Abstract: A waterproof sheet used to waterproof structures has a single layer of non-degradable, water impermeable polymeric membrane that has layers of particles of non-hydrated sodium montmorillonite (sodium bentonite) adhering to the membrane in a uniform layered thickness. The layers of particles of sodium montmorillonite spaced from the membrane adhere to each other, with a coating material (adhesive) that is designed to provide the necessary performance for waterproofing. A water soluble dye is provided in the layer of particles so if a tear occurs in the impermeable membrane and water contacts the particles, the dye will stain the membrane and mark the location of the tear.