udes 7 one-bedroom apartments (59 square metres), 14 two-bedroom apartments (80 square metres) and two penthouse apartments with two bedrooms (102 square metres).|
4.1. CLT Building 1: ‘Stadthaus’ Multi-Apartment Building in Murray Grove, Hackney, London
The ‘Stadthaus’ was designed by Waugh and Thistleton Architects, and built in 2008. The 9-storey building is a project of local developer Telford Homes and the Metropolitan Housing Association. There are 19 private apartments, 10 social housing units and a residential housing office located in the building. The apartments are a mix of one, two and three bedroom accommodation . The brief of the client was that it needed to look and feel the same as if built in concrete, to avoid issues of acceptance. After the ground floor was constructed the remaining construction was undertaken without a fixed crane in place, and each storey was assembled in three days using four carpenters. The entire building process took 49 weeks with the construction of the 8 CLT storeys taking only 12 weeks. The CLT for walls and floors was sourced from Austria and constructed using the system of KLH in Austria: like a kit of parts, the CLT panels are up to 12 metres long (limited by size for transport; 12 metres is the largest size that could be transported through the channel tunnel to the UK) and weighed a maximum of 15 tonnes. The weight limit allowed use of a mobile crane. The foundations are cast in situ concrete piles designed to accept the weight of a concrete framed building of similar size—a decision to ensure procurement alternatives . Wells notes that the lift core and stairwells are all made in timber. The architect stated that meeting building code requirements for fire was relatively straightforward, relying on the self-protecting properties of timber which can retain its strength during fire for longer periods than steel [54,55]. At the beginning, the unusual construction system was kept secret from the apartment buyers by the developer and all internal wall surfaces were covered with gypsum panels, to avoid confusing potential buyers. However, the innovative timber structure was leaked to the press and stories were published in the newspaper. Apparently, all 29 apartments were sold within two hours to buyers, many enthusiastic about the more environmentally friendly construction method.
4.2. CLT Building 2: Bridport House, Hackney, London
The eight-storey Bridport House is (at the time of writing), with Stadthaus, the tallest all cross-laminated timber (CLT) building in the UK (both were constructed for the same developer client and the London Borough of Hackney). Both have pushed the boundaries of CLT construction up to eight storeys, although Stadthaus is marginally taller at nine storeys, featuring a concrete ground floor, whereas Bridport House is CLT from the ground up. Bridport House replaces an original 1950s block with 41 new homes in two joined blocks, one eight storeys and the other five storeys high. All elements from the ground floor upwards are of cross-laminated timber, manufactured and supplied from Austria by Stora Enso Wood Products–including the lift shaft. Below ground level the raft, foundations and lift pit are of reinforced concrete. Often in such projects the ground floor will be concrete because it is used for retail and needs larger facade openings. At Bridport House, however, the lowest two floors are occupied by residential maisonettes that have been oriented in a different direction from the apartments above. In the design phase, reinforced concrete and structural steel was compared in detail with the use of a CLT system (Eurban ran a detailed comparative analysis). There are several reasons why CLT was selected: one was weight. CLT is considerably lighter than the alternative structural materials, as a large Victorian sewer runs beneath the site and point loads needed to be avoided. Speed of construction was another benefit of CLT which can take as little as half the time to construct as a conventional reinforced concrete frame. In addition, the constru