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Prefabricated Systems

Principles of Construction

These titles have also been published in this series: Maarten Meijs, Ulrich Knaack Components and Connections – Principles of Construction ISBN 978-3-7643-8669-6 Ulrich Knaack, Tillmann Klein, Marcel Bilow, Thomas Auer Façades – Principles of Construction ISBN 978-3-7643-7962-9 Prefabricated Systems

Principles of Construction

Ulrich Knaack Sharon Chung-Klatte Reinhard Hasselbach

Birkhäuser

Building with prefabricated systems encompasses the production and use of pre-planned components or modules as a solution to build with higher quality and more efficiency. It is associated with dimensional grids, high technical standards, lower costs and the repetition of components or objects. Today, almost every science and industry is systemised, and the building industry is not an exception, but rather a late bloomer. Building systems are used to simplify complex planning and constructional process-es. Their special character lies in the fact that they are not related to any specific build-ing task but can be applied as universal solutions. System building is often referred to as prefabricated systems because of the industrial nature of construction production. Many building systems consist of manufactured components and use industrial meth-ods of assembly, even when constructed on site.

The term system building must also be seen in the context of a time horizon. The first systematisations applied to the smallest units: bricks, which had been in use since 7500 BCE. Today’s system building is relevant to much larger and more complex com-ponents. The increasing complexity of systematisation is demonstrated by the term “module” (modulus , Latin for measure). Whereas in earlier times, module described standardised measurements or dimensions, such as the Japanese tatami mat or Le Corbusier’s mod-ulor, the term today stands for standardised components of an overall system. And the components can be further broken down into separate elements. In the last century, visionary experiments in building systems enjoyed public atten-tion, but the novelty of industrialisation wore off relatively quickly in architecture. The mass production of standard components is thriving, and in some sectors, such as housing, prefabrication of whole buildings is experiencing a slow restart. A one-off product is still perceived as a handcrafted work of art, and the repetitive industrialised house does not conjure up images of the beautiful home. Is it impossible to create good architectural products and repeat them hundreds of times? Or is the dream of high-quality, cost-effectively produced architecture purely an ideological posi-tion that does not work in today’s world of individualists? Is the element of prefabrica-tion reciprocal with the idea of non-permanence, or is there too much hesitance in ac-quiring a high-tech product that is larger than an automobile and lasts for longer than ten years? This leads to the question of good vs. bad architecture. Does serial production lower product value? Artists Andy Warhol and Dan Flavin based some of their works on the notion of repetition of identical everyday objects (1). The series of otherwise simple Campbell’s soup cans or the marching rhythm of fluorescent light tubes is the essence of the artists’ works. Can a repetitive built environment (2) be planned intelligently and provide the essence of architecture we are looking for? In the search for individuality and corporate identity, does mass customisation suffice in architecture?

Building systems and prefabrication

Taking a step back to the roots of the matter to inquire about the systematisation of architecture (4), we recognise that many architects and builders rely heavily on systems because the demands of the scope of the projects and the expected time of delivery cannot be met with traditional methods. Building systems include the production of building elements, whether on or off site; the subcategory prefabrication includes all systemised off-site manufacturing of components and elements (3). Among the bene-fits of successfully using systems, including prefabrication, are quicker construction on site, better ability to build to optimum cost and higher-quality end products due to closer factory control as part of the manufacturing process. From an architect’s point of view, the impact of prefabrication on architecture is positive on the one hand, because the profession consistently involves more areas of responsibility, and prefabrication allows a cumulative development of technical knowl-edge: connections, details and technical standards. On the other hand, it has a nega-tive image because it instigates a fear that intelligent thinking and creative architecture, as well as the architectural profession itself, are becoming obsolete. From the clients’ point of view, building systems have a reputation ranging from low construction stan-dards to high-end technology and are even ultimately considered fashionable. System building is generally believed to be the opposite of on-site building because the manufacturing takes place off site. It is not associated with anything organic: syste-mised building usually connotes boxy, orthogonal shapes and strict grids. The style of prefabricated systems scoffs at the sort of architecture that conjures the homemade aura, or the vernacular (of a place), since the industry and industrialised products aspire to speak a modern language (of a time). However, these generalisations are only partly correct.

