Project case study
1 Hanover Square
Waterproofing design consultant for the redevelopment at 1 Hanover Square, partial demolition, refurbishment and extension with a new sub-basement under a retained building.
1 Hanover Square is a Mayfair redevelopment led by Piercy & Co for Nautilina Limited, comprising partial demolition, refurbishment and extension of the existing building, with a new sub-basement at B2 beneath a refurbished existing basement at B1. CLW was commissioned as the waterproofing design consultant, working under Avison Young as project manager with Heyne Tillett Steel as structural engineer.
The scheme combines retained and new below-ground structure, plus buried deck and podium elements, which is the combination that puts most pressure on a waterproofing strategy. The design specifies Type A, Type B and Type C protections to achieve Grade 3 and Grade 1b performance, with the grade and system selection mapped to what each part of the structure, retained or new, can actually deliver.
The design was developed in close coordination with the architects, structural engineers and main contractors, and in line with Westminster’s retrofit strategy, producing a robust waterproofing design that treats the retained basement and the new sub-basement as one continuous below-ground envelope rather than two separate problems.
Image credit: Piercy & Co.
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Independent waterproofing design from RIBA Stage 2 through construction monitoring. Defensible, document-led, contractor-agnostic.