .5 1 .2

86 36 24 1 20 225 1 35 30

4 4 ,, 1 5 1 .5 20

8 16 > 1 500 30 0.5

200

200

, The water vapour diffusion resistance depends on the humidity of the air; the values given here are valid for 50% and 80% relative humidity. 2 Flexible sheeting type PYE-PV 200 S4 has been selected here as an example. C 2.24

1 45

Building services

C 3.1

The development of what has recently become all-embracing building services began in the second half of the 1 9th century. Although water mains and drains for towns and cities had been known since ancient times, these were built for public faci l ities (e. g . fountains in Rome) and were intended for private buildings only in exceptional circumstances. The first public drains in Germany to connect private households to the waste-water system were b u i lt in 1 856 in Hamburg. Systems for supplying drinking water came later. The first complete systems for drinking water and waste water in multi-storey buildings appeared at the beginning of the 20th century. Demands on building services grew, and so over the course of time the provision of electric­ ity, gas and other media became necessary, also heatin g , ventilation and air condition i n g . Complex b u i l d i n g services installations with computer control have been available since the early 1 980s.

To do this, primary horizontal and vertical runs are grouped in d ucts and shafts respectively. Energy-savin g operation demands short runs, particu larly in the case of heating and hot-water pipes. The advantage of services installed in shafts or behind false walls - instead of being built in or cast in - is that they can be replaced and repaired without damaging walls, floors and other elements. D uring refurbishment or demolition work, serv­ ices in shafts or behind false wal l s can be d is­ mantled, removed , sorted and recycled. The followin g criteria are important when selecting materials or types of installation: ·

•

• • ·

Principles

C 3.1 C 3.2 C 3.3 C 3.4

1 46

Inmos microprocessor factory, Newport, UK, 1 987, Richard Rogers Applications for materials for drinking water sys­ tems Applications for materials for building drainage and waste-water systems Applications for materials for heating systems

In a detached house with masonry walls, 1 20 m2 of usable floor space and a standard level of comfort, the building services for water, waste water, heating and electricity add up to approx. 2.5% of the total mass of the build i n g . Even in laboratories and hospitals, with a high level of building services, this figure does not exceed 6%. Consequently, the potential for saving materials is only low in the case of building services. However, their influence on capital outlay and running costs is high. Furthermore, the integra­ tion of building services leads to d ifficulties in terms of disposal and recycling. Well organised and accurate planning of building services sys­ tems is therefore vital - the most economical instal lation is the one that is made superfluous by sound planning and desig n . A s building services are subject t o a shorter replacement cycle than load bearing compo­ nents, they should be designed in a way com­ mensurate with chan g i n g demands and easy replaceability.

• • • • • • ·

chemical and physical influences of the medi­ um being conveyed chemical and physical i nfluences of the ambient conditions susceptibil ity to furring maintenance options potential environmental or health impacts of the material during manufacture, usage and disposal adaptability to new user demands sound i nsulation, fire protection costs type of installation time required for installation l ife cycle assessment of materials aesthetic req u i rements

Only water, waste water, heating, ventilation, air conditioning and electrical installations are considered in the followin g . The other special areas of building services, e . g . escalators and lifts, waste disposal systems, special require­ ments for special buildings (e. g . hospitals) , are not considered in this book.

Building services

Drinking water systems

Drinking water is vital to l ife. All components that come into contact with drinking water must therefore comply with EU legislation, which requires that the drinking water must remain completely unaffected . This applies from the waterworks to the public and private water mains to the drinking water draw-off points. All materials and fittings (connectors, valves, etc.) for the systems must be approved for a continuous pressure of approx. 5 bar from the public water main and for peak pressures of max. 1 0 bar (Pn 1 0) . There are two principal factors that influence the suitability and durabil­ ity of a material for drinking water systems: hardness and pH value. The hardness of the water describes the content of magnesium car­ bonate and calcium carbonate (lime) in the water. The higher this content (i.e. the harder the water) , the more susceptible the system is to furring (incrustation), which can lead to pres­ sure losses, even blockages in the p i pes. With a neutral pH value of 7, there are no restrictions on material. But any marked deviations from this neutral value lead to an increased reac­ tivity of the water, which can have a damag i n g , usually corrosive, effect o n the material o f the pipe. The pH values permitted for drinking water according to European legislation lie between 6.5 and 9.5. Further factors are given in fig. 3.2.

extremely resistant to corrosion regardless of the composition of the drinking water. Stainless steel has no effect on the taste and does not affect the drinking water in any way. These pipes are very long-lasting and can also be recycled. When laying in the soil, stainless steel p ipes should be protected against external cor­ rosion. Copper pipes Accord ing to the provisions of Germany's cur­ rent Drinking Water Act (TwVO 2001 ) , copper p ipes are only approved for drinking water sys­ tems with a pH value > 7.4. I n the case of val­ ues > 7.0, the concentration of organic carbon in the drinking water (TOC value) may not exceed 1 .5 m g l l . If h igher concentrations of hydrogen ions occur in the water, copper can dissolve into the water and cause high concen­ trations in humans. As the water supply companies cannot guaran­ tee a consistent drinking water q uality (in terms of the pH value) over the lifetime of a b u i l d i n g 's water system , the use of copper p i pes for drinking water suppl ies is no longer recom­ mended. In the case of existin g copper pipe­ work, it may prove necessary to install a water treatment plant within the building in order to regulate the pH value and avoid any health hazards. Copper is a valuable raw material that can be recycled without any problems. Its straightforward , low-cost installation is a further advantage.

Metal pipes

Metal pipes achieve good durabi l ity. Despite their thin walls, they are very stable and can withstand some mechan ical damage, which simplifies installation. However, their vulnerabil­ ity to corrosion may need to be taken into account depending on the particular conditions. When adding metal p ipes to an existin g sys­ tem, it is essential to ensure that the metal matches that of the existing pipes, or to use a non-metal material because otherwise owing to the different electrochemical potentials of dif­ ferent metals, galvanic corrosion could occur. Galvanised steel pipes Steel pipes - seamless or welded - are galva­ nised inside and outside. As cadmium and zinc can dissolve out of the galvanic coating, such pipes should be used for service temperatures of max. 60°C only in order to avoid an unac­ ceptable concentration of metal ions in the drinking water. Galvanised steel p i pes are suit­ able for drinking water with a neutral to slightly alkaline pH value only; an acidic environment accelerates the dissolution of the zinc coating. Installed properly, galvanised steel pipes are very durable, provided the anti-corrosion coat­ ing is not damaged. But the high cost of instal­ lation restricts the use of these pipes consider­ ably. Stainless steel pipes Like galvanised steel p i pes, stainless steel pipes can be seamless or welded . They are

Lead pipes Lead pipes have been banned for new pipe­ work installations for many decades. In the light of the health hazards, the removal of all lead pipes must be considered as an urgent priority. Plastic pipes

Owin g to their low weight, plastic p i pes are easy to work and insta l l , but must be fixed to the structure at closer intervals than metal p i pes because they are less rigid. They are not electrically conductive and are therefore not suscepti ble to stray currents The smooth surface of plastic pipes makes them less vulnerable to furring within the cross­ section. They have a low flow resistance and cause l ittle noise. They are resistant to chemi­ cals and can be used for drinking water with any pH value. Non-toxicity and minimal influ­ ence on the quality of the water represent fur­ ther advantages. However, plastic p i pes are more vulnerable to mechanical damage than metal pipes and become brittle at low temperatures. Another disadvantage is their considerable thermal expansion, which calls for an appropriate installation in order to avoid irritating noises as the pipes expand and contract. Plastic pipes with plain ends can be glued or welded together. However, this i nvolves health hazards due to the substances used or the vapours given off when the plastic melts. Mechanical fittings (screw or compression

joints) are therefore available and have become well establ ished, also thanks to their d urab i l ity and reliability. As plastics can form ideal habitats for colonies of bacteria, germicidal metal salts are added to some drinking water p i pe materials. There is so far no evidence that such salts influence the quality of the drinking water. Untreated pipes must be i mpermeable to light and must be laid concealed in order to avoid attractin g bacteria. Plastic pipes belong to building materials class B (combustible) . They are less durable than metal pipes, but must last at least 50 years in order to obtain building authority approval. Pipes of high-density polyethylene (PE-HO) H i gh-density polyethylene can be used for cold-water pipework only, and therefore is mainly used for public water mains laid in the soi l and for the supply pipes to buildings. PE­ HO pipes are easy to work. The oxygen in drinking water (average content 3 g /l) can break down the molecular chains of the polymer under certain conditions. This can be prevented by adding an anti-oxidant (e.g. polynuclear phenols). The material's resistance to ultraviolet light can be i mproved by adding carbon black, which also dyes the material black. Pipes of cross-linked polyethylene (PE-X) The properties of cross-linked polyethylene are better than those of other polyethylene materials. Cross-linked polyethylene has an enhanced impact resistance and better permissible bend­ i n g , tensile and compressive strengths. As the long-time creep rupture strength of this material is also hig her, it is used for p ipes that must sat­ isfy particularly demanding bending require­ ments. PE-X is thermally stable and can be used for hot- or cold-water systems. Polyethylene p i pes are also available as p ipe­ in-pipe systems. Here, the p i pe (PE-X) carrying the water is installed in a corrugated protective pipe made from PE-HO, which can be supplied fully insulated for hot-water l ines. Pipes of polyvinyl chloride (PVC) PVC is a highly advanced synthetic material with almost ideal technical properties, but is sti ll problematic from the ecological and fire viewpoints. This plastic is mainly used in the form of post-chlorinated PVC-C when required for drinking water pipes. The material is stable up to 1 00°C and therefore may be used for both cold- and hot-water p i pes. U nplasticised PVC (PVC-U) contains no plasticisers. It is suit­ able for temperatures of max. 45°C and is therefore used for waste water only. Pipes of polypropylene (PP) I n pipework polypropylene is mainly used in the form of random copolymer PP-R. The proper­ ties of this material are very similar to those of polyethylene, but PP-R can withstand higher temperatures and is therefore also suitable for hot-water systems. It is harder than polyethy-

1 47

Building services

nected with fittings made from metal, PPSU or PVDF.

polishing, electroplatin g (e.g. chromium) or powder coatin g .

Composite pipes

Fittings

These are mUlti-layer p i pes whose layers are permanently bonded together. The inner l i n i n g carrying t h e water c a n be made from various plastics (PE-HD, PE-X, PB, PP) . This lining is embedded in a stabilising, welded aluminium pipe which is i n turn encased in a protective layer of plastic (PE-X, PB, PP) . Such p ipes unite the advantages of plastic and metal p ipes. The plastic inside and outside is not vulnerable to corrosion or furring and is resistant to chemi­ cals. Aluminium is resistant to diffusion and ensures good d imensional stability and low thermal expansion. Such pipes are low i n weight and easy to install because they are very stable but at the same time flexible.

Valves, meters etc. for water consist mainly of metal parts. However, plastics such as PP are often used for some of the mechanical parts inside, plus seals made from EPDM etc. The quantity of these materials is so low that it has no noticeable influence on the qual ity of the drinking water. Ceramics are being used and more and more for the seals in fittings because ceramics do not affect the drinking water in any way and are more d urable than synthetic mate­ rials.

Gunmetal fittings Like brass, gunmetal is an alloy of copper, tin (max. 1 1 %), zinc (max. 9%) , lead (max. 7%) and nickel (max. 2 .5%) . Gunmetal components can produced by casting only. They therefore have a rough surface, possibly exhibiting seg­ regation, shrinkage and pores. Such defects can lead to fai lures in the case of mechanical load i n g , excessive noise and leaks. Gunmetal is primarily used for larger fittings. Gunmetal and brass can be installed with metal pipes without fear of galvanic corrosion. These valuable alloys are readily recycled .

lene and is primarily used for supply p i pes and d istribution pipework.

Joint fittings for plastic pipes

The connectors for plastic pipes can be made from metal, PP-R, PVC-C, polysulphone (PPSU) or polyvinylidene fluoride (PVDF) . Generally, pipes of PP-R, PB and PVC-C require cou­ plings made from the same material as the pipe. PE-X and composite pipes can be con. I s for d ron ' k·ong Materoa water systems

Abbrevlatlon

Brass fittings Brass is suitable for high mechan ical loads and may be used (according to the 2001 Drinking Water Act) for drinking water fittings provided it contains no more than 3% lead in add ition to copper and zinc. Pressed or forged compo­ nents are better than cast ones because of their dense, homogeneous structure. The surfaces of brass components can be ground very smooth, which reduces flow resist­ ance and noise, and also permits further

App r1cations

nsta 11 atlon . in ...

Technical rules

Cl C

D 0 u

E

6


'Q ·s .D

ype 0f Joont ' · 2



D

Chromium plating Fittings, joints, etc. can be given a plating of chromium, especially if they are to remain visible. Chromium plating provides excellent protection

p H -range

Welg · ht d-20mm

C oeffIClent · of thermal expansion

D ura b-

[-]

[kg/m]

[mm/mK]

[a]

6.5-9.5

0.7

0.01 1 8

80-100

·

A1

. .

7.0-8.0

1 .5

0.01 1 8

40-60

·

A1

.

>

0.59

0.01 66

40-60

·

A1

6.5-9.5

0.33

0.07-0.08

70-90

0

81

m

-'" u c o .Q

Stainless steel fittings Fittings in sanitary areas can also be manufac­ tured from stainless steel; but due to the costly machining processes, they are more expensive than fittings made from copper-zinc alloys.

ility '

R ecyclab- Building ility materials class 9

D

�Q) � � �u E :Q D Q) � -t � g �

Metals stainless steel DIN 2463; DVGW W 54 1 ; DIN EN ISO 1 1 27; DIN 1 7 455; DIN 1 7456 steel, hot-dip galvanised 3. 4 DIN 2440; DIN 244 1 ; DIN 2460; DIN EN 1 0 255; DIN EN 1 0 240; DIN EN 1 0 220 copper D I N EN 1 057; DVGW GW 392; DVGW W 544

V2A!V4A

·

·

.'

·

·

·

Fe (Zn)

·

·

.'

·

·

.5

Cu

·

·

·

·

·

PVC-C

·

·

·

PE-X

·

·

·

PE-HO

·

PP

·

·

·

·

•

·

7.4

6

Plastics post-chlorinated polyvinyl chloride DIN 8079; DIN 8080 cross-linked polyethylene DIN 1 6 892; DIN 1 6893; DVGW W 544 unplasticised polyethylene D I N 1 9 533; DIN 8074; D I N 8075; DVGW W 320 polypropylene DIN 8077; D I N 8078; DVGW W 544; DIN 8078; DVGW W 544

.

·

.

·

·

·

·

·

·

·

·

·

·

·

·

·

·

6.5-9.5

0.25

0.2

70-90

0

82 •

·

·

6.5-9.5

0. 1 7

0.2

40-60

0

82 •

·

6.5-9.5

0.45

0. 1 2

60-80

0

82 •

6.5-9.5

0.2-0.5

0.025-0.03

40-60

-

82 •

Composites composite pipe DVGW W 542

PE-X/AI/PE-X PE-HD/AII PE-X/PP I AIIPP

·

·

, Only with additional anti-corrosion coating. On plastic pipes screw, compression and clamped connections are carried out with special fittin9s to DVGW W 534. 3 Zinc coatin9 to D I N 50930-6; possibly also with additional anti-corrosion coatings of bitumen or synthetic materials to D I N 2445. 4 Do not install downstream of copper components. 5 Pipe threads must comply with D I N 2999-1 . 6 May only be used with pH value � 7.4, or for pH value 7.0-7.4 and TOC value ,; 1 .5 mg/l. ' The durability of pipework depends less on the material and far more on the workmanship during installation. · Class 81 (not readily flammable) can only be achieved with a flame retardant. 9 Owing to the still inadequate testing guidelines for pipework to DIN EN 1 3501 - 1 , the D I N 4 1 02 classification is still used. 2

1 48

C 3.2

Building services

against corrosion . However, the unavoidable polishing and cleaning of chromium-plated fit­ tings can have an impact on the environment in the form of a fine dust i n the atmosphere or waste water.

mainly used externally, in the ground (building drains, sewer connections) because within buildings their weight and vulnerability to dam­ age make them difficult to lay. They are mainly supplied in the form of spigot­ and-socket p i pes with l i p seals, O-rings or D­ rings made from elastomers. However, they can also be supplied with plain ends (no sock­ ets) and joined using sleeve couplings with an elastomer inlay. Stoneware pipes are very long­ lastin g . I n the form of perforated pipes, they are also used as field drains i n subsoil drainage schemes. Neither the production nor the use of these pi pes result in any health or environmental haz­ ards. They can be crushed and recycled as fill material.

Waste-water systems

Waste-water pipes must be suitable for a water temperature of max. 95°C when laid within buildings or max. 45°C when laid in the ground, and must remain permanently gastight and watertight at an overpressure of 0.5 bar. The internal walls of the pipes plus the joints and transitions should not promote deposits, furring and clogging. Although plastic pipes are easier to lay owing to their low weight, the poor sound insulation of such pipes must be considered when laying them inside buildings.

Technical rules

Abbreviation

Applications waste-water pipes ID a.

'0.

ID C) c .� 0. a. co

Ceramics stoneware

Steel and stainless steel pipes Galvanised steel pipes can be used for all types of waste-water system. They are protected against corrosion inside and outside by hot-dip galvanising plus a synthetic resin coating inside. Their relatively thin walls (approx. 2 mm) and sockets make them easier to lay than compara­ ble cast iron pipes. Additional corrosion protec­ tion is req uired when laying them in the soil. Stai nless steel pipes are only used for very aggressive waste water and special applica­ tions (e.g. med ical and industrial) .

Cast iron pipes Ductile cast iron is preferred for p i pes because its production leads to a more stable, more flexible and also more corrosion-resistant prod­ uct than the grey cast iron used in the past. Normally supplied in the form of spigot-and­ socket pi pes, they can also be obtained with plain ends for laying with cou p l i n g sleeves. The seals are made from EPDM, chloroprene rub-

Stoneware pipes Stoneware pipes are ceramic products which are g lazed on the inside and usually on the out­ side as wel l . This surface treatment makes them extremely resistant to all the constituents found in waste water. Stoneware pipes are

Materials for waste-water systems

ber (CR) or other elastomers depending on the type of waste water expected. Cast iron p i pes are used both inside the build­ ing and underground. The i nner walls are smoothed in order to prevent furri n g . They are resistant to boiling water, impacts and abra­ sion, are d i mensionally stable and incombusti­ ble. Depending on the requirements regarding chemicals resistance, the p i pes can be given a coatin g of plastic (e.g. PUR) or zinc on the inside or outside. The decoupling of the struc­ ture-borne sound at all seals and their high self-weight gives them good sound insulation properties, but their installation is costly.

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DIN 1 230; DIN EN 295 Metals ductile cast iron

DIN 1 9 522 steel, hot-dip galvanised Fe DIN 1 9 530; D I N 2440; D I N 2448 zinc sheet Zn D I N 1 8 461 ; D I N EN 6 1 2 copper sheet Cu D I N 1 8 461 ; D I N EN 6 1 2 Fe (ZN) steel sheet, hot-d ip galvanised DIN 1 8 461 ; DIN EN 61 2; D I N 2440; D I N 2458 aluminium sheet AI DIN 1 8 461 ; DIN EN 6 1 2 Plastics unplasticised polyvinyl chloride DIN V 1 9 534 post-chlorinated polyvinyl chloride DIN 1 9 538 un plasticised polyethylene DIN 1 9 535 D I N 1 9 537 polypropylene DIN V 1 9 560

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' Only with thin walls and plain ends. 2 0nly with additional anti-corrosion coating. ' Class 81 (not readily flammable) can only be achieved with a flame retardant. 4 Owing to the still inadequate testing guidelines for pipework to DIN EN 1 3501 -1 , the DIN 4 1 02 classification is still used. 'The durability of pipework depends less on the material and far more on the workmanship during installation.

.

C 3.3

1 49

Building services

Pipes of polypropylene (PP) Owing to their high chemical resistance, poly­ propylene pipes are very popular for waste­ water applications. The pipes are manufac­ tured with a socket at one end fitted with O-ring or double lip EPDM seal . Pipes o f polyethylene (PE- HO) High-density polyethylene pipes are used both within buildings and also undergroun d . They are similar to the socketed pipes made from polypropylene. However, they can also be sup­ plied with p lain ends for butt welding. Pipes of unplasticised polyvinyl chloride (PVC-U) Owing to the low heat resistance of this materi­ al (max. 45°C) , pipes of PVC-U are used almost exclusively for underground drains. They are mainly used in the form of spigot-and-socket pipes like the polypropylene pipes. However, systems with glued sleeve couplings are also available for use i nside buildings.

um conveyed are no longer relevant because heating systems do not convey drinking water. Depend ing on the heating system adopted, the materials must resist temperatures of up to 1 1 aoc. Like drinking water l ines, all pipes, joints and fittings must withstand a test pres­ sure of 1 a bar. As the heating system forms a closed circuit and there is no regular exchange of water, internal corrosion of the pipes and radiators represents only a minor problem. The oxygen in solution in the hot water, which is the main cause of corrosion, becomes bonded after a short period of operation and can no longer attack the material. Furthermore, an alkal ine pH value is recommended for the hot water in order to minimise the corrosion. If plastic pipes are used for the heating system , these should be impervious to oxygen d iffusion because oth­ erwise oxygen can seep through and initiate a corrosion process on metal parts. Steel pipes (black

Sanitary appliances

Wash-basins, toilets and baths are the primary fixtures in sanitary areas. The choice of material is therefore mainly governed by appearance criteria. Nevertheless, material qual ities such as susceptibility to scratches and impacts, sur­ face finish, ease of cleaning and durability should also be considered when choosing the appliances. The majority of sanitary appliances are made from ceramics. A g laze finish improves appear­ ance and durabi lity; but ceramic appliances are vulnerable to damage. Sanitary appliances produced from cold­ formed sheet steel are usually given an enamel finish to protect them from corrosion . The sur­ face finish is very hardwearing and durable, but the steel will beg in to rust as soon as the enamel is damaged. Stainless steel sanitary appl iances are corro­ sion-resistant and very hardwearin g . They are used in extreme conditions where scratches and impacts (vandalism) cannot be ruled out. Synthetic materials are used for sanitary appli­ ances in the form of coloured PMMA. This material is relatively impact-resistant, but the surface is vulnerable to scratches. Thanks to its low thermal conductivity, the surface feels warm to the touch, in contrast to ceramics or steel. Owing to its brittleness, g lass is a sensitive material, but its surface is very hardwearing and easy to clean. In sanitary areas g lass is primarily used in the form of toughened safety glass for shower cabins, but also for wash­ basins.

=

non-galvanised)

Unprotected steel in the form of welded or seamless p i pes can be used for heating sys­ tems. This is an i nexpensive solution and these pipes can achieve service lives simi lar to other piping materials. Steel pipes are used mainly for larger pipe d iameters, with welded joints. If galvanised steel pipes are used, these should be joined with sockets (see p. 1 47).

In principle, heating systems can use all the materials that are also suitable for hot-water installations. However, the requirements regard ing maintaining the qual ity of the medi-

1 50

Like hot-water pi pes, heating pipes, too, must be i nsulated in order to prevent heat losses. Prefabricated shells of, for example, polyisocy­ anurate, polyurethane, polyethylene, polysty­ rene or rubber are available for this purpose, in sizes to match the outside diameter of the pipes. Mineral-fibre insulating materials are particularly suitable in the case of more severe fire protection requirements. As a rule, the shells have a plastic or metal covering, e . g . PVC , PP, P E , aluminium foil/sheet, o r galva­ nised steel sheet.

Ventilation and air conditioning

Pi pes for ventilation systems must be airtight, depend ing on the operating pressure of the system, in order to prevent pressure losses during distribution and to be able to convey the air to the places where it is required. In order to rule out any health hazards, the materials used may not release any gaseous, liquid or solid substances i nto the air being conveyed . The internal surfaces should prevent deposits of dust as far as possible. Fire protection is espe­ cially important for the design and choice of materials where p i pes and ducts penetrate fire walls. Sheet steel ducts

Copper pipes

Copper is the favourite material for heating p i pes. Its flexi bility makes it quick and easy to insta l l . The p i pes can be soldered together or joined with special compression fittings. Cop­ per is resistant to damage and can also be supplied ex works with a protective PVC sleeve, or insulatin g materia l . I n the latter case only the connections have to be insulated on site. Plastic ducts

Owing to their thermal stability, polybutene (PB) , polypropylene (PP-R) and cross-l inked polyethylene (PE-X) are the synthetic materials suitable for heating systems. But their consider­ able thermal expansion must be taken into account during i nstallation. As PB and PP-R are permeable to oxygen, a decision must be taken as to whether these materials can be permitted at all. If concealed heating coils embedded in the walls and floors are in use, which can also use plastic pipes, then corrosion problems will not occur. Howev­ er, in this case all the other parts of the system (boiler, tank, valves, etc. ) must also be corro­ sion-resistant. Composite pipes

Heating systems

Pipe insulation (lagging)

The advantages of composite pi pes g iven i n the section o n drinking water are especial ly rel­ evant for heating systems. The aluminium jack­ et makes the pipes oxygen-tight and they have a lower thermal expansion than pipes made solely of plastic.

Galvanised steel sheet has a smooth surface, resists corrosion and is easy to clean. It is incombusti ble, but does not offer any fire resist­ ance. Ventilation ducts made from sheet steel are available with round (spiral-welded), square/rectangular or flat oval cross-sections. In order to prevent resonance and noise, the side panels of ventilation ducts are stabi lised by g iving them an outward bow which forms a shal low pyramid. I n special cases in which large quantities of aggressive exhaust-air are antici pated, sheet stainless steel or aluminium can be used as an alternative. Plastic ducts

Synthetic materials such as PVC, PE and PP are combustible and therefore can be used i n smaller buildings only, or within a fire compart­ ment. These materials are highly resistant to aggressive gases and vapours, but are rela­ tively expensive and are available for smaller duct cross-sections only. Besides steel and plastics, in special instances concrete or masonry are also used for large duct cross-sections over longer distances, or stoneware pipes and g lass for special applica­ tions such as laboratory extracts. Flexible pipes or hoses made from glass fibre, plastics, aluminium or elastomers are the usual choice for providing variable connections to air outlets in ducts with a large cross-section . Such pipes/hoses can compensate for building toler­ ances, but owing to their materials and quali­ ties are not suitable for penetrating fire walls.

Building services

and ethylene vinyl acetate, EVAC) , natural or synthetic rubber (e.g. EPOM) or silicone rubber can be used as an alternative to PVC insula­ tion. However, these alternatives are flamma­ ble, which represents another fire risk. I nstead of flame retardants containing halogen, the addition of mineral fillers can help here, but these reduce the flexibil ity and bendability of the cables.

Electrical installations Electric cables

Electric cables provide the power and Iow-volt­ age distribution systems within a building. The metallic conductor, usually copper, is encased in insulation plus sheathing. The insulation must g uarantee permanent protection to the current­ carrying conductor in order to prevent injuries to persons and damage to property caused by electric shock or fire. A uniform designation system for power cables has been introduced within the scope of Euro­ pean standard isation. The designation incl udes the insulation and sheathing materials. I nsulation and sheathing are genera l ly made from plasticised PVC because it exhibits excel­ lent properties with regard to function, d urabili­ ty and ease of workin g . Owing to its high chlo­ rinated halogens content, PVC is classed as flame-retardant and is assigned to building materials class B 1 . The disadvantages of this material are the fumes off during a fire plus the production and disposal problems. Various non-halogen plastics (PP, PE-LO, PE-X

Materials for h eating systems

Abb revlatlon

Protective conduits and cable ducts

Surface-mounted electric cables may require protective conduits and/or cable ducts, which are usually made from PVC. The alternatives are other p lastics such as PE-H O, but also sheet steel ( galvanised, painted) , stain less steel or aluminium. Switches a n d sockets

The operating elements for electrical installa­ tions are made from galvanised steel sheet with insulatin g parts of various hard plastics. Cover and fascia plates are mainly manufactured from coloured or coated ABS plastic, but g lass or metal may also be used.

App Icatlons

Technical rules

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1 On plastic pipes screw, compression and clamped connections are carried out with special fittings to DVGW w 534. ' Virtually impermeable to oxygen. 3 According to DVGW test with 70°C and 1 0 bar, continuous operation; the durability of pipework depends less on the material and far more on the workmanship during installation. Lower temperatures and pressures increase the durability. 4 Owing to the still inadequate testing guidelines for pi pework to DIN EN 1 3501 -1 , the DIN 4 1 02 classification is still used. 5 Class B1 (not readily flammable) can only be achieved with a flame retardant. C 3.4

1 51

Walls

C 4. 1

Walls define spaces, rooms. And in the German language there is a d ifferentiation between classes of wall: " . . . between die Wand, indicat­ ing a screen-like partition such as we find i n wattle a n d daub infi l l construction, a n d die Mauer, signifying massive fortification" (Kenneth Frampton: Studies in Tectonic Culture) . Fig. C 4.2 shows the principal wall construction options. Categories We divide walls into loadbearing, bracing and non-load bearing constructions. Ring beams, capping beams, upstand beams and down­ stand beams can all form integral parts of walls to accommodate the forces from roof or floor constructions. ·

•

•

A load bearing wall is one that transfers more load to the foundations than just its self­ weight. A bracing wal l - often called a shear wall - is one that withstands actions due to wind loads, horizontal impact loads, etc. A non-load bearing wall - often called a partiti­ on - is one that subd ivides the interior space according to function and utilisation and does not form part of the load bearing structure.

Two d isparate concepts dominate architecture with regard to the construction of walls: on the one han d , the construction of a sol i d wall of masonry, i .e. the geometric layering of (small­ format) elements (which Gottfried Semper calls

Wall of 1 3 000 coloured oil drums, 26 m high x 68 m wide, gasometer, Oberhausen, Germany, 1 999, Christo & Jeanne-Claude C 4.2 Wall construction principles irrespective of material: a homogeneous wall b masonry wall c frame d wall of linear elementsllayers e wall claddingllining f sandwich construction g studding C 4.3 Systematic classification of methods of construc­ tion and materials for walls

"stereotomy") , and , o n the other, the creation of a boundary by infilling a construction (Semper's "tectonics"). This d istinction does not take i nto account industrialised forms of construction, e . g . reinforced concrete or various modular systems. According to the current state of the art, walls can be classified according to the following subgroups (fi g . C 4.3) : •

Sol i d construction - solid homogeneous walls - solid modular walls - solid l i near forms

•

Modular construction - small-format systems - large-format systems

·

Frame construction - single-layer walls - mu lti-layer walls

Requirements and properties of walls Many aspects must be considered when selecting a type of wall construction and the materials. The prime design consideration con­ cerns the boundary of the room, the interior space, and the stipulation of openings for access, l ight and air. Walls can be opaque, translucent or transparent. The geometry deter­ mines the distribution of the loads (individual, concentrated , linear) and the required com-

C 4.1

a

b

c

d

e

g C 4.2

1 52

Walls

Solid construction

stone loam

tamped loam

ceramic materials mineral materials gypsum concrete

I

stone I I I loam bricks etc. I clay bricks kalc. silicate bricksl wall panels

in situ concrete

Modular construction

I 1 1tw!. concr. bricks I

stone cladding

insul. clay bricks

Igypsum wallboardsl

timber

log construction

metal glass

glass bricks

Frame construction

II

profiled glass

I

loam boards

I I clay brick panels I I aer. conc. elem. I

I concrete systems I lprefabricated wallsl timber systems I panel construction I Isandwich elementsI panels

perlite boards plasterboards

I fibre-cement sht. I I I wood-based bds. I I sheet metal etc.

'- -----------' ti m be r fra m e steel frame

post-and-rail C 4.3

pressive strength of the materials. Any static or dynamic deformations of other components such as intermediate floors or foundations, like­ wise seismic effects, may also influence the choice of materials. Furthermore, building serv­ ices may need to be integrated into the wall. Materials and forms of construction should ena­ ble the incorporation and, wherever possible, the replacement of the relatively short-lived services components. In addition to the planned uti l isation, the wall will have to satisfy building performance parameters, e . g . sound insulation, thermal i nsu­ lation, absorption capacity, vapour permeabil ity or fire resistance. Safety and/or security con­ siderations could influence the construction of a wall, hygiene specifications the design of the wall surfaces. The construction process itself could also place further conditions on the choice of materials. The maximum self-weight and the dimensions influence the production and the transportation of the wal l elements, which in turn have an influence on construction time and costs. Planning strategies In order to satisfy the complex req u i rements placed on a wal l , we can choose one of two basic approaches: I n the additive approach, specific layers of materials, each of which fulfils one or more specific tasks, complement each other and together provide all the desired properties. The focus here is on proper detai ling of junctions and joints. If the wall has a covering (cladding/ lining ) , this results in independent architectural options for the wall surfaces in terms of junc­ tions, surface texture and surface finish. Contrastingly, in the integrated approach, the details and joints are, in the ideal case, simpli­ fied by the efficiency of one material that fulfils all the requirements. The emphasis here is on the careful selection of a suitable material. Exposed constructional components always place high demands on the planning: pattern of joints, building services, i ntegral elements, etc. must all be considered right from the start.

Solid homogeneous walls

The construction of walls in situ made from a mouldable material offers numerous advantag­ es - besides the design freedom regarding shapes and dimensions, primarily the ease of hand l i n g and the ready adaptation of the wall thickness to meet structural and other require­ ments. Suitable materials are concrete and tamped loam. In such cases, the wall i s given its shape by placing the material in a mould, the formwork, which is removed (struck) once the material has hardened or dried. The form­ work is a temporary facility erected for this pur­ pose only. However, if the formwork remains behind as part of the structure, we speak of permanent formwork. Solid homogeneous walls usually exhibit a high strength and therefore are ideal as load bearing components and are rarely used solely as par­ titions. Tamped loam walls

Due to the construction process, tamped loam walls are usually thicker (generally � 400 mm) than walls made from other building materials. The thermal conductivity and heat storage capacity of tamped loam are roughly equal to clay bricks of the same density. The irregulari­ ties of the production process, e . g . course heights (lifts) or changes to the material com­ position, remain visible on the finished surfac­ es. Adding relief to the surfaces can i ncrease the haptic and visual i nterest (fig . C 4.4) . Fair-face concrete walls

Concrete is regarded as an expensive building material, but concrete walls nevertheless require extensive, costly formwork. There are therefore a number of strategies that can be employed to simplify the construction of con­ crete walls. The Romans cast their concrete between clay brickwork - a form of permanent formwork that served as the finished surfaces. The timber formwork used frequently these days must satisfy several building technology requirements: the ability of the formwork to resist the pressure of the wet concrete fi l l i n g determines the maximum height o f a so-called lift, the formwork also restricts the space for

placing and compacting the concrete. Howev­ er, a high number of reuses - ensured through repetition of elements and surfaces - can help to offset the high cost of formwork. This i s par­ ticularly true for steel forms, which are also suit­ able for producing large numbers of precast elements. The mouldability of reinforced con­ crete during the concreting process enables the wal l to be assigned further functions. Con­ crete walls may be load bearing or non-Ioad­ bearin g , and provided with appropriate rein­ forcement may also act as upstand or down­ stand beams for intermediate floors. Thanks to its uniform surface, reinforced concrete can lend harmony to very diverse structural func­ tions. But even when the load bearing elements remain exposed, the logi c of the construction is not apparent in detail because the arrange­ ment of the reinforcement remains invisible. Building services can be placed in the form­ work and cast i n , or openings can be formed so that subsequent cutting and drilling of the wall is unnecessary. It would seem obvious to save the cost of further finishing materials and leave the concrete exposed. I n contrast to fac­ ing masonry, all the d imensions can be varied at wi l l . It would therefore appear to be a straightforward matter to create a homogenous structure of fair-face concrete. However, the planning and realisation of accurate surfaces require extensive, accurate knowledge of the concretin g process (see "The building enve­ lope", p . 1 1 2) . Surface treatments and formwork materials determine the appearance of concrete surfac­ es. The possibilities range from dead smooth to relief-like, rough surfaces. It is generally true to say that the smoother the surface, the lighter is the colour of the hardened concrete. Formwork Fair-face concrete surfaces always reflect the surface texture, fixings and joints of the form­ work employed. Common materials for forms are solid timber, wood-based products and steel ; but g lass, fibre-cement sheets and plas­ tics are also feasible in principle. The observer can always see whether rough-sawn or planed timber planks, or smooth-faced wood-based boards have been used. Further measures to

1 53

Walls

achieve the required surface finish, e . g . treat­ ment with waxes or oils, also depend on the properties of the formwork material. Apart from self-compacting concrete, the concreting proc­ ess for a wall always has to be carried out in several l ifts to enable the concrete to be com­ pacted by vibration. And each l ift results in m inor changes to the colour of the concrete, which may remain visible afterwards. The l ifts can be signalled by using battens, which are generally necessary for sealing the corners of the formwork anyway. Sharp-edged concrete walls called for elaborate sealing measures to prevent "bleeding" at the edges. And such edges and corners must be protected against mechanical damage during the construction period. Surface treatment The choice of formwork material and surface treatment before or after the concrete has cured provide further architectural options (see "The building envelope", p. 1 1 2, fig. C 1 .23) : •

·

C 4. 5

·

Formwork: - timber p lanks - formwork panels with synthetic resin surface finish - steel forms - plastic forms - textured l i n ings Surface treatment before the concrete has cured: - floating - roughen ing - power floating - furrowin g - brushing - vacuum dewaterin g Surface treatment after t h e concrete has cured: - brushing and washing - pOinting - sand-blasting - acid etching - bush hammering - grind ing - polishing - sealing

Formwork tie holes Regardless of the material used for the forms, the formwork requires additional fixings to pre­ vent it bulging due to the pressure of the wet concrete. After striking the formwork, the holes for these ties remain visible. They can be filled with mortar, closed off with various materials (e.g. fi bre-reinforced cement, plastic, etc.) or even left open. On many buildings the form­ work tie holes form a characteristic pattern on the surface of the fair-face concrete, which, however, requires exact planning and careful workmanshi p .

C 4 .7 1 54

Colour Pigments or special types of cement can be used to modify the colour of the cement and hence the finished concrete (see "Building materials with mineral binders", p . 58, fig. B 3 . 1 4) . Properties Concrete possesses high heat storage capaci­ ty and high thermal conductivity. Fair-face con­ crete walls can provide heat storage capacity in the interior of a building. However, owing to concrete's good thermal conductivity, concrete surfaces normally feel cool to the touch. Durability Fair-face concrete surfaces are very durable. On the other hand, they are immovable and this fact limits the uti l isation options. I nternal concrete surfaces frequently touched by human hands, also the bottom edges of walls rubbed by cleaning equipment, develop a dark patina, which can be removed with high-pressure cleaners and special cleaning agents.

Solid modular walls

The principle of joi ning conveniently sized ele­ ments to form walls is one of the oldest building methods. Ori g inally, the elements used were simply rubble stones as they occurred in nature, but the builders of those times devel­ oped techniques for dressing the stones so that wal l s could be built from regularly shaped units. Man-made clay bricks, whose handling and properties were optimised by moulding and fir­ ing, provided the building industry with a very efficient semi-fin ished product for building walls. In the meantime, the building industry has at its disposal a wide range of masonry units based on mineral materials. The load bearing require­ ments determine the way in which the units are fitted together and the type of binder required. Masonry walls generally exhibit good sound i nsulation properties and are incombustible. Walls of ceramic building materials Until the middle of the 1 9th century, dressed natural stones and homogeneous, fired clay bricks were the only "one-hand-lift" materials available to the bricklayer - the other hand was busy spreading the mortar. German clay brick formats are derived from the thin format ( D F) or the normal format ( N F) . A sol i d clay brick in normal format weighs about 4 kg. As a result of technical progress and increas­ ing thermal i nsulation requirements, large-for­ mat, wire-cut clay bricks (perforated) are now available. Their voids reduce the thermal trans­ mittance and the weight and hence permit larg­ er sizes. To optimise the thermal insulation, some masonry units for external walls now have voids fil led with insulating material and

Walls

tongue and groove end faces for perpends without mortar. Walls of masonry units with mineral binders Unfired masonry units of lightweight concrete, aerated concrete, calcium silicate and gypsum require less primary energy d uring production than clay bricks. And after demolition , such materials can normally be disposed of in land­ fill sites. Calcium silicate masonry units can be reused, i . e . recycled, in the production of fur­ ther units. The highly developed manufacturing techniques for these masonry units result in products with very good dimensional stabil ity that can be laid in thin-bed mortar, and even without mortar to the perpends. Masonry bonds The dimensional coordination rules of building form the basis for assembling the masonry units to form a load bearing masonry wal l . Vari­ ous principles can be appl ied for the different wall thicknesses. Stretcher bond is normally used for large-format masonry units or thin walls in which the width of one unit is equal to the thickness of a wall (half-brick wall) or plas­ tered/rendered walls with no special require­ ments placed on the masonry. The following bonds are suitable for thicker facing masonry built with small-format units: ·

·

·

header bond , in which the thickness of the wall corresponds to the length of one unit (one-brick wall) English bond, with alternating courses of headers and stretchers English cross bond , similar to English bond but with the stretcher courses offset

The use of masonry units with different colours or surface finishes are just two of the numerous decorative options based on the geometrical arrangement of the units. Fig. C 4.7 shows one option in which projecting bricks laid in a regu­ lar pattern create a form of relief. Walls of natural stone

The huge variety of types of stone, formats and surface treatments result in an almost unlimited choice of surfaces for stone walls. Undressed

or partly dressed stones are just as suitable as dressed and polished materials (fi g . C 4.6) . We d istin guish between different types of stone wall depend ing on the degree of working or dressing of the stones. Uncoursed random rubble walls are made from undressed, totally irregular stones, whereas coursed random rub­ ble walls are made from more carefully select­ ed irregular stones obtained from a q uarry. If the horizontal (bed) faces of the stones have been dressed, a coursed square rubble wall is the result, although the stones exhi bit d ifferent formats. The stones of hammer-dressed masonry have approximately orthogonal sur­ faces. The final stage is ashlar walling, which consists of dressed stones all with identical dimensions. Various mechanical treatments can be used on the exposed faces (see "Stone", p. 42) . The courses of stone masonry should be bonded according to D I N 1 053 and DIN 1 8332. Walls of loam bricks

Loam for walls is provided in the form of unburned (sun-dried) bricks, earth-damp pressed bricks (compressed blocks) and l i g ht­ weight loam bricks. They are produced in simi­ lar formats to clay bricks. Owing to their high self-weight, walls of loam bricks have good sound insulation properties. They are also able to reg ulate humidity fluctuations in the interior air through sorption and therefore help to cre­ ate a pleasant interior c l imate. Lig htweight loam achieves more favourable thermal insula­ tion values than tamped loam because of the aggregates used. Loam brick walls are built with a loam or lime mortar and all common bonds and formats are possi ble. The easy workability of loam walls provides the option of numerous mechanical surface finishes. Loam can be wetted with water at any time to create a workable building material (see "Loams for building", p. 46) . Walls of clay bricks

Clay bricks are available in a huge variety of formats and with a whole range of different properties. Sol i d bricks, engineerin g bricks and special faci n g bricks can be used for facing masonry. Plastered or rendered walls can be

C 4.8

built with cheaper wire-cut clay bricks with their advantageous larger formats and better ther­ mal insulation properties. Precision (gauged) clay bricks are factory­ ground to exact dimensions. When building with thin-bed mortar joints, higher permissible compressive stresses are possible than is the case with comparable clay bricks. Good sound insulation is provided by precision clay bricks with large voids subsequently filled with con­ crete storey by storey. Special situations in terms of form (e.g. reveal ) , function (e.g. roller shutter, l i ntel , capping beam) or building tech­ nique (e.g . levelling course) require specials and make-up bricks, which are available for all clay brick formats and types. Properties Clay brick facing masonry is mostly associated with external applications - the most popular use of this material. But as clay brickwork is also suitable for i nternal walls, it can form a good visual l i nk between inside and outside. The vigorous structure of the masonry wal l is particularly worthwhile for large areas of waIl­ ing. The legibility of the building process in a form practised for thousands of years lends walls of clay brick facing masonry a certain archaic character. Sol i d clay bricks and engi­ neering bricks both possess good heat storage capacity and good thermal conductivity. There­ fore, on hot days the heat storage capacity results in a cooler surface temperature which

C 4.4 C 4.5

C 4.6 C 4.7 C 4.8

C 4.9

Loam wall, Catalina House, Arizona, USA, 1 998, Rick Joy Fair-face concrete wall with filled formwork tie holes, Geor9 Schafer Museum, Schweinfurt, Germany, 2000, Volker Staab Natural stone masonry, thermal baths, Vals, Switzerland, 1 996, Peter Zumthor Brick relief as ornamentation, Wolf House, Aggstall, Germany, 2000, Hild & K. Clay brick masonry to an industrial building, Hoechst AG headquarters, Frankfurt am Main, Germany, 1 924, Peter Behrens Gallery for Contemporary Art, Marktoberdorf, Germany, 2001 , Bearth + Oeplazes

C 4.9

1 55

Walls

contributes to an agreeable interior climate. With a careful choice of brick and/or a backing of sound-absorbent material, facing masonry of perforated clay bricks i n which the perforations remain visible is suitable for attenuati ng noise in lecture theatres, concert halls or churches (fig. C 4.8) . Durability Clay brick facing masonry is hi ghly d urable. The - usually - porous surfaces take on a pleasing patina, even internally, and this mini­ mises cleaning requirements. Cleaning with water jets, possibly with the addition of a chem­ ical cleaning agent, is possible. Numerous con­ version projects involving industrial b u i ldings from the 1 9th century have provided the chance to retain such surfaces (fi g . C 4.9) . Walls of lightweight concrete masonry units

The lightweight concrete masonry un its include cement-bonded blocks with aggregates of expanded clay, expanded shale and pumice. Concrete masonry units with pumice aggregate The designations LBH and LBG stand for, respectively, the no-fines and closed-cell light­ weight concrete products. Precast elements of lightweight concrete are generally of the closed-cell variety, but masonry units are open­ cel l . Concrete with pumice aggregate is easy to work, saw and dri l l . The common wal l thickness of 95 mm achieves a fire resistance of at least 1 20 minutes. Solid masonry units are produced in heights of 1 1 5 and 238 mm, hol low units in the formats 820 OF, i.e. up to 490 x 300 x 238 mm. When laying in thin-bed mortar, precision bricks and blocks with ground surfaces are used to enable the thinner mortar joints. There are also mason­ ry units available for building walls without any mortar whatsoever (dry wal l i n g ) . Owing t o their high density o f max. 2 . 0 kg/dm3, solid concrete masonry units with pumice aggregate are also suitable for party walls requiring good sound insulation. Their high dimensional stabil ity renders possible the pre­ fabrication of large-format precision elements for the construction of complete build ings.

Specials for reveals, l i ntels, roller shutters, edges of floor slabs, etc. complement the range of standard units. Concrete masonry units with expanded clay aggregate Expanded clay has similar properties to pum­ ice when used as an aggregate for l i g htweight concrete, and the range of products is simi lar. Expanded clay is produced by firing clay at about 1 200°C. The organ ic constituents of the clay that escape during the firing process require a special extraction plant. The resulting l i g htweight expanded clay beads have a high compressive strength and good thermal insula­ tion properties. Walls of granulated slag aggregate units

These masonry units are made from granulated blast-furnace slag mixed with a mineral binder. They are available in frost-resistant and non­ frost-resistant grades. We d istinguish between the following types: • •

•

sol id granulated slag aggregate un its (HSV) perforated granulated slag aggregate un its (HSL) hollow granulated slag aggregate units ( H H b)

Walls of aerated concrete masonry units

Owing to its good thermal insulation properties, aerated concrete is ideal for constructing both internal and external walls. Even load bearing components can be made from these l i g ht­ weight concrete blocks. Aerated concrete is good for reg ulating humid ity fluctuations in the i nterior air and is water- and fire-resistant; but the heat storage capacity is relatively low.

and dimensions, e . g . D I N 41 65-PP (precision aerated concrete block) 2-0.4-499 x 300 x 249. Facing panels, precision panels and precision blocks can be placed by han d , but large-for­ mat units only with additional plant. Thin-bed mortar is usually sufficient for these d imension­ ally stable bricks, blocks and panels. And tongue and groove end faces enable perpends without mortar. Storey-height, load bearing ele­ ments lead to fast erection times; such ele­ ments must be secured with concrete capping or ring beams. I n future, aerated concrete products will have to comply with D I N EN 771 . Exposed surfaces in aerated concrete are only possible internally. But owing to the material's porosity and vulnerabi l ity to mechanical dam­ age, it is also advisable to add a surface finish (e.g. plaster) here as well . Walls of calcium silicate (KS) masonry units

The d i mensions of calcium silicate masonry units comply with the dimensional coordination system for clay bricks ( D I N 1 06) . For example, D I N 1 06-KS-R- 1 2-1 . 8-4 OF designates a calci­ um silicate brick to be used with thin-bed mor­ tar (R tongue and groove brick) , 1 2 stands for the strength class and 1 .8 the density. Like with clay bricks, the format of calcium silicate bricks is specified in multiples of OF. Owing to their relatively smooth surface finish, calcium silicate masonry units can be used as facing masonry. They are normally light grey to white, but the addition of certain aggregates widens the range of colours on offer. The edges and corners of calcium-sil i cate units are rather vulnerable and therefore must be pro­ tected during work on site. =

Gypsum wall boards

Processing Aerated concrete is easy to work. The blocks can be sawn on site with hand tools, and the prefabrication of large-format elements is wide­ spread. Planning advice Aerated concrete bricks and blocks are availa­ ble in four strength classes. The DIN 4 1 65 notation system is made up of standard, prod­ uct name code, strength class, density class

In contrast to all the foregoing masonry units, gypsum wall boards to EN 1 2859 are not per­ mitted for load bearing walls. Nevertheless, their incombustib i l ity and good sound insula­ tion properties make these boards ideal for many purposes. They save space, are easily demounted and re-erected , are highly vapour­ permeable and their sorption behaviour improves the interior c l imate. Gypsum wall­ boards are easily cut and worked to accommo­ date building services, and therefore are fre-

C 4 . 1 0 Modular construction with insulating bricks C 4.1 1 Modular construction with prefabricated timber elements C 4 . 1 2 Wall of glass blocks, Academy of Arts and Archi­ tecture, Maastricht, Netherlands, 1 993, Wiel Arets C 4 . 1 3 Curved wall of profiled glass, office building, Erlangen, Germany, 2002, Wulf & Partner C 4 . 1 4 Larch wood lining, Regional Rhenish Museum, Bonn, Germany, 2003, Architektengruppe Stutt­ gart (Lohrer, Pfeil, Bosch, Herrmann, Keck) C 4 . 1 5 Detail of a timber-frame building, Eifel region, Germany C 4. 1 0

1 56

C 4. 1 1

Walls

quently used as a false wall concealing service ducts and shafts. The building materials i ndustry provides gyp­ sum wall boards in three d ifferent densities and thicknesses of 50, 70, 80 and 1 00 mm; one common format is 666 x 500 mm. The boards have tongue and groove edges which are glued together. After filling the joints, the result­ ing flat surface is suitable as a substrate for wallpaper and coatings without the need for plaster. Walls of glass bricks

G lass bricks can be used to construct translu­ cent walls. The l i g ht transmittance is approx. 80%, but less for the body-tinted g lass bricks. The standard sizes are 1 50 x 1 50 mm and 300 x 300 mm, with thicknesses of 80-1 00 mm. Glass bricks have an air-filled void and achieve U-values of approx. 1 .5-3.2 W/m2K. In terms of thermal insulation, the mortar joints represent a weakness, and this is why jointin g techniques without mortar are now unavailable. Glass bricks provide fire resistance for up to 60 minutes, but do not prevent heat radiation. They provide some sound insulation but cannot carry any loads. Careful planning and construction of movement joints and sliding connections is the only way of guaranteeing that g lass brick walls remain free from all restraint. The high light transmittance without transparen­ cy also permits the use of glass bricks in areas where windows would be undesirable. Glass, once separated from other debris, can be fed back into the manufacturing process. The dura­ bility of a glass brick wall is l i m ited solely by its mortar joints.

Solid linear methods of construction

Linear elements can be joined together hori­ zontally or vertically to form walls. Vertical joints between room-high elements is usual, horizon­ tal joints are rather rare. Walls of prefabricated gypsum wallboard panels

Room-high prefabricated gypsum wallboard panels are covered by draft standard prEN 1 39 1 5. Their properties and applications are similar to those of gypsum wal lboards (see p. 1 56) .

Walls of profiled glass

Profiled g lass represents a cheaper alternative to sheet g lass for translucent, non-load bearing walls (fi g . C 4. 1 3) . D I N 1 249-5 covers the vari­ ous types, d istinguished by the d ifferent web and flange dimensions of these glass channels, which are normally produced in lengths up to 7 m. Profiled g lass with a wire in lay fulfils the requirements regarding protection against fly­ ing fragments should the glass the shattered by balls or similar objects. Profiled glass is available in various colours, also in extra-clear and toughened versions (see "G lass", p. 86) . Walls of profiled glass are usually built with alu­ minium sections for retaining the glass. Vertical joints are filled with silicone. It is therefore pos­ sible to d ismantle and reuse such walls.

Small-format modular systems

Industry provides a number of systems with which walls can be joined together l ike mason­ ry. In most cases these are l i ghtweight, stacka­ ble hollow units which can be filled if necessary and are hence also suitable for self-build projects. Specially shaped hollow units of polystyrene i nsulating material can be connected by means of tongue and g roove joints and the resulting continuous cavity filled with concrete. They are suitable for constructing walls without form­ work. All the elements req uired for the system, e.g. prefabricated corners, window reveals, etc . , are available. Another system uses prefabricated timber boxes which are joined together to create a fin­ ished wall surface. When the void is filled with a loose insulatin g material, these boxes can be used for external walls as wel l . Buildings erect­ ed with this system req u i re very few tools. Solid timber and wood-based boards are used for the elements themselves. The various products made from clay or l i g ht­ weight concrete masonry units, with their voids filled with i nsulating material, are among the small-format systems for external walls designed to satisfy thermal insulation req u i re­ ments. The perpends of these units are in the form of tongue and groove connections in order to minimise thermal losses via the joints.

Walls in log construction

Planed or rough-sawn rectangular timber sec­ tions or debarked round trunks are joined by notching the members and interlocking these at corners and intersections. As the jointing and the floor construction must take into account the span of the timber, room widths up to approx. 4.50 m are common. Walls in log construction possess a relatively coarse aes­ thetic. But the methods of construction that dominated the pre-Industrial Age are rarely used nowadays.

Large-format modular systems

Constructional considerations are usually the main reason behind a decision to construct walls with modular precast concrete, prefabri­ cated timber or large clay elements. The prop­ erties of the materials are not significantly d if­ ferent to the methods of construction already described. One example of a system using large clay elements is the Hotel Management School in Nivilliers (see Example 1 9, pp. 24547) . Timber panel and timber frame methods also permit the prefabrication of large elements C 4. 1 5 1 57

Walls

C 4 . 1 6 Frame construction with freestanding partition, Tugendhat House, Brno, Czech Republic, 1 930, Ludwig Mies van der Rohe C 4. 1 7 Systematic classification of wall claddings and linings C 4 . 1 8 Laminated veneer lumber, "Green U niversity" Pavilion, IGA, Stuttgart, Germany, 1 993, Cheret & Bozic C 4 . 1 9 Wall lining of curved plywood, Nord LB bank building, Magdeburg, Germany, 2003, Bolles & Wilson C 4.20 Staircase with MDF lining, art gallery, Winterthur, Switzerland, 1 998, Gigon + Guyer

C 4. 1 6 that are subsequently covered with wood­ based products. Such wall assemblies are compared in the section on mUlti-layer walls (see p. 1 58) . Cross-laminated timber

Modern gluing techniques result in efficient solid timber constructions. Side boards are g lued together in cross-band­ ed plies to form 50-300 mm thick elements i n formats up to 4.80 x 20 m . Such sol i d wal l com­ ponents offer numerous advantages compared to log construction: shrinkage and fissures are essentially eliminated, the material th ickness can be reduced and the walls can be used to stabilise the building. The prefabrication of walls to match the height of the building - with millimetre accuracy - considerably reduces the construction time. Despite the large consumption of materia l , the use of less expensive boards of lower qual ity renders this form of construction economic. The surfaces can be left exposed where appearance is not of primary importance; but in future better surface finishes can be expected, which will extend the range of applications (fi g . C 4. 1 4) .

Single-layer walls

Walls that include loadbearing, l i near-type ele­ ments within the wall thickness represent the transition to frame construction. The wall sur­ face is created by filling the intermediate spaces between the load bearing components (single­ layer) or by covering them (multi-layer) . The most frequent application of this form of construction is in traditional timber-frame con­ struction with its flush infi l l panels of masonry, loam or mineral-bonded products. Framed structures with load bearing members made from steel or reinforced concrete do not meet modern thermal i nsulation requ i rements and therefore require a multi-layer wall con­ struction. Timber-frame construction is general­ ly conceived for a complete building, i.e. for the external walls as wel l . Since the Thermal I nsula­ tion Act (now replaced by the Energy Economy Act) came into force, solid timber components

1 58

have also req uired thermal i nsulation to reduce the thermal transmittance, i . e . since then ex­ posed timber frames are only possible internally. The easily worked loam materials provide another option for infill panels in addition to clay bricks and mineral-bonded products. The good capi l lary action of loam helps to reg ulate mois­ ture levels: it prevents excessive moisture i n the wood a n d hence protects the construction.

Multi-layer walls

The spread of methods of construction with lin­ ear load bearing members has promoted the development and variety of mUlti-layer wal l constructions q u ite decisively. We d istinguish here between loadbearing , bracing and non-load bearing walls. Coverings of planks or boards can help to share the load or to create a shear wal l helping to sta­ b i l ise the structure. However, other forms of cladding (external) and lining (internal) may be provided merely for acoustic or fire resistance reasons or simply to upgrade the appearance.

Non-Ioadbearing walls

In frame construction the reduction of the verti­ cal load bearing members to free-standing col­ umns enables the interior to be subdivided regardless of the floor spans. The load bearing structure becomes separated from the interior boundaries, which can now be arranged as required with non-load bearing walls (parti­ tions) . Ludwig Mies van der Rohe's German Pavilion in Barcelona or Tugendhat House in Brno (fig. C 4. 1 6) are examples of the faithful implemen­ tation of this principle. Apart from the freedom gained for the interior layout, frame construc­ tion in steel, reinforced concrete or timber re­ sult in flexibility and shorter construction periods. Construction

Timber or metal vertical members (studs) gen­ erally provide the basic framework for multi­ layer walls. Timber studs usually match the thickness of the wal l . If metal is used, an enclosing channel section usually provides the framework in which the studs are positioned at a reg ular spac i n g .

Loadbearing walls

The walls with a load bearing function are all those constructions with load bearing elements between the two wall surfaces, e . g . : · • ·

timber studding timber frame timber panel

In timber studding the covering material has no loadbearing function. Bracing is provided in the form of, for example, d i agonal metal ang les, sheet metal or metal straps. Besides timber planks and boards, numerous industrially man­ ufactured panels are available for use i nternally and externally to match the specification. Timber frame construction normally requires a covering material that transfers the horizontal forces to the foundations. Wood-based boards are suitable for this. In timber panel construction the covering mate­ rial carries part of the vertical loadi n g . Cross­ lami nated timber, mUlti-ply boards and laminat­ ed veneer l umber satisfy such req u i rements.