On-site methods of construction, for example, stick-built houses, are often thought to be the slower, hand-made methods. In some cases, stick-built methods, have indeed become more systemised, methodically and architecturally, than prefab products on the market today. Some on-site building construction methods may be low-tech, but other on-site building procedures that parallel advanced high-efficiency production methods of the factory far exceed the production output of standard building procedures. Cases in point are Quadrant Homes of USA and Toyota Homes of Japan. Business manage-ment experts from the automobile industry who learned from each other overseas and constantly oversaw self-improvement plans are responsible for these highly efficient and successful building construction methods. Whereas Toyota Homes prefabricates the house components in the factory, the American firm produces most of the homes on site – and both produce stick-built homes at top speed and with admirable quality. Clearly, system building does not necessarily take place off site.

Housing and industrial building

This book discusses two areas of construction that could hardly be more different: residential and industrial building. These areas were selected because they already have a particularly high degree of prefabrication and comprise a large proportion of total building activity. Several factors shape the housing market: there are private clients, who favour indi-vidualisation but would still like to build cost-effectively and/or with a guarantee on price. This segment covers, among other things, prefabricated housebuilding compa-nies, which, for example, claim 14 % of the market in Germany. On the other hand, real estate companies design and develop whole new residential areas, where there is a high demand for housing, such as in the Netherlands. The industrial building category includes offices, commercial and industrial build-ings, which have to fulfil a very wide range of different requirements. On the one hand there is the inner-city office block, which has to meet the architectural and urban-plan-ning requirements and accommodate complex building services. And on the other hand, there are the factories and warehouses, which, because they are often erected on the urban periphery, have to satisfy much reduced needs for architectural expression and building services. The architectural quality that can be achieved with preplanning and prefabrication must therefore be considered with respect to the particular project. With prefabrication can come loss of local typology, construction methods and materials. Other building types, for example stadia, can profit from a high degree of prefabrication and, as the contract sum is many times that of a single detached house, new designs can be devel-oped exploring options for prefabrication and modularisation to form a project-specific modular building system.

Today, system-built products can even assume organic shapes (5, 6, 9). Moulding of three-dimensional forms, calibrating movements and translating information for CNC machines would not be possible without CAD systems. The Geodesic Dome (Richard Buckminster Fuller, 1954), the undulating roof at Kansai airport (Renzo Piano, 1988– 1994) and the International Terminal at Waterloo Station (7) in London (Nicolas Grim-shaw, 1990–1994) were seminal projects. Greg Lynn studied the animation of forms using computer-generated models with his Embryological House in 1999. In this case, a complex organic 3D grid system was created with CAD systems. Finally, vernacular architecture, a term which conjures images of classical or tradi-tional architecture, can have different stylistic consequences in the context of systems. If vernacular architecture is understood as the architecture intrinsic to a place and to its function, it can certainly be modified to meet today’s building standards of a house in an industrialised, digitalised place for a changing nuclear family. The modified vernacu-lar architecture, as demonstrated in Vorarlberg, in the western part of Austria, is a per-fect example of this. Modern buildings are adapted to the needs of the modern family and the requirement of energy efficiency, while still using local materials. The compact and simple forms of the architecture are suitable for smaller families but blend into the traditional context of a community previously characterised by agriculture (8).

The objectives of this book are twofold: the main objective is to present to the young practitioner the current status of prefabricated building by documenting the different systems according to building typology and building components, thus systematically weaving a picture of the world of prefabricated systems. The documentation is supple-mented with photos and drawings setting a clear framework of creative processes. The second objective is to discuss the following questions: do the architect’s aims of achiev-ing individuality and artistic expression suffer from the modularising, codifying and repeti-tion associated with prefabricated or preassembled building systems? Or does the ar-chitect gain flexibility in design as the building systems offer a high standard of quality?

