Vapour barriers or moisture barriers are films made from synthetic materials (usually polyethylene, also called PE films) that should limit the penetration of moisture from the subsurface into the laminate floor. They need only be installed on mineral subfloors such as stone, concrete, asphalt, because under certain climatic conditions water vapour can precipitate as condensation and cause structural damage. The vapour barrier is laid trough-like or “floating”. The rows are laid next to each other with approx. 20cm overlap and affixed with masking tape (see installation guide).