Requirements

A huge variety of materials is available for wal l claddings a n d linings. The selection criteria include: •

•

•

•

Constructional requirements: - load bearing - bracing - non-Ioadbearing Building performance requirements: - sound insulation - moisture control - thermal insulation - fire protection - room acoustics Functional requirements: - mechanical protection - inclusion of building services Architectural requirements: - levelling the surface - concealing of building services - colour - feel

Walls

O_ lid __ tim _ b _ e_ r _-,1 ,_ - S _ -

1

tongue and groove boards

3-core plywood

Wood-based core plywood

Layered timber

5-core plywood

solid timber panels

block board (ST))

laminboard (STAE)

Particle boards flakeboard

oriented strand board (OSB)

particleboard (P)

laminated veneer lumber (LVL)

extruded particleboard (ES)

building-grade veneer plywood (BFU)

tubular particleboard (ET)

Wood fibreboards medium-density fibreboard (MDF) porous fibre boards (SB)

medium boards (MBU MBH)

hardboard (HB)

Boards with mineral binders gypsum-bonded partic le boards

cement-bonded particleboards

Loam boards lightweight loam boards

fibre-cement sheets plasterboards

fibrous plaster boards cement fibreboards perlite boards

C 4. 1 7

Owing to their low weight and low price, miner­ al-bonded boards are often used in practice. A 1 1 5 mm plasterboard partition adds approx. 25 kg/m2 to the floor load, but a sol i d wal l of the same thickness approx. 1 40 kg/m2. Lightweight partitions can therefore be positioned as required irrespective of the load-carrying capacity of the floor. D I N 4 1 03 prescribes the necessary stability, i.e. a rigid, immovable con­ struction. The choice of the materials for studs, insulation and lining enable the walls to meet d ifferent req uirements. Sound insulation Simple sound insulation requirements are achieved by filling the voids with an appropri­ ate insulating material. If the two wall covering materials are attached to i ndependent frames, the sound insulation properties improve consid­ erably. Joints and junctions with adjoining com­ ponents frequently form weak spots, which therefore must be especially carefully detailed according to DIN 4 1 09. Fire protection Claddings and linings made from mineral­ bonded boards are fire-resistant. Depending on the arrangement of the layers, fire-resist­ ance classes (to D I N 4 1 02-2) from F 30 to F 90 are possible.

Building services options Owing to the ease of d ismantl ing, multi-layer walls can be used to conceal service ducts and shafts. Many lining materials are readily workable and are therefore also suitable for instal ling at a later date. Mechanical protection The junctions with load bearing components, e . g . soffits of concrete floor slabs, must take into account the deflections and deformations of such components so that non-load bearing partitions are not damaged. A sliding detail at the junction with the soffit will prevent loads being transferred into the wal l . Lining, levelling the surface Walls covered with mineral-bonded boards are suitable for d i rect painting or wallpapering after the joints have been filled. Such walls appear l i ke sol i d components, but a comparison reveals the smaller construction tolerances. Therefore, in existing buildings the walls are often lined without framing in order to correct irregularities at minimum cost. To prevent unsightly cracks due to structural movements or fluctuating temperaturelhumidity, careful work­ manship is necessary at joints and junctions. Claddings and linings of wood and wood-based products

Wood-based boards can help to carry the loads and brace a timber structure. Only M D F

C 4.18

C 4. 1 9

boards a n d wood-fibre insulating boards are not approved for such applications. High-strength mUlti-ply boards of beech wood (BFU-BU) re­ present a special case, but the production costs of these seldom justify their use as load bearing components. The class of wood-based product must be chosen to suit the particular application (see "Wood and wood-based products", p. 72) . Solid timber The connection of boards to form a complete wall surface is usually achieved by means of tongue and g roove joints; butt-jointed rectan­ g ular sections can be used as an alternative. One visual feature here is the longitud inal joints which can determine the structure of the wall finish. Planed or sanded boards - with exposed or concealed fixings - can be left uncovered. Wood-based products Wood-based products are preferred for cover­ ing walls in timber structures. If the wood-based products remain visible in the finished struc­ ture, joints corresponding to the maximum d i mensions (see "Wood and wood-based pro­ d ucts", p. 72, fig. B 6. 1 6) must be considered at the planning stage . But, overlapping and tongue and groove joints are all possible. As the edges of multi-ply boards match the q uality of their faces, they can remain visible. The stacked plies visible on the edges of build­ ing-grade plywood and laminated veneer lum­ ber possess a certain charm and are therefore

C 4.20

1 59

Walls

also used as a decorative feature. The faces of the boards consist of solid timber or low-qual ity veneer. If required for acoustic purposes, CNC routing can create virtually any type of perfor­ ated or slotted structure. Fig. C 4. 1 8 shows an example with walls of exposed laminated veneer lumber.

screwed or tacked to a framing and can even be bonded to masonry or concrete with dabs of mortar. Ceramic tiles can be applied directly to the surfaces using the thin-bed method.

Claddings and linings of mineral-bonded boards

Finishing the joints After filling the joints, the boards can be coated or covered without any further surface treatment. This enables the creation of seamless surfaces which, provided with the right finish, can lead to a "purist" effect (fig . C 4.2 1 ) . To g uarantee the long-term homogeneous appearance of walls and soffits l ined with mineral-bonded boards, the joints must be properly planned and properly executed. Elastic joints are re­ quired at the junctions with other components so that the changes in length of the building materials d ue to temperature and humidity do not result in any cracks. It is frequently the case that mechanical loads or unacceptable climate fluctuations d uring the construction phase cause cracks in the filled joints between the boards. Such joints can be covered with glass fibre-reinforced tapes which prevent cracks. As joints on the surface can be seen (especial­ ly when the l i g ht strikes the wal l at an acute angle) , even after the finishes are in place, the filling of such joints requires special attention. A draft standard proposes four levels of quality: Basic filling (0 1 ) req u i res closing of the joints and holes caused by the fixings. I n standard filling (0 2) the transitions are lev­ elled to such an extent that a covering of woodchip wallpaper or plaster is possi ble. Special filling (0 3) req u i res fi l l i n g over a large area and subsequent rubbing down. Extra special filling (0 4) involves fil l i n g , skim coatin g and rubbing down of the surface over the entire area to guarantee a suitable substrate for coatin g materials, smooth wallpapers and h igh-quality surface finishes. Only grade 0 4 is adequate to rule out visible joints even when the light strikes the wall at an acute angle.

With the exception of plasterboard, this group of boards can also be used for load-sharing and bracing purposes in timber structures. How­ ever, they are primarily employed as linings on non-load bearing partitions, as dry lining and owing to their good behaviour in fire - for encas­ ing components at risk. These boards are nailed,

Gypsum-bonded particleboards Gypsum-bonded pressed particle boards can be used as load-sharing and stiffening compo­ nents on wall panels for timber houses in panel construction (see "Building materials with min­ eral binders", p. 6 1 ) .

Wood-based core plywood Wood-based core plywood, in its various forms, is used mainly for intemal fitting-out and furniture, and is frequently finished with a h i g h-quality veneer. The edges of veneered boards req u i re an edge trim, e . g . of solid wood, for visual rea­ sons. Particleboards Particleboards are frequently used as a back­ ing material for veneers or robust coatings, e . g . melamine resin or coating materials m a d e from resin-saturated , pressed papers ( HPL high­ pressure laminate) . The untreated edges of particleboards are porous and vulnerable to damage. Particleboards are frequently used to create a rigid covering so that the wall can be classed as a shear wall , but also simply as lin­ ings to walls, soffits and partitions. Extruded tubular particle board with a perforated coating or covering on both faces (LRD) are produced for acoustic purposes. LMD is the designation for an extruded particleboard without tubular voids. =

Wood fibreboards Medium-density fibreboard (MDF) is available in several colours. The edges exhibit only minor structural differences to the hardwearing, dense faces, i.e. these boards are suitable for walls and furniture even without edge protec­ tion . Fig. C 4.20 shows a staircase with a lining of medium-density fibreboard left exposed.

•

•

•

•

Cement-bonded particleboards Cement-bonded pressed particleboards (EN 634) are suitable for use as a fire-resistant coveri n g , as a backing for veneers and as a substrate for ceramic tiles (see "Building mate­ rials with mineral binders", p. 61 ) . Fibre-cement sheets These weather-resistant products can be used to create very durable wal l surfaces both inter­ nally and externally. Coloured surfaces can also be produced directly with these sheets as there is now a wide range of colours available achieved with pigments and different aggre­ gates. Plasterboards Plasterboard and fibrous plasterboard are used for the vast majority of wall and soffit linings. I n comparison t o masonry a n d concrete, plaster­ board surfaces feel much warmer because the low total mass heats up quickly. Plasterboard in the form of dry lining or on a framework of tim­ ber or metal sections is ideal for building large, flat areas of walling with minimum effort. Metal sections to D I N EN 1 41 95 are widely used as a supportin g construction. D I N 1 81 81 or, in future, D I N EN 1 4566 sti pulates the minimum and maximum spacings for the metal sections. The recommended spacings depend on the fixings and the thickness of the board. Addi­ tional linings in the form of m ineral-bonded boards attached with adhesive, or ceramic fin­ ishes, must be considered when deciding on the supporting framework. In the case of multi­ layer linings, the joints in the d ifferent layers should be offset.The choice of board for a wall depends on the fire resistance, moisture and strength requirements. Cement flbreboards Cement fibreboards are currently not covered by any standard . They can be used as a load­ sharing layer in timber structures or - with building authority approval - as temporary weather protection. Perlite building boards I n contrast to plasterboards, perlite building boards are water-, frost- and weather-resistant, and are therefore useful as linings to wet interior areas (see "Building materials with mineral binders", p. 61 ) . They must be attached with screws in the predrilled holes and joints must be sealed with a special adhesive. Lightweight loam building boards

Lightweight loam building boards should be screwed to a supportin g framework (or con­ crete or masonry wal l ) . Otherwise, they may be handled just l ike other dry l ining products. They are usually finished with a coat of plaster (see "Loams for building" , p. 46) .

C 4.21

1 60

C 4.21 Lining of plasterboard, Frieder Burda Collection, Baden-Baden, Germany, 2004, Richard Meier C 4.22 Life cycle assessment data for walls and linings

Walls

Solid walls Layers , for origin of data see "Life cycle assessments", p. 1 00 Solid homogeneous walls reinforced concrete

reinforced concrete (grade C 25/35), 2% steel content (FE 360 B), 200 mm

Solid modular walls loam bricks'

air-dried loam bricks, p loam mortar

=

1 400 kg/m3, 240 mm

aerated concrete bricks

aerated concrete bricks (PPW 4-0.6 NuF), 240 mm masonry mortar, MG I I I

PEI primary energy non-renewable [MJ)

PEI primary energy renewable [MJ)

GWP global warming [kg C02 eq)

ODP ozone depletion [kg R 1 1 eq)

AP acidification [kg S02eq)

EP eutrophication [kg PO. eq)

POCP summer smog [kg C2H. eq)

650

83

45

0.00001 0

0.21

0.0 1 3

0.0 1 0

I

c=::=:=J

=

0.01 2

0.001 1

0.001 0

96

-

410

calcium silicate bricks

calcium silicate bricks (KSL 1 211 .4) , 240 mm masonry mortar, MG 1 1

1 .2 14 247

lightweight concrete bricks with pumice aggregate

- with pumice aggregate (VBL 2), 240 mm masonry mortar, MG I I I

I

=

51 7

14

4.2 0

65 5.1

=

56

0

0

8.9

0

vertically perforated clay bricks

599

12

79

0

timber stud wall

plasterboard (type A), 1 2.5 mm timber studs, 80 x 40 mm mineral wool, 40 mm plasterboard (type A) , 1 2 .5 mm

Wall and soffit linings Layers , for origin of data see "Life cycle assessments", p . 1 00 Mineral linings

plasterboard'

plasterboard (type A), 1 2.5 mm screw fixings, edge detail with softwood battens loam building board

fine loam plaster, jute fabric, 4 mm loam building board, 20 mm timber framework, screwed, 24 mm glass wall

- tough. safety glass, sound insulation class SSK 3), 8 mm acrylic joints

Timber linings

timber boards

timber boards (spruce, t&g) 1 9.5 mm screwed

0. 1 3

1 82

1 79 =

PEI primary energy non-renewable [MJ)

PEI primary energy renewable [MJ)

97

50

-

84

-

239

40

-

CJ

2.0

3.8

281

CJ

-5.9

0

0.037 0

0.092

0.0076

c==J

CJ

0.014

0.030

0.0036

0.0050

0

0.0070

=

0.064

0.0076

0.01 3

=

c:==J

c==J

GWP global warming [kg C02 eq)

ODP ozone depletion [kg R1 1 eq)

AP acidification [kg S02 eq)

EP eutrophication [kg PO. eq)

POCP summer smog [kg C2H. eq)

1 .2

0

0.030

0.0034

0.0060

c::::::=J

c::::::=J

0

0.022

0.0028

0.0030

=

c=::::J

0

0.034

0.0035

0.0040

=

c::::::=J

0

0.01 5

0.00 1 8

0.0050

=

=

0

0.0069

0.032

0

-0.2

8.9

-26

0

0

0

0.060

oriented strand board'

40

87

-9.7

0.00000 1 6

0.Q1 8

40

-

I

c:==J

87 c:==J

0

c=::::J

0

-

0

c==:=J

-23

particle board •

c==J

0.01 1

540

particleboard P1 , 1 9 mm screwed

I

0.0072

1 77

OSB, 19 mm screwed

0.0 1 3

0. 1 5

veneer plywood

veneer plywood, 22 mm screwed

0.0 1 8

c:=:::J 2.5

Stud walls

I

=

0

1 86

vertically perforated clay bricks (HLz 1 211 .2), 240 mm masonry mortar, MG II

0

26

gypsum wallboard

gypsum wallboard, 1 00 mm gypsum mortar, MG IV

0.25

0

-9.7

0

I

I

0.00 1 8

t

I

0.0020

c:::J

=

0

0.01 8

0.00 1 8

0.0020

c:::J

=

0

C 4.22

1 61

Intermediate floors

C 5. 1

I ntermediate floors span over interior spaces, forming the ceiling but at the same time the floor for the storey above. The soffit has a cru­ cial effect on the room below. As pointed out by Gottfried Semper, the German word for i ntermediate floor and ceiling is " Decke", which is also the word for blanket, and stems from the textile canopy of a baldachin, a symbol for the elevation of a place. The expanding spectrum of materials and forms of construction is particularly evident in the development of intermediate floors. Prior to the I ndustrial Revolution there were basically only two options for building i ntermediate floors: stone vaultin g , whose solid, heavyweight form of construction demanded a considerable structural depth , and timber joists, which spanned the interior horizontally from wall to wal l . The latter option prevailed wel l into the 20th century. The lengths of timber available restricted the spans of timber joist floors with­ out i ntermediate columns, whereas the com­ pressive strengths of the materials l i m ited the dimensions of vaulting. During the 20th century, efficient systems employing concrete, steel and combinations thereof expanded the options presented by sol i d masonry and timber-frame forms of con­ struction, and enabled large spans with mini­ mal structural depths. I n particular, the intro­ duction of concrete floor slabs spanning in two directions had a fundamental impact on archi­ tecture. Le Corbusier's " Dom-Ino" reinforced

C 5.1 C 5.2 C 5.3 C 5.4

MUSAC Museum, Le6n, Spain, 2005, Mansilla y Tun6n Overview of floors Systematic classification of construction principles for intermediate floors Examples of solid intermediate floor forms a waffle slab b hollow-core slab c composite slab with trapezoidal profile metal sheeting d composite flat slab e prestressed hollow-core slab f hollow-block floor

concrete frame system for mUlti-storey build­ ings was the harbinger of the frame construc­ tion widespread these days. In timber engi­ neering, new wood-based and g lued timber products resulted in longer spans. The materials for intermed iate floors account for a considerable proportion of the mass of a building and so their choice has a critical effect on the l ife cycle assessment of a building. Exposed forms of construction represent a challenge from both the structural and the aesthetic aspects. Stability I n terms of stability, the feasi ble spans are, in the first instance, crucial to the choice of mate­ rial for an intermediate floor. As a rule, the inter­ mediate floor has to accommodate horizontal forces, e . g . from wind loads, vertical eccentrici­ ties and earthquakes, and transfer these to the bracing walls. Essentially, depth of construc­ tion, consumption of materials and self-weight have to be balanced against one another. I n doing so, there should b e a reasonable rela­ tionship between the self-weight of the con­ struction and the imposed loads it has to carry. The optimisation of intermediate floors with respect to these parameters - also in relation to their economic viabil ity - permits many d ifferent solutions. The stiffness of an intermediate floor must be considered in order to avoid damage to parti­ tions caused by excessive deflection or vi bra-

1 2 3 4 5 6 7

intermediate floor (between storeys) floor over basement basement floor slab, unheated ground floor slab, heated floor to unheated roof space roof floor with soffit in contact with outside air C 5.2

1 62

I ntermediate floors

Timber intermediate floors

In situ concrete

Partly prefabricated

reinforced concrete steel-concrete flat slab composite flat slab flat slab with flared column heads waffle slab hollow-core slab glass-concrete slab

I n situ concrete

Partly prefabricated

Fully prefabricated

r i b bed slab concrete plank precast concrete prestressed hollow- floor slab core slab composite floor T-beam slab beam grid hollow-block floor aerated concrete slab two-way-span prestressed conhollow-block floor brick arch floor crete planks/floor double-T floor units beams with in situ concrete topping

tions in the case of very slender intermed iate floors. And depending on their application within the building, there may also be requirements to be satisfied regarding thermal and sound insula­ tion as well as fire protection. Fig. C 5.2 i l l us­ trates the different floor types in a building. Thermal insulation and heat storage capacity Intermed iate floor constructions that form a boundary between interior and exterior must normally be insulated. Owing to their dimensions and mass, intermediate floors have a crucial influence on the interior climate because of their heat storage and sorption capabilities. I n energy-efficient bui ldings their mass is inten­ tionally used for storing heat. The activation of building components (containing a grid of water pipes) enables the surface temperatures of inter­ mediate floors and hence the air temperatures of the adjoining interior spaces to be regulated . Sound insulation Solid (heavyweight) intermediate floors provide good insulation against the transmission of air­ borne sound. Lightweight intermediate floors, e.g. in timber, require a multi-layer form of con­ struction in order to attenuate impact and air­ borne sound transmissions between adjoining storeys. More stringent impact sound req u i re­ ments will require the floor finishes to be sepa­ rated from the floor itself (see "Floors", p. 1 7 1 ) .

a

Timber joists

Timber elements

dowelled beam floor four-piece beam floor joist floor isolated ceiling floor joist floor with clay bricks

floor of edge-fixed boards cross-laminated timber floor box-element floor timber element floor LVL ribbed timber floor

Fire protection For fire protection purposes, we distingu ish between intermed iate floors, ground floors over basements, and roofs. Apart from roofs, floor constructions must be desig ned for a fire resis­ tance of 90 minutes. Only when the u ppermost intermed iate floor in residential buildings is < 7 m above the surrounding ground level do less stringent requirements apply. Differentiating according to structural design The d istinguishing feature of the various forms of intermediate floor construction is their struc­ tural design . Two-way-span systems ( e . g . flat slabs) can be supported at ind ividual points. One-way-span systems require linear supports. The soffits of both of these forms of intermedi­ ate floor construction can be flat, or can include visible loadbearing members. However, the transition between these two forms of construc­ tion is not clear-cut. We can also classify the i ntermediate floor systems according to their degree of prefabrication and the different mate­ rials employed.

Timber composites solid timber-concrete composite floor timber beamconcrete composite floor

C 5.3

without any visible changes in d imensions (e.g. by using an irregular column g ri d ) . Concrete intermediate floors � 1 00 mm deep are classed as fire-resistant without a screed. The concrete cover to the reinforcement must be in accord­ ance with D I N 4 1 02 . A s their depth increases, s o the ability o f solid concrete intermediate floors to insulate against airborne sound transmissions also increases. Flat soffits ease the planning of building servic­ es and partitions. The desire to optimise the ratio of formwork to use of material (concrete) has led to numerous, diverse forms of intermediate floor construction. Generally speaking, setting up formwork is a costly business, which is why simplification or effective substitutes are a prime goal of ration­ alisation measures. The possibilities range from reusable formwork systems to all types of pre­ fabrication. In situ concrete intermediate floors

The two-way-span in situ concrete intermediate floors include flat slabs with and without col­ umn heads, waffle slabs, hollow-core slabs and glass-concrete slabs.

Two-way-span intermediate floors

Concrete is often selected for i ntermediate floors because it offers numerous solutions and is very durable. When used i n the form of a flat slab, the reinforcement can be designed to provide the necessary load bearing capacity

Flat slabs without column heads This form of reinforced concrete slab is sup­ ported d i rectly on the columns without the need for any downstand beams. Flat slabs require more reinforcement than slabs supported on beams, but this is offset by the lower cost of the

b

c

/

/

d

e C 5.4

1 63

Intermediate floors

simplified formwork. The installation of building services is also much easier; merely the posi­ tions of openings near columns have to comply with minimum clearance requirements. The two-way load bearing behaviour enables the columns to be positioned on an irreg ular grid if desired, and openings of any shape and size are also possible (fi g . C 5.5) . Depending on the plan geometry, the depth of the slab can be estimated at 1 /30 to 1 /35 of the span. If parti­ tions are to be built on the slab, more stringent requirements must be met in order to guaran­ tee adequate stiffness (surcharge for parti­ tions) . The casting of building services (e.g. grid of cooling pipes for activating the compo­ nent, lights, electric cables) into the slab is very easy during construction, but extremely costly afterwards. Flat slabs with column heads These are slabs supported on individual col­ umns but with taperi n g , so-called flared, col­ umn heads. The h igher cost of formwork is worthwhile for longer spans and /or heavier loads if the punching shear around the col­ umns becomes excessive and a deeper slab is not possible. The routing of services is some­ what restricted here owing to the column heads and the clearances required for openings.

spheres, held in position by the reinforcement (fig . C 5.4 b ) . The advantages are good flexural stiffness and the comparatively inexpensive production on site. Glass-concrete slabs This is a composite floor system made up of pressed glass blocks and reinforced concrete. The glass blocks are held in place by a grid of reinforcement in both d i rections simi lar to the waffle slab (fi g . C 5 . 7) . Partly prefabricated intermediate floors (two-way­ span)

Two-way-span intermediate floors can be pre­ fabricated by casting in steel sections (depth equal to depth of slab) instead of reinforce­ ment. Composite flat slabs Steel beams carry the loads and visibly divide the intermed iate floor into bays. I n most cases the steel beams are special sections. The columns are positioned beneath the steel beams. Composite flat slabs enable longer spans than reinforced concrete for the same depth of slab and have flat soffits (fig . C 5.4 d ) .

One-way-span intermediate floors

Waffle slabs Waffle or coffered slabs carry loads i n two directions. The spacing of the ribs in both directions can be 300-1 500 mm. At larger spacings the load bearing behaviour is similar to that of a beam grid. The structural bond between the ribs (i.e. the web) and the floor slab itself (i.e. the flange) is critical if long spans are to be achieved. The complex soffit is easy to achieve with any one of a number of formwork systems (pan forms) . The bays of the waffle slab are usually square or rectangular (fig. C 5 . 4 a) , but triangles are also possible (fi g . C 5. 6) . Hollow-core slabs A BubbleDeck® is a two-way-span, hollow-core slab without downstand beams (i.e. flush soffit) . The self-wei g ht of flat slabs over longer spans can be reduced by casting in hollow plastic

C 5.5

1 64

Reinforced concrete ribbed slabs An intermediate floor with parallel downstand beams at a spacing of approx. 300-700 mm is known as a ribbed slab. In comparison with a reinforced concrete flat slab, the interaction of the reinforcement concentrated in the vertical "web" ( i . e . rib) and the horizontal concrete "flange" i n the compression zone leads to a lower weight for the same depth of slab, and enables longer spans (up to approx. 1 5 m ) . Reusable steel or plastic forms are employed to ease the work on site.

These intermediate floors transfer the load bear­ ing principle of the timber joist floor to soli d , monolithic forms o f construction. Here, too, optimisation between the high cost of form­ work, beams, etc. and use of materials has led to a multitude of solutions. The various types of intermediate floor are d istinguished by their materials, geometries and degrees of prefabri­ cation . In situ concrete slabs

One-way-span slabs of in situ reinforced con­ crete are often used for longer spans. The objective of this form of construction is minimal self-weight, which usually involves more costly formwork.

C 5.6

Prestressed hollow-core slabs Casting-in void formers (e.g. cardboard tubes) in one d i rection saves material and weight on long-span intermediate floors. These slabs are usually precast and prestressed. Owing to the greater depth and the prestress, longer spans are possible than with reinforced concrete flat slabs of the same weight. Partly prefabricated intermediate floors (one-way­ span)

To rationalise the construction sequence, some intermed iate floors only use in situ concrete to complete the floor construction. The shorter drying and curing times and the lower transport costs - compared to fully prefabricated floors make these systems economic. In most cases partly prefabricated floors require no formwork.

Concrete plank floors I n this floor the prefabrication is limited to the tension zone of the component. The concrete topping (compression zone) is cast and the upper layer of rei nforcement fixed on site. This form of construction therefore combines the advantages of permanent formwork (the planks) and the (usually) high-quality soffit that can be achieved with precasting. This form of intermediate floor can act as a horizontal, stiff­ ening diaphragm. Its readily visible joints distin­ guish it from the sol i d in situ slab. Composite floors We distinguish between composite action of the primary construction (composite beams) and that of secondary constructions (compos-

C 5. 7

I ntermediate floors

ite floor slab with profiled steel sheeti n g ) . The two approaches can also be combined. Composite beams Efficient intermediate floors with a low structural depth can be produced by bonding the steel beams to the concrete slabs - a similar effect to the reinforced concrete ribbed slab - instead of just placing the one on top of the other. Shear studs and shear connectors welded to the steel beams in various arrangements create the bond between the steel sections and the overlying concrete slab. Composite floor slabs Trapezoidal profi le steel sheeting with reinforc­ ing bars laid in the ribs represents an effective intermediate floor system when laid on steel or timber beams. The sheet metal serves as per­ manent formwork and can be supported on the beams at various levels (fig . C 5.4 c) . Trapezoi­ dal profi le steel sheeting with special profiles can even replace the bottom (tension) reinforce­ ment altogether. Certai n types of profi le or em­ bossing of the sheet metal can create a bond between steel and concrete. Composite floor slabs with standard trapezoi­ dal profiles achieve a fire resistance of up to 60 minutes. I nd ividual approval is possible for up to 90 minutes. Some manufacturers combine trapezoidal pro­ file steel sheeting and shear studs/connectors to produce a form of construction with particu­ larly low structural depths. Hollow-block floors These forms of intermediate floor are made up of the following components: • •

•

load bearing beams (non-load bearing or load-sharing filler ele­ ments (of various materials) concrete topping if req u i red

The different degrees of prefabrication of the beams and filler elements results in various structural systems, which with a concrete top­ ping and reinforcement can even act l ike a ribbed slab. Construction times and the level of construction moisture in the building vary de­ pend ing on the proportion of in situ concrete. Solid precast concrete beams (extending over the full depth of the construction) , lightweight steel sections, reinforced concrete planks or clay channels (fi lled with concrete on site) (fig. C 5.4 f) can be used as the loadbearing members. One advantage of this type of intermediate floor is its flat soffit. And clay channels in conjunc­ tion with hollow clay blocks (pots, tiles), for ex­ ample, can even create a uniform soffit. The filler elements are made from l i g htweight concrete, aerated concrete, expanded clay, pumice, etc. Two-way-span, hollow-block floors can also be fully prefabricated. The blocks are assembled on a flat surface and reinforcement is laid in the joints, which are subsequently concreted.

Brick arch floors Known by various names, this type of interme­ diate floor is still found in older buildings. It consists of slender steel beams with a filling of masonry in a shal low arch form. The thrusts from the arches are accommodated bay by bay and via the vertical loads. It was principally economic reasons that brought about the demise of this form of intermed iate floor in favour of the cheaper concrete slab.

a

Precast concrete intermediate floors

Like partly prefabricated floors, the fully prefab­ ricated floor usually requires no formwork and results in short construction times. Precast concrete slabs Sol i d concrete slabs can be prefabricated in sizes up to approx. 6.0 x 3 . 6 m and then l ifted into position on site. The joints between the individual slabs are filled with in situ concrete. When a stiffening diaphragm is required, it is necessary to weld the reinforcing bars together at the joints. If these slabs are laid on steel beams, a shear-resistant connection is achieved with bolts or shear studs in the joints, or an interlock between the slab edges. T-beam slabs A T-beam slab is an efficient system for long spans, especially if it is prestressed (preten­ sioned on the casting bed) . In order to exploit the material to the ful l , the neutral axis between the tension and compression zones should lie just within the slab (i.e. flange). The concrete industry can supply a range of standard sizes. To improve handling, the elements are usually precast with two beams per slab section (so­ called double-T un it) . Double-T floor units have two parallel beams set back from the longitudinal edges, whereas the beams of channel-section floor units are flush with the outside edges. Owing to trans­ port restrictions, the typical width is 2 .40 m . Aerated concrete slabs Prefabricated slabs made from aerated con­ crete are covered by D I N 4223. The d imen­ sions are based on fire protection, imposed load and column spacing req u i rements. The normal concrete cover of 1 0 mm to the steel mesh reinforcement is sufficient for fire resist­ ance class F 60. The maximum size is 8.0 x 0.75 m. When required to act as a stiffen­ ing diaphragm, approved products must be used, or a concrete topping added. The heat storage capacity is relatively low.

b

c

d

e

C 5.8

C 5.5 C 5.6

Timber intermediate floors

Concrete has now virtually taken over from tim­ ber as the preferred form of floor construction in housebuilding, a development that began in the 1 950s. However, the timber industry has now devised a number of systems using wood­ based products that can be assembled to form

C 5.7 C 5.8

Fair-face concrete soffit, Casa Vieja, Santiago, Chile, 2003, Mathias Klotz Ribbed intermediate floor with triangular grid, Yale Art Gallery, New Haven, USA, 1 958, Louis Kahn Glass-concrete slab, private house, Munich, Germany, 1 998, Karl + Probst Overview of timber intermediate floor forms a four-piece beam floor b floor of edge-fixed boards c cross-laminated timber floor d timber element floor e box-element floor f LVL ribbed timber floor

1 65

I ntermediate floors

Contrib. to sound insulation

Normal length of single span

One-way span

Two-way span

Cantilever options

Water vapour diffusion resistance

[kg/m"]

Total thermal resistance [m 2K!W]

[-]

[m]

1 20- 1 80

290-440

0.05-0.08

80/ 1 30

6-9

both directions

profile metal sheeting

1 20-320

270-375

0.05-0.08

;, 1 00000

2 - 5.8

one direction

ribbed concrete slab

1 87.5-500

1 80-430

0.03- 0.05

70/ 1 50

0

6-12

both directions

T-beam slab

350- 900

280-620

0.03-0.05

70/ 1 50

0

up to 1 4

hollow-core slab

1 20-400

2 1 0 -580

0.67-0.77

5/10

0

8 - 1 1 .5

two-way-span hollow-block floor

90-290

1 25 - 470

0 . 1 3 - 0.36

5/10

0

up to 6.5

Intermediate floor system

Standard structural depth

Weight

[mm]

Formwork required

Solid intermediate floors reinforced concrete flat slab composite slab with trapezoidal

Timber intermediate floors timber joist floor, solid filling

1 40- 200

1 20- 1 80

0.61 -0.71

2

0

4-6.5

one direction

floor of edge-fixed boards

1 20 - 2 1 6

85- 1 55

0.71 - 1 . 1 8

90/220

0

up to 6

one direction

timber box-element floor

1 20-320

40-90

0.46-0.74

5

6-10

one direction C 5.9

C 5.9 Comparison of intermediate floor constructions C 5 . 1 0 Erecting an LVL ribbed timber floor, refectory of M i litary Officers Training Academy, Dresden, Ger­ many, 1 998, Auer + Weber C 5. 1 1 Dome of Museum of Art H istory, Vienna, Austria, 1 891 , Gottfried Semper and Karl Freiherr von Hasenauer C 5 . 1 2 Grid ceiling, former offices of British Petroleum, Hamburg, Germany, 1 97 1 , Kraemer & Sieverts C 5 . 1 3 Ceiling of profiled timber boards, auditorium of the University of Albanez, Santiago, Chile, 2002, Jose Cruz Ovalle C 5 . 1 4 Perforated acoustic ceiling made from gypsum boards, police and fire brigade headquarters, Berlin, Germany, 2004, Sauerbruch H utton

accurate, efficient intermed iate floors. Besides the aspect of sustainabi lity, the advantages are simple working and the sorption behaviour's positive i nfluence on the interior c l imate. The d i sadvantages are timber's behaviour in fire and the low sound insulation. Solid timber floors can achieve the desired fire resistance with only a minimal i ncrease in depth over that required for structural purposes. The average cross-sectional loss in the event of a fire is about 0.8 mm/min. Fire protection req u i re­ ments can also be achieved with (fibrous) plas­ terboard. Non-rig id layers, or heavyweight layers in con­ junction with a floating screed and insulation (also loose fill) between the joists can improve the (airborne and impact) sound insulation. Improvements to details at supports and joints can also help to ensure that timber floors achieve the impact sound insulation necessary. Timber joist floors

Timber joist floors made from solid timber sec­ tions are economic for spans up to approx. 6.50 m ; longer spans req u i re g lued laminated timber members, trussing or a combination of solid timber and wood-based products. The beams are usually placed in pockets when supported on solid walls. But poor workman­ ship, defective masonry or ingress of water can lead to damage to the ends of the beams. Properly designed supports ensure ventilation around the beam ends and protect the under­ side of the beam (e.g. bearing pad of flexible bitumen sheetin g ) . Simple joist floors Solid timber joists at a spacing of 500-800 mm i n conjunction with 24-50 mm wooden floor­ boards nailed to the joists represent the sim­ plest form of one-way-span timber floor. Addi­ tional measures to improve airborne and impact sound insulation are advisable.

1 66

Isolated ceiling floors In this case the simple joist floor is provided with another layer of timber boards, wood­ based products or even hol low clay bricks between the joists. As this "isolating ceiling" has a d ifferent natural vibration frequency to that of the floorboards, it improves the impact sound i nsulation, and the airborne sound insu­ lation can be improved by adding a heavy­ weight loose fill material. Aerated concrete blocks can be added to some existing timber joist floors in order to improve their acoustic and thermal performance. Timber element intermediate floors

Together, industry and engineers have devel­ oped elements made from sol i d timber, g lued timber sections and wood-based products to produce a large selection of efficient flooring systems. It is not only the larger dimensions of glued components that justify the extra work req uired compared to solid timber - theirre­ duced shrinkage, less susceptibility to cracking and higher strengths are also major benefits. Four-piece beam floors Based on the four-piece beam principle (see p. 7 1 ) , these floors exhibit excellent strengths and little distortion. The soffit can remain exposed. Prefabricated flooring elements are available in sizes up to 1 2 m long and 600 mm wide (fi g . C 5 . 8 a) . Floors o f edge-fixed boards Prefabricated elements of machine-nailed or g lued boards on edge ( i . e . vertical) can be joined with dowels to form complete floors. This method of construction enables boards of lower quality to be used for loadbearing pur­ poses. Staggering the boards vertically results in longer spans for the same self-weight but does lead to a deeper overall construction (fig. C 5.8 b).

I ntermediate floors

Cross-laminated timber floors The maximum d imensions of the cross-banded, g lued plies are determined by the presses. Normal ly, elements up to 2.50 m wide and 25 m long are available. These two-way-span elements can also be used to solve complicat­ ed support situations over irregular plan shapes, and permit virtually any openings. Spans of up to 5 m are possible with the low structural depth of 80-1 20 mm (fi g . C 5 . 8 c ) . Timber element floors These planar elements for timber floors are pro­ duced by connecting glued timber beams and boards together at right-angles, which enables longer spans to be easily covered (fig C 5.8 d ) . The use of shear-resistant connections enables such floors to be used as stiffening d ia­ phragms. The voids can be filled with insulating material to improve the sound insulation. Box-element floors Each element consists of four boards glued together to create a box (rectangular) cross­ section. The individual box sections are then joined together with tongue and g roove joints to form complete floors (fig . C 5.8 e) . Structural depths of about 1 20--320 mm are necessary for spans of about 4-8 m. The elements are typi­ cally available in widths from 1 95 to 1 000 mm. The voids can be used as ventilation d ucts. Timber element floors with glulam beams Glued laminated timber beams are g lued i n parallel to a 1 .80 m wide 3-ply core plywood board. Structural depths of 3 1 0-830 mm and element lengths of up to about 25 m make this form of construction ideal for long-span roofs over sports halls etc. Perforated boards exhibit comparable load bearing characteristics and together with appropriate acoustic overlays can improve the room acoustics.

The long-term behaviour of the composite materials demands special attention in order to avoid damage at a later date caused by shrink­ age or creep. Edge-fixed floors with staggered boards achieve a bond effect between the con­ crete and the timber. Such floors achieve good stabil ity and sound insulation values.

Ceilings

The task of decorative ceilings in historical buildings was always to highlig ht the room, to g ive it prominence (fi g . C 5. 1 1 ) . Great attention was given to their design and the very highest manual skills were necessary for their realisa­ tion. Today, i n the majority of buildings the under­ side of an intermediate floor is usually merely the result of the necessary constructional measures. Technical progress has g iven build­ ing services more and more significance, wh ich has meant that ceilings have been g iven the mundane task of screening the space for services. A further requirement is to improve the room acoustics, depending on the geome­ try, surface finishes and functions of the rooms below. If the ceiling conceals a timber or steel structure, or ventilation ducts to other parts of the building, fire protection requirements must also be adhered to. Besides all the materials suitable for wall linings (e. g . wood-based products and boards with mineral b i nders) and those that are specifically intended for ceilings ( e . g . boards with mineral binders), semi-fi nished products, systems and special products for satisfying diverse other req u i rements are also available these days. According to their form of construction, we d i s­ tinguish between the following types of ceiling: · ·

L VL ribbed timber floors Boards of laminated veneer lumber (LVL) up to 23 m long and 1 .80 m wide are g lued to ribs of the same material to form effic ient elements suitable for relatively long spans. With a struc­ tural depth of just 1 70 mm, it is therefore possi­ ble to span more than 5 m (figs C 5.8 f and C 5. 1 0) . A suitable connection to the primary structure enables these floors to be used as stiffening d iaphragms. Cantilevers in the longi­ tudinal direction are possible, but openings must be planned very carefully. Timber-concrete composite construction Composite forms employing timber and con­ crete combine the advantages of the high stiff­ ness of concrete elements with the simple con­ necting methods of timber. A concrete topping can be bonded to joist, four-piece beam and edge-fixed floors. Special anchors screwed into the timber and left projecting i nto the con­ crete withstand the shear forces. This method is also ideal for strengthening existing timber floors, but is labour-intensive.

· • • · · ·

seamless ceilings ceilings of prefabricated panels boarded ceilings louvre ceilings grid ceilings cell ceilings pyramid ceilings stretch coverings

Seamless ceilings

Like wall linings, flat, smooth surfaces can be produced with boards containing a mineral binder. The boards are screwed to a framework fixed directly to or suspended below the under­ side of the intermediate floor. The joints are filled and the whole fin ished with paint to create a seamless soffit. HVAC services, pipes, cables and lighting are all easily incorporated. Furthermore, such cei lings contribute to the fire protection for the intermediate floor. Perforated panels influence the room acoustics. Many different boards are available with reg ular or irregular perforations which, together with a backing of i nsulating material, can influence the acoustics of the rooms below. If the joints between panels are carefully filled, the effect is C 5. 1 4

1 67

I ntermediate floors

C 5 . 1 5 Examples of acoustic ceiling forms a mineral-fibre tile b lightweight wood-wool tile c slotted tubular particleboard d mineral-fibre tile with plaster finish e lightweight acoustic tile with porous coating f wooden panel with plain edges and sound attenuating material g perforated metal pan h perforated gypsum panel (with plaster) i panel laminated with fibrous fleece and sound attenuating material C 5 . 1 6 Wire mesh ceiling, canteen of the Vitra Design Museum, Weil am Rhein, Germany, 1 989, Frank Gehry C 5. 1 7 Illuminated ceiling, trade fair stand, M i lan, Italy, 2003 C 5. 1 8 Life cycle assessment data for ceilings

Iv\/\/\/\/\/\/\ a

d

9

LY 1 1 1 1 1 1 1 1 1 1 1 1 1 1

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JDDD[

b

e

h

/\/\/\/\/\/\/\ �

/\/\/\/\/\/\/\

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c C 5. 1 5

one of a seamless ceiling, which is also suit­ able for complex geometries (fig C 5 . 1 4) . Rabitz ceilings This is a special type of seamless ceiling con­ struction named after its inventor, Karl Rabitz, a master bricklayer from Berli n . Accord ing to D I N 4 1 2 1 a Rabitz ceiling consists of suspend­ ed ribbed expanded metal to which a gypsum plaster is applied. If suspended elastically from the soffit, this type of the ceiling can comply with the high room acoustics req u i rements of concert halls (e.g. Philharmonie, Berl i n , 1 963, Hans Scharoun) . Ceilings of prefabricated panels

The advantage of prefabricated cei l i n g sys­ tems is that they can be supplied with the required surface finish, which speeds up instal­ lation and later enables easy access to the building services in the plenum above the ceil­ ing. Such systems i nclude coffered and tiled ceilings. Mineral-fibre and non-fibrous mineral-bonded tiles The mineral fibres obtained at high tempera­ tures are mixed with water and organic binders to form a pulp that is subseq uently rolled to form tiles. The normal thickness is 1 5 mm, but 20 mm and thicker tiles are also available. The tiles are supplied ready to install and can be obtained with a coloured coating or a metal, plastic or textile finish. The standard formats are multiples of 300 and 31 2.5 mm (fig. C 5.1 5a). Different edge forms enable the tiles to be fitted into exposed or concealed sections. The tiles are sensitive to moisture and can be obtained in both incombustible and not readily flamma­ ble qualities. Owing to their high degree of sound absorption, they are ideal for attenuatin g internal noise. Coatings applied subseq uently in situ can impair the acoustic properties, espe­ cially if applied incorrectly. Non-fibrous mineral-bonded tiles are similar to mineral-fibre tiles and are made from a mixture of perlite, vermiculite, clay, starch and cellulose. Calcium silicate insulating boards are also suit­ able for insulating against internal noise.

1 68

Metal ceilings Sheet steel and sheet aluminium can be formed into panels and suspended below the soffit of the i ntermediate floor. The underside of the ceiling can be closed or open. The range of metalworking techniq ues opens up a broad spectrum of various surface finishes such as perforated sheet metal, expanded metal, metal meshes and metal foams (e.g. made from alu­ minium). Sheet metal is often bent and folded to form pans. And with a layer of so-called acoustic fleece plus a perforated metal sur­ face, such pans can achieve a high degree of sound attenuation (fi g . C 5. 1 5 g) . Many pro­ ducts are coated on the exposed side. The sensitive coatings or metal surfaces must be protected prior to installation (e. g . by plastic film) . Wood-based products Wood-based products are often used as a backing for veneers, and cei l ings with wood veneers create a particularly high-qual ity impression. To improve the room acoustics, slotted tubular particleboard with a veneer or other type of fac i n g , elements assembled from battens, and perforated or slotted boards can be considered. Other products made from M D F boards have holes with varying d iameters routed in both sides. Such boards attenuate specific frequen­ cy bands and are therefore useful for lecture theatres and similar situations. Thanks to their low wei ght, wood-wool slabs are ideal as ceilings. They are frequently used to attenuate noise in structures with vehicular movements, e . g . mUlti-storey car parks. Their untreated surfaces have a rough look.

a n d soffit can improve the acoustics. Boards fixed on edge, i . e . vertically, at a large spacing are known as louvre ceilings. The larg­ er proportion of openings increases the effi­ ciency of the insulating material, but this can sti l l remain invisible from below, depending on the angle of view. Wooden boards Profiled boards of solid timber and wood­ based products can be used for ceilings. Open joints can prove effective acoustically. Slit edges to boards plus insulating materials above the cei l i n g improve the acoustics (figs C 5. 1 3, C 5. 1 5 e and C 5. 1 5 f) . Metal louvres Simple production and assembly methods for metal panels, which in comparison to pans have to be machined on two sides only, makes this type of ceiling particularly economical. Building services installed in the plenum above the ceiling remain accessible because the lou­ vres are easily detached from their special fix­ ings without tools. If perforated sheet metal is used, such ceilings can be employed as acoustic ceilings because the absorbent sur­ face area can be larger than that of a horizontal suspended ceiling. Grid ceilings

Open ceilings made from small modules fitted together in two directions without any visible joints are called grid ceilings. Metals and fibreboards are the standard mate­ rials for such cei l ings. Such ceil ings are perme­ able to l i g ht, air and sound (fi g . C 5 . 1 2 ) . Cell ceilings

Ceilings of synthetic materials Modern material-processing technologies have made it possible to add "invisible" perforations to certain plastic panels (e. g . PMMA) . These transparent or translucent panels can therefore attenuate interior noise. Boarded and louvre ceilings

Ceilings made from linear elements serve as a visual termination, but with the addition of sound insulating materials in the space between ceiling

I nteriors with a high level of noise, e . g . retail sales areas or production bays, are often fitted with cell ceilings (also known as egg-crate ceil­ ings) . These usually comprise closely spaced vertical slats running in several directions which create a larger sound-absorbent surface area than a flat or louvre ceiling with the same plan area. Systems open at the top and also those with closed bays are available. M ineral fi breboards or perforated metal pans are the usual materials.

I ntermediate floors

C 5. 1 6

C 5. 1 7

Pyramid ceilings

Stretch coverings

Large-format, three-dimensional ceiling ele­ ments are assembled from prefabricated parts to form pyramids which are supported on a load bearing grid. Again, thanks to their large surface area, these ceilings also improve the room acoustics. The complicated geometry restricts the choice of lights, air outlets, etc. to products that match the system.

Synthetic films and foils are suitable for span­ ning over long distances without the need for a supporting framework. Just a fraction of a milli­ metre thick, they can be joined together by welding to cover large areas. They can also be cut to fit unusual geometries and plan layouts. ETFE films are not read ily flammable (class B 1 ) and can be recycled. They are available in

many colours and with various degrees of gloss finish. These films are hyg ienic, antistatic and can also be used over wet interior areas (see "Synthetic materials", p 94) . Microperforations together with a backing of absorptive material improves the room acous­ tics. Furthermore, films with a high l ight perme­ ability can be combined with suitable lighting un its to create illuminated ceilings (fig . C 5. 1 7) .

Ceilings Layers • for origin of data see "Life cycle assessments", p . 1 00

PEI primary energy non-renewable [MJj

PEI primary energy renewable [MJj

GWP global warming [kg C02 eqj

ODP ozone depletion [kg R1 1 eqj

AP acidification [kg S02 eqj

EP eutrophication [kg PO.eqj

POCP summer smog [kg C2H.eqj

Wood-wool slab

1 10

381

-28

0

0.034

0.0029

0.0080

t:=J

c:=::=J

c:::==:::J

0.052

0.0044

0.0050

I===:J

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c=:J

0.020

0.00 1 3

0.0020

0

0

0

0.030

0.0034

0.0060

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c:==J

0.01 3

0.0014

0.0010

0

0

0

0. 1 2

0.0080

0.0 1 3

wood-wool slab with mineral binder, 25 mm framework of timber battens, 24 mm Pressed particleboard'

1 36

1 09

pressed particleboard with oak veneer, 1 9 mm framework of steel channels, galvanised, 40 mm mineral-fibre fleece, 40 mm

0

c::==

Calcium silicate board

56

calcium silicate board, 20 mm framework of steel channels, 50 mm

-

Fibrous plasterboard

97

fibrous plasterboard, 1 2.5 mm framework of timber battens, 24 mm

-

Plastered ceiling

56

gypsum plaster, 15 mm mat of bulrushes as background, 5 mm

-

Panel ceiling, steel

375

sheet steel pans, perforated, 0.88 mm steel beams, channel sections, 840 mm grid, 7.5 mm mineral fi breboard, 40 mm PE film facing

-5.8

1 .3 0

50 [=::::J

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3.3

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C 5. 1 8

1 69

Floors

C 6.1

The surface finishes and make-up of floors are crucial to the way an interior space is per­ ceived. They have to satisfy complex building performance tasks: sound i nsulation, thermal i nsulation, fire p rotection, moisture control, etc. The d iverse requirements placed on floors usu­ ally lead to a multi-layer structure. We distin­ guish between the following layers accord ing to their functions: Loadbearing layer The properties of the underlying structure, its form of construction and its position withi n the building influence the subsequent make-up of the floor (see " I ntermediate floors", p . 1 62 ) . Leve l l i n g layer Tolerances in the underlying structure that exceed those permitted by D I N 1 8 202 may render it necessary to i nclude a levelling layer, e . g . dry loose fi l l , cement screed, because the thicknesses of the overlying lay­ ers must be constant. Falls layer In wet interior areas falls drain the water to floor outlets. Screeds or insulating layers laid to falls on the underlying structure should be 1 .5 - 2 .0% in order to guarantee drainage even in the case of excessive tolerances and deformations. Waterproofing layer There are four d ifferent functions regarding p rotection against moisture (see " I nsulating and sealing", p . 1 44) : - waterproofing against moisture from the soil - waterproofi ng against non-hydrostatic pressure - waterproofi ng against external hydrostatic pressure - waterproofin g against internal hydrostatic pressure • I nsulating layer Thermal insulation in cantilevering u pper floors or ground floor slabs is certainly not unknown, but the i nsulation in floors is usually provided to reduce impact sou n d . The insula­ tion i n intermediate floors is achieved throug h a combination of the structural floor, cei l i n g and insulating materials between structural floor and screed. I n certain cases resilient floor coverings may satisfy the impact sound •

•

•

·

•

C 6.1 C 6.2

1 70

Roman floor mosaic Subfloor constructions a bonded screed b unbonded screed c floating screed d heated screed e raised floor f flooring-grade boards

•

·

requirements, provided it can be guaranteed that these floor coverings are not replaced at a later date by others with less effective acoustic characteristics. The density and depth of the load bearing layer have a major part to play in reducing airborne sound transmissions, and in multi­ layer constructions also measures beneath the structural floor (e.g. resi lient soffit finishes) or floating screeds. D I N 4 1 09 describes the minimum acoustic req uirements for intermedi­ ate floor constructions for the majority of building uses. In the case of cantilevering upper floors or ground floor slabs, additional insulating layers are required for thermal insulation (see " I nter­ mediate floors", p. 1 62). Separating layer Separating layers of strong paper or plastic sheeting ensure that the materials of the screed do not seep into the underlying insula­ tion and cause undesirable chemical reac­ tions between screed and underlying con­ struction Load-distributing layer In situ screeds or flooring-grade boards laid on the insulation function like a load-distribut­ ing slab and therefore protect the underlying insulation. Wearing layer The wearing layer or course (floor finish/cov­ ering) concludes the floor construction on the inside and, depending on requirements, must exhi bit d iverse qualities.

Screeds

This word, the origin of which is not entirely clear, stands for a thin layer in the floor con­ struction placed directly on the underlying structure, a separating layer or a layer of insu­ lation. The object of the screed is to achieve a predefined level, to provide a suitable sub­ strate for a floor covering, or to act as a wear­ ing course itself. The thickness of the screed should guarantee that the layer can carry the loads to be expected and that shrinkage, tem­ perature changes or concentrated loads do not cause cracking. D I N EN 1 3 81 3 covers screeds

Floors

and their designations; for example, CT- C 25 F 4 S 45 describes a cement screed (CT) with a compressive strength of 25 N /mm2 and a tensile bending strength of 4 N /mm2, S stands for floating screed, and 45 is the nomi­ nal thickness in millimetres (fi g . C 6.3). Screed forms

We d istinguish screeds according to their con­ struction as follows: • • · •

bonded unbonded floating heated: - screed - raised floor - flooring-grade boards

Bonded screed This is a screed laid on the load bearing layer such that a good bond develops between the two (fig. C 6.2 a) . This form is used in industrial buildings, ancillary rooms and for providing falls. The bond must g uarantee that deforma­ tions in the underlying structure do not lead to cracks in the screed, or to the screed becom­ ing detached from the substrate. Joints are necessary at penetrations such as columns and structural joints, and around the perimeter. Unbonded screed A separating layer of plastic sheeting or strong paper beneath the screed ensures that defor­ mations in the underlying structure do not have any detrimental effects on the floor finishes (fig. C 6.2 b) . This form of screed is often used for balconies or floors for heavy loads. Floating screed This type of screed is laid on the insulating layer and so remains movable on its substrate, hence the term "floating" (fi g . C 6.2 c) . The screed distributes all vertical and dynamic loads within its plane. In order to guarantee adequate tensile bending strength, minimum screed thicknesses are prescribed, which also depend on the properties of the insulating layer. As all the layers of the floor make-up must have a constant thickness, any pipes required must be laid in a bonded levelling layer ( i . e . no loose fills) . If several layers of insulation are requi red, the layer with the lowest compressive strength must be laid first ( i . e . at the bottom) . A layer of insulation reduces the airborne sound transmis­ sion by approx. 6 dB, the impact sound trans­ mission by 1 2-30 dB, depend i n g on thickness, and improves the thermal insulation. Heated screed This is the name g iven to a floor construction with heating p i pes laid in the screed. The thick­ ness of screed required is the nominal thick­ ness plus the d iameter of the pipes. Depending on the p lanned position of the p i pes, further pipe cover dimensions to D I N 1 8 560-2 may

also have to be complied with. The thermal stresses in the screed limit the bay size to approx. 40 m2 and the bay length-to-width ratio to max. 1 : 2. Larger rooms req u i re suitable joints, which usually have to continue through the floor covering as wel l . A n alternative is t o lay t h e pipes in the insulat­ ing layer, with a layer of mortar or suitable boards forming the loadbearing layer. In situa­ tions where the depth of the floor finishes must be minimised, e . g . in existing buildings, so­ called panel systems are being increasingly used; in these systems the hot water flows in slim, hol low panels of aluminium or plastic. Other methods of heating with air (hypocaust) or electrically heated plates cannot be d i s­ cussed withi n the scope of this book. Raised floor I n the case of b u i l d ings with extensive services or structural floors that contribute to heating and cooling and therefore restrict the ceilings that can be instal led, the services may need to be installed in the floor construction. Another advantage of raised floors is the easy replace­ ment and retrofitting of services; short utilisa­ tion cycles and frequently chang i n g conditions are the norm in computer centres, for i nstance. In such cases raised floors, platform floors and service ducts in the screed are useful. Joints and perimeter strips Deformations and d imensional changes to components due to drying out, temperature fluctuations and loads call for careful design of the junctions and joints for floating screeds. The architect is responsi ble for planning the layout and form of joints in screeds. We can d ivide screed joints i nto four d ifferent types: • • • •

Reinforcement The aim of providing reinforcement in a screed is to help prevent cracking; the reinforcement has no influence on the load-carrying capacity. Welded steel mesh reinforcement limits the propagation of cracks and may even prevent minor height variations. Reinforcement should not continue through joints. Fibre reinforcement is used to minimise shrinkage cracks. At present there are no binding obligations con­ cerning reinforcement.

a

b

c

isolating joints expansion joints perimeter joints dummy joints

Special profiles made from plastics or metal can be used to create such joints. Isolating joints between build ings of parts thereof must be formed in the screed so that structural movements do not lead to cracks in the screed or floor covering. Expansion joints divide the screed into bays according to the loads, flooring materials and room geometry in order to prevent cracks. Perimeter joints are necessary between screed and all vertical components. Perimeter joints using cork or other i nsulating materials ensure that no restraint forces ensue at the junctions with such components. If the floor covering requires a bed of mortar or adhesive, the mate­ rials of the perimeter joints should protrude to ensure that the joints are not accidentally filled. Dummy joints are i ncluded to prevent shrink­ age cracks forming as the screed sets. They are irrelevant for the final floor covering because they are closed off with synthetic resin prior to laying the floor covering.

d

e

C 6.2 1 71

Floors

Cl

.,

�

::l 0

"

Cl c:

Subfloor

Designation Normal to thickness DIN EN 1 3 81 3 [mm]

Density

[kg/m "]

Mortar screeds and other wet subfloors cement screed CT terrazzo, with cement binder CA calcium sulphate screed MA magnesite flooring flooring cement AS mastic asphalt synthetic resin coating SR

20-60 35-55 3 30-50 1 2 -20 1 2 - 35 20-30 2-10

2000 2000-2200 2 1 00 1 600- 2300 400- 1 600 21 00-2300 1 1 00

Dry subfloors fibrous plasterboard plasterboard

20-25 25

oriented strand board (OSB) clay tile subfloor

1 9-38 20- 50

::l

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.r= ., .0

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Permissible compressive strength [N/mm"]

Perm. tens. bending strength [N/mm"]

1 5- 55

2.5-3.5

1 5/35

0.0 1 2

A1

1 5-45 5 - 50

2.5-4.5 2.5-4.5

1 5/35 1 5/35

0.008 - 0.0 1 6 0.008

04

n.a.

5.5 - 7

1 000-1250 850-1 1 00

1 8 -30 6 3.5 6

600- 700 2000

1 .5-2.5 6 n.a.

6.2-7.5 6 1 .5-2.4 5.0 - 7. 1 2 . 6 5.8- 7.2 6 n.a.

Water vapour Coefficient diffusion of thermal resistance expansion [mm/mK] H

'': '" ., Building ;: materials class/ '" '" Combustibility ':; class

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n.a. n.a.

A1 A1 B1 ; B1 -C-s1 A2; B1 -C-s1 B1 ; B1 -C-s1

1 0/20 5/1 0

0.01 5 0.025-0.03

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1

As the thermal expansion of wood-based products is not critical i n relation to the shrinkage processes. the shrinkage behaviour in per cent per 1 % change in air humidity is given here. 2 The tensile bending strength depends on the direction of the paper facing; the values parallel to the fibres are given here (values perpendicular to fibres: 0.2-0.3). 3 The thickness of cement-bonded terrazzo i s 35-55 mm; the actual terrazzo layer is, however, only 20--30 mm. 4 With protection 5 With additional sheet metal heat conductors 6 Data provided by manufacturers C 6.3

Methods of laying We distinguish between trowelled and self-lev­ elling screeds. The former is spread over the surface before being levelled, compacted (with a screed board) and smoothed (floated ) . A self-levelling screed has a fluid consistency and finds its own level without the need for working with tools. Types of screed

Various binders can be used for producing screeds. Accordi ngly, DIN EN 1 3 8 1 3 d i stin­ guishes between the following types: ·

• · · •

cement screed calcium sulphate screed (anhydrite screed) magnesite flooring screed alternative: mastic asphalt synthetic resin screed

There are other types of screed that are not standardised, e . g . flooring-grade boards, raised floors, etc. After treating the surface, screeds can also be used directly as wearing surfaces, e . g . granolithic finish, flooring cement, terrazzo. Cement screed (CT) Cement screeds are the most common type. They are inexpensive and also suit many types of application, even externally. The grading of aggregates for cement mortar screeds is chosen according to the intended thickness. For example, 8 mm is the maximum grain size permitted for the standard thickness of approx. 40 mm. The screed should be as dense as possible and have a low water/ cement ratio (see "Building materials with min­ eral binders", p . 57) . Normally, cement screeds cannot accept any loads for the first seven

1 72

days after laying; they need relatively long dry­ ing times because they can dry out only through their u pper surfaces. If they dry too q uickly, there is the risk of distorting the edges, which is why these screeds must be covered with plastic sheeting to control the dryin g proc­ ess. The basic rule of thumb is: the longer the drying process, the lower is the risk of shrink­ age cracks. The moisture content of a cement screed must be checked before laying sensi­ tive floor finishes because there is a maximum permissible moisture content for floor cover­ ings, which must be adhered to. Special b ind­ ers permit shorter drying times. Cement screeds can only be laid in enclosed rooms at temperatures > 5°C. Granol ithic finish Wearing courses for industrial floors are fre­ q uently made from a cement screed with aggregates of metal, stone or emery or carbo­ rundum powder. These floors achieve com­ pressive strengths of up to 65 N /mm2. Terrazzo A cement screed finish made up of white cement, white and coloured aggregates (e.g. marble, porphyry, tuff) and pigments is known as terrazzo, which requires no further floor cov­ eri n g . The high cement content of the terrazzo mortar leads to severe shrinkage behaviour, which is why terrazzo floors are d ivided into bays measuring about 2 x 2 m . The self-weight of the approx. 20-30 mm thick layer is approx. 48 kg /m2. Terrazzo must be ground at least twice and is therefore a costly floor covering, but on the other hand very durable (fig . C 6.4 a) .

