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Service core units and prefabricated bathrooms in industrialized building
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Paper 10
SfB (74) U DC 643.521 Service core units and prefabricated bathrooms in industrialized building Miss J. M. A. Shepherd,
DIP ARCH, ARIBA
Service core units were first used in Britain just after the Second World War. Since that time several plastics prefabricated bathrooms and several service core units have been developed. Although these units are technically possible there are factors which do not make them a practical proposition in the United Kingdom at the moment. These barriers could be broken down in the near future, but until then units will have to be made from materials which require smaller production runs to be economic.
FIG 1 The Brabazon airliner (Courtesy John Laing & Son Ltd)
The Brabazon I was a lumbering monster of the air, the conception of which marked the end of a war, a war which had rendered people homeless at the rate of 250000 a year, a war which on ending meant that many men and women who had been engaged in the production of weapons would now be without work. In April 1944 the report was published of an interdepartmental committee on House Construction under the chairmanship of Sir. G. Burt. This committee had looked into the possibilities of using standardized windows, baths, water heaters, and cisterns. As a result of its findings it recommended amongst other things the 'temporary houses'. A prototype known as the Portal House was built to illustrate what was required. In 1944 executives, engineers and metallurgists from the aircraft and aluminium industries also met to discuss the mass production of houses. They developed an aluminium house, which complied with principles laid down in the Portal House, and built a mock-up. In October 1944 the then Minister of Aircraft Production, the Rt. Hon. Sir Stafford Cripps, instructed the Bristol Aeroplane Company to build a prototype house. In June 1945 the Minister of Works, Mr. Duncan Sandys, announced that the Government had
F I G 2 View of assembled aluminium unit (Courtesy Development Association)
Aluminium
ordered 50000 of these houses, and later the order was increased to 54000. Several other types of temporary houses were developed, and a total of 124 970 temporary houses were erected between 1945 and December 1949,
Miss Shepherd is with John Laing Research and Development Limited, Boreham Wood, Herts.
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Miss J. M. A. SHEPHERD
and each house contained a standard heart unit regardless of the type. This was only possible because of the large orders placed directly with the manufacturing firms by the Government, and of the Government's insistence that all temporary houses should conform to a given plan (see FIG 2).
(a) Interior
(b) Complete unit FIG 3 Dymaxion bathroom unit (Courtesy Buckminster Fuller)
Before the end of the war one man in America, Buckminster Fuller, also saw the need to convert the War Aircraft Industry to more peaceful activities. In 1945 the Beech Aircraft plant in Wichita, Kansas, produced a prototype of a more advanced version of Fuller's Dymaxion House, which had been developed in the 1930's. This house contained a prefabricated bathroom unit, the components of which were simultaneously die-pressed from sheet steel, together with a unit containing heating, refrigeration, waste disposal and ventilation equipment. These units were far more advanced in design than their British counterparts (see FIG 3). It was proposed that there should be an annual production run of 500000 dwellings a year; the Beech Aircraft Company alone could have produced 60000, at a selling price equivalent to £1320, or £2313 for a limited production run. Although 3700 orders were placed, the end of the war brought a reduction of capital investment in the aircraft industry and toolingup funds could not be raised. This shows quite clearly the necessity for large orders of the type placed by the British Government with the Bristol Aeroplane Company in order to make factory-produced houses and units a reality. After the erection of temporary houses ceased in 1950, the use of the heart unit died out in Britain. The erection of permanent houses of non-traditional construction was still being encouraged, and in the Housing Manual of 1949 the following appeared: 'the development and application of new methods
should not be confined solely to the shell of the house. Important economies in time, labour and cost could be effected by the préfabrication of internal parts, and fittings to fit a shell of standard size, whether in brick or other forms of construction.' Some firms did try to fit prefabricated units into non-traditional houses, but, generally speaking, it did not prove successful. This was partly because the non-traditional houses did not use industrialized building techniques in the true sense of the word, and partly because skilled labour was still easily obtainable on sites. The urgency for housing was also becoming less. Thus the need for heart units, prefabricated plumbing and the like became less. For the next ten years préfabrication for housing was almost forgotten about, although it was still used for school buildings. Architects, the author amongst them, tended to regard préfabrication as an academic exercise. A bathroom consisting of several free-standing units placed on a wooden floor seemed always rather illogical. The heart unit of the temporary houses did nothing to overcome these difficulties. The junctions between the lavatory basin, bath, floor and walls were still awkward. The mastic used to fill some joints hardened and fell out, and large gaps were left where the profile of the prefabricated unit did not match up with that of the wall. Water was often splashed from the basin and the bath on to the wooden floor and eventually caused it to rot. Need this have been so ? Why should not the bathroom as a whole have been regarded as one unit for the cleansing of the
SERVICE CORE UNITS AND PREFABRICATED BATHROOMS IN INDUSTRIALIZED BUILDING
human body? And why could not water have been poured and emptied into this unit? It could have had a hollow part where only a small quantity of water was needed and another larger hollow in which one could stand and pour water over oneself or lie down in the water. The floor of the bathroom itself could have been a large tray, with a spongy covering on which to stand, and an outlet in the corner for the water to drain away. The walls could have been heated so that they were warm to lean against instead of icy cold. How could such a unit have been made from one sheet of material, so that it was watertight? And from what sort of material could it have been made ? At that time the great wealth of plastics materials which are now available had not been developed, and moulding techniques had not been fully developed for those that were available. Aircraft canopies, trays and various other articles having been made from acrylic sheet, it did not seem impossible that a bathroom could have been formed from such a material. Despite not fully understanding the techniques of moulding acrylic on a large scale the author produced a design in 1954 for a house using a prefabricated unit in acrylic for the lower half of the bathroom. This design was gradually amended and added to until, probably as a result of an illustration of Buckminster Fuller's bathroom, the idea was incorporated of having a top half as well as a bottom half to the unit, and a bathroom of this type was incorporated in a design for a house in 1957-58 (see FIG 4). These designs were all very much of an academic nature, but by 1961 the need for préfabrication was again arising. There was already a shortage of skilled bricklayers and plasterers. Higher pay and better conditions in factories did not encourage young men to take up the long apprenticeships needed to become skilled craftsmen, and to work on cold, wet and muddy building sites. Although the labour force of the building industry was increasing by about 1 per cent per annum, this increase was almost entirely unskilled. The need to develop new building techniques had become apparent. At the same time the plastics industry was developing very quickly and was turning to the building industry as a possible outlet for its materials. One of the largest plastics raw-material manufacturers in the country decided that this was the right moment to build a house to demonstrate how plastics could be used to provide some of the new building techniques within the next few years, and asked one of the largest building organizations to design and build the house for them. This exercise provided an opportunity to experiment with a prefabricated bathroom in plastics. Since plastics have a low l v a l u e compared with such materials as the structural metals, they can be used economically for structural applications only in forms such as shells. A bathroom unit moulded in two halves makes full use of the shell form, and for this reason it was decided to use a prefabricated bathroom of this type in the house. The problem now was the choice of material. For various reasons J-in-thick pvc sheet was chosen as the structural material, reinforced with sprayed poly-
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urethane foam; the bath and lavatory basin were to be of acrylic, and the wc pan of ceramic. The choice of pvc, in fact, presented certain design limitations, since the maximum size of sheet which could be obtained for use in this experiment was 6 x 4 ft. This immediately ruled out the possibility of forming the bathroom in two mouldings, and so a compromise was reached. The bathroom was formed from pvc trays cemented and welded together. Since acrylic has a different coefficient of expansion from that of pvc, the bath and lavatory basin had to be built into the bathroom in such a way that they were free to move independently of the bathroom itself. The lavatory basin was fairly easy to accommodate by fixing it with a flexible joint into a hole left in the structure, but the accommodation of the bath was not so easy. In order to keep the continuity of the structure under the bath, the acrylic bath was formed as a liner within a pvc bath which actually formed part of the structure. The acrylic liner was left free to move, being attached to the structure with a flexible joint. When the pvc structure had been assembled, the plumbing and the electric wiring were fixed. The hot and cold water pipes were in polypropylene, and the waste pipes in pvc. The whole structure was placed on a flat metal sub-frame, which was necessary to enable the unit to be lifted, and then sprayed with poly urethane foam 1 in thick. The completed unit was then moved from the factory to the house and slid into
position ( F I G S 5 and 6).
