Prefabrication is back, and the steel frame is once again making a positive contribution to fast-track housebuilding
Despite the fact that in the past the UK was at the forefront of developments in innovative housebuilding techniques, steel housing has consistently failed to gain a foothold in the market. With a new generation of architects trying it out, will it be different this time around?
Steel systems are riding the Eganfuelled wave of interest in prefab, and their current high profile is backed by a decade of research by Corus and the Steel Construction Institute.
The £35 million Oakridge Central Regeneration project, which will provide 300 units of steel-framed, low-rise housing, is currently on site, and the next phase of the Greenwich Millennium Village will utilise an innovative, site-rolled, steel-frame system. The proponents of steel frame are making a vociferous case for it to be considered as an alternative to both timber frame and masonry.
The construction industry is often accused of having a short memory. In the current excitement it would be easy to forget that steel housing in the UK has a long and undistinguished history. Some 150,000 steel houses have been built in the UK, but this volume has only been achieved through periods of frenzied activity followed by decidedly lean times. A 1987 report by the BRE listed 85 different steelframed and clad systems developed in the previous 70 years. However, only about 15 of these had been used to produce more than 1,000 houses, and only a handful were in production for more than a decade.
Few systems have achieved a commercially viable volume of production, and most have remained as costly prototypes. So what makes Corus, and those other investors in the 10 or so new systems that have come to market in the past decade, believe that they will fare any better?
A quick trawl through the history books might be advisable for anyone who thinks that marrying steel with UK housebuilding will be easy.
Any old iron
Iron houses were developed in Britain from the 1840s onwards for export to the colonies, where they overcame a lack of materials and skilled labour.
These systems were often designed and promoted by leading industrialists, concerned with opening up new markets for their iron products. An acceptable aesthetic for housing in the UK, though, was never developed, and iron came to be viewed as a material suited only for industrial applications and the casting of ornate decorative components. Equally importantly, the export of houses to the colonies was brought to an end by the development of local production facilities and a scarcity of iron caused by the Crimean War.
In the period after the First World War, the pattern of future attempts at metal housing in Britain can be summarised by the on-and-off backing by industrial concerns whose core business lay outside housebuilding; the failure to appeal to British taste; and an association with emergency housing.
That 'homes fit for heroes' period, which intended that 500,000 extra houses be built, was cut under the 'Geddes Axe' (Sir Eric, not Sir Patrick) of 1921-22, in order to reduce spending and alleviate Britain's spiralling inflation. Even so, at least 15 different steel systems were proposed, and about 23,000 steel houses built.
Of particular interest is the Weir house, promoted by industrialist and wartime air minister Lord Weir.
Using factory fabrication, Weir proposed to reduce site work and use cheap labour from the Glaswegian shipbuilding industry. The first of a planned series of factories was set up at Cardonald in Glasgow, with an intended weekly output of 60 houses.
However, Weir's proposals met with fierce opposition from the construction industry, which threatened to halt work on local authority housing schemes in protest. In two years of production, Weir built just 1,552 houses.
Weir houses were intended to be a temporary solution and, externally clad in steel plate with expressed joints, they had an obvious prefabricated aesthetic. The houses suffered from technical deficiencies, for example, extensive rusting of the cladding plates which caused them to buckle and bulge in an unsightly fashion.
The Dorlonco house, developed during the same period, was a more successful product. More than 10,000 were built to a design that conformed to the contemporary Neo-Georgian local authority style, with an external finish of brick or render. The steel frame was supplied and erected by the Dorman Long Company, but other work was carried out by the established construction industry.
The end of the 1920s 'homes fit for heroes' plan illustrates another common problem for UK steel-frame housing. Marketed as temporary local authority housing, take up of the systems by the private housebuilding sector was extremely limited. When political and economic changes led to a reduction in public sector housebuilding, steel-frame house production came to a virtual standstill.