Calcium sulphate screed (CA) Screeds based on calcium sulphate were pre­ viously known as anhydrite screeds. Calcium sulphate screeds must be laid immediately after mixin g . They can accept loads five days after laying. Laying at temperatures < 5°C is not permitted. Owing to the slower curing proc­ ess in comparison to cement screeds, they achieve h i g h strengths and exhibit l ittle shrink­ age. These screeds are sensitive to moisture and therefore cannot be used outdoors, nor i n wet interior areas, even with falls a n d floor out­ lets. Additional waterproofing measures are necessary when laying these screeds on floors in d i rect contact with the soi l . Calcium sulphate screeds are often used in the form of self-levelling screeds. They can be laid without joints, even large areas, are easily and q uickly processed with site plant, and do not need to be compacted or floated. The surface can be ground and then the screed req u i res no further floor covering. Fig. C 6.4 d shows such a screed with a clay brick aggregate. Magnesite flooring (MA) Screeds can also be produced from a mixture of magnesium oxides and magnesium chloride solutions p l us further aggregates such as sand and pumice, but also organic aggregates, e . g . sawdust, cork, rubber, textile fibres a n d paper powder. The fast reaction time calls for careful work on site. Magnesite flooring is suitable for seamless, heavily loaded, bonded screeds (strengths up to 80 N/mm2) covering large areas, as are often necessary in industrial buildings. The temperature during laying must be > 5°C. Magnesite flooring can accept foot traffic after just two days, and is ready for its full loading after five days. However, it is not water-

.£

Floors

proof and therefore cannot be used for wet interior areas, nor outside. It can be protected by linseed oil and wax. Theoretically, magnes­ ite flooring can be returned to the raw materials life cycle, but in practice it is disposed of in landfill sites along with other mineral building materials. Flooring cement Densities < 1 600 kg / m3 can be achieved by adding aggregates such as sawdust to magne­ site flooring. The weight for a thickness of 1 220 mm is about 2 2 - 36 kg / m2 . The properties of flooring cements such as thermal conductivi­ ty, drying time and strength can be influenced by the mixing ratio. Despite their many advan­ tages, flooring cements are hardly used at present. They are elastic, feel warm underfoot, insulate against sound and the hardwearing surface can be used as a wearing course in itself. Coloured pigments can be added with lit­ tle effort. Mastic asphalt (AS) Bitumen is suitable as a binder for fine-grain aggregates such as stone dust, sand , chip­ pings and - possibly - gravel, which i n contrast to other aggregates must be dry before being added to the mixer. The binder content is about 8% instead of the approx. 1 6% for cement screeds. The climatic, chemical and mechanical resist­ ances depend on the particular mix, which must take into account the uti lisation plus ther­ mal and compressive loads. Mastic asphalt retains its thermoplastic behaviour even after laying, which means that heavy concentrated loads may leave imprints in the floor. The clas­ sification of mastic asphalt floors is therefore carried out according to hardness grades, measured by the penetration depth of a defined stamp . The applications are assigned to four hardness grades: G E 1 0 and GE 1 5 for heated rooms, GE 1 5 and G E 40 for unheated rooms, and GE40 and G E 1 00 for rooms with low tempera­ tures. When laid on insulating materials, mini­ mum requirements regarding compressive strength therefore apply. The laying temperature of approx. 250°C plac­ es considerable thermal demands on the underlying insulation. M i neral fibres, cork, perl­ ite, cellular glass and bitumen-impregnated wood-fibre insulating board are suitable insulat­ ing materials. Around the perimeter there is the risk of the impact sound insulation yieldi n g , so it is advisable to strengthen the edges to pre­ vent deformation in this zone. This is normally achieved by omitting the impact sound insula­ tion along the edges. The advantage of mastic asphalt for work on site is that it does not require any mechanical compaction and can be laid regardless of the weather. It can accept its fu ll load after just 2 -3 hours, is ready for laying further floor fin­ ishes once it has cooled, and requires no joints. Mastic asphalt is watertight, vapourtight,

not sensitive to water and not readily flammable (class B 1 ) . The optional addition of graphite powder affects the electrical conductivity of the asphalt and hence prevents electrostatic charges. Mastic asphalt achieves good sound insulation values and can be fully recycled. In contrast to popular opinion, mastic asphalt has no hazard­ ous i mpact on the environment, neither during laying nor in use (fig. C 6.4 c). Synthetic resin screed (SR) Screeds that use a synthetic resin as the binder and a quartz aggregate are suitable for heavily loaded industrial floors. Screeds with epoxy, polyester, methacrylate or polyurethane resins are laid in thicknesses of 5-1 0 mm. The aggre­ gates are quartz grains, but coloured pigments can also be added. Synthetic resin screeds can be ful ly loaded after seven days. They are practically vapour­ tight and easy to clean, although the rough sur­ face does require special cleaning equipment. M ixes with larger grains may satisfy impact sound insulation requirements. Electrical con­ ductivity can be achieved by adding graphite. The applications include production areas, abattoirs, laboratories, etc. Synthetic resin screeds can be recycled, but in practice sepa­ rating this thin layer from its substrate is uneco­ nomic (fig . C 6 . 4 e ) . Loam screed Loam screeds and tamped loam floors are among the oldest forms of screed and can be used without any further floor covering. Owing to their good moisture regulation properties, they are suitable for roof spaces, basements and rooms for storing foods and drinks. They are produced by mixing loam, water and organic aggregates such as wood c h i ppings, chaff and cow hair and then compacting this. The comparatively low strengths can be improved by adding cow blood and ash to the uppermost layer. Flooring-grade boards Various types of board are available for pro­ d ucing a floor finish in dry construction irre­ spective of the weather conditions. The advan­ tage is that no drying time is necessary. The boards can be used immediately after laying and any further floor finishes added immed iate­ ly. If the wearing layer is not g lued to the sub­ strate, the boards can be fed back into the raw materials l ife cycle. The boards are laid with staggered joints on, for example, loose fill or insulating materials, but can also be laid direct­ ly on existing floor coverings. Owin g to their minimal thickness, they are suitable for improv­ ing building performance characteristics and for upgrading old floors. Flooring-grade boards can increase the sound insulation of suspend­ ed floors by up to 28 dB. F i g . C 6.3 l ists further properties.

C 6.4

C 6.3 C 6.4

Physical parameters of subfloors Screeds and subfloors a terrazzo b flooring cement c mastic asphalt as wearing course d calcium sulphate screed with clay brick aggregate e synthetic resin screed f cement screed

1 73

Floors

Screeds and subfloors Layers • for origin of data see "Life cycle assessments", p. 1 00

PEI primary energy non-renewable [MJ]

PEI primary energy renewable [MJ]

GWP global warming [kg C02eq]

oop

ozone depletion [kg R 1 1 eq]

AP acidification [kg S02 eq]

EP eutrophi­ cation [kg PO, eq]

pocP summer smog [kg C2H, eq]

203

3.8

18

o

0.076

0.0073

0.0070

C======::JI

IC======::J

0.026

0.001 8

Mortar screeds and wet subfloors cement screed cement screed (CT 20-8 50), 50 mm building paper, 0.2 mm mineral-fibre insulation, 20/1 5 mm calcium sulphate screed

71

2.2

calcium sulphate screed (CA 20-8 50). 50 mm building paper, 0.2 mm mineral-fibre insulation, 20/1 5 mm mastic asphalt

5.8

o

=

443

5.1

11

o

o

0.064

mastic asphalt, 25 mm building paper, 0.2 mm coconut board, 10 mm magnesite flooring

21 1

3.6

14

0.001 0

o

0.038

magnesite flooring (MA CT C 50-V 25 F). 25 mm mineral-fibre insulation 25/20 mm

0.0069

0.0 1 3

==,

=== :::::::1 lC

0.0035

0.01 3

=

Dry subfloors clay tiles clay tiles, tile adhesive, 20 mm mineral-fibre insulation 25/20 mm fibrous plasterboard fibrous plasterboard, 2 layers, 20 mm mineral-fibre insulation, 25/20 mm particleboard* particleboard (P1 ) , glued, 19 mm mineral-fibre insulation, 20/1 5 mm polyethylene fleece (PE). 1 mm C 6.5

The following materials are suitable: · • • · •

particleboards wood-fibre composite boards plasterboards fibrous plasterboards composite boards of gypsum and i nsulating materials

Particleboards Flooring-grade particle boards have tongue and g roove joints on all sides, which ensure tight joints after being g lued and a flush upper sur­ face. Thicknesses of 1 0 to 70 mm are possible, with the minimum thickness for normal imposed loads being 1 9-22 mm. Laying is covered by DIN 68 77 1 . The boards can be laid o n existin g floors, battens or a d r y fill, e . g . perlite . The applications for particle boards bonded with synthetic resin are limited to rooms with low moisture loads. But the heavier, cement­ bonded boards are resistant to the effects of moisture and are also not readily flammable (class B 2 ) . Vapourtight sheeting should not b e used when laying the boards over timber joist floors because the sheeting hinders the vapour d iffu­ sion through the construction, which can lead to rotting of the timber. Plasterboards and fibrous plasterboards Three layers glued together with rebated joints

1 74

and generous overlaps are available for use as flooring. The board thickness lies between 20 and 25 mm. The advantages of these boards compared to particleboards are their better d imensional stabil ity, better sound insulation values (owing to the higher self-weight) and the building materials class A2 rating (incombusti­ ble) . They are laid in a similar way to particle­ boards and are frequently bonded d i rectly to a layer of insu lation. Clay tile subfloor Clay tiles with a facing qual ity and tongue and g roove joints are avai lable as 20 mm thick sol i d or a s 40 - 50 mm thick slotted versions. They are glued in place floating on a layer of insulation. The thicker tiles are intended for lay­ ing in a thick bed of tile adhesive or sand. Owing to their temperature and moisture regu­ lating properties, they are especially suitable for storage rooms. Sprun g floors For some special applications such as sports and dance halls, wooden floorboards are sup­ ported elastically on the underlying construc­ tion. We d istinguish between floors supported over their full area on orthogonal layers of boards, and floors supported at individual points on foamed materials.

Floor coverings

The materia l , appearance, texture and colour of the floor covering have a considerable influ­ ence on our perception of an i nterior. Besides functional considerations, the aesthetic con­ cept determines the choice of floor finish. Appearance and sound i nsulation also contrib­ ute substantially to our subjective evaluation of an agreeable interior atmosphere. Selecting the visual appearance of a floor cov­ ering can be based on various concepts. For example, the idea could be to create the illu­ sion of walls, floor and ceiling cast from one mou l d , but it could equally wel l involve a stark contrast between materials and/or colours. It is frequently the case that walls and ceiling form a neutral background for the finishes and fit­ tings of the user. U niform floor coverings can emphasise relationships between different areas, e . g . between internal and external zones, and different coverings within a room can define d ifferent functional zones. The treat­ ment of the surface demands particular atten­ tion. In contrast to a matt, rugged surface fin­ ish, the appearance of a gloss finish can change with the angle of incident daylight. A huge range of materials, products and prod­ uct variations (colour, q uality, texture and other characteristics) is avai lable to satisfy the multi­ tude of requirements (fig . C 6.7). In addition to the normal parameters for choosing a building

Floors

I II III

= = =

Cement screeds • granolithic . terrazzo

particularly warm underfoot adequately warm underfoot no longer adequately warm underfoot

clay brk. agg. scd.

I n contrast to the heat penetration factor, the thermal energy lost from a surface at a temper­ ature of 33°C d uring 1 or 1 0 min was hitherto used as the standard ( D I N 52 6 1 4) . But whether warm underfoot or not is a - to a certain extent subjective - factor of the overall comfort of an interior that cannot be entirely covered by a physically quantifiable figure. I n the case of floor coverings that are perceived as particular­ ly warm underfoot, a feeling of comfort is still possible even when the temperature of the inte­ rior air is 1 -2°C lower.

C 6.6 C 6.5 C 6.6 C 6.7

Life cycle assessment data for screeds and subfloors Marble floor, Santa Maria della Salute, Venice, Italy, 1 683, Baldassare Longhena Systematic classification of floor coverings

material, there are other requirements specific to floors. Building design The first parameters concern the existin g build­ ing or the specification. Self-weight and depth of construction must be compatible with the compressive strength and hence the load-car­ rying capacity of the underlying structure and the framework cond itions of the interior, e . g . levels of adjoining floors. The underlying construction is also important. Underfloor heating and raised floors are not compatible with every type of floor covering. I n order to prevent entrapped moisture in con­ crete slabs and screeds causing damage, flooring-layers must check the residual mois­ ture content of the substrate prior to laying floor finishes. Building performance Moisture control, sound i nsulation and thermal insulation requirements may restrict the choice of floor covering. Fig. C 6.20 (see p . 1 84) shows comparative values. Heat conduction, perceived temperature Loss of heat from the human body due to con­ tact with a floor finish leads to the floor finish feeling cold. We classify floor coverings according to the following system :

Electrostatic behaviour Electrical charges can accumulate in a person as he or she walks across an insu lating floor coveri n g , and these can lead to unpleasant discharges upon touching earthed metal objects such as door handles, safety barriers, even computers. Humidity, footwear material and clothes influence this process. Sensitive electronic equipment can be damaged by the ensuing h i g h voltages. D I N 54 346 d ivides floor coverings into three classes accordi n g to their electrostatic proper­ ties

Class 1 covers the so-called antistatic floor coverings; i . e . the charge that builds up i n persons walking across such floors is max. 2.0 kV. This is the specification for all rooms with electronic equipment (also residential accommodation) . • Class 2 is necessary to prevent damage in rooms with sensitive equipment. Suitable floor coverings are designated as conductive. Class 3 is achieved by the especially conduc­ tive floor coverings essential for safety rea­ sons in operating theatres, research estab­ l ishments and production faci l ities (protection for persons and equipment, explosion protec­ tion).

Finished subfloors

synthetic resin coating

natural stone Stone

Non-slip properties Germany's employers' liability insurance asso­ ciations specify minimum req u i rements for floor coverings for safety reasons (publication BGR 1 81 ) . The parameters for this are the surface texture (classes R 9-R 1 3) and the liquid d is­ placement factor (classes V 2 -V 1 0) .

cement-bonded recon. stone bitumen-bonded tiles

Ceramics
.�

> o u

8

clay bricks stoneware earthenware split-face blocks eng. bricks terracotta

glass mosaic tiles

-=

laminated glass Glass and metal

embossed sheet metal etc. open mesh floor

Wood and wood­ based products

floorboards wood-block fir. end-grain wood­ blk. parquet squares real wood lam. aSB plywood

•

Usage The suitabil ity of floor coverings for certain uses are regulated by hygiene, industrial safety (non-sl i p ) , electrical conductivity and many other aspects.

mastic asphalt tamped loam

·

In practice it is vital to ensure that the floor cov­ erings are attached to conductive undercoats with suitable adhesives. Copper strips incorpo­ rated in the floor (and connected to a suitable earthing system) g uarantee that any voltages that may build up can be discharged safely.

flooring cement

Laminated floor coverings


.� > o u

Made from natural materials

o

o -=

C � 'ii) Ql 0:


Made from synthe­ tic materials

Natural fibres

c

laminated flooring

rubber cork rubber linoleum leather

PVC

sisal coconut jute seaweed bulrushes raffia

.� 6 u

o

o -=

Synthetic fibres

C 6.7

1 75

Floors

For example, floor coverings in industrial kitch­ ens must comply with the requirements of R 1 3 and V4: class R 1 3 means that a surface inclined at an angle > 35° is not slippery for persons under normal conditions, and V4 means that a volume of liquid equal to 4 cm3/ dm2 can be accommodated by the surface structure without forming a continuous film of moisture, There are three classes (A-C) for barefoot areas (e,g, swimming pools) ; class C is the highest safety standard , Chair castors Product data sheets on floor coverings always contain details of the product's suitability for chair castors in offices, The castor and floor covering materials must be compatible, Castor type W is soft and therefore suitable for hard floor coverings, whereas type H is hard and better for soft floor coverings, Interior climate Floor coverings can have a serious influence on the interior climate, The materials and adhe­ sives plus cleaning and care products must be chosen carefully in order to rule out - as far as possible - any risk of hazardous substances, Sustainability Floor coverings are subject to high mechanical loads, Accordingly, wearing characteristics play a key role in their selection, There is a D I N classification for contract ratings for various groups of coverings (fig, C 6,20) , Floor coverings should not change colour when exposed to d i rect sunlight. Changes in the material structure due to mechanical loads and moisture or temperature fluctuations can cause fissures (wood-block flooring) or tension cracks, Owing to the necessity of regular care over the entire lifetime of a floor covering, the cost of upkeep of some floor finishes is higher than the capital outlay,

Properties Owin g to their good wearing resistance, stone Natural and reconstituted stone, ceramics, floor coverings are always first choice if, despite glass, metal, wood and wood-based products heavy loads, a long service life can be antici­ make up the group of hard floor coverings, pated to offset their high cost. The surface The large range of man-made tiles and flags treatment, which influences abrasion and non­ can be differentiated accord ing to the binder slip characteristics, is very important (figs used: cement, synthetic resin, bitumen and C 6 , 9 a and b), The spectrum ranges from clay (ceramics) , - porous stone types with rough surfaces (e,g, Flags and tiles made from materials with a min­ sandstone) to smooth, polished marble or gran­ eral binder can be laid in a 1 5-20 mm mortar ite, The suitabil ity of a type of stone and its sur­ bed (thick-bed method) when used as a floor face treatment for a certain application must be coverin g , There should be no excess moisture verified by standardised ( D I N) test certificates, in the underlying components because this in Sedimentary rocks with porous, unsealed sur­ combination with the alkaline mortar can dis­ faces are vulnerable to fluids such as fats, solve some constituents in stone and cause wine, etc, And acidic substances (e,g, vinegar) unattractive discoloration, When using the thin­ can cause chemical reactions that lead to d is­ coloration, It is advisable to request the appro­ bed laying method, the flags and tiles used must exhi bit better d i mensional stability and the priate test certificates, substrate must be more accurate, which is usu­ Some types of stone such as quartzite, sand­ ally achieved with a levelling layer, This method stone and gneiss have high a coefficient of is also suitable for laying flooring-grade thermal expansion, All types of natural stone belong to building materials class A 1 (incom­ boards, The choice of mortar or tile adhesive depends on the use of the area, the substrate bustible), Stone floor coverings are perceived and the loads anticipated, as cold underfoot. Owing to their high thermal conductivity and heat storage capacity, stone Joints is a good choice in conjunction with underfloor The grouting of joints between stone or ceramic heatin g , Stone floor coverings without an insu­ flags and tiles with a fine cement mortar should lating layer make no contribution to impact not be carried out too soon; a drying time of 7sound insulation, 1 4 days should be allowed for, Some types of stone susceptible to discoloration req u i re a Planning advice rapid-hardening mortar, Thin (approx, 1 0 mm) stone tiles ground flat The size, pattern and direction of joints are criti­ can be laid l i ke ceramic tiles in a thin bed of cal for the final appearance of a hard floor cov­ adhesive, However, flags 20-50 mm thick in eri n g , A plan that also takes into account the formats up to 300 x 600 mm are more common, junctions with vertical components is vital, and these require a mortar bed, The low tensile especially for non-orthogonal layouts, strength of stone means that the thickness increases with the plan size , As the production Natural stone of larger formats results in more wastage, the The variety of d ifferent types of stone available costs increase disproportionately, Cement mor­ is enormous, As they can exhi bit d ifferent tex­ tar plus quartz sand is used for filling the joints, tures and colours depending on their orig i n , The colour of the joints can be matched to that even thoug h their composition is identical, of the stone floor covering by mixing in stone stone types are often marketed with particular dust or pigments, product names, which complicates any review, Some cleaning products attack some of the Hard floor coverings

C 6,8

C 6,9

a

b

c

d C 6,8

1 76

Tile and flag layouts (examples) a crazy paving b random stretcher pattern c alternating grid and stretcher pattern d grid pattern Examples of hard floor coverings a natural stone (coarse) b natural stone (fine, dressed) c reconstituted stone d stone with synthetic resin binder e mastic asphalt tiles f engineering bricks g ceramic tiles h glass mosaic tiles

Floors

constituents in stone (e.g. l ime) . It is therefore essential to follow the recommendations of the suppliers. Special attention must be paid to a stone's chemical resistance to acids and dis­ solved salts when the stone is being used for external and entrance zones. Flags and payers with a cement binder

Precasting plants fabricate flags and pavers (reconstituted stone) from large blocks, which are then sawn and ground after curing (fi g . C 6.9 c) . Cement is used a s t h e binder. The great variety of products is due to the large selection of aggregates available, e . g . stone, gravel , pigments, glass, etc. The improper use of glass aggregates has led to problems in the past. Besides the so-called single layer method, two­ layer elements can be manufactured by press­ ing, and this permits the use of a surface finish with a more expensive aggregate. Surface treatments and properties are similar to those of concrete, or rather the aggregates. The standard formats are 250 x 250 x 22 mm, 300 x 300 x 27 mm and 500 x 500 x 50 mm; larger, custom formats are also possible. These flags and pavers are usually laid in a thick bed of mortar. They represent a less expensive alternative to natural stone products and are also suitable for use in conjunction with under­ floor heating. Flags with a synthetic resin binder

These products are made from synthetic resins and a stone granu late. The 1 5 - 20 mm thick flags are cut from large blocks of cured materi­ al and the top surface is pol ished afterwards. They are simi lar in appearance to the reconsti­ tuted stone flags, some even look remarkably like natural stone (especially the conglomerate rocks) (fig . C 6.9 d ) . The properties of the bind­ er enable thinner flags to be produced than with reconstituted stone. Large formats up to 1 800 x 3800 mm are available, but also spe­ cially formed components for washing areas etc. The surface is less hardwearing than com­ parable natural stone. Most of these products are not frost-resistant and belong to building materials class B1 (not read ily flammable) . These represent a less expensive alternative to natural stone products and have almost identi­ cal properties, but a lower chemical resistance to acids, stain removers and similar products. Tiles with a bitumen binder

Mastic asphalt tiles are available in simi lar for­ mats to tiles made with a cement binder. The mixing ratios can be adjusted so that the prop­ erties are simi lar to those of a mastic asphalt floor (see p. 1 73) . The range on offer includes three types of pressed asphalt tiles: standard, mineral oils- and acid-resistant, and terrazzo asphalt tiles, which combine the properties of reconstituted stone and mastic asphalt. Owing to their good resistance to chemical effects, mineral oils, facts, petrol , etc. , mastic asphalt tiles are especially suitable for trade fair and

industrial buildings. A mastic asphalt floor cov­ ering requires protection against rising damp. They are weather- and frost-resistant (fi g . C 6 . g e ) . Ceramic products

The group of ceramic floor coverings includes stoneware and earthenware products, ceramic split-face blocks, engineering bricks (fi g . C 6.9f) and brick slips. Fine ceramic tiles The standard sizes are 1 00 x 1 00 mm to 300 x 900 mm, but larger, custom sizes are also possible, as wel l as stoneware and g lass products as small as 1 0 x 1 0 mm. The non-slip characteristics of earthenware products are only limited , and they are not frost-resistant. Stoneware products, on the other han d , have a denser body ( i . e . clay product without g laze) , which even without a g laze are also suitable as floor coverings. Glazes are divided into four wearing groups,. However, grains of sand adhering to the soles of shoes can scratch all glazed surfaces, which is why they are not suitable for heavily traf­ ficked areas. Coarse ceramic floor coverings Split-face blocks are produced by extrusion. The standard formats are 240 x 1 1 5 mm and 1 94 x 94 mm. Split-face slips are narrower, e . g , 240 x 52 mm o r 240 x 7 3 mm. Engineering bricks for floors are manufactured by pressing. Besides square formats based on the 300 mm module, there are also many products that do not correspond to the modular d i mensions. Properties and planning advice Ceramic floor coverings are very hardwearin g a n d long-lastin g . They are incombusti ble (building materials class A 1 ) , thermally stable, exhibit a good heat storage capacity and do not rot. Frost-resistant products must be select­ ed for external applications. Both the thick- and thin-bed methods of laying can be used. Ceramic floor finishes are also ideal for use in conjunction with underfloor heating. Design options Besides the surface finish of the tile itself, the network of joints presents another significant design option. A plan of the tile layout should be produced in order to coordinate layout, cuttin g and fixtures, and to help avoid awkward small cuts, which are a disadvantage both visual ly and technical­ ly. The tiles can be laid in diagonal or orthogo­ nal patterns, with contrasting strips, edges, arrangements and many more ideas. I nd ividual designs and patterns are possible with l ittle effort.

h

C 6.9 1 77

Floors

r---f-r---r---r---r----

I a

b

Floor coverings of wood and wood- based products

c

• • •

Wooden floorboards were the principal cover­ ing to timber joist floors until wel l i nto the 20th century. The softwoods used in most cases are less hardwearing than hardwoods with their very durable surfaces. All wooden floors feel warm underfoot, exhi bit good hygiene proper­ ties and require little maintenance. For details of the advantages of this renewable raw material, please refer to "Wood and wood­ based products", p. 75. Design options

Owing to the multitude of possibilities, wooden floor coverings can create a vast ran g e of dif­ ferent interior atmospheres. Species of wood, formats, method of laying and surface treat­ ment are the parameters that affect the appear­ ance of a wooden floor. Species of wood The appearance of the floor covering is essen­ tially determined by the species of wood (see "Wood and wood-based products", p. 69) . When choosing wood for parquet flooring, for instance, it is the texture or grain that is critical. For example, the term "exquisite" in oak par­ quet flooring describes equivalent pieces of wood that have been very carefully selected, whereas "rustic" can contain vigorous colour variations, and "standard" l ies somewhere between the two. Samples should be request­ ed to illustrate the d ifference in the overall appearance of a floor coveri n g . Origin From the ecological viewpoint, indigenous spe­ cies should be preferred over exotic varieties. The FSC (Forest Stewardship Council) certifi­ cate - also available for products from over­ seas - guarantees that the rules of sustainable forestry are upheld. Formats Wooden floor coverings can be d ivided into the following groups depending on the proportion of solid timber and the sizes of the components:

• •

I

I

I

d

floorboards wood-block flooring mosaic parquet real wood parquet laminate end-grain wood-block flooring

Laminated floors do not include any sol id tim­ ber and are therefore dealt with on p. 1 79.

Floorboards Floorboards are cut from solid timber and are usually laid in lengths to match the width of the room. Lengths up to 6 m and widths up to 350 mm are available (fi g . C 6. 1 2 a) . When lay­ ing on battens and strips of insulation, a screed is not essential. Floorboards are not the same as the so-called rustic-look floorboards availa­ ble these days, which are made from a multi­ layer wood-based product and therefore fall into the category of real wood parquet laminate (see below) . Solid wood-block flooring Sol i d wood-block flooring is max. 22 mm thick and available in squares or separate blocks. The blocks have a groove on all sides into which loose tongues are g lued to join the strips to form a complete floor. Some versions are available with alternating tongue and groove joints. The squares (or "ti les") are blocks sup­ plied already g lued together into larger for­ mats, up to 1 x 1 m depending on the planned pattern. D ifferent species of wood can be com­ bined within the squares to form complex pat­ terns (figs C 6. 1 2 c and d ) . Wood-block flooring is g lued to flat substrates over its full area; but on a floating subfloor of timber or wood-based products, the flooring is secret-nailed in the joints. The laying options are almost endless: ship's deck, brick half-bond, straight basket and d iagonal basket form orthogonal patterns. The d imensional tolerances of building components can lead to acute-angled cuts with these floor finishes. Herringbone, double herringbone and chevron patterns are laid at an angle of 45° to the enclosing walls. The patterns used with wood-block squares include Bordeaux, Monti-

e

cello and Versailles with and without borders and/or traml ines. 10 mm solid wood-block flooring The thinner material is an alternative to solid wood-block flooring and is suitable for refur­ bishment work or as a substitute for floor cover­ ings of similar thickness (ceramic tiles) . A fab­ ric or paper mesh backing holds together the 1 0 mm thick blocks to ease the full-bond gluing to the substrate. The finished floor cannot be distinguished from standard wood-block flooring.

Mosaic parquet, block-an-edge parquet Smaller blocks of wood 8 mm thick correspond in principle to the 1 0 mm solid wood-block floorin g . The length of the blocks is l imited to max. 1 65 mm. The squares supplied on a paper mesh backing consist of, for example, four bays each comprising five blocks, which form the characteristic basket weave of five-fin­ ger pattern. Block-on-edge parquet is very hardwearing and consists of a mosaic of blocks on edge to form a wearing course 1 824 mm thick (fi gs C 6. 1 2 e and f) . Real wood parquet laminate flooring I n order to avoid shrinkage of the wood and open joints in the flooring, mUlti-layer assem­ b l ies - mostly three cross-banded plies - of wood-block flooring are available. Both individ­ ual blocks and also larger elements (to simpl ify

b

1 78

C 6.10

Floors

Wooden flooring format C 6. 1 0 Examples of wood-block flooring a ship's deck b brick half-bond c herring bone d square basket e diagonal basket f parquet floor squares C 6.1 1 Dimensions of wooden floor coverings C 6. 1 2 Types of parquet flooring a ship's deck b herringbone c parquet floor squares d marquetry parquet e mosaic parquet, square basket pattern f mosaic parquet, parallel pattern g end-grain wood-block h bamboo parquet, ship's deck pattern

Thickness of wearing course [mm]

Floorboards

( solid ) wood-block flooring

1 4 -22

Thickness of material [mm]

Visible format, max. [mm]

1 5.5-40

up to 6000 x 1 75

1 4 -22

up to 600 x SO

mosaic parquet

S

S

up to 1 65 x 25

1 0 mm solid wood-block flooring

10

10

n.a.

block-on-edge parquet

1 S -24

1 S-24

1 30-1 60 x S

end-grain wood-block flooring

22-60

22-60

1 3S x 69 650 x 50, 300 -1 200 x 60

real wood parquet laminate flooring

3-S

7 - 26

rustic-look floorboards

3-S

7 - 26

oriented strand board

1 0 -1 2

10-12

2500 x 1 250

,;: 2

7-10

1 208 x 1 94

veneered boards

up to 3000 x 200

C 6.1 1

laying ) , comprising several blocks to form a wearing course, are available. The wearing course consists of hardwood at least 2 mm thick, the underlying plies softwood or wood­ based products, making up a total thickness of - normally - 1 5 mm. The surface treatment is carried out in the factory, further working on site is not possible. This type of flooring is laid floating on a layer of impact sound i nsulation, but can also be g lued or secret-nailed to a sub­ floor.

can be repeated several times during the l ife­ time of the floorin g . A damp-proof membrane to protect against moisture is necessary when wooden floor cov­ erings are laid on floors in contact with the soi l . A n expansion joint is necessary between float­ ing wood finishes and all vertical components.

End-grain wood-block flooring Cross-cut sharp-edged blocks with a robust end-grain surface are laid d i rectly on the sub­ strate (fi g . C 6 . 1 2 g) . Species such as Scots pine, larch, spruce or oak are available in thick­ nesses from 22 to 80 mm. We distin guish between two contract ratings: GE for commer­ cial uses, RE for prestig ious purposes.

Surface finish Sealing materials, waxes or impregnation g ive wooden surfaces the necessary protection against moisture and soi l i n g . Coating materials, e . g . based on acrylic resin dispersion, alkyd resin, two-part systems based on polyurethane resin or made from animal or vegetable oils and waxes, can be considered (see "Surfaces and coatings", p. 1 95). Wooden floors remain attractive for a long time; minor imprints and scratches are generally regarded as agreeable signs of wear.

Production and processing Wooden floor coverings are manufactured on an industrial scale. Depending on the type of flooring , the dried and roughly sized pieces of timber are glued to other layers and/or pre­ pared for laying. With the exception of real wood parquet laminate flooring , the surface treatment is carried out after laying. Floor cov­ erings of solid timber are sanded to produce a flat surface after laying and are then treated to protect them . The sanding and sealing process

Properties Although timber basically belongs to build ing materials class B2, some wooden floor cover­ ings, e . g . oak parquet flooring, achieve class B1 (see fig . C 6.20) . Once installed, the hygroscopic behaviour of timber helps to regulate the interior climate. The moisture content of the timber adjusts along with changes in the relative humid ity of the interior air. The moisture absorbed by the timber leads to changes in size, which in the

d

case of severe fluctuations in the interior cli­ mate can result in visible, open joints in the floor covering. Applications The most common species of wood for flooring are oak, beech, maple, alder, ash, cherry, larch and spruce. The less well-known varieties i nclude bamboo, coconut palm and olive, all of which have good Brinell hardness values and are therefore ideal as floor coverings, providing an interestin g surface finish (fig . C 6. 1 2 h). Bamboo I n botanical terms the bamboo plant is a grass, not a tree. The plant's fast g rowth produces a great quantity of biomass. Bamboo's outstand­ ing material properties, e . g . Iow weight, high strength i n compression, tension and bending, plus its relatively easy workability, make it a very useful building material. Bamboo parquet flooring is very long-lasting and harder than oak or maple.

Laminated floors

Laminated floors form a separate group of floor coverings. In most cases the surface finish imi­ tates a wooden floor covering (fi g . C 6. 1 3) . The wearing course consists of HPL (high-pressure laminate) . A layer of transparent melamine

h

C 6. 1 2

1 79

Floors

resin protects the decorative finish printed on paper. The core of the board is made up of several layers of paper and synthetic resin pressed together. The backing is usually a wood-based board, usually wood fibreboard, particleboard or MDF. A backin g paper on the underside prevents the board distorting. Prod­ ucts made exclusively from HPL are moisture­ resistant (solid laminate ) . Owing to their thick­ ness of just 7 mm, laminated floors are fre­ quently used for refurbishment work. Laminated floors are very hardweari n g , but are not antistatic and - apart from solid laminate are susceptible to moisture. Plastic sheeting can be used to protect moisture stemming from vapour d iffusion and moisture trapped in miner­ al building materials. Such floors can be laid floating or firmly bond­ ed to the substrate. Some products have spe­ cially shaped edges which enable the ind ividu­ al pieces to be c l i pped together without the need for any adhesive. As small d ifferences in level at the joints between the elements can become visible when viewed agai nst the light, laminated floors are laid parallel with the d i rec­ tion of the incoming l i g ht. Laminated floors can­ not be refurbished or repaired.

the smoke development (2 development) .

=

moderate smoke

Cork

Feel underfoot and comfort are among the great advantages of cork floors (fi g . C 6. 1 4 b) . For details of impact and airborne sound insu­ lation, please refer to " I nsulating and sealing", p . 1 34. Cork floor coverings are available in two ver­ sions - as cork parquet flooring and as real cork parquet laminate flooring. Cork parquet flooring is glued to the substrate over its full area. Data sheets 3-7 published by the TKB (Technical Commission on Building Adhesives) are helpful . However, real cork parquet lami­ nate flooring is laid floating. Cork floor cover­ ings are usually 4 mm thick, but in exceptional cases can be up to 8 mm thick. Without a suita­ ble surface treatment (sealing or waxing) cork is very quickly soiled. By contrast, PVC-coated cork floor coverings req u i re only minimal care and no further surface treatment, and even meet the req u i rements for chair castors. Clean­ ing and care are reduced to vacuuming and/or wiping with a wet cloth . Cork floor coverings can be recycled as insulating materials. Rubber and synthetic rubber

Resilient floor coverings

Resilient floor coverings are those floor cover­ ings made from synthetic or natural materials that provide a dense, smooth finished surface. Many types are offered in 2 m wide rolls, others in the form of square tiles. D ispersion, solvent, contact and reaction resin adhesives are suita­ ble for the full-bond laying, which is essential. Resilient floor coverings are classified by EN 685 according to their wearing q ualities. The main groups 2 1 -23 are suitable for resi­ dential applications, 31 -34 for commercial and public buildings, and 4 1 - 43 for industrial build­ ings. There is a coding system for identifying the fire behaviour of these products ( D I N EN 1 3 501 - 1 ) : in "5.2", for example, the first d i g it represents the building materials class (5 not read ily flammable) , and the second d i g it designates =

C 6. 1 3

1 80

a

Natural rubber obtained from tropical rubber trees is hard ly offered i n its pure form any more. Synthetic rubber is obtained from crude oil in about 20 d ifferent varieties. Various types of rubber - also natural rubber - are mixed together for floor coverings. Vulcanisation cre­ ates a permanently resilient polymer from the raw materials. These floor coverings are available in 2 m wide rolls or 500 x 500 mm tiles. RAL RG 806 stipu­ lates the quality guidelines for this type of floor covering. Rubber floor coverings are hardwearin g , per­ manently resilient, d i rt-repellent, non-slip, anti­ static and resistant to oils, fats, chemicals and Cigarette burns. They also contain no hazard­ ous chemicals. Rubber is easy to work and thanks to its hardwearing qualities and good impact sound insulation properties (improve­ ment from 8 to 20 dB) is a good choice for pub-

b

c

l i c b u i l d i ngs (fi g . C 6 . 1 4c) . Some products are resistant to ultraviolet light and can also be used outdoors. Honeycomb rubber mats or products made from rubber strips fitted into aluminium sections are su itable for entrance zones. Rubber floor coverings belong to building materials class B 1 , and the normal thickness is 2-5 mm. Linoleum

Linoleum, from the Latin linum ( flax) and oleum ( oil), is a man-made product made from renewable raw materials (fig. C 6. 1 4 a) . The invention of li noleum in 1 863 b y the Eng­ lishman Frederick Walton marked the begin­ ning of manufactured floor coverings. For a long time l i noleum dominated the market for resil ient floor coverings, before - starting in the mid-20th century - PVC gradually took over as the market leader. =

=

Production Linoleum is produced by oxidising linseed oil and mixing it with a natural hardener - colopho­ nium (or common rosin); the mixing ratio is about 4 : 1 . This binder is mixed with roughly equal parts of sawdust and stone dust (chalk) plus cork powder, which is responsible for the elasticity and insulating properties. Pigments are added to g ive the desired colour. The raw material is then calendered (pressed between rollers) in several passes onto a textile (jute or g lass fibre) backin g , dried for several weeks at high temperatures in a kiln and subsequently cut i nto rolls or tiles. Surface finish The natural colour of linoleum is a mottled beige-brown. Pigments are added to provide a whole range of colours from pastel to bol d , with various textures. The surface finish is matt. Yellowing is a phenomenon that appears tem­ porarily as a result of the curing process and is particularly noticeable on l i ght-coloured surfac­ es. However, after a few hours in the daylight this discoloration d isappears.

d

e

C 6. 1 4

Floors

Laying Linoleum must be allowed to reach room tem­ perature prior to processing because it shrinks in the length and expands in the width. It must be laid on a dry, flat substrate, e . g . particle­ board, plywood , screed, concrete. Owing to the possibility of rotting on the underside, water must be prevented from seeping through the joints. Concrete floors in contact with the soil require a damp-proof membrane. Any significant une­ venness in the screed should be made good to ensure that the linoleum does not crack. U ne­ venness in the substrate is particularly noticea­ ble on plain coverings when viewed against the light, which is why the whole surface shou ld be filled prior to laying the linoleum. However, thicker types of l i noleum can compensate for small discrepancies in the substrate. If a jute textile backing absorbs water and expands before the adhesive dries, the linoleum may bulge at the joints. Surface treatment Patterned and plain linoleum floor coverings are normally coated by the manufacturer with a protective matt film, usually an acrylic disper­ sion. As this protective film partly seals the sur­ face, l i noleum is easy to clean. Linoleum manu­ facturers therefore recommend no special measures or cleaning agents for their products. Applications Linoleum can be laid in virtually all i nternal areas and owing to its antibacterial properties is particularly suitable for heavily trafficked sur­ faces in, for example, hospitals, schools and sports facilities. However, linoleum is not rec­ ommended for wet interior areas. Linoleum is easy to keep free from d ust and is therefore from the medical viewpoint - recommended for asthma sufferers (fig . C 6. 1 4 a) . Cork linoleum This floor covering exhi bits similar properties to standard linoleum. The addition of coarse cork powder to the l i noleum mass improves the elasticity and the impact sound insulation, and it also feels warmer underfoot. PVC

PVC floor coverings consist of a homogeneous layer of polyvinyl chloride to which diverse sub­ stances are added (including plasticisers and fillers such as chalk) to achieve specific prop­ erties (fig. C 6. 1 4 d) . The resulting floor cover­ ing is resistant to chemicals and ageing , is non-slip, hardwearing and i nexpensive. PVC flooring is easy to work and if the joints are welded together can even be used to create a watertight surface finish. The electrostatic behaviour ranges from insulatin g to antistatic to electrically conductive depending on the prop­ erties of product and adhesive. This easy-care floor covering is also suitable for more stringent hygiene conditions, e . g . hospi­ tals. Owing to their thermoplastic nature, PVC

floor coverings can be damaged by cigarette burns. And in a fire, PVC gives off hydrochloric acid, which corrodes concrete and steel and releases toxic fumes (CO, d ioxins, PAH) . PVC products belong to building materials class 8 1 (not read ily flammable) . After shredding and preparatory treatment, old PVC floor coverings can be reused in new flooring materials (max. 70% ) , but in practice the amount of material recycled is currently very low. PVC floor cover­ ings are just 1 .0-2 .5 mm thick. Although PVC floor coverings have undergone d i stinct improvements, they are still not without their critics. One non-hazardous p lasticiser that can be used is epoxidised soya oil. The materi­ al's life cycle assessment benefits from the low cleaning requirements and the good durabil ity. Design options PVC floor coverings can be manufactured to imitate certain other materials such as natural stone, ceramics, metals, etc. Countless pat­ terns, colours and textures are available. The design options would seem to be limitless, with new finishes being added all the time. Surfaces with three-dimensional effects are among the latest developments in the PVC flooring market. CV flooring This is a foamed floor covering with a softer layer of PVC beneath the wearing layer (CV = cushioned vinyl) . Such floor coverings exhibit better impact sound i nsulation values. C 6.16 Polyolefins

The search for a substitute for PVC floor cover­ ings resulted in the appearance of polyethyl­ ene, polybutene and polypropylene flooring products in the early 1 990s. These floor cover­ ings can be laid with water-sol u ble adhesives and require no plasticisers. They have simi lar properties to PVC products and can therefore be regarded as viable alternatives (fig . C 6 . 1 4 e). Although their life cycle assess­ ments are better, their market shares are cur­ rently sti l l smal l . Seams in resilient floor coverings

For reasons of hygiene and to enhance the appearance, also to cope with chair castors, joints in resilient floor coverings are often weld­ ed (PVC with a PVC cord, special jointing mate­ rials for linoleum and polyolefins) .

C 6. 1 3 Laminated flooring C 6. 1 4 Resilient floor coverings a linoleum b cork c rubber d PVC e polyolefin C 6 . 1 5 Interactive illuminated floor C 6 . 1 6 Thermosensitive polyester floor covering C 6. 1 7 Linoleum as wall and floor finish, boutique, New York, USA, 2000, Choi-Campagna Design

Outlook

Floor coverings are constantly undergoing developments to optimise their comfort, clean­ ing characteristics and wearing q ualities even further. Two examples serve to illustrate the progress in this field : SAF (=shock-absorbing foam) SAF is the designation for a highly elastic poly­ ester foam. Originally developed for medical purposes, fig. C 6. 1 6 shows the material in use as a floor coverin g . In this case a 25 mm layer of SAF is attached to an underlay of 1 00 mm C 6. 1 7

1 81

Floors

thick polyurethane foam. The depth of the imprint upon loading is influenced by the inten­ sity of the contact and the temperature. A per­ son leaves a trail of footprints until the material has fully recovered . Interactive illuminated floors An interactive illuminated floor is a type of sandwich panel. The uppermost layer is made from an elastic synthetic material, an opaque fluid forms the core, and the backin g layer is glass. A light source underneath can be seen when walking across the floor because the fluid is displaced, which allows the l ight to shine through. The footprints remain visible until the floor covering returns to its original state (fig. C 6. 1 5) .

Textile floor coverings

Rugs and carpets were orig inally hand-made luxury objects designed exclusively for deco­ rating prestigious interiors - on the walls as wel l . Mass production of carpets began in the 1 8th century, a development that triggered a new fashion in England: rooms were no longer decorated with wal lpaper, but instead with heavily patterned carpets. The 1 9th century saw the start of the industrial production of wall-to-wall carpeting, which in the second half of the 20th century underwent considerable developments thanks to the introduction of syn­ thetic fibres. Today, the range of industrially manufactured textile floor coverings encompasses natural fibres, synthetic fibres and blends of d ifferent fibres. A textile floor covering is a product with a wearing layer of textile fibre materials suitable for covering a floor. The wearing layer is called the p i le. The qual ity of a textile floor covering is essentially defined by the material, q uantity and processing of the pile threads. Good impact sound insulation and sound atten­ uation properties plus comfort and a feeling of warmth underfoot characterise textile floor cov­ erings. On the other hand , they are easily soiled and stains caused by fluids (e. g . wine, oil) require time-consuming cleani n g . A huge range of textile floor coverings is on offer in d if­ ferent qual ities and price categories to suit d if­ ferent wearing conditions. Colour, pattern and texture amplify this d iversity to form an almost infinite variety. Properties Textile floor coverings are tested by the manu­ facturers to D I N EN 1 307. This standard speci­ fies weight, beating-up, thickness of wearing layer, fibre material , behaviour in use and phys­ ical parameters, and provides details regarding suitability for potential applications. D I N EN 1 307 d istinguishes textile floor cover­ i ngs accord ing to four contract ratings: 1 low, 2 norma l , 3 heavy, 4 extreme. Owing to their vulnerability to soiling and the ensuing, limited service life, textile floor cover=

=

1 82

=

=

VllVV VllV a

c

b

d

ings are not recommended for heavily traf­ ficked entrance zones. The useful l ife of a tex­ tile floor covering depends heavily on the so­ called surface pile density. This is a theoretical value: weight of pile divided by thickness of pile. The higher this value, the higher is the density in the wearing layer of the floor cover­ ing. Comfort is covered i n D I N EN 1 307 by allocat­ ing textile floor coverings to so-called comfort classes LC 1 -5. Walking across a textile floor covering can lead to electrostatic charges building up. The electrostatic properties can be improved with a chemical coatin g , or - a more durable solution - by weaving in stainless steel or copper threads, or yarns with a carbon con­ tent. Textile floor coverings belong , in principle, to building materials class B 2 (flammable). How­ ever, testing can result in a further d ifferentia­ tion i nto classes T-a, T-b and T-c. Class T-a is the best and corresponds to building materials class B1 (not readily flammable) , whereas T-c is approximately class B3 (highly flammable) . Further suitabil ity recommendations ease the choice of the optimum product. For instance, details regard ing light-fastness, suitability for wet interior areas, chair castors and staircases are all common.

fibres of which point upwards. In a velour the threads of the yarn are cut, and the surface consists of these cut ends (figs C 6. 1 8 c and C 6. 1 9 c) ( cut-pile carpet). I n looped-pile carpets (boucle) the ends are not cut (figs C 6. 1 8 d and C 6. 1 9 b) . Needle-punch floor coverings have a wearing layer of a consolidated fleece consisting of fibres (fig . C 6. 1 8 b). Natural fibres such as jute cloth or synthetic fleeces can be used as the backing material for the pile.

Structure Textile floor coverings are deSignated accord­ ing to their basic material but also accord ing to their structure and backing. We d istinguish between flatweave and pile carpets (fleece, velour and boucle) . Flatweave carpets Flatweave carpets are produced on weaving looms (figs C 6. 1 8 a and C 6 . 1 9 a). Warp and weft threads form a relatively thin wearing layer; a further layer (backing) can enhance the com­ fort. The most common materials used are natural plant fi bres such as coconut, sisal and jute. Pile carpets The wearing layer i n a pile carpet is formed by the pile. Woven into a backing material, the pile forms a dense, resilient layer of thread, the

C 6. 1 8

=

Backing material Foamed coatings, synthetic fleeces, poly­ urethane or latex coatings and jute cloth can be considered as backing materials. In velour products the backing material also provides the fixing for the threads of the pile. Fleece backings improve the comfort underfoot, but soft foams are not suitable for chair castors. Products with a so-called secondary, textile backing are often recommended for office bui ldings. These floor coverings can also be completely removed from the substrate even if they were originally g lued down, whereas foam backings often leave a residue behind which must be removed - a time-consuming opera­ tion. Production Woven carpets req u i re three groups of threads parallel with and two transverse to the d i rection of production. The stitching warp pulls the lon­ gitudinal pile threads onto the two transverse wefts above and below the longitudinal filling warp. The weaving is assisted mechanically by the so-called round wires. If these are blunt, the loop of the pile is retained, and boucle (Iooped­ pile) goods are the result. Blades on the round wires produce velour (cut-pile) goods. The tufting method sews the loops to a backing material to create loops on the underside. Only a coating on the underside g uarantees a per­ manent attachment. Looped-pile carpets con­ sist of one continuous thread. If the loops are cut, the result is a cut-pile carpet, similar to velour. One great advantage of this method is the speed of production, which is up to 20 times faster and hence less costly.

Floors

The needle-punch method joins and compacts loose fleece plies with the help of needles to form a very hardwearing floor covering. Nee­ dles fitted to beams punch through the pre­ pared fleece at high speed , barbs cross the fleece layers with one another and with the backing material. An impregnation treatment seals the fibre composite. Kugelgarn® consists of countless fibre spheres that form a three-dimensional and very robust wearing layer (fig. C 6 . 1 9 f) . Other methods such a s knittin g , flock coating , pressing, bonding, etc. are not covered here. Laying Most carpets are g lued to the substrate over their full area. The residual moisture content of concretes or screeds must be tested before­ hand. Floor coverings with a foam backing can­ not be detached from the substrate without ruining the covering completely. New types of adhesive are being developed that wi l l adhere to the carpeting and ease replacement.

Laying loose Smaller areas can also be laid loose or secured with double-sided adhesive tape. However, general usage as wel l as temperature and moisture fluctuations can easily lead to bulges. Carpet tiles are suitable for contract carpetin g , especially in conjunction with raised floors. Their heavyweight backing material enables them to be laid loose and so the accessibil ity of the raised floor is thus retained . Laying with gripper strips It is possible to attach carpets to strips of steel hooks. These so-called gripper strips are fixed to a stable substrate adjacent to the walls and the carpet is stretched tightly between them. Carpets for this type of laying should have a stable secondary, textile backin g . An approx. 6 mm thick fleece can be used as an underlay. This type of floor covering is not suitable for . use in conjunction with underfloor heating because the fleece underlay functions as ther­ mal insulation. Laying with gripper strips makes replacement at a later date much easier, and the comfort and lifetime of the carpet are con­ siderably improved (up to 50% longer life) . This is an environmentally friendly technique because both fixings and fleece underlay can be reused. Cleaning and care Carpets can be cleaned with brushes and vac­ uum cleaners. The more intensive special cleaning measures include foam treatments and cleaning by special companies. Whether soiling is readily or less readily noticeable depends on colour, colour intensity and pat­ tern. Fibre materials and structure also have an influence on the frequency of clean i n g . People with house dust allergies are generally advised to avoid textile floor coverings.

Natural fibres

Natural fibre carpets are divided into those based on vegetable materials and those based on animal materials. It is generally true for all natural fibre floor coverings that as the comfort increases, so the wearing q ualities decrease. In addition, the carpets offering better comfort are less hardwearing than comparable carpets made from synthetic fibres. This is probably the cause of their low market share. Natural fibre products are frequently g iven a chemical surface coating to help conserve the fibres, to optimise the soiling behaviour and to protect against moths and other vermi n . The coating adheres to the fibres but wears off d uring use.

C 6. 1 8 Types of carpet a flatweave b fleece c velour d looped pile C 6. 1 9 Textile floor coverings a flatweave b looped-pile carpet (boucle) c velour d wool carpet e sisal f Kugelgarn®

Vegetable fibres Carpets made from vegetable fibres such as hemp, sisal, coconut and jute are mainly avail­ able in the form of flatweave goods (fig. C 6.1 ge). On the other hand, cotton fibres can also be used as a pile material, which in contrast to other floor coverings is not elastic, but has a p leasant feel. These carpets are hardwearing and available without moth protection. Animal fibres Carpets made from animal products such as hair and silk are mentioned here for the sake of completeness. Animal hair such as wool, camel hair, etc. have a very good sorption capacity. Additions to the wool , e . g . goat hair, improve the wearing qualities of the floor covering. Wool Wool carpets are available i n two qualities: new wool is obtained by from sheep by sheari n g , b u t recycled or reprocessed wool c a n also b e used. New wool products exhi b it high elasticity, are not susceptible to soiling and are not readi­ ly flammable. The high moisture absorption capacity of wool has a beneficial effect on the interior climate. Blending with synthetic fibres improves the wearing q ualities of wool carpets (fig . C 6. 1 9 d) . The "Wool mark" is an interna­ tional symbol of q uality which g uarantees that the wearing layer is made from 1 00% new wool . Synthetic fibres

Synthetic fibres are man-made goods pro­ d uced from crude oil products. As a rule, they cannot absorb any moisture. The advantage of this is that they are resistant to staining by drinks and simi lar fluids. I n itially smooth fibres can be mechanically prepared to improve the feel and the resistance to soil i n g . Coatings can improve the electrostatic properties and the soiling behaviour, or are i ntended to protect the material against fad i n g .

d

Polyamide fibres (PA) The most common fibres exhibit a high wearing resistance, minimal soi l i ng vulnerabil ity and a good regeneration capacity. They can be u pgraded to antistatic floor coverings by add­ ing carbon to the fibres. Owing to their good C 6. 1 9

1 83

Floors

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Floor covering

Normal Normal thickmethod ness of fixing

Density

[mm]

[kg/m"]

Weight

Thermal conductivity

Water vapour diffusion resistance

[kg/m>]

[W/mK]

H

Building materials class/ combustibility class

Contract ratings available

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Stone granite marble travetine slate reconstituted stone

1 0- 30 1 0-30 1 0- 30 1 0-15 1 2 -50

mortar, thin-bed mortar 2600-2800 2600-2900 2400-2500 2700-2800 2200-2400

26-84 26-87 24-75 27-36 26-120

2.8 3.5 2.3 2.2 1 .6 - 2 . 1

1 0 000 1 0000 200/250 800/1 000 70/150

A 1 /A" A 1 /A" A 1 /A" A1/A" A 1 /A"

D I N EN 1 4 1 57 pt 1 -4 (for nalural stone tiles < 1 2 mm thick)

Ceramics stoneware tiles earthenware tiles split-face blocks engineering bricks

7-1 5 5-9 8-1 1 1 0-40

mortar, thin-bed mortar 2000-2400 2000 2000-2400 vibratory compaction, 2000-2200 elutriation

1 4-36 1 0- 1 8 1 6-26 20-88

1 .0 1 .0 1 .0-1 .05 0.96 - 1 .2

1 00/500 ' 1 00/500 ' 1 00/500 ' 1 50'

A1/A" A1IA" A1/A" A 1 /A"

D I N 1 4 4 1 1 pt 1 -5 glazed tiles

nailed, floati ng nailed, glued glued glued glued, floating glued, floating

430-760 430-760 430-760 430-760 740 800

6-30 6-1 7.5 3.5-7.5 4-1 7 5-19 6-9

0.09-0. 2 1 0.09-0. 2 1 0.09-0. 2 1 0.09-0.21 0. 1 5 0. 1 7

40 40 40 40 50/400 1 000/2500 4

up to 8 1 / 8,, -s1 l0 E" up to 8 1 / 8,,- s 1 l0 E" up to 8 1 / 8,, -s 1 to E" up to 8 1 / 8,,-s1 l0 E" up to 81/8,,-s1l0 E" u p to 8 1 / 8,, -s1 l0 E"

not std . ; differs considerably dependin9 on species of wood ·

2-6 2-5 2-5 2-3 2-3

glued, floating full/partial gluing full/partial gluing full/partial gluing full/partial gluing

400- 500 1 200 1 000-1 200 1 700 1 500-1 700

1 -3 2-6 2-6 3-5 3-5

0.065-0.07 20/40 0.1 7-0.64 1 0 000 0.08-0. 1 7 800/1 000 0 . 1 0-0.25 1 0 000 0.23-0.25 1 0 000

5-8 5-6

full/partial gluing between gripper strips

200 200

1 -2

0.06 0.54

0

Wood solid floorboards 1 5 -40 wood-block flooring 1 4 -22 mosaic parquet 8-10 block-on-edge parquet 1 0 -25 wood parquet laminate 7 - 26 laminated flooring 7-1 1

0 0 0 0

0 0

D I N EN 1 4354; 2 1 -23, 31 -33 DIN E N 1 3329; 2 1 -23, 31 -33

.3

.3

0

Resilient floor coverings cork rubber linoleum PVC polyolefins

up to 8 1 / 8,, -s1 l0 E" D I N EN 685; 21 -23, 3 1 -34, 8 1 / 8,, -s1 to C,,-s1 4 1 - 43 up to 81/C,,-s1 to E" up to 8 1 / 8,,-s1 to E" up to 81/8,,-s1 to E"

0

0 0

.3

0

0

.3

0

02

.3

0

02

.3 .3

Textile floor coverings carpeting needle-punch fleece

5 5

up to 81/8,,-s1 to E" DIN EN 1 307 1 , up to 81/8,, -s1 to E" 2, 2+, 3, 4

0 0

0

' These values apply to ceramics in situ; individual values, e.g. stoneware tiles 1 2 000; earthenware tiles 1 0 000. With backing 3 When used in conjunction with underfloor heating, a full bond with the substrate is essential. 4 Values apply to a single panel of laminated flooring without joints. 2

wearing q ualities, polyamide fibres are used for the so-cal led walk-off mats and carpets manu­ factured for entrance zones.

before spinning to form a yarn. Dying can take place at any stage of the carpet manufacture. Blends

Polyacrylonitrile fibres (PAN) These fibres have a similar feel to wool , but are more hardwearing. Polyester fibres (PES) Besides their high wearing resistance, polyes­ ter fibres have a gloss surface. They absorb only very l ittle moisture. Polypropylene fibres (PP) Polypropylene fibres repel moisture and are not affected by ultraviolet radiation, and therefore can be used externally and in wet interior areas. The regeneration capacity is low, which means that these fibres are preferably used in the form of fleeces.

C 6.20 C 6.20 Parameters of floor coverings C 6.21 "Shining Islands", polyamide carpeting with fluorescent coating, furniture trade fair, Cologne, Germany, 2002, Nether C 6.22 Life cycle assessment data for floor coverings

Basically, all types of yarn can be used in any combination for the production of a carpet. As the properties vary in proportion to the ratio of the d ifferent fibres, it is easy to reach an opti­ mum performance. Depending on the intended range of applications, it is possible to combine, for example, natural fibres with more hardwear­ ing synthetic fibres, or for synthetic fibres to achieve a more pleasant feel by incorporating natural fibres. Outlook

The use of certain coloured coatings and struc­ tural measures can enable textile floor cover­ ings to generate a three-dimensional impres­ sion. Fig. C 6.21 shows an example of synthetic fibres with fluorescent properties.