The experiment proved that a self-supporting structure could be made in thin thermoplastic material, without the need to use a shell structure, and that no framework was needed to support it, despite the fact that the design was criticized in some journals for not making the best use of plastics. On seeing illustrations of prefabricated plastics bathroom units from the Continent, in which the bath and lavatory basin have formed part of the structure, several local authority housing managers have been worried by what might happen in the case of breakages. The success of forming one bath within another showed that it would be possible to form an easily removable liner to the structure which could be replaced in the event of damage. The success of this bathroom unit led the plastics manufacturers to go a stage further and develop a prefabricated bathroom and service core in which two large acrylic mouldings, reinforced with sprayed glass-reinforced polyester resin, were used to form the bathroom. The mouldings in this unit relied for their structural stability on stress-skin plywood panels, in the two-storey unit, or on a steel frame, when the bathroom is used as a separate unit. The actual details of this unit are the subject of another paper. The next stage in development would be to design a structural unit using plastics alone, and to incorporate the wc as part of the moulding, as well as the bath and lavatory basin. Although it is technically feasible to produce such a unit, is it in fact practical in this country at the moment?
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Miss J. M. A. SHEPHERD
-5'r
standard ba+h
oo ΐο ine of lifting | ; έ ; ^ frame , -&$%;$
I window fixed to 4^f'.·-:' ., >■'.-■::' I cladding panel-:: : . ; # * ·:> ,· : i; iv
I"' ■·
/
h#- '^ ;C^Ä
bathroom compartment
wjridö.w fixed to cfaidcftnC] panel ,
w.c. compartment
standard bath
structura Plçath γ FIG 4 Plan and section of bathroom (Courtesy John Laing & Son Ltd)
* ·:· ■;0;i:>;: .'^ ·'.··' Φ P
SERVICE CORE UNITS A N D PREFABRICATED BATHROOMS IN INDUSTRIALIZED BUILDING
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results, which were competitive in cost, and which could usefully supplement existing local labour and contracting resources. The White Paper also stated that the Government did not wish to repeat the uniformity of post-war prefabricated houses, but that industrialized building techniques should aim at producing a system which can be used to build a variety of dwelling types. By the end of 1963 the Ministry of Housing and Local Government was aware of 260 systems of industrialized building already existing or in the course of development. Since then the number has increased to about 340 systems.
FIG 5 Bathroom being slid into position in the house {Courtesy I.C.I. Plastics Div)
In May 1963 the Government published a White Paper on Housing which outlined 'the Government's proposals for expanding the provision of housing in this country and raising it to a higher all-round standard than ever before.' Although the housing position over the previous ten years had greatly improved, there were still insufficient houses. Therefore in order to keep up with growth and to provide for a steady rate of replacement the Government aimed to reach a figure of 350000 houses a year and to sustain it, instead of the figure of 270000, the average for the previous ten years. Towards the end of the year the Government raised its target to 400000 a year. The White Paper stated that the Government hoped to maintain the present growth of house building for owner occupation, and to increase the output of Local Authority housing. The increased output would depend to a large extent on the building industry, but the Government promised help by encouraging local authorities to planfiveyears ahead, and by encouraging public authorities to use systems which promised good
k.
\
FIG 6 Interior view of bathroom {Courtesy LCI. Plastics Div)
The ultimate aim of 400000 houses represents the output of approximately 30 factories producing industrialized systems, without having to impinge upon the traditional industry at all. But the systems vary greatly in the degree to which they are industrialized and in the output to which their factories are designed. For instance, in one system the factories are designed to produce 30 houses a day, and three factories have been planned together to give an annual output of over 30000 houses. In order to be competitive in cost with traditional methods, this system requires contracts for a minimum of 500 dwellings units, consisting of not more than 5 types. Another system at the other end of the scale is designed for site factory production based on an annual output of 150 houses. Only approximately 250000 houses of the total output will be for local authorities and Government departments; the other 150000 will be for owner occupation. It is highly unlikely that industrialized building will be used to any great extent for private housing. This is due to the fact that private housing sites are usually more of an infill nature, one or two houses being built on odd pieces of ground between existing building. It is only the large building contractors (who constitute only 0-6 per cent of the total number of firms) who can afford to buy a site of any size and develop it, and it will only be the largest of these who will be in a position to apply industrialized techniques. In order to cope with the demands for buildings of all types during the next ten years the building industry will have to increase its output by 50 per cent. It has already increased its output by 47 per cent during the last ten years, but since the annual increase in labour is not keeping pace with the required increase in output ( 1 - 2 per cent compared with 7 per cent) the building industry cannot cope unless the fullest use is made of industrialized building techniques. It cannot afford to have 340 different systems for housing alone; it can only afford to have so many systems that when the factories are working at full capacity they produce the numbers of houses required annually. It cannot afford to have any factories working at half capacity. The systems use different materials and different methods of construction and are based on different modules. For instance, of the two systems looked at by the Research and Development Group of the Ministry of Housing one is a lightweight and largely factory-produced system called '5 M'.It is substantially based on dimensions of 5 times a 4-in module, and
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Miss J. M. A. SHEPHERD
the other a concrete panel system of building called '12 M' (dimensions 12 times a 4-in module). Is it possible for an independent manufacturer to design a prefabricated bathroom or a heart unit to suit all these different systems ? Generally speaking, it is essential to design such units for the system in mind; occasionally it is possible to use the same unit for systems of similar type. It is possible to design a traditional house around such a unit. Some systems will be able to make use of a completely prefabricated unit, whereas other systems will require a partially prefabricated unit. Some systems will be able to make use of two-storey units; others will be able to use only single-storey units. Even with one system, there are still going to be variations if the system is to be as flexible as the Government would prefer. The system has to be capable of building houses, maisonettes, and flats as well as being suitable for all aspects of any type of site. In the Parker Morris Report, three recommendations were made for combinations of bathrooms and wc's: 3-person families 1 wc, which may be combined with the bathroom. 4-person families and 5-person families in one-level dwellings 1 wc separate from bathroom 5-person and larger families in 2- or 3storey houses or in 1 wc combined with bathroom two-level maisonettes and 1 wc separate 6-person and larger families in one-level 1 wc combined with bathroom dwellings and 1 wc separate. This gives at least two variations in design to start with: a bathroom with wc combined, and wc with lavatory basin. These two alone are not really sufficient, since it would unnecessarily increase the area of the house in some cases, and so it is advisable to have four variations - a bathroom without wc, a bathroom with wc, a wc, and a wc with lavatory basin. Further variations result from the requirement that some will have to be left-handed and some right-handed, giving a total number of seven variations. Further minor variations occur in the plumbing due to variations in height of the building. The Government is hoping that many of the systems will be of a non-proprietary nature, and that they will be available to all firms capable of using them; this also means that architects will be able to plan the houses and flats to their own designs, provided they use the standard components. There is a large number of architects who tend to design the outside of the house first and then fit the rooms in as best they can, and the bathrooms and kitchens invariably end up in whatever corner is left. This results in bathrooms being anything but standard. On looking through thirty plans of houses all designed by architects, one noted some twenty-five variations in plan. This sort of architect is not accustomed to using prefabricated components ; no-one had ever taught him
