Basement Waterproofing Calculator
Calculate waterproofing material quantities for Type A (tanking slurry), Type B (structural concrete), or Type C (cavity membrane with sump pump) systems per BS 8102.
Total internal basement wall area
Internal basement floor area
How We Calculate This
This calculator determines material quantities for the three main basement waterproofing systems defined in BS 8102:2022 (Code of Practice for Protection of Below Ground Structures Against Water).
Type A — Tanking
Cementitious slurry is applied in multiple coats to wall and floor surfaces. Quantity = total area × coverage rate (kg/m²) × number of coats. A typical 3-coat application uses 4.5 kg/m² total.
Type B — Structural
Reinforced concrete designed to be waterproof in itself (watertight construction per BS EN 1992-3). Wall thickness typically 250-300mm, slab 200-300mm.
Type C — Drained
Cavity drain membrane (studded HDPE sheet) is fixed to walls and floor with a channel drain at the perimeter collecting water to a sump pump. Membrane area includes a 10% overlap allowance.
Frequently Asked Questions
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Last updated: March 2026
All calculations are estimates. Verify with your supplier.