Yarn manufacture A melt of the corresponding plastic granulate is forced through a die (spinnerette) at high pres­ sure, and the length of the fibres increased by drawing. The fibres are initially too smooth for processing. They are therefore given a texture C 6.21

1 84

Floors

EP eutrophication [kg PO.eq]

Durability POCP summer smog [kg C2H. eq] [a]

0.0050

0.00041

0.0010

70- 1 00

0.0 1 5

0.00 1 6

0.0020

70- 1 00

0

0

0.043

0.0051

0.052

40-80

0

c::::J

c:::=J

0.053

0.0044

0.0080

40-80

c:::J

c:::J

0.026

0.0030

0. 1 4

20-50

0

0

0.041

0.0035

0.0050

20-50

0

0

0.033

0.0036

0.10

20-50

0

0

�

0.033

0.0033

0.057

0

D

c::J

0.037

0.0028

0.0050

10-15

D

0

0.01 1

0.00 1 4

0.0020

1 5-40

0.078

1 5-40

PEI primary energy non-renewable [MJ]

PEI primary energy renewable [MJ]

AP GWP ODP global acidifiozone cation depletion warming [kg C02 eq] [kg R 1 1 eq] [kg S02 eq]

16

0.7

1 .0

0

slate'

43

1 .1

3.5

0

slate flags, 300 x 300 mm, MG I I I mortar joints, 20 mm MG 11 mortar bed, 1 2 mm

•

Floor coverings Layers • for origin of data see "Life cycle assessments", p. 1 00

Natural stone limestone' limestone flags, 305 x 305 mm, MG I I I mortar joints, 1 0 mm thin-bed mortar, 3 mm

0

Ceramics terracotta

1 37

terrac. tiles, oiled, 300 x 300 mm, MG I I I mortar joints, 1 5 mm MG 11 mortar bed, 1 2 mm

-

glazed ceramic tiles'

1 62

glazed tiles, 1 00 x 200 mm, MG I I I mortar joints, 8 mm thin-bed mortar, 3 mm

-

14

3.2

0

�

5.1

5.3

0

=

Solid timber and wood-based products wood-block flooring

66

wood-block flooring, beech, oiled, 22 mm alkyd resin adhesive

-

mosaic parquet

79

mosaic parquet, oak, sealed, 8 mm alkyd resin adhesive

-

wooden floorboards

84

floorboards, larch, oiled, nailed, 1 9.5 mm battens, 80 x 80 mm granulated cork fill, 50 mm

-

real wood parquet laminate flooring

74

real wood parquet laminate flooring, beech, 15 mm polyurethane adhesive laminated flooring laminated flooring with melamine resin coating, 8 mm polyurethane adhesive polyethylene fleece (PE)

447

1 74 �

487

31 1

-42

-13

0

0

c:::===J -44

-27

0

0

91

-

54 CJ

-2.6

0

0

20-50

Resilient floor coverings linoleum

24

linoleum (roll), 2.5 mm polyvinyl acetate (PVAC) adhesive

•

rubber

702

29

-0.4

0

0

15

0

21

0

0. 1 9

rubber (roll) without inlay, synthetic, 4.5 mm polyurethane adhesive

0.Q1 6 I j

cork, waxed

22

cork tiles, waxed, 6 mm latex adhesive

•

PVC

1 18

PVC (roll), 2 mm polyvinyl acetate (PVAC) adhesive

-

54 CJ

23 0

-5.2

0

0

=

1 5-40

0.0022

0. 1 1

0

c:::::::=:::J

0.066

0.0059

0.0070

1 5 -30

c:=J

c:::=J

0.047

0.0038

0. 1 0

5- 1 5

=

=

�

0.Q1 1

0.00081

0.082

0.0 1 0

= g.g

I c::=::J

Textile floor coverings carpet, natural sisal

1 64

carpet, natural sisal, natural latex backing, 6 mm alkyd resin adhesive

-

carpet, new wool

39

carpet, new wool , looped-pile, 6 mm jute felt polyvinyl acetate (PVAC) adhesive

•

carpet, fully synthetic

225

carpet, cut-pile, foam backing, 7 mm polyvinyl acetate (PVAC) adhesive

33 0

27

3.3

0

0

-1 . 1

0

c::=:J

0

5.2

5- 1 2

7.3

=

0

0.079

0.0077

0.027

c::=:J

C=:J

0

5- 1 2

C 6.22

1 85

Surfaces and coatings

As the boundary between materials and the environment, surfaces stimulate the senses, I ni­ tially, it is the visual impression of a surface that dominates, This depends on the nature of the surface, which may be, for example, smooth, shiny, rough, wavy or decorated, An object or a b u i l d i n g can appear in any gradation from heavyweight to transparent d ue to the incident light, colours and reflections, Additional haptic, acoustic, sometimes even olfactory, sensual perceptions triggered by a material have an influence on the quality of an object beyond its mere constructional and functional uses,

I n ancient Egypt and later in Greece, the sym­ bolic use of colour played a role in sculptures and architecture, In ancient Rome plaster or stucco reliefs imitated marble and clay clad­ d i n g , And the i nteraction between architecture, painting , sculpture and ornamentation was deliberately sought d uring the Baroque era, Classicism, the antithesis of late Baroque and Rococo, looked back to the ancients, During these periods the "white architecture of the ancient times" was the ideolog ical motivation, White was a metaphor for honesty and purity in architecture,

The surfaces of the building envelope are exposed to severe stresses and strains, C l i mat­ ic and environmental influences alter the sur­ faces over the course of time just as much as the traces of everyday use, Some materials possess an ageing q uality and acqu i re a pati­ na, but others require regular renewal or care to prevent decay, If the materials used to not resist ageing or do not form a patina, their durabi l ity and hence the retention of their mate­ rial value depends on the maintenance cycles of the coatings intended to protect them, Coat­ ings are invisible means of prolonging the l ife­ time or modifying the properties of materials, They refine the substrate by highlighting the typical features of the material or by provid i n g a f u l l protective coveri n g ,

During the 1 920s and 1 930s pure white coat­ ings were regarded as the ideal surface finish, the aim of which was to prevent diverting atten­ tion from the architectural and constructional concepts, During the same period , Bruno Taut used colour as an inexpensive architectural medium. By al locating this medium a symbolic and emotional meaning, he brought about a new social identification with the building, And Le Corbusier, talking of colour, said : "Colour as a means in architecture is just as powerful as the p lan layout and the profile. Or put a better way: polychromy is a constituent of the plan layout and the profile itself."

Liq uid or paste-like coating materials, plasters and renders are applied in one or more coats and form a protective system compatible with the substrate, Pigments and fillers made from stone dust can be mixed in to add colour to the surface, Although coatings account for only a small fraction of the cost of erectin g a structure, the appearance of the surface has a crucial effect on the architecture,

Colour

The word colour has several meanings and is used by the layman and expert alike to describe different aspects, which can lead to many misunderstandings. D I N 5033 defines colour as a sensation; it is therefore not a phys­ ical property of an object. Referring to paints and other coating materials simply as "colours" should therefore be avoided. Perception of colour

C 7,1 C 7,2 C 7,3 C 7,4

White l i g ht is the electromagnetic radiation with wavelengths between 380 and 780 nm. It was in 1 705 that Isaac Newton first split white light systematically into its constituent wavelengths the spectrum - with the help of a g lass prism, The spectrum consists of the monochromatic spectral colours violet, indigo, blue, green, yel­ low, orange and red . Both ends of the spec­ trum exhibit visual similarities, and joining the ends together forms a colour wheel. All the other colours are formed by mixing together the colours of the spectrum, e . g . magenta is formed by blending red , orange, violet and blue. Only when the beams of light enter the human eye and trigger a colour stimulus in the brain can the observer describe a colour and place it in relation to other colours. Our perception of colour is determined by its two fundamental forms: self-luminous colours generate the colour stimulus when the coloured light from a source of radiation enters the eye d i rectly or through a filter, whereas object col­ ours generate the colour stimulus when a part of the light is reflected from the surface of an object before striking the retina. An object that

Satellite City Towers, Mexico City, Mexico, 1 957, Luis Barragan NCS colour solid with colour triangle NCS colour wheel Monastery of La Tourette, Eveux-sur-Arbresle, France, 1 960, Le Corbusier C 7.1

1 86

Surfaces and coatings

� y

absorbs all the light incident upon it appears black. Object colours are always perceived in relation to other colours and also depend on the colour of the incident l i g ht.

15

;:

is

� I ...

$'

. "" ""��

..,of'
Mixing colours

The mixing of two or more colours results in a further colour. We d istinguish between two fun­ damental types of mixin g . Additive mixing is the combination of coloured light. The primary additive colours are blue, green and red . Sub­ tractive mixing is carried out using object col­ ours in the form of pigments or dyes. The pri­ mary subtractive colours yellow, magenta and cyan can be mixed to form any other colour. Both forms of mixing create a relationship: two primary add itive colours mixed together result in a primary subtractive colour and vice versa; for example, red plus green produces yellow, and mixing the primary subtractive colours yel­ low and cyan results in the primary additive colour green. Colour reference systems

The human brain can d istinguish about 1 0 mil­ lion d ifferent colours. I n order to describe them uniquely and understandably, we generally call upon the three parameters for characterising colour perception : hue, brightness and satura­ tion . The hue is determined by the position within the spectrum or a defined colour wheel. The brightness of a colour designates its lightness or darkness. The saturation denotes the strength of the hue with respect to its brightness. These three parameters form the basis of numerous colour systems, presented in three dimensions in the form of colour solid models, e . g . the NCS colour solid (fig. C 7 . 2 ) . The models use a selec­ tion of colour samples and numerical codes that approximate consistent gradations within the colour solid. For the architect, the inde­ pendent colour systems form the most impor­ tant means of communicating colours to the cli­ ent, contractor and manufacturer. Some of the popular colour systems with their d ifferent ways of describing hues are outlined below.

'Igo"

R

G

Aloe 11208

11308

'" �1

�#

"

qj' C 7.2

Contrasting with this is the RAL colour system which contains 1 688 colours determined by metrological means. These have positions in a colour solid arranged in a colour wheel accord­ ing to the angle of the hue, plus the brightness and saturation in per cent. The three parameters result in a seven-digit code, e . g . RAL 1 90 70 40. Natural Colour System (NCS) I n the NCS, the positions of the 1 950 colours are not based on a specified mixing ratio, but instead on a visual evaluation. This system can therefore be used in any industry. The primary colours yel low (Y) , red ( R ) , b l ue (B) and green (G) are d istributed over the q uadrants of the 40-part NCS colour wheel (horizontal section through middle of colour solid) (fig . C 7.3). The vertical section through the colour solid forms a

I

g /if a;is

B �Cl

� �

'I' a 1> & '2 ""8 ""8

C 7.3

triangle with white (W) , black (S) and one hue of the colour wheel. The various nuances lie between (fi g . C 7.2). The desig nation of a hue is based on its rela­ tionship to the six primary colours. For example, 20-50 R 1 0B means 20% black content, 50% colour content from a coloured hue of the colour wheel, in this case red with 1 0% blue content. Colour spaces (CMYK, RGB) For design purposes, graphic applications and the production of printed products, the Pantone colours, for example, can supplement the pri­ mary colours cyan, magenta, yellow and black of the CMYK colour space. Monitors and televi­ sion screens are illuminated by the light colours of the RGB colour space - additive mixtures of red , green and blue.

DIN colour system The object colours in the 24-part colour wheel are defined at equal intervals accord ing to how we perceive them . The numberin g begins with yellow ( 1 ) and continues past red (7) , blue ( 1 6) and green (22), and finally returns to yel low. The hemispherical colour solid uses this as its base. In addition to the D I N hue (T) , there is the DIN saturation level (S) - 0 (non-coloured) to 6 (coloured) - and the darkness level (D) - 0 (white) to 1 0 (black) . So, for example, 2 1 :4:3 is the DIN T: S: D colour code for a shade of light green. RAL colour chart, RAL colour system The traditional RAL colour chart is a col lection of unrelated colours which have been g i ven an arbitrary four-digit code and a descriptive name, e . g . RAL 3000 "flame red" .

1 87

Surfaces and coatings

Binders for plasterwork

Plasterwork for special purposes lightweight plaster

Organic binders

Inorganic binders

slurry plaster

insulating plaster

magnetic plaster

renovation plaster

X-ray-resistant plaster

pure acrylate polymers

gypsum

acoustic plaster

thermal insulation compo­

styrene acrylate polymers

anhydrite

fire protection plaster

site system

vinyl acetate copolymers

non-hydraulic lime

plaster for heat storage

sil icone resin

hydrau lic lime

sacrificial plaster

cement

damp-resistant plaster

loam/clay sil icates

C 7.5 Plasterwork

Plasters and renders take on functional and architectural tasks on the internal and external surfaces of buildings. The materials used must withstand mechanical and climatic loads, pro­ tect the underlying materials against water or frost, and prevent an accumulation of moisture in and on the building component. As the severity of the moisture effects i ncrea­ ses, then generally so do the requirements placed on the plasterwork as wel l . The strength, shrinkage and cracking behaviour, absorptive properties and thermal conductivity of the sub­ strate affect the choice of a suitable p laster or render system . Materials

Plasters and renders applied to wal l s and sof­ fits in one or more coats do not achieve their desired properties until they have hardened on the building component. These properties depend on the materials used, in particular the binder, p lus the mixing ratio and the nature of the hardening process: Mineral binders, mineral plasters/renders and their mixing ratios are specified in D I N V 1 8 550. The mineral binders include lime, cement, gypsum and anhydrite. Loam, silicate and other non-standardised binders are also used (fig . C 7.5). Organic binders in the form of dispersions or solutions of polymer resins can be mixed with fillers to produce coatings that look remarka­ bly like plaster; these are also known as resin plasters. Mineral and organic aggregates have differ­ ent structures and form characteristic surface textures depending on grain size and meth­ od of plastering or renderi n g . The aggre­ gates should not contain constituents that could have a detrimental effect on compres­ sive strength or waterproofing properties, or lead to spalling, discoloration or efflores­ cence, e . g . erodable and swellable sub­ stances, salts, acids and sulphur com­ pounds. The mixing water controls the viscosity, the workabil ity and the hardening process.

1 88

The addition of fibres may help to reduce cracking. Light-fast lime- and cement-resistant pig­ ments can be used to colour the plaster or render. Dark-coloured plasterwork is subject to more severe thermal stresses than a light­ coloured equivalent, especially in the case of wel l-insulated components exposed to solar radiation. Phase change materials (PCM ) , e . g . in the form of micro-encapsulated paraffins, added to gypsum plaster contribute to passive cool­ ing of the b u i l d i n g . Like with concrete, additives a n d admixtures can be used to influence the flow behaviour, setting time, adhesion and waterproofing properties of the plastering mix or hardened plasterwork. Forms of supply

Plasterin g mixes can be supplied ready-mixed in a suitable consistency for using immediately on the building site. Premixed dry materials in powder form supplied in paper sacks or d i rect­ ly from an on-site silo merely have to be mixed with the specified quantity of water before using . Only rarely are the individual compo­ nents mixed together on site. Classification to DIN 1 8550 and EN 998-1

D I N 1 8 550 links the building performance properties of ready-mixed plasteri ng mixes with the type of binder. The five groups MG P I to MG P V are therefore allocated certain binders and mixing ratios. Applications can be defined on the basis of the d ifferent strengths and water vapour d iffusion properties. EN 998-1 replaces the above groups with a classification according to compressive strength (CS I to CS V) , capi l lary water absorp­ tion (W 0, W 2, W 3) and thermal conductivity (T 1 , T 2). This classification leads to new codes for plastering mixes accord ing to prop­ erties and purpose, but there are overlaps in the compressive strength values and binders are not specified. Therefore, the user cannot deduce the constituents from this classification and design a proper plasterwork system . I n order t o rectify this shortcomi n g , the draft

C 7.6

standard D I N V 1 8550 (based on the old D I N 1 8550) was publ ished in April 2005. The draft takes into account both systems of classi­ fication, compares the old groups with the new EN classification and specifies binders and applications in this context (fig . C 7 . 1 0) . The following i nformation is based on D I N V 1 8550. Applications

We generally distin guish between (gypsum) plaster and (cement) render depending on the position of the material within the structure, and hence the stresses and strains to which it is subjected. Render The average thickness of render, usually applied in two coats, is 20 mm (single coat 1 5 mm) . In normal climatic conditions lime hydrate is suitable as a binder for render (MG P I, MG P 1 1 ) . In the case of unfavourable weather conditions, the render should exhibit water-repellent characteristics (MG P 1 1 , addi­ tives, further coatin g ) . Sol i d cement mortar (MG P I l l ) with very low absorption is used on pl inths and below ground level. Plaster Plasters for walls and soffits are normally appl ied in a single coat 1 5 mm thick using MG P IV and M G P V mixes. They form a flat, absorbent, water vapour-permeable layer which is suitable as a substrate for paint and wallpaper. Plasterwork systems

A plasterwork system is the substrate plus coordinated coats of plaster/render. Basically, the compressive strength of the coats should decrease towards the outside and should not exceed that of the substrate. The substrate therefore accommodates stresses due to tem­ perature-related shrinkage and swelling without leading to cracking or spalling of the plaster/ render. The d iffusion-equivalent air layer thick­ ness Sd of any plasterwork should not exceed 2.0 m .

Surfaces and coatings

Substrates and backgrounds The many diverse building materials such as clay masonry, aerated concrete, timber, fibre­ boards and insulating materials, even existing plaster or render, must exhibit appropriate sur­ face characteristics (roughness, absorbency, load-carrying capacity) so that the plasterwork forms a permanent bond with the underlying material. If - owing to irregularities, inadequate adhesion or strength - the substrate is not suit­ able for direct application of the plaster or render, a background must be applied to the whole area of the load bearing component. This can take the form of wire mesh, expanded metal, bulrush mats, synthetic or g lass-fibre cloths. Stop and angle beads are used at cor­ ners, edges, reveals and transitions to other building materials. These protect the edges of the plaster/render, create a reference point for the thickness of the coats, and encourage the application of a flat surface finish. Undercoats and finish coats The undercoat levels off irregularities in the substrate and, for external applications, guar­ antees the required moisture protection. It accommodates stresses without cracking. For external applications, the finish coat will exhibit water-retardant to water-repellent prop­ erties, the aim of which is to prevent precipita­ tion seeping through to the coat(s) of render underneath. At the same time, it should still be possible for water vapour to escape to the out­ side so that the building components can dry out quickly. The colour and surface texture of the finish coat determines the appearance of the building (see p. 1 91 ) . Plasterwork i s applied manually or with machines, but decoration is always applied by hand. The previous coat must always be hard and dry in order to g uarantee the adhesion of the following coat, and hence prevent shrink­ age cracks.

and are afterwards weather-resistant. Plasters/ renders with hydraulic lime (MG P 1 1) also set under water. Compared to non-hydraulic limes, they have a higher strength and better resist­ ance to moisture. Lime p lasters/renders are suitable for almost all absorbent substrates. They bond airborne pol­ lutants, have a d isinfecting effect and are open to d iffusion. Small q uantities of polymer d isper­ sions and cement ( l ime-cement mix) accelerate the setting process and create a water-retard­ ant product. The addition of gypsum increases the strength of the plasterwork (fi g . C 7.8). Cement render

Cement mortars (MG P I l l ) are used wherever a high resistance to moisture is req uired, e . g . basement walls, plinths. However, moisture underneath stemming from the substrate will cause the cement render to become detached. A strong , rigid cement render is used for exposed aggregate finishes and surfaces sub­ ject to high mechanical loads. Owing to its low sorption capacity, cement render is not ideal for internal applications. The addition of lime (cement-lime mix) improves elasticity, vapour permeability and water absorption capacity. Loam plaster

A mixture of clay minerals, water and fine sand can be used for undercoats and i nternal appli­ cations. As the plaster sets, the water evapo­ rates and reduces the volume. Animal hair or plant fibres used as a filler can help to prevent shrinkage cracks. Loam p laster does not cure - it is solely the water content that determines the degree of hardening. Loam plasters bond wel l and can be sculpted. Their high water absorption capacity results in a pleasant interi­ or c l imate. When used externally, additives or MG P 1 1/1 1 1 finish coats protect the loam plaster against the effects of moisture. Various aggre­ gates and pigments make a variety of surface finishes possible.

C 7.5 C 7.6 C 7.7 C 7.8 C 7.9

C 7.8 Systematic classification of binders for plaster­ work Systematic classification of plasterwork for special purposes Facade relief, apartment block, Vienna, Austria, 2003, ROdiger Lainer Lime render in various styles, Bernhardskapelle, Owen, Germany, 2002, Hans Klumpp Rubble masonry and concrete with white coating, "Yellow House", Flims, Switzerland, 2001 , Valerio Olgiati

Gypsum plaster

Gypsum to EN 1 3 279 can be mixed with water, sand and lime in d ifferent ratios to create gyp­ sum, gypsum-sand, gypsum-lime or lime-gyp­ sum plastering mixes (MG P IV) . I nternal appli­ cations use primarily a single coat of sprayed (or projection) plaster with excellent adhesion. Gypsum plaster regulates the humidity of the internal air, but is not moisture-resistant, and is therefore not suitable for wet interior areas. At very high temperatures (e.g. during a fire) gypsum plaster (building materials class A) loses its chemically bonded water and thereby consumes thermal energy. The ensuing semi­ hydraulic material helps to insulate against the heat of the fire. Lime plasterwork

DIN EN 459-1 classifies building l imes as non­ hydraulic and hydraulic. These represent the most important mineral binders for plasterwork. Plasterwork with non-hydraulic lime (MG P I ) set with water a n d carbon d ioxide from t h e a i r

Plasters based on polymer dispersions

Coating materials with a plaster-like appear­ ance are generally known as resin plasters. These consist of dispersions or solutions of polymer resins as the binder plus organic or inorganic fillers with the majority of particles > 0.25 mm. These plasters are supplied ready­ mixed by the manufacturer. D I N V 1 8550 clas­ sifies them as P Org 1 (for i nternal and external use) and P Org 2 (for internal use ) . The advantages o f plasters with polymer resin binders are their good adhesion (suitable for many substrates) , low risk of crackin g , the thin coats (2-6 mm) , the numerous colours availa­ ble and their resistance to driving rai n . In order to improve the adhesion even further, it is nec­ essary to apply a primer to the substrate beforehand. Plasters with polymer resin bind­ ers are used in thermal i nsulation composite systems and also as a finish coat over existing mineral plasters. Surface textures similar to scratched, scraped or sprayed plaster are C 7.9

1 89

Surfaces and coatings

possible, depend i n g on size of grains and method of plasteri n g .

Plasters for special purposes

The plasters given below are factory-mixed and supplied ready to use (fi g . C 7.6) . Their proper­ ties are not determined by the type of b inder, but rather by the interaction of the constituents selected. Manufacturers' technical data sheets provide information on methods of application, addition of water, working time and working temperature. Lightweight plaster

Lightweight plasters have mineral binders and belong to groups MG P I and MG P 1 1 . They have an oven-dry density of 600-1 300 kg / m3 , contain mineral or organic aggregates and ex­ hibit a porous structure. The l i ghtweight aggre­ gates influence thermal conductivity, compres­ sive strength and modu l us of elasticity. In terms of strength and deformation, l i g htwei g ht plaster is suitable for use on thermally insulating sub­ strates made from aerated concrete, perforated clay bricks or lightweight concrete. Plaster for fire protection

If certain components requ i re better fire protec­ tion, they can be protected with plaster. The duration of fire resistance depends on the type of plaster and its thickness. Gypsum plaster (MG P IV) contain chemically bonded water, which is released as the temperature rises and therefore cools the component temporarily and slows down the spread of the fire. Products belonging to group MG P II can con­ tain incombustible, porous, thermally insulating aggregates, e.g. perlite or vermiculite, which

Plastering mix class to DIN V 1 8 550

PI

a b c a

Type of plasterl render

Min. comp. strength after 28 days; quality grade [N/mm>]

non-hydraulic lime mortar hydraulic lime mortar mortar with hydraulic lime

also delay the heat-induced failure of steel components. The plaster must adhere well to the substrate, and plaster backgrounds are helpfu l on smooth surfaces. Basically, the thick­ ness of plaster (total of undercoat plus finish coat) should lie between 1 5 and 65 mm. Fire resistance classes up to F 1 80-A can be achieved on steel stanchions. Acoustic plaster

Just like certain wall and soffit linings, acoustic plaster has a sound-attenuating effect that changes the room acoustics. Sprayed plasters with hydraulic binders and porous aggregates are frequently used. The resulting structure has a low impact resistance. The frequency range absorbed can be controlled by way of different system structures. This type of plaster can be appl ied to solid substrates or wood-wool slabs, for instance. Renovation plaster

Renovation plaster can be used to dry out damp, salt-laden masonry. The very large vol­ ume of air pores (> 40% by vol . ) enables the salts to crystallise within the plaster wh ile the water vapour evaporates to the outside without causing any efflorescence. Renovation plaster, 20 mm thick, can soak up about 2 - 6 kg of salt per square metre. In Germany a scientific-technical study group concerned with the preservation and refurbish­ ment of historical buildings (wrA) has defined renovation plaster generally as premixed dry materials for producing p lasters with a high porosity and water vapour permeabi l ity but at the same time a substantially reduced capil lary action. wrA datasheet 2-2-91 specifies further details.

Renovation plaster is made up of spatterdash, undercoat, renovation plaster and finish coat, with physical or chemical air entrainers added d uring mixing to reduce substantially the densi­ ty of the mix (containing cement or trass/lime) . Plaster as a heat storage medium

Micro-encapsulated phase change materials (PCM) can reduce summer temperature peaks when mixed into gypsum plaster or cement render for i nternal use. A 30 mm coat of plaster containing 30% PCM achieves a heat storage capacity equivalent to 1 80 mm of concrete. It is possible to influence the region of the phase transition in which the energy consumption of the paraffin capsu les takes place - normally 23-26°C. The stored energy is released again through night-time cooling. A coupling with active component cooling is possible in some cases. PCMs contribute to the thermal storage mass without adding any extra weight, but can­ not replace the thermal insulation. Insulating plaster

Besides its protective and decorative proper­ ties, insulating plaster also improves the ther­ mal i nsulation of a single-leaf wal l . This plaster consists of a water-retardant, thermally insulat­ ing undercoat and a water-repellent finish coat. According to D I N V 1 8 550 plasters with a theo­ retical thermal conduction val ue le ,;::; 0.2 W/mk are classed as insu lating plasters. Such a plas­ ter is produced using lightweight mineral aggre­ gates or expanded polystyrene and premixed "coarse stuff" with a m ineral binder (oven-dry density p < 0.6 kg/dm 3) . The total thickness of the multi-coat undercoat is 30-80 mm. The MG P I or MG P II finish coat is 8-1 5 mm thick. As this finish coat is very thin, its strength can be higher than the soft, thermally insulating

Typical applications

Water absorption Water diffusion coefficient! resistance W-value index [kg/m2mino.5)

[-)

>

I nternal and external for low loads; with addition of cement: external, water-retardanVrepellent I nternal for normal loads; with addition of cement: external, water-retardant

2.0 > 2.0 > 2.0 with add. < 0.5

20 20 20-30

mortar with masonry lime or mortar with render & masonry binder lime cement mortar

2,5

Internal with enhanced abrasion resistance, including wet interior areas; with addition of cement: external, water-repellent

< 2.0

20-30

2,5

External with enhanced abrasion resistance

< 0.5

1 5-35

10

External, basement walls, plinths

0.5

50

b

cement mortar with lime hydrate cement mortar

10

External, basement walls, plinths

0.5

50

P IV

a b c d

gypsum mortar gypsum sand mortar gypsum lime mortar lime gypsum mortar

2 2 2 2

Internal, corresp. to machine-applied (gypsum, bonding, ready-mixed) plaster 5.0-1 5.0 Internal approx. 1 8.0 Internal 5.0-1 5.0 5.0-1 5.0 Internal

8-10 8-1 0 5-6 5-6

PV

a b

anhydrite mortar anhydrite lime mortar

2 2

Internal Internal

n.a. n.a.

n.a. n.a.

P II

b P ili

a

P Org 1

synthetic resin mix, alkali-resistant

Internal and external on firm substrates improved with mineral and synthetic materials, water-repellent

0.1

1 00

P Org 2

synthetic resin mix

Internal

0.1

50-200 C 7.10

1 90

Surfaces and coatings

C 7 . 1 0 Plastering mix classes to D I N V 1 8550 C 7. 1 1 Classification of properties of solid mortar to D I N EN 998-1 C 7 . 1 2 Plasterwork surface finishes a floated b combed c felted d scraped e sprayed f scratched g exposed aggregate h sgraffito

Mortar properties to DIN EN 998

Category

Value

Compressive strength after 28 days [N/mm']

CS CS CS CS

0.4-2 .5 1 .5-5.0 3.5-7.5 ;;, 6

Capillary water absorption [kg/m'mino.5]

WO W1 W2

,; 0.4 '; 0.2

Thermal conductivity [W/mK]

T1 T2

,; 0. 1 ,; 0.2

I II III IV

a

C 7.1 1 b

undercoat because this does not transfer any stresses from the substrate. The complete plaster system must be adjusted in such a way that moisture absorbed by capil­ lary action cannot diminish the insulating effect. Thermal insulation composite systems

Manufacturers can supply coordinated compo­ nents that form a complete thermal insulation composite system. They should not be mixed with other components because this invalidates the guarantee. Thermal insulation composite systems are mainly used when the thermal insulation of a building is to be increased, e . g . during refur­ bishment work, or to avoid transferring stresses in hybrid constructions where changes of mate­ rial must be bridged over without cracks. Ther­ mal insulation composite systems improve the rainproofing of external walls and eliminate thermal bridges. They are self-supporting and can accommodate wind loads. A thermal insulation composite system consists of four layers: adhesive thermal insulation plaster with reinforcement finish coat Processing The adhesive forms a structural bond between insulating material and substrate. Additional fix­ ings and strips of aluminium or plastic may be required to hold the insulating material in place depending on type of substrate and wind loads. Thermally and dimensionally stable i nsulating elements not vulnerable to moisture fulfil the requirements for thermal insulation composite systems, e.g. expanded or extruded polystyrene foam, wood-wool slabs and m ineral wool (see "I nsulating and sealing", pp. 1 35-4 1 ) . The glass cloth embedded i n the 3-4 m m thick reinforcing layer accommodates shrinkage and thermal stresses, but also external mechanical actions. The thin finish coat of mineral or organ­ ic plaster provides the necessary weather pro­ tection.

Surface finishes of plaster work

The surface of a coat of plaster or render can be finished in many different ways. However, regional variations and the d iversity of earlier times have g iven way to commercially pro­ duced plastering mixes. Besides the method of application and the skills of the plasterer, pig­ ments and the size and nature of the aggre­ gates i nfluence the texture of the finish coat. Floated finish The surface of the hardened plaster is rubbed with a smooth float or a sponge float. The result is a fine, dense structure (fig . C 7. 1 2 a) . An enrichment of the binder at the surface can lead to shrinkage cracks. Comb-like tools can be used to decorate the surface (fig . C 7 . 1 2 b) . Scraped finish This finished is achieved by d isplacing the sur­ face directly after applying the plaster. This directional effect depends on the size of aggre­ gate, the surface finish of the tools used and the consistency of the mortar (fi g . C 7. 1 2 d ) .

c

d

e

Spray plastering Also known as projection plasterin g , this requires a fine-grain, fluid mix which is sprayed on by machine in several coats to achieve a finely structured surface. This inexpensive technique is also used for acoustic plasters (fi g . C 7. 1 2 e) . Scratched finish Once the plaster has achieved a certain strength, it is worked with a nail float or scraper so that, with a suitably graded aggregate, the larger grains are pulled out of the surface (fig C 7 . 1 2 f) . Exposed aggregate finish I n contrast to the scratched finish, the coarse aggregates, e . g . gravel or coloured fragments of glass, remain after washing away the binder laitance from the surface (fi g . C 7. 1 2 g) .

g

Sgraffito This involves cutting away a coat of plaster to reveal another coat of a d ifferent colour under-

1 91

Surfaces and coatings

Binders

The key ingredient that determines the proper­ ties of the finished coating is the binder. As a non-volatile component, it ensures that the coatin g is bonded to the substrate by way of adhesion, but it also bonds together the solid particles, e . g . pigments, fillers, by means of cohesion. Once applied to the substrate, the b inder changes its state physically or chemi­ cally. We distinguish binders according to the type of material (fi g . C 7 . 1 9) :

C 7.13

neath. I n principle, more than two layers, each with a different colour, can be employed . Three-dimensional patterns, figures, motifs and decoration of infinite variety can be created in this way (fig. C 7. 1 2 h). Scagliola This surface finish simi lar to stucco is produced from four coats of lime plaster. The two upper coats contain marble dust. After hardening, the surface is floated with a warm float and wax.

Coatings

In prehistoric times, long before structures were erected as shelters or for ritual purposes, people used coating materials in the form of fats, soot or coloured earths to add artistic dec­ oration to caves and ritual artefacts. The first coatings consisted of a binder and p i gments for colouring. As a way of protecting and decoratin g build­ ings, lime mixed with water has been appl ied to mineral substrates since about 4000 BC. Up until the Industrial Age, various substances such as oils, fax, plant resins, bone g l u e and animal proteins were used as the fixative bind­ er. The prime aim of this was to improve the weathering resistance and the compatibility with the substrate. Hardwearing and bright dyes remained pre­ cious commodities owin g to their scarcity, which meant that colour also took on a prestig­ ious character. Even painters mixed their mate­ rials in small q uantities to meet their require­ ments according to handed-down instructions. A binder based on water g lass was developed for coating facades at the end of the 1 9th cen­ tury and this proved to have a durabi l ity meas­ ured in decades. And by the start of the 20th century the chemicals industry was able to offer cheap alternatives to the inorganic pig­ ments in the form of the brightly coloured, sta­ ble, organic azo dyes. During the 1 950s, the advances in synthetic materials resulted in the production of binders for various tasks and substrates internally and externally.

1 92

C 7.14

Inorganic binders The inorganic binders include: ' l ime , cement , potassium water glass (silicate)

The tasks of coatings

The primary functions of coatings accord ing to EN 97 1 - 1 are as follows: Decoration - modifying or re-creating the substrate through colour, g loss and surface texture. Preservation - retaining the original condition of the substrate with respect to the aforemen­ tioned aspects as long as possible. Protection - keeping water, atmospheric, chemica l , biological, mechanical or other actions away from the substrate. Coating systems frequently satisfy all three tasks equally. I n order to sustain the value of a building com­ ponent and its functional ity, it must be main­ tained. As the applied coatings usually exhi b it a considerably shorter l ifetime than the compo­ nents and objects to be protected or decorat­ ed, their significance in ecological and eco­ nomic terms is considerable. Depending on its nature, a coating may be easily renewed or could even involve complete refurbishment of the building component concerned. The shorter l ifetime is partly due to the coat­ i ng 's d i rect contact with the environment, but also the durability of the constituents them­ selves, their compatibil ity with the substrate and their processing on the building site.

Organic binders Their technical development is closely entwined with that of the plastics industry, which suppl ies a vast range of chemical prod­ ucts. To ease a review of these materials, a basic classification is necessary:

Natural substances: Plant and animal resins and oils, e . g . colo­ phon ium, shellac, starch and l inseed oil. Modified natural substances: Boi led linseed oil, citrus oils and chlorinated rubber. Synthetic substances: These include alkyd resins, acrylic resins, copolymers, polyester, silicone resins, bitu­ men and chlorinated rubber, and account for the majority of organic binders these days. Solvents

Volatile organic compounds (VOC) (see "Glos­ sary", p. 269) d issolve other substances - in this case binders - without affecting them chemically. They g uarantee the appropriate viscosity and flow properties. Owing to their low boiling points, they volatilise during processing and escape into the air. Their toxicity is there­ fore critical, and appropriate precautions must be taken. Thresholds for their concentration in the air have been set and processing instruc­ tions must be followed.

Constituents

Coating materials essentially comprise binders, solvents, pigments, fillers and additives (fig. C 7. 1 5) . Functions and effects vary depend ing on the nature and proportions of the i ndividual components in the complex compo­ sition of the coatin g material. Owing to the dif­ ferent formulations of the manufacturers, a knowledge of the individual constituents of a coating material can ease the choice for a spe­ cific substrate. I n colloquial speech we speak of preservatives, paints, varnishes, stains and lacquers. Howev­ er, in terms of their properties and functions, these terms are only approximate. EN 97 1 - 1 defines the preferred terms.

Solvents are divided into the hydrocarbon, alcohol, ester and ketone groups: The aliphatic hydrocarbons include petrol ether, regular petrol, white spirit and mineral turpentine. Aromatic hydrocarbons (e.g. benzene) may no longer be used owing to their proven car­ cinogenic effects. Glycols are primarily used as a solvent in coating materials that can be thinned with water. Esters (e.g. methyl acetate) and ketones (e. g . acetone) form two further groups. In Germany the Federal Environment Agency prefers low-VOC coating materials and awards

Surfaces and coatings

the "Blue Angel" mark to products with an organic solvent content < 1 0% , provided other conditions are also fulfilled (e.g. Iow in hazard­ ous substances and preservatives) . Pigments

Colouring substances are divided i nto insoluble pigments and soluble dyes. The colours in coating materials are achieved exclusively throug h pigments. In addition, the pigments can also protect the substrate against ultraviolet radiation and corrosion. We divide pigments into four groups: Natural inorganic pigments (coloured earths, stone dust) such as chalk, ochre, umber are non-toxic, light-fast and weather-resistant. Natural organic pigments such as indigo are less light-fast and less weather-resistant; in a modified form indigo is also used as a dye. Synthetic inorganic pigments made from the oxides of titanium, iron, chromium and zinc exhibit good resistance to chemicals, good light-fastness and good covering power, but only minimal brill iance; they are suitable for almost all coating materials and substrates. Synthetic organic pigments are based on fossil raw materials; their large variety of col­ ours and good bri l l iance is often offset by limited light-fastness and weathering resist­ ance; negative i nteractions with binders and substrates are also not unknown. The majority of pigments used today fall into the last two groups. Fillers

The addition of stone d ust, e . g . from kaolin or feldspar, lend the coatin g su bstance and hard­ ness. They fill pores and small irregularities. The addition of, for example, polyamide and mineral fibres can reduce the risk of cracking. Additives

Further chemical substances can improve, for example, durability, and also workability by ensuring a certain viscosity; furthermore, they influence the later appearance of the coating despite being added in small amounts only. The designations of additives reflect their func­ tions: preservative, emulsifier, wetting agent, dispersant, stabi l iser, anti-foaming agent, pesti­ cide, desiccant, plastic iser, UV absorber. The effects of these substances must be checked individually to rule out any undesirable effects.

Classification of coating materials

Normally, coating materials are delivered to the building site in a liquid state ready for use. This state is generally achieved in one of two ways, which in turn influences the workability and also the properties of the finished coating:

acrylic resin dispersed in water chromium­ titanium yellow

Substances

kaolin e.g. dispersant, preservative

Solutions

Binders in solution are presented in the form of very homogeneous molecular d istributions within volatile, organic solvents. The pigments and fillers float in this binder solution. On prob­ lematic substrates they adhere better in the form of d ispersions because the smaller molec­ ular particles result in better penetration capac­ ity and wetting ability. Moisture or low tempera­ tures d uring the drying phase do not have any significant effect on the process. The finished coatin g exhibits a high density and good resist­ ance to external actions. Evaporation causes solvents to be released, some of which may be hazardous for humans or the environment; legislation therefore limits or prohi b its the use of these materials, e . g . aro­ matic hydrocarbons. Solvent-free coating mate­ rials represent the long-term goal. Newly developed polymer materials enable the conversion of, for example, acrylic or alkyd res­ ins to the aqueous state. The finished coating cannot be d istinguished from conventional products.

based on polymer dispersion

Application Phase transition

I

Coating C 7.15

C 7 . 1 3 Two-part coating o n p lywood, Flagship Store, New York, USA, 2003, Asymptote C 7 . 1 4 Floor coating based on epoxy resin, central trans­ former substation, Salzburg, Austria, 1 995, Betrix & Consolascio C 7 . 1 5 Composition of coatings C 7 . 1 6 Light permeability of coating materials a opaque b glaze coat c transparent C 7. 1 7 How coating materials work a preservative b primer c coating C 7 . 1 8 Proportions of substances in different coating systems

Dispersions

Coatin g materials thinned with water consist of an aqueous phase containing finely distributed liquid drops of binder in the form of a suspen­ sion. The pigments and fillers are d istributed in the water. Dispersions are inexpensive and environmentally friendly, and also present no problems during transport, storage and pro­ cessing. Damp substrates are easy to wet. However, dispersions are not sufficiently rain­ proof d uring application and req u i re tempera­ tures > 5°C during the drying phase. The bind­ er particles are larger and this fact reduces the penetration capacity, and more care is general­ ly req uired during application than is the case with products containing solvents. Although generally referred to as emulsion paints, it is better to use a more precise form of designation, e . g . d ispersions based on poly­ mer binders (acrylic resin, alkyd resin, etc . ) . Film formation, hardening, drying

In the liquid state the binder of the coating material is present in a d issolved or dispersed state in order to wet the substrate completely, bond loose particles, penetrate the pores of the building material and achieve a constant coat­ ing thickness. After application, the phase tran­ sition to the solid state takes place in two differ­ ent ways. The coatin g material becomes the coating:

1 00

a

b

c

C 7.16

a

b

c

C 7. 1 7

]

1

Cl

Q) > :g � Q)

0c:::=:=J

-

.s

co

co 0 u Q) N '"

8 rn

t ·c

'" Q) 0. co N E

a

�

Binder Filler

c=::J c:::::::J

Pigment Solvent C 7.18

1 93

Surfaces and coatings

Binders for coating materials Organic materials

Inorganic materials calcium hydrate

Natural materials

Modified natural materials

Synthetic materials

cement potassium water glass (silicate)

plant resins:

colophonium copal resin dammar

resins of animal origin:

shellac

vegetable/animal glues:

starch gelatines protein (casein)

vegetable/animal oils:

triglycerides: linseed oil soya oil waxes

cellulose nitrate

alkyd resins

(co)polymers:

boiled linseed oil

acrylic resins

vinyl acetate

citrus oil

unsaturated

vinyl chloride

colophonium-glycerine ester

polyester

butadiene

chlorinated rubber

epoxy resins

styrene

polyurethanes

acrylate

The physical hardening and film formation take place by way of evaporation of the sol­ vent, or the emulsion water in a dispersion. The chemical wetting and film formation of the binder take place by oxidising with con­ stituents in the air (curing), or through a reac­ tion between two binder components. It is often the case that both forms of hardening occur; for example, potassium water glass hardens as the water evaporates and carbon dioxide from the air is absorbed. The type of binder used governs whether or not a film is formed. Coating system

I n order for a coating to achieve the desired effect on a given substrate, it must be built u p in several - coordinated - layers which perform different functions: The primer ensures an adhesive bond between the coating system and the sub­ strate by bonding loose particles and reduc­ ing the absorbency. The undercoat must be compatible with the primer in a way that g uarantees the cohesive bond between the layers; it achieves the required layer thickness and a consistent

chlorinated rubber cyclised rubber silicones C 7.19

bitumen

surface finish, and may be opaque and/or coloured. The finish coat protects the coats below against external influences and also deter­ mines the degree of g loss finish. Thin coats dry better. Several coats may be necessary i n order to achieve the req ui red final thickness and the appropriate durability of the system. Properties such as the form of application on the substrate, the composition of the coating material, hardening process and l i g ht permea­ bility form a functional relationship that can be expressed in the following classification: Preservative A preservative contains a high proportion of solvent or water and l ittle binder. Without pig­ ments and fillers it seeps into the pores of the building material by capi l lary action and forms a thin layer. In the form of a primer, preservatives have the task of reducing the absorbency of the sub­ strate and neutralising it in chemical terms. If the preservative includes active substances, it can assume a protective function. On finished surfaces such as plaster/render, fair-face con-

C 7.21 1 94

crete, masonry or timber, preservatives contain­ ing silicone resin as the binder are water-repel­ lent (hydrophobic). Glaze coat The higher binder content ensures the forma­ tion of a transparent film on the surface. The low pigment content provides protection against ultraviolet radiation but usually allows the underlying substrate to remain visible through the film. The coating thickness and building performance properties of a g laze coat vary when used externally on timber depending on the binder content and the inclusion of a pesti­ cide. One-part coating A one-part coating material contains approx. 50% non-volatile substances that form an opaque, protective layer on the surface of the component following physical or chemical hard­ ening. High-solids products contain more sol i d particles and < 50% volati le components. Two-part coating Two liquid binders - base and hardener - react to form an extremely hardwearing film. Solvents reduce the viscosity to improve workabil ity.

C 7.22

Surfaces and coatings

Normal ly, coating materials are classified accord ing to the type of binder because this has a crucial effect on the characteristic prop­ erties of the resulting coating system.

development of the two-part coating material. The addition of synthetic d ispersions improves workability, adhesion and elasticity. In terms of suitable substrates and the curing process, this product is identical with the two-part product, but the diffusion capacity is lower.

Lime

Alkyd resins

Lime in the form of calcium hydrate (Ca(OH) 2 ) ' mixed with water, hardens through evaporation of water and absorption of carbon d ioxide from the air to form calcium carbonate ( l imestone, CaC0 ) . The process is reversi ble and there­ 3 fore has ecological benefits. Small amounts of other binders such as polymer dispersions or casein improve the low weathering resistance. Calcium hydrate can bind only small quantities of pigment, which means that only pastel hues are normally possible. Coating materials based on calcium hydrate are used on mineral substrates. They are char­ acterised by a high d iffusion capacity and are easily repainted. However, they req u i re consid­ erable maintenance when used externally and are not particu larly hardweari n g .

Fatty acids react with g lycerine to form alkyd resin. Dissolved in a solvent or - a new devel­ opment - in water, this forms the basis for a number of coatin g materials to which virtually any other components can be added. There is also the possi bility of modifying the properties by combining the resin with other binders. Coatin g materials based on alkyd resin are often referred to as varnishes. After the solvent has q uickly evaporated , they undergo oxidation with the oxygen in the air and form a film. They are mainly used for dimensionally stable timber components and to prevent corrosion of iron and steel . They have proved to be unsuita­ ble for building materials with a cement binder because the addition of water leads to saponifi­ cation. Application and maintenance are sim­ ple.

Coating materials

Silicates

The two-part coating material consists of potas­ sium water g lass (K Si0 ) as the binder for 2 3 inorganic, water g lass-resistant pigments and fillers. Mixing the components with water is car­ ried out shortly before applying the coatin g to the surface. When applied to mineral sub­ strates that exhibit s i l icification, the coating material reacts with the carbon d ioxide in the air, the lime in the fil lers and the lime in the sub­ strate. The result is a hard , l i ght-fast and weath­ ering-resistant layer with a high d iffusion capacity which hardly reduces even after recoating. Owing to their alkalin ity, silicate coatings act as germicides. I n conjunction with the slight chalking tendency, treated surfaces appear clean for many decades. This coating material is primarily suited to facades. Old coatings can be painted over with the same material, but not with coatings that form a film. The one-part coating material based on water glass is supplied ready to use. This is a further

Acrylic resins

Acrylic resin binders are provided in the form of a d i spersion in water. Mixed with inorganic pig­ ments, and generally known as (synthetic) acrylic paints, this coatin g material is the most popular system for external use on mineral sub­ strates. The film formation takes place physical­ ly through the evaporation of the aqueous phase, and the coatin g adheres to the sub­ strate. The advantages of coating materials based on acrylic resin are their easy workabili­ ty, the numerous architectural options and the wide range of applications. Depending on the binder combination and the solvent used, the surface finish varies from elastic to tough and impact-resistant. The water vapour d iffusion decreases as more coats are applied. Polymer resins

The combinations of polymer binders (e.g. acr­ ylate, styrene, vinyl acetate, polyvinyl chloride) are provided dissolved in a solvent. Owin g to

their smal l molecules, they penetrate deeper into the substrate than a binder dispersed in water. They form a dense film as the solvent evaporates. This hardwearing coating is an ideal solution for protecting difficult concrete substrates (owing to the low carbon dioxide permeabi lity) as well as mineral substrates and hot-dip gal­ vanised steel parts. Epoxy resins, polyurethane resins

These two-part coatin g materials consist of an epoxy or polyurethane resin base (dissolved in a solvent) plus a hardener. The two compo­ nents are mixed in an appropriate ratio immedi­ ately before use. The chemically reactive set­ ting process limits the workin g time (pot l ife) . Applications include the factory coating of tim­ ber surfaces for internal use, and concrete floors. The high resistance to mechanical and chemi­ cal effects is offset by the low vapour permea­ b i l ity and the sensitivity to moisture on mineral substrates, plus the yellowing tendency when used externally. Two-part coating systems based on poly­ urethane resin are better than epoxy resin sys­ tems in terms of toughness, wearing properties, UV l ight resistance and universal suitability for many well -used surfaces internally and exter­ nally. Silicone resins

Sil icone resins are dispersed in water and mixed with a small quantity of organic solvents and synthetic dispersions. This coating material dries through evaporation of the water and l i ke the sil icates - through a reaction with an alkaline substrate. Coatings based on silicone resins have an elastomeric character plus high thermal stability and chemicals resistance. They are good at repelling water but are vapour-permeable and are also used as a pre­ servative. The product quality fluctuates depend i n g on the manufacturer because there are currently no standards that specify the q uantities or proportions of the constituents.

C 7 . 1 9 Systematic classification of binders for coating materials C 7.20 Polyurethane resin coating, private house, Vienna, Austria, 2002, Querkraft C 7.21 Coil coating on sheet steel, private house, Pomponne, France, 2002, Marin, Trottin C 7.22 Glaze coat on timber behind cast glass, kinder­ garten, Reutlingen, Germany, 2001 , Ackermann, Raft C 7.23 Private house, Pessac, France, 1 936, Le Corbusier a no passive facade protection, total lack of maintenance b after refurbishment a

b

C 7.23

1 95

Surfaces and coatings

Coating technique depending on specific state of coating material

Liquid state

hot dipping

•

•

Granular or powder state

for workpieces without enc­ losed voids, coating material drains away galvanising, tinning of wires, sheet metal, profiles

painting lacquering

(see "Method of application", p . 1 97)

pouring

e.g. for sealing floors

Natural resins (oils, waxes)

The natural resins from animal and vegetable oils, resins and waxes, e . g . l inseed o i l , copal resin or beeswax, vary considerably. These binders are used in combi nation and often in a chemically modified form. Solvents rarely enhance the workability. The applications and properties vary considerably depending on the components. Although product names contain­ ing terms like " b io" or " natural" imply healthy contents, the coating materials with such des­ i gnations are just as likely to include hazardous substances as well owing to their chemical composition.

Performance features

EN 1 062 divides coating materials (for mineral substrates and concrete) into performance groups irrespective of the binder. This classifi­ cation concentrates on the building perform­ ance properties that a coating material must exhibit in order to fulfil the req uired functions for a given substrate. The parameters listed in the standard are important for all substrates: gloss (G) : full gloss, semi-gloss, matt dry coat thickness (E) : in five classes, � 50 to > 400 IJm particle size (S) : fine, med i u m , coarse, very coarse, � 1 00 to > 1 500 IJm

plastering rendering

(see "Plasterwork", pp. 1 88-192)

whirl sintering

requires hot workpiece so that sprayed thermosetting powder coating forms coherent covering

Ionised state

particles are distributed evenly by an electric field between spraying equipment and metal part

electroplating

thermal spraying

coating material (metal, ceramic) is melted upon spraying

chemical coating

water vapour d iffusion (V) : low, moderate, h i g h , � 1 5 to > 1 50 g / m2d water permeability (W) : low, moderate, high crack-brid g i n g (A) : 0 to > 2500 IJm carbon d ioxide permeability (C) The above parameters enable us to assess whether a given coating material is suitable for a given substrate. This is made clear by taking some parameters as an example.

(see "Corrosion protection", p. 78)

C 7.24

q uality that specify only tendencies must be verified with figures. Wet-scrub resistance

One of the features specified in EN 1 3300 , which covers water-based coating materials for inter­ nal walls and soffits, is the wet-scrub resist­ ance, which it d ivides into five classes; class 1 materials have the best resistance to wet scrub­ b i n g . This standard replaces D I N 53 778 in which the washing or scrubbing resistance was defined.

Dry coat thickness (E) [Ilm]

The coat thicknesses and surface textures are based on the manufacturer ' s information and depend on the method of application. They can i nfluence the building performance properties because in some cases the diffusion resistance increases with the thickness of the coat. Water vapour diffusion M

The V-value in g / m2d (also known as the rate of evaporation) specifies how much water vapour d iffuses through 1 m2 of coating in 24 hours at 23°C. The higher the V-value, the better is the water vapour diffusion, i . e . the V-value meas­ ures the rate at which the substrate dries out through the coatin g system . This is noticeably slower than the capillary water absorption. The coating is a good moisture regulator when the building components can dry out. Water permeability (W)

=

Carbon dioxide permeability (C) [Sd cOJ

Carbon dioxide neutralises the anti-corrosive alkaline environment of the steel reinforcement in concrete. If the carbon d ioxide permeabil ity of the coating is low (the sd -value [C0 ] high), it 2 helps to prevent carbonation. Manufacturers' data sheets must include the above parameters. All statements regard ing

1 96

spreading

electrostatic coating

The W-value specifies how much water pene­ trates through 1 m2 of coating during 24 hours of rainfall (e.g. on a facade) . The unit of meas­ urement kg / m2W5 means that with a W-value of 1 .0, the substrate absorbs approx. 5 I of water, and when W 0. 1 , only 1 /1 0 of this. Good coatings have low W-values, i.e. they allow very little water to pass through to the substrate.

C 7.25

Plastic state

Application

Prior to applying a coating it is essential to assess the state of the substrate . Further meas­ ures and the choice of coatin g system depend on the outcome of this assessment. I nspection of the substrate reveals whether the strength is adequate, and whether crackin g , areas with large pores, rust or old, poorly adhering coat­ ings are present. Constructional deficiencies and excessive moisture in the substrate can render a coating ineffective. Preparing the substrate

The substrate must be properly prepared in order to reach a cond ition that is suitable for the intended coating. The following methods remove the surface of the substrate: flame cleaning, hig h-pressure water jets, m i l l i n g , compressed-air jets, shot peening, wet blasting, also brushing and grind­ ing. The chemical treatments include washing with acids and wetting agents, which are sub­ sequently rinsed off and neutralised. I ndustrial­ ly manufactured steel and plastic semi-finished goods are sometimes provided with a coating that must first be removed, likewise the layer of scale that forms on l ime plasters. The debris must be separated from any blasting media used and d isposed of properly. Once the surface has been prepared, it may be necessary to apply a primer to enhance the bond with the subsequent coating and/or to create a firm surface.

Surfaces and coatings

Methods of application

primer and the steel surface.

Coati ngs are applied manually - both in the

The dry coating thickness of the total system

1 60 to 320

factory and on a b u i l d i n g site - i n the l i q u i d

varies from

state with brushes, rol l ers, sponges, or b y

corrosion load g iven i n D I N E N ISO

pour i n g . Spraying equ ipment - compressed-air

i n s i g nifi cant t o C5 very severe ) .

IJm depending on the

1 2 944

(C1

or airless spray guns - improves the u n iformity of the coating thickness and avoids the charac­

Galvanising

teristic surface textures of the other forms of

The thickness of the protective layer of zinc

application. The position of the b u i l d i n g com­

varies depen d i n g on the form of galvan i s i n g ,

ponent plays an im portant role; when a p p l i e d

and decreases over t h e years a s t h e z i n c cor­

to a vertical surface, t h e viscosity o f t h e coating

rodes. The d urab i l ity depends on the aggres­

material must be h i g her than for a horizontal

siveness of the local conditions. We d isti n g u ish

surface.

between three types of galva n i s i n g :

Besides the manual methods, there are also ind ustrial methods i n use, such as spraying in

Hot-d i p galvanising is carried o u t i n a bath of

enclosed booths with extraction systems, which

z i n c heated to approx. 450°C into which the

prevent operatives being exposed to excessive

object to be galvanised is briefly immersed;

amounts of solvent ( e . g . i n the automotive

this form of coating is the most durable and

industry) . Powder coating involves applying an electric

can be u p to 1 00 IJm thick. Strip galvan ising with subsequent polymer

current to the component and covering with a

fi nish coat (coil coati n g ) is used for many

solvent-free coating material (fi g . C

7.24) .

semi-fi n i shed sheet steel products.

I n the d u plex method metal parts are i n itially

Electrogalva n i s i n g is based on the electro­

hot-dip galvanised and then coated afterwards.

chemical deposition on the component of the

For radiators, for exam ple, this then avoids the

dissolved zinc i n the form of ions.

need for painting on site. The d u p lex method improves the qual ity and avoids solvent emis­ sions.

After removing the layer of oxide caused by the manufacturing process, the d u p l ex system enables an add itional polymer finish coat to be applied which i ncreases the service l ife of the

Coating materials for specific substrates

galvanised component. Suitable coat i n g s are

Iron, steel

resin or two-part products based on epoxy and

Atmospheric corrosion is a reaction between

polyurethane res i n s .

physically dry i n g b i n ders based on acrylic

iron (Fe) and oxygen (02) in the presence of water, and forms iron oxi d e (Fep3) ) ' Airborne

Wood a n d wood-based products

pollutants or salts ( e . g . at the coast) accelerate

Wooden win dows and doors are dimensionally

the rusting process. Coating is the most com­

stable components made from carefu lly select­

mon way of protecting steel surfaces. Although

ed tim ber. Loadbearing assemblies, external

polymer su bstances form a dense f i l m , water

wal l cladd i n g s and formwork are not dimen­

and oxygen can sti l l defuse thro u g h them;

sionally stable and may develop shrinkage

therefore, more ela borate measures such as

cracks and und ergo d i stortion, and this may

galvan ising or chemical passivation are neces­

affect any coat i n g s applied beforehand .

sary. All the methods req u i re careful planning

I mpregnation with preservative, which pene­

to avoid crevices and joi nts i n the b u i l d i n g

trates deep into the substrate, prevents water

component, t o provide rounded e d g e s and

absorption by cap i l l ary action.

welded seams, and to exc lude galvanic corro­ sion due to contact with other metals.

Passive preservation The priority for external appl ications l i es with

Chemical passivation

passive timber protection measures. The spe­

Chemical passivation is provided by the primer

c i es of wood, the moisture content d u r i n g

because only this has d i rect contact with the

insta l l ation, overhanging eaves, ventilation o n

steel. Here, zinc dust is the rustproof p i gment

all sides, covering o f horizontal surfaces

used as a sacrificial anode (with a cathode

exposed to the weather, adeq uate c learance

effect) . As zinc is lower down the electroc hemi­

between timber and soi l , and the avoidance of

cal series than steel , an electroc hemical neu­

pon d i n g all help to increase the durabi l ity of

tralisation takes place so that there is no reac­

timber components. However, such passive

tion between the steel and its envi ronment.

measures cannot prevent insect attack.

Zinc phosphate p i g ments have a passivating

U ntreated tim ber exposed to the weather will

effect. Environmentally hazardous rustproofing

grad ually take on a grey colour owi ng to the

pig ments such as red lead are pro h i b ited i n

effects of ultraviolet radiation and the recurring

Germany.

cycle of wetting and d ry i n g . If the component is

Binders such as epoxy, acrylic and alkyd res­

essentially protected against rai n , it will not suf­

ins d ispersed i n water or d i ssolved i n solvents,

fer, merely show its age and assume its grey

also polyurethane and chlori nated rubber, form

patina.

C 7.27

C 7.24 Systematic classification of coating application techniques based on D I N 8580 C 7.25 Powder-coated, high-gloss, curved metal surface C 7.26 Timber coating containing gold pigment, "Toten­ stube", Vrin, Switzerland, 2002, Gion Caminada C 7.27 Concrete facade treated with hydrophobic coat­ ing, factory, Ebermannsdorf, Germany, 2003, Francoise-Helene Jourda C 7.28 Lime coating popular in Med iterranean countries

the protective fi l m . Undercoat and f i n i s h coat prevent corrosion stimulators from reac h i n g the

1 97

Surfaces and coatings

Chemical preservation When treating timber with chemical preserva­ tives we distinguish between penetration of several centimetres, penetration of just a few millimetres, and a surface coatin g . Pressure impregnation , thermal impregnation and immersion methods are available for the first two forms. A surface coating usually takes the form of a primer (for enhancing bond and reducing ab­ sorbency) , an undercoat and a finish coat. All edges and corners of timber components should be chamfered so that the coatin g material has the chance to form a uniform film here, too.

Water-based coating materials with an acrylic resin binder are suitable for this form of surface protection. However, their thermoplastic prop­ erties increase the maintenance req u i rements. Alkyd resins are easier to renovate, but require more careful application. The following rules of thumb are valid for the maintenance intervals of coatings on timber: Opaque coatings prevent the photo-oxidation of lignin in the timber better than glaze coats. Dark colours contribute to a greater tempera­ ture rise in the timber and hence g reater expansion. Hydrophobic coatings prevent rapid altera­ tions of the timber's moisture content. Wood-based products req u i re d iffusion-proof edge trims in order to prevent swelling or delamination of the individual plies.

