How is a flat roof waterproofed with liquid-applied waterproofing?

Flat roof waterproofing can be carried out using ALLESDICHT liquid-applied waterproofing applied in at least three coats. A seamless, permanently elastic surface that resists ponded water is essential, as rainwater does not drain as freely from a flat roof as it does from a pitched roof. It collects in depressions and around junctions, where leaks develop first.

The substrate must be clean, dry and sound; suitable substrates include concrete, bitumen, sheet metal and plastic. The liquid-applied waterproofing can be brushed or rolled on, and on large surfaces it can also be applied by airless spraying. Once dry, it forms a seamless rubber membrane that bridges cracks, accommodates movement in the substrate and remains watertight under ponded water.

Roof outlets, rooflights, roof edge terminations, and pipe and cable penetrations are subject to particularly high stresses and require special attention. At these points, the waterproofing is reinforced with an embedded fabric layer. Where an existing flat roof has isolated damaged areas, localised reworking with ALLESDICHT is often sufficient, without a complete replacement of the roof waterproofing system.