Only when post-war conditions prevailed again in the 1940s was steel housing given another chance. The technical shortcomings of earlier steel houses were perhaps glossed over to absorb the over capacity of the steel industry. The lessons of the earlier period were not learnt, and over-ambitious production targets, technical problems and the curse of the temporary housing label also plagued steel housing of the 1940s.
During the 1945-51 period, about 100,000 steel houses were built, including 41,000 Arcon prefab bungalows and 36,000 British Iron and Steel Federation (BISF) houses.While the Arcon is a case study in prefabricated methods, the BISF house was a model attempt to produce a popular, permanent, high steel content house.
Designed by Sir Frederick Gibberd, the BISF was technically and aesthetically competent, but unchallenging when compared with other proposals of the time. Junctions between components were dealt with in an understated fashion, traditional finishes could be incorporated or simulated and construction used tried-and-tested methods. Despite its popularity, even the BISF was unable to survive the end of the housing crisis and upheaval in the steel industry, including nationalisation in 1951.
Systems, systems It took another housing crisis, this time caused by a lack of production in the private sector, to bring about the next wave of steel housing in the 1960s. Ambitious targets for house production were set, and to local authority architects the success of the steel frame CLASP school building system indicated the way forward.
More than 50 steel housebuilding methods - from both public and private sectors - are listed in various systems compendia of the time, although only about 15 went into production. The demise of these systems followed a wider disillusionment with prefabrication; though there were undoubtedly technical failures, steel was only implicated indirectly in the backlash against the high-rise concrete systems.
Continuity in technical and architectural development was once again cut short, and there was a hiatus in steel frame housing until British Steel, with an interest in increasing the market for its strip products, launched the SureBuild system in 1993.
Today, steel frame has been tipped as the one to watch among the rivals to brick and block construction. Have the lessons been learnt from a centuryand-a-half of iron and steel housing?
Technically, the case seems to be a good one. Technology has caught up with ambition, particularly in the understanding of moisture movement within structures, and the Steel Construction Institute has published a comprehensive series of technical and design guides.
The Light Steel Frame Group of established producers, aware of the risk should a flawed system come to the market, will be keen to ensure that emerging methods are sound. This vigilance bodes well, but the temptation will be strong to push the boundaries ofknowledge and experience, particularly when it comes to reducing cost.
Reliance on large production runs, a downfall of many previous systems, has been reduced by the introduction of low-cost rolling mills. At Greenwich Millennium Village these have been used by contractor PowerWall to produce panels on site, a low-volume production method that allows for variation in panel design and reduces transport. Although this seems to suggest a less than universal approach to housing, it certainly has its place.
As with the Dorlonco house of the 1920s, the SureBuild steel frame has been designed to disappear into a conventional brick skin. This stealthy approach has at least persuaded some major housebuilders to give the system a try, and more architecturally interesting examples are now beginning to emerge, such as Allford Hall Monaghan Morris' Raine's Dairy housing for the Peabody Trust, and Hunt Thompson Architects' work at Oakridge Central.
The private housing market will be important if steel frame is to survive future changes in the steel industry and political policy; changes that history would suggest are inevitable. A stable market is required for effective innovation of systems and processes, and with demand high, it would seem likely that the private sector will continue its 30-year pattern of steady output. The needs and preconceptions of the end user must be better understood if steel frame is to emerge from behind the Tudorbethan cladding and be effectively marketed on its merits.
The potential advantages of steel frame are diminished by an external skin of traditional brick, but it will take some time to develop alternatives that will appeal to the speculative housebuilders. The cost case will also need to be more convincingly made, so that switching to steel frame is clearly shown to be worthwhile in an industry focused on short-term profit.
Proponents of steel frame need to keep one eye on the past, one on the future and both feet firmly on the ground. As history suggests, cracking the housing market will not be easy.
Tom Hughes is a PhD student at the department of architecture, Nottingham University.
E-mail Tom@2hd.co. uk or visit www. tsav. demon. co. uk