Coatings for facades of masonry, concrete and render are d ivided into water-based systems ( based on lime, silicate or silicone resin binders and polymer dispersions) and solvent-based systems (based on polymer resin). Plasterwork Plasters and renders rich i n lime (MG P I ) set very slowly by absorbing carbon d ioxide. Coat­ ings based on silicate or silicone resin, which are open to diffusion, assist this process. Poly­ mer dispersions are also possible with MG P I I and I I I mixes. Two-part silicate coatings are not suitable for gypsum plasters of group MG P IV because the s i l icification reaction of the coating material cannot take place with this type of substrate. Concrete Good-quality reinforced concrete components exposed to the weather requ i re l ittle protection because the abrasion resistance and vapour­ tightness of the concrete i ncreases with its compressive strength. The alkal ine environ­ ment of the concrete protects the steel rein­ forcement against corrosion. Acids from the surroundings, which in an aqueous or gaseous state can i nfi ltrate concretes of lower qual ity, reduce the pH value and cancel out the protec­ tive effect (carbonation ) . Fine cracks in the ten­ sion zones of reinforced concrete components offer additional opportunities for such sub­ stances to infiltrate. In order to prevent carbon­ ation and to bridge over any cracks, new con­ crete can be coated with acrylic resin, bitumen

or epoxy res i n , all of which adhere excellently to the concrete. Later, during refurbishment of the concrete, there is the opportunity to apply hydrophobic impregnation treatments based on silicone resin - provided the pore structure of the concrete permits some penetration. Sys­ tems based on acrylic resin or copolymers can be used as opaque coati ngs or g laze coats for decorative purposes. Aluminium

Owing to their low weight and good durabil ity, aluminium components are used in many areas of building, e . g . facades, windows, cladding. Untreated aluminium is not sensitive to mois­ ture or the oxygen in the air because it quickly forms a dense coatin g of protective oxide. Anodic oxidation in the factory creates a more uniform and stronger layer of oxide compared to uncontrolled ( i . e . natural) oxidation, the col­ our of which can also be influenced. This so­ called anodising enables the aluminium to g l is­ ten in metallic colours ranging from silver to dark bronze. As a rule, the aluminium then requires no further surface treatment. However, this is advisable during refurbishment work. But there may also be architectural reasons for giv­ ing aluminium a further transparent or opaque coating. To do this, a powder coating based on polyurethane resin is applied to the anodised aluminium at the factory. The necessary adhe­ sion for the coating must be achieved through roughening the surface by means of dry blast­ ing with a fine, solid blasti n g med ium, or by grinding, rinsing and cleaning with a solvent.

Coating thickness and degree of pigmentation are crucial parameters for the durabi l ity - pig­ ments, for example, absorb ultraviolet radiation. The constituents of wood and its hyg roscopic behaviour, which varies with the species, can also influence the durability of a coating. Basic­ ally, less durable species of wood req u i re maintenance at more frequent intervals. I nternal timber components not subject to any severe loads do not require any chemical pre­ servatives. Mineral substrates

M ineral su bstrates are d ivided into m ineral plasters/renders to D I N V 1 8 550 and other plasters/renders, calcium silicate, ceramic materials, natural stone, concrete, aerated con­ crete and cement-bonded or gypsum-bonded boards. In the case of materials with a m ineral binder, we d istinguish hydraulic (lime) and eminently hydraulic (cement) binders from non-hydraulic binders (high-calcium lime, gypsum) . The d if­ ferent settin g processes and the building per­ formance properties of the materials determine the coating system.

C 7.29 Different degrees of gloss finish and substrates, Van Royen Apartment, London, UK, 1 986, John Pawson C 7.30 Parameters and possible applications (typical values) of coating materials C 7.29

1 98

Surfaces and coatings

Two or three coordinated coats g uarantee pro­ tection. The primer forms a film and consists of materials based on acrylic, polymer or alkyd resin. Undercoat and finish coat can contain the same binder. Epoxy resin is used for more demanding situations. Polyurethane resins ensure very good protection against chemicals and weathering. Synthetic materials

Synthetic materials require surface protection only in exceptional circumstances, e . g . in the case of low light-fastness, or to improve the chemicals and weatherin g resistance. How­ ever, plastic components are frequently coated for reasons of appearance. Owing to the variety of products on the market, on the building site it is often very difficult to establ ish which type of plastic is involved, but the choice of coatin g system depends precisely on this factor. It is difficult to coat synthetic materials because their smooth, dense surfaces exhibit no polarity, which means that adequate adhesion between primer and substrate is lacki n g . In addition, electrostatic charges attract dust, and release agents from the production and migration of auxiliary substances prevent a permanent coat­ ing. For these reasons, preparation of the sub­ strate is critical, and this is basically only possi­ ble in an industrial environment. The three coats consist of a two-part primer based on polyurethane plus undercoat and finish coat of two-part acrylic or polymer resins. The high coefficient of thermal expansion of syn­ thetic materials normally call for light colours

Coating material according to binder

.

.

0 1

2

Contains solvents?

Water vapour diffusion resistance

because otherwise the components distort too severely.

time. Once provided with an approved fire­ resistant coatin g , internal wood and wood­ based products can be classed as not readily flammabl e (B 1 ) instead of flammable ( B 2 ) . The fire resistance class of load bearing internal and external steel components can be improved from F 30 to F 60 according to DIN 41 02-2.

Coatings for special purposes

New technologies enable the production of complex coatin g materials for satisfying special tasks. The important thing here is that the com­ plete system from substrate to finish coat must be considered as a whole in order to avoid just one desirable q uality causing innumerable building performance problems.

Water-repellent coatings

Generally, the surfaces of building materials are hydrophilic with respect to water, i.e. they attract water, dependi n g on the contact angle of the water with respect to the building mate­ rial. Where this is < 90°, the liquid is absorbed by capillary action. Hydrophobic (water-repel­ lent) substances appl ied to the surface of the building material themselves seep into the cap­ i llaries and increase the contact angle to > 90°. In this way they prevent the wetting with water and absorption. Water incident on the surface runs off in droplets and washes away particles of dirt which cannot adhere to the surface. Hydrophobic treatments take the form of impregnation. But they last only a few years and must then be renewed . Masonry c a n b e dried out with hydrophobic injection treatments that act like a horizontal damp-proof course. Hydrophobic treatments do not close off the pores of the building component and remain permeable to water vapour, but cannot with­ stand hydrostatic pressure. As they are trans­ parent and permeable to ultraviolet radiation , they therefore cannot prevent the formation of the grey patina on timber surfaces. Water- and

Coatings for fire protection

D I N 4 1 02-1 c lasses building materials accord­ ing to their combustibility and behaviour in fire, and places them in various categories - from A 1 (incombustible) to B 3 (highly flammable) (see "Glossary", pp. 265-66) . Additional meas­ ures to protect components against fire, e . g . fire-retardant coatings, may be required depending on regulations or the actual risks. Such coatings consist of water-based d isper­ sions on a polymer basis or solutions of acr­ ylate resins, with or without pigments. Additives made from a carbon source, a catalyst and a propellant can form a layer of insulation and thus have a fire-retardant effect. The dry coat­ ing thickness on the component is 200-2000 IJm. Once the ambient temperature climbs beyond 200°C, the additive reacts and foams up. A porous (temporarily thermally insulating) , car­ bon-based layer up to 50 mm thick then pro­ tects the component for a certain length of

Abrasion resistance

Applications according to substrate timber

mineral materials

internal and external internal only limited suitability Does not contain solvents; the values for natural resin coatings containing solvents are considerably higher. with appropriate primer

2 if) <1l 0. Q) £

Q) E Q) u

ID Ci5 <1l 0. E ::J if) Q. >CJ1

ID "0 c [I!

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no

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1 -part sil icate, dispersant

no

60-800

high

·

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. 2

. 2

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2-part silicate

no

40- 1 50

high

·

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02

0

·

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no

80- 1 50

moderate

·

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no

1 00 - 5000

high

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·

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if)

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synthetic materials

metals

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partly

< 1 00 '

high

·

Oil

partly

1 000- 5000

very high

·

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Alkyd resin

yes

1 2 000-25 000

very high

·

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2-part epoxy resin

yes

1 0 000-40000

very high

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yes

25000-35 000

very high

Silicone resin

partly

50- 600

high

·

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very high

0

·

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Polymer resin

yes

1 00-1 500

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C 7.30

1 99

Surfaces and coatings

C 7.32

C 7.31

solvent-based systems make use primarily of silicon organic compounds. Anti-graffiti coatings

The effect of these coatings is to prevent any form of soiling - not just malicious graffiti adhering to the surface, thus makin g atmos­ pheric deposits and spray paint easy to remove. The complete system consists of a sin­ gle- or multi-coat preventive coating with prim­ er and separating layer, a chemical c leaning agent, which dissolves the soiling, and hot­ water high-pressure cleaning equipment to rinse away the dirt, dust, paint and cleaning agent. In order to enable the rinsing of the surface, the anti-graffiti coating creates a non-polar surface. This is achieved with coating materials - nor­ mally based on fluoride polymers - that func­ tion in a similar way to the Teflon coating on cooking utensils. The film of coatin g material is transparent and scratch-resistant.

Wallpapers and stretch coverings

Materials for lining the walls are primarily pro­ vided for decorative purposes. But they can help to absorb sound and also provide some thermal insulation. During the Renaissance, leather or fabrics were stretched between poles and battens. Starting in the 1 9th century, paper wallpapers designed to imitate oil paint­ i ngs were pasted over the entire wal l . Modern wall lining materials include wal l papers, cover­ ings of synthetic materials or cork, and textured underlays for coatings and stretch coverings (fig. C 7 .34) . A s wallpapers and stretch coverings cover large areas internally, their diffusion and absorption behaviour has a considerable influ­ ence on the interior climate. Therefore, l i ke coatings, they must be coordinated with the complete wall system in order to guarantee its proper functioning.

200

Apart from declared exceptions, wallpapers are suppl ied in standard metric rolls (eurorolls) which measure 1 0.05 x 0.53 m . Besides defined codes for manufacturing and processing pro­ perties, the following features are relevant: Polymer add itives increase the wet tearing strength. Treating with fungicidal substances protects against mou ld growth. I mpregnation achieves washing and scrub­ bing resistance. A special chemical preparation makes wall­ papers not readily flammable. Synthetic materials in and on wallpapers reduce their d iffusion capacity.

C 7.33

ric and textured wallpapers require special pastes based on methyl cellulose with dis­ persed polyvinyl acetate, which reduce the diffusion capacity and have a detrimental effect on the interior climate. Stretch coverings

The indirect method involves fixing the fabrics to the substrate by way of tacking, nailing or g l u i n g . This leaves no cavity between covering and substrate and so the substrate must be properly prepared. The direct method enables non-twist stretching of the fabric using battens and concealed fixings which are easy to re­ move for cleani n g . These coverings attached at a small d istance from the wall have a positive effect on the room acoustics.

Paper wallpapers

A single-layer, non-printed paper wallpaper without add itives represents the wall covering most open to d iffusion and with the lowest emissions. Embossing gives the appearance of a synthetic wal l paper. Wood chip wallpapers

These are produced from one or two layers of paper containing a high proportion of recycled paper. Fibres of wood or recycled paper are evenly distri buted between the layers or embedded directly in the paper mass. Vinyl wallpapers

Expanded or solid synthetic material is applied over the whole area of a paper, fabric or syn­ thetic backing. Owing to the risk of mould g rowth beneath the wal l paper, some vinyl wall­ papers include a fungicide. These wallpapers have a poor d iffusion behaviour (fi g . C 7.32) . Adhesives for wallpapers

Wallpaper pastes are normally based on methyl cellulose, or starch as an alternative. The adhesion of such pastes is usually ade­ quate for the majority of wallpapers appl ied to dry, absorbent substrates. However, vinyl, fab-

Patterns

The reaction to the functionalism of wood chip wallpapers saw the appearance of wallpapers with floral and large geometrical patterns in bold colours during the 1 970s. These days, youn g designers devise new wall lining con­ cepts such as the "Single Wallpaper" (fig. C 7.31 ) or the thermosensitive "Club Wall­ paper", which reveals different motifs as the temperature fluctuates.

Surfaces and coatings

relief embossed textured size print wall murals

C C C C

fine/medium/coarse 1 or 2 layers of paper

backing material: · paper • synthetic material facing material: • expanded vinyl

backing material: · paper • none

backing material: · paper · expanded vinyl · synthetic fleece

facing material: · glass-fibre cloth, fire-resist­ ant, partly bonded with polymer resins

facing material: · cloth, knitted fabric • synthetic fibres

Wall mural "Single Wallpaper" Vinyl wallpaper Textile wallpaper Systematic classification of wallpapers and stretch coverings C 7.35 Life cycle assessment data for plasterwork and coating materials

velour metal foils natural materials

7.31 7.32 7.33 7.34

Natural/synthetic fibres e.g. cotton, linen, silk, polyester

Films, foils, membranes, e.g. PE, PVC, ETFE

Types of cloth, e.g. satin, velour, felt, molton Plasterwork and thermal insulation composite systems Layers • for origin of data see "Life cycle assessments", p . 1 00

PEI primary energy non-renewable [MJ]

PEI primary energy renewable [MJ]

Lime-cement plaster, internal, 2 coats'

110

1 .8

lime-cement plaster MG P 1 1 , scraped, 1 5 mm primer

-

gypsum plaster, internal, 2 coats'

97

gypsum plaster, smooth, 1 5 mm primer

-

insulating plaster

237

GWP ODP ozone global depletion warming [kg CO,eq] [kg R 1 1 eq]

AP acidification [kg SO,eq]

EP eutrophication [kg PO. eq]

POCP summer smog [kg C,H.eq]

7.2

0.071

0.0040

0.0050

0

c::=:::J

CJ

0.065

0.0033

0.0040

0

c::::::J

0

0.22

0.0083

0.Q1 2

0

=

1 .5

5.9

0

=

3.4

C 7.34

16

0

31

0

lime-cement plaster w. expanded perlite aggregate, 1 5 mm thermal insulation composite system

561

lime-cement plaster with glass fleece reinforcement, 3 mm EPS, !.. = 0.035 W/m'K, p = 30 kg/m3, 1 00 mm UF-based adhesive, 3.2 mm

Coatings Layers, layer thicknesses to EN 1 062 • . for origin of data see "Life cycle assessments", p . 1 00

I

24

I

c::=:::J

0.53

0

PEI PEI primary energy primary energy non-renewable renewable

0.0095

I

1 1

GWP global warming

ODP ozone depletion

AP acidification

[MJ]

[MJ]

[kg CO,eq]

[kg R1 1 eq] [kg SO,eq]

0.01

0.22

0

c=:::J

0.024

I 1

EP eutrophication

POCP summer smog

[kg PO.eq]

[kg C,H . eq] [a]

0.00001 0

0.0000 1 0

Durability

Mineral coatings, external lime coating

2.0

hydrated lime coating primer

•

silicate coating, 1 -part

7.3

1 -part silicate dispersion primer

-

0.0001 0

=

1 .4 0

0.26

5

0

0

0.0030

=

0.00028

0.0010

20-25

0.00 1 0

15

0.000 1 0

10

I D

Organic coatings, external alkyd resin coating

4.8

alkyd resin lacquer primer

-

acrylic coating

4.6

acrylic-based high-build glaze coat primer

-

polyurethane coating (screed sealing)

36

2-part polyurethane coating (PUR) primer

1 .4 0

0. 1 4

0. 1 3

0

0

0. 1 5

0

0

1 .5 0

1 .9

0.0020

0.00023

�

0

0.00 1 0

0.000060

0

c:::::J

0

0.021 c::=:=:::J

0.00 1 6

0.0010

1 5 -35

11 C 7.35

201

Part D Case studies in detail

Fig. 0

ETFE cushions on lightweight steel structure, Eden Project, St Austell, UK, 200 1 , Nicholas Grimshaw & Partners

01

Marte. Marte; chapel of rest in Batschuns

(A)

loam

02

Hans-Jorg Ruch; extension to mountain hut in Pontresina

(CH)

timber

03

Perraudin Architectes; wine store in Vauvert

( F)

stone

04

Simon Ungers, with Matthias Altwicker; holiday home in Ithaca

(USA)

l i g htwei g ht concrete

05

MAOA s . p . a . m. ; private house in Lantian Xian

(PRC)

stone

06

Future Systems; private house in Pembrokeshire

(UK)

green roof

07

Lacaton Vassal ; private house in Floirac

(F)

synthetic material

08

Ruben Anderegg ; private house in Meiringen

(CH)

render

09

Snozzi

(NL)

clay brickwork

10

Arte Charpentier & Abbes Tahir; Metro station in Paris

( F)

g lass

11

N I O architecten ; bus terminal i n Hoofddorp

(NL)

synthetic material

12

Edward C u l l inan; workshop for an open-air museum in Sussex

(UK)

timber

13

Kengo Kuma; H i roshige Ando Museum in Batoh

(J )

timber

14

Tezuka; natural history museum in Matsunoyama

(J )

metal

15

NOXlLars Spuybroek; arts centre in Lille

( F)

membrane

16

Hascher Jehle Architektur; art gallery in Stuttgart

(D)

g l ass

17

Allmann Sattler Wappner; service centre in Ludwigshafen

(D)

g lass tiles

18

Riegler Riewe; institute headquarters in Graz

(A)

concrete

19

Tectone ; hotel management school i n Nivill iers

( F)

clay elements

20

Jean-Marc I bos & Myrto Vitart; fire station in Nanterre

(F)

metal

21

Oietz Joppien; service centre i n Frankfurt a m Main

(D)

l i g htwei g ht concrete

22

MVROV; hospital extension in Veldhoven

(NL)

glass

23

Assmann Salomon & Scheidt; 1 1 0 kV substation in Berl in

(D)

stone

24

Sauerbruch H utton; combined police and fire station in Berlin

(D)

g lass

25

Schweger

(D)

membrane

+

Vacch i n i ; apartment block in Maastricht

+

Partner; roof to tennis stad ium in Hamburg

203

Loam

Chapel of rest T

Batschuns, Austria, 2001

Architects: Marte.Marte, Weiler Project team: Robert Zimmermann, Alexandra Fink, Stefan Baur, Davide Paruta Structural engineers: M + G , Feldkirch Loam consultant: Martin Rauch , Schlins

A small chapel of rest was added i n the course of extending the cemetery of the parish church of St John, designed by Clemens Holzmeister in the 1 920s. Access to the new section is via an opening in the cemetery wal l opposite the church. A broad, low wall of tamped loam, which on the sloping side rises to form a wall for cinerary urns, surrounds an open, gravel­ covered area, but does not quite extend as far as the walls of the existing cemetery. And the external concrete access ramp, too, maintains a respectful d istance. At the corner adjacent to the road, the simple, cube-shaped bui l d i n g forming t h e chapel of rest seemingly g rows out of the wall , providing a formal termination to one end of the ensemble, the church forming the other. A wide, asymmetrically positioned door of sanded oak provides access to the completely bare interior. One side wal l is sepa­ rated from the floor by a strip of g lass and appears to float. A slit in the roof allows l i g ht to strike the rear wall at an acute angle. The oak batten i ncorporated vertically in the rear wal l contrasts with the horizontal layered structure of the loam courses to suggest a cross. The plain, geometrical form and the austerity of the ensemble's architectural language contrast with the vibrant, warm surfaces of the tamped loam. The loam used came directly from the excavations. It was mixed with clay brick chip­ pings and clay minerals in an earth-damp con­ sistency and placed in the formwork in 1 20 mm lifts. Mechanical stabil ity was achieved by com­ pacting the individual layers with hand-operat­ ed plant; no chemicals were added to the material. The tops of the walls are protected against rain by slabs bonded with a trass-lime binder. Erosion of the external surfaces was allowed for by oversizing the loam components to a certain extent. Despite loam bei n g a labour-intensive building material, the dedica­ tion of a number of people in the local commu­ nity ensured that it was chosen instead of con­ crete for this project. QJ

I 'architecture d 'aujourd 'hui 346, 2003 Detail 06/2003

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Extension to mountain hut

Pontresina, Switzerland, 2003

Architect: Hans-Jorg Ruch, St Moritz Project team: Sacha Michael Fahrn i , Stefan Lauener, Alan Abrecht, Velia Jochum Structural engineer: Beat Birchler, Silvaplana

The Tschierva H ut is just one of about 1 50 mountain huts belonging to the Swiss Alpine Club and is situated between imposing peaks at an altitude of 2583 m. The extension proved to be a difficult undertaking because - besides the client - various authorities, such as the Swiss Nature and Homeland Protection Com­ mission , also had to be involved. However, the architect was able to convince all sides that a deliberate contrast between old and new was a good solution. The concept left the existing hut more or less undisturbed and added an extension which, with its distinct cube-like shape and timber facade, sets itself apart from the stonework of the existing build ing. Almost as if it wishes to capture the magnificent views, it cantilevers out inquisitively over the front retaining wall and forms one boundary to the sheltered rooftop terrace. The new staircase enabled compliance with the fire brigade stipulations and also mini­ mised the changes to the existing construction. Although the Tschierva Hut still only provides accommodation for 1 00 guests, the standard of comfort has been considerably i mproved: the sleeping berths are wider, the kitchen is more spacious, and the dining room in the extension provides additional seating . It was not only the desired appearance that dictated the use of timber for the extension. The remote mountainside location required maximum off-site prefabrication and m inimum on-site erection time in order to cut down the high cost of transport by helicopter and reduce the power and water supplies on the building site. The extension employs a double-leaf con­ struction. The outer leaf consists of steel stan­ chions with planks of larch f itted between the flanges; this form of construction protects the building against avalanches. Prefabricated tim­ ber wall elements in panel construction and timber floors of edge-fixed boards form the internal load bearing structure. Construction elements left partly exposed internally and fur­ niture of solid wood designed especially for this project mean that wood is the dominant materi­ al on the inside as wel l . Q;J

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Stone

Wine store

Vauvert, France, 1 999

Architects: Perraudi n Architectes, Lyon Gilles Perraud in Structural engineers: Franc;:ois Marre, Lyon

The governing parameters for the storage of wine are constant, moderate temperatures with minimal fluctuations. The architects managed to achieve this goal by using natural building materials and exclusively natural forms of i nteri­ or c l imate control . A succession of storage and office rooms grouped around an internal courtyard forms a compact, square structure. The external sur­ face area is small in comparison to the enclosed volume and this reduces the i nflu­ ence of the external temperature on the internal climate. The sol i d external walls, 520 mm thick, provide the necessary storage mass required to achieve the high thermal inertia of this struc­ ture. During the day they absorb incident heat and discharge this at n ight, assisted by the brisk sea breeze. The rooftop p lantin g is also designed to act as a c l imate buffer. The deep plant-bearing layer holds rainwater which later evaporates and creates a cooling effect. The shelly limestone used - with moderate hardness and a density of 1 800 kg/m3 - was obtained from a quarry just 30 km away. Saw­ i n g directly out of the solid rockface resulted in large blocks measuri n g 1 050 x 1 050 x 2 1 002600 mm, and for the wine store project these huge blocks were merely d ivided in two. The 2.5 t blocks were transported to the site ( 1 0 per truck) and lifted into place with the help of a mobile crane. No mortar was used to connect the blocks (dry wall i n g ) , merely a layer of mor­ tar approx. 50 mm thick to create a level bed. This simple form of construction resu lted in three workers requiring hardly one month to position a l l the 300 or so blocks for the walls. The high cost of the stone was offset by the minimal processi n g of the materials and the short time on site. The durabil ity of such a form of stone construction is readily visible in a structure that was built 2 1 00 years ago with stone from the same region, namely the Pont du Gard in NTmes. Q;J

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Holiday home

Ithaca (New York), USA, 2000

Architect: Simon Ungers, Cologne, with Matthias Altwicker, New York Contractor: Bruno Schickel Construction, New York Structural engineer: Peter Novelli, Ithaca

This holiday home is situated in New England, about 300 km north-west of New York. It is built entirely of concrete blocks with pumi ce aggre­ gate - a cheap, simple material that is used in the USA primari ly for building basements. The house, simple, but in no way conventional, measures 6 x 7 x 7 m and was built by the architect for his own use. The openings of dif­ ferent sizes and proportions were kept to a minimum and incorporated into the naked grey cube with considerable forethought. The dark grey-painted steel windows and doors appear l ike areas of colour in a minimalist painting; not even the arrangement of the rainwater outlet was left to chance. All junctions and details are minimised so that even sheet metal window sills are unnecessary. Simplicity governs the layout of the interior, with about 90 m2 of floor space. The ground floor has a garage, studio and small office. Timber stairs lead to the upper floor, with living, dining and sleeping areas i n an open-plan arrange­ ment, p lus bathroom and kitchen area. Low­ level bookshelves serve as a room d ivider. A 3.30 x 2.40 m window opposite the kitchen provides a generous view of the natural sur­ roundings. Oak wood-block flooring and built-i n furniture of birch plywood create a n inviting atmosphere. On the east side dark-grey steel stairs lead to a 40 m2 rooftop terrace, which is hidden behind a raised parapet. From here it is possible to watch foxes and deer in their natural habitat. CD

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Private house

Lantian Xian, China, 2003

Architects: MADA s . p . a . m . , Shanghai Project team: Qingyun Ma, Weihan Chan, Peter Knutson, Yinghui Wan g , Satoko Saeki, James Macg i l

The architect built this house for h i s father in the vicinity of Lantian Xian, about 1 500 km north-east of Beijing. The result is an introvert­ ed, cube-like building that combines both tradi­ tional and modern methods. The structural framework is provided by 400 x 400 mm reinforced concrete columns and beams positioned on a 4.80 m or 1.40 m grid. The wal l panels between the load bearin g mem­ bers are faced with smal l stones - a material that in this region is normally used for free­ standing walls around fields and plots of land. The villagers helped the client to collect every stone from the bed of the nearby river and sort them according to colour, size and form . Every wall panel thus has its own texture and colour nuances, which also vary depending on the weather and the light. The stones are cast in concrete, which is fixed to the load bearing structure by means of steel anchors. The interior - configured by the exposed con­ crete columns - has a simple, but not unfriend­ ly look. Woven, untreated bamboo panels, which in this region are normally used as form­ work for concrete, cover the floors, ceilings and walls. The rooms on the south side - an open­ plan l iving and dining area, with study and bedroom above - have full-height g lazing opening onto an enclosed courtyard . The deli­ cate colour and texture nuances of the stone walls, the grey fair-face concrete and a cooling pool create an atmosphere of meditation. Kitch­ en, bathroom and a room for guests are situat­ ed on the north side. A 4 m high wal l encloses the house, courtyard and narrow pool. Just a few storey-high windows with hinged and slid­ ing shutters of bamboo provide views across the undulating landscape. C);J

212

Architectural Record 1 2/2003 A+U 1 212003 The Phaidon Atlas of Contemporary World Architecture, London, 2003

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Private house

Pembrokeshire, UK, 1 994

Architects: Future Systems, London Structural engineers: Techniker, London

Situated just 25 m back from the edge of the cliffs, this house provides a view over St Bride's Bay on the Welsh coast. The present building replaced a m i litary observation post on the same site that had already been converted into a cottage. The house tries to blend into the landscape as far as possible; the roof and the backfilled side walls merge with the natural sur­ roundings to produce an almost organic form. The entrance in the rear wall is concealed behind a small knol l ; only on the seaward side does the building become really apparent - its elliptical glazing appearing l i ke an eye watch­ ing over the landscape. The glazing ensures not only a good view of the sea from all rooms, but also good lighting conditions throughout the house. The two bedrooms at the ends of the house are separated from the central l iving area by sepa­ rate bathroom units, one of which also incorpo­ rates the kitchen area. All the furniture was deSigned by the architects; the seating arranged around the open fireplace forms the focal point of the house. Retaining walls of concrete blocks were built on the in situ concrete raft foundation. The entire roof construction is supported on a steel ring beam, making further internal columns unnec­ essary. The roof consists of painted laminated veneer lumber boards attached to a steel framework, the shape of which is reminiscent of an upturned aircraft wing . The bathroom units, made from painted plywood , were prefabricat­ ed - including all the connections. The house is heated by electric coils integrated into the floor. The rooftop planting and the side walls in con­ tact with the soil ensure a pleasant interior cli­ mate throughout the year. The front facade with its fine posts between the panes of double g lazing includes genuine portholes that can be opened for ventilation. CD

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I'architecture d 'aujourd 'hui 324, 1 999 A+U 346, 1 999 Field , Marcus: Future Systems, London, 1 999

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Private house

Floirac, France, 1 993

Architects: Anne Lacaton & Jean Philippe Vassal , Paris Assistant: Sylvain Menaud Structural engineers: C.E.S.MA, Bordeaux

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Meiringen, Switzerland, 2005

Architect: Ruben Anderegg, Meiringen Structural engineers: Stampfli & Zbinden, I nterlaken

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The village of Meiringen lies in the Hasli Valley, about 30 km to the east of I nterlaken in the Ber­ nese Oberland. Like in many Alpine regions, log construction is regarded as the traditional form of construction. But here on the edge of the village, a distinctive, almost cube-shaped detached house with a prism-like roof stands out clearly from its neighbours due to its materi­ als and its minimal architectural language. A carport, in fair-face concrete like the garden walls, adjoins one side of the house with its grey render finish, merging with the set-back entrance, emphasised by being raised above the road level. I nside, the open-plan accommo­ dation is the key theme. The kitche n , dining and living areas merge, and the living room extends over the full two storeys. Large win­ dows on both levels plus a slit-like rooflight cre­ ate a bright atmosphere at any time of day. The small office in the basement is wel l lit from the window opening out onto the gravel-covered, subterranean courtyard . This can also be reached via a stair between carport and gar­ den wall, which means that business visitors do not have to pass through the house. The unu­ sual surface finish to this house makes it con­ spicuous, but also helps it to blend in well with the rough mountain landscape. The single-leaf walls of aerated concrete blocks were covered with a render undercoat which was a llowed to dry overnight. On the next day a second coat of the same material was appl ied and scraped horizontally with a float before it had fully hard­ ened. This technique results in a vigorous tex­ ture, which reminds the observer of elephant skin and has led to this house being christened as such.

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Apartment block

Maastricht, Netherlands, 2003

Architects: Snozzi + Vacchini, Locarno Project team: Mario Ferrari, Wilfried Schmidt, Anne Javet, Isabelle Valazza

This apartment block is part of the new Ceramique development built on the site of a former ceramics factory. The master plan, heavily dominated by traditional urban planning concepts, used the Greek term stoa (= covered colonnade) to describe the building of covered urban functions. The name has remained, but the permeability ori ginally planned has been severely cut back. The seven-storey block nearly 300 m long runs paral lel to the park along the banks of the River Maas and at this exposed site acts as both a focal point and an advertisement for the new development. Two-storey passageways pene­ trate the building at regular intervals and pre­ vent the area behind from being cut off com­ pletely from the riverbank. The passageways are accompanied by taller sections and returns in a facade punctuated by alternating groups of windows and loggias in identical formats. Returns and projections in the facade also vary the floor space on each storey, and this led to many different types of apartment. The load­ bearing reinforced concrete frame is clad in clay brickwork, which allowed the architects to create a reference to traditional Dutch buildi n g . The brickwork g ives t h e building a finely struc­ tured surface, contrasting agreeably with the fair-face concrete plinth and garden walls. CIJ

Das BauzentrumlBaukultur 0 1 /2003

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221

G lass

Metro station

Paris, France, 2003

Architects: Arte Charpentier & Abbes Tahir, Paris Project team: Pierre Clement, Minh Tran, Gregoire Mussat, Alain Jacquet, Frederique Crozet, Philippe Normier, Philippe Almon Structural engineers: RFR, Paris

Set amid venerable houses from the late 1 9th century on the Place de Rome in Paris, a new, dynamic, bulb-shaped construction of g lass and stain less steel marks the main entrance to the St Lazare Metro station. Below the g lass dome, stairs, lifts and escalators convey travel­ lers to and from the brightly l it underground station below. Two enormous electrically driven stainless steel louvre doors permit access dur­ ing the day but are closed at night. The com­ plex geometry of this 1 5 m wide and max. 4 m high g lass protrusion was generated by super­ imposing a sphere on a toroid. The junction with the ground is at an angle because of the gentle slope of the ground at this point. Eleven longitudinal and nine transverse arches of V-shaped stainless steel sections g ive the structure its double curvature. They are welded to an elliptical stainless steel ring that is anchored to a concrete slab. Specially fabricat­ ed components, also of stainless steel, join the arches at their intersections. The slender sec­ tions were made possible by the grid of stain­ less steel cables in the outer part of the dome, which accommodate some of the total load and also brace the construction against wind forc­ es. All the structural members were prefabricat­ ed with great precision by a company special­ ised in aircraft components. They were trans­ ported to the site in seven pieces and then assembled. The covering of glass comprises 1 08 d ifferent panes in double curvature made from extra­ clear laminated safety g lass. Each pane of g lass is bonded on all sides to a flat stai n less steel flame frame which is in turn connected to the structural members underneath by special individual articulated fittings. S i licone joints (25 mm wide) seal the butt joints between the panes of g lass and also separate the panes so that in the case of damage only one pane has to be replaced. CIJ

222

I'architecture d 'aujourd 'hui 352 , 2004 Techniques + architecture 472, 2004

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223

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Bus terminal

Hoofddorp, Netherlands, 2003

Architects: N I O architecten, Rotterdam Project team: Henk Bultstra, Mirjam Galje, Hans Larsen, Maurice Nio, Jaakko van 't Spijker Structural engineers: Ingenieursbureau Zonneveld, Rotterdam Engiplast, Middelburg

Elevated highways, a railway embankment, ter­ race houses, a hospital - no man's land on the outskirts of the Dutch town of Hoofddorp, a suburb of Amsterdam. But unbelievably, a bus terminal belonging to the municipal public transport company has managed to create some kind of identity here: a h i g h ly orig inal, shimmering off-white "blob" lies here as if stranded on an island, sometimes reminding the observer of a serpentine sea creature, sometimes a pebble washed clean of sand and seawater. The long curving openings are ele­ gantly formed in the material - devised by the architects with the help of viewpoint references and circulation lines. Benches, lighting units, rubbish bins and a display case are incorporat­ ed into cave-like recesses in the structure. Space was also found in this sculpture to include a small room for the hard-working bus drivers to relax during their brief breaks. The construction appears to be solid and heavy, but in actual fact it is very light because it consists entirely of polystyrene foam. It con­ sists of five elements that were prefabricated (CNC milling) and finished (transparent polyes­ ter resin coating) in the factory. On site the indi­ vidual elements were g l ued together and sprayed with a further 5-7 mm thick coating of polyester resin intended to protect the building against the weather and vandal ism (kicks, cig­ arette burns, etc . ) . Concrete foundations 2 m deep anchor the l i ghtweight structure to the subsoil . Despite - o r perhaps due to - the very low budget of one million euros, which would have been wholly inadequate for a bus terminal using conventional methods of construction, the architects have created not only an unusual structure, but at the same time with d i mensions of 50 x 1 0 x 5 m the world 's largest polystyrene foam object! Q;J

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Timber

Workshop for an open-air museum

Sussex, UK, 2002

Architect: Edward Cullinan, London Project team: Ted Cullinan, Steve Johnson, Robi n Nicholson, John Romer Structural engineers: Buro Happold, Bath

The workshop complements an open-air muse­ um for traditional timber b u i l d i ngs in southern England. The 48 m lon g , max. 16 m wide and max. 1 2 m high building is used by the muse­ um's carpenters for the faithful re-assembly of exhibits removed from other sites. This elongated, three-crested wave-l i ke timber lattice she l l - the first of its kind in the UK is founded on a reinforced concrete basement storey. Architect, engineers and carpenters developed the construction principle in close collaboration. Deviating from previous approaches in which the lattice shell was pre­ assembled as a mat on the ground and then raised into position, the design team in this case exploited the force of gravity: the lattice mat was assembled atop a 7 m scaffold and took on its final form gradually as the scaffold was carefully dismantled. The structure com­ prises four layers of criss-crossing oak battens which are particularly flexible because they are made from freshly fel led, undried timber. The patented node joints are positioned on a 1 m grid, which is reduced to 500 mm in more heavily loaded areas. Simple steel nodes con­ sisting of three plates and four bolts connect the individual battens. The middle plate has a steel pin on each side to fix the two central tim­ ber battens and determine the geometry of the lattice. The two outer steel plates g u i de the two outer battens during assembly and afterwards hold them in place. As soon as the construction has achieved its final form, the nodes are stabi­ lised by tightening the bolts. Further transverse and longitudinal battens attached on the out­ side help to brace the structure and also serve as the supporting framework for the facade cladding of untreated cedar battens. -

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Example 1 3

Hiroshige Ando Museum

Batoh, Japan, 2000

Architects: Kengo Kuma, Tokyo Ando Architecture Design Office, Tokyo Project team: S. Oshio, S. Yasukouch i , T. Yada, H. Nakamura, Y. Sakano, T. Goto, Ryusuke Fujieda design team , Ando Architects - M . Nakatsu, T . Shibata Structural engineers: Aoki Structural Engineers, Tokyo

A museum dedicated to the artist H i roshige Ando was built in his birthplace, about an hour's drive north of Tokyo. H i roshige Ando is one of the most famous exponents of ukiyo-e, a Japanese art form that depicts natural phe­ nomena such as l i g ht, wind, rain and mist in an abstract form. The method of portraying such variable and complex phenomena was embod­ ied in the concept for the museum. The arche­ typal form of a house was erected in this heavi­ ly forested area using closely, regularly spaced timber battens just 30 mm thick, which enclose this long building like a veil . This subtle enve­ lope holds the structure together; the play of transparency, light and materials leads to asso­ ciations with clouds - an accumulation of the finest water droplets which purely through their compacted form create a visible, but constantly changing phenomenon . The trees of the sur­ roundings are reflected in the facade and allow the observer to surmise - rather than actually see - the frame-less glazing beneath the cedar battens. The concept of an enclosed vol ume within this permeable envelope cannot be grasped directly because the boundaries vary depending on the nature of the incoming l i g ht. Underneath the construction of timber battens supported on exposed steel sections there are panes of glass, insulated concrete walls, meta l roofs, glass rooflights or open passageways. Tracking the altitude of the sun and the vagar­ ies of the weather, the degree of transparency changes constantly along with the colours; the cedar envelope becomes a permeable filter. Inside the building as wel l , despite the numer­ ous rooms with fixed boundaries, the play of glass surfaces, sol i d walls and trad itional Japa­ nese room dividers of paper becomes irritating in a fasc inating way. The restrained colours of the untreated materials create a contemplative, almost melancholy, atmosphere. Only when visitors arrive at the very heart of the building do they find themselves in artificially illuminated rooms, face to face with the l i g ht-sensitive exhibits from the artist's Edo period . CD

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Natural history museum

Matsunoyama, Japan, 2002

Architects: Takaharu & Yui Tezuka, Tokyo Masahiro I keda, Tokyo Project team: Masafumi Harada, Ryuya Maio, Hirofu m i Ono, Makoto Takei, Hiroshi Tomikawa

About 200 km north of Tokyo, in the region around the Mikuni Mountains, it often snows so hard that depths of more than 5 m are not unu­ sual, which is why this region is also known as "Snowland". During such extreme weather con­ ditions all that remains to be seen of the muse­ um is its 34 m high tower leading to the viewin g platform; the 1 60 m lon g , snake-like m a i n build­ ing with its exhibition rooms, hall for events, cafe and research faci lities lies hidden like a submarine beneath the mass of snow. Visitors pass high walls of snow as they approach the entrance. Once inside, a meandering path takes them through the museum, its shape reminding them of the tracks throug h the sur­ rounding forest. At each of the bends in the building, room-high panorama windows g ive visitors the chance to enjoy the whole focus of the exhibition - the surrounding nature - directly. In order to withstand snow loads of up to 1 .5 Vm2, the building envelope consists of 6 mm thick, weathering steel plates with their reddish-brown (i.e. pre-rusted) surface. The plates were welded to a supporting structure of steel columns and beams in situ; the work was inspected by a company special ised in boat­ building. Like a thermos flask, the building envelope consists of two independent skins. With temperatures as low as -20°C in winter and as high as +45°C in summer, the outer steel skin expands by up to 200 mm in the hori­ zontal direction. This change in length is accommodated by a special sliding detail at the jOint between steel column and foundation. The load bearing structure is fixed at three points only so that the building always returns to its original position. The plasterboard walls attached to a separate framework remain unaffected by the movements of the external skin. Air - warm in winter, cold in summer ­ circulates in the interven i n g cavity and this helps to control the temperature of the i nterior. ClJ

232

Architectural Review 08/2004 Detail 04/2005 domus 875, 2004

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Arts Centre

Lille, France, 2004 Architects: NOXlLars Spuybroek, Rotterdam Project team: Florent Rougemont, Lo'lc Gestin, Chris Seung-Woo Yoo, Kris Mun, Ouafa Messaoud i , Estelle Depaepe, Bernhard Frodl , Josef G las Structural engineers: Maning, Vil leneuve d 'Ascq

The "European City of Culture" award in 2004 gave Lille the chance to convert an old spin­ ning mill into a modern arts centre. The group of buildings in Wazemmes, a l ively part of the city, is now home to various facilities for events and exhibitions, as well as studios, artists' apartments, a Turkish bath and a brewery. Wherever possible, the old buildings were retained and refurbished. Merely one-third of the former production building was demolished and a new building erected in its place to fit in with the form and scale of its surroundings. The new construction provides a 750-seat multi­ purpose hall for concerts, plays and fashion shows. The architectural language of the curv­ ing paths and areas of greenery of the new forecourt in front of the building continues into the sculpted form of the fully glazed entrance foyer, where curvin g , colourful shapes in gyp­ sum plaster entice the visitor to enter this other­ wise i ntroverted building. From further away, it is left to the facade to show that something special is happening here. A curving envelope of stainless steel fabric covers the two long sides of the concrete structure with its g loss black paint finish. Oval holes are cut in the curving form, which extends above the roofline. The curved facade posts of galvanised steel every one unique - on a 1 .50 m grid are visible from certain angles. Each bay is clad with a strip of stainless steel fabric. The character of the facade varies depending on the weather conditions and the viewer's perspective: some­ times shining in the sunlight, sometimes opaque and closed, then again transparent and permeable; and at night illuminated by floodlights behind the fabric. co

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Art Gallery

Stuttgart, Germany, 2004

Architects: Hascher Jehle Architektur, Berlin Project managers: Thomas Kramps, Beate Leidner, Arndt Sanger, Eberhard Veit Structural engineer: Werner Sobek, Stuttgart, with Fichtner Bauconsult, Stuttgart

For a long time the plot in the centre of Stutt­ gart's pedestrian precinct was regarded as a planning quandary. The gap in the urban fabric of K6nigstrasse had been an eyesore since the war. The town square that evolved on this site was merely the concrete roof slab to a road tunnel. Several temporary buildings and four urban planning or architectural design compe­ titions followed, which in 1 999 finely produced the scheme for the city's collection of art works. The lion's share of the 4900 m2 of exhibition space in the new structure is provided by the road tunnel - now defunct. And above groun d , a glass c u b e measuring 29 x 29 x 26 m has now closed the gap in the K6nigstrasse street­ scape. The glass cube contains a stone-clad core with further exhi bition rooms plus, on the topmost floor, a restaurant with a view of the square that fronts the palace and, in the dis­ tance, the surrounding hills. The glass roof is supported on adjustable steel posts, which are in turn carried on a rigid grid of welded steel beams and 4 m long glass webs (acting as secondary beams) . The beam grid is supported on 1 2 steel columns. Milled T­ section steel members suspended from the roof beams carry the facade, helped by 60 mm thick glass fins to resist the wind loads. The fins can slide vertically in their fixings at the inter­ mediate floors in order to accommodate changes in length due to temperature fluctua­ tions. The extra-clear glass employed ensures no col­ our distortions either looking into or out of the building. To give the appearance of a com­ pletely glass surface, a rebate has been ground into each longitudinal edge of the 4. 1 0 x 2.50 m g lass elements so that the outer glaz­ ing cap lies flush with the g lass. Despite its complete envelope of g lass, the interior of the building receives only about 25% of the inci­ dent solar radiation. This is due to the solar­ control and heat-absorbing coatings plus the argon-fil l ed cavity between the inner and outer panes, also the horizontal stripes printed on the glass, the number of which gradually reduces towards the top of the building. CD

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239

G lass tiles

Service centre

Ludwigshafen, Germany, 2003

Architects: Allmann Sattler Wappner, Munich Project team: Marion Kalmer Melanie Becker, Christof Killius, Thomas Meusburger, Ulf Rbssler Structural engineer: Werner Sobek, Stuttgart

The Brunk Estate, a housing development for workers dating from the 1 930s, is located directly opposite the BASF works, and separat­ ed from it by just one very busy main road. It was along this axis that the new service centre was built to accommodate the offices of the company's own housing and health i n surance services. From the road, the observer first sees a 1 60 m long block that forms a d istinct con­ trast to the surrounding small-format develop­ ments. This block contains ancil lary and meet­ ing rooms and acts as a noise barrier for both the adjoining park and the more sensitive areas of the centre. At the same time, it connects five three-storey office wings with open courtyards and single-storey entrance foyers in between . Large areas of glazing break up the otherwise monolithic facade and provide views into the building and also g l i mpses of the park on the other side. The interplay between solidity and transparency is enhanced by the indistinct reflections in the facade sections clad with glass tiles. The enamel on the back of each tile leads to an iridescent play of colour on the building envelope, reminding the observer of mother of pearl and producing a blurred reflec­ tion of the surroundings which chang es according to the light. The 48 x 48 mm ti les were supplied fixed to a mesh backing in 300 x 300 mm units and then g lued to backing pan­ els of cellular glass granules i n front of a venti­ lated cavity. The thermal insulation require­ ments precluded the fixing of the tiles directly to the reinforced concrete walls; in addition, glass tiles and concrete exhibit different ther­ mal expansion behaviour. The 2 mm expansion joints every 1 .5 m were coloured and given a sanded finish to achieve a perfect match with the rest of the surface. QJ

240

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I nstitute headquarters

Graz Technical University, Austria, 2000

Architects: Rieg ler Riewe, Graz Project team: Manuela Muller, Fritz Mosshammer, U lrich Huhs, Andreas Allerberger Structural engineer: Stefan Rock, Graz

The headquarters for the IT and Electrical Engi­ neering Institute at the University refrained from making any kind of reference to its nondescript neighbours consisting of various accommoda­ tion blocks and university faci l ities. The ensem­ ble forms an independent, withdrawn commu­ nity of closely spaced, elongated concrete blocks - i nterconnected by bridges, corridors and internal "pathways" on all levels - enclos­ ing courtyards and open spaces of various sizes. Each of the three-storey buildings is divided into two parts lengthwise but still linked i ntermittently across a 4 m wide "cavity". The facade construction is separated from the load­ bearing structure so that openings can be posi­ tioned exactly as requ i red. The internally insu­ lated reinforced concrete panels are suspend­ ed from the structure like a curtain wal l . The careful use of materials a n d textures ena­ bled the architects to achieve a certain harmo­ ny. For example, second-hand and artificially roughened formwork panels were used for the i n situ concrete in order to g ive the surface an irregular, raw look. Furthermore, 3% black pig­ ment was added to the grey cement, but une­ venly so that various shades of grey were obtained. Concrete is also the material used outside for the paving and hardstandings around the buildings, thus blurring the boundary between internal and external. Heavily trafficked areas inside the buildings are also dominated by unrefined materials: fair-face concrete walls, terrazzo floorin g , galvanised steel doors. In order to make the rooms appear bri g hter, the walls between offices and corridors were not coloured in any way. Besides their load bearing function, they have to fulfil high standards of sound insulation and fire resistance; and owing to their storage mass they also offer thermal benefits. QJ

242

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Example 1 9

Hotel management school

Nivill iers, France, 2000

Architects: Sabri Bendimerad & Pascal Chombart de Lauwe, tectone, Paris Assistant: Yann Rault Structural engineers: BECIP, Beauvais

The small park on the edge of the little village of Nivilliers, about 10 km from Beauvais, includes a palace dating from the 1 9th century and a hunting lodge from the 1 8th. It is in this setting that a hotel management school with associated accommodation has been erected. The two accommodation blocks on the bound­ aries of the plot each provide space for 1 2 stu­ dents. The school itself adjoins the existing pal­ ace at a right-angle and thus defines a court­ yard with a majestic 200-year-old cedar tree at its centre. I n this L-shaped layout the access corridor alongside the courtyard is fully g lazed and therefore clearly d istin guishes itself from the existing building. But contrasting with this, the other facades and the accommodation buildings make use of large clay elements that blend in well with the clay brickwork of the his­ toric building stock. These monolithic hollow clay elements require no further surface finish­ es and therefore - compared with conventional clay brickwork - result in a less expensive con­ struction completed in less time. The standard elements with expanded polyurethane foam insulation and special connectors for corners, lintels and spandrel panels form a modu lar sys­ tem that is usually employed for large agricul­ tural and industrial buildings. The standard heights range from 2500 to 2800 mm, the width is always a multiple of the basic 1 50 mm mod­ ule - in this project 300 and 600 mm. This results in a flexible facade grid in which the openings can be positioned as require d . The clay panels are anchored to the foundation and floor slabs by means of reinforcing bars in the corners, which can either be factory-integrated or grouted in on site. The outermost void of the clay element acts as a ventilation cavity for the exposed surface and thus helps to ensure that any condensation in the insulation can escape. The clay elements therefore cantilever out from the floor slabs in order to guarantee unhin­ dered air circulation. co

I 'architecture d 'aujourd'hui 329, 2000 Detail 04/2001

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Nanterre, France, 2004

Architects: Jean-Marc I bos & Myrto Vitart, Paris Project team: Marie-Alix Beaugier, Stephane Bara, Agnes Plumet Structural eng ineers: Khephren I ngenierie, Arcueil

The fire station in the Paris suburb of Nanterre embodies one principle above all others: effi­ ciency. The design brief stipulated that the fire crews must be able to reach the inner court­ yard from any part of the station within one minute. This stipulation determined the layout. The cen­ tral yard measuring 55 x 35 m is bounded on three sides by two-storey blocks containing control centre, garages, workshops and sports hall on the ground floor, p l us bedrooms and offices above. Rising above the two-storey con­ struction at the end of the yard is a 67 m lon g , five-storey block with apartments for t h e fami­ lies of the fire-fighters. Elevated on a black­ painted, set-back intermediate plinth , the block appears to float, despite its solid appearance. On the yard side, two wide bays with balconies extending over the full height of the block pro­ vide relief. The variously sized apartments to suit the needs of different fam i lies are posi­ tioned around the three main access towers with lifts and stairs - but also the indispensable poles for the fire crews. The materials of the facades also had to satisfy functional criteria: robust, durable and easy to maintain. The architects therefore chose metal: highly polished, silvery reflective trapezoidal profile sheeting of stainless steel is used on the fire station itself. Its thickness of 2 mm enables it to withstand virtually any mechanical impact. The various windows appear to be positioned at random, but in fact match internal require­ ments exactly. The apartment block, on the other hand, is clad in copper-coloured, corru­ gated, anodised aluminium sheeting with a matt finish. The room-high aluminium window frames flush with the facade are finished in the same copper colour. Most of the panes of glass have a solar-control reflective coating in a brownish gold colour. PVC blinds i n yellow, red or orange - the colour of fire - provided between some of the window panes help to create a warm light in the living accommoda­ tion. r::o

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Service centre

Frankfurt am Main, Germany, 2004

Arc h itects: Dietz Joppien, Frankfurt am MainlPotsdam Project team: Matthias Schbnau (project manager) Torsten Herzog, Thomas Kahmann, Christian Haber, Joachim Stephan, Nicole Weinbrecht, Sandra Grosse, Sahra Wolff Structural engineers: TPK, Frankfurt am Main

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The "unerforschte Frankfurter Osten" - the "unexplored east of Frankfurt" - is a business park with a motley collection of structures and it was this title, abbreviated to " UFO", that gave this multi-tenant services and events centre its name. I ndeed, the building is somewhat unusu­ al: an introverted five-storey monolith over a tri­ angular plan. A single window format on a strict grid perforates its road-side fair-face concrete facade. Only the corner adjacent to the road junction opens out in the form of an 8 m high entrance with a contrasting red ramp enticing visitors to explore the interior. The entrance zone is 42 m wide and the storeys above canti­ lever around the corner in a Vierendeel g i rder­ like arrangement. An entrance within the ramp leads to the events area on the ground floor, a further entrance provides access to the upper storeys with their offices, which are arranged around the triangular inner courtyard. Covered walkways, open on the courtyard side, connect commercial units of various sizes that are rent­ ed with service cores only. Partitioning and fit­ ting-out must be determined by the tenants themselves. Most of the load bearing internal walls and the insides of the road-side wal l s have been left in fair-face concrete. The external walls emphasise the monolithic appearance of the build i n g . They consist of 500 mm thick lightwei g ht concrete which requires no additional thermal insulation. The architects wanted no expansion joints and as few formwork tie holes as possible, and speci­ fied all construction joints and recesses. Every concrete pour was cast d i rectly on the previous pour to conceal the i ntermediate joint and cre­ ate an uninterrupted surface. In addition , slight­ ly absorbent formwork panels made from coarse particleboard plus elaborate curing measures were necessary to create the lightly textured , crack-free surface finish. To ensure consistent curing of the concrete, it was kept moist for three weeks by a sprayed film that slowly disintegrated under the action of u ltravi­ olet light. QJ

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Glass

Hospital extension

Veldhoven, Netherlands, 2002

Architects: MVRDV, Rotterdam Winy Maas, Jacob van Rijs, Nathalie de Vries Project team: Anet Schurink, Duzan Doepel, Jeroen Zuidgeest, Ebami Tom , U l rika Connheim, Pieter Kleinmann G lass contractor: Gakon B.v., Wateringen

The "greenhouse" is an extension to a hospital in the Dutch town of Veldhoven. It provides areas in which the patients can temporarily for­ get the hospital itself with its long corridors and smell of disinfectant. Four boxes, of different sizes and containing an aud itorium, meeting rooms, offices and an information centre, are positioned seemingly at random within the glass enclosure. The spaces between the boxes - with trees providing shade - are intended to be used as communal areas. At the eastern end of the building the space is used by a restaurant. Stairs lead to the roofs of the boxes, which provide further communal areas and allows patients and visi­ tors to enjoy a view over the leafy crowns of the 6 m high olive trees imported from Florida. To keep costs down, the architects chose a standard greenhouse construction system for the building envelope, with a load bearin g structure of steel columns o n a 4.00 x 3.50 m grid and welded steel lattice beams. Panes of double glazing form the walls, whereas the roof is covered with transparent polycarbonate sheets. Opening lights at the ridge and in the top half of the walls ensure the necessary venti­ lation. Underfloor heating inside the boxes guarantees comfortable conditions throughout the year, whereas the " g reenhouse" serves as a zone of intermediate temperature. Fabric blinds mounted below the polycarbonate roof protect against overheating in summer. The boxes of calcium silicate masonry, l ike the floor, have a special surface finish: primer, undercoat and a thick spray coating of white polyurethane resin which, once dry, forms a network of wide cracks to reveal the l ight grey undercoat underneath. A transparent sealing coat protects this finish. The idea behind this so-called crazing is to simulate the parched, cracked earth of hot countries. c:o

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Stone

1 1 0 kV substation

Berlin, Germany, 1 999

Architects: Assmann Salomon & Scheidt, Berlin Project team: Frank Kasprusch, Burkhart von Franque Structural engineers: Hildebrand & Sieber, Berlin Client: BEWAG, Berlin

Here in Friedrichshain , a district of Berl i n , the scale of this substation belonging to the munic­ ipal electricity supply company is somewhat irritating . Everything is larger than the neigh­ bouring buildings, which primarily date from the late 1 9th century. With its length of more than 60 m, the four-storey substation occupies the space of virtually a complete block of hous­ es; the ground floor is 6 m high, the doors and windows 5.0 m and 2.5 m respectively. And the austere appearance is further reinforced by the large-format grey basalt cladding panels that cover the entire facade. Nevertheless, the building is not unappea l i n g . The seven storey­ high, notch-like openings at ground floor level enable passers-by to see what is normally hid­ den from their view: the enormous switchgear and transformers. None of the openings are positioned according to a regular pattern and this lends the building plasticity. Another open­ ing extending virtually the full height of the building denotes the staircase, whereas the set-back longitudinal windows cut throug h the facade at an angle to create deep shadows. The facade cladding continues into the splayed reveals and the shorter side of each, on plan, triangular opening is completed with g lazin g . Lighting behind t h e windows a t night provides an illuminated setting for this stone sculpture. And finally, owing to the varying shades of grey and varying textures of the l ightly ground basalt from the Eifel region of Germany, the appear­ ance is not monotonous, despite the buildi n g 's size. The cladding panels are attached in regu­ lar 500 mm courses but with a random bond using the three d ifferent panel lengths of 1 1 00, 1 300 and 1 500 mm. QJ

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257

G lass

Combined police and fire station

Berlin, Germany, 2004

Architects: Sauerbruch Hutton, Berlin Matthias Sauerbruch, Louisa Hutton, Jens Ludloff, Juan Lucas Young Project team: Sven Holzgreve, Jurgen Bartenschlag (project management) ; Lara Eichwede, Daniela McCarthy, Florian Vblker (site management); Marcus Hsu, Konrad Opitz (competition) Structural engineers: Arup, Berlin The new combined police and fire station for this district of Berlin is located on an inner-city brown-field site on the banks of the River Spree. The new building supplements an exist­ ing structure from the 1 9th century, the only remaining part of the former customs facil ities of the Moabit rail freight depot. Built onto the fire wall of the old building, the new block uses the existing wing for access. The ground floor has garages for police vehicles and fire eng ines. The two floors of offices above are clad in colourful glass "scales" - 24 d ifferent shades of red and green printed on the back of each individual pane by means of the silk­ screen technique. The panes are arranged on this 74 m long block so that there is a gradual transition from a dominance of red to a domi­ nance of green, reflecting the internal uti lisation - red for the fire brigade, green for the police but also the clay brickwork of the former Prus­ sian administration block and the surrounding greenery. The individual panes are fixed to a supporting framework of aluminium and can be opened where they pass in front of the win­ dows in the inner leaf. I ntended to provide shading when closed, they create a coloured glow in the white-painted interiors; but when open hardly any colouring is noticeable inside. QJ

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Example 25

Roof to tennis stadium

Hamburg, Germany, 1 997

Architects: Schweger + Partner, Hamburg Project team: Paul J . Schuler Marc Bogaczynski , Jutta Dulsen, Volker Petters, Gerhard Vester Structural engineers: Sobek + Rieger, Stuttgart

The Rothenbaum tennis stad ium in Hamburg has been provided with a flexible roof construc­ tion in order to provide protection against the elements, primarily for major tournaments. However, the aim was to retain the character of an open-air event. Erected separately from the existing facilities, the tensile structure spanning more than 1 00 m without intermed iate support is d ivided into two sections: a 1 7 m wide outer ring as a perma­ nent roof to the grandstand, and a 63 m open­ ing which can be closed if req uire d . Both roof sections are covered with a translucent, 1 .2 mm thick PVC-coated polyester membrane. But the roof elements suspended from the primary structure on the perimeter are covered with a transparent fluoroplastic material in order to improve the l ighting conditions. The construction essentially adheres to the spoked wheel principle. The outer compression ring of steel circular hol low sections is connect­ ed to the inner tension ring by 36 pairs of cables . Each pair is made up of an upper and lower group of cables held apart by so-called mid-air struts. From here, the cable "spokes" continue to the "hub" - positioned off-centre so that it does not cast a shadow on the tennis court - below which the folded membrane is stored. The synchronously operated motors can unfold the roof within five minutes. When closed, rainwater drains along a gutter positioned below the mid-air struts and is then pumped away by means of su bmersible pumps. When open, the folded roof membrane is protected against airborne poll ution and rain by a transparent covering of PMMA. ClJ

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G lossary: Physical parameters of materials

Physical parameters of materials Karsten Tichelmann, Patrik Jakob

Mechanical parameters Density p [kg/m3, kg/dm"l The density is the volume-related weight of a dry building material including pores and intermediate voids (mass per unit volume). For certain groups of building materials, e.g. concrete and masonry, density classes are used to help define material properties such as strength or ther­ mal conductivity. The relationship between the thermal conductivity and density of various building materials is given in tabular form in DIN 4 1 08-4 and DIN E N 1 2524. Weight density y [kN/m"l The weight density of a body designates the ratio of weight to volume. In contrast to density, the weight dens­ ity refers to the weight and not the mass, i.e. d ensity and weight density differ by the factor of gravitational acceler­ ation g = 9.81 N/kg. Compressive strength f, [N/mm'] The compressive strength defines the maximum accepta­ ble stress in a material subjected to a compression action. It is calculated by dividing the maximum accepta­ ble compressive force by the initial cross-section of the sample of material. Tensile strength f, [N/mm'] The tensile strength is the maximum acceptable stress in a material subjected to a tension action. It is calculated by dividing the maximum acceptable tensile force by the initial cross-section of the sample of material. Tensile bending strength fm [N/mm'] The tensile bending strength is the maximum acceptable stress at the failure state in a test specimen subjected to a bending action. It is calculated by dividing the maxi­ mum bending moment and the moment of resistance by the cross-section of the sample of material. The stand­ ards prescribe various tests to determine the tensile bending strength depending on the particular material.

