3-ply waterproof membrane protects floors and walls under thin-set tile installations from substrate cracks and moisture migration. Sealing and decoupling membrane to be applied with tiles or natural stones for safe decoupling and perfect waterproofing. If used as indoor waterproofing membrane suitable for medium to high loads of non-pressurized water but only to be applied on floors (e.g. floors of domestic bathrooms and sales floors with large-size tiles or on outside balconies and terraces where no living space is situated underneath).