Most basement failures we get called to are not coating failures. They are specification failures — a product picked for a damp wall, then asked to hold back standing water.
Start with the water, not the product
Before anyone quotes you a membrane, establish two things: where the water table sits in August, and whether the water is static or moving. A slurry that performs perfectly on a damp retaining wall will blister under three metres of hydrostatic head. That is not a defect in the product; it was never asked the right question.
Match the system to the exposure
Damp, no head of water
Cementitious slurries and crystalline systems are efficient here, and they tolerate a green substrate better than most acrylics. Two coats, cross-directional, with mesh at corners and construction joints.
Positive-side, with head
Move to a membrane. Self-adhesive bituminous sheets or torch-applied rolls, with a protection board before backfill. The detailing at pile heads and pipe penetrations is where these systems live or die — not on the flat.
Negative-side, already leaking
Injection grouting first to stop the active flow, then a crystalline coating so the concrete itself keeps sealing. Coating over a live leak is money on the floor.
If a supplier quotes you a system without asking about the water table, you are buying a product, not a solution.
Three checks before the crew starts
- Substrate moisture and surface strength — measured, not judged by hand.
- Joint and penetration details drawn, with the mesh and sealant specified.
- A written dosage and coverage rate per coat, so the second coat is not half a coat.
If you want the specification for your own drawings, send them over. We return the detail and the coverage rates, and you can put your consultant's name on it.
