Kryton Buildmat Co. Pvt. Ltd. Manufactures Waterproof Grout to Repair Leaking Cracks. Kryton Buildmat Co. Pvt. Ltd. Is an ISO 9000 certified company that manufactures Crystalline Concrete Waterproofing Systems. The Waterproof Grout to Repair Leaking Cracks is specially designed to repair leaking cracks, holes and joints in concrete. It contains special ingredients that react chemically with concrete to form millions of needle shaped hydration crystals. These crystals grow deep into the capillary pores of the grout and surrounding concrete to block the passage of water.