Wet Basement? Installing expensive interior drainage systems and sump pumps may not be necessary. These systems often just manage the problem rather than solving it. Most basement moisture problems can be solved through more effective and less expensive means.
Basements get wet when rainwater runs toward the walls of houses from roofs, yards and driveways. You need to force this water away from your home.
Start by checking and fixing your gutters. Clean them out, patch any holes and make sure they slope toward downspouts and have not come loose from the house, allowing water to fall directly to the ground next to walls. Test gutter downspouts to make sure they spill water at least 4 feet away from the house.
You can extend downspouts for less than $15 each. Gutter repairs are more expensive, but these improvements are worth the price, even if they do not fully solve your water problem.
The next step is to inspect the soil around your house and regrade it, if necessary. This is a job you may be able to do yourself, or you can call in a landscaper. The earth around your house should slope at least 1 inch per foot away from your house for about 6–8 feet. The grading should consist of fill soil with a clay content of 20–30%. Don’t use sandy soil or soil containing a lot of organic matter; it will not shed water adequately.
Before adding dirt around your foundation, rake out all old mulch, leaves and ground cover. If there is too much, they will create a shelf that catches water.
A grading solution has important advantages. It costs relatively little as dirt is fairly cheap, it requires no great skill, and it should move enough water away from your house to prevent serious harm.
If portions of your yard slope toward your house, you may have to cut a shallow ditch — or swale — to divert the water before it reaches the house. A swale is a U-shaped, shallow ditch dug perpendicular to the water flow. As with regrading, it’s a fairly simple job.
If regrading and other surface drainage improvements don’t solve the problem, more drastic — and expensive — solutions await.
For most homes, the next best approach is to waterproof the walls from the outside. To do this, a trench is dug to the depth of the footings of affected walls. Drainage pipe is installed at the bottom of the trench to collect water that seeps from above and carry it to a part of your yard away from your home or into a drainage pit. A coating and a vapor barrier are added to exterior walls. The trench is filled with soil that is tamped down, and the surface area is regraded to improve surface drainage.
Excavating and waterproofing from the outside might be more expensive than installing an interior drainage system. But Checkbook’s view is that, unlike interior systems, this will actually solve the underlying problem by diverting water away from walls, rather than simply managing water that enters the home.
If you need to hire a contractor, meet with and obtain proposals from several of them. Some landscaping companies specialize in drainage work.
Big differences exist in the quality of advice provided by basement waterproofing contractors. Checkbook’s undercover shoppers found that different companies may propose drastically different — and in some cases costly and unnecessary — solutions. Don’t let them pressure you into a decision; avoid companies that use aggressive sales tactics. Compare the guarantees offered by companies that bid on the work.
If your home was built or remodeled within the last few years, check the builder’s warranty for clauses on seepage. The builder might bear the costs of any solutions and repairs.
Kevin Brasler is executive editor of Puget Sound Consumers’ Checkbook and Checkbook.org, a nonprofit organization with a mission to help consumers get the best service and lowest prices. It is supported by consumers and takes no money from the service providers it evaluates. See Checkbook’s ratings of local basement waterproofing companies free through Nov. 5 via Checkbook.org/SeattleTimes/Wet-Basement.