Project case study
7 Ridgemount Street
RIBA Stage 3 review of the structural waterproofing design for the refurbishment, partial demolition and extension of a 1960s office building in the Bloomsbury Conservation Area.
7 Ridgemount Street comprises the refurbishment, partial demolition and extension of an existing 1960s commercial office building within the Bloomsbury Conservation Area, with DSDHA as architect, HTS as structural engineer and Opera PM as project manager for Sebre. CLW was commissioned to review the structural waterproofing design at RIBA Stage 3.
The basement extends beyond the building line at ground level, so the scheme includes buried deck and podium elements, the parts of a below-ground envelope that fail most often because they sit at the junction between structure, landscape and drainage. The design specifies Type B (structurally integral), Type C (cavity drainage) and Type A protection to achieve Grade 3 and Grade 1b performance in accordance with BS 8102:2022.
Working closely with the architects, structural engineers and main contractors, CLW developed a robust waterproofing design strategy, with the Stage 3 review used to fix the grades and system combinations before procurement rather than leave them to be resolved by the supply chain.
Working on a comparable scheme?
Independent waterproofing design from RIBA Stage 2 through construction monitoring. Defensible, document-led, contractor-agnostic.