Penetrating Brick & Masonry Seal. Commonly used for sealing and strengthening brick and mortar but can be used on a wide variety of cementicious materials. Penetrates up to 4″. Leaves no slippery film on the surface. Vapor-permeable. Use on chimneys, brick walls, fireplaces, pavers, concrete, retaining walls, splitface blocks, and even wood! Water-based SAFE!