Foundation Drainage Specs

Yard Slope

• One of the major reasons for absorption of water into a home's foundation concerns the slope of the yard or grounds surrounding the perimeter of the home. This includes soil, concrete and blacktop surfaces. Often, the back fill near the foundation was improperly compacted. This results in the ground's settling and creates a depression for the accumulation of water. In addition, rainwater and melting snow from the roof produce large amounts of water, which overwhelms the foundation's drainage system.

  To solve this problem, build up the soil around the foundation and slope the ground within 10 feet of the home in a downward direction. Make the slope a minimum of 6 inches. Add soil with a clay-like consistency in 6-inch layers. Do not add mulch or loose dirt. Pack the material before adding the next layer. Make sure to slope the ground away from the foundation.

Sump Pump

• Many homeowners, builders and remodeling contractors choose sump pump systems for interior foundation drainage solutions in basements and crawl spaces. The system gathers excess water into a basin. A mechanical, tethered or electronic switch signals a float in the pump that the water in the basin has reached a certain level. The system automatically starts and expels the water to a public sewer system or to a spot at least 10 feet outside the home's foundation walls. Sump pumps should have a high-quality dual or backup switch. Most system failures usually result from poor switches. The sump pump must also be the appropriate size for the area to be covered.

Waterproofing

• Waterproofing refers to a common method of repair for an existing home or for new construction. It involves digging a trench around the perimeter of the foundation, spraying a polymer-based sealer on the foundation walls and embedding a membrane sheet into the sealer. This solution waterproofs the foundation wall and guides the runoff water into a 4- to 6-inch perforated drainpipe. Cover the drainpipe with a wrap and clean gravel. Back-fill the trench and slope it away from the wall.

Drain Tile

• This method of foundation drainage, sometimes called a French drain, requires the installation of drain tiles around the footing of the foundation or crawl space walls. The tile surface is below the concrete slab of a foundation or dirt floor of the crawl space and connects to drainage pipes. Wrap the pipes in fabric cloth and cover them with 1/2 inch to 3/4 inch of washed gravel. The fabric prevents the pipes from becoming contaminated with the gravel. Slope the pipes to discharge to a location a minimum of 10 feet outside the building and away from the foundation. Some installers connect the tiles to a sump pump.