Furnival House

Temporary Works: Foundation advice and Temporary Works Design
Client: City Basements
Project value: £5m

Furnival House is a large detached Grade II listed Building built by Joseph Pitt between 1916-1919 for the domestic staff of the Prudential Assurance Company. It is described as ‘a handsome Edwardian Baroque institutional building’ receiving listed status by English heritage in 2008.

Structurally, it is formed in heavy load bearing masonry with concrete filler-joist floors. Apart from the ground floor, all these were to be retained in the new development. It occupies a steeply sloping site and is founded on sand overlying wet Claygate Beds with London Clay at depth.

Works comprised the creation of a deep basement underneath the existing building with depths varying between 4-7m due the sloping nature of the site.

CDS were appointed as Structural Engineering Consultants to Groundworks specialist City Basements Ltd. to advise on foundation and Temporary Works design. The project value of substructure works alone was £3.5m.

CDS designed the perimeter sheet piling and associated temporary propping; temporary bearing piles with needling to support existing superstructure during basement construction; underpinning; piled tower crane base and miscellaneous internal temporary works.

CDS also undertook foundation value engineering fundamentally obtaining acceptance to adopt a raft solution over piles. Due to the high loads, ground conditions and restricted access beneath the existing building, piling was not a viable option. This was verified independently by geotechnical consultants GCG (Geotechnical Consulting Group) and subsequently accepted by the Design Team.