Waterproofing Membranes: Waterproofing membranes, both liquid and sheet types, are commonly used in bathrooms. Liquid membranes are applied as coatings on surfaces like floors and walls, creating a seamless barrier. Sheet membranes, such as PVC or rubber, are applied to surfaces before tiling. They provide a reliable waterproofing layer. Shower Pan Liners: For shower floors, a shower pan liner is often used. It's a waterproof membrane installed under the mortar and tile to direct water toward the drain. It prevents water from seeping into the subfloor.