How do I protect the substrate under water-permeable tiles from liquids?

A suitable separation layer between the substrate and the water-permeable tiles prevents water and spilt liquids from reaching the existing floor.

The required specification of the separation layer depends on the installation location, intended use, substrate and anticipated moisture exposure. On parquet floors in historic buildings and on timber sports-hall floors, a liquid-tight but vapour-permeable separation layer is recommended. In these applications, the rubber covering primarily protects the timber floor against mechanical damage, while the separation layer keeps water and spilt drinks away from the substrate and allows any residual moisture already present to escape as water vapour.

Moisture-insensitive substrates such as natural stone, tiles, glass and metal generally require no additional protection. If a separation layer is nevertheless required, a fully adhered protective film may be used. Its seams and perimeter junctions must be liquid-tight.