One aspect of basement construction that is often overlooked is the waterproofing stage. Because basements are partially or completely underground, water will always find its way through the basement walls (concrete or block). There are several procedures available to the homeowner--sealing walls and floors or diverting water--that can and will waterproof a basement and prevent water buildup. It isn't difficult, and, depending on the size, it can be done in as little as a day.
Pre-Construction Floor Preparation
One area that is often overlooked is the basement floor. Usually concrete, it should never be poured directly on top of dirt or gravel. Thick mil plastic should be spread as a last layer before concrete is poured. This plastic will prevent any water from transferring from the dirt underneath and up through the floor.
One important aspect of waterproofing a basement is to make sure that any excess water is channeled away from the home's foundation. By laying 8- or 10-inch perforated pipe along the footers of the basement wall and covering it with gravel, you will ensure that no excess water will accumulate along the walls. You may bury the pipe into a flower bed. Dig the flower bed down about 24 inches, fill the hole with 6 inches of gravel, lay the pipe into the gravel, cover the pipe with 6 inches of gravel, and then finish with dirt sloped away from the foundation. This will ensure proper drainage of the roof water.
Install rain gutters on the overhangs of the house. Add gutter extension pipe to the ends of the gutter and channel the water away from the basement walls.
For new construction, the outside walls of the basement should be coated with a roll-on tar and then covered with a 1-inch rigid insulation. This will prevent water infiltration and moisture buildup. Make sure that the tar covers the wall and the joint between the wall and the footer.
If the basement has already been constructed and you are having water problems, use Dry-Loc, a white paint sealer, to paint onto the interior walls of the basement. This won't stop the water from coming into the wall, but it will slow it from coming into the basement interior.