Title: Industrialised building. Finding a winning system
Pages: 44 - 51
Author: Terence Bendixson
Condor's Portal Frame is designed expressly for enclosing huge spaces with the minimum of obstructing columns. The basic engineering design is ruthlessly pared down and very economic. If you do not care for the details it is bad luck.
Finding a winning system
by Terence Bendixson
By far the most publicised change currently taking place in the building industry is the development of prefabricated kits of parts called 'industrialised building systems'. For some reason, these have caught the fancy of newspaper editors and hardly a month goes by without the national dailies showing the latest 'wonder building' - for which manfacturers invariably choose such names as Resicon, Trusscrete, Brownspan or some other etymological hybrid.Thisarticle,the second in a series on industrialised building,classifies the different systems in current use and describes their advantages and disadvantages.
Industrialised building systems have a long history. An early instance is the cast iron buildings that were shipped around Cape Horn to San Francisco in the 1849 gold rush. Paxton applied the same technology to the Crystal Palace, completed two years later, and by the second part of Queen Victoria's reign the idea had become sufficiently embedded in the culture for Trollope to refer quite non-commit/ally to an "iron church" in The Claverings.
By the 1930's, the growing number of car owners and gardeners living in Britain's quickly spreading suburbs (370,000 houses were built in the year ending March 1937) had called into being a new industry making primitively systematic garages and sheds, mostly in timber. After the second world war came prefabs, the least successful being made of aluminium in aircraftfactories on a swords-into-ploughshares basis, the more durable (which are with us still) having a broader technological base.
As I pointed out in the first article in this series (DESIGN 196/34-38), the development of systems is not the essence of building industrialisation, it is merely the result of applying scientific method to one part of the building process. The application of the same attitude to architectural design (the use of standard details and network analysis, for instance) and to the analysis of the building user's needs (sociology and ergonomics) is just as important.
This article will, however, primarily be concerned with building systems, and an effort will be made to sort them out. From a designer's point of view, one distinction immediately becomes apparent. A large number of systems are based on the exploitation of a single material, a completely different approach from those that are based on the analysis of human or social needs. Into the former category falI Alcoa's House of the Future, I C I's Plastics Developmen t House, The Steel Company of Wales and Richard Thomas & Baldwin's Ibis system, and the Wall Frame system by Bison Ltd (a subsidiary of Concrete Ltd). In all cases, the promoters were already in business as producers of a particular material and were searching around for new markets. (This is also the background to the French heavy concrete panel systems - Balancy, Coignet, Costa magna and so on. They were the outcome of a surplus of investment capital among cement producers.)
The user based systems are those such as CLASP, SCOLA, Wimpey No-Fines, Nenk (to be discussed in detail in a later article) and the Ministry of Housing's 5M and 12M systems. They show no evidence of any special effort to use one particular material. The criteria of selection have been cost and appropriateness to need. At the risk of treading on professional toes, there seem to be grounds for saying that the former is an engineer's approach, the resolution of a problem by proceeding on a narrow front, while the latter is an architect's approach, an attempt to synthesise all the factors affecting the problem.
Two other classifications that can be applied to building systems are function and the material of the main structure (which is at present generally concrete, steel or wood). Judging by the recently published Industrial Building Systems Annual 1965 (D ESI GN 199/68), the three most importantfunctions for which systems have been designed are schools, factories and housing. In some cases, the school systems also have more general applications as office buildings. This adaptability stems from the need to have a structure capable of forming spaces as different in size as gymnasia, class- rooms and staff of fices. At the same time, it must be usable up to several storeys and massive enough to provide good acoustic insulation between teaching rooms. It is debatable whether any single existing system meets all these requirements as well as does the skilful use of traditional techniques. Even the Ministry of Public Building and Works' Nenk, which was designed to meet a very broad brief - all the types of shelter required in a military barracks, a community with probably more diverse needs than a small town of comparable size - is not yet considered comparable with traditional construction. As Roger Walters and Ralph Iredale of the ministry's Directorate of Research and Development (which produced Nenk) said in their paper to the Royal Institute of British Architects, "We have a long way to go before architects can choose industrialised techniques for their economy in time and resources, and yet have the freedom of choice they really want"
The post war 'prefabs' represented an important experiment in the industrialisation of building. They were years ahead of their time in providing an integral approach to the fabric of the building and the fittings which went inside - an achievement which is seldom emulated in the housing systems currently available.
