Copyright: David Lawson 1999Home page
New methods of procurement and fabrication have slashed construction costs on schemes ranging from major greenfield office blocks to inner-city housing, a packed debate at the British Council for Offices annual conference in Glasgow heard last week. Building costs have been cut from 90 pounds to 80 pounds a sq ft on office developments for KLM at Heathrow and Stansted and developer BAA Lynton is now aiming for another 10% reduction. Aptly, a† partnership approach is a major reason behind the cuts. Chief executive Sir John Egan is putting into practice the major finding of his report into† revolutionising the construction industry.
'We found that 40% of on-site spending was on things that do not add value such as mismatch of components and poor site supervision,' Alistair Taylor of BAA Lynton told the workshop. Just ensuring the steelwork was the right size has made a major contribution.The design process has also changed with sub-contractors brought around the table from the start, added Bob Dalzeil of architects Geoffrey Reid. Full 3d CAD modelling is used to 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. This could be extended to series of buildings in business parks. BAA Lynton wants to eventually offer a menu for clients to pick premises off the shelf for construction in 25 weeks.†Architects should not fear this kind of standardisation as a compromise on design, said† Dalziel. It had 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. He pointed to a housing development for Peabody Trust in east London where the construction program had been halved to six months by constructing modules off-site.†'That was worth 100,000 pounds 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. A nearby site had seen a huge amount of conventional brickwork condemned as below standard. Prefabricated 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.† Material and waste storage problems on† tight inner-city sites are also overcome. It was apt that this was the¬† most impressive advantage seen by the main contractor, Kajima. Some 25% of housing in Japan is prefabricated, said Pickard. in sheer numbers this is more than the total UK new-build market.