UGL Drylok Gray Masonry Waterproofer. 5 Gallon. Formulated to waterproof above or below grade masonry walls, cinder and concrete blocks, stucco, brick, retaining walls, basement and foundations. Helps protect against radon gas penetration by reducing vapor transfer, tintable and low odor. Easy cleanup with warm, soapy water, no pre-mixing or pre-wetting, plus more.