One of the many heavy concrete panel building systems available in Britain. This is a French development. Of particular interest are the storage walls. Four of these can be seen, complete with slots to take shelves. Also visible are the walls with plumbing runs and ventilation ducts cast into them. Holland and Hammer and Cubitts Ltd. the British licencees for Balancy, say that the walls and floors can be arranged to suit any layout. Following in the footsteps of Nottinghamshire, with its CLASP school building system, came a second consortium of local authorities called SCOLA, led by Shropshire. This is one of the first buildings to result Walberton and Binsted Primary School, built by West Sussex County architects department. All the window walls can be seen to have a rail at thigh height which protects the glass and provides a fixing for furniture. It can be seen in use in the interior photograph.
Prototype of a heavy concrete panel house designed by the London County Council architects department in conjunction with Taylor Woodrow Anglian Ltd. Concentration on systems for flats on the Continent has made it necessary for British architects and contractors to prod ace indigenous house systems. This one has concrete cross walls and gable ends with timber facade panels.
Choosing a system The reason for selecting industrial building systems in preference to traditional construction tends therefore to be because one factor, such as a shortage of time or of skilled labour dominates the contract, or because the people involved desire to experiment withoutany prompting from Government or the professions. Factory buildings, on the other hand, because of their comparatively simple nature, have been very widely systematised. When the brief is to build large uncluttered production areas as quickly as possible, prefabricated portal frames in steel or prestressed concrete are commercially very attractive (aesthetically, they include some of the best and worst examples of system building in the country).
However, two very distinct approaches are apparent in this field. In Britain, the tendency is toward stock structural solutions such as those in the Arcon or Condor catalogues. In the United States, on the other hand, a few designers and manufacturers seem to have reached a further stage in the development of an industrialised building philosophy. The designer designs a one-off solution of ruthlessly simple specification, and the suppliers to the building industry use the tremendous flexibility of modern machine tools to meet this demand for purpose-made buildings. A British example of this approach is the works of the Cummins Engine Co at Darlington, County Durham, designed by Eero Saarinen and Associates. It is a huge, flat roofed steel structure built up of standard sections. Its walls consist of no more than panes of tinted glass set into full height mullions with rubber gaskets. In Britain, this tailor-made approach to prefabricated construction has become common only in the pre-cast concrete wall panels of of flee buildings. These can now be ordered economically in virtually any shape, size or section required.
Exploded view of a system designed by Fry, Drew & Partners in conjunction with Barry High Ltd. The structure is entirely precast concrete, some of the panels being cast with a decoration resembling a folded curtain.
One of the most heavily backed systems in the country is John Laing's Jesperson, based on Danish technology. At present three fully automated plants are in prod action or under construction. The system is based on 4 ft wide four panels of variable span within 1 ft multiples. The wall units were originally made in three sizes but this is now being red aced to two, 4 ft and 8 ft wide. A typical structure/ plan is shown, rig kit, with its adaptation into a three room flat with non-structural partitions. A drawing of wall unit types complete with electric circuits is a/so shown, below right. The photographs are of the prototype Jesperson house in a re-development sponsored by the Ministry of Housing and Local Government at St Mary's, Oldham, Lancs.
It is, however, in the field of housing that the greatest hopes are generally held out for building systems in this country. This is not a rational hope - it is prompted by knowledge of a pressing need. The existence of powerful local authorities with large housing programmes, and in some cases consortia of them, as well as quasi Governmental agencies, such as new town development corporations, should provide the sure and steady market that a heavy capitalised industry needs. Hitherto, however, such factors as the low wages paid to building craftsmen, local authority contracts that offer no incentive to speed and productivity, and a Ministry of Housing and Local Government grant system that is not geared to the need for five year housing programmes, have all militated against the adoption of building systems. Now there are signs that these limitations are beginning to be recognised and that something may be done about them. What has been done Butthis should not conceal what has already been achieved. To take just three examples: Wimpey has built 125,000 dwellings using its primitive No Fines technology (concrete made with gravel alone, instead of sand and gravel); Laing has built 80,000 with Easiform in situ concrete cavity wall method; and, by far the most sophisticated, Bison has built or is building nearly 6,000 flats in over 100 blocks with its prefabricated Wall Frame system.
One additional reason for the slow adoption of systems in Britain is the widespread popularity of houses as opposed to flats. Houses are not intrinsically harder to systematise, but are affected by some special external factors. For instance, site irregularities, whether of contour or shape, often make a variety of house types desirable. Furthermore, there are difficulties in moving heavy components over soft ground. Tower cranes are useless because their working distance is quickly exceeded. However, progress is now being made in two directions. On the one hand, groups such as the Midlands Housing Consortium and the Yorkshire Development Group are using traditional materials within a strictly modular discipline. On the other, full prefabrication of houses is being got under way by the Ministry of Public Building and Works at Aldershot and by Livingstone Development Corporation near Edinburgh using Laing's AM Jesperson system. At the same time, the London County Council/Greater London Council expanded towns division is using the Taylor Woodrow Anglian systems (based on Larsen and Nielsen's Danish technique) at Haverhill in West Suffolk.