Mohs hardness

Reference mineral

Tensile splitting strength Psz [N/mm'] The tensile splitting test is an indirect way of determining the tensile strength of stone types and building materials containing hydraulic binders. In contrast to the direct ten­ sile strength test, a cylindrical specimen is subjected to an increasing compression load, which generates tensile stresses perpendicular to the compressive stress. Once the tensile stresses exceed the cohesion (bonding forces between atoms or molecules), failure occurs. Modulus of elasticity E (Young's modulus) [N/mm'] The modulus of elasticity is a material parameter that describes the relationship between stress and strain (deformation, usually elongation) when a solid body is subjected to a mechanical action. It is defined as the rise in the stress-strain ratio within the elastic limit. The value of the modulus of elasticity increases with a material's resistance to deformation. In other words, a material with a high modulus of elasticity is rigid, a material with a low modulus is soft. Elongation at failure E. [-] The elongation at failure is a material property that speci­ fies by how much (in per cent) a material deforms plasti­ cally before the solid body fails. This means that the cohe­ sion within a solid body is overcome by the action of external forces, e.g. by destroying the internal microstruc­ ture or by neutralising the molecular bond. Mohs hardness H M [-] The Mohs scale of hardness is a relative, 1 0-part scale for measuring a material's resistance to abrasion (scratching) in which the next harder mineral scratches the preceding softer mineral (fig. E 1 . 1 ) . The scale extends from 1 (talc) to 1 0 (diamond). Brinell hardness H B [N/mm'] The Brinell hardness test is applied to soft to moderately hard metals such as unalloyed structural steels or alumini­ um alloys, to timber, and to materials with a non-uniform

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microstructure, e.g. cast iron. The test involves pressing a hard steel or carbide ball into the surface of the material under standard loading conditions and then measuring the resulting indentation. The Brinell hardness is calculat­ ed by dividing the test load by the area of the indentation. Vickers hardness HV [N/mm'] In the Vickers hardness test a regular, square-base 1 36° diamond pyramid is pressed into the surface of the mate­ rial. Like with the Brinell hardness test, the Vickers hard­ ness is calculated by dividing the test load by the area of the indentation. Pressure p [Pal The pressure p is a physical parameter specified in pas­ cals. Air pressure is the hydrostatic pressure of the air. This deSignates the weight of the column of air above a surface or a body. This weight is not present in a vacuum.

Thermodynamic parameters Melting point TSM [0C] The melting point is the temperature at which a material melts, i.e. changes from the solid to the liquid state. Boiling point TS [0C] The boiling point is the temperature at which a material boils, i .e. its vapour pressure is equal to that of the exter­ nal pressure and it changes from the liquid to the gase­ ous state. Thermal conductivity A. [W/mK] The thermal conductivity is a specific material property. It specifies the heat flow that passes through a 1 m thick layer of a material with a surface area of 1 m2 for a tem­ perature difference of 1 K. The lower the thermal conduc­ tivity, the better is the material's insulating capacity. The A.-value is based on laboratory measurements of the material when dry. Specific heat capacity c [J/kgK] The specific heat capacity specifies the quantity of heat required to raise the temperature of 1 kg of a material by 1 K. The specific heat capacity helps to specify whether a material is a good or poor heat storage medium. The higher the value of c, the more heat can be stored in the same mass of material. Heat storage capacity asp [Wh/m2K] The heat storage capacity provides information about the ability of building materials to store thermal energy. It is the product of the specific heat capacity c, the density p and the thickness d of the specific building material (QSP = c x p x d). As a rule, materials with a high insulating value exhibit a lower storage capacity than materials with a poor insulating value. A high storage capacity has a positive effect on the interior climate because tempera­ ture peaks can be levelled off and hence excessive tem­ perature fluctuations avoided.

G lossary: Physical parameters of materials

Coefficient of thermal expansion a [K-'] The coefficient of thermal expansion specifies by how much a solid body expands or contracts in relation to the overall length for a temperature change of 1 K over a range practical for building purposes (normally -50°C to +BO°C). Thermal transmittance U (U-value) [W/m'K] The U-value defines the quantity of heat that passes through 1 m' of a building component for a temperature difference of 1 K between the boundary layers of air on both sides of the component while taking into account the surface resistances between air and material. The U­ value is required for calculating the transmission heat losses. Total thermal resistance R [m'KIW] The total thermal resistance is made up of the thermal resistance of a component plus the internal and external surface resistances. It represents the inverse of the thermal transmittance.

Moisture-related parameters Water vapour diffusion resistance index IJ [-] The water vapour diffusion resistance index is a measure of the vapour-tightness of a building material. It is a com­ parative figure that specifies by how much a layer's resistance to water vapour diffusion is greater than that of an equally thick layer of air. The water vapour diffusion resistance of many building materials varies as the tem­ perature and moisture levels change. This results in maxi­ mum and minimum values for the water vapour diffusion resistance index (e.g. solid clay bricks: IJ = 5/1 0). Water vapour diffusion-equivalent air layer thickness s. (s. -value) [m] Like the A thermal conductivity, the IJ water vapour diffu­ sion resistance index is a pure material parameter not based on any particular thickness of material. Only when it is multiplied by the thickness of the building material do we obtain a reference to the diffusion resistance of the building component, which is designated the diffusion­ equivalent air layer thickness (s. = d x IJ ) . Water absorption coefficient w [kg/m'ho.5] The water absorption coefficient is a figure that describes the capacity of building materials and coatings to absorb water when in contact with water in its liquid state. Regu­ lar weighing of the samples under examination produces a graph of water absorption in relation to the length of immersion. Alternatively, the w,, -value is often specified, i.e. the water absorption after immersion for 24 hours. Volume-related moisture content 'P [-] The volume-related moisture content is the quotient (in per cent) of the volume of the vaporisable water and the

volume of the material under examination. The latter can be related to the moist or dry condition. Therefore, the moisVdry reference must always be stated with the respective moisture content. Mass-related moisture content u [-] The mass-related moisture content is the quotient (in per cent) of the mass of the vaporisable water and the mass of the material under examination. The latter can be relat­ ed to the moist or dry condition. Therefore, the moisVdry reference must always be stated with the respective moisture content. Equilibrium moisture content [-] (at 20°C and 65% relative humidity) The measured material moisture content ind icates how much water (in per cent) is present in a material. If the surrounding climate changes, the water content changes as well. The material moisture content at 20°C and 65% relative humidity, which ensues after a certain time, is known as the equilibrium moisture content. Swelling and shrinkage E [-] Swelling and shrinkage specify the change in volume (in per cent) of a material not under load during the absorp­ tion of water and drying out respectively. In doing so, it is assumed that the swel ling or shrinkage process is not influenced by any stresses acting in the material. In the case of inhomogeneous materials such as wood, we wit­ ness differences in the three principal directions: tangen­ tial, radial to the annual rings, and parallel to the grain.

Acoustic parameters Sound impedance per unit length r [kPa s/m'] The sound impedance per unit length is a material prop­ erty of a sound-absorbing building material that is not dependent on the thickness of the material. For insulation in cavities and voids in particular, the sound impedance per unit length should not be too low (> 5 kPa slm'). so that sound waves can be well absorbed. Sound absorption coefficient a, [-] A part of the kinetic energy in vibrations in gases, liquids and solids is converted irreversibly into heat. This proc­ ess is known as absorption. The sound absorption coeffi­ cient describes the ratio of non-reflected to incident sound energy. For total absorption, a, = 1 , for total reflec­ tion, a, = D. The sound absorption coefficient of a sound­ absorbing material depends on the frequency and is cal­ culated using one-third octave band filters in the frequen­ cy range 1 00-5000 Hz. Dynamic stiffness s [M N/m'] The dynamic stiffness is the resistance of a spring to a variable load action. Generally, the dynamic stiffness is greater than the stiffness due to a static loading action. In the case of sound-insulating systems, the spring is formed by, for example, an enclosed cushion of air between two covering leaves or the elastic insulating layer beneath a layer of screed.

Chemical parameters Fire resistance parameters Building materials class [A-B], combustibility class [A-F] The combustibility of a building material plays a key role in the outbreak and spread of a fire. D I N 4 1 02-1 allocates building materials to specific classes according to their behaviour in fire. The building materials in class A are incombustible. Building materials of class A1 must be made entirely of incombustible materials, whereas those of class A2 may contain small amounts of combustible constituents. Class B is for combustible materials and is further subdivided into not readily flammable (B1 ) . flam­ mable (B2) and highly flammable (B3) building materials. The European standard ( D I N EN 1 3501 - 1 ) has combusti­ bility classes A 1 and A2 for incombustible building mate­ rials. The combustible materials are allocated to classes B to F. In addition to behaviour in fire, the European clas­ sification system also regulates secondary effects due to fire. There are three classes for smoke release rate (s1 , s2, s3) and another three for occurrence of flaming dro­ pletslparticles (dO, d1 , d2). The classification can be car­ ried out accord ing to national or European standards (fig. E 1 .2). DIN 4 1 02 has been used in this book because the standardisation has not yet been fully harmonised.

pH value [-] The pH value is the measure of the "degree of acidity" of a building material. It corresponds to the negative base1 0 logarithm of the concentration of H 0+ ions. The neu­ 3 tral value is pH = 7, and acidic and alkaline constituents are then in equilibrium. The lower the pH value, the great­ er is the acid content of a building material.

Electrical parameters Electrical conductivity K [m/ I mm'] The ability of materials to conduct electricity is deter­ mined by the number and motion of the free electrons. The electrical conductivity of solid bodies has the varia­ tion range of 1 0" at room temperature. This variation range leads to classification in three electrical materials classes: conductors (metals), semiconductors (e.g. sili­ con) and non-conductors (insulators, e.g. ceramics). Electrical conductivity is the inverse of resistivity.

265

G lossary: Physical parameters of materials

Optical parameters Light transmittance t (optical transparency) [-] The light transmission of visible radiation (daylight) with wavelengths from 380 to 780 nm through transparent components plays a critical role in the illumination of an interior. The light transmittance is the parameter for this. It expresses the directly transmitted, visible radiation com­ ponent in the range of wavelengths of visible light related to the brightness sensitivity of the human eye. The light transmittance specified in per cent is the quo­ tient of the incident and emergent radiation after passing through a transparent building material. Total energy transmittance g (g-value) [-] The g-value is the total energy transmitted in the range of wavelengths from 300 to 2500 nm. This variable is required for interior climate calculations and is expressed in per cent. The total energy transmittance is made up of the direct transmission of solar radiation plus the heat emission of components absorbed in the glass in the form of heat radiation and convection to the inside. Reflectance p (reflection factor) [-] The reflectance is that part of the light incident on a sur­ face that is reflected by the surface back into the sur­ roundings. On very smooth surfaces, e . g . mi rrors, the light is reflected u niformly so that the angle of incidence is always equal to the angle of reflection. If the light is scattered in several directions, we speak of a diffuse reflection. Emissivity E [-] The radiation incident on a body is reflected, absorbed or transmitted. A body that absorbs all the radiation incident upon it is known as a "black body". Engineered surfaces absorb various wavelengths to different degrees and are known as pigments. The emissivity describes the heat radiated from a surface in relation to a "black body" at the

Building authority designation

Additional requirements Cl) "" o '" o c:

E

en

same temperature. A low emissivity means a low amount of heat radiation. Optical density (extinction) E [-] In optics, the extinction, or optical density, is a measure of the weakening of a radiation form (e.g. light) in a medi­ um. If 10 is the incident radiation and I the emergent radi­ ation (after passing through the medium), extinction E is defined as E = -log(I/l o) ' Extinction is the negative base1 0 logarithm of the light transmittance. Colour rendering index R [-] a Colour rendition is determined by the spectral distribution of light. The colour rendering index describes this proper­ ty, determined by means of a reference light source and diverse test colours. The higher the value of Ra the lower ' is the deviation of the object colour perceived visually in the light source concerned from the reference light source, e.g. daylight.

Parameters for concrete Characteristic strength J3WN [N/mm2] The J3w compressive strength of 200 mm cubes after 28 days (standard storage conditions) forms the basis for determining the characteristic strength. The compressive strength J3W28 of each cube must be at least equal to the characteristic strength J3WN • Classification in the associat­ ed concrete strength class is based on the characteristic strength. Strength class [-] The concrete strength class to Eurocode 2 makes use of two figures, e.g. C 20/25. The first figure designates the 5% fractile of the J3w compressive strength of a 300 mm long x 1 50 mm diameter cylinder and governs the design. The second figure designates the compres-

Combustibility class to DIN EN 13501-1

.f: en rJJ E - Cl) ca .! u

Building materials class to DIN 41 02-1

;:o ..g- :eco

c: -c a.

Incombustible

A1 A2 - s1 dO

Not readily flammable

B, C - s1 dO

A1 A2 B1

B, C - s3 dO B, C - s1 d2 B, C - s3 d2 Flammable

Highly flammable

D - s3 dO E D - s3 d2 E - d2 F

B2

B3 E 1 .2

266

sive strength of 1 50 mm cubes. The 5% fractile is the compressive strength value for which there is a 5% prob­ ability that the samples examined will not attain this value. Initial (suitability) test Before casting the concrete, a check is carried out to assess whether the intended concrete mix will actually achieve the properties required of the wet and hardened concrete. The conditions on the building site regarding, for example, plaCing methods and temperature, must be taken into account. ConSistency, p density of wet con­ crete and compressive strength are always checked, plus the water/cement ratio for concrete type B 1 1 . All the tests must be carried out with a wet concrete temperature of 1 5-22°C. In order to check the setting, the consistency is determined 1 0 and 45 minutes after adding the water. When using ready-mixed concrete, the initial test is car­ ried out directly in the supplier's QC laboratory. Quality test During placing of the concrete, a quality test must prove that the concrete mix complies with the specification and the properties required can be achieved continuously. The qual ity test relates to the properties of the wet and hardened concrete. Cement, aggregates and additives/ admixtures - the raw materials of the concrete - are sub­ ject to quality control measures, i.e. they are checked by the contractor's!supplier's QC laboratory and outside bodies. In the case of ready-mixed concrete it is not nec­ essary to check the raw materials because this is already carried out in the QC laboratory at the ready-mixed con­ crete works. For every test specimen and every test of consistency and water/cement ratio, the individual con­ crete samples must be taken from different mixer batches regularly over the complete period of placing the con­ crete. DIN 1 048 describes the test methods plus the pro­ duction and storage of test specimens.

Glossary: Physical parameters of materials

Parameters for bitumen Needle penetration [1/10 mm] The needle penetration specifies the hardness of the bitumen determined by the penetration depth of a needle with a diameter of 1 .01 mm at 25°C under a load of 1 .0 N over a period of 5 s in units of 1 /1 0 mm. Softening point (ring and ball) re] The softening point temperature is measured when the bitumen infill to a ring loaded by a steel ball has under­ gone a defined deformation due to a rise in temperature. Fraass breaking point [OC] The Fraass breaking point is defined as the temperature at which a layer of bitumen spread over a steel plate fractures or develops cracks under given conditions dur­ ing uniform cooling when the bitumen is bent.

Parameters for glass Bending strength of glass [N/mm"l The bending strength of glass is not a material property; its value is influenced by the properties of the surfaces. Even minor damage to the surface leads to a reduction in the bending strength. The consequence of this is that the term bending strength can only be defined statistical-

Iy by using a permissible value of the probability of fail­ ure. For a given stress, the probability of failure depends on the size of the surface subjected to tension and the duration of the action. Thermal stability of glass [0C] The thermal properties of glasses are grouped together under the heading of thermal stability. This is the maxi­ mum service temperature 1')ma< of toughened safety glass and the durabil ity with respect to temperature differences 61') over the surface of the pane. The known characteris­ tic values, which are also stated in various standards, are based on experience; a generally acknowledged, practi­ cal means of testing is not available at present.

Yield point (yield stress) Re [N/mm"l The yield point defines the limit to which ductile materials can be stretched without permanent plastic deformation when subjected to a uniaxial, non-moment tension action. If the yield point is exceeded, the material does not return to its original form upon releasing the load, i.e. a plastic elongation of the sample remains. Generally, it is not the yield stress, but rather the 0.2% proof stress RP 0.2 that is specified for engineering mate­ rials.

Parameters for metal

Proof stress Rp [N/mm"l The proof stress of a material is the mechanical stress at which a non-proportional elongation leads to a certain plastic deformation. The 0.01 % proof stress is known as the technical elastic limit. In practice the 0.2% proof stress (RP 0.2) or 1 % proof stress (RP 1 .0) are normally used.

Electrochemical series [-] The electrochemical series is a list of substances arranged according to the strength of their tendency to lose electrons (reducing agent) or attract electrons (oxi­ dising agent). Substances that exhibit a strong tendency to lose elec­ trons (e.g. sodium) are given a negative sign , those with a strong tendency to attract electrons (e.g. chlorine) are given a positive sign.

E 1 .1 E 1 .2 E 1 .3 E 1 .4

Parameter

Unit

Density p

[kg/m' ]

Wt. den. y

[N/m']

Energy

joule [J]

Pressure

Volume

pascal [Pal

[cm' ]

Temperature degree Celsius [0C]

Length

Area

metre [m]

square metre [m']

Further units

SI prefix

Conversion factors

p = yl ge'"h g ee"h = 9.81 N /kg y = p X gearlh watt-second [Ws] kilowatt-hour [kWh] calorie [cal] electron volt [eV] coal equivalent [SKE]

1 1 1 1 1

J= J= J= J= J=

1 Pa 1 Pa 1 Pa

litre [I] US barrel [bbl] imperial barrel [bbl] US gallon [gal] imperial gallon [gal]

1 000 cm' = 1 litre 1 litre = 6.290 x 1 0' US bbl 1 litre = 6.285 x 1 0' imp bbl 1 litre = 0.264 US gal 1 litre = 0.220 imp gal

kelvin [K] degree Fahrenheit [OF] inch [in] foot [ft] square inch [in'] square foo [ft']

= =

=

TCe,s,us TeelS,",

1 0.5 bar 9.87 x 1 0'· atm 1 45 x 1 0.6 psi

= =

TKelvin -273. 1 5 (T" h"oheo1 -32) / 1 .8

1 m = 39.370 in 1 m = 3.281 ft 1 m' 1 m'

=

=

Symbol

1 550 in' 1 0.764 ft' E 1 .3

Factor

yokto

Y

1 0'"

zepto

z

1 0'"

atto

a

1 0·'8 1 0.15

femto

1 Ws 2 . 778 x 1 0.7 kWh 0.239 x cal 6.242 X 1 0'8 eV 3.4 1 2 X 1 0.7 SKE

bar [bar] atmosphere [atm] pound per square inch [psi]

Mohs hardness scale Classification of fire behaviour Physical units of measurement and their conversion factors Conversion factors for SI prefixes

piko

P

1 0'"

nano

n

1 0'·

mikro

"

milli

m

1 0"

zenti

c

1 0"

dezi

d

1 0"

deka

da

1 0'

hekto

h

1 0'

1 0'·

kilo

k

1 0'

mega

M

1 06

giga

G

1 0·

tera

T

1 0"

peta

P

1 015

exa

E

1 0'8

zetta

Z

1 0"

yotta

y

1 0" E 1 .4

267

Glossary: Hazardous substances

Hazardous substances Alexander Rudolphi

Numerous public announcements concerning health risks, e.g. due to wood preservatives or asbestos, have in recent years brought hazardous substances to the atten­ tion of building developers and building occupants, and have turned those substances into another important planning aspect for architects. The most common hazardous substances are to be found in old buildings and are subject to national legislation, which can vary. Some pesticides such as DDT or PCP have been banned in Western Europe and Scandinavia since the 1 960s, but were still in use in Eastern Europe and the former Soviet Union until well into the 1 990s. Even a hazardous substance like asbestos, the use of which has been severely restricted in Europe and the USA since the 1 980s, is still being used by the building industry in Eastern Europe and, above all, in developing countries and in China. The same is true for PAHs with the carcinogenic substance benzoapyrene (BaP) as their reference substance and which were used in Western Europe until well into the 1 960s in floor adhesives, wood preservatives or asphalt finishes. This substance came to light as a problem in the 1 980s and from the 1 990s was excluded from almost all building products in western industrialised countries. It is frequently the case that certain hazardous sub­ stances are associated with certain countries and periods of time. For example, in former East Germany phenols and cresols, waste products from the chemicals industry, were used as binders in floor coverings and lightweight screeds. Old buildings therefore need to be approached with care, and a precise analysis of the existing fabric in terms of location and age is essential . In doing so, attention must be paid to the assessment and remediation regulations and legislation, which can vary from state to state in Ger­ many. In contrast to those hazardous substances acknowl­ edged as such and mostly regulated by government leg­ islation, newer problematic substances are characterised by the fact that damaging effects are surmised but have not yet been proved. They are therefore not (yet) subject to any restrictions and can be found in many building products. Hazardous substances in new buildings espe­ cially must therefore be given attention. A typical example of this group is naphthalene. Originally a widely used household chemical product, its use in glues and wood­ based products has been gradually reduced in Germany over recent decades. Current EU re-evaluations of the carcinogenic potential will lead to further restrictions, but this hazardous substance is still in use at present. Differ­ ent evaluations are also to be expected as a result of the European Biocidal Products Directive (98/8/EC) intro­ duced in 1 998. One of the requirements of this directive is that all manufacturers of building products should declare the presence of biocides in wood or other pre­ servatives. Such biocides are currently bein9 re-evaluat­ ed, i.e. a number of new individual bans are expected. Arsenic In pure form a metallic grey, non-toxic solid, arsenic has been used as a pesticide in the especially toxic trivalent

268

form of arsenic( l I l) oxide (white arsenic) and in the form of cuprous arsenide (also in wood preservatives). The use of arsenic salts (arsenitesiarsenates) has been banned in Germany since 1 963, the use of arsenic compounds in general since 1 974. Across the EU, the use of arsenic has been controlled more and more since 1 967 (with the last revisions in 2003) by an EU directive. Asbestos Asbestos is a generic term for fibrous minerals compris­ ing magnesium silicate, iron dioxide, calcium dioxide, aluminium dioxide and silicon dioxide. We distinguish between three main forms depending on the chemical composition: fibres of serpentine (chrysotile). of amphi­ boles (actinolite, amosite, anthophyllite, tremolite). and of hornblende. In the building industry, asbestos first proved to be an outstanding material with desirable qualities (incombustible, resistant to chemicals, electrical and ther­ mal insulation, elastic, tensile strength) . For these rea­ sons, it is frequently found in buildings built between 1 950 and 1 990, primarily for fire protection or as fibre reinforcement. Chrysotile is the most important form for building products. The toxic effects are due to the geometry of the mineral fibres, so-called inhalable fibres 5-500 IJm long and 1 -3 IJm thick (WHO definition). These are not soluble in pulmonary fluid and cause lung cancer (asbestosis). According to the German Asbestos Act of 1 991 , the import, use and production in Germany is essentially pro­ hibited. Demolition, refurbishment and maintenance work in buildings containing asbestos must be carried out according to the statutory provisions of the Hazardous Substances Act (TRGS 5 1 9) in order to protect the work­ ers, the local inhabitants and the environment. Loosely bonded applications, e.g. pipe lagging, seals or fire­ resistant mats, are assessed more critically than firmly bonded applications such as plaster or fibre-reinforced cement products, e.g. roofing and wall boards, pipes and floor tiles. Biocides This is a generic term for all kinds of products poisonous to pests (pesticides). fungi (fungicides). plants (herbi­ cides) and insects (insecticides). Biocides are used, e.g. in wood preservatives, textile finishes, to combat damage caused by animal and plant infestation, to protect against mould growth or as a preservative in dispersion coatings. CFCs Chlorofluorocarbons cause severe damage to the ozone layer. The production, marketing and in certain cases the use of some CFCs has been prohibited in Germany since 1 991 . The German legislation, however, is limited to 1 7 substances, e.g. trichlorofluoromethane ( R 1 1 ) . dichlorodi­ fluoromethane ( R 1 2) or chlorotrifluoromethane (R 1 3). Commercially used substances like H 1 201 halon or R 1 34a CFC also possess, respectively, 6300 or 3300 times the global warming potential of carbon dioxide and should therefore be avoided even though not covered by the legislation. CFCs are also used as blowing agents for insulating foams and as coolants. The disposal of refrig­ eration systems containing CFCs may only be carried out by authorised specialist companies. Coolants containing CFCs in a concentration of > 1 % by mass are no longer permitted. Insulating materials containing CFCs that are already installed do not need to be removed, but their disposal in some regions of Germany requires special controls and they must be classed as hazardous waste. DOT Dichlorodiphenyldichloroethane, a mixture of hydrocar­ bons and the by-products DDD and DDE, is a synthetic insecticide which is still used today in many countries. I n Germany, however, it has been banned since 1 972. DDT is essentially ecotoxic (i.e. damaging to the environment) for land-, air- and water-based creatures. Chronic health disorders have been observed in humans; the substances in DDT can lead to pulmonary oedemas and damage liver, kidneys, heart, bone marrow and nervous system. In the building industry, DDT is used as an active ingredient in wood preservatives.

Dioxins, furans In nature dioxins and furans are a widespread group of organic compounds with a system of two benzene rings plus additional oxygen compounds. In everyday lan­ guage the term dioxin covers about 75 polychlorinated (and polybrominated) dibenzodioxins (PCDD). some of them highly toxic. Similarly, the term furan covers poly­ chlorinated (and polybrominated) dibenzofurans (PCDF). Limit values for 1 7 of these substances were laid down in the 1 993 German Dioxin Act. In the building industry the main danger is i n the creation and removal of contaminat­ ed residues after fires when the halogens chlorine and bromine have been used in synthetic materials (e.g. as flame retardants). The risks can only be reduced by avoiding such products. Formaldehyde This colourless gas with the chemical designation meth­ anal is a simple compound of carbon, oxygen and hydro­ gen. This pungent-smelling substance belongs to the VOC group, is highly reactive and readily soluble in water. Contact with formaldehyde leads to symptoms in humans such as irritation to the eyes, bronchial problems and headaches. In the building industry formaldehyde is primarily used as a binder in wood-based boards, which can still give off formaldehyde even after 20 years. It is also used in synthetic resins, coatings or chemical addi­ tives, e.g. in self-levelling screeds. Owing to the massive and frequent health disorders, the content of formalde­ hyde in new wood-based boards has been limited by legislation in Germany (1 996 Chemicals Prohibition Act, DIBt Formaldehyde Directive). The following recommended values apply to the air in habitable rooms:

Recommended value of German Federal Health Organisation/German Environmental Agency 1 977/1990: 0.1 ppm (corresponds to 1 20 IJg/m3) . Target value for refurbishment work: 0.05 ppm (corre­ sponds to 60 IJg/m3)

•

Mineral hydrocarbons This is the group of liquid distillation products obtained from petroleum or coal. Oil contamination (diesel, heating oil, lubricants) in residential buildings is undesirable sim­ ply for regions of hygiene, and in the case of fresh con­ tamination there is also the question of exposure to un­ pleasant odours. Apart from that, mineral building com­ ponents contaminated with oil lead to enormous difficul­ ties because oil separates materials and hence breaks down the bonds. A mineral hydrocarbon content < 1 00 mg per kg of building material is regarded as harmless. But contamination ;;, 1 000 mg per kg of material represents a demolition project with waste that requires special con­ trols. Building components or materials contaminated with oil should always be completely removed from interiors. MVOCs Microbial volatile organic compounds are volatile bio­ organic compounds - alcohols, keytones, esters and aro­ matic compounds - produced by the metabolic process­ es of fungi, e.g. mould. Some health problems are attrib­ uted to MVOC contamination in buildings. The MVOC spectra of many mould types have not yet been fully investigated. However, remediation and treatment is car­ ried out anyway owing to the presence of the mould that inevitably accompanies MVOC. PAHs The polycyclic aromatic hydrocarbons group contains more than 1 00 individual compounds which are formed by the heating or combustion of organic materials with an oxygen deficit, e.g. vehicie exhausts or industrial pro­ cesses. They never occur as individual substances but always in the form of complex mixtures. Measurement in solid materials usually cover 16 individual PAHs stipUlat­ ed by the USA's Environment Protection Agency; the ref­ erence substance is BaP (benzoapyrene). In high concentrations, PAHs are usually present in prod­ ucts manufactured using coal tars, coal-tar oils and coal­ tar pitches. These include carbolineum, asphalt tiles and tar adhesive. Bitumen (which is also obtained through the

G lossary: Hazardous substances

distillation of petroleum) as well - but only in traces, unless mixed with tar. Especially critical are paints based on creosote used for waterproofing purposes (general waterproofing, wet interior areas, roofs), papers soaked in creosote (roofing felt, insulating materials for power cables and heating pipes), adhesive for wood-block floor­ ing, mastic asphalt and wood preservatives. Numerous PAHs have been proved to be carcinogenic, mutagenic, toxic to the immune system and the liver, and to irritate mucous membranes. PCBs Polychlorinated biphenyls, a group of 209 chemical com­ pounds made up of biphenyl and chlorine (so-called PCB congeners), have been manufactured since about 1 929. Owing to their technically interesting properties - not readily flammable, hardwearing and resistant to acids and alkalis - they have been used in many applications, e.g. as electrical insulators in transformers and capaci­ tors, as plasticisers in synthetic materials, in sealin9 materials for expansion joints, and in hydraulic systems. Following severe mass poisonings (1 968 in Japan, 1 969 in Taiwan), the production and use of PCBs has been banned (with a few exceptions) in Germany since 1 989. However, the use of capacitors containing PCBs was not finally prohibited until 2000, which means that these sub­ stances can even be found i n modern buildin9s. PCBs and equipment containing PCBs must be removed by 201 1 at the latest (apart from a few exceptions). PCP Pentachlorophenol, a compound belonging to the chlo­ rophenols group, is a colourless solid in its normal state and acts as a fungicide. Until it was banned in Germany in 1 989, it was used in disinfectants and wood preserva­ tives. In other countries it is still used in the textiles and cosmetics industries. PCP is ecotoxic. Toxicity in humans has been observed, but has not yet been fully investigat­ ed. It can lead to pulmonary oedemas, also liver, kidney, heart and bone marrow disorders. It is also a neurotoxin. Radon Radon is a noble gas with exclusively radioactive iso­ topes. As an i ntermediate product of the decay chain of uranium and radium, it escapes naturally from the soil and infiltrates buildings from below. I n newer buildings in particular, which for energy efficiency reasons are built especially airtight. radon can accumulate i n the i nterior air and lead to lung cancer. The soil contamination varies considerably from region to region; in Germany the Fed­ eral Office for Radiation Protection maintains a register of

natural radon levels. The bases of buildings affected must be sealed with a radon-proof flexible synthetic or bitumen sheeting. Protective measures are required when the radon concentration in the building exceeds 250 Bq/ m" The basement storeys must be sealed tighter than the storeys above and must be ventilated separately. Synthetic mineral fibres These fibres are manufactured from stone or glass melts. They are used in large quantities mainly in fire protection, sound insulation and thermal insulation products. Like asbestos, up until about 1 995 products with synthetic mineral fibres contained longitudinally fractured fibres with critical dimensions (diameter < 3 �m, length > 5 �m, length-diameter ratio > 3) which can infiltrate the lung alveoli and cause cancer and other lung disorders. This risk is heightened by those fibres that are not soluble in pulmonary fluid and which can accumulate over time. In German legislation synthetic mineral fibres with such properties have been classified as carcinogenic since 1 995. The assessment is carried out by means of the bio­ persistence (solubility) which is influenced by the formu­ lation of the melt among other things. As a unit of mea­ surement, the so-called carcinogenicity index (KI) has been introduced. · Substances with KI < 30 are regarded as carcinogenic. • Substances with KI 30-40 are suspected of having a carcinogenic potential. · Substances with KI > 40 are classified as not carcino­ genic.

The groups for the TVOC match the chemical substance group designations (fig. E 2 . 1 ) . Accord ing t o a recommendation of the German Environ­ mental Agency, a value < 0.3 mg/m3 internal air is desira­ ble for the TVOC concentration in interiors. In new build­ ings the TVOC concentration should not exceed 1-2 mg/m3 internal air in the first year. Exceptions to this are indivi­ dual substances within the VOC catalogue - naphtha­ lene, styrene, toluene or dichloromethane - which are subject to a specific ruling by Germany's I nternal Air Commission. Wood preservatives Organic wood preservatives contain pesticides and fun­ gicides. The most important health hazards are caused by PAH, DOT, PCP, lindane or xylasan, and their use in Germany is now prohibited. Modern organic preserva­ tives contain specific active substances such as propico­ nazol, dichlofluanid or flufenoxuron. Preservative salts contain primarily boron salts and borates plus copper and chromium salts. A total of about 60 different toxic substances are used. Of course, modern preservatives also represent a health hazard; the risks of uncontrolled damage are, however, much lower than in the past thanks to better adherence to regulations. Old preserva­ tive treatments should always be analysed and assessed. The contamination varies considerably from region to region; in former East Germany and in Eastern Europe concentrations in roof structures of up to 10 000 mg ( = 10 g) DOT per kg of timber can be found on the surface.

I n the case of pre-1 995 synthetic mineral fibre products, carcinogenic effects must always be assumed. The industrial safety regulations specific to each federal state in Germany must be observed when handling such products.

vacs Volatile organic compounds are soluble and hence capa­ ble of causing emissions. We distinguish between four different groups according to their boiling points: · • • ·

WOC (very volatile organic compounds): 0-50°C VOC: 50-250°C SVOC (semi-volatile organic compounds): 250-380°C TVOC (total volatile organic compounds)

This covers all substances from very volatile organic sol­ vents to semi-volatile plasticizers used in synthetic mate­ rials, fatty acids, etc. In the customary measuring proce­ dure about 1 60-180 individual substances are evaluated.

vac substance class

Most frequent sources of emissions

Aliphates

All products containing solvents, e.g. paints, adhesives; white spirit and thinners, cleaning agents, carpets, isoaliphates in natural resin varnishes.

Aromates

Products containing solvents, e.g. nitrocellulose lacquer, synthetic resin paints, adhesives; thinners, carpets.

Styrene

Insulating materials, coatings based on unsaturated polyester resins, carpets, paints.

Heterocyclene

Synthetic resin paints, solvents, carpets.

Halogen hydrocarbons

Strippers, blowing agents in insulating foams.

Terpenes

Wood, wood-based products, natural and alkyd resin paints, stove enamel.

Aldehydes

Drying oils, alkyd resins, linoleum floor coverings.

Formaldehyde

Wood-based products, paints, urea-formaldehyde foams, insulating materials, filler compounds, furniture, textiles.

Ketones

Water- and solvent-based products, e.g. paints, adhesives, strippers.

Alcohols and esters of monovalent alcohols

Water- and solvent-based products, e.g. paints, adhesives, strippers; polyurethane foams, filler compounds.

Glycols

Water-based products, e . g . acrylic paints, adhesives, joint sealants; stove enamel, wood stains, dispersion paints; as plasticiser additive in various synthetic materials and wood stains.

Pyrrolidone derivatives

Strippers, paints, water-based paints.

Trimeric isobutylenes

Carpets (foam-backed), all products containing rubber.

Phthalates

Plasticisers in latex and other paints, adhesives, varnishes, soft floor coverings, carpets, synthetic materials.

Biocides

Timber preservative, natural coverings, leather, carpets.

Flame retardants

Carpets, textile furnishings, intumescent paints. E 2.1

269

Statutory instruments, d i rectives, standards

Statutory instruments, directives, standards The EU has issued directives for a number o f products, the particular aim of which is to ensure the safety and health of users. These directives must be implemented in the member states in the form of compulsory legislation and regulations. The directives themselves do not contain any technical details, but instead lay down the requisite, underlying requirements. The corresponding technical values are specified in associated sets of technical rules (e.g. codes of practice) and in the form of EN standards harmonised throughout Europe. Generally, the technical rules provide advice and infor­ mation for everyday activities. They are not statutory instruments, but rather give users a decision-making aid, a guideline for implementing technical procedures cor­ rectly and/or practical information for turning legislation i nto practice. The use of the technical rules is not compul­ sory; only when they have been included in government legislation or other statutory instruments do they become mandatory, or the parties to a contract include them in their conditions. I n Germany the technical rules include DIN standards, VDI directives and other publ ications such as the Techni­ cal Rules for Hazardous Substances. The standards are divided into product, application and testing standards. They often relate to just one specific group of materials or products, and are based on the corresponding testing and calculation methods for the respective materials and components. The latest edition of a standard - which should correspond with the state of the art - always applies. A new or revised standard is first published as a draft for public discussion before (with revisions) it is finally adopted as a valid standard. The origin and area of influence of a standard can be gleaned from its designation: DIN plus number (e.g. DIN 4 1 08) is essentially a national document (drafts are designated with "E" and preliminary standards with "V"). DIN EN plus number (e.g. DIN EN 572) is a German edition of a European standard - drawn u p by the European Standardisation Organisation CEN - that has been adopted without amendments. DIN EN ISO (e.g. DIN EN ISO 1 8064) is a standard with national, European and worldwide influence. Based on a standard from the International Standardi­ sation Organisation ISO, a European standard was drawn up, which was then adopted as a D I N standard. DIN ISO (e.g. D I N ISO 21 930) is a German edition of an ISO standard that has been adopted without amendments. The following compilation represents a selection of statu­ tory instruments, directives and standards that reflects the state of the art regarding building materials and build­ ing material applications as of September 2005. Part A

D I N 398 Granulated slag aggregate concrete blocks. 1 976-6 D I N V 4 1 65 Autoclaved aerated concrete blocks and flat elements. 2003-6 DIN 4 1 66 Autoclaved aerated concrete slabs and panels. 1 997- 1 0 D I N V 1 8 1 52 Lightweight concrete solid bricks and blocks. 2003-1 0 DIN V 1 8 1 53 Normal-weight concrete masonry units. 2003- 1 0 D I N E N 520 Gypsum blocks - Definitions, requirements and test methods. 2005-3 D I N EN 1 2859 Gypsum blocks. 2001 - 1 1 D I N 1 81 8 1 (draft standard) Gypsum plasterboards for building construction. 2004-8 D I N V 1 8550 Plasteringirendering and plasteringirender­ ing systems. 2005-4 DIN EN 998-1 Specification for mortar for masonry ­ Part 1 : Rendering and plastering mortar. 2003-9 D I N EN 998-2 Specification for mortar for masonry ­ Part 2: Masonry mortar. 2003-9 D I N 4 1 02 Fire behaviour of building materials and build­ ing components. 1 998-5

Part B

Bituminous materials DIN EN 1 2597 Bitumen and bituminous binders ­ Terminology. 2001 - 1 DIN EN 1 2591 Bitumen a n d bituminous binders ­ Specifications for paving-grade bitumen. 2000-4 D I N 1 995-4 (draft standard) Bitumen and bituminous binders - Requirements for the binders Part 4: Petroleum cut-back bitumen. 2005-1 D I N 1 8 1 95 Waterproofing of buildings and structures. 2000-8 D I N 52 1 30 Bitumen sheeting for waterproofing of roofs. 1 995-1 1 DIN 52 1 31 Bitumen waterproof sheeting for fusion weld­ ing. 1 995- 1 1 DIN 521 32 Polymer bitumen sheeting for waterproofing of roofs. 1 996-5 D I N 5 2 1 33 Polymer bitumen waterproof sheeting for fusion welding. 1 995- 1 1 D I N 52 1 43 Bitumen roofing felt with glass fleece base. 1 985-8 DIN 1 8 1 90-4 Waterproof sheeting for the waterproofing of buildings; waterproof sheeting with inlay of metal foil. 1 992-1 0

Properties of building materials

Stone D I N 4 1 08 Thermal protection and energy economy in buildings 2003-7 D I N EN 1 2524 Building materials and products - hygro­ thermal properties - tabulated design values. 2000-7 Loam DIN 4022-3 Subsoil and groundwater; designation and description of soil types and rock; borehole log for bor­ ing in soil (loose rock) by continuous extraction of cores. 1 982-5 D I N 5261 1 Determination of thermal resistance of build­ ing elements. 1 99 1 - 1 D I N 5261 2 Determination o f thermal conductivity b y the guarded hot plate apparatus. 1 979-9 Ceramic materials DIN 1 05 Clay bricks. 1 984-5 DIN 41 72 Modular coordination in building construction. 1 955-7 DIN 278 Hollow clay tiles (Hourdis) and hol low bricks, statically loaded. 1 987-9 D I N 4 1 59 Floor bricks and plasterboards, statically active. 1 999- 1 0 D I N 4 1 60 Bricks for floors, statically inactive. 2000-4 D I N EN 539 Clay roofing tiles for discontinuous laying. 1 998-7 DIN EN 295 Vitrified clay pipes and fittings and pipe joints for drains and sewers. 1 999-5 DIN EN 1 44 1 1 Ceramic tiles - Definitions, classification, characteristics and markin g . 2004-3 D I N 1 8 1 56 Materials used for the application of ceramic tiling by the thin bed method. 1 980-7 D I N 4 1 08 Thermal protection and energy economy in buildings. 2003-7

Materials and architecture

The critical path to sustainable construction SIA Documentation D 01 23 - Construction of buildings according to ecological aspects. SIA Documentation D 0200 SNARC - System for assess­ ing the environmental sustainability of architectural projects. 2004 SIA 480 Economic viability calculation for investments in buildings. 2004 Criteria for the selection of building materials DIN EN ISO 1 4040 Environmental management - Life cycle assessment - Principles and framework. 1 997-8 DIN EN ISO 1 4041 Environmental management - Life cycle assessment - Goal and scope definition and life cycle inventory analysis. 1 998- 1 1 DIN EN ISO 1 4042 Environmental management - Life cycle assessment - Life cycle impact assessment. 2000-7 D I N EN ISO 1 4043 Environmental management - Life cycle assessment - Life cycle interpretation. 2000-7

270

ISO 21 930: Sustainable building - Environmental declara­ tion of building products ISO 2 1 931 : Sustainable building - Assessment of impact from buildings ISO 2 1 932: Buildings and constructed assets - Terminol­ ogy related to sustainability D I N 276 Building costs. 1 993-6 D I N EN 1 3829 Thermal performance of buildings - Deter­ mination of air permeability of buildings - Fan pressuri­ sation method. 200 1 - 1 D I N EN ISO 1 02 1 1 Thermal bridges in building construc­ tion - Heat flows and surface temperatures - Part 1 : General calculation methods. 1 995- 1 1 DIN EN ISO 7730 Ergonomics of the thermal environment - Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort. 1 995-9 SIA 1 80 Thermal insulation and moisture control in build­ ings. 1 999 D I N V ENV 1 34 1 9 Building products - Determination of the emission of volatile organic compounds. 1 999- 1 0 ISO/TC/59

Building materials with mineral binders DIN 1 1 68 Gypsum for building. 1 986-1 DIN EN 459 Building lime. 2002-2 DIN EN 1 97 Cement. 2004-8 DIN EN 1 3279 Gypsum binders and gypsum plasters. 1 998-7 D I N EN 206-1 Concrete - Part 1 : Specification, perform­ ance, production and conformity. 2001-7 DIN 4226 Aggregates for concrete. 200 1 -7 D I N EN 934 Admixtures for concrete, mortar and grout. 2005-6 D I N EN 1 2878 (draft standard) Pigments for colouring of building materials based on cement and/or lime Specifications and methods of test. 2003-1 2 DIN 1 045 Structural use of concrete; design and construction. 2001-7 DIN 1 053 Masonry. 1 996- 1 1 D I N EN 771 Specification for masonry units. 2005-5 D I N V 1 06 Sand-lime bricks and blocks. 2003-2

Wood and wood-based products D I N EN 350 Durability of wood and wood based products. 1 994- 1 0 D I N E N 338 Timber structures - Strength classes. 2003-9 DIN EN 1 9 1 2 Structural timber - Strength classes ­ Assignment of visual grades and species. 2005-3 DIN 4074-2 Building timber for wood building compo­ nents; quality conditions for building logs (softwood). 1 958- 1 2 D I N 4074-3 Strength grading of wood - Part 3 : Grading machines for sawn timber, requirements and testing. 2003-6 D I N 1 052 Timber structures. 2004-8 D I N EN 1 3986 Wood-based panels for use in construction. 2005-3 DIN EN 3 1 2 Particleboards. 2003- 1 1 D I N EN 622 Fibreboards - Specifications. 2003-9 D I N EN 1 4755 (draft standard) Extruded particle boards Specifications. 2006-1 D I N EN 1 3 1 71 Thermal insulation products for buildings ­ Factory made wood fibre (WF) products - Specification. 2004-8 D I N 68800-2 Protection of timber - Part 2: Preventive con­ structional measures in buildings. 1 996-5 D I N 68800-3 Protection of timber - Part 3: Protection of timber; preventive chemical protection . 1 990-4 D I N 4 1 02 Fire behaviour of building materials and build­ ing components. 1 998-5 DIN EN 1 3501 Fire classification of construction products and building elements. 2002-6 Metal D I N EN 1 0027 (draft standard) Designation systems for steels. 200 1 -8

Statutory instruments, directives, standards

DIN EN 1 0025 Hot-rolled products of non-alloy structural steels. 2005-2 DIN EN 1 1 79 Zinc and zinc alloys - Primary zinc. 2003-9 DIN EN 485-2 Aluminium and aluminium alloys - Sheet, strip and plate - Part 2: Mechanical properties. 2004-9 Glass DIN 1 249 Glass for use in buildin9 construction. 1 986-9 DIN EN 572 Glass in building - Basic soda lime silicate glass products. 2004-9 DIN EN 1 3022 (draft standard) Glass in building ­ Structural sealant glazing. 2003-4 DIN EN 1 4449 (draft standard) Glass in building ­ Laminated glass and laminated safety glass. 2002-7 DIN EN ISO 1 0 077 (draft standard) Thermal performance of windows, doors and shutters - Calculation of thermal transmittance. Synthetic materials DIN EN ISO 1 043 Plastics - Symbols and abbreviated terms. 2002-6 DIN ISO 1 629 Rubber and latices - Nomenclature. 2004-1 1 DIN EN ISO 1 8064 Thermoplastic elastomers - Nomenclature and abbreviated terms. 2005-5 DIN 1 6780 Plastic moulding materials. 1 988-1 DIN 7726 Cellular materials. 1 982-5 DIN EN 923 Adhesives - Terms and definitions. 1 998-5 DIN 4 1 02 Fire behaviour of building materials and building components. 1 998-5 Maximum working place concentrations and biological tolerance values for substances. Deutsche Forschungs­ gesellschaft DFG, Weinheim TRGS Technical Rules for Hazardous Substances. Feder­ al Ministry of Industry and Employment. 2004-3 Life cycle assessments DIN EN ISO 1 4040 Environmental management - Life cycle assessment - Principles and framework. 1 997-8 DIN EN ISO 1 4041 Environmental management - Life cycle assessment - Goal and scope definition and life cycle inventory analysis. 1 998-1 1 DIN EN ISO 1 4042 Environmental management - Life cycle assessment - Life cycle impact assessment. 2000-7 DIN EN ISO 1 4043 Environmental management - Life cycle assessment - Life cycle interpretation. 2000-7

Part C

Applications of building materials

The building envelope DIN 1 053 Masonry. 1 996- 1 1 DIN V 18 1 53 Normal-weight concrete masonry units. 2003-1 0 DIN 1 8 5 1 6- 1 Cladding for external walls, ventilated at rear - Part 1 : Requirements, principles of testing. 1 999- 1 2 DIN 1 8 51 6-3 Cladding for external walls, ventilated at rear - Part 3: Natural stone. 1 999- 1 2 D I N 1 8 51 6-4 Cladding for external walls at rear - Part 4 : tempered safety glass. 1 990-2 DIN 1 249 Glass for use in building construction. 1 986-9 DIN EN 1 3022 (draft standard) Glass in building ­ Structural sealant glazing. 2003-4 TRAV Technical directive for the use of glass in safety barriers. 2003-1 TRLV Technical directive for the use of glazing carried on linear supports. 1 998-9 DIN EN 350 Durability of wood and wood based prod­ ucts. 1 994- 1 0 DIN 68800-3 Protection of timber - Part 3 : Protection of timber; preventive chemical protection. 1 990-4 DIN 1 7440 Stainless steels. 2001-3 DIN 1 8338 Contract procedures for building works ­ Part C: General technical specifications for building works; Roof covering and roof sealing works. 2002-1 2 DIN 681 1 9 Wood shingles. 1 996-9 DIN EN 1 2326 Slate and stone products for discontinuous roofing and cladding. 2004-1 1 DIN EN 539 Clay roofing tiles for discontinuous laying. 1 998-7

D I N EN 1 304 Clay roofing tiles for discontinuous laying. 2005-7 D I N EN 490 Concrete roofin g tiles and fittings. 2005-3 D I N EN 494 Fibre-cement profiled sheets and their fittings for roofing. 1 999-7 D I N EN 534 Corrugated bitumen sheets. 1 998- 1 0 D I N EN 485-2 Aluminium and aluminium alloys - Sheet, strip and plate - Part 2: Mechanical properties. 2004-9 D I N EN 988 Zinc and zinc alloys - Specification for rolled flat products for building. 1 996-8 D I N EN 1 1 72 Copper and copper alloys - Sheet and strip for building purposes. 1 996- 1 0 D I N 1 8807 Trapezoidal sheeting i n building; trapezoidal steel sheeting. 1 987-6 DIN 1 8 1 95 Waterproofing of buildings and structures. 2000-8 D I N 1 8531 -1 Waterproofing of roofs - Sealings for non­ utilised roofs - Part 1 : Terms and definitions, require­ ments, design principles. 2005- 1 1 D I N EN 1 3967 Flexible sheets for waterproofing - Plastic and rubber damp-proof sheets including plastic and rubber basement tanking sheet. 2005-3 D I N EN 1 3969 Flexible sheets for waterproofing ­ Bitumen damp-proof sheets including bitumen base­ ment tanking sheets. 2005-2 D I N 7864 Sheets of elastomers for waterproofing. 1 984-4 D I N 1 6729 Ethylene copolymer bitumen (ECB) plastic roofin g sheeting and plastic sealing sheeting. 1 984-9 D I N 1 6730 Plasticised polyvinyl chloride (PVC-P) roofing felt incompatible with bitumen . 1 986- 1 2 D I N 1 6731 Polyisobutylene (PI B) roofing felt with backing. 1 986- 1 2 D I N 1 6737 Chlorinated polyethylene (PE-C) roofing felt and waterproofing sheet with woven fabric inner layer. 1 986-1 2 D I N 1 6935 Polyisobutylene (PIB) waterproofing sheet. 1 986- 1 2 D I N 1 6937 Plasticised polyvinyl chloride (PVC-P) water­ proofing sheet compatible with bitumen. 1 986- 1 2 D I N 52 1 28 Bituminous roof sheeting with felt core. 1 977-3 D I N 521 29 Uncoated bitumen saturated sheeting. 1 993- 1 1 D I N 521 30 Bitumen sheeting for waterproofing of roofs. 1 995- 1 1 D I N 52 1 3 1 Bitumen waterproof sheeting for fusion weld­ ing. 1 995- 1 1 D I N 5 2 1 32 Polymer bitumen sheeting for waterproofing of roofs. 1 996-5 D I N 52 1 33 Polymer bitumen waterproof sheeting for fusion welding. 1 995- 1 1 D I N 1 81 90-4 Waterproof sheeting for the waterproofing of buildings; waterproof sheeting with inlay of metal foil. 1 992-1 0 D I N 521 4 1 Glass-fibre fleece as layer for roof and water­ proof sheeting. 1 980- 1 2 D I N 60000 Textiles, basic terms and definitions. 1 969-1 D I N 4 1 08 Thermal protection and energy economy in buildings. 2003-7 D I N 4 1 02 Fire behaviour of building materials and build­ ing components. 1 998-5 D I N EN 1 3501 Fire classification of construction products and building elements. 2002-6 Insulating and sealing D I N EN 1 4063 Thermal insulation materials and products. 2004- 1 1 D I N EN 1 3 1 62 Thermal insulation products for buildings ­ Factory-made mineral wool (MW) products. 2001 - 1 0 D I N E N 1 3 1 63 Thermal insulation products for buildings ­ Factory-made products of expanded polystyrene (EPS). 2001 - 1 0 D I N EN 1 3 1 64 Thermal insulation products for buildings ­ Factory-made products of extruded polystyrene foam (XPS) . 2001 - 1 0 D I N E N 1 3 1 65 Thermal insulation products for buildings ­ Factory-made rigid polyurethane foam (PUR) products. 2005-2 D I N EN 1 3 1 67 Thermal insulation products for buildings ­ Factory-made cellular glass (CG) products. 2001 - 1 0 D I N EN 1 3 1 68 Thermal insulation products for buildings ­ Factory-made wood wool (WW) products. 2001 - 1 0 D I N EN 1 3 1 69 Thermal insulation products for buildings -

Factory-made products of expanded perlite (EPB). 2001 - 1 0 D I N EN 1 31 70 Thermal insulation products for buildings ­ Factory-made products of expanded cork (ICB). 2001 - 1 0 DIN EN 1 3 1 71 Thermal insulation products for buildings Factory-made wood fibre (WF) products. 200 1 - 1 0 D I N EN 1 8 1 65 Fibre insulation materials. 200 1 -9 D I N EN 1 3 1 7 1 /A 1 Thermal insulation products for build­ ings - Factory-made wood fibre (WF) products. 2004-8 D I N 1 8 1 95 Waterproofing of buildings and structures. 2000-8 D I N 1 8540 Sealing of exterior wall joints in building using joint sealants. 1 995-2 D I N EN 26927 Building construction; jointing products; sealants; vocabulary. 1 991 -5 D I N 52460 Sealing and glazing - Terms. 2000-2 D I N 7865 Elastomeric joint sealing strip for sealing joints in concrete. 1 982-2 D I N 1 8541 (draft standard) Thermoplastic water stops for sealing joints in in situ concrete. 2005-3 ETAG 005 Guideline for European Technical Approval of liquid-applied roof waterproofing kits. D I N EN 1 4891 (draft standard) Liquid-applied waterproof­ ing membranes for use beneath ceramic tiling. 2004-5 D I N 4 1 08 Thermal protection and energy economy in buildings. 2003-7 Building services D I N 1 988 Drinking water supply systems; general (DVGW code of practice). 1 988- 1 2 D I N EN 806-1 Specifications for installations inside build­ ings conveying water for human consumption - Part 1 : General. 2001 - 1 2 D I N EN 806-2 Specification for installations inside build­ ings conveying water for human consumption - Part 2: Design. 2005-6 DIN EN 1 2056 Gravity drainage systems inside buildings. 2001 - 1 D I N EN 752 Drain a n d sewer systems outside buildings. 2005-1 0 D I N 1 80 1 5 Electrical installations in residential buildings. 2002-9 D I N 1 946 Ventilation and air conditioning. 1 998- 1 0 Walls D I N EN 771 Specification for masonry units. 2005-5 D I N V 1 06 Sand-lime bricks and blocks. 2003-2 D I N 1 8 332 Contract procedures for building works ­ Part C: General technical specifications for building works; ashlar works. 2002-1 1 D I N V 4 1 65 Autoclaved aerated concrete blocks and flat elements. 2003-6 D I N 4 1 03 Internal non-load bearing partitions. 1 988- 1 1 D I N EN 520 Gypsum plaster boards - Definitions, require­ ments and test methods. 2005-3 D I N 1 81 8 1 (draft standard) Gypsum plasterboards for building construction. 2004-8 D I N EN 1 2859 Gypsum blocks. 2001 - 1 1 D I N EN 1 39 1 5 Prefabricated gypsum wallboard panels. 2001 - 1 D I N EN 1 4566 (draft standard) Mechanical fasteners for gypsum p lasterboard systems. 2002- 1 1 D I N EN 1 4 1 95 Metal framing components for gypsum plasterboard systems. 2005-5 D I N EN 1 3986 Wood-based panels for use in construction. 2005-3 D I N EN 31 2 Particleboards. 2003-1 1 D I N EN 622 Fi breboards - Specifications. 1 997-8 D I N EN 1 4755 (draft standard) Extruded particleboards ­ Specifications. 2006-1 D I N 68762 Chipboard for special purposes in buildin9 construction. 1 982-3 D I N 1 249 Glass for use in buildin9 construction. 1 986-9 D I N EN 1 2725 Glass in building - Glass block walls. 1 997-4 D I N 4 1 02 Fire behaviour of building materials and build­ ing components. 1 998-5 DIN 4 1 09-1 0 (draft standard) Sound insulation in build­ ings - Part 1 0: Proposals for improved sound insulation for housing. 2000-6

271

Statutory instruments, directives, standards / Bibliography

Intermediate floors DIN 1 045 Structural use of concrete; design and con­ struction . 2001-7 DIN 4223 Reinforced roofing slabs and ceiling tiles of steam-cured aerated and foamed concrete. 2003- 1 2 DIN 68762 Chipboard for special purposes i n building construction. 1 982-3 DIN 4 1 2 1 Hanging wire-plaster ceilings. 1 987-7 DIN 4 1 02 Fire behaviour of building materials and build­ ing components. 1 998-5 Floors DIN 1 8560 Floor screeds in building construction. 2004-4 DIN EN 1 38 1 3 Screed material and floor screeds. 2003-1 DIN 1 8560-2 Floor screeds in building construction Part 2: Floor screeds and heating floor screeds on insu­ lation layers. 2004-4 DIN EN 1 3756 Wood flooring - Terminology. 2003-4 D I N EN 1 3329 Laminate floor coverings. 2000-9 D I N 68771 Sub-floors of wood chipboards. 1 973-9 D I N EN 1 4354 Wood-based panels - Wood veneer floor covering. 2005-3 DIN EN 1 4085 Resilient floor coverings. 2003-5 DIN EN 1 4041 Resilient, textile and laminate floor cover­ ings. 2005-2 DIN EN 685 (draft standard) Resilient, textile and laminate floor coverings. 2005-5 DIN EN 1 307 Textile floor coverings - Classification of pile carpets. 2005-5 DIN 51 1 30 Testing of floor coverings - Determination of the anti-slip properties. 2004-6 D I N 1 8202 Dimensional tolerances in building construc­ tion - buildings. 1 997-4 DIN 4 1 09-1 0 (draft standard) Sound insulation in build­ ings - Part 1 0: Proposals for improved sound insulation for housing. 2000-6 Surfaces and coatings DIN V 1 8550 Plastering/rendering and plasteringirender­ ing systems. 2005-4 DIN EN 998-1 Specification for mortar for masonry ­ Part 1 : Rendering and plastering mortar. 2003-9 DIN EN 459 Building lime. 2002-2 D I N EN 1 3279 Gypsum binders and gypsum plasters. 1 998-7 D I N 1 8558 Synthetic resin plasters. 1 985-1 DIN EN 971 -1 Paints and varnishes - Terms and definitions for coating materials - Part 1 : General terms. 1 996-9 DIN 1 8363 Contract procedures for building works Part C: General technical specifications for building works; Painting works. 2002- 1 2 DIN 55945 Paints and varnishes - Terms and definitions for coating materials. 1 999-7 DIN EN 1 062 Paints and varnishes - Coating materials and coating systems for exterior masonry and concrete. 2004-8 D I N EN ISO 1 2944 Paints and varnishes - Corrosion pro­ tection of steel structures by protective paint systems. 1 998-7 EN 1 3300 Paints and varnishes - Water-borne coating materials and coating systems for interior walls and ceilings. 2002-1 1 DIN EN ISO 1 2572 Building materials - Determination of water vapour transmission properties. 2001 -9 Maximum workin g place concentrations and biological tolerance values for substances. Deutsche Forschungs­ gesellschaft DFG, Weinheim DIN 8580 Manufacturing methods; classification. 2003-9 DIN 4 1 02 Fire behaviour of building materials and build­ ing components. 1 998-5

Part E

Appendix

Physical parameters of materials D I N 4 1 08 Thermal protection and energy economy in buildings. 2003-7 D I N EN 1 2524 Building materials and products - Hygro­ thermal properties - Tabulated design values. 2000-7 Eurocode 2 (EC2) D I N 4 1 02 Fire behaviour of building materials and build­ ing components. 1 998-5

