How do I Waterproof a Basement?

Homeowners who waterproof a basement can typically expect to increase the value of their home and reduce costly repairs in the future. Epoxy and latex waterproof mixes are commonly-used sealants that are effective at sealing the walls and floor of a basement. Sealants can help reduce structural rot and insect infestation, both of which are common in basements that have water leaks. Water usually flows through a path of cracks and holes in the wall to enter the basement, but water can also seep directly through the wall as a result of outside water pressure. To waterproof a basement, existing wall damage should be repaired and a waterproof barrier should be put in place.

The first step to waterproof a basement is to determine how water could enter the basement by conducting a visual examination. Typically, walls that have cracks and holes are more susceptible to water leaks. Hairline cracks can be filled with a waterproof mix while larger holes often require a cement patch that consists of one part cement and two parts of fine sand. Generally, a small amount of water is added to the cement mix, giving it a very thick consistency. Before applying the cement, the hole or crack should be clean and free of loose rocks.

Once all the cracks and holes have been patched, a fine mist of water is usually sprayed on the surface of the wall to prepare it for the waterproof mix. The waterproof mix, which consists of cement and a water-resistant polymer, is diluted with a specific amount of water, as directed by the manufacturer on the packaging label. To waterproof a basement successfully, the waterproof mix needs to be prepared accurately.

After the wall dries, the waterproof mix is applied to the lower part of the wall with a stiff brush. Progressing toward the top with a circular brushing motion is generally the best way to fill the individual pores of the wall. After the wall is covered with one layer of waterproof mix, a second layer is applied, starting from the top and finishing at the bottom. Once the waterproof mix has dried, the wall is typically sprayed with water and allowed to settle overnight. The final step to waterproof a basement is to wet the surface of the wall the following day and apply a final coat of waterproof mix.

It also may be a good idea to address some of the issues that may cause water to enter the basement. For example, clogged gutters and downspouts that collect water should be cleared, and the location of the downspout should be adjusted so the water is directed away from the basement. Installing a dehumidifier in the basement can also help reduce moisture in the air.