One way of industrialising building is to transfer work from the site to a factory. This has probably been taken further in Britain by Truscon Ltd than by any other firm in the heavy concrete field. Maisonettes are made up of 10 boxes of two sizes. All plumbing, wiring, painting and glazing are finished at the factory. An experimental block has been built in Manchester.
A lot of thought and effort has been given in some places to simplifying and speeding up traditional building methods. One example is the Mactrad house designed jointly by John Maclean of Wolverhampton, contractors, and the Timber Research and Development Association. The result is a marriage of prefabricated timber wall panels and roof trusses with brick veneer. Brick is used only for its excellent weathering qualities and in a cross wall because of its ability to block noise,
Five approaches to housing
In fact, a great variety of new technological-cum-economic approaches to housing construction is in evidence, and it is anyone's guess which will prove the most successful. Arthur Ling (former city architect and planning officer at Coventry and now Professorof Architecture and Civic Design at Nottingham University) has identified five major categories:
1 On-site mechanisation ranging from the use of cranes, fork-lift trucks and pumped cement to electric hammers. Such tools can equally well be applied to bricks and mortar construction as to prefabricated systems.
2 On-site factory production of medium sized elements such as Wates Ltd's technique for casting concrete wall and floor panels of various sizes in adjustable steel moulds. Ideally, such a production line is rayed down on what subsequently becomes one of the site service roads. The Building Research Station battery casting system being experimentally used at Edmonton, London, is another example of this approach. Wall panels are cast vertically in moulds that consist of an earlier batch of panels (experiments aimed at reducing the amount of jointing between panels are being done at the same time).
3 Off-site production of small and generally light weight elements, as in CLASP and SCOLA. Both consist of steel frame structures with timber carcassing to which a wide variety of facing materials such as tiles, lapped boarding and asbestos siding can be fixed. Both these systems are primarily for school construction as theirlightness is not well suited to housing.
4 Off-site production of medium sized elements. One example is the Bison Wall Frame system, a British development for multi-storey flats involving pre-cast, load-bearing concrete floorand wall members. Laing's 12M Jesperson system, a Danish technique, has been tailored to British requirements in collaboration with the Ministry of Housing, and permits a high level of architectural freedom in planning and appearance. The factories are highly mechanised.
5 Off-site factory production of whole rooms. This approach has been most thoroughly developed in the Soviet Union and is the least flexible of all methods from the point of view of both design and construction. The architect has to fit all the necessary functions into rigidly fixed boxes measuring perhaps 20ft long x9ft wide Deft high. The contractor is committed to using very powerful cranes running on tracks capable of turning only in large radii. Truscon Ltd is experimenting with a modified version of this approach in Britain.
The need for interchangeability The purpose of this article has been to show the variety of systems on the market and the differences in their philosophy. There is a positive jungle. Compared with the even calm that prevailed in the industry while the brick was king, this chaos is a setback. However, it is likely that a new order will grow out of the present confusion. The promoters of several systems, official and commercial, are emphatic that development must now proceed toward dimensions and joints that permit interchangeability. The Ministry of Public Building and Works' bulletins on dimensional co-ordination are one step in this direction. Economic pressures on the promoters of commercial systems are likely to support such a trend. To survive in a competitive market and get a return on their capital, private firms will need to sell every component they possibly can. One way of doing this is to supply them, not in packages as part of closed systems, but as enlarged bricks. A builder might then get concrete gable and cross wall panels from one maker, floor slabs from a second, and timber front and rear elevation panels from a third. Efforts to achieve this sort of interchangeability and its consequences for the furniture, household appliance and other industries will be discussed in some future articles in the series.
One of the contributions of the Building Research Station to improving building technique is the Humper. It can do the work of a fork lift truck, and carry and tip wet concrete. It is at present being made under licence.
Bison's Wall Frame system has been more widely used than any other method of building high flats on the market in Britain. The exploded drawing shows its simplicity. Judging by the appearance of the buildings completed, the result can be either pleasing or beastly depending on the skill of the architect.
A way of getting speedier building is to set up a factory on site. Wates Lid does this using large steel moulds to cast concrete panels. A development by the Building Research Station dispenses with steel moulds and uses concrete panels. Casting is done vertically. Starting with a mother and father panel, a child is cast between them. These are opened out and another cast between them, and so on.