how to. If he cannot design in his usual manner using the prefabricated components he will discard them and resort to traditional methods. Bathroom units and service cores will be the first to be regarded with suspicion, since their use demands a different design process from that to which he has been accustomed. Such architects are not going to help in the standardization of components, and will tend to increase the variations which already exist. In December 1963, the National Building Agency was set up to advise local authorities on how to organize their building demands into large contracts planned as far ahead as possible by forming themselves into consortia, and to help them to choose and use industrialized building methods. The Agency is there only to advise; it cannot instruct local authorities to use a particular system or to join a consortium. The local authority is free to choose for itself. Therefore, it can be seen that there are three factors in this country at the moment which are not conducive to the use of prefabricated components using large plastics mouldings : 1 The large number of industrialized housing systems (340), which makes it impossible for all of them to be used to their fullest advantage. 2 The variations which are required owing to basic planning requirements. 3 The inability of many architects to design for industrialized building. These factors do not make it possible to guarantee production runs long enough to pay off high tooling cost. Whilst these conditions exist, bathrooms and service cores can be prefabricated only provided they are made up of components which can be joined together in a variety of ways to give the required flexibility in layout and the varying degrees of préfabrication required by differing systems of construction. It is not possible to use plastics for the main structure of such units in these circumstances, since plastics in sheet form are too expensive compared with traditional materials. (A traditional bathroom, complete and ready to hand over to the client, costs £115 for houses and walk-up blocks of flats, and £155 for multi-storey work. These prices are for a bathroom 5 ft 8 in x 6 ft 8in ; this includes all the finishes and dry partitioning to two walls, but these account for only £35 of the total cost). Apart from lack of standardization, there is one difficulty which plastics have to overcome before their use is freely accepted by local authorities. Local authority housing is paid for over a period of sixty years, and a local authority will expect any house it builds still to be in a habitable condition at the end of that time. A local authority, on being offered a plastics bathroom unit as part of a system of building, is naturally going to query its durability. The authority will want to know what will happen when the tenant accidentally leaves a lighted cigarette on the edge of the bath on the first day. It will want to know what happens when the handyman of the house drops the hammer in the bath and cracks it. Can it be repaired
SERVICE CORE UNITS AND PREFABRICATED BATHROOMS IN INDUSTRIALIZED BUILDING
or does the whole unit have to be replaced ? Until all these questions and many more like them can be answered to the satisfaction of the local authority, it will not be willing to use plastics components. Enough work has now been completed to show that it is technically possible to produce prefabricated bathrooms and service cores in large numbers, but certain things are still required to make them practical : 1 Insistence by the Government on the use of standardized plans for heart units so that the same unit can be used in a variety of systems. 2 Some directive from the Government as to which of the many systems of industrialized building should be the ones to use, and the alteration of housing subsidies to ensure that they are used to their best advantage. 3 Instruction to architectural students how to design correctly using prefabricated components, instead of concentration so much on one-off jobs, as is done at present. 4 Provision of post-graduate courses in the use of industrialized building for those architects who are already qualified.
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Unfortunately industrialized building techniques flourish better under a dictatorship than under a democracy, and the United Kingdom is a democratic country. Bibliography
'The First Factory-Made Bungalow'. Aluminium Development Ass. Housing (Temporary Accommodation) Act. 1944. H.M.S.O. Housing (Temporary Accommodation) Act 1945. H.M.S.O. Housing (Temporary Accommodation) Act 1947. H.M.S.O. The Housing Manual 1949. Ministry of Health. The Housing Act 1961. H.M.S.O. 'Homes for today and tomorrow'. Ministry of Housing and Local Government. White Paper 'Housing' May 1963. H.M.S.O. White Paper Ά National Building Agency' December 1963. H.M.S.O. Report of the Ministry of Housing and Local Govt. 1963. H.M.S.O. Housing Return for England and Wales 30 September 1964. H.M.S.O. Design Magazine, No. 184. April 1964. 'Packaged Bathrooms'. Architectural Design July 1961. 'Plastics in Building - A Full-Scale Experiment'. Architects Journal 28 August 1963.
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Discussion on Papers 9 and 10 M R . D . BULLIVANT
(Architect)
It should be noted that in the past the term 'service core' was used to mean different things, including (a) central ducts with certain fixtures (sanitary, heating and hot-water) attached, and (b) whole rooms with floors and ceilings complete in themselves and containing ducts and services. These two papers relate to the development of the latter kind, which give certain advantages and disadvantages, and pose difficult problems for manufacturers. Advantages and disadvantages The acceptance of innovations depends on the advantages to be gained, so that it is worth thinking hard what these are. The advantages may be enumerated as follows : 1. Saving in site labour by removing many time-consuming operations from the site. This means fewer man-hours per dwelling unit. 2. Reduction in period of building by removing a complex group of operations which are difficult to co-ordinate on site. The period required will be shortened perhaps considerably. This could lead to savings in the total cost of the building. 3. Improved room design and standard of trouble-free services due to more intensive design and testing in the factory. The disadvantages are the restriction on planning freedom for the architect and the need for the contractor to programme delivery and installation of all units carefully. Both can be overcome when contracts are for large numbers of dwelling units. Problems in manufacture The development will require careful costing, and a 'value engineering' approach is necessary. With present techniques 50-60 per cent of the cost of the service core will go in services in heating, plumbing and electrical installations, and without a radically different technical approach the components used will be the same as those used on site, but they are assembled under high-overhead conditions. How can this be done economically ? As the manufacturer is closely affecting the design of the whole building he must be prepared to give guidance and technical service to architects and contractors. From the marketing point of view there are problems of product definitions and product mix and of how to fit in with so many different building systems. How is the design-planning flexibility which architects demand to be provided? M R . T. RIDLEY
The paper by Mr Kirby and Mr MacLeod is the first to describe the 'design' approach to using plastics for familiar objects in a building. The 'free-shape' which has been adopted for the service core unit is presumably derived from the use of special moulded forms used in the manufacture of the plastics material. I should like to ask Mr. Kirby, as the architect-designer concerned, if he could say more about his experience with this unit, from the design point of view. In having to solve the problem of function and user appeal, and also to take account of a new material and manufacturing processes, he would appear to have achieved a very satisfactory unit of design. Could he also say something about corners? If the use of plastics involves designing mostly with continuous surface forms, the question of corner shapes must need to be critical in design and planning. M R . KIRBY (in reply)
The fundamental basis of the design approach was complete co-operation between designer and production team. All the members of the team co-operated in each other's work. The designer started by considering the initial specification and the user requirements in relation to his first tentative ideas on the shape of the finished object. The producing team started with considerations of moulded possibilities. The real point of fusion was in fact the mould-making and in this the work finally resolved itself in the hands of the master craftsman responsible for mouldmaking. This can be related to the second part of Mr. Ridley's question. Our initial ideas, and our initial technology too, were both fairly simple and we kept to very large-radius corners and a broad treatment of the scheme in order to simplify our vacuum
moulding. We now know that at many points we could have much sharper angles, although it would not be possible to achieve knife edges. Corner design is critical in the use of plastics since corners represent concentrations of stresses in the material both in the moulding and in use, and a lot more needs to be known in this area. This is not to say, however, that all corners should be completely rounded as they were in our first bathroom. In many plastics techniques—particularly the more precise processes of extrusion and injection moulding—and also in the assembly of stressed skin panels one can consider sharp angles and shapes of high complexity. I do not consider that the sweeping 'egg form', so often suggested as essential to plastics, is the only answer; it is, however, a very good simple starting point until one has become more competent in handling the materials both from the design point of view and from the technology point of view. M R . T. C. PEARSON (RolinxLtd, Manchester) Will Mr. Kirby give some amplification of the development of heart units through smaller sub-units for bathrooms and kitchens ? M R . KIRBY (in reply)
Smaller sub-units for kitchens and bathrooms require more joints and more labour to assemble. On the other hand, they require less massive capital equipment and they do enable greater variation of arrangement to be provided. The problem is therefore one equating a selected production process to the costs of larger or smaller units on a production line. In the case of vacuum-formed units, joints are comparatively difficult to make, and it is therefore easier to fabricate the large one-piece moulding. Where production runs would tolerate an injection-moulding process, joints would become easy but production runs necessarily high. There is no simple single reply to this point and one can only make the best choice possible from the large number of variable factors. M R . D . EMBLING {Ministry of Housing and Local
Government)
