5 Solutions for Wet Basements

Water damaged basement
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For many homeowners, a basement is not just a nice thing to have, it is an essential living space. And there is no greater obstacle to homeowners finishing their basements than the looming specter of a wet basement.

A wet, damp, or flooded basement will instantly cancel all of your good basement finishing work. With the floors ruined, drywall waterlogged, and insulation soaked, you have hundreds, usually thousands, of dollars worth of repairs ahead of you.

But the problem of wet basements can be solved. Do you have a basement that gets wet in certain areas after a hard rain? Or does your basement develop small pools of water that seem to come from nowhere? Many of these common problems have solutions that can help you turn your basement into a habitable living space.

Water Is Leaking Within the Basement

When a homeowner sees water in the basement, the immediate thought is that it is coming through foundation walls. For this reason, it's easy to be blind to internal causes. It pays to think inside the box, and that has a literal meaning: within the house envelope. First, you can look at anything in the basement that holds or produces water.

  • Washing machines
  • Sump pumps
  • Water heaters
  • Plumbing pipes above head running through floor joists
  • Basement bathroom sinks, toilets, or showers
  • Basement areas that have dishwashers or bathing facilities on the floor above
  • Wet bars

If you have ruled out internal water-producing sources for the water in the basement, then you can begin to look at external sources.

Water Is Leaking Through a Crack

Cracks in the foundation wall are the classic culprit for water leakage in the basement. Not all cracks result in leaks, though. Look for the obvious sign (water) or the less obvious sign: calcium efflorescence left over after water has evaporated.

As counter-intuitive as it may seem, to fix the problem you will need to chip along the crack in order to widen it to about 3/4-inch and then deepen it to about 1/2-inch. This is the only way to get the hydraulic cement to adequately hold in place. After widening, use elastomeric concrete sealant in the crack.

Concrete Floor Slab Is Leaking

Water leaks in a basement can come up through a floor, as well. Concrete floor slabs are as prone to cracking and leaking as are other areas of the basement. Tree roots may work under the slab and force the slab up, cracking it. Groundwater can seep upward through cracks in your concrete floor slab.

To fix this issue, widen and deepen the crack to about 1/4-inch to 1/2-inch wide and deep. Make sure the edges of the prepared crack do not form a "V" shape; otherwise, your sealant will not properly stick. Instead, chip sides straight down or, better yet, outwards at the bottom to form a tomahawk shape.

Fill the crack with an elastomeric concrete sealant. Elastomeric sealant is not the same as silicone or painter's caulk, the type you might use for windows or bathroom sinks. Elastomeric sealant readily sticks to concrete and masonry and easily shrugs off temperature ranges from -30 F up to 100 F.

The Joint Between the Wall and Floor Slab Is Leaking

When it comes to holding back water, any kind of joint spells trouble. Because the wall and floor can move at independent rates, cracks may occur where the two join.

Water leaking in this area may be the result of surface water percolating downward. Installing a drainage system may fix this problem. If the crack is less than 1/4-inch, chip away the loose areas with your cold chisel and hammer. Sweep out loose particles. Apply the elastomeric sealant into the crack.

If the crack is more than 1/4-inch, sealant only likely will not solve the issue. In this case, consult a foundation repair company.

Water Is Leaking Around a Window

Windows in basements provide rare natural light in an otherwise dark place. But windows also provide leakage points for water from the outside trying to get inside.

When water is leaking around a basement window, install a window well liner and window well cover. Dig out a window well and place a liner inside this hole to prevent dirt and moisture from infiltrating the hole. A nice bonus to this project is a window well cover to seal up the entire space.