Concrete absorbs water. This is evident just by looking at streets or driveways after a rain. The surface is wet. It eventually dries as it is either absorbed all the way or it evaporates into the air. So how do you keep a basement dry? Why doesnâ€™t the water from the ground absorb into the basement walls? Well, actually sometimes it does. When that happens, you see a wet basement floor or wet walls. This can also cause the concrete to crack.
To prevent this from happening to the library, waterproofing is put on the outside of the walls before the ground is put back into place. This waterproofing is a gooey substance that is troweled onto the concrete and then allowed to dry. This bonds to the concrete and becomes a seal which then prevents water from penetrating the concrete. Depending upon the humidity and the temperatures, the waterproofing can dry in less than a day.