The Government should not insist or direct as suggested by Miss Shepherd, but through consortium work and the N B A should persuade and convince. Miss SHEPHERD (in reply) Mr. Embling's comment that the Government should not 'insist' or 'direct', but through consortium work and N B A persuade and convince, does not make sense. At the moment there are some three hundred building systems, all different from one another. If all these systems are going to be used, then they cannot operate efficiently since there are insufficient houses required a year. Therefore some of these systems must fall by the wayside and become unproductive, either because the firm promoting the system has an inefficient selling organization or because the system itself has been poorly developed. One of the major disadvantages with the systems in their present form is that they are completely self-contained, with the result that manufacturers of cladding panels, windows, partitions etc are having to develop a series of specials for each individual system, and it is largely a matter of luck whether they have chosen to support a system that is going to be a success or not. A large amount of time and energy could have been saved if the Government had done one of two things: it could have developed a series of systems for itself which could then be used by a contractor, or it could have suggested some form of dimensional control which allowed components to be designed in such a way that they could be used in any system. M R . A. DIPROSE
The following statement brought to a close a somewhat inconclusive discussion between Mr. Embling ( M O H L G ) and Miss Shepherd on whether the Government should select for general use a small number of particular building systems : "Perhaps a solution to the argument may be found in the general acceptance of an agreed method of modular coordination". The discussion between Mr. Embling and Miss Shepherd illustrates very clearly the urgent need for modular co-ordination. On the one hand we have some 400 building systems all purporting to be industrialized and dimensionally standardized; on the
DISCUSSION ON PAPERS 9 AND 10
other hand we have an even greater number of components and component assemblies which also purport to be industrialized and dimensionally standardized. But you can only fit the latter into a very small range of the former. Everyone is busy creating his own dimensional standards, with the end result that there is none; and one of the objectives of industrialization—long production runs—is defeated before it even gets off the ground. Quite clearly Mr. Embling is right when he says that there should be no official direction as to which building systems should be used; even if this was a viable economic and technical proposition, which I doubt, it would be intolerable and certainly lead to a disastrous effect on the architectural environment. Equally clearly, however. Miss Shepherd is not being unreasonable in expecting a sufficient degree of national standardization to enable large numbers of service core units to be installed. Flexibility is required for user requirements and standardization for production. Surely it is not beyond our wit to achieve both. Obviously, there are many technical details to be solved in relation to particular cases, but the fundamental problem (as it is in most buildings) is concerned with the dimensions of components and spaces; this is where the designer and manufacturer start—they define the product in relation to dimensions, and where the builder ends—he assembles the product in relation to dimensions. In the final analysis it does seem that some central direction is required, namely that everyone should be obliged to use the same general system of modular co-ordination. Admittedly, certain recommendations have already been made, but they are certainly not statutory; they also tend to be far too ambiguous insofar as methods of application are concerned, with the result that they are interpreted in a variety of different and incompatible ways. In Denmark and a number of other countries, a basic module of 10 cm has been officially accepted as the principal unit of size for deriving the over-all dimensions of components and building spaces. This has been generally agreed because it is realized that the use of a basic module provides the foundation for the necessary degree of standardization and also allows for the equally necessary degree of design flexibility. Why can't we do the same in this country? MR. V. BILEK {State Committee on Science and Technology, Prague) I would like to make a general commentary before proceeding to the theme of 'heart units' now under discussion. During the last ten years Czechoslovakia has given special care and attention to the industrialization of construction and has concentrated above all on the manufacture and assembly of buildings from large-size 'prefab' units. There have been built numerous plants for manufacturing those prefabs, the expenses amounting to more than 1 billion crowns
65
(Kcs). At present this potential enables the building of about 40000 flats from large-size prefabs, representing about 50 per cent of the annual flat building. In this respect Czechoslovakia holds an outstanding position all over the world, producing about 0-20m3 (7 ft3) of prefabs per inhabitant. In using these elements a 5- to 8-storeyed house may be crudely built within 15-20 days. But its finishing requires at present 5-10 times as long a period. With a view to cutting this time and to removing some difficulties in the quality of buildings, technical development in Czechoslovak construction is interested in using new materials, among which plastics take the first place. The new building materials, especially plastics, may be applied in building from two points of view. On the one hand is the simple replacement of materials used so far, with the design of the product and the technology unchanged, its mounting and assembly being incorporated into the construction work. On the other hand, there are products that allow a qualitatively better way of achieving the construction work, reflecting their technical and economic characteristics. For a better understanding of my explanation, I will instance some typical examples: (a) Water refuse (sewage) pipes in pvc, and floor covering in pvc do not essentially change anything in the design of the existing products from traditional materials, nor in technology and in the design of buildings. (b) Light sound-insulating partitions and flat heart-units allow a prefab cross system of dwelling houses, up to 6-0 m (~ 20 feet) and eventually 7-2 m ( ^ 24 feet) which is clearly reflected in the technology of building and in the technical and economical parameters. It is indisputable that plastics are and will be in future used for products of both categories, but we are of the opinion that their full technical and economical application is linked to the second view of the conception, that is, essentially to the industrialization of building. It also holds good for the other modern building materials. In that respect we are greatly interested in international cooperation and the business that may develop therefrom. One of the developments in the use of plastics that proceeded farthest in Czechoslovakia, and which is closely connected with the existing plans for the industrialization of construction but at the same time establishes a new advance, is the flat heart-unit. Its development and production has been running for several years now, and about 53000 units are being produced, but in my explanations I shall refer only to the modern one of which about 10000 units are manufactured per year. The flat heartunit measures 2-15 x 1-66 m (85 x 65 in) and consists of two parts—a bathroom and a wc. The method of construction is shown schematically in FIGURE A. Both parts of the heart unit have their own ceiling and floor sections and a skeleton of | BYTCHEJACRO\ 8-3/A-Qt~\
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FIG A. Structural arrangement
VÛSV PRAUA
66
DISCUSSION ON PAPERS 9 AND 10
FIG B. Kitchen centre, attached to the heart unit but conveyed and delivered separately
steel members so that, with the partitions, they form a complete closed cell. The ceiling and floor sections are made of glassfibre-reinforced plastics. The partitions of 5 cm (2 in) thickness are of sandwich construction, the outer layer being formed of cellular material (Umacart) and the inner core of foamed polystyrene, pvc or paper honeycomb. The total weight of the heart unit is about 370 kg (815 lb), more than one half of this weight being accounted for by plastics. A different arrangement of both sections, together with a different position of the door, according to the requirements of the contractor offer the possibility of a series of disposition variations. All sanitary fixtures, electric installations and ventilation are incorporated in the heart unit, which is delivered as a space prefab with baths, wash basins and wc already installed at the factory. At present the units are transported to the building sites by rail, but their transportation by special road conveyors is being planned. The heart unit is assembled in the building simultaneously with the crude construction, or later, even after the whole construction has been finished, according to the type of the building. The mounting of the heart unit and the joining of the vertical installations is performed by a 4-man team in 6-7 hr. The heart unit is manufactured by Kovona (national enterprise) on a partly mechanized line, which makes its price of about 5000 Kcs rather low. The production time of the line, including testing of installations, is about 8 min. It is estimated that within the next five years the production will rise about 6-7 times. In conclusion, two views, FIGS B and c, are included to give a better idea of the Czechoslovak heart unit. M R . A . E . MOULD (Architect)
FIG c. General view of heart unit
In view of the general feeling that these materials are not being given fair and due consideration, which seems to be held by many of those who promote the use of plastics in building, it might be helpful for you to have the views of a development architect whosefieldof activity is that of local authority housing. Designers are unlikely to use a new material or even a new technique unless it can show some advantage or at least no disadvantage. Clearly, the widespread use of plastics in building is restricted because of disadvantage. One knows of factors such as low melting point and creep, but the most important factor is cost, particularly in low-cost housing. In this sector of the industry, in which a minimum building life of 60 years is required, durability and maintenance are of prime interest too, especially in the case of external surfaces. In the Midlands Housing Consortium standard house designs, plastics have been used but only in certain areas. These are: 1. External gutters and rainwater pipes, 2. Internal waste pipes, 3. Kitchen worktops (melamine), and 4. Floor tiles in thermoplastics. In these instances there seems to be advantage, or at least a reasonable expectation of advantage, in using plastics products.
