Many people think of concrete as a highly durable material. While this is true, concrete is also a porous compound that is highly susceptible to staining and water damage which can eventually lead to structural and aesthetic problems. To prevent this, a concrete sealer is applied over the surface of the concrete. When applied correctly, this sealer creates an impenetrable barrier that shields concrete from surface damage, corrosion, freeze-thaw damage, and staining. Concrete sealers either block the pores in the concrete to reduce absorption of water and salts or form an impermeable layer which prevents such materials from passing.