Following this introduction, the chapter on the history of building systems highlights a few exemplary moments in the long story of building systems. The included prefabricated systems are not necessarily the most successful or ideologically the best examples of system building. The failures and visions were as important as the commercial successes. The chapters on housing and commercial or industrial buildings document examples that delineate certain aspects, such as the different building construction methods. The chapter on housing covers the basic construction types, the extent of prefabrication and its implications on site and the issue of cultures, façades and their “cross-referenc-ing” of styles. Commercial, or non-residential buildings, make up most of the built pre-fabricated architecture. The building type is broken down into three categories: tempo-rary buildings, serial buildings and individual buildings. Modular concepts, flexibility, and construction methods are addressed here. The fifth chapter, on the procedure of manufacturing a building, covers aspects con-cerning the logistics of planning, production, transportation and the assembly of a build-ing. The efficiency of the manufacturers, their productivity, adaptability to different needs and standards are networked aspects of the building procedure. The aim is not to col-lect the latest tips on production or operation and materials of the market, but to dis-sect, display and analyse the matrix of methods and materials. The chapter on components classifies the building’s tectonics – systems, subsys-tems – and takes into account the developer’s point of view; each layer is a clear build-ing part allocated to a contractor, such as the loadbearing structure or building services. The final chapter opens a perspective on the future of prefabricated architecture. We, the authors, hope to deliver a straightforward and informative collection of facts on building systems and at the same time offer insight into typically non-tectonic issues that form the systems in the first place.

History of Building Systems

What is the essential target of building systems? The systemisa-tion of any building technology aims at producing more efficient and more cost-effective buildings than traditional methods. Sys-tems of building and the subsequent variety of architectural “Ge-stalt” took their cues from the cultures of peoples, the geogra-phy and its natural resources, technological advances and, especially, the visions of architects and engineers. Thus, pin-pointing the beginnings of building systems is quite challenging. Although developments in industrialisation, transportation and communication have internationalised the building industry to some extent, significant differences remain between countries and their attitudes toward building systems. This chapter traces the history of building systems and its path of advancements in different contexts. The mobility, flexibil-ity, security and economy achieved by various building systems are crucial to present-day better living and working conditions. At some moments in history, however, building systems offered the quickest, barely adequate shelters as a matter of survival. The examples shown in this chapter illustrate that the develop-ment of building systems did not only depend on the successes – some were expensive failures that were nevertheless important in the pursuit of architectural qualities and aspirations.

early systems

The Mongolian yurt

For over 2,000 years, nomadic tribes have been travelling in the steppe regions of Mongolia with their families and homes in the cyclic search for pastures to resource food and trade crafts. The yurts, the traditional homes of the Mongolians, are light, trans-portable and easily built (1). Made of pliable wooden worm fenc-es, woollen blankets, ropes made of yak- and horsehair and linen sheets, the yurts, also called gers, are raised and dismantled within 60 minutes and can be transported by two or three cam-els. The round form provides the maximum area for the given material, and the aerodynamic roof shape fends off the winds. The woollen blankets provide thermal insulation against temper-atures that can reach –40 °C and the outer layer of linen pro-vides protection against rain (2). The weight and size limitations of transportation by camel are clear practical criteria for the building system of yurts.

The tatami mat in Japan

The Japanese tatami mat flooring element is the revised stan dard module of common architectural measure that has been used in Asia for over 1,000 years. The tatami mats, with measurements of 6 shaku 3 sun (190 cm) by 3 shaku 1.5 sun (95 cm), are the basis upon which the spacing and sizes of the columns, sliding doors, verandas and eaves are still determined today. Slight vari-ations in size apply to different regions in Japan, but this system of building with elements as measurement modules has allowed the development of a remarkably high standard of craftsmanship and the standardisation of highly refined technical and functional details. It is important to note here that the term “module” in architec-ture refers to a standard unit of measure used to determine the size of building components. The tatami is an example (3–5), as is the shaku (30.3 cm), the 1.25 m module in Germany or the 2 × 4 inch (5.1 × 10.2 cm) module in the USA. Many modules and varia-tions exist, the most well-known ones being those developed by architects Leonardo da Vinci and Le Corbusier. This is not to be confused with the contemporary use of the term “module” refer-ring to fully fitted-out boxes, sometimes interlocking, which are produced as finished products for living or working in.