Paper 10
SfB (74) U DC 643.521 Service core units and prefabricated bathrooms in industrialized building Miss J. M. A. Shepherd,
DIP ARCH, ARIBA
Service core units were first used in Britain just after the Second World War. Since that time several plastics prefabricated bathrooms and several service core units have been developed. Although these units are technically possible there are factors which do not make them a practical proposition in the United Kingdom at the moment. These barriers could be broken down in the near future, but until then units will have to be made from materials which require smaller production runs to be economic.
FIG 1 The Brabazon airliner (Courtesy John Laing & Son Ltd)
The Brabazon I was a lumbering monster of the air, the conception of which marked the end of a war, a war which had rendered people homeless at the rate of 250000 a year, a war which on ending meant that many men and women who had been engaged in the production of weapons would now be without work. In April 1944 the report was published of an interdepartmental committee on House Construction under the chairmanship of Sir. G. Burt. This committee had looked into the possibilities of using standardized windows, baths, water heaters, and cisterns. As a result of its findings it recommended amongst other things the 'temporary houses'. A prototype known as the Portal House was built to illustrate what was required. In 1944 executives, engineers and metallurgists from the aircraft and aluminium industries also met to discuss the mass production of houses. They developed an aluminium house, which complied with principles laid down in the Portal House, and built a mock-up. In October 1944 the then Minister of Aircraft Production, the Rt. Hon. Sir Stafford Cripps, instructed the Bristol Aeroplane Company to build a prototype house. In June 1945 the Minister of Works, Mr. Duncan Sandys, announced that the Government had
F I G 2 View of assembled aluminium unit (Courtesy Development Association)
Aluminium
ordered 50000 of these houses, and later the order was increased to 54000. Several other types of temporary houses were developed, and a total of 124 970 temporary houses were erected between 1945 and December 1949,
Miss Shepherd is with John Laing Research and Development Limited, Boreham Wood, Herts.
58
Miss J. M. A. SHEPHERD
and each house contained a standard heart unit regardless of the type. This was only possible because of the large orders placed directly with the manufacturing firms by the Government, and of the Government's insistence that all temporary houses should conform to a given plan (see FIG 2).
(a) Interior
(b) Complete unit FIG 3 Dymaxion bathroom unit (Courtesy Buckminster Fuller)
Before the end of the war one man in America, Buckminster Fuller, also saw the need to convert the War Aircraft Industry to more peaceful activities. In 1945 the Beech Aircraft plant in Wichita, Kansas, produced a prototype of a more advanced version of Fuller's Dymaxion House, which had been developed in the 1930's. This house contained a prefabricated bathroom unit, the components of which were simultaneously die-pressed from sheet steel, together with a unit containing heating, refrigeration, waste disposal and ventilation equipment. These units were far more advanced in design than their British counterparts (see FIG 3). It was proposed that there should be an annual production run of 500000 dwellings a year; the Beech Aircraft Company alone could have produced 60000, at a selling price equivalent to £1320, or £2313 for a limited production run. Although 3700 orders were placed, the end of the war brought a reduction of capital investment in the aircraft industry and toolingup funds could not be raised. This shows quite clearly the necessity for large orders of the type placed by the British Government with the Bristol Aeroplane Company in order to make factory-produced houses and units a reality. After the erection of temporary houses ceased in 1950, the use of the heart unit died out in Britain. The erection of permanent houses of non-traditional construction was still being encouraged, and in the Housing Manual of 1949 the following appeared: 'the development and application of new methods
should not be confined solely to the shell of the house. Important economies in time, labour and cost could be effected by the préfabrication of internal parts, and fittings to fit a shell of standard size, whether in brick or other forms of construction.' Some firms did try to fit prefabricated units into non-traditional houses, but, generally speaking, it did not prove successful. This was partly because the non-traditional houses did not use industrialized building techniques in the true sense of the word, and partly because skilled labour was still easily obtainable on sites. The urgency for housing was also becoming less. Thus the need for heart units, prefabricated plumbing and the like became less. For the next ten years préfabrication for housing was almost forgotten about, although it was still used for school buildings. Architects, the author amongst them, tended to regard préfabrication as an academic exercise. A bathroom consisting of several free-standing units placed on a wooden floor seemed always rather illogical. The heart unit of the temporary houses did nothing to overcome these difficulties. The junctions between the lavatory basin, bath, floor and walls were still awkward. The mastic used to fill some joints hardened and fell out, and large gaps were left where the profile of the prefabricated unit did not match up with that of the wall. Water was often splashed from the basin and the bath on to the wooden floor and eventually caused it to rot. Need this have been so ? Why should not the bathroom as a whole have been regarded as one unit for the cleansing of the
SERVICE CORE UNITS AND PREFABRICATED BATHROOMS IN INDUSTRIALIZED BUILDING
human body? And why could not water have been poured and emptied into this unit? It could have had a hollow part where only a small quantity of water was needed and another larger hollow in which one could stand and pour water over oneself or lie down in the water. The floor of the bathroom itself could have been a large tray, with a spongy covering on which to stand, and an outlet in the corner for the water to drain away. The walls could have been heated so that they were warm to lean against instead of icy cold. How could such a unit have been made from one sheet of material, so that it was watertight? And from what sort of material could it have been made ? At that time the great wealth of plastics materials which are now available had not been developed, and moulding techniques had not been fully developed for those that were available. Aircraft canopies, trays and various other articles having been made from acrylic sheet, it did not seem impossible that a bathroom could have been formed from such a material. Despite not fully understanding the techniques of moulding acrylic on a large scale the author produced a design in 1954 for a house using a prefabricated unit in acrylic for the lower half of the bathroom. This design was gradually amended and added to until, probably as a result of an illustration of Buckminster Fuller's bathroom, the idea was incorporated of having a top half as well as a bottom half to the unit, and a bathroom of this type was incorporated in a design for a house in 1957-58 (see FIG 4). These designs were all very much of an academic nature, but by 1961 the need for préfabrication was again arising. There was already a shortage of skilled bricklayers and plasterers. Higher pay and better conditions in factories did not encourage young men to take up the long apprenticeships needed to become skilled craftsmen, and to work on cold, wet and muddy building sites. Although the labour force of the building industry was increasing by about 1 per cent per annum, this increase was almost entirely unskilled. The need to develop new building techniques had become apparent. At the same time the plastics industry was developing very quickly and was turning to the building industry as a possible outlet for its materials. One of the largest plastics raw-material manufacturers in the country decided that this was the right moment to build a house to demonstrate how plastics could be used to provide some of the new building techniques within the next few years, and asked one of the largest building organizations to design and build the house for them. This exercise provided an opportunity to experiment with a prefabricated bathroom in plastics. Since plastics have a low l v a l u e compared with such materials as the structural metals, they can be used economically for structural applications only in forms such as shells. A bathroom unit moulded in two halves makes full use of the shell form, and for this reason it was decided to use a prefabricated bathroom of this type in the house. The problem now was the choice of material. For various reasons J-in-thick pvc sheet was chosen as the structural material, reinforced with sprayed poly-
59
urethane foam; the bath and lavatory basin were to be of acrylic, and the wc pan of ceramic. The choice of pvc, in fact, presented certain design limitations, since the maximum size of sheet which could be obtained for use in this experiment was 6 x 4 ft. This immediately ruled out the possibility of forming the bathroom in two mouldings, and so a compromise was reached. The bathroom was formed from pvc trays cemented and welded together. Since acrylic has a different coefficient of expansion from that of pvc, the bath and lavatory basin had to be built into the bathroom in such a way that they were free to move independently of the bathroom itself. The lavatory basin was fairly easy to accommodate by fixing it with a flexible joint into a hole left in the structure, but the accommodation of the bath was not so easy. In order to keep the continuity of the structure under the bath, the acrylic bath was formed as a liner within a pvc bath which actually formed part of the structure. The acrylic liner was left free to move, being attached to the structure with a flexible joint. When the pvc structure had been assembled, the plumbing and the electric wiring were fixed. The hot and cold water pipes were in polypropylene, and the waste pipes in pvc. The whole structure was placed on a flat metal sub-frame, which was necessary to enable the unit to be lifted, and then sprayed with poly urethane foam 1 in thick. The completed unit was then moved from the factory to the house and slid into
position ( F I G S 5 and 6).
