New methods of procurement and fabrication have slashed construction costs on schemes from greenfield office blocks to inner-city housing, a packed debate at the bco conference heard last week.
Building costs have been cut from £90 to £80 pounds per sq ft on office developments for klm at Heathrow and Stansted, and developer baa Lynton is aiming for another 10 per cent reduction. Using a partnership approach is a major reason behind the cuts: baa chief executive Sir John Egan is putting into practice the major findings of his report into revolutionising the construction industry.
'We found that 40 per cent of on-site spending was on mismatch of components and poor site supervision,' Alistair Taylor of baa Lynton told the workshop. The design process has also changed, with sub-contractors brought in from the start, added Bob Dalzeil of architect Geoffrey Reid, and cad modelling can show how the finished product may, or may not, work.
The aim is to develop standardised 'clusters' of components that can be slotted in to speed development, or even form series of buildings in business parks. baa Lynton wants to offer eventually a menu for clients to pick premises 'off the shelf' for construction in 25 weeks. Architects should not fear such standardisation as a compromise on design, said Dalziel. It has a long and honourable history, including Classical and Georgian building.
Prefabrication will play a big role in cutting future costs, according to James Pickard of Cartwright Pickard, pointing to the housing development for Peabody Trust in East London (aj 1.4.99) where the construction programme was halved to six months by constructing modules off-site. 'That was worth £100,000 in rent to the landlords,' he said. 'It won't be long before this is realised by commercial developers as well.'
Prefabrication would help overcome skill shortages, which lead to so much waste, as components are tested for flaws by the manufacturer rather than being rejected on site. Full mock-ups can also be shown to clients in the factory and tweaked to their needs. Prefabrication also overcomes material and waste storage problems on tight inner-city sites.