Great James Street, London – Projects

Our client, a private property owner, wanted to create a showpiece office space to attract new opportunities to their business. The proposal was to replace the original mishmash of single storey extensions to the rear of their 5 storey Grade II Listed Georgian Terrace property into a high-quality, open-plan working space with sculptural roof form. The work also included excavating the lower ground floor to create additional headroom whilst retaining a listed masonry vault. The landlocked site is surrounded by similar buildings, with land access only possible through buildings. Delivery of large elements would require use of large cranes and therefore road closures, so this heavily influenced the choice of structural solution.

The form of the roof required us to produce physical models to understand its structural behaviour. From these preliminary models it became clear that the panels, which formed both ridges and valleys, would be structurally stable provided the perimeter nodes were horizontally restrained. This in turn would mean the nodes could not move vertically. The result was a system of panels that transferred load in bending, but were effectively propped off each other. The structural solution was a timber stress skin roof panels, all fabricated on site, with no structural steelwork thus avoiding any requirement for craneage.

In the new basement, an original brick vault is reinvented as a meeting space, and became a new support to the ground floor structures, which in turn were used to prevent thrust of the vault. 

The ground works also involved dealing with a number of unexpected issues including voids under party walls, hidden vaults and very poor ground conditions