The experiment proved that a self-supporting structure could be made in thin thermoplastic material, without the need to use a shell structure, and that no framework was needed to support it, despite the fact that the design was criticized in some journals for not making the best use of plastics. On seeing illustrations of prefabricated plastics bathroom units from the Continent, in which the bath and lavatory basin have formed part of the structure, several local authority housing managers have been worried by what might happen in the case of breakages. The success of forming one bath within another showed that it would be possible to form an easily removable liner to the structure which could be replaced in the event of damage. The success of this bathroom unit led the plastics manufacturers to go a stage further and develop a prefabricated bathroom and service core in which two large acrylic mouldings, reinforced with sprayed glass-reinforced polyester resin, were used to form the bathroom. The mouldings in this unit relied for their structural stability on stress-skin plywood panels, in the two-storey unit, or on a steel frame, when the bathroom is used as a separate unit. The actual details of this unit are the subject of another paper. The next stage in development would be to design a structural unit using plastics alone, and to incorporate the wc as part of the moulding, as well as the bath and lavatory basin. Although it is technically feasible to produce such a unit, is it in fact practical in this country at the moment?
60
Miss J. M. A. SHEPHERD
-5'r
standard ba+h
oo ΐο ine of lifting | ; έ ; ^ frame , -&$%;$
I window fixed to 4^f'.·-:' ., >■'.-■::' I cladding panel-:: : . ; # * ·:> ,· : i; iv
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w.c. compartment
standard bath
structura Plçath γ FIG 4 Plan and section of bathroom (Courtesy John Laing & Son Ltd)
* ·:· ■;0;i:>;: .'^ ·'.··' Φ P
SERVICE CORE UNITS A N D PREFABRICATED BATHROOMS IN INDUSTRIALIZED BUILDING
61
results, which were competitive in cost, and which could usefully supplement existing local labour and contracting resources. The White Paper also stated that the Government did not wish to repeat the uniformity of post-war prefabricated houses, but that industrialized building techniques should aim at producing a system which can be used to build a variety of dwelling types. By the end of 1963 the Ministry of Housing and Local Government was aware of 260 systems of industrialized building already existing or in the course of development. Since then the number has increased to about 340 systems.
FIG 5 Bathroom being slid into position in the house {Courtesy I.C.I. Plastics Div)
In May 1963 the Government published a White Paper on Housing which outlined 'the Government's proposals for expanding the provision of housing in this country and raising it to a higher all-round standard than ever before.' Although the housing position over the previous ten years had greatly improved, there were still insufficient houses. Therefore in order to keep up with growth and to provide for a steady rate of replacement the Government aimed to reach a figure of 350000 houses a year and to sustain it, instead of the figure of 270000, the average for the previous ten years. Towards the end of the year the Government raised its target to 400000 a year. The White Paper stated that the Government hoped to maintain the present growth of house building for owner occupation, and to increase the output of Local Authority housing. The increased output would depend to a large extent on the building industry, but the Government promised help by encouraging local authorities to planfiveyears ahead, and by encouraging public authorities to use systems which promised good
k.
\
FIG 6 Interior view of bathroom {Courtesy LCI. Plastics Div)
The ultimate aim of 400000 houses represents the output of approximately 30 factories producing industrialized systems, without having to impinge upon the traditional industry at all. But the systems vary greatly in the degree to which they are industrialized and in the output to which their factories are designed. For instance, in one system the factories are designed to produce 30 houses a day, and three factories have been planned together to give an annual output of over 30000 houses. In order to be competitive in cost with traditional methods, this system requires contracts for a minimum of 500 dwellings units, consisting of not more than 5 types. Another system at the other end of the scale is designed for site factory production based on an annual output of 150 houses. Only approximately 250000 houses of the total output will be for local authorities and Government departments; the other 150000 will be for owner occupation. It is highly unlikely that industrialized building will be used to any great extent for private housing. This is due to the fact that private housing sites are usually more of an infill nature, one or two houses being built on odd pieces of ground between existing building. It is only the large building contractors (who constitute only 0-6 per cent of the total number of firms) who can afford to buy a site of any size and develop it, and it will only be the largest of these who will be in a position to apply industrialized techniques. In order to cope with the demands for buildings of all types during the next ten years the building industry will have to increase its output by 50 per cent. It has already increased its output by 47 per cent during the last ten years, but since the annual increase in labour is not keeping pace with the required increase in output ( 1 - 2 per cent compared with 7 per cent) the building industry cannot cope unless the fullest use is made of industrialized building techniques. It cannot afford to have 340 different systems for housing alone; it can only afford to have so many systems that when the factories are working at full capacity they produce the numbers of houses required annually. It cannot afford to have any factories working at half capacity. The systems use different materials and different methods of construction and are based on different modules. For instance, of the two systems looked at by the Research and Development Group of the Ministry of Housing one is a lightweight and largely factory-produced system called '5 M'.It is substantially based on dimensions of 5 times a 4-in module, and
62
Miss J. M. A. SHEPHERD
the other a concrete panel system of building called '12 M' (dimensions 12 times a 4-in module). Is it possible for an independent manufacturer to design a prefabricated bathroom or a heart unit to suit all these different systems ? Generally speaking, it is essential to design such units for the system in mind; occasionally it is possible to use the same unit for systems of similar type. It is possible to design a traditional house around such a unit. Some systems will be able to make use of a completely prefabricated unit, whereas other systems will require a partially prefabricated unit. Some systems will be able to make use of two-storey units; others will be able to use only single-storey units. Even with one system, there are still going to be variations if the system is to be as flexible as the Government would prefer. The system has to be capable of building houses, maisonettes, and flats as well as being suitable for all aspects of any type of site. In the Parker Morris Report, three recommendations were made for combinations of bathrooms and wc's: 3-person families 1 wc, which may be combined with the bathroom. 4-person families and 5-person families in one-level dwellings 1 wc separate from bathroom 5-person and larger families in 2- or 3storey houses or in 1 wc combined with bathroom two-level maisonettes and 1 wc separate 6-person and larger families in one-level 1 wc combined with bathroom dwellings and 1 wc separate. This gives at least two variations in design to start with: a bathroom with wc combined, and wc with lavatory basin. These two alone are not really sufficient, since it would unnecessarily increase the area of the house in some cases, and so it is advisable to have four variations - a bathroom without wc, a bathroom with wc, a wc, and a wc with lavatory basin. Further variations result from the requirement that some will have to be left-handed and some right-handed, giving a total number of seven variations. Further minor variations occur in the plumbing due to variations in height of the building. The Government is hoping that many of the systems will be of a non-proprietary nature, and that they will be available to all firms capable of using them; this also means that architects will be able to plan the houses and flats to their own designs, provided they use the standard components. There is a large number of architects who tend to design the outside of the house first and then fit the rooms in as best they can, and the bathrooms and kitchens invariably end up in whatever corner is left. This results in bathrooms being anything but standard. On looking through thirty plans of houses all designed by architects, one noted some twenty-five variations in plan. This sort of architect is not accustomed to using prefabricated components ; no-one had ever taught him
how to. If he cannot design in his usual manner using the prefabricated components he will discard them and resort to traditional methods. Bathroom units and service cores will be the first to be regarded with suspicion, since their use demands a different design process from that to which he has been accustomed. Such architects are not going to help in the standardization of components, and will tend to increase the variations which already exist. In December 1963, the National Building Agency was set up to advise local authorities on how to organize their building demands into large contracts planned as far ahead as possible by forming themselves into consortia, and to help them to choose and use industrialized building methods. The Agency is there only to advise; it cannot instruct local authorities to use a particular system or to join a consortium. The local authority is free to choose for itself. Therefore, it can be seen that there are three factors in this country at the moment which are not conducive to the use of prefabricated components using large plastics mouldings : 1 The large number of industrialized housing systems (340), which makes it impossible for all of them to be used to their fullest advantage. 2 The variations which are required owing to basic planning requirements. 3 The inability of many architects to design for industrialized building. These factors do not make it possible to guarantee production runs long enough to pay off high tooling cost. Whilst these conditions exist, bathrooms and service cores can be prefabricated only provided they are made up of components which can be joined together in a variety of ways to give the required flexibility in layout and the varying degrees of préfabrication required by differing systems of construction. It is not possible to use plastics for the main structure of such units in these circumstances, since plastics in sheet form are too expensive compared with traditional materials. (A traditional bathroom, complete and ready to hand over to the client, costs £115 for houses and walk-up blocks of flats, and £155 for multi-storey work. These prices are for a bathroom 5 ft 8 in x 6 ft 8in ; this includes all the finishes and dry partitioning to two walls, but these account for only £35 of the total cost). Apart from lack of standardization, there is one difficulty which plastics have to overcome before their use is freely accepted by local authorities. Local authority housing is paid for over a period of sixty years, and a local authority will expect any house it builds still to be in a habitable condition at the end of that time. A local authority, on being offered a plastics bathroom unit as part of a system of building, is naturally going to query its durability. The authority will want to know what will happen when the tenant accidentally leaves a lighted cigarette on the edge of the bath on the first day. It will want to know what happens when the handyman of the house drops the hammer in the bath and cracks it. Can it be repaired
SERVICE CORE UNITS AND PREFABRICATED BATHROOMS IN INDUSTRIALIZED BUILDING
or does the whole unit have to be replaced ? Until all these questions and many more like them can be answered to the satisfaction of the local authority, it will not be willing to use plastics components. Enough work has now been completed to show that it is technically possible to produce prefabricated bathrooms and service cores in large numbers, but certain things are still required to make them practical : 1 Insistence by the Government on the use of standardized plans for heart units so that the same unit can be used in a variety of systems. 2 Some directive from the Government as to which of the many systems of industrialized building should be the ones to use, and the alteration of housing subsidies to ensure that they are used to their best advantage. 3 Instruction to architectural students how to design correctly using prefabricated components, instead of concentration so much on one-off jobs, as is done at present. 4 Provision of post-graduate courses in the use of industrialized building for those architects who are already qualified.
