Floor Waterproofing Under Tile & Stone Finishes

Gemite's floor waterproofing membranes are applied in a minimum of 2 coats - the first coat is applied perpendicular to the second to ensure complete, pinhole-free coverage. The minimum total dry film thickness (DFT) is 1.0-1.5 mm depending on the product and exposure class. At floor/wall junctions, fabric reinforcement tape is embedded in the first coat before the second coat - providing crack resistance at the most vulnerable joint. Our technical data sheets specify exact coverage rates, number of coats, and drying times.

Not under all tiles - only in areas classified as wet zones (W1, W2, W3 per DIN 18534 or equivalent national standard). W3 (continuously wet, such as shower trays and pool surrounds) requires a more robust system than W1 (low moisture, such as toilets and kitchens). Gemite specifies the appropriate membrane thickness and system for each wet zone classification. In the UK, compliance with BS 8000-11 and the tile industry's TCAS guidance applies.

Cementitious waterproofing membranes require a rigid, dimensionally stable substrate. Timber subfloors are subject to moisture-related movement and deflection under loading - both of which will cause cementitious membranes to crack. For timber subfloor applications, a decoupling membrane is required between the timber and the cementitious system, or a flexible system specifically tested for timber substrates must be specified. Contact our technical team for guidance on timber substrate applications.