With the pressure on land for development in city centres, and the capital’s ongoing housing crisis, there is an increasing realisation that the roof spaces above existing residential and commercial buildings possess the potential to accommodate much needed new housing. It has been estimated that 40,000 new homes could be accommodated on existing roof spaces in Central London alone.
This project involves the construction on an additional storey on top of an existing block of flats in the heart of London. The existing residential block dates from the late 1950s and occupies a tapering site where two streets of Victorian white stucco terraces converge.
The new construction is designed to read as an addition, set back from the perimeter of the existing building below, reducing the visual impact of the new structure when viewed from the street. The elevations are simple compositions of crisp zinc cladding panels set next to generous areas of full height glazing. Internally the plan is arranged around a large, open plan living space with the walls mirroring the profile of each adjacent site boundary. The glazed panels frame views out across the surrounding roofscapes on all sides, exploiting the elevated position of the site and amplifying the sense of connection between internal and external spaces. A new lift serving the additional storey is provided within an existing external lightwell.
Airspace development of this nature presents a particular set of challenges that need to be addressed as part of the design process. Chief amongst these is establishing that the existing structure has the capacity to accommodate the additional load of the proposed new construction. This was achieved through detailed surveys of the existing structure.
The primary structure of the addition is formed from a series of steel frames, which are fixed via structural acoustic collars that reduce levels of acoustic transmission to the existing structure below.
Clear strategies also need to be developed with regards to services, acoustics and fire. Careful attention was paid to developing the design to take account of the fact that the building will be occupied during the works. This required close collaboration between all consultants within the design team and with the client, who was closely involved with the design process. Syte Architects managed this process as lead consultant and Principal Designer on the project.
Construction is due to start on the project in 2019.