Which chemical is used to stop water leakage?

Which chemical is used to stop water leakage depends on type of leak, material, and location, as different chemicals are used for waterproofing and sealing. Common chemicals include polyurethane injection foam, which is two-component chemical that expands when injected into cracks in concrete foundation, sealing leaks from inside, widely used for basement leaks. Epoxy injection is another chemical used for structural cracks, bonding concrete and stopping water with strong adhesive. For surface waterproofing, cementitious waterproofing chemicals like crystalline waterproofing containing Portland cement, silica, and active chemicals that grow crystals in concrete to block water, brand names like Xypex and Krystol. Liquid rubber membrane and bituminous coatings are used for exterior foundation. Silicone sealants and polyurethane sealants are used for joints around windows and pipes. Sodium silicate, or water glass, is used to seal concrete. For emergency pipe leaks, epoxy putty sticks containing epoxy resin and hardener can stop leak temporarily. For roof leaks, acrylic polymer sealants and silicone roof coatings are used. For general leak repair, hydraulic cement containing calcium aluminate expands and stops active water flow quickly. In water treatment, polyurethane grout is most common for stopping active leaks in concrete, as it reacts with water to form foam. Choice depends on whether leak is active or preventive, concrete or pipe.