Wall Waterproofing - Positive & Negative Pressure

Hydrostatic pressure waterproofing performance is tested by applying water pressure to one face of a cured membrane or treated concrete substrate and measuring the depth of water penetration (EN 12390-8) and/or the pressure at which water breakthrough occurs (DIN 1048). Products are typically rated in bar or metres water column (1 bar ≈ 10 m water head). For a basement at 3 m depth with a water table at ground level, the hydrostatic pressure is approximately 0.3 bar or 3 m water column at the base of the wall. Gemite specifies products and application thicknesses appropriate for the maximum water pressure calculated for your structure.

Wall surfaces must be structurally sound, clean, and free from dust, grease, paint, curing compounds, efflorescence, and loose material. Active cracks and leaking joints must be sealed with plugging mortar before membrane application. Honeycombs and voids must be filled with repair mortar. For positive-side application, the substrate must be saturated surface dry (SSD) - neither bone dry nor running wet. Our technical data sheets specify the minimum compressive strength of the substrate (typically ≥ 25 MPa for concrete) and the surface preparation method.

Gemite's crystalline and cementitious waterproofing systems are specifically formulated for application on damp or wet concrete substrates. The presence of moisture is actually beneficial for crystalline systems - it triggers the chemical reaction that forms the crystalline barrier within the concrete. However, application during rain, frost, or when the ambient temperature is below +5°C is not permitted. Our technical team will specify the temperature and humidity limits for your project's application conditions.