Terrapin Ltd's prefabricated building systems are based on an absolute minimum of site work and a maximum of factory production. The above series of photographs follows the Terrapin production process from start to finish. Photographs by Anthony Weller
Architect Nick Whitehouse, managing director of the Milton Keynes factory-made building firm Terrapin Ltd, cut his teeth on prefabrication. After graduating from Sheffield, he went to work on the clasp system under Henry Swain at Nottingham, and then joined Terrapin in 1977. Today under his leadership, Terrapin builds hospitals cheaper, assembles volumetric hotels faster, and stands on the brink of launching the first ever truly modular high-rise buildings.
In the dispatching yard at Terrapin, the shrink-wrapped hotel-room pods are lined up ready to be trucked to Granada Travelodges under construction all over the country, part of an order that so far has totalled nearly 500 units. Up to 3m by 6m in size, and with their room numbers eerily already allocated, they are, as Whitehouse says, 'complete with everything except their Gideon Bibles'.
Faced with this spectacle of prefabrication in action, depending on whether you believe the precepts of the Modern Movement or not, you have either to say that Terrapin has been doing the right thing for 50 years - or that the Milton Keynes producer is still banging its head against a (literally) brick wall in its unremitting efforts to enlarge the market for factory- made buildings. The state of the company during the savage property recession of the early 1990s might have inclined observers to the latter view - but looking at Terrapin today reveals a very different picture.
Terrapin is a living history of prefabrication. Under its legendary founder, the late Harry Bolt, the firm started out making metal prefabs after the Second World War and then diversified into a variety of prefabricated, demountable, recyclable and permanent building systems, all based on an absolute minimum of site work and a maximum of factory production - using structural rectangular hollow and cold-rolled galvanised sections, and galvanised steel strip. Today, while the firm's design-and-build division in Nottingham concentrates on health and education work and bespoke office buildings, the production facility in Milton Keynes, working closely with British Steel, is concentrating on refining the production process for three basic product lines - the Prospex volumetric system; a flatpack system called Unitrex; and the Matrex steel framing system. Of the three, Prospex and Matrex are presently in the ascendant, with one of the production lines turning out the pre-wired, plumbed and decorated Prospex motel bedroom units for Granada Travelodge, but there are other projects in the pipeline. These range from a new dry-assembly rainscreen brick slip cladding - to satisfy local planners who insist on brick finishes despite the huge delays imposed by wet trades - to projects for 20-storey prefabricated Millennium hotels in Docklands, using five-storey clusters of Prospex units supported by a heavy-gauge Matrex frame, and longer-range plans to re-enter the housing market with factory-made full-size prefabricated service cores incorporating plumbing, electrics, appliances, electronics and it for volume housebuilders to erect their own houses around.
One of the most common criticisms of modular and volumetric structures is that they are dull. Whitehouse is convinced that this is not a failing of the factory-made approach, but often a consequence of client preferences and planning requirements. 'The irony today is that architects often make traditionally built buildings look as though they were machine-made, whereas we have to make what really is a machine product look as though it is traditional. It needs architects to get hold of the concept of modular pre-engineered buildings and work with Terrapin and similar companies to get the product to look as good as it is technically. Once the substructure is complete, we can deliver a 40-bed hotel and complete erection in two to three days. Snagging that used to take two days; now it takes two hours. This sort of building speed and low incidence of defects makes good business sense. With a hotel chain, a contract can be as short as 12 weeks from planning permission to the handover of the keys. It's not the building that takes the time, it's the bureaucracy.'
Previously Terrapin did not have the volume it needed to achieve economies of scale and continuity of work. Now it has, all kinds of benefits have resulted. Continuous production has meant that changes and improvements can be incorporated in the factory immediately. 'It makes you realise how tenuous communications are between the design team and the site in conventional construction,' says Whitehouse. 'Factory production of buildings has a natural feedback loop that site construction can never match.'
Nor is technology transfer forgotten. The hydraulic rivetting guns Terrapin uses are silent and do not penetrate the steel sections, thus retaining the integrity of their galvanised coatings - 'the same system is used in Audi cars', says Whitehouse with pride. He also mentions his other pet piece of automobilia, the modified Classic Car rotating chassis jigs that turn 18m2 Prospex modular roofs upside-down so that the ceilings can be fitted from above instead of below.
Terrapin has its own Japanese operation, with the Matrex framing system acceptable to local building regulations and earthquake codes, but Whitehouse insistent that there is nothing magical about the Japanese factory-made house. 'It is the process they have mastered, not so much the product. What we have learned from them is the importance of total control of the process.'