272

D I N EN 1 3501 Fire classification of construction products and building elements. 2002-6 Hazardous substances Biocidal Products Directive (98/8/EC) Hazardous Substances Act TRGS 5 1 9 (technical rules for health and safety) : Asbestos Refurbishment Works Chemicals Prohibition Act 1 996 Formaldehyde Directive: D I Bt D irective 1 00 TRGS 905 List of carcinogenic, mutagenic or reprotoxic substances

Bibliography General Cowan, Henry J.; Smith, Peter: The Science and Technology of Building Materials, New York, 1 988 Deplazes, Andrea (ed . ) : Constructing Architecture. Materials. Processes. Structures. A Handbook, Basel! BostonlBerlin , 2005 Everett, Alan: Materials (Mitchell's Building Series), Harlow, 1 994 Federal Ministry of Transport, Building & Urban Develop­ ment (pu b . ) : ECOBIS 2000 - Ecological Building Materials I nformation System of the Federal Ministry of Transport, Building & Urban Development and the Bavarian Chamber of Architects, with the help of the Bavarian Ministry for Regional Development & Environ­ mental Issues, CD-ROM, Berl in, 2000 Herzog, Thomas et al.: Facade Construction Manual, MunichlBasel, 2004 Hiese, Wolfram; Backe, Hans: Baustoffkunde fUr Aus­ bildung und Praxis, Dusseldorf, 2001 ibk I nstitut fur das Bauen mit Kunststoffen e.v.: Bauen mit Kunststoffen , Berl in, 2002 Kaltenbach, Frank (ed . ) : Translucent Materials: Glass, Plastics, Metals, MunichlBasel, 2004 Lyons, Arthur: Materials for Architects and Builders: An Introduction, 2nd edition, London, 2004 Neumann, Dietrich; Weinbrenner, Ulrich: FricklKniill Bau­ konstruktionslehre 1 , StuttgartlLeipziglWiesbaden, 2002 Neumann, Dietrich; Weinbrenner, Ulrich: FricklKniill Bau­ konstruk1ionslehre 2, StuttgartlLeipziglWiesbaden, 2004 Sambeth, Burkhard (ed.) et a l . : Baustoffe und O kologie. Bewertungskriterien fUr Architekten und Bauherren, TubingenlBerlin, 1 996 Schmitz, Robert: Baustoffkunde fUr Praktiker, Duisburg, 2002 Schneider, Klaus-Jurgen (ed . ) : Bautabellen fUr Architek­ ten, Dusseldorf, 2001 Scholz, Wilhelm; Hiese, Wolfram: Baustoffkenntnis, Munich, 2003 Schulze Darup , Burkhard: Bauiikologie, Wiesbaden/ Berlin, 1 996 Schwarz, Jutta: O kologie im Bau. Entscheidungshilfen zur Beurteilung und Auswahl von Baumaterialien, Bern/StuttgartNienna, 1 998 Stark, Jochen; Wicht, Bernd: Geschichte der Baustoffe, Weimar, 1 995 Volland, Karlheinz: Einblicke in die Baustoffkunde fUr Architek1en, Dusseldorf, 1 999 Vollenschaar, Dieter; Wendehorst, Reinhard: Baustoff­ kunde, Hannover, 2004 Weidinger, Hans: Patina. Neue Asthetik in der zeit­ geniissischen Architektur, Munich, 2003 Wendehorst, Reinhard; Wetzell, Otto: Bautechnische Zahlentafeln, Stuttgart, 2002 Weston , Richard: Material, Form and Architecture, Stuttgart, 2003

Part A

Materials and architecture

The critical path to sustainable construction eco-bau (pub.): O kologisch Bauen - Merkblatter nach Baukostenplan (BKP) fUr Ausschreibungen, Bern, 2005 G ISBAU - Hazardous Substances I nformation System of the employers' liability insurance association for the building industry: WING IS, integrated into ECOBIS ­ Ecological Building Materials I nformation System, Berlin, 2000 Intep - Integrale Planung; Bayerische Hypo- & Vereins­ bank (pub.): Gesundes Buro - Leitfaden fUr die Realis­ ierung von nachhaltigen und gesunden Burogebauden, Munich, 2002 Intep - Integrale Planung et al. (pub.): Sanierung von Wohnungsbauten - Leitfaden zum ImmoPass fUr die nachhaltige Sanierung von Wohnbauten, Munich, 2001 Intep - Integrale Planung; ifib I nstitut fUr I ndustrielle Bau­ produk1ion: LuZie - Lebenszyklusbezogene Einbindung der Zielplanung und des Zielcontrolling in den Integ­ ralen Planungsprozess; research project within the scope of the EnSan development programme of the Federal Ministry of Industry & Employment, Munich! Karlsruhe, 2004 Intep - Integrale Planung et al. (pub . ) : SIA Documentation D 0 1 23 - Hochbaukonstruk1ionen nach iikologischen Gesichtspunkten, Zurich, 1 995 Intep I ntegrale Planung et al. (pub.): SIA Documentation D 0 1 52 - Instrumente fUr iikologisches Bauen im Ver­ gleich - Ein Leitfaden fur das Planungsteam, Zurich, 1 998 Koordinationsgruppe Nachhaltigkeit, Schweizer Inge­ nieur- & Architek1enverein (SIA) (pub.): SIA Documenta­ tion 0 0 1 64 - Kriterien fUr nachhaltige Bauten, Zurich, 2002 Marme/Seeberger: Der Primarenergiegehalt von Baustof­ fen; in: Bauphysik 5/1 982 & 6/1982 Ministry of Building & Regional Planning, on behalf of the Federal Office for Transport, Building & Housing (pub.): Leitfaden Nachhaltiges Bauen, Berlin, 2001 Schweizer Ingenieur- & Architek1enverein (SIA) (pub.): SIA Documentation 0200 - SNARC - Systematik zur Beurteilung der Nachhaltigkeit von Architekturprojekten fur den Bereich Umwelt, Zurich, 2004 Schweizer Ingenieur- & Architek1enverein (SIA) (pub.): SIA Recommendations 1 1 211 - Nachhaltiges Bauen Hochbau, Zurich, 2005 Schweizer Ingenieur- & Architektenverein (SIA) (pub . ) : SIA Recommendations 493 - Deklaration iikologischer Merkmale von Bauproduk1en , Zurich, 1 997 Schweizer Ingenieur- & Architek1enverein (SIA) (pub.): SIA Documentation D 093 - Deklaration iikologischer Merkmale von Bauproduk1en nach SIA 493 - Erlaute­ rung und I nterpretation, Zurich, 1 997 Swiss Federal Office of Energy (BFE) and Koordinations­ gruppe O kologisch Bauen (kiib) (pub.): Konzept elek­ tronischer Bauteilkatalog, Bern, 2003 Zwiener, Gerd et al.: O kologisches Baustoff-Lexikon Daten, Sachzusammenhange, Regelwerke, Heidelberg, 2003

Building awards: ECO-BAU: MINERGIE: LEED: BREEAM: TOTAL QUALITY:

www.eco-bau.ch www.minergie.ch www. usgbc.org www.breeam.org www.argetq.at

Computer tools: Catalogue of components: LEGEP: OGIP: VITRUVIUS: SNARC: ECOBIS: WINGIS:

www. bauteilkatalog.ch www.sirados.de/c.phplProduk1e/ Legoe-Bausoftwarellegep.rsys www.the-software.de/Ogipl .html www.vitruvius.ch www.eco-devis.ch www.byak.de/ak1uelles/aktuelles_ digpub_ecobis.html www.gisbau.de

Bibl iography

Reference works: Sustainable building guidelines: SIA D0123: BKP data sheets: ECO-DEVIS:

www. bbr.bund.de/bauwesenl nachhaltigbauen/download/ leitfaden.pdf www.sia.ch www.eco-devis.ch www.eco-devis.ch

The development of innovative materials Arch+ 1 72, 2004 Lefteri, Chris: Plastic: Materials for Inspirational Design, Ludwigsburg, 2002 Stattmann, Nicola: Hand book of Material Technologies, Ludwigsburg, 2003 Stattmann, Nicola: Ultra Light - Super Strong: A New Generation of Design Materials, BaseVEoston/Berlin, 2003 Zijlstra, Eis: Future materials for architecture & design, Materia, 2002

Part B

Properties of building materials

Stone Bradley, Frederick: Natural Stone: A Guide to Selection/ Studio Marmo, New York, 1 998 Bruckner, Heinrich; Schneider, Ulrich: Naturbaustofte, Dusseldorf, 1 998 Dernie, David: New Stone Architecture, London, 2003 Donaldson, Barry (ed.): New Stone Technology, Design, and Construction for Exterior Wall Systems, Philadel­ phia, 1 988 Eggericx, Laure: Naturstein in Belgien; in: Detail 1 1 /1 999, p. 1 24 1 ft. Germann, Albrecht (ed . ) : Naturstein-Lexikon: Gesteins­ kunde und Handelsnamen; Natursteingewinnung; Natursteinverarbeitung; Naturstein im Innen- und Aussenbereich; Kunstgeschichte und Architektur, Munich, 2003 Hugues, Theodor et al.: Dressed Stone, MunichiBasel, 2005 Mackler, Christoph (ed . ) : Material Stone: Constructions and Technologies for Contemporary Architecture, BasellBerlin/Boston, 2004 Muller, Friedrich: Gesteinskunde: Lehrbuch und Nach­ schlagewerk uber Gesteine fur Hochbau, Innenarchitektur, Kunst und Restaurierung, Ulm, 2001 Schittich, Christian: Naturstein - ein Baustoft fUr's nachste Jahrhundert?; in: Detail 06/1 999, p. 942ft. Schwarz, Rudolf: Bauen mit Naturstein; in: Detail 6/1 999, p. 1 02 1 ft. Wanetschek, Margret and Horst (ed . ) : Naturstein und Architektur: Fassaden, I nnenraume, Aussenanlagen, Steintechnik, Munich, 2000 Weber, Johann: Oberflachenbearbeitung von Naturstein; in: Detail 1 1 /2003, p. 1 304ft. Weber, Rainer; Hill, Detlev: Naturstei n fur Anwender: beurteilen - verkaufen - verlegen, Ulm, 2002 Winkler, Erhard M.: Stone in Architecture : Properties, Durability, BerlinlNew York, 2002 Loam Bruckner, Heinrich; Schneider, Ulrich: Naturbaustofte, Dusseldorf, 1 998 Chesi, Gert: Einfaches Bauen mit Lehm - Wohnhauser im Sahel; in: Detail 01/1 998, p . 6ft. Dachverband Lehm e.v. (pu b . ) : Lehmbau Regeln: Begrifte, Baustofte, Bauteile, BraunschweigIWiesbaden, 2002 Die Wille gGmbH: Moderner Lehmbau 2003: Nachhalti­ ger Wohnungsbau - Zukunft 6kologisches Bauen, Stuttgart, 2003 Kapfinger, Otto; Rauch, Martin: Rammed Earth, Lehm und Architektur, Terra cruda, BasellBostonlBerlin, 2001 Keefe, Laurence: Earth Building: Methods and Materials, Repair and Conservation , London, 2005 Minke, Gernot: Building with Earth: Design and Technolo­ gy of a Sustainable Architecture, BasellBostonlBerlin, 2006 Minke, Gernot: Earth Construction Handbook, South­ hampton, 2000 Rauch, Martin: Konstruieren mit Stampflehm; in: Detail 06/2003, p. 650ft. Schneider, Ulrich et al.: Lehmbau fUr Architekten und

I ngenieure: Konstruktion, Baustofte undBauverfahren, Prufungen und Normen, Rechenwerte, Dusseldorf, 1 996 Volhard, Franz: Mit Lehm bauen; in: Detail 01/1 998 p. 77ft. Ziegert, Christof: In Balance - Das Feuchtesorptions­ verm6gen von Lehmbaustoften; in: db 0212003, p. 73ft. zur Nieden, Gunter; Ziegert, Christof: Neue Lehm-Hauser international: Projektbeispiele, Konstruktionen, Details, Berl in, 2002 Ceramic materials Bender, Wi lli: Lexikon der Ziegel: Vom Aaldeckenziegel bis zum Zwischenwandziegel in Wort und Bild, WiesbadenlBerlin, 1 995 Hugues, Theodor et al.: Building with Large Clay Blocks, MunichlBasel, 2003 Irmschler, Hans-J6rg et al. (ed . ) : Mauerwerk-Kalender, Berlin, 2004 Jager, Wolfram; Schneider, Klaus (ed . ) : Mauerwerksbau aktuell. Praxishandbuch 2003, Berlin, 2003 Pfeifer, Gunter et al.: Masonry Construction Manual, Munich/Basel, 2001 Schunck, Eberhardt et al.: Roof Construction Manual, Munich/Basel, 2003 Building materials with mineral binders Becker, Klausjurgen et a l . : Trockenbauatlas. Grundlagen, Einsatzbereiche, Konstruktionen, Details, Cologne, 2004 Bennett, David: Exploring Concrete Architecture: Tone Texture Form, BasellBostonlBerlin, 2001 Bennett, David: The Art of Precast Concrete: Colour, Texture, Expression, Basel/BostonlBerlin, 2005 Cohen, Jean-Louis: Liquid Stone: New Architecture in Concrete, BasellBostonlBerlin, 2006 Croft, Catherine: Concrete Architecture, Layton, 2004 Fr6hlich, Burkhard (ed . ) : Concrete Architecture: Design and Construction, BasellBoston/Berl in, 2002 Grubl, Peter: Beton. Arten , Herstellung und Eigen­ schaften, Berl in, 2001 Harig, Siegfried et al.: Technologie der Baustofte. Hand­ buch fUr Studium und Praxis, Heidelberg, 2003 Kind-Barkauskas, Friedbert et a l . : Concrete Construction Manual, MunichiBasel, 2002 K6nig, Gert: Faserbeton, Berlin, 2002 Krippner, Roland: Holzleichtbeton; in: DBZ 1 212002 Pfeifer, Gunter et a l . : Exposed Concrete: Technology and Design, BasellBostonlBerl in, 2005 Bituminous materials Bitumen Industry Working Group, Arbit (pub.): Die neuen Bitumenspezifikationen gemass DIN 1 2591 , Hamburg, 1 999 bga Beratungsstelle fur Gussasphaltanwendungen e.V. bga Beratungsstelle fUr Gussasphaltanwendungen e.V. (pub.): Asphaltkalender 2001 . Bitumenwerkstofte und ihre Anwendungen, Berlin, 2001 Eiserloh, Hans Peter: Handbuch Dachabdichtung. Auf­ bau, Werkstofte, Verarbeitung, Details, Cologne, 2002 Glet, Walther: Aspekte zu Emissionen aus Bitumen, Asphalt und alten Strassenbaustoften . Gefahrstofte Reinhaltun9 der Luft, SI. Augustin, No. 1 0/1 998 von Busso, Hans-Busso et al.: Atlas Flache Dacher. Nutzbare Flachen, MunichiBasel, 1 994 Wetzel , Waiter; Collin, Gerd: Asphalt, Bitumen, Teer ­ ihre Bedeutung in der Kultur- und Technikgeschichte; in: Erd61, Erdgas, Kohle, Oct 1 999, p . 488ft. Zentralverband des Deutschen Dachdeckerhandwerks Fachverband Dach-, Wand- und Abdichtungstechnik e.v. (pub.): Richtlinien fur die Planung und AusfUhrung von Dachern mit Abdichtungen. Flachdachrichtlinien, Cologne, 2001 Wood and wood-based products Arbeitsgemeinschaft Holz e.v. et al.. Holzbau Handbuch, Dusseldorf, 2000 Arbeitsgemeinschaft Holz e.v. in conjunction with HOLZ­ ABSATZFONDS: Holz, Rohstoft der Zukunft: nachhaltig verfugbar und umweltgerecht, Munich, 2001 Arbeitsgemeinschaft Holz e.v. in conjunction with HOLZ­ ABSATZFONDS: Konstruktive Holzwerkstofte, Dussel­ dorf, 1 997

Arbeitsgemeinschaft Holz e.V. i n conjunction with HOLZ­ ABSATZFONDS: Konstruktive Vollholzprodukte, Munich, 2000 Arbeitsgemeinschaft Holz e.V. in conjunction with HOLZ­ ABSATZFONDS: Nachhaltiges Bauen mit Holz, Munich, 2002 Cerliani, Christian; Baggenstos, Thomas: Sperrholz­ architektur, Dietikon, 2000 DGH I nnovations- und Service GmbH: Einheimische Nutzh61zer und ihre Verwendung, Bonn, 2000 Gabriel, Andreas: Holzbau heute; in: Detail 01/2000, p. 20 Henrichsen, Christoph: Japan - Culture of Wood: Build­ ings, Objects, Techniques, BasellBostonlBerlin, 2004 Herzog, Thomas et al.: Timber Construction Manual, MunichiBasel, 2003 HOLZABSATZFONDS: D I N 4074: Building timber for wood building components; quality conditions for build­ ing logs, Bonn, 2004 Hugues, Theodor et al.: Timber Construction, Munich! Basel, 2004 Kaufmann, Hermann: Holz - ein universeller Baustoft; in: Detail 0 1 --D2I2004, p. 1 2 ft. Meier, Ulrich: Moderne Holzhauser: Systeme, Kombina­ tionen, Beispiele, Karlsruhe, 2004 Muller, Christian: Laminated Timber Construction, Basel/ Boston/Berlin, 2000 Radovic, Borimir: Holzwerkstofte und deren Einsatz­ gebiete im Bauwesen; in: Detail 0 1 /2000, p. 91 ft. Sandoz, Jean-Luc; Schmitt, Jan-Erik: Vom Molekul zum Bauwerk; in: Detail 01 --D2I2004, p . 76 Zwerger, Klaus: Wood and Wood Joints, BasellBostonl Berlin, 1 997 Metal Federal Ministry of Transport, Building & Urban Develop­ ment: Ecobis 2000, Ecological Building Materials Infor­ mation System, Bonn/Berlin, 2000 Fr6hlich, Burkhard; Schulenburg, Sonja (eds.): Metal Architecture: Design and Construction, BasellBoston/ Berlin, 2003 Hullmann, Heinz: Materialexperimente - I nnovation bei Konstruktion und Gestaltung; in: DBZ 1 212002, pp. 26-29 Initiative Zink: Die Bedeutung von Zink, Dusseldorf LeCuyer, Annette: Steel and Beyond: New Strategies for Metals in Architecture, Basel/BostonlBerlin, 2003 Schulitz, Helmut C. et al.: Steel Construction Manual, MunichlBasel, 2000 Schunck, Eberhardt et al.: Roof Construction Manual, MunichlBasel, 2003 Verein Deutscher Eisenhutteleute: SEW 3 1 0. Physika­ lische Eigenschaften von Stahlen, Dusseldorf, 1 992 Wilquin, Hugues: Aluminium Architecture: Construction and Details, BasellBostonlBerlin, 2001 Glass Archilles, Andreas et a l . : Glasklar, Munich, 2003 Auer, Thomas: Glasvisionen - zur Zukunft eines Baustofts; in: DBZ 1 1 /2004, p. 56-63 Grimm, Friedrich: Energieeftizientes Bauen mit Glas, Munich, 2004 Knaack, Ulrich: Konstruktiver Glasbau, Cologne, 1 998 Kresing, Rainer: Innen ist Aussen ist I n nen - bauen mit Glas; in: DBZ 1 0/2002, pp . 30-33 Krewinkel, Heinz W.: Glass Buildings: Material, Structure and Detail, Basel/Boston/Berlin, 1 998 Lefteri, Chris: Glass: Materials for Inspirational Design, Ludwigsburg, 2002 Loughran, Patrick: Falling Glass: Problems and Solutions in Contemporary Architecture, BasellBostonlBerlin, 2003 Nijsse, Rob: Glass in Structures, BasellBostonlBerlin, 2003 Petzold Armin et a l . : Der Baustoft Glas. Grundlagen, Eigenschaften, Erzeugnisse, Glasbauelemente, Anwendungen, Schondorf, 1 990 Schittich, Christian et a l . : Glass Construction Manual, MunichiBasel, 1 999 Schneider, U lrich et a l . : AluminiumlGlas. Baustofte und ihre Anwendungen, ViennaINew York, 2002 Scholze, Hors!: Glas, Natur, Struktur und Eigenschaften, Berlin 1 998

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Weischede, Dietger; Fahlbusch, Marc: Seminar Proceed­ ings for Wahlfach Glas + Leichtbau, SS 2003, Darm­ stadt TU, 2003 Synthetic materials Burkhardt, Berthold et al : Bausysteme mit Kunststoffen, Stuttgart, 1 974 Dehn, Frank et al.: Konstruktionswerkstoffe im Bauwesen, Berlin, 2003 Ehrenstein, Gottfried Wilhelm et al.: Praxis der ther­ mischen Analyse von Kunststoffen , Munich, 2003 Hellerich, Waiter et al.: Werkstoff-FOhrer Kunststoffe. Eigenschaften, PrOfungen, Kennwerte, MunichNienna, 2004 Saechtling, HansjOrgen (ed.): Bauen mit Kunststoffen . Baustoffkunde und Baupraxis. Bauarten, Bauwerke, Baubestimmungen, Normen, Richtlinien, Munich, 1 973 Schwarz, Otto; Ebeling, Friedrich-Wolfhard: Kunst­ stoffkunde. Aufbau, Eigenschaften, Verarbeitung, Anwendung der Thermoplaste, Duroplaste und Elastomere, WOrzburg, 2005 Schwarz, Otto et al.: Kunststoffverarbeitung, WOrzburg, 2003 Life cycle assessments Arbeitsgemeinschaft umweltvertragliches Bauprodukt eV.: Allgemeiner Leitfaden - Entwurf Fassung 5, Kbnigswinter, 2004 Federal Ministry for the Environment, Nature Conservation & Nuclear Safety; Federation of German Industries: Umweltinformationen fOr Produkte und Dienstleistungen, BonnlBerlin, 2003 Federal Environmental Agency (UBA): Handreichung zur Bewertun g in O kobilanzen, BonnlBerlin, 2000

Part C

Applications of building materials

The building envelope (facade) Arbeitsgemeinschaft Holz e.V. in conjunction with HOLZ­ ABSATZFONDS: Aussenbekleidungen mit Holzwerk­ stoffplatten, Munich, 2001 Archilles, Andreas et al.: Glasklar, Munich, 2003 Bauberatung Zement: Schalung fOr Beton Bauberatung Zement: Sichtmauerwerk aus Beton (Normalbeton) Baus, Ursula; Siegele Klaus: Holzfassaden: Konstruktion, Gestaltung, Beispiele, Stuttgart, 2000 Behling, Sophia; Behling, Stefan: Glass - Structure and Technology in Architecture, Munich/london , 2000 Dbring, Wolfgang et al.: Fassaden: Architektur und Kon­ struktion mit Betonfertigteilen , DOsseldorf, 2000 Dyckerhoff Weiss GmbH: Ausschreibungshinweise fOr farbigen Sichtbeton, Wiesbaden, 2003 Eternit AG: Fassaden mit Faserzement, Heidelberg Fachverband Baustoffe und Bauteile fOr vorgehangte hin­ terlOftete Fassaden e.V.: FVHF - Fokus, No. 24: Gestal­ tungsqualitaten von vorgehangten hinterlOfteten Fas­ sad en (VHF), Berlin German Copper Institute: Dachdeckung und Aussen­ wandbekleidung mit Kupfer, DOsseldorf, 2002 Grimm, Friedrich: Energieeffizientes Bauen mit Glas, Munich, 2004 Kucker, Wilhelm et al.: Fassade - Gesicht, Haut oder HOlle; in: Der Architekt 05/1 998, pp. 261 -303 Neue Anziehungskrafte: Bauen und Bekleiden; in: Bau­ meister 07/1 998, p. 42ff. Moegenburg, Gert: Vorgehangte HinterlOftete Fassaden; in: Deutsches Architektenblatt 1 1 /2002, p . 50ff. Pfeifer, GOnter et a l . : Masonry Construction Manual, Munich/Basel, 2001 Schafer, Stefan : Fassadenoberflachen aus metallischen Werkstoffen; in: Detail 01 -0212003, p . 90ff. Schittich, Christian: Die zeitgemasse Fassade: Verpackung od er reagierende Haut; in: Detail 07/1998, p. 1 1 42ff. Schittich, Christian (ed . ) : Building Skins, BasellBostonl Berlin, 2001 Schittich, Christian: Zwischen modischer Verpackung und reagierender Haut: Gestalterische Tendenzen kultureller Fassaden; in: Detail 07-08/2003, p. 756

274

The building envelope (roof) bga Beratungsstelle fOr Gussasphaltanwendungen e V (pub.): Asphaltkalender 2001 . Bitumenwerkstoffe und ihre Anwendungen, Berlin, 2001 Bobran, Hans et al.: Flachdachaufbauten mit Dichtungs­ bahnen - Die Suche nach dem sicheren Dach; in: Detail 07-08/2002, p . 954ff. Eiserloh, Hans Peter: Handbuch Dachabdichtung. Aufbau, Werkstoffe, Verarbeitung, Details, Cologne, 2002 GrOn, Ingo: Das Foliendach; in: Detail 03/1 990, p. 305ff. GrOn, Ingo: Flachdach heute; in: Detail 03/1 990, p. 246ff. Koch, Klaus-Michael: Memrane Structures: The Fifth Building Material, Munich/BerlinILondon/New York, 2004 Moritz, Karsten : Membrane materials in structural engi­ neering; in: Kaltenbach, Frank (ed . ) : Translucent Materials, Munich/Basel, 2003, p. 58-69 Schock, Hans-Joachim: Soft Shells: Design and Technol­ ogy of Tensile Architecture, BasellBostonIBerlin, 1 997 Schunck, Eberhardt et al.: Roof Construction Manual, MunichlBasel, 2003 Sterly, Hans-JOrgen et al.: Details rund um das Ziegel­ dach, Cologne, 2003 von Busso, Hans-Busso et al.: Atlas Flache Dacher. Nutzbare Flachen, Munich/Basel, 1 994 Zentralverband des Deutschen Dachdeckerhandwerks Fachverband Dach-, Wand- und Abdichtungstechnik eV (pub.): Deutsches Dachdeckerhandwerk: Regeln fOr Dachdeckungen, Cologne, 1 997 Zentralverband des Deutschen Dachdeckerhandwerks Fachverband Dach-, Wand- und Abdichtungstechnik eV (pub.): Richtlinien fOr die Planung und AusfOhrung von Dachern mit Abdichtungen. Flachdachrichtlinien, Cologne, 2001 Zink, Waiter (ed . ) : Vom Flachdach zum Dachgarten. Moderne Flachdachtechnik, Stuttgart, 1 976 Insulating and sealing Bayerisches Zentrum fOr Angewandte Energieforschung eV (ZAE Bavaria): Schaltbare Dammung zur Solar­ energienutzung Bobran-Wittfoht, Ingrid; Schlauch, Dirk: Dammstoffe fOr den baulichen Warmeschutz - (k)einer fOr alle Falle; in: Detail 07/2001 , p . 1 290ff. Bremen Energy I nstitute: Innovative Dammstoffe im Bau­ wesen, Bremen, 2005 Fachverband Transparente Warmedammung e V : Transparente Warmedammung, Gundelfingen, 2005 G D I - Gesamtverband Dammstoffindustrie; Steimle, Petra: Energieeffizientes Bauen - Warmedammung ist der erste Schritt, Frankfurt, 2004 Mbtzl, Hildegund; Zelger, Thomas: O kologie der Damm­ stoffe, ViennaINew York, 2000 Reyer, Eckhard et al.: Kompendium der Dammstoffe, Stuttgart, 2002 Schwab, Hubert et a l . : Vakuumisolationspaneele In: Detail 07/2001 , p . 1 301 Simmler, Hans; Wakili, Ghazi: Vakuumdammung im Bau­ bereich, Duebendorf, 2005 Baden-WOrttemberg Ministry of the Economy: Damm­ stoffe im Hochbau, Stuttgart, 2003 Building services Daniels, Klaus: Advanced Building Systems: A Technical Guide for Architects and Engineers, Basel , 2003 Pistohl, Wolfram: Handbuch der Gebaudetechnik. Grundlagen und Beispiele, vol. 1 , DOsseldorf, 2002 Pistohl, Wolfram: Handbuch der Gebaudetechnik. Grundlagen und Beispiele, vol. 2, DOsseldorf, 2000 Volger, Karl; Laasch, Eberhard: Haustechnik. Grundlagen. Planung. AusfOhrung, Leipzig, 1 999 Wellpott, Edwin: Technischer Ausbau von Gebauden, StuttgartlBerlinlCologne, 2000 Walls Albin, ROdiger: Grundlagen des Mbbel- und Innenaus­ baus: Werkstoffe - Konstruktion, Verarbeitung von Voll­ holz und Platten, Beschichtung, Oberflachenbehand­ lung, MbbelprOfung, Leinfelden-Echterdingen, 1 991 Dbrries, Cornelia; Patena, Andrea: Raumkunst, Berlin, 2004 Marschall, Verena: Wohnen mit Glas, Munich, 2003 Myerson Jeremy; Hudson, Jennifer: Innenraume, Munich, 2000

Nutsch, Wolfgang: Handbuch der Konstruktion: I nnenausbau, StuttgartlMunich, 2000 Peukert, Martin: Gebaudeausstattung. Systeme, Produkte, Materialien, Munich, 2004 Pfeifer, GOnter et al.: Masonry Construction Manual, Munich/Basel , 2001 Pracht, Klaus: Mbbel und Innenausbau, TObingen, 1 996 Rose, Wulf-Dietrich: Wohngifte - Handbuch fOr gesundes Bauen und Einrichten, Cologne, 1 994 Schittich, Christian (ed . ) : I nterior Spaces: Space, Light, Material, BasellBostonlBerlin, 2002 Schricker, Rudolf et a l . : Innenarchitektur in Deutschland, Leinfelden-Echterdingen, 2002 Schulz, Peter: Handbuch fOr den I nnenausbau, Stuttgart, 2004 Steinhbfel, Otto: Werkstoffe und Verarbeitung im I nnenausbau, Stuttgart, 1 965 van Onna, Edwin: Material world - innovative structures and finishes for interiors, BasellBostonlBerlin, 2002 Weber, Helmut; Hullmann, Heinz: Porenbeton-Handbuch. Planen und Bauen mit System, Wiesbaden, 2002 Wilhide, Elizabeth: Holz, Glas und Co., Stuttgart, 2002 Intermediate floors Herzog, Thomas et al : Timber Construction Manual, MunichlBasel , 2004 Kind-Barkauskas, Friedbert et a l . : Concrete Construction Manual, MunichlDOsseldorf, 2002 Kroyss, Josef; Bammer, Alois: biologisch, natOrlich bauen - ein Ratgeber biologischer Baustoffe, Stuttgart, 2000 Peukert, Martin: Gebaudeausstattung. Systeme, Produkte, Materialien, Munich, 2004 Weber, Helmut; Hullmann, Heinz: Porenbeton-Handbuch, Planen und Bauen mit System, Wiesbaden, 2002 Floors Arbeitsgemeinschaft Holz e.V. : Holzbau Handbuch Reihe 6, Teil 4 , Folge 2, Parkett-Planungsgrundlagen, DOsseldorf, 2001 BD lA (pub.) Stratenwerth-Nelte, Anna: Innenarchitekten, Wiesbaden, 2000 Bobran, Hans; Bobran-Wittfoht, Ingrid: Handbuch der Bauphysik, Braunschweig, 1 995 Bundesverband Flachenheizungen e V : Richtlinie zur Herstellung dOnnschichtiger beheizter Verbundkon­ struktionen in Wohnbestand, Hagen, 2004 Hill, Detlev: Naturstein im Innenausbau, Gestaltung und AusfOhrung, Cologne, 2003 Kroyss, Josef; Bammer, August: biologisch natOrlich Bauen, StuttgartlLeipzig, 2000 Waltjen, Tobias (ed . ) ; Mbtzl, Hildegund et al.: O kologi­ scher Bauteilkatalog. Bewertete gangige Konstruk­ tionen, Vienna/New York, 1 999 Wild, Uwe: Fliessestrich aus Zement; in: Deutsches Architektenblatt 1 1 /2004, p. 69ff. Wilhide, Elisabeth: Flooring: The Essential Source Book for Planning, Selecting and Restoring Floors, New York, 2005 Surfaces and coatings Bbttcher, Peter: I nformationsdienst Holz. Anstriche fOr Holz und Holzwerkstoffe im Aussenbereich, DOsseldorf, 1 999 Dettmering, Tanja: Putze in Bausanierung und Denkmal­ pflege, Berlin, 2001 Engelfried, Robert: Schiiden an polymeren Beschichtun­ gen, Stuttgart, 2001 , vol. 26 Frbssel, Frank: Handbuch Putz und Stuck. Herstellung, Beschichtung und Sanierung fOr Neu- und Altbau, Munich, 2003 Frbssel, Frank: Lexikon der Putz- und Stucktechnik, Stuttgart, 1 999 Hantschke, Bernhard; Hantschke, Christian: Lacke und Farben am Bau. Erstanstriche und Werterhaltung. Eine EinfOhrung fOr Maler, Architekten, Gutachter, StuttgartlLeipzig, 1 998 Huber, Marianne: Farbe, ein vielseitiger Baustoff; in: archithese 04/1 998, p. 29 KOppers, Harald: Color: Origin, Systems, Uses, London, 1 973 Nemcsics, Antal: Colour Dynamics: Environmental Colour Design, Budapest, 1 993

Picture credits

Reichel, Alexander et al.: Plaster, Render, Paint and Coat­ ings, Munich/Basel, 2004 Ross, Hartmut; Stahl, Friedemann: Praxis-Handbuch Putz. Stoffe, Verarbeitung, Schadensvermeidung, Cologne, 2003 Rusam, Hors!: Anstriche als Beschichtungen fUr minera­ lische Untergrunde: Eigenschaften und fachgerechte Aufbringung, Renningen, 2002 Rusam, Hors!: Anstriche und Beschichtungen im Bau­ wesen. Eigenschaften, Untergrunde, Anwendung, Stutt­ gart, 2004 Sch6nburg, Kurt: Beschichtungstechniken heute. Wirtschaftliche Faktoren, Beschichtungstrager, Putz­ gestaltung, Anstrichtechniken, Lackierungen, Korro­ sionsschutz, Holzschutz, Berlin, 2005 Munich TU, Institute of Building Materials & Building Design: Farbe; in: db 0312003 Wettstein, Stefanie: oas Recht auf Farbe - der Farbe ihr Recht! Zur Geschichte eines billigen Baustoffs; in: archithese 04/1 998, p. 26ff.

Picture credits The authors and publishers would like to express their sincere gratitude to all those who have assisted in the production of this book, be it through providing photos or artwork or granting permission to reproduce their docu­ ments or providing other information. All the drawings in this book were specially commissioned. Photographs not specifically credited were taken by the architects or are works photographs or were supplied from the archives of the magazine DETAIL. Despite intensive endeavours we were unable to establish copyright ownership in just a few cases; however, copyright is assured. Please notify us accordingly in such instances. The numbers refer to the figures.

Part A Materials and architecture A

Manfred Hegger, Kassel (D)

The surface in contemporary architecture A 1 .1 Christian Schittich, Munich (D) A 1 .2 Georges Fessy, Paris (F) Ralph Ri«!Jter/Architekfurphoto, ousseldorf (D) A 1 .3 A 1 .4 Shigeo Ogawa, Tokyo (J) A 1 .5-6 Daniel Malhao, Lisbon (P) A 1 .7 Christian Richters, Munster (D) Richard Glover/view, London (GB) A 1 .8 Margherita Spiluttini, Vienna (A) A 1 .9 The architect as building materials scout NASA, Washington DC (USA) A 2.1 Cabot International GmbH, Zug (CH) A 2.2 A 2.3-4 Jurgen Mayer H., Berlin (D) A 2.5 oaria ScagolialStijn Brakkee, Rotterdam (NL) A 2.6--7 Maurice Nio, Rotterdam (NL) OMA, Rotterdam (NL) A 2.8 Phil Meech/OMA, Rotterdam (NL) A 2.9 A.2 . 1 0 Christiane Sauer, Berlin (D) Phil Meech/OMA, Rotterdam (NL) A 2.1 1 The critical path to sustainable construction A 3.2-4 Ludwig Steiger, Munich (D) Criteria for the selection of building materials Royalty-Free/Corbis, ousseldorf (D) A 4.3 A 4.4 Mattieu Paley/Corbis, ousseldorf (D) The development of innovative materials A 5.9-12 BASF AG, Ludwigshafen

Touching the senses - materials and haptics in the design process A 6. 1 -3 frog design europe GmbH, Herrenberg (D) Apollinaris & Schweppes GmbH, Hamburg (D) A 6.4 A 6.5 frog design europe GmbH, Herrenberg (D) Apple Computer, Inc. A 6.6 A 6.7-9 frog design europe GmbH, Herrenberg (D) A 6. 1 0 Allianz Arena GmbH, Munich (D)

Part B Properties of building materials B

Manfred Hegger, Kassel (D)

Stone B 1 .1 B B B B B B B

1 .2 1 .3 1 .4 1 .5 1 .6 1 .7 1 .9

Avenue Images/Index StocklThomas Winz, Hamburg (D) Karlheinz Oster, Mettmann (D) Werner Lang, Munich (D) Paul Raftery/view/artur, Cologne (D) Royalty-Free/Corbis (D) Richard Weston, Cardiff (GB) oavid oernie, Cambridge (GB) Jens Lindhe, Copenhagen (OK)

Loam James McGoon, Portland (USA) B 2. 1 B 2.2-3 Mean drying shrinkage of building loams accord­ ing to former loam building standard DIN 1 8952-2 ILEK Stuttgart University (D) B 2.4 B 2.5 Markus Tretter, Lindau (D) B 2.6 Oliver, Paul: Dwellings, London, 2003, p . 96 Richard Weston, Cardiff (GB) B 2.7 Bruno Klomfar, Vienna (A) B 2.9 B 2 . 1 0a Claytec e.K., Viersen-Boisheim (D) B 2.1 Oc Andreas Gabriel, Munich (D) B 2.1 Od-f Franz Volhard, oarmstadt (D) Ceramic materials B 3.1 Keld Helmer-Petersen, Copenhagen ( O K ) . from: Weston, Richard: Material, Form and Architectu­ re, Stuttgart, 2003, p. 228 B 3.2 Vicente del Amo, Montevideo (ROU) B 3.3 Manfred Hegger, oarmstadt (D) Siegfried Layda, Wiesbaden, from: Buderath, B 3.4 Bernhard: Peter Behrens Umbautes Licht, Munich, 1 g90, p. 30 Petersen Tegl Egernsund AlS, Broager (OK) B 3.5 B 3.7-8 Wienerberger Ziegelindustrie GmbH, Hannover (D) Girnghuber GmbH, Marklkofen (D) B 3.9 Klaus Kinold, Munich (D) B 3. 1 1 B 3. 1 3 Advertise/Fotofinder Manuel Zoller, Munich (D) B 3. 1 4 B 3. 1 5 Hans-Georg Esch, Hennef-Sieg (D) B 3. 1 7 Rob t' Hart, Rotterdam (NL) B 3. 1 8 Jari Jetsonen, Helsinki (FIN) Building materials with mineral binders Roland Halbe/artur, Cologne (D) B 4.1 B 4.2 Araldo de LucalCorbis, ousseldorf (D) B 4.3 Michel oenance/Archipress/artur, Cologne (D) B 4.5 Hisao Suzuki, Barcelona (E) B 4.7 Klaus Frahmlartur, Cologne (D) B 4.8 Paul Raftery/view/artur, Cologne (D) Felix Borkenau/artur, Cologne (D) B 4.12 B 4 . 1 4 Werner Huthmacher/artur, Cologne (D) B 4 . 1 5 Hannes Henz, Zurich (CH) B 4 . 1 7 Steffi Lenzen, Munich (D) B 4 . 1 8a-b ARGE Holz, ousseldorf (D) B 4 . 1 8c Friedemann Zeitier, Penzberg (D) B 4 . 1 8d Knauf AG, I phofen (D) B 4.21 Patrik Engquist, Stockholm (S) B 4.22 Margherita Spiluttini, Vienna (A) Bituminous materials B 5.1 NYNAS Bitumen, Zaventem (B) AKG Images, Berlin (D) B 5.4 Stuttgarter Nachrichten archives/Horner (D) B 5.5 B 5.7 Imperbel Group, Lot (B) Initiative Pro Keller e.V., Friedberg (D) B 5.9 B 5 . 1 0 A. J. McCormack & Son, Culcheth (GB)

Wood and wood-based products Moreno Maggi, Rom (I) B 6.1 B 6.2 U . Pfistermeister, Artelshofen (D) KlammeVmediacolors B 6.3 Adam WoolfittlCorbis, ousseldorf (D) B 6.6 P. Sessner, Munich (D) B 6.7 B 6.8 Eduard Hueber, New York (USA) B 6.9-1 0 Dr. Grosser, Timber Research Unit, Munich TU (D) B 6. 1 2 Hans-Joachim Heyer, Photography Workshop, Stuttgart University (D) B 6 . 1 4a Holzabsatzfonds, Bonn (D) B 6.18 Holzabsatzfonds, Bonn (D) B 6.2 1 -22 Anne Bousema, Rotterdam (NL) Metal B 7.1 B 7.3

J6rg Hempeilartur, Cologne (D) SchapowalowlBildagentur Huber/ Fantuz Olimpio PictureNeVCorbis, ousseldorf (D) B 7.4 B 7.5 artur/oieter Leistner, Mainz (D) B 7.7a Alcan Sing en GmbH, Singen (D) B 7.7b Heike Werner, Munich (D) Mevaco GmbH, Schlierbach (D) B 7.7c B 7.7d-e Heike Werner, Munich (D) B 7.7f V. Carl Schr6ter, Hamburg (D) B 7.7g-h Gebr. Kufferath GmbH & Co. KG, ouren (D) B 7.7i Stappert Spezial-Stahl Handel GmbH, oussel­ dorf (D) B 7.7j Reynaers GmbH Aluminium Systems, Gladbeck B 7.7k Christian Schittich, Munich (D) Hansa Metallwerke AG, Stuttgart (D) B 7.71 BettmannlCorbis, ousseldorf (D) B 7.9 Avenue Images/Index Stock/Mark oyball B 7.1 1 B 7 . 1 2 Jochen Helle/artur, Cologne (D) oavid Franck, Ostfildern (D) B 7.13 B 7 . 1 4 Sandro Vannini/Corbis, ousseldorf (D) B 7 . 1 5 Jochen Helle/artur, Cologne (D) B 7 . 1 6 Wolfram Janzer/artur, Cologne (D) B 7 . 1 8 James Leynse/Corbis, ousseldorf (D) B 7.18 Roland Halbe/artur, Cologne (D) Glass B 8. 1 B 8.4 B 8.5 B 8. 7 B 8.8 B 8. 1 1 B 8. 1 3 B 8. 1 5

Marquardt Architekfen, Stuttgart (D) oennis Gilbertlview/artur, Cologne (D) Richard Weston, Cardiff (GB) Christian Kandzia, Stuttgart (D) Richard Weston, Cardiff (GB) oennis Gilbertlview/artur, Cologne (D) Owen Frankenlcorbis, ousseldorf (D) Werner Sobek Ingenieure, Stuttgart (D)

Synthetic materials Frank Kaltenbach, Munich (D) B 9. 1 Zanotta spa, novas Milanese B 9.2 from: Dieter Bogner: Haus Rucker-Co. B 9.3 Klagenfurt, 1 992, p. 20 Vincent Monthiers, Paris (F) B 9.4 Michael Reisch, Cologne (D) B 9.6 B 9.8 Paul Ott, Graz (A) Roland Halbe/artur, Cologne (D) B 9.9 B 9. 1 0 ILEK, Stuttgart University (D) B 9. 1 1 Swissfiber AG, Zurich (CH) B 9. 1 2 Constant in Meyer, Cologne (D) Lucio Blandini/lnstitute of Lightweight Building, B 9. 1 4 Planning and Design, Stuttgart University (D) B 9. 1 5 Roger Ressmeyer/Corbis, ousseldorf (D) B 9. 1 7a BettmannlCorbis, ousseldorf (D) B 9. 1 7b Torsten Seidel, Berlin (D)

Part C Applications of building materials C

Manfred Hegger, Kassel (D)

The building envelope C 1.1 Alexander Beck, Frankfurt am Main (D) C 1 .4 Araldo de LucalCorbis, ousseldorf (D) C 1 .5 from: Hofmann, Werner; Kultermann, Udo: Baukunst unserer Zeit, Essen, 1 969, p . 1 61 Jochen Helle/artur, Cologne (D) C 1 .8 Bill Timmermann, Phoenix (USA) C 1 .9 C 1 . 1 0 Christian Kandzia, Stuttgart (D)

275

Picture credits

C 1 . 1 2 Balthazar Korab, Minneapolis (USA) C 1 . 1 7a Helene Binet, London (GB), from: Peter Zumthor Works, Basel, 1 998, p. 57 C 1 . 1 7b Theo Ott Holzschindeln GmbH, Ainring (D) C 1 . 1 7c I g nacio Martinez, Hard (A) C 1 . 1 7d Ruedi Walti, Basel (CH) C 1 . 1 7e Sampo Widmann, Munich (D) C 1 . 1 7f Helene Binet, London (GB), from: Peter Zumthor Works, Basel, 1 998, p . 42 C 1 . 1 7g Heinrich Helfenstein, ZOrich (CH) C 1 . 1 7h Christian Richters, MOnster (D) C 1 . 1 7i Christian Cerliani, ZOrich (CH) C 1 . 1 7j Michael Awad, Toronto (CON) C 1 .20a Frank Kaltenbach, Munich (D) C 1 .20b Jan Bitter, Berlin (D) C 1 .20c Jean Luc Oeru, Liege (B) C 1 .20d Christian Richters, MOnster C 1 .20e Oavid Oernie, Cambridge (GB) C 1 .20f Stefan MOller-Naumannlartur, Cologne (D) C 1 .22a Manfred Hegger, Kassel (D) C 1 .22b Hisao Suzuki, Barcelona (E) C 1 .22c Dieter Leistner/artur, Cologne (D) C 1 .22d Reinhard Goerner/artur, Cologne (D) C 1 .23a-b Kind-Barkauskas, Friedbert, et al . : Concrete Construction Manual, MunichIDOsseldorf 2002, p. 67 C 1 .23c Verlag Bau+ Technik, OOsseldorf (D) C 1 .23d-e Oyckerhoff AG, Wiesbaden (D) C 1 .23f Verlag Bau+ Technik, OOsseldorf (D) C 1 .23g Oyckerhoff AG Wiesbaden (D) C 1 .23h Kind-Barkauskas, Friedbert, et a l . : Concrete Construction Manual, Munich! OOsseldorf 2002, p. 75 C 1 .27a Klaus Kinold, Munich (D) C 1 .27b Christoph Kreutzenbeck, Wuppertal (D) C 1 .27c Frank Kaltenbach, Munich (D) C 1 .27d Ruedi Walti, Basel (CH) C 1 .27e Klemens Ortmeyer/architekturphoto, OOsseldorf C 1 . 27f Bruno Klomfar, Vienna (A) C 1 .27g from: McCarter, Robert: Frank L10yd Wright, London, 1 997, p . 1 74 C 1 .27h Arjen Schmitz, Maastricht (NL) C 1 .27i Manuel Zoller, Munich (D) C 1 .27j Stefan MOller, Berlin (D) C 1 .29a Bitter Bredt Fotografie, Berlin (D) C 1 .29b Klaus Frahrnlartur, Cologne (D) C 1 .29c Paul Raftery/view/artur, Cologne (D) C 1 .29d Katsuhisa Kida, Tokyo (J) C 1 .2g e EmbacherVienna, Vienna (A) C 1 . 29f Gert Walden, Vienna (A) C 1 .32a Richard Weston, Cardiff (GB) C 1 .32b Oennis Gilbertlview/artur, Cologne (D) C 1 .32c Paul Smoothy, London (GB) C 1 .32d Frank Kaltenbach, Munich (D) C 1 .33 Jan Bitter, Berlin (D) C 1 .36a Werner Sobek Ingenieure, Stuttgart (D) C 1 .36b from: Grimm, Friedrich: Energieeffizientes Bauen mit Glas, Munich, 2004, p. 55 C 1 .36c Margherita Spiluttini, Vienna (A) C 1 .36d Bruno Klomfar, Vienna (A) C 1 .36e Christian Richters, MOnster (D) C 1 .36f Frank Kaltenbach, Munich (D) C 1 .37 Manfred Hegger, Kassel (D) C 1 .40 Oelugan + Meissl, Vienna (A) C 1 .45 Rene van Zuuk, Almere (NL) C 1 .46a H. MOller/F 1 0nline, Frankfurt am Main (D) C 1 .46b Rathscheck Schiefer- & Oachsysteme KG, Mayen (D) C 1 .46c Iko Oachschindeln GmbH, Coswig (D) C 1 .46d Manuel Zoller, Munich (D) C 1 .46e Eternit-Werke L. Hatschek AG, Vbcklabruck (A) C 1 .46f Braas GmbH, Oberursel (D) C 1 .46g-h Manuel Zoller, Munich (D) C 1 .51 Britta Frenz, OOsseldorf (D) C 1 .54 re-natur GmbH, Ruhwinkel (D) C 1 .55 ZinCo GmbH, Unterensingen (D) C 1 .56 after: Koch, Klaus-Michael: Bauen mit Membranen, Munich, 2004 C 1 .57 Oliver Heissner, Hamburg (D) C 1 .58 Serge Du Pasquier, Preverenges (CH) C 1 .60 Hans Neudecker, Leutkirch (D) C 1 .61 Peter KneffeVpicture alliance/dpa

276

Insulating and sealing from: Behling, Sophia & Stefan: Sol Power, C 2.1 Munich, 1 996, p. 1 9 C 2.8 Frank Kaltenbach, Munich (D) C 2.9a Frank Kaltenbach, Munich (D) C 2.9b Holzabsatzfonds, Bonn (D) C 2.9c-e Frank Kaltenbach, Munich (D) Dirk FunhofflBASF AG, Ludwigshafen (D) C 2.9f C 2.9g Frank Kaltenbach, Munich (D) C 2 . 1 3 Roland Halbe/artur, Cologne (D) C 2 . 1 5 Christian Richters, MOnster (D) C 2 . 1 6 Richard Weston, Cardiff (GB) C 2 . 1 7 Ludwig Abache, London (GB) C 2.21 Isover, Mannheim (D) Building services C 3.1 Manfred Hegger, Kassel (D) Walls C 4.1 C 4.4

Wolfgang Volzllaif, Cologne (D) Wayne Fuji, from: Joy, Rick: Deserts Works, New York, 2002, p. 1 56 C 4.5-6 Zooey Braunlartur, Cologne (D) C 4.7 Hild & K, Munich (D) Ralph Feiner, Chur (CH) C 4.8 C 4.9 Roland Halbe/artur, Cologne (D) C 4 . 1 0 G isoton Baustoffwerke GmbH, Aichstetten (D) C 4.1 1 Steko Holz-Bausysteme AG, Uttwil (CH) C 4 . 1 2 Kim Zwarts, Maastricht (NL) C 4 . 1 3- 1 4 Roland Halbe/artur, Cologne (D) C 4 . 1 5 Olaf Heil, Dortmund (D) C 4 . 1 6 Karin Hessmann/artur, Cologne (D) C 4 . 1 8 Cheret & Bozic, Stuttgart (D) C 4 . 1 9 Roland Halbe/artur, Cologne (D) C 4.20 Richard Weston , Cardiff (GB) C 4.21 Klaus Frahrnlartur, Cologne (D) Intermediate floors Roland Halbe/artur, Cologne (D) C 5.1 C 5.5 Roland Halbe/artur, Cologne (D) G. E. Kidder-Smith!Corbis, OOsseldorf (D) C 5.6 Karl + Probst Architekten, Munich (D) C 5.7 C 5 . 1 0 Volker Auch-Schwelk, Stuttgart (D) C 5. 1 1 Erika Koch!artur, Cologne (D) C 5 . 1 2 Felix Borkenauiartur, Cologne (D) C 5 . 1 3 Roland Halbe/artur, Cologne (D) C 5 . 1 4 Christoph von Haussen/artur, Cologne (D) C 5. 1 6 Klaus Frahrnlartur, Cologne (D) C 5. 1 7 Ciro Marini/Attilio Terragni

C 6 . 1 9b-c Vorwerk Teppichwerke GmbH & Co. KG, Hamelin (D) C 6 . 1 9d-e OEKOWE SchOrholz Teppichfabrik GmbH, Oorsten (D) C 6. 1 9f Fabromont AG, Schmitten (CH) C 6.21 Eberhard Weible/design: Regine Schumann, Cologne (D) Surfaces and coatings C 7.1 Alberto Moreno GuzmanIBarragan Foundation, Birsfelden (CH) C 7 .2-3 NCS Colour Centre, Berlin (D) C 7.4 Palladium Fotodesign, Cologne (D) Gert Walden, Vienna (A) C 7.7 Hans Klumpp, Stuttgart (D) C 7.8 C 7.9 Valerio Olgiati, ZOrich (CH) C 7 . 1 2a Irene Meissner, Munich (D) C 7 . 1 2b Alexander Reichel, Kassel (D) C 7 . 1 2c Joachim Raab, Frankfurt am Main (D) C 7 . 1 2d Irene Meissner, Munich (D) C 7 . 1 2e Weber Broutin, Cologne (D) C 7 . 1 2f-g Joachim Raab, Frankfurt am Main (D) C 7 . 1 2h Manuel Zoller, Munich (D) C 7 . 1 4 Betrix & Consolascio, Erlenbach (CH) C 7 . 1 6-1 8 Vollenschaar, Dieter; Wendehorst, Reinhard: Baustoffkunde, Hannover, 2004, pp. 8 1 6, 8 1 8, figs 1 1 .2, 1 1 .3, 1 1 .5 C 7.20 Herta Hurnhaus, Vienna (A) C 7.21 Luc Boegly/Archipress, Paris (F) C 7.22 Brigida Gonzalez, Stuttgart (D) C 7.23 from: Weston, Richard: Material, Form and Architecture, Stuttgart, 2003, pp. 66 & 1 1 8 C 7.25 OaimlerChrysler Media Services C 7.26 Christian Richters, MOnster (D) Daniel Sumesgutner, Dortmund (D) C 7.27 C 7.28 Travel lnkIVisum C 7.29 lan Oobbie, London (GB) C 7.31 BerlintapetelRadomski C 7.32-33 Manuel Zoller, Munich (D)

Part D Case studies in detail p. 202 p. 204 p. 205 pp. 206, 207 pp. 208, 209 bottom pp. 2 1 0, 21 1

Floors C 6. 1 C 6.4a C 6.4b C 6.4c C 6.4d C 6.4e C 6.4f C 6.6 C 6.9a

Royalty-Free/Corbis, OOsseldorf (D) Reinhard Goerner/artur, Cologne (D) Florian Lichtblau,Munich (D) Welke GmbH, Christinendorf (D) ROdiger Krisch, TObingen (D) Raderschall Architekten, Cologne (D) Welke GmbH, Christinendorf (D) Todd GipsteinlGetty Images Elizabeth Whiting , London (GB). from: Wilhide, Elizabeth: Holz, Glas & Co., StuttgartlMunich, 2002, p . 57 C 6.9b Volker Auch-Schwelk, Stuttgart (D) C 6.9c OASAG GmbH & Co. KG, Neuwied (D) C 6.9d Manuel Zoller, Munich (D) C 6. g e OASAG GmbH & Co. KG, Neuwied (D) C 6.9f ARGE Pflasterklinker e.v. Bonn (D) C 6.9g Manuel Zoller, Munich (D) C 6.9h Richard Weston, Cardiff (GB) C 6 . 1 2a-c Bembe Parkett, Bad Mergentheim (D) C 6 . 1 2d Manuel Zoller, Munich (D) C 6 . 1 2e-g Bembe Parkett, Bad Mergentheim (D) C 6 . 1 2h Holzbaumarkt PgmbH, BOllingen (B) C 6 . 1 3a-b Tarkett AG, Frankenthal (D) C 6 . 1 3c Haro GmbH, Stephanskirchen (D) C 6 . 1 3d Freudenberg Bausysteme KG, Weinheim (D) C 6 . 1 3e Tarkett AG, Frankenthal (D) C 6 . 1 4 Tarkett AG, Frankenthal (D) C 6 . 1 5- 1 6 from: van Onna, Edwin: Material World, Basel, 2003, pp. 25 & 61 C 6.1 7 Oavid Joseph, New York (USA) C 6 . 1 9a Tarkett AG, Frankenthal (D)

pp. 2 1 4, 2 1 5 pp. 2 1 6, 2 1 7 p p . 2 1 8, 2 1 9 p p . 220, 221 pp. 222, 223 left p. 223 right p . 224 p. 225 top, centre pp. 229-232 p. 233 p. 237 p . 238 p . 239 pp. 240, 241 pp. 242, 243 top p. 243 bottom p. 244 p . 245 pp. 248-250 pp. 25 1 , 252 top pp. 252 bottom, 253 pp. 254, 255 pp. 256, 257 pp. 258, 259 p. 260 top p. 260 bottom p . 262

Manfred Hegger, Kassel (D) Ignacio Martinez, Hard (A) Bruno Klomfar, Vienna (A) Filippo Simonetti, Brunate (I) Serge Oemailly, Saint Cyr Sur Mer (F) Eduard Hueber/archphoto, New York (USA) Richard Oavies, London (GB) Philippe Ruault, Nantes (F) Christina Kaufmann, Bern (CH) Jean Michel Landecy, Genf (CH) Oidier Boy de la Tour, Paris (F) Jan Meyer, Paris (F) Ralf Richter/architekturphoto, OOsseldorf (D) Hans Pattist, Krimpen ad Yssel (NL) Shinkenchiku-sha, Tokyo (J) Katsuhisa Kida, Tokyo (J) Roland Halbe/artur, Cologne (D) Brigida Gonzalez, Stuttgart (D) Roland Halbe/artur, Cologne (D) Jens Passoth, Berlin (D) Thomas Jantscher, Colombier (CH) Paul Ott, Graz (A) Thomas Jantscher, Colombier (CH) Serge Oemailly, Saint Cyr Sur Mer (F) Georges Fessy, Paris (F) Robert Metsch, Offenbach (D) Eibe S6nnecken, Oarmstadt (D) Rob t' Hart, Rotterdam (NL) Werner H uthmacher, Berlin (D) Bitter Bredt Fotografie, Berlin (D) Christian Schittich, Munich (D) Bitter Bredt Fotografie, Berlin (D) ILEK, Stuttgart university (D)

Subject index

The authors and publishers would like to express their thanks to the following per­ sons who kindly provided advice and assistance: Dr. Andreas Becht, TObingen Marc Binder, PE Europe GmbH, Leinfelden-Echterdingen Or. JOrgen Demeter, BASF, Ludwigshafen Markus Dietz, Faculty of Design and Structural Development, Darmstadt TU Joost Hartwig, Darmstadt Dr. Frank Heinlein, Werner Sobek Ingenieure GmbH, Stuttgart Verena Klar, TObingen Holger Kbnig, LEGEP, Dachau Johannes Kreissig, PE Europe GmbH, Leinfelden-Echterdingen Reiner Krug, Deutscher Naturwerkstein­ verband e.v., WOrzburg Klaus Niemann, Henkel Bautechnik GmbH, WOLFIN Bautechnik, Wachters­ bach Florian Lang, Lang + Volkwein Architekten & Ingenieure, Darmstadt Guido Ludescher, Mayr + Ludescher Beratende Ingenieure, Stuttgart Margit Pfundstein, BASF, Ludwigshafen Adolf Rosenkranz, Schbnau Michael Wichmann, Henkel Bautechnik GmbH, WOLFIN Bautechnik, Wachters­ bach

