Bridport House is part of the comprehensive redevelopment of the London Borough of Hackney’s Colville Estate. 100% social housing, Bridport House replaced an original 1950s block housing 21 flats with two new joined blocks, one eight storeys high and the other five storeys, to provide 41 new homes.
It forms part of a wider regeneration programme within Hackney to replace 438 existing homes with approximately 900 homes of between one and four bedrooms, more than half of which are allocated for social renting and shared ownership.
Innovative design and rapid construction
Bridport House is a highly innovative cross laminated timber (CLT) multi-storey residential building. Designed by architects Karakusevic Carson, it was completed in 2011 and was the first time a multi-storey building had been constructed entirely from CLT including the ground floor.
The London Borough of Hackney received £3.4 million local authority new build match-funding from the Homes and Communities Agency (HCA). To qualify for this funding, the architect had just 18 months from appointment to building completion to meet the deadline. “The CLT framework was put up in just ten weeks. With traditional construction, it would have taken 20-24 weeks,” said Paul Karakusevic, Karakusevic Carson Architects.
Engineered strength and light weight
In addition, one of London’s main drainage tunnels runs directly underneath the building. This meant that little extra weight could be exerted while the capacity of the block had to be doubled from 21 to 41 new homes. The building was therefore unsuitable for a heavy traditional concrete frame structure.
The unique properties of CLT’s engineered strength combined with its light weight made it the ideal solution to overcome this problem. The structure was designed so that the load-bearing CLT panels are placed in a variety of positions on each floor, thus spreading the load. The floors, walls, and ceilings are all made from CLT. As CLT spreads its weight along a line, rather than a point, it was possible to double the height of the original structure, while only increasing its loading by 10%.
Fiona Duncan, head of area for North East London at the Homes and Communities Agency, explained, “We provided funding of £3.4 million for this innovative project to help Hackney Council increase the provision of affordable homes for local people and can see how this method of construction has the potential to be replicated on other suitable schemes.”
The raw material used in the manufacture of the CLT boards is PEFC-certified spruce. It was sourced and supplied by Austrian Stora Enso Wood Products and engineered by Hackney-based specialist timber contractor Eurban. The solid timber construction makes the project carbon neutral for the next 30 years, while its prefabricated nature ensures the units are fully airtight, helping the project achieve Code for Sustainable Homes Level 4. “The air testers said it was the most airtight construction they had ever measured” explained Paul Karakusevic, Karakusevic Carson Architects.
In addition, the building has a brown roof and 60 solar panels, which generate enough electricity to power the external lights and the lighting of common areas in the building. Consequently, since moving into the building, residents have halved their gas and electricity bills.
Next phases underway
Work is now underway for the next phases of Colville’s regeneration, following the demolition that began last year. Higgins Construction was appointed to build Phases 2A and 2B, which include 70 new Council homes for social renting and six for shared ownership, in addition to 40 for private sale.
Anthology was appointed in July last year as development partner for the third phase, to build 198 homes for private sale, which will help pay for the new Council homes for social renting and shared ownership across the rest of the Colville estate.