Concrete Waterproofing
Concrete looks like a very solid material, but it is porous and is easily damaged if not properly prepared and cared for. Its porosity allows water penetration which in turn weakens the concrete, whether it is a driveway, foundation, retaining wall or block fence. Pieces of the weakened material will break away, particularly on horizontal surfaces that are stressed by foot and vehicular traffic. This is even more of a problem in areas with a freeze-thaw-cycle where the ice expands and damages the concrete even more than the water alone.
Concrete surfaces must be sealed against the infiltration of water and other liquids. Sealers come in a variety of forms, the more common ones being light viscosity chemicals that penetrate the pores, they then cure, forming a vapor barrier. Most of these products are colorless and leave no residue after curing. Consumer size packaging of water-seal products are readily available at the local home center or paint store. Commercial size packaging is available from industrial suppliers.
Elastomeric coatings for concrete waterproofing are a more decorative alternative than clear sealers. As their name implies, elastomeric coatings move with the expansion and contraction of the concrete substrate, providing an elastic membrane that repels water and other liquids. Most of these coatings may be tinted to a wide variety of colors and come in assorted textures, from smooth to a coarse aggregate. Most of the elastomerics are intended for vertical substrates, but a few may be applied to traffic surfaces.
Below-grade concrete foundations require a much heavier waterproofing coating, since they are also subjected to the pressure of damp, water-laden earth. Many of the products used in this application are tar based.