63
Unfortunately industrialized building techniques flourish better under a dictatorship than under a democracy, and the United Kingdom is a democratic country. Bibliography
'The First Factory-Made Bungalow'. Aluminium Development Ass. Housing (Temporary Accommodation) Act. 1944. H.M.S.O. Housing (Temporary Accommodation) Act 1945. H.M.S.O. Housing (Temporary Accommodation) Act 1947. H.M.S.O. The Housing Manual 1949. Ministry of Health. The Housing Act 1961. H.M.S.O. 'Homes for today and tomorrow'. Ministry of Housing and Local Government. White Paper 'Housing' May 1963. H.M.S.O. White Paper Ά National Building Agency' December 1963. H.M.S.O. Report of the Ministry of Housing and Local Govt. 1963. H.M.S.O. Housing Return for England and Wales 30 September 1964. H.M.S.O. Design Magazine, No. 184. April 1964. 'Packaged Bathrooms'. Architectural Design July 1961. 'Plastics in Building - A Full-Scale Experiment'. Architects Journal 28 August 1963.
64
Discussion on Papers 9 and 10 M R . D . BULLIVANT
(Architect)
It should be noted that in the past the term 'service core' was used to mean different things, including (a) central ducts with certain fixtures (sanitary, heating and hot-water) attached, and (b) whole rooms with floors and ceilings complete in themselves and containing ducts and services. These two papers relate to the development of the latter kind, which give certain advantages and disadvantages, and pose difficult problems for manufacturers. Advantages and disadvantages The acceptance of innovations depends on the advantages to be gained, so that it is worth thinking hard what these are. The advantages may be enumerated as follows : 1. Saving in site labour by removing many time-consuming operations from the site. This means fewer man-hours per dwelling unit. 2. Reduction in period of building by removing a complex group of operations which are difficult to co-ordinate on site. The period required will be shortened perhaps considerably. This could lead to savings in the total cost of the building. 3. Improved room design and standard of trouble-free services due to more intensive design and testing in the factory. The disadvantages are the restriction on planning freedom for the architect and the need for the contractor to programme delivery and installation of all units carefully. Both can be overcome when contracts are for large numbers of dwelling units. Problems in manufacture The development will require careful costing, and a 'value engineering' approach is necessary. With present techniques 50-60 per cent of the cost of the service core will go in services in heating, plumbing and electrical installations, and without a radically different technical approach the components used will be the same as those used on site, but they are assembled under high-overhead conditions. How can this be done economically ? As the manufacturer is closely affecting the design of the whole building he must be prepared to give guidance and technical service to architects and contractors. From the marketing point of view there are problems of product definitions and product mix and of how to fit in with so many different building systems. How is the design-planning flexibility which architects demand to be provided? M R . T. RIDLEY
The paper by Mr Kirby and Mr MacLeod is the first to describe the 'design' approach to using plastics for familiar objects in a building. The 'free-shape' which has been adopted for the service core unit is presumably derived from the use of special moulded forms used in the manufacture of the plastics material. I should like to ask Mr. Kirby, as the architect-designer concerned, if he could say more about his experience with this unit, from the design point of view. In having to solve the problem of function and user appeal, and also to take account of a new material and manufacturing processes, he would appear to have achieved a very satisfactory unit of design. Could he also say something about corners? If the use of plastics involves designing mostly with continuous surface forms, the question of corner shapes must need to be critical in design and planning. M R . KIRBY (in reply)
The fundamental basis of the design approach was complete co-operation between designer and production team. All the members of the team co-operated in each other's work. The designer started by considering the initial specification and the user requirements in relation to his first tentative ideas on the shape of the finished object. The producing team started with considerations of moulded possibilities. The real point of fusion was in fact the mould-making and in this the work finally resolved itself in the hands of the master craftsman responsible for mouldmaking. This can be related to the second part of Mr. Ridley's question. Our initial ideas, and our initial technology too, were both fairly simple and we kept to very large-radius corners and a broad treatment of the scheme in order to simplify our vacuum
moulding. We now know that at many points we could have much sharper angles, although it would not be possible to achieve knife edges. Corner design is critical in the use of plastics since corners represent concentrations of stresses in the material both in the moulding and in use, and a lot more needs to be known in this area. This is not to say, however, that all corners should be completely rounded as they were in our first bathroom. In many plastics techniques—particularly the more precise processes of extrusion and injection moulding—and also in the assembly of stressed skin panels one can consider sharp angles and shapes of high complexity. I do not consider that the sweeping 'egg form', so often suggested as essential to plastics, is the only answer; it is, however, a very good simple starting point until one has become more competent in handling the materials both from the design point of view and from the technology point of view. M R . T. C. PEARSON (RolinxLtd, Manchester) Will Mr. Kirby give some amplification of the development of heart units through smaller sub-units for bathrooms and kitchens ? M R . KIRBY (in reply)
Smaller sub-units for kitchens and bathrooms require more joints and more labour to assemble. On the other hand, they require less massive capital equipment and they do enable greater variation of arrangement to be provided. The problem is therefore one equating a selected production process to the costs of larger or smaller units on a production line. In the case of vacuum-formed units, joints are comparatively difficult to make, and it is therefore easier to fabricate the large one-piece moulding. Where production runs would tolerate an injection-moulding process, joints would become easy but production runs necessarily high. There is no simple single reply to this point and one can only make the best choice possible from the large number of variable factors. M R . D . EMBLING {Ministry of Housing and Local
Government)
The Government should not insist or direct as suggested by Miss Shepherd, but through consortium work and the N B A should persuade and convince. Miss SHEPHERD (in reply) Mr. Embling's comment that the Government should not 'insist' or 'direct', but through consortium work and N B A persuade and convince, does not make sense. At the moment there are some three hundred building systems, all different from one another. If all these systems are going to be used, then they cannot operate efficiently since there are insufficient houses required a year. Therefore some of these systems must fall by the wayside and become unproductive, either because the firm promoting the system has an inefficient selling organization or because the system itself has been poorly developed. One of the major disadvantages with the systems in their present form is that they are completely self-contained, with the result that manufacturers of cladding panels, windows, partitions etc are having to develop a series of specials for each individual system, and it is largely a matter of luck whether they have chosen to support a system that is going to be a success or not. A large amount of time and energy could have been saved if the Government had done one of two things: it could have developed a series of systems for itself which could then be used by a contractor, or it could have suggested some form of dimensional control which allowed components to be designed in such a way that they could be used in any system. M R . A. DIPROSE
The following statement brought to a close a somewhat inconclusive discussion between Mr. Embling ( M O H L G ) and Miss Shepherd on whether the Government should select for general use a small number of particular building systems : "Perhaps a solution to the argument may be found in the general acceptance of an agreed method of modular coordination". The discussion between Mr. Embling and Miss Shepherd illustrates very clearly the urgent need for modular co-ordination. On the one hand we have some 400 building systems all purporting to be industrialized and dimensionally standardized; on the
