C2 Guard for MasonryC2 Guard for Masonry is a non toxic product designed for unsealed concrete and masonry surfaces. C2 Guard is absorbed deep into the surface, forming a polymer barrier and becoming part of the masonrys structure. This enhanced structure resists water penetration and helps prevent corrosion, cracks, and mold mildew. Best of all it helps protect concrete and masonry from de icing salts and pool chemicals. This is our top pick for preserving concrete and