Basement Waterproofing & Damp Proofing in London

Cost depends on the size of the basement, the water conditions, the system specified and how accessible the property is. A simple cavity-drain membrane installation sits at the lower end of the range, while a full basement conversion with tanking, drainage and finishing runs considerably higher. We give you a fixed written quotation after a free survey — no obligation.

Tanking (Type A) is a barrier system — a cementitious coating that physically blocks water from entering. A cavity drainage membrane (Type C) is a managed system — a studded membrane behind which any water is directed to a sump and pumped away. For habitable London basements we usually recommend a Type C system, or a combination, because it manages water rather than relying on a single barrier.

These are the three approaches defined in BS 8102, the British Standard for waterproofing below-ground structures. Type A is barrier protection (tanking), Type B is structurally integral protection (waterproof concrete), and Type C is drained protection (cavity drainage membranes with a sump and pump). We assess each property and often combine types for reliable, code-compliant protection.

Rising damp typically shows as a tide-mark up to about a metre from floor level, often with salt staining. Penetrating damp appears as localised patches linked to a defect — a leaking gutter, cracked render or bridged cavity — and can occur at any height. Condensation shows as surface mould in cold corners. A professional damp survey identifies the true cause before any treatment is specified.

Yes. We install manufacturer-approved systems and provide written guarantees on our workmanship and the materials used. The exact term depends on the system specified, and we explain it clearly in your quotation.

Yes. A qualified surveyor visits the property, diagnoses the problem and provides a written report and fixed-price quotation at no cost and with no obligation — across London and Greater London.