TOWERING TIMBER: Claimed to be the tallest timber frame building of its type in the world, the six storey TF2000 structure at the Building Research Establishment's Cardington centre was opened by construction minister Nick Raynsford last week. The building, which was erected in just three weeks, represents a typical residential block with four two- bedroom flats on each floor around a service core. Brick cladding will be added before an extensive programme of testing begins. It is funded jointly by the government and industry under the Partners in Technology programme. Other project collaborators include BRE and TRADA Technology.