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CLW
33-35 Piccadilly, DSDHA scheme with a two-storey basement extending over the entire site

Project case study

33-35 Piccadilly

Waterproofing design consultant for a two-storey basement extending over the entire site at 33-35 Piccadilly, with DSDHA as architect and Heyne Tillett Steel as structural engineer.

33-35 Piccadilly is a central London scheme with DSDHA as architect, Heyne Tillett Steel as structural engineer and Kier as client. CLW was commissioned as the waterproofing design consultant for a two-storey basement which extends over the entire site, together with the podium areas above it.

A full-site basement leaves no margin at the boundaries, every junction with neighbouring structures and the podium above is a waterproofing interface that has to be resolved in the design, not on site. CLW worked closely with the entire design team to provide a clear and efficient design for the Grade 1b and Grade 3 spaces.

The waterproofing design is tailored to suit the final basement construction, with either Type A (cementitious slurry) or Type B (structurally integral) protection, combined with Type C (drained cavity). Holding both primary options open against the structural solution, rather than fixing a product early, is what keeps the design honest to how the basement will actually be built.

Image credit: DSDHA.

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Independent waterproofing design from RIBA Stage 2 through construction monitoring. Defensible, document-led, contractor-agnostic.