WaterBlock Acrylic Masonry Waterproofer is designed to waterproof interior or exterior masonry surfaces such as basement walls, foundations, retaining walls, exterior masonry walls, etc. It is alkali resistant and provides positive sealing and waterproofing over bare concrete block, brick, stucco or tilt up concrete walls. No pre-mixing or surface pre-wetting is necessary with this product. This product contains an agent that inhibits the growth of mildew on the surface of the paint film.