How to Stop Crawl Space Leaks

Discovering leaks in your crawl space is disheartening. You start to worry about the integrity of your foundation, the safety of your home, and the expense that is going to be involved in the repair. While professional repairs are the most common method of solving this problem, it is actually easy to locate and eliminate crawl space leaks with a little bit of effort and the ambition to handle a weekend project with your friends.

Locating the Leak

  1. Look at the area from the outside and identify any potential problem areas, such as where cracks have formed, where pipes go through or under, or other areas where the water may be getting in.

  2. Go inside the crawl space and locate the problem areas. With a friend using a garden hose at full blast from the outside, check the possible transfer of water, one location at a time.

  3. If there has been recent rainfall, you can also spend the afternoon in the crawl space looking for areas of accumulation, they should be easy to spot. Use a high-powered shop light to aid you in this. Look for the area of the crawl space wall or floor where the concrete is darker, which indicates the presence of water. Also check the low spots of the crawl space. Look for waterlines or rings of silt. Once you have found a "ponding" area, follow the erosion patterns in the soil back to where the water first entered.

Eliminating the Leak

  1. Excavate the area around the leak location on the exterior of the house with a shovel. Make sure the area that you excavate is large enough to work in and that it encompasses the entire leak area.

  2. Cover the leak area using ready mixed concrete and a trowel. Allow it to dry completely, and then place another light layer of cement over the first, and smooth a layer of crawl space liner onto the cement. This will ensure a full sealing of the leak.

  3. Seal any opening around pipes and conduits with a heavy application of waterproof silicon sealant.

  4. Drill a 1½-inch hole, and place a PVC joiner in an area above the ground line but within the crawl space headroom. Seal around the joiner and allow it to set until fully dry.

  5. Install a sump pump by digging a hole in the lowest area of the crawlspace that is at least 22 inches deep and at least 24 inches wide. Place a sump pump liner into the hole and use the dirt you have dug out to fill in other low areas, and try to smooth the ground if you can so that water will flow to your new sump hole.

  6. Seat your sump pump into the hole and make sure you install a check valve near the pump on the discharge line.

  7. Run your sump discharge line out of the crawl space and through the hole you formed earlier by connecting the pipe to the joiner.

  8. Run the PVC piping away from the house to a location in your yard where you have a natural downgrade. Dig out for the line using a hoe, and after placing it, fill it back over, making sure not to cover the opening at the end.

  9. Dig a trench about 6 inches deep around the outer perimeter of the crawl space using a short-handled hoe. Line the interior side of the trench with the crawl space liner, but not the trench bottom.

  10. Make perforations on the top half of the 1½-inch PVC pipe with your drill, using the 1/8-inch drill bit.

  11. Place the perforated pipe into the trench and cover with gravel to the level of the floor. The end of this pipe should be next to the sump pump liner so that the water will come out of the pipe and enter one of the holes in the liner.

  12. Line the walls and the floor of your crawl space with the crawl space liner according to the directions that come with it. When installing on the exterior wall, make sure you lay the liner over the "gravel trench" so that the water that might get in flows under the plastic and into the trench. Tuck the liner between the sump pump liner and the dirt to make sure the air tight cover is in place and the drain sponge is exposed.

  13. Connect the flexible rubber hose to the discharge line and run the power cord to an outlet.

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