Subject index A abrasion resistance -> 39, 4 1 -43, 48, 1 90, 1 98 acid-etched glass -> 1 1 , 1 07 acidification potential -> 24, 99 acoustic plaster -> 1 90 acrylate sealant -> 1 43 acrylic paints -> 1 95, 269 adaptive glazing -> 89 additive -> 1 53, 1 87, 1 99, 269 adhesive -> 44, 53, 57, 62, 63, 65, 7 1 , 74, 78, 94, 96, 97, 1 2 1 , 1 23, 1 25-1 27, 1 35, 1 38, 1 41 , 1 43-145, 1 60, 1 71 , 1 74, 1 76, 1 80, 1 8 1 , 1 83, 1 85, 1 9 1 , 1 94 , 201 , 225, 268, 269 admixtures -> 56-58, 1 88 aerated concrete -> 60, 61 , 1 00, 1 56, 1 65, 1 66 aerogel -> 1 4, 1 40 Agenda 21 -> 1 8 aggregate -> 25, 47, 56, 57, 59, 60, 61 , 99, 1 1 2, 1 37, 1 56, 1 61 , 1 72, 1 73, 1 77, 1 89, 1 91 , 201 , 2 1 0, 2 1 1 airborne pollutants -> 39, 99, 1 89 airtightness -> 26, 1 32, 1 39, 1 42, 1 45 air cavity -> 1 05- 1 07, 1 1 0--1 1 2 air change rate -> 26, 1 42 air conditioning -> 1 46, 1 50 alkyd resin -> 1 79, 1 85, 1 93, 1 95, 1 99, 201 , 269 aluminium -> 1 1 , 23, 48, 56, 64, 77-79, 81 , 83, 85, 89, 1 07, 1 1 0, 1 1 1 , 1 1 3-1 1 7 , 1 1 9, 1 2 1 , 1 22, 1 24, 1 38, 1 39, 1 43-145, 1 48-1 5 1 , 1 57, 1 68, 1 7 1 , 1 80, 1 9 1 , 1 98, 1 99, 209, 2 1 5, 225, 227, 228, 24 1 , 243, 244, 248, 249, 255, 257-260, 264 , 268 anhydrite binders -> 55 animal fibres -> 1 83 anisotropy -> 67, 68, 72 anti-glare applications -> 89 anti-graffiti coatings -> 200 antistatic floor coverings -> 1 75, 1 83 aquatic ecotoxicity -> 24

aramid fibres -> 92, 95 arch -> 1 63, 1 65 arsenic -> 268 asbestos -> 1 1 3, 1 35, 268, 269 ashlar walling -> 42, 1 55 asphalt shingles -> 63, 1 07, 1 2 1 , 1 22, 1 31 B bakelite -> 90 ballast -> 56, 57, 63 bamboo -> 1 79, 2 1 2, 2 1 3 basalt -> 1 0, 40, 41 , 1 1 0, 1 1 2 , 1 1 3, 1 36, 256 basement -> 26, 1 25, 1 27, 1 36-1 38, 1 43, 1 44, 1 62, 1 89, 1 90, 207, 2 1 8, 226, 269 beam -> 66, 7 1 -73, 1 55, 1 63-167, 205, 209, 2 1 1 , 2 1 3-2 1 5, 2 1 7, 223, 230, 237, 239, 246, 255 behaviour in fire -> 57, 1 60, 1 66, 1 99, 265 biocides -> 268 bitumen emulsion -> 62, 63, 65, 1 4 1 bitumen solution -> 62 bituminous coating -> 209 block-on-edge parquet -> 1 78, 1 79, 1 84 block board -> 72-74 blower door -> 26, 1 42 blowing agent -> 60, 1 36-138 blown bitumen -> 62, 63, 65 blown cylinder sheet glass -> 84 boiling point -> 26, 65, 91 , 264 bonded screed -> 1 71 borosilicate glass -> 86 bracing -> 70, 7 1 , 73, 74, 80, 1 1 2, 1 52, 1 58, 1 60, 1 62, 236 brass -> 65, 82, 83, 1 48 brick arch floor -> 1 63 bronze -> 76, 77, 79, 83 building envelope -> 1 0, 38, 52, 65, 79, 87, 1 03-106, 1 1 1 , 1 1 8, 1 20, 1 33, 1 42, 1 44, 1 53, 1 54, 1 86, 232, 240, 254 building materials class -> 47, 265 building performance -> 27, 99, 1 06, 1 07, 1 1 0-1 1 2 , 1 20, 1 29, 1 33-135, 1 53, 1 70, 1 73, 1 88, 1 94, 1 96, 1 98, 1 99 building services -> 1 2 , 20, 25, 90, 1 05, 1 46, 1 53, 1 56, 1 58, 1 63, 1 64 , 1 67, 1 68 C cable duct -> 243 cable net -> 78, 1 1 7 CAD -> 33, 34 calcium silicate insulating boards -> 1 36, 1 68 calcium silicate units -> 60 calcium sulphate screed -> 1 72-174 calendering -> 93 calorific value -> 94, 98-1 00 capillary action -> 51 , 1 44, 1 58, 1 90, 1 9 1 , 1 94, 1 97, 1 99 capillary water absorption -> 1 88, 1 96 carbon dioxide -> 23, 26, 55, 59, 67, 75, 82, 95, 99, 1 0 1 , 1 32, 1 35, 1 37, 1 38, 1 43, 1 89, 1 94-196, 1 98, 268 carbon dioxide emissions -> 23 carbon dioxide permeability -> 1 95, 1 96 carbon fibre -> 33, 34 casting -> 76, 79, 80, 83-85, 87, 92, 95, 1 01 , 1 1 5, 1 48, 1 64, 1 65, 266 cast glass -> 84, 86, 1 95 cast iron -> 76, 79, 80, 1 49, 264 ceiling -> 61 , 1 66 cellular glass -> 86, 1 33, 1 34, 1 36, 1 4 1 , 1 73, 205, 240, 241 , 243, 244 , 250 cellulose fibre -> 1 39 cell ceilings -> 1 67, 1 68 cement-based sealants -> 1 44, 1 45 cement-bonded particle board -> 1 09 cement fibreboard -> 60, 1 00 cement screed -> 61 , 1 70--1 74, 243, 257 ceramic panels -> 1 07, 1 1 1 , 1 1 9 ceramic tiles -> 1 1 , 53, 1 1 1 , 1 60, 1 761 78, 1 85, 2 1 5, 246 CFC -> 99, 268

characteristic strength -> 266 chemical passivation -> 1 97 chippings -> 47, 57, 63, 64, 1 23, 1 27, 1 73, 204 chloroprene rubber -> 93, 97, 1 49 chromium -> 1 6, 63, 77, 80, 81 , 1 48, 1 49, 1 93, 269 cladding -> 1 1 , 1 7, 38, 39, 4 1 , 42, 46, 47, 5 1 , 53, 60, 6 1 , 7 1 , 72, 77, 8 1 , 87, 90, 99, 1 07-1 1 6, 1 34, 1 35, 1 52, 1 53, 1 58, 1 86, 1 98, 226, 228, 256 clayey shale -> 40, 4 1 , 43 clayware -> 49 clay brick -> 46, 49, 50, 5 1 , 57, 1 36, 1 53, 1 54, 1 55, 1 72, 1 73, 204 clay brickwork -> 1 0 , 1 04, 1 1 3, 1 53, 1 55, 203, 220, 245, 258 clay element -> 245, 246 clay roof tile -> 53, 1 23 clay tile subfloor -> 1 74 coefficient of thermal expansion -> 68, 81 , 86, 91 , 94, 1 1 3, 1 76, 1 99, 265 cold deck -> 1 20 colour reference systems -> 1 87 colour rendering index -> 266 colour wheel -> 1 86, 1 87 combustibil ity class -> 74 comfort -> 1 8, 22, 23, 26, 27, 34, 1 04, 1 06, 1 1 6, 1 33, 1 46, 1 75, 1 80--183, 206 composite beams -> 1 64 composite boards -> 61 composite flat slab -> 1 62, 1 63 composite floor -> 1 63, 1 64, 207 compressive strength -> 1 7, 40-42, 45, 47, 48, 50, 5 1 , 55, 56, 58-60, 63, 68, 80, 81 , 85, 1 27, 1 35, 1 37, 1 39, 1 52, 1 56, 1 7 1 , 1 73, 1 75, 1 88, 1 90, 1 98, 264, 266 computer -> 1 0 , 1 4, 1 6-1 9, 25, 34, 35, 1 00, 1 46, 1 7 1 concrete cover -> 57, 59, 1 1 2, 1 63, 1 65 concrete mix -> 1 0, 59, 1 1 2 concrete plank floor -> 1 63 concrete roof tile -> 1 23, 1 24 concrete topping -> 60, 1 63-1 65, 1 67 , 207 condensation -> 1 06, 1 07, 1 1 4, 1 1 5, 1 42, 245 conductive floor coverings -> 1 75 construction joints -> 1 42 contact adhesives -> 97 convection -> 25, 26, 29, 88, 1 42 copper -> 24, 64, 76-78, 8 1 -84, 1 1 3, 1 1 4, 1 1 8, 1 1 9, 1 2 1 , 1 24, 1 3 1 , 1 47-149, 1 5 1 , 1 82, 248, 249, 269 core plywood -> 72-74, 1 01 , 1 07, 1 09, 1 59, 1 60, 1 67, 205 cork floor coverings -> 1 80 corrosion -> 1 0 , 59, 78-80, 82, 83, 99, 1 1 0, 1 1 4, 1 24, 1 47-1 50, 1 93, 1 95, 1 97 , 1 98 corrosion protection -> 78 corrugated bitumen sheets -> 1 24 corrugated fibre-cement sheets -> 1 24 cotton cloth -> 1 30 crack -> 85, 87, 1 42, 1 8 1 , 1 96, 251 cracking -> 58, 59, 63, 69, 70, 7 1 , 74, 9 1 , 1 1 3, 1 42, 1 66, 1 70, 1 7 1 , 1 88, 1 89, 1 93, 1 96 cross-laminated timber -> 73, 1 58, 1 67 cross-l inked polyethylene -> 1 47, 1 48, 1 50, 1 5 1 curing -> 55, 56, 58-60, 62, 63, 95, 96, 1 43, 1 44, 1 64, 1 72, 1 77 , 1 80, 1 94, 1 95, 251 curtain wall -> 84, 1 04, 1 1 0-- 1 1 2, 242

o damp-proof course -> 1 44, 1 99 damp-proof membrane -> 1 79, 1 8 1 , 21 1 , 2 1 5, 225, 243, 257 DOT -> 268, 269 demolition -> 20--2 2, 25, 98, 1 46, 1 55, 268

density -> 1 4, 29, 30, 39, 43, 46, 49-5 1 , 56-58, 60, 61 , 68, 70, 72, 74, 77, 81 , 86, 9 1 -94, 1 01 , 1 1 3, 1 26, 1 30, 1 47, 1 50, 1 53, 1 56, 1 59, 1 60, 1 70, 1 82, 1 90, 1 93, 208 diffusion -> 22, 46, 47, 5 1 , 63, 70, 73, 74, 1 05, 1 24, 1 42, 1 45, 1 48, 1 50, 1 66, 1 72, 1 74 , 1 80, 1 84, 1 88, 1 89, 1 90, 1 95, 1 96, 1 98, 1 99, 200 diffusion-equivalent air layer thick­ ness -> 1 88 diffusion resistance -> 1 45, 1 96 dimensional coordination -> 1 1 3, 1 55, 1 56 DIN colour system -> 1 87 dioxin -> 268 discoloration -> 51 double-leaf masonry -> 57, 1 1 1 double-skin roof -> 1 20, 1 22, 1 28 double glazing -> 85, 88, 1 1 6, 1 1 9, 207, 209, 2 1 1 , 2 1 4 , 2 1 5, 2 1 9, 221 , 225, 241 , 243, 246, 249, 253, 254, 257, 259, 260 drainage layer -> 1 28, 253 dressed stone -> 42 drinking water -> 63, 94, 96, 99, 1 44, 1 46-148, 1 50 dry coat thickness -> 1 96, 1 97, 1 99 duopitch roof -> 1 22 durability -> 1 8, 20, 21 , 23, 25, 26, 35, 39, 48, 49, 52, 64, 66, 68, 75, 82, 83, 98, 99, 1 06, 1 08, 1 1 0, 1 22, 1 26, 1 29, 1 30, 1 45, 1 47-1 5 1 , 1 57 , 1 8 1 , 1 86, 1 92-194, 1 97, 1 98, 208 E earthenware -> 49, 53, 1 75, 1 77, 1 84 earthquakes -> 1 62 eaves -> 75, 1 08, 1 09, 1 22-124, 1 97, 217 ecosystem -> 2 1 , 22 efflorescence -> 51 elastomer -> 64, 65, 95, 1 44, 1 49 electrical conductivity -> 77, 1 73, 1 75 electrical installations -> 1 46, 1 51 electrochemical series -> 78, 1 97 electrogalvanising -> 82 electrostatic behaviour -> 1 75 elongation at failure -> 80 emissivity -> 88 enamelling -> 87 end-grain wood-block flooring -> 1 78, 1 79 end grain -> 7 1 , 1 09 energy economy -> 1 42 energy requirement -> 22-24, 49, 79, 83 engineering brick -> 50, 5 1 , 53, 1 01 , 1 07, 1 55, 1 7� 1 77, 1 84 engobe -> 49, 52 environmental audits -> 1 9 environmental compatibility - > 1 9 environmental effects -> 1 8 , 22, 23, 24, 25, 98 environmental impact -> 1 8, 1 9, 23-26, 98 Environmental Product Declarations -> 98 EPDM -> 93, 95, 97, 1 01 , 1 1 9, 1 27, 1 3 1 , 1 44 , 1 45, 1 48-1 5 1 , 207, 21 1 , 223, 255 epoxy resin -> 1 0 1 , 1 99 equilibrium moisture content -> 68 eutrophication potential -> 24, 99 expanded clay -> 46, 57, 60, 1 1 0, 1 28, 1 3 1 , 1 56, 1 65 expanded metal -> 1 2 , 1 1 5, 1 68, 1 89 expanded perlite -> 201 expanded polystyrene foam -> 1 5, 1 6, 29, 30, 207, 231 expansion joint -> 1 1 2, 1 43, 1 79 external wall -> 1 3 , 5 1 , 87, 1 0 1 , 1 05-1 07, 1 09-1 1 1 , 1 1 5, 1 1 8, 1 2 1 , 1 42, 1 97 extrusion -> 79

277

Subject index

F facade --> 1 1 -1 3, 1 5, 1 7, 24, 38-42 , 53, 60, 73, 77, 81 , 83, 84, 90, 92-94, 96, 99, 1 03-105, 1 07-1 1 9, 1 95-1 97, 206, 207, 2 1 4-2 1 6, 220, 226, 229, 230, 234, 237, 239-245, 248, 249, 251 , 252, 256, 259, 260 fair-face concrete --> 1 0, 1 1 , 54, 56, 58, 1 1 2, 1 53, 1 54, 1 94, 2 1 2, 2 1 8, 220, 242, 251 fastener --> 1 24, 1 26, 257 ferrous metal --> 81 fibre-reinforced plastic --> 96, 1 1 5, 1 24 fibreboard --> 60, 72, 74, 1 00, 1 31 , 1 59, 1 60, 1 69, 1 80, 231 fibre composite --> 29, 1 74, 1 83 fibrous plasterboard --> 60, 1 69 filler --> 55, 59, 68, 1 65, 1 89, 269 film formation --> 1 93 filter --> 1 27, 1 28, 1 31 , 1 86, 229 finish coat --> 1 89- 1 91 , 1 94, 1 97-199 fire-resistant glass --> 85, 88 fire protection --> 57, 60, 61 , 78, 87, 1 06, 1 08, 1 1 4, 1 46, 1 50, 1 58, 1 63, 1 65, 1 67 , 1 70, 1 88, 1 90, 1 99, 268, 269 fire resistance --> 1 6, 60, 1 50, 1 53, 1 561 58, 1 60, 1 63, 1 65, 1 66, 1 90, 1 99, 242 fittings --> 1 3, 26, 83, 89, 1 47-1 51 , 1 74, 222 flag --> 53, 1 76 flatweave carpets --> 1 82 flat roof --> 53, 62, 64, 1 20, 1 25, 1 26 flat slab --> 1 62-164, 1 66 flax --> 1 80 flexible bitumen sheeting --> 64, 1 25, 1 2 flexible polymer-modified bitumen sheeting --> 63, 64 flexible waterproof sheeting --> 64, 1 25 floating screed --> 1 66, 1 70, 1 7 1 float glass --> 84, 86-88, 1 07 flooring-grade board --> 60 flooring cement --> 1 72, 1 73, 1 75 floor covering --> 25, 39, 57, 90, 99, 1 70-183, 2 1 3 floor finish - -> 41 , 1 70, 1 73-1 75, 1 81 foamed plastics --> 90 form-finding --> 34 formaldehyde --> 27, 30, 70, 7 1 , 90, 91 , 93, 97, 268, 269 formwork --> 1 0, 1 6, 46, 54, 57-59, 7 1 , 1 1 0, 1 1 2, 1 53-1 55, 1 57, 1 63-165, 1 97, 204, 2 1 2 , 2 1 3, 242, 251 formwork panel --> 1 0 formwork tie --> 1 0, 1 54, 1 55, 251 foundation --> 90, 98, 1 05, 1 29, 1 42, 1 44, 2 1 4 , 225, 232, 245 frost resistance --> 4 1 , 42, 53, 56 fungicide --> 200, 269 furan --> 268 G gabion wall --> 1 07, 1 1 0 galvanised steel --> 79, 1 47, 1 49, 1 50, 228, 230, 231 gasket --> 1 01 , 1 1 9, 1 44 glass --> 83 glass-concrete slab --> 1 63 glass brick --> 1 57 glass ceramics --> 50, 86 glass cloth --> 61 , 64, 85, 86, 97, 1 26, 1 27, 1 29, 1 30, 1 91 glass fibre --> 1 5, 1 7, 86, 95, 96, 1 1 5, 1 24, 1 28, 1 50, 1 60, 1 80 glass fleece --> 64, 86 glass wool --> 27 glaze --> 1 93-195 global warming --> 1 8, 22, 24, 98-1 01 , 268 global warming potential --> 22, 24, 99, 1 00, 1 01 , 268 glue --> 97, 1 92 glued laminated timber --> 7 1 -73, 1 66

278

granite --> 38, 40-42, 48, 1 1 3, 1 76, 1 84 granite slabs --> 38 granolithic finish --> 1 72 gravel --> 1 0, 25, 40, 45, 48, 54, 56-58, 63, 64, 1 1 2, 1 25-128, 1 31 , 1 73, 1 77 , 1 91 , 204, 2 1 8 greenhouse effect --> 22, 99 green roof --> 2 1 4 grey energy --> 23, 24 grid ceilings --> 1 67 , 1 68 grinding --> 1 0, 42, 81 , 84, 86, 87, 1 1 3, 1 54, 1 96, 1 98 groundwater --> 26, 99, 1 44 grouting --> 57 gunmetal --> 83, 1 48 gypsum --> 1 6, 1 7, 54-57, 60, 61 , 72, 82, 1 00, 1 45, 1 53, 1 55-157, 1 59, 1 61 , 1 66, 1 68, 1 69, 1 74, 1 88-190, 1 98, 1 99, 201 , 234, 241 , 259, 260 gypsum plaster --> 55, 60, 1 68, 1 69, 1 88-190, 1 99, 201 , 234, 259, 260

in situ concrete --> 25, 58, 1 07, 1 1 2, 1 1 8, 1 44 , 1 53, 1 63-165, 2 1 4, 242 iron --> 37, 48, 55, 56, 63, 76-81 , 84, 86, 1 0 1 , 1 1 2, 1 49, 1 93, 1 95, 1 97, 268 IR absorber-modified polystyrene --> 29, 1 38 isolated ceiling floor

--> 1 63

J jointing --> 64, 65, 7 1 , 78, 1 08, 1 20, 1 2 1 , 1 27, 1 42, 1 57, 1 81 joint sealant --> 1 43

H haptics --> 9, 29, 32-35 hardboard --> 72, 74 hardness --> 39, 41 , 49, 52, 61 , 68, 85, 1 47, 1 73, 1 79, 1 93, 208 hardwood --> 68, 7 1 , 1 79 hazardous substance --> 1 9, 2 1 , 23, 44, 93, 1 35, 1 76, 1 93, 1 96, 268 HCFCs --> 1 35, 1 37 heartwood --> 67, 68, 1 08 heat-absorbing insulating glass --> 88 heat-treated glass --> 85, 87, 1 1 6, 239, 259, 260 heated screed --> 1 7 1 heating system --> 1 50 heat conduction --> 29, 30, 88 heat flow --> 1 33, 1 34, 1 40 heat loss --> 1 1 8, 1 32-135, 1 40, 1 50 heat radiation --> 29, 88, 1 57 heat storage capacity --> 31 , 39, 45, 68, 1 34, 1 35, 1 38, 1 53-156, 1 63, 1 65, 1 76, 1 77, 1 90 high-density polyethylene --> 1 47 high-pressure laminate --> 1 60, 1 79 high-rise building --> 77, 84 hollow-block floor --> 1 63, 1 66 hollow-core slab --> 1 62-1 64, 1 66 hollow clay block --> 5 1 hollow clay block floors --> 5 1 hot-dip galvanising - -> 8 2 , 1 49 hot water --> 1 46, 1 47, 1 50, 1 7 1 , 200 human toxicological classification --> 24 humidity --> 46, 51 , 56, 58, 60, 78, 80, 1 05, 1 1 2, 1 28, 1 33, 1 35, 1 36, 1 42, 1 45, 1 55, 1 56, 1 59, 1 60, 1 72, 1 79, 1 89 hydration --> 55, 56 hydraulic lime --> 55, 57, 1 88-190 hydrocarbon --> 62, 91 , 1 35, 1 92, 268 hydrostatic pressure --> 65, 1 43, 1 44, 1 99 hygroscopy --> 67

L laboratory --> 27, 32, 45, 1 50 laminated floor --> 1 75 laminated glass --> 87 laminated safety glass --> 87, 1 1 6 laminated strand lumber --> 72, 74 laminated veneer lumber --> 72-74, 1 58 laminboard --> 73, 74, 1 59 lead --> 24, 25, 33, 40, 57, 70, 78, 8 1 -84, 86, 87, 96, 98, 99, 1 1 4-1 1 7 , 1 2 1 , 1 23, 1 24, 1 34 , 1 39, 1 42, 1 47, 1 48, 1 56, 1 60, 1 66, 1 70, 1 7 1 , 1 74-176, 1 78, 1 82, 1 83, 1 86, 1 88, 1 9 1 , 1 97, 2 1 0, 254 , 268, 269 levelling --> 1 37, 1 55, 1 58, 1 59, 1 70-1 72, 1 76, 207, 239, 268 lifetime --> 20 life cycle assessment --> 1 9, 23-25, 27, 42 , 67 , 72, 98, 1 00, 1 1 0, 1 39, 1 46, 1 62, 1 81 life cycle costing --> 25 lightweight loam --> 46, 47, 1 33, 1 55, 1 59 lightweight plaster --> 1 90 light transmittance --> 1 57 lignin --> 68, 75, 1 09, 1 38, 1 39, 1 98 lime --> 55, 57, 1 00, 1 89, 1 95, 1 97, 1 99, 201 limestone --> 9, 40-43, 55 lime mortar --> 49, 54, 57, 1 55, 1 90 lime plasterwork --> 1 89 lining --> 1 2 , 1 7, 46, 1 20, 1 38, 1 48, 1 52, 1 53, 1 58, 1 59, 1 60, 200, 2 1 3, 221 , 260 linoleum --> 1 80, 1 8 1 , 207 lintel --> 1 55, 221 liquid-applied waterproofing systems --> 1 25, 1 44 load bearing function --> 38, 1 58, 242 load bearing structure --> 1 0, 66, 1 1 1 , 1 1 2, 1 1 4, 1 20, 1 42, 1 52, 1 58, 206, 2 1 2, 232, 242, 254 load bearing wall --> 1 52 loam --> 1 0, 38, 44-48, 62, 1 00, 1 33, 1 53, 1 55, 1 58-1 61 , 1 73, 1 75, 1 88, 1 89, 203-205 loam brick --> 46 loam plaster --> 46, 47, 1 61 , 1 89 loam screed --> 1 73 log construction --> 66, 1 53, 1 57, 1 58, 218 Lotus Effect --> 52, 87 louvre --> 1 67 , 1 68, 222, 259, 260 low-e coating --> 88

I impact assessment --> 24, 98 impact category --> 98 impact sound insulation --> 1 34, 1 36-139, 1 66, 1 72, 1 73, 1 76, 1 79-1 82, 221 , 243, 253 industrial bitumen --> 63 infrared radiation --> 29, 88, 99 injection moulding --> 93 insect attack --> 1 38, 1 97 insulating plaster --> 1 90 insulation cork board --> 1 36, 1 38, 1 4 1 interior climate - -> 22, 24-27, 30, 44, 45, 55, 68, 1 06, 1 1 6, 1 33, 1 55, 1 56, 1 63, 1 66, 1 76, 1 79, 1 83, 1 89, 200, 208, 2 1 4 intermediate floor --> 1 63, 1 66 internal surface temperature --> 1 33 interstitial condensation --> 1 34 , 1 35, 1 42 inventory analysis --> 24, 98

M magnesia cement --> 55 magnesite flooring --> 1 72 maintenance --> 1 9-21 , 25, 1 1 4, 1 1 6, 1 23, 1 46, 1 78, 1 86, 1 95, 1 98, 268 marble --> 1 0, 38, 39, 4 1 , 1 1 3, 1 72, 1 76, 1 84, 1 86, 1 92 masonry --> 42, 44, 46-5 1 , 54, 55, 57, 58, 60-62, 1 05, 1 1 0-1 1 3, 1 1 9, 1 32, 1 40, 1 46, 1 50, 1 52-1 58, 1 60-162, 1 65, 1 66, 1 89, 1 90, 1 94, 1 98, 22 1 , 254 masonry bond --> 1 1 0, 1 1 1 mastic asphalt --> 63, 65, 1 37, 1 45, 1 721 77 , 269 media facade --> 1 2 medium board --> 72, 74 medium density fibreboard --> 74 melamine resin --> 31 , 95, 1 33, 1 60, 1 79, 1 85

melting point --> 77, 79, 80 membrane --> 1 29, 1 30, 1 79, 1 81 , 203, 21 1 , 2 1 5, 225, 243, 257, 261 , 263 metal mesh --> 83 microbial volatile organic compounds --> 268 mineral-fibre insulation --> 1 38, 1 74, 207 mineral binder --> 73, 1 56, 1 67, 1 69, 1 76, 1 90, 1 98 mineral fibre --> 1 38, 257, 259, 260, 269 mineral wool --> 1 28, 1 33-135, 1 41 , 1 61 , 1 91 , 207, 249 mixing colours --> 1 87 modular system --> 96, 245 modulus of elasticity --> 70, 78, 80, 91 , 1 90 moisture content --> 67, 68, 70-72, 75, 1 00, 1 09, 1 1 0, 1 38, 1 72, 1 75, 1 79, 1 83, 1 97 , 1 98 moisture control --> 1 06, 1 32, 1 34, 1 58, 1 70 monopitch roof --> 1 22 mortar --> 38, 42, 45-49, 51 -57, 60, 62, 82, 85, 86, 1 07, 1 1 0, 1 1 1 , 1 1 6, 1 1 8, 1 1 9, 1 23, 1 27, 1 28, 1 35, 1 37 , 1 4 1 , 1 54-157, 1 60, 1 61 , 1 71 , 1 72, 1 76, 1 77, 1 84, 1 85, 1 88, 1 90, 1 91 , 208, 239, 253, 257 mosaic parquet --> 1 78, 1 79, 1 84, 1 85 MS polymer sealants --> 1 43 multi-layer wall --> 1 52, 1 58, 1 59 multi-walled sheets --> 1 1 5 N nanocellular foam --> 30 natural asphalt --> 48, 62, 63, 65 Natural Colour System --> 1 87 natural lighting --> 24 natural rubber --> 90, 1 80 natural stone --> 1 0, 1 1 , 38, 39, 42, 99, 1 07, 1 1 0, 1 1 3, 1 36, 1 55, 1 75-177, 1 81 , 1 84, 1 98 noise --> 26, 1 06, 1 47, 1 48, 1 50, 1 56, 1 68, 240 non-ferrous metal --> 81 non-hydraulic lime --> 55, 57 non-hydrostatic pressure --> 65, 1 44 non-load bearing wall --> 1 52 non-slip --> 42, 1 75-1 77, 1 80, 1 81 normal-weight concrete --> 25, 59 nutrification potential --> 24

o one-part coating --> 1 94 optical density --> 86 opus caementitium --> 48, 54 organic fibres --> 27 oriented strand board --> 72, 74 overhead glazing --> 87, 1 1 6 Oxidised ceramics --> 49 ozone depletion potential --> 22, 24, 99

p paint --> 1 5, 78, 1 1 2, 1 43, 1 67, 1 88, 200, 207, 225, 234, 241 Pantone colours --> 1 87 paper wallpaper --> 200 paraffin --> 30, 31 , 62, 1 38, 1 90 parallel strand lumber --> 7 1 -73 parapet --> 2 1 0, 21 1 , 221 parquet flooring --> 1 78-180 particleboard --> 72, 74, 1 07, 1 09, 1 1 9, 1 59-1 61 , 1 68, 1 69, 1 74, 1 80, 1 81 , 251 partition --> 12, 27, 47, 50, 74, 96, 1 34, 1 38, 1 39, 1 42, 1 52, 1 53, 1 58-160, 1 62-164 patent glazing --> 1 1 6, 1 1 7, 1 1 9, 1 2 1 patination --> 82 patterned glass --> 85, 86, 1 1 6 pavers --> 1 77, 253 paving-grade bitumen --> 62, 63 pentachlorophenol --> 269 perceived temperature --> 1 75 perforated brick --> 46, 50, 51 perimeter joints --> 1 71

Subject index

perlite building boards -> 1 60 permanent formwork -> 1 38, 1 4 1 , 1 53, 1 64, 1 65, 2 1 3 pesticide - > 1 39, 1 93, 1 94, 268 petroleum -> 62, 63, 91 , 1 37, 268, 269 phase change material -> 30 phenolic resin -> 73, 74, 90, 93, 97, 1 33 photochemical ozone creation potential -> 24 pH value -,> 99, 1 47 , 1 48, 1 50, 1 98 pigment -'> 92, 1 94, 1 95, 1 97, 205, 242, 243, 253 pile carpet -'> 1 82, 1'83 pipe -'> 52, 83, 1 26, 1 47-1 5 1 , 1 7 1 , 268 pipe insulation -'> 1 50 pitch -'> 52, 63, 64, 1 1 6, 1 20-125, 1 28, 236 plain concrete -'> 59 plant-bearing layer -'> 1 28, 1 31 , 208, 209, 2 1 5 plaster -'> 30, 46, 47, 49, 5 1 , 54, 55, 60, 61 , 1 05, 1 07, 1 38, 1 39, 1 43, 1 45, 1 56, 1 57, 1 60, 1 6 1 , 1 68, 1 69, 1 86, 1 88-1 92, 1 94, 1 99, 201 , 21 9, 221 , 234, 259, 260, 268 plasterboard -'> 30, 60, 61 , 1 00, 1 39, 1 59-1 61 , 1 66, 1 69, 1 72, 1 74, 207, 2 1 1 , 231 , 232, 235, 246 plastering mix -'> 1 88 plasterwork -'> 1 88, 1 89, 201 plasticised PVC -'> 94, 1 51 plasticiser -'> 57 plastic forming -'> 93 plywood -'> 1 2 , 1 4, 72-74, 1 01 , 1 04, 1 07, 1 09, 1 1 9, 1 40, 1 58- 1 61 , 1 67, 1 75, 1 81 , 1 93, 205, 209-21 1 , 2 1 3-21 5, 2 1 7, 225, 227 polished plate glass -> 84, 85 polishing -'> 1 0, 39, 42, 83, 84, 1 1 3, 1 48, 1 49, 1 54 pollutant -'> 1 8 pollution -'> 2 1 , 26, 41 , 261 polybutene -'> 1 50, 1 51 , 1 81 polycarbonate -'> 1 4, 92, 93, 95, 97, 209, 255 polycarbonate double-walled sheet -> 209 polychlorinated biphenyls -> 269 polyester -'> 1 5, 64, 91 , 92, 93, 95, 97, 1 24-131 , 1 33, 1 36, 1 37, 1 39, 1 44, 1 73, 1 75, 1 8 1 , 1 84, 1 92, 1 94, 201 , 224, 225, 261 , 263, 269 polyethylene -'> 64, 88, 91 , 93, 94, 96, 1 25, 1 27 , 1 28, 1 31 , 1 41 , 1 45, 1 47-1 51 , 1 74, 1 81 , 1 85 polyisobutylene -> 93, 97 polymer-modified bitumen -'> 62-65, 1 25, 1 44, 1 45, 243, 253 polymerisation -'> 91 , 93 polymethyl methacrylate -'> 91 polyolefin --> 93, 1 81 polypropylene -> 64, 93-96, 1 26, 1 47-1 51 , 1 75, 1 81 polystyrene --> 1 5, 1 6, 29-31 , 50, 57, 61 , 91 , 93, 94, 96, 1 25, 1 26, 1 28, 1 31 - 1 33, 1 36-139, 1 4 1 , 1 50, 1 57, 1 90, 1 9 1 , 1 99, 207, 224, 231 , 243 polysulphide sealants -> 1 43 polytetrafluoroethylene --> 93-95, 97, 1 01 polyurethane -'> 1 5, 1 6, 24, 29, 7 1 , 74, 92, 96, 97, 1 25, 1 26, 1 28, 1 33, 1 36-138, 1 41 , 1 43, 1 44, 1 45, 1 50, 1 73, 1 79, 1 82, 1 85, 1 95, 1 97, 1 98, 1 99, 201 , 233, 245, 246, 254, 269 polyurethane sealants -> 1 43 polyvinyl acetate --> 97, 1 4 1 , 1 85, 200 polyvinyl chloride -> 91 , 1 45, 1 47-1 50, 1 8 1 , 1 95, 1 99 ponding -'> 1 08, 1 1 7, 1 25, 1 97 porcelain -'> 49, 50 portland cement --> 54, 56, 61 post-and-rail -> 81 , 1 1 7, 1 39, 1 40, 1 53

potassium water glass -> 1 92, 1 94, 1 95 powder coating --> 1 24, 1 48, 1 98 pozzolana -> 54, 55 prada foam --> 1 6 precast concrete -'> 1 5, 58-60, 1 07, 1 1 2, 1 43, 1 57, 1 63, 1 65, 2 1 7 pressed glass -'> 85, 86, 1 07 prestressed hollow-core slabs --> 1 64 primary energy input -'> 1 8, 24, 27, 98-1 00 primer -> 1 43, 1 89, 1 93, 1 94, 1 96-201 , 254 profiled boards -'> 1 08, 1 09 profiled glass --> 84, 86, 1 1 7, 1 57 proof stress -> 80, 83 PTFE-coated glass cloth -'> 1 30 pumice aggregate --> 1 56, 1 61 , 2 1 0, 21 1 purl in -> 1 22 Q quality control

-> 27

R R&D -> 28, 29, 34 Rabitz ceiling -> 1 68 rad ioactivity --> 40 radon -> 26, 269 raised floor -> 1 70, 1 71 , 1 83, 241 , 253 real wood parquet laminate flooring -> 1 78 reconstituted stone -,> 59, 1 07, 1 1 0, 1 1 2 , 1 1 3, 1 76, 1 77 , 1 84, 209, 221 , 257 recycled aggregate -'> 25 recycled material --> 25, 83, 85 recycling -> 2 1 , 24-26, 49, 57, 59, 63, 77-82, 93, 94, 99-1 0 1 , 1 35, 1 36, 1 39, 1 46 refractory products -> 49 refurbishment -> 20, 46, 1 25, 1 39, 1 46, 1 78, 1 80, 1 90-192, 1 95, 1 98, 268 reinforced concrete -> 23, 51 , 57, 59, 62, 77, 99, 1 00, 1 42, 1 52, 1 53, 1 58, 1 61 - 1 66, 1 98, 207, 209, 2 1 1 -2 1 3, 2 1 5, 2 1 9-221 , 225, 226, 231 , 235, 239-243, 246, 249, 250, 253, 257, 259, 260 render -> 1 5, 45--49, 51 , 54, 57, 61 , 73, 1 00, 1 05, 1 07, 1 1 5, 1 34, 1 35 , 1 43, 1 45, 1 70, 1 88-1 91 , 1 94, 1 96, 1 98, 1 99, 203, 2 1 8, 2 1 9, 241 renovation plaster --> 1 90 resilient floor coverings -> 1 70, 1 80, 1 8 1 ribbed slab -'> 1 63-1 65 ridge -> 52, 66, 1 22-1 24, 2 1 6, 230, 254 ripewood -> 67, 68 rising damp -> 65, 1 44, 1 77 , 205 rock wool -> 27, 1 33, 1 35, 1 36, 2 1 9 rolling --> 64, 78, 79, 81 , 83, 85, 86, 1 25, 1 44 rooftop planting --> 1 25, 1 28, 1 29, 208, 214 roof covering -'> 52, 53, 1 20-123, 227, 231 roof pitch --> 52, 64, 1 20-124, 1 28 roof tile -> 48, 52, 53, 1 23, 1 24 root barrier -'> 1 28, 1 3 1 , 209 rotational moulding --> 93 rubber -> 1 5, 1 6, 65, gO, 91 , 93, 95, 97, 1 01 , 1 2 1 , 1 25-128, 1 43-1 45, 1 49-1 51 , 1 72, 1 75, 1 80, 1 81 , 1 84, 1 85, 1 92, 1 94, 1 97 , 269 rubber sheeting --> 1 25, 1 26, 1 45

5 safety -> 2 1 , 22, 27, 68, 81 , 85, 87, 88, 1 1 6, 1 1 9, 1 5Q 1 6 1 , 1 75, 1 7� 205, 207, 209, 2 1 9, 222, 223, 230, 239, 255, 257, 259, 260, 269 sand -> 25, 40, 45, 49, 53, 54, 56, 57, 60, 63, 64, 79, 81 , 84, 85, 87, 1 07 , 1 09, 1 1 2 , 1 1 3, 1 27, 1 36, 1 40, 1 54, 1 72-174, 1 76, 1 77, 1 89, 1 90, 224, 225, 253 sand-blastin9 -> 81 , 85, 87, 1 1 3, 1 54 sandstone -> 1 0, 39-4 1 , 43, 1 1 0, 1 76 sandwich elements --> 1 1 2 , 1 53

sandwich panel -> 1 82, 2 1 7, 260 sanitary appliances -> 26, 1 50 sapwood -> 67, 68, 75, 1 22 sawn timber -'> 69, 70, 1 07 , 1 28 sawtooth roof --> 1 22 scagliola -> 54, 55 sealing strip -> 1 44 seamless ceiling -> 1 68 sedimentary rocks --> 40, 41 , 43, 1 76 self-cleanin9 91ass --> 87 self-compacting concrete --> 58 self-levelling screed -> 1 72 separating joints --> 1 42, 1 43 separating layer -> 1 28, 1 70, 1 7 1 , 200, 207, 2 1 1 , 2 1 5, 221 , 225, 243, 253 serviceability --> 1 8, 52, 69, 1 06, 1 08, 1 45 sgraffito -> 1 91 shear wall -> 1 52, 1 58, 1 60 sheathing -> 82, 95, 1 23, 1 31 , 1 45, 1 51 sheep's wool -> 1 33, 1 36 sheet metal -> 1 1 , 1 4, 65, 78, 79, 89, 1 08, 1 1 4 , 1 1 5, 1 20-1 22, 1 24, 1 44, 1 45, 1 53, 1 58, 1 65, 1 68, 1 72, 1 75, 1 96, 2 1 0, 243, 246, 253 shell -> 54, 57, gO, 96, 226-228 shrinkage -> 44, 45, 74 shutter --> 1 55, 2 1 3, 249 silicon -> 55, 56, 77, 79, 81 , 84-86, 91 , 95, 1 1 8, 200, 268 silicone -> 1 4, 1 6, 95, 1 1 0, 1 1 6, 1 1 7, 1 1 9, 1 29, 1 30, 1 36, 1 37, 1 43, 1 5 1 , 1 57, 1 88, 1 92, 1 94, 1 95, 1 98, 223 silk-screen printin9 -> 87 single-leaf glass facade -> 1 1 6 sing le-skin roof -> 1 20, 1 22 single-storey sheds -> 72, 77 skyscrapers --> 1 8, 33, 77 slate -> 4 1 , 64, 1 1 3, 1 23, 1 84, 1 85, 207 socket --> 52, 1 48-1 51 soffit -> 1 2 , 1 34, 1 59-162, 1 64-168, 1 70, 1 90, 260 software -> 1 4, 1 9, 33-35, 1 00 softwood --> 66-69, 7 1 -73, 1 6 1 , 1 78, 1 79 solar-control glass -> 88 solar cells -> 1 1 8 solar collectors --> 96 solar energy -> 1 8, 30, 75, 86, 87, 1 1 8, 1 30 solar radiation -> 1 4, 77, 87, 88, 99, 1 1 1 , 1 1 6, 1 1 8, 1 23, 1 29, 1 40, 1 88, 237 soldering -> 79, 82, 1 20, 1 2 1 solid modular wall - > 1 52 solid timber -> 66, 68-74, 1 05, 1 08, 1 09, 1 40, 1 53, 1 58-160, 1 63, 1 66, 1 68, 1 78, 1 79, 1 99 solvent -> 26, 65, 96, 1 2 1 , 1 27, 1 43, 1 80, 1 92-195, 1 97, 1 98, 200, 269 sorption -> 45-47, 1 55, 1 56, 1 63, 1 66, 1 83, 1 89 sound absorption -> 74, 1 68 sound insulation -'> 25, 51 , 60, 61 , 74, 81 , 86, 87, 89, 94, 96, 1 06, 1 1 6, 1 30, 1 33-139, 1 42, 1 44, 1 46, 1 49, 1 53-159, 1 61 , 1 63, 1 66, 1 67, 1 70, 1 72-176, 1 79-182, 221 , 242, 243, 253, 269 spalling --> 59, 1 88 special ceramics --> 49, 50 specific heat capacity -> 43, 59, 1 34 spray plastering --> 1 91 sprung floors -> 1 74 stabiliser -> 57 stability --> 39, 49, 52, 60, 61 , 64 , 67, 7 1 -73, 87, 92, 95, 1 1 0, 1 1 1 , 1 1 4 , 1 35, 1 48, 1 5Q 1 55, 1 5� 1 5� 1 62, 1 67, 1 74, 1 76, 1 95, 204 stainless steel -> 1 2 , 77, 78, 80, 81 , 1 1 0, 1 1 4, 1 1 8, 1 1 9, 1 2 1 , 1 22, 1 24, 1 47-1 51 , 1 82, 205, 222, 223, 234, 236, 239, 248, 250, 259, 260 steel reinforcement -> 58, 1 96, 1 98 stone -'> 1 0, 1 1 , 1 3, 29, 38, 39, 4 1 - 44,

48, 54, 58, 59, 66, 76, 92, 99, 1 04, 1 07 , 1 1 0-1 1 3, 1 1 8, 1 2 1 , 1 25, 1 27, 1 36, 1 44, 1 53, 1 55, 1 62, 1 72, 1 73, 1 75-1 77, 1 80, 1 81 , 1 84-186, 1 93, 1 98, 203, 208, 209, 2 1 2 , 221 , 237, 253, 256, 257, 269 stoneware -'> 49, 50, 52, 53, 1 49, 1 77 stone facing --> 38, 54 stone tiles -> 42, 1 1 0, 1 1 1 , 1 76, 1 84, 257 straight-run bitumen -> 62, 65 straw loam --> 46 stretch coverings -'> 1 67, 200, 201 structural steelwork -'> 77, 78 structural veneer lumber (SVL) -'> 71 , 73 stucco work -> 1 0, 1 1 styrene-butadiene rubber (SBR) -'> 91 , 93 sunblind --> 243, 244 sunshading -> 1 2 , 87, 89, 1 1 6 surface treatment -'> 1 5, 38, 39, 42, 58, 1 49, 1 54, 1 60, 1 76, 1 78-180, 1 98 sustainability -> 1 8, 1 9, 22, 25, 27, 75, 98, 1 66 sustainable construction -> 9, 1 8- 21 , 23, 98, 1 04 sustainable development -> 1 8, 22, 30 swelling -'> 49, 68, 72, 1 07, 1 08, 1 1 0, 1 30, 1 88, 1 98 switchable thermal insulation --> 1 40 switches --> 35, 89 synthetic building materials -'> 21 synthetic fibres --> 90, 1 28, 1 44, 1 82-1 84, 201 synthetic material --> 87, 90-94, 96, 1 47, 1 82, 200, 201 , 203 synthetic resin screed (SR) -'> 1 73 synthetic rubber --> 1 44, 1 51 , 1 80 synthetic sheeting -'> 1 25, 1 26, 1 41 , 1 45, 219 T T-beam slab --> 1 63, 1 65, 1 66 tamped concrete -> 205 tamped loam -> 44, 45, 1 53, 1 55, 1 73, 1 75, 204 tar -> 63, 90, 268, 269 tear strength -'> 1 26, 1 30 tensile bending strength -> 74, 1 7 1 , 1 72 tensile strength --> 58, 59, 68, 80, 81 , 85, 87, 91 , 1 35, 1 76, 268 terrazzo -> 56, 1 72, 1 73, 1 75, 1 77 , 242 terrestrial ecotoxicity (ECT) -'> 24 textile floor coverings -> 1 75, 1 82-185 thatch -> 1 22 thermal break -> 85, 1 1 6, 1 34, 21 1 , 2 1 5 , 2 1 9, 243, 257 thermal bridges -'> 1 07 , 1 1 7, 1 34, 1 35, 1 37, 1 38, 1 91 thermal comfort -> 26 thermal conductivity -> 29, 30, 39, 43, 51 , 59, 60, 67, 68, 77, 81 , 83, 91 , 1 06, 1 32-135, 1 39, 1 40, 1 50, 1 53-155, 1 73, 1 76, 1 88, 1 90 thermal energy systems -> 1 1 8 thermal expansion -> 39, 68, 81-83, 86, 91 , 94, 1 1 0, 1 1 3, 1 47 , 1 48, 1 50, 1 72, 1 76, 1 99, 240 thermal insulation -> 1 4, 29, 38, 46, 50, 51 , 57, 68, 86, 88, 89, 1 05-107, 1 1 1 , 1 1 9, 1 20, 1 25, 1 28, 1 30, 1 32-140, 1 42, 1 44, 1 45, 1 53-158, 1 70, 1 7 1 , 1 75, 1 83, 1 88-1 9 1 , 200, 201 , 207, 2 1 1 , 2 1 3, 2 1 5 , 2 1 7, 2 1 9, 221 , 225, 227, 228, 231 , 233, 235, 240, 24 1 , 243, 246, 249-251 , 253, 257, 268, 269 thermal insulation composite system -> 1 39, 1 88, 1 91 , 201 thermal resistance -> 1 32, 1 35 thermal transmittance -> 57, 58, 1 32, 1 34 , 1 54, 1 58 thermoplastic -> 62, 64, 65, 90-92, 94, 96, 1 2 1 , 1 25-127, 1 29, 1 44, 1 73, 1 81 , 1 98 thermosensitive paint -> 1 5 thermoset --> 93

279

Index of names

thick bitumen coating -> 1 4 1 . 1 42. 1 45 tile -> 48. 52. 53. 1 2 1 . 1 23. 1 24. 1 68. 1 72. 1 74. 1 76. 1 77 . 240 timber-concrete composite construc­ tion -> 1 67 timber-concrete composite floor -> 1 63. 207 timber-framed buildings -> 44. 46. 54 timber-frame construction -> 1 58 timber element floor -> 1 63. 1 65 timber joist floor -> 1 64. 1 66 titanium-zinc -> 82. 83. 1 1 4. 1 1 9. 1 3 1 TOC value -> 1 47. 1 48 tolerance -> 39 total energy transmittance -> 89 toughened safety glass -> 85. 87. 1 1 6. 1 1 9. 1 50. 205. 2 1 9. 230. 239. 255. 257. 259. 260 toxicity -> 23. 24. 1 35. 1 47. 1 92 translucency -> 1 1 . 1 3. 1 30 translucent concrete -> 1 6 transparency -> 1 1 - 1 3 . 85. 91 . 1 1 6. 1 1 8. 1 30. 1 57. 21 6. 229. 240 transparent thermal insulation -> 86. 1 36. 1 40 trass -> 48. 1 90. 204 triple glazing -> 89 tubular particleboard (ET) -> 74. 1 59 tunnel -> 49. 50. 63. 237 two-part coating -> 1 93-195 two-way-span intermediate floors -> 1 63. 1 64

U U-value -> 1 9. 5 1 . 88. 89. 1 1 5-1 1 7. 1 32. 1 34. 1 40 ultraviolet radiation -> 1 5. 62-64. 86. 89. 91 . 92. 1 09. 1 1 5. 1 23. 1 25. 1 26. 1 28. 1 29. 1 37. 1 38. 1 43. 1 84. 1 93. 1 94. 1 971 99 un bonded screed -> 1 71 unburned (sun-dried) bricks -> 47. 1 55 uncoated PTFE cloth -> 1 30 undercoat -> 63. 65. 1 4 1 . 1 45. 1 89-1 91 . 1 94. 1 98. 1 99. 2 1 8. 243. 254 underfloor heating -> 39. 1 39. 1 72. 1 76. 1 77. 1 83. 1 84. 21 1 unplasticised PVC -> 94. 1 47 . 1 50 untreated timber -> 1 0 upside-down roof -> 1 25. 1 26 V vacuum insulation panel (VIP) -> 1 33. 1 36 vapour barrier -> 64. 1 1 4 . 1 20. 1 25. 1 31 . 1 35. 1 45. 207. 2 1 1 . 2 1 3. 2 1 5. 221 . 227. 228. 235. 24 1 . 246. 253 vapour permeability -> 55. 1 35. 1 45. 1 53. 1 89. 1 90. 1 95 varnishes -> 1 92. 1 95. 269 vault -> 1 22 vaulting -> 38. 48. 54. 1 62 vegetable fibres -> 46. 1 83 veneer -> 61 . 7 1 -75. 1 07, 1 09. 1 1 0. 1 1 9. 1 58-1 61 . 1 67-169. 2 1 1 . 2 1 4 , 2 1 7. 227 ventilated cavity -> 1 07-1 1 1 . 1 1 6. 1 1 8. 1 1 9. 240. 241 . 249. 257 ventilation -> 23. 25. 26. 1 05. 1 07. 1 1 0. 1 1 1 . 1 1 4. 1 20. 1 22. 1 24. 1 32. 1 33. 1 42. 1 46. 1 50. 1 66. 1 67. 1 97 . 205. 207 . 2 1 4. 2 1 6. 221 . 245. 250. 254. 255 ventilation cavity -> 1 20. 205. 221 . 245. 250 verge -> 52. 1 22 vinyl wallpaper -> 201 volatile organic compounds -> 26. 268. 269 volatile substances -> 23. 26. 1 94 vulcanisation -> 90-92 W waffle slab -> 1 62-164 wallpaper -> 27. 38. 86. 1 45. 1 57. 1 82. 1 88. 1 99-201 warm deck -> 1 20

280

waste water -> 26. 59. 94. 96. 1 43. 1 46. 1 47 . 1 49. 1 50 water-repellent coatings -> 1 99 water/cement ratio -> 56 waterproofing -> 1 5. 26. 63-65. 72. 81 . 83. 90. 92-96. 1 05. 1 20. 1 2 1 . 1 25-128. 1 30. 1 31 . 1 34-137. 1 39. 1 4 1 . 1 42. 1 44. 1 45. 1 70. 1 72. 1 88. 205. 207. 209. 2 1 1 . 2 1 3. 2 1 5. 22 1 . 227. 231 . 24 1 . 243. 249. 253. 257. 269 waterstop -> 1 1 3. 1 44 water absorption -> 39. 4 1 . 49. 5 1 . 53. 60. 6 1 . 1 35-137. 1 88. 1 89. 1 91 . 1 96. 1 97 water permeability -> 1 96 water vapour diffusion -> 63. 1 42. 1 45. 1 88. 1 95. 1 96 wearing course -> 57. 1 20. 1 70. 1 72. 1 73. 1 78, 1 79 weathering steel -> 77. 78. 1 04. 1 1 4, 1 1 5. 232. 233 weather resistance -> 63 welding -> 78. 79. 81 . 90. 94. 1 20. 1 2 1 . 1 27. 1 50. 1 69 white cement -> 56. 59 window -> 1 1 , 1 3. 27. 73. 78. 79. 83. 89. 93. 94. 1 08. 1 1 7. 1 43. 1 57. 207. 209-2 1 1 . 2 1 3. 2 1 5. 2 1 8. 2 1 9. 221 . 241 . 243. 244. 246. 248-251 . 253. 257. 259. 260 wind loads -> 1 52. 1 62. 1 91 . 237 wind suction -> 1 1 4. 1 23. 1 25-1 27 wired glass -> 85. 86. 1 1 6. 230 wood-based product -> 73. 74. 1 59. 1 78 wood-block flooring -> 1 76-179. 1 84. 1 85. 207. 2 1 0. 249. 269 wood-wool multi-ply board (WN-C) -> 1 36 wood-wool slab (WN) -> 1 36 wooden floorboards -> 1 66. 1 74 . 1 85 wooden shakes and shingles -> 1 09. 1 22 wood fibre insulating board (WF) -> 1 36. 1 45 wood preservatives -> 75. 268. 269 wool -> 27. 56. 57. 72. 86. 1 28. 1 32-139. 1 4 1 , 1 61 . 1 68. 1 69. 1 75. 1 83-1 85. 1 90. 1 9 1 . 207. 2 1 9. 249 workmanship -> 25. 27. 7 1 . 1 1 2 . 1 42. 1 48. 1 49, 1 51 . 1 54. 1 59. 1 66 y

yield point

-> 77. 78

Z zinc -> 24. 77. 78. 81 -83. 1 01 . 1 1 4. 1 1 9. 1 2 1 . 1 24. 1 3 1 . 1 47-1 49. 1 93. 1 97 zinc alloys -> 82

Index of names A Aalto. Alvar -> 53 Ackermann + Raff -> 1 95 Ackermann & Partner -> 66. 1 30 Allmann Sattler Wappner -> 240. 241 Anderegg. Ruben -> 2 1 8. 2 1 9 Ando Architecture Design Office -> 229-231 Ando. Tadao -> 58. 59 Architektengemeinschaft Marschwegstadion -> 1 29 Architektengruppe Stuttgart (Lohrer. Pfeil. Bosch. Herrmann. Keck) -> 1 56 Arets. Wiel -> 1 56 Arte Charpentier (+ Abbes Tahir) -> 222. 223 ASP Schweger + Partner -> 261 -263 Aspd in. Joseph -> 54 Assmann Salomon & Scheidt -> 256. 257 Asymptote -> 1 93 Auer + Weber -> 1 66

B b & k + -> 92 Barragan. Luis -> 1 86 Baumschlager Eberle -> 66 Bearth + Deplazes -> 1 55 Behnisch + Partner -> 87. 90. 1 06 Behrens. Peter -> 48. 1 55 Belidor. Bernard Forest -> 54 Bendimerad. Sabri -> 245 Betrix & Consolascio -> 1 93 Bicheroux. Max -> 84 Bienefeld. Heinz -> 5 1 Blandini. Lucio - > 96 Bolles & Wilson -> 1 58 Burham. Daniel -> 78 C Calatrava. Santiago -> 57 Caminada. Gion -> 1 97 Charreau. Pierre -> 84 Cheret & Bozic -> 1 58 Chombart de Lauwe. Pascal -> 245-247 Christo & Jeanne-Claude -> 1 52 Claessen Koivisto Rune -> 60 Col burn. Irving -> 84 Cruz Ovalle. Jose -> 1 66 Cullinan. Edward -> 226-228

o

Delugan + Meissl -> 1 20 Design Antenna -> 87 Dieste. Eladio -> 48 Dietz Joppien -> 251 -253

N NIO -> 224. 225 Nio. Maurice -> 1 6 N L architects - > 1 4. 1 5 NOX (Lars Spuybroek) 234

p

-> 59

Palladio. Andrea -> 1 04 Pawson. John -> 1 98 Perraudin. Gilles -> 208. 209 Perrault. Dominique -> 1 40 Perret. Auguste -> 54 Piano. Renzo -> 83. 38 Pilkington. Alastair -> 84

R

-> 54

H Haring. Hugo -> 1 04 Hascher Jehle -> 237-239 Hasenauer. Karl Freiherr von -> 1 66 Haus-Rucker-Co -> 90 Hegger Hegger Schleiff -> 48. 95. 1 1 8 Herzog & de Meuron -> 34. 60. 83. 1 06. 1 30 Hild & K -> 1 55 Holzmeister. Clemens -> 204 Ibos + Vitart -> 248 Ibos. Jean Marc -> 248-250 Ikeda. Masahiro -> 232. 233

J Johnson. Phi l i p -> 84 Jourda + Perraudin -> 1 1 8 Jourda. Franc;oise -> 1 97 . 208. 209 Joy. Rick -> 44. 1 06. 1 55 K Kahn. Louis -> 54. 1 65 Karl + Probst -> 1 65 Klotz. Matthias -> 1 65 Klumpp. Hans -> 1 89 Koolhaas. Rem -> 1 4. 1 1 5 Korteknie & Stuhlmacher -> 75 Kraemer & Sieverts -> 1 66

M MADA s.p.a.m. -> 2 1 2 . 2 1 3 Mansilla y Tunon - > 1 62 Marin + Trottin -> 1 95 Marquardt Architekten -> 84 Marte.Marte -> 204. 205 Mayer H .. Jurgen -> 1 4. 1 5. 81 Meier. Richard -> 1 60 Mies van der Rohe. Ludwig -> 62. 83. 84. 1 58. 1 8 Ming Pei. leoh - > 88 MVRDV -> 53. 254. 255

Olbrich. Joseph Maria -> 76 Olgiati. Valerio -> 1 89 Otto. Frei -> 90. 95

F Formalhaut -> 1 04 Fourcault. Emile -> 84 Fueg. Franz -> 38 Funhoff. Dirk -> 28 Future Systems -> 2 1 4. 2 1 5 G Garcia-Abril. Anton -> 95 Gaztelu. Jaime (Ana Fernandez) Gehry. Frank -> 83. 1 4 . 1 68 Gigon + Guyer ->8 1 . 84. 1 58 Gobbe. Emile -> 84 Graft -> 1 81 Grand. Pascal -> 1 29 Grimshaw. Nicholas -> 76 Gropius. Waiter -> 84

-> 229

o

E Eliasson. Olafur -> 44 EM2N (Mathias Muller. Daniel Niggli) Esslinger. Marc -> 32

Kuma. Kengo

L Lacaton & Vassal -> 90. 2 1 6. 2 1 7 Lainer. Rudiger - > 1 89 Larsen. Henning -> 41 Le Corbusier -> 54. 57. 1 86. 1 95 Longhena. Baldassare -> 1 75 Loos. Adolf -> 1 22. 38 Losonczi. Aron -> 1 7

Reitermann + Sassenroth -> 46 Riegler Riewe -> 242 Rogers. Richard -> 81 Rubio. Justo Garcia -> 57 Ruch. Hans-Jiirg -> 206. 207 Rudolphi. Alexander -> 22 S Sauer. Christiane -> 1 4 Sauerbruch Hutton Architekten -> 1 1 6. 1 66. 258-260 Schultes. Axel -> 58 Semper. Gottfried -> 1 66 Snozzi + Vacchini -> 220. 221 Sobek. Werner -> 88. 96 Splitterwerk -> 95 Staab. Volker -> 1 55 Steiger. Peter -> 1 8 Suuronen. Matti -> 96

T Tahir. Abbes -> 222. 223 Team Extasia -> 95 Tectone (Sabri Bendimerad and Pascal Chombart de Lauwe) -> 245-247 Tezuka. Takaharu & Yui -> 232. 233 Trucco. Jacomo Matteo -> 54 U Ungers. Simon -> 2 1 0. 21 1 Utzon. J0rn -> 48. 53 V Vitart. Myrto

-> 248

W Wandel Hoefer Lorch Hirsch -> 59. 83 Wright. Frank Lloyd -> 54. 1 09. 1 1 3 Wulf & Partner -> 1 56

Z Zumthor. Peter -> 87. 1 55 Zuuk. Rene van -> 1 22

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