DISCUSSION ON PAPERS 9 AND 10
other hand we have an even greater number of components and component assemblies which also purport to be industrialized and dimensionally standardized. But you can only fit the latter into a very small range of the former. Everyone is busy creating his own dimensional standards, with the end result that there is none; and one of the objectives of industrialization—long production runs—is defeated before it even gets off the ground. Quite clearly Mr. Embling is right when he says that there should be no official direction as to which building systems should be used; even if this was a viable economic and technical proposition, which I doubt, it would be intolerable and certainly lead to a disastrous effect on the architectural environment. Equally clearly, however. Miss Shepherd is not being unreasonable in expecting a sufficient degree of national standardization to enable large numbers of service core units to be installed. Flexibility is required for user requirements and standardization for production. Surely it is not beyond our wit to achieve both. Obviously, there are many technical details to be solved in relation to particular cases, but the fundamental problem (as it is in most buildings) is concerned with the dimensions of components and spaces; this is where the designer and manufacturer start—they define the product in relation to dimensions, and where the builder ends—he assembles the product in relation to dimensions. In the final analysis it does seem that some central direction is required, namely that everyone should be obliged to use the same general system of modular co-ordination. Admittedly, certain recommendations have already been made, but they are certainly not statutory; they also tend to be far too ambiguous insofar as methods of application are concerned, with the result that they are interpreted in a variety of different and incompatible ways. In Denmark and a number of other countries, a basic module of 10 cm has been officially accepted as the principal unit of size for deriving the over-all dimensions of components and building spaces. This has been generally agreed because it is realized that the use of a basic module provides the foundation for the necessary degree of standardization and also allows for the equally necessary degree of design flexibility. Why can't we do the same in this country? MR. V. BILEK {State Committee on Science and Technology, Prague) I would like to make a general commentary before proceeding to the theme of 'heart units' now under discussion. During the last ten years Czechoslovakia has given special care and attention to the industrialization of construction and has concentrated above all on the manufacture and assembly of buildings from large-size 'prefab' units. There have been built numerous plants for manufacturing those prefabs, the expenses amounting to more than 1 billion crowns
65
(Kcs). At present this potential enables the building of about 40000 flats from large-size prefabs, representing about 50 per cent of the annual flat building. In this respect Czechoslovakia holds an outstanding position all over the world, producing about 0-20m3 (7 ft3) of prefabs per inhabitant. In using these elements a 5- to 8-storeyed house may be crudely built within 15-20 days. But its finishing requires at present 5-10 times as long a period. With a view to cutting this time and to removing some difficulties in the quality of buildings, technical development in Czechoslovak construction is interested in using new materials, among which plastics take the first place. The new building materials, especially plastics, may be applied in building from two points of view. On the one hand is the simple replacement of materials used so far, with the design of the product and the technology unchanged, its mounting and assembly being incorporated into the construction work. On the other hand, there are products that allow a qualitatively better way of achieving the construction work, reflecting their technical and economic characteristics. For a better understanding of my explanation, I will instance some typical examples: (a) Water refuse (sewage) pipes in pvc, and floor covering in pvc do not essentially change anything in the design of the existing products from traditional materials, nor in technology and in the design of buildings. (b) Light sound-insulating partitions and flat heart-units allow a prefab cross system of dwelling houses, up to 6-0 m (~ 20 feet) and eventually 7-2 m ( ^ 24 feet) which is clearly reflected in the technology of building and in the technical and economical parameters. It is indisputable that plastics are and will be in future used for products of both categories, but we are of the opinion that their full technical and economical application is linked to the second view of the conception, that is, essentially to the industrialization of building. It also holds good for the other modern building materials. In that respect we are greatly interested in international cooperation and the business that may develop therefrom. One of the developments in the use of plastics that proceeded farthest in Czechoslovakia, and which is closely connected with the existing plans for the industrialization of construction but at the same time establishes a new advance, is the flat heart-unit. Its development and production has been running for several years now, and about 53000 units are being produced, but in my explanations I shall refer only to the modern one of which about 10000 units are manufactured per year. The flat heartunit measures 2-15 x 1-66 m (85 x 65 in) and consists of two parts—a bathroom and a wc. The method of construction is shown schematically in FIGURE A. Both parts of the heart unit have their own ceiling and floor sections and a skeleton of | BYTCHEJACRO\ 8-3/A-Qt~\
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66
DISCUSSION ON PAPERS 9 AND 10
FIG B. Kitchen centre, attached to the heart unit but conveyed and delivered separately
steel members so that, with the partitions, they form a complete closed cell. The ceiling and floor sections are made of glassfibre-reinforced plastics. The partitions of 5 cm (2 in) thickness are of sandwich construction, the outer layer being formed of cellular material (Umacart) and the inner core of foamed polystyrene, pvc or paper honeycomb. The total weight of the heart unit is about 370 kg (815 lb), more than one half of this weight being accounted for by plastics. A different arrangement of both sections, together with a different position of the door, according to the requirements of the contractor offer the possibility of a series of disposition variations. All sanitary fixtures, electric installations and ventilation are incorporated in the heart unit, which is delivered as a space prefab with baths, wash basins and wc already installed at the factory. At present the units are transported to the building sites by rail, but their transportation by special road conveyors is being planned. The heart unit is assembled in the building simultaneously with the crude construction, or later, even after the whole construction has been finished, according to the type of the building. The mounting of the heart unit and the joining of the vertical installations is performed by a 4-man team in 6-7 hr. The heart unit is manufactured by Kovona (national enterprise) on a partly mechanized line, which makes its price of about 5000 Kcs rather low. The production time of the line, including testing of installations, is about 8 min. It is estimated that within the next five years the production will rise about 6-7 times. In conclusion, two views, FIGS B and c, are included to give a better idea of the Czechoslovak heart unit. M R . A . E . MOULD (Architect)
FIG c. General view of heart unit
In view of the general feeling that these materials are not being given fair and due consideration, which seems to be held by many of those who promote the use of plastics in building, it might be helpful for you to have the views of a development architect whosefieldof activity is that of local authority housing. Designers are unlikely to use a new material or even a new technique unless it can show some advantage or at least no disadvantage. Clearly, the widespread use of plastics in building is restricted because of disadvantage. One knows of factors such as low melting point and creep, but the most important factor is cost, particularly in low-cost housing. In this sector of the industry, in which a minimum building life of 60 years is required, durability and maintenance are of prime interest too, especially in the case of external surfaces. In the Midlands Housing Consortium standard house designs, plastics have been used but only in certain areas. These are: 1. External gutters and rainwater pipes, 2. Internal waste pipes, 3. Kitchen worktops (melamine), and 4. Floor tiles in thermoplastics. In these instances there seems to be advantage, or at least a reasonable expectation of advantage, in using plastics products.