Many homeowners underestimate how much damage water can cause when it comes into contact with a foundation wall. Over time, rain, melting snow, and groundwater put constant pressure on the walls of a foundation. This pressure, known as hydrostatic pressure, pushes water into even the smallest gaps. Without foundation wall waterproofing, these walls begin to deteriorate, allowing water to enter basements and crawl spaces. The result is damp air, mold, mildew, and expensive repairs.