First aid for leaky basements

COLUMBIA, Mo. – If your basement sprung a leak during recent intense rainfalls, you’re not alone.

Two years of drought followed by heavy autumn rainfalls created the perfect storm for leaky and flooded basements, said University of Missouri Extension state housing and environmental design specialist Michael Goldschmidt.

Calls have poured into state and local extension offices in recent weeks from homeowners seeking advice on how to stop leaks. Specialists fielded more questions, he said, than during the flood of 1993. Many areas of the state have dense clay soil that lacks the porosity for water to flow through quickly, allowing water to build up around foundations.

Goldschmidt recommends inspecting basement walls and floors to locate cracks or breaks that can turn into active water leaks. Find the source of the leak if possible. Water takes the path of least resistance. If you’ve got a small crack, water will find it and make it bigger, Goldschmidt said. Areas where walls meet are most susceptible to seepage. Check drainpipes for clogging and feel around basement windows for moisture.

Some basements are more at risk of water leaks than others. The lower your basement is in the ground, the more pressure its walls will feel from incoming water. Older houses are most vulnerable to damage because foundations settle over time.

As your first line of defense, clean your gutters and downspouts this time of year. Leaves and other debris can dam up the gutters, forcing water to spill out near the basement instead of being carried away from the home.

Flexible extenders can carry water recommended distances of 10 feet out and downhill from your home. Install French drains, which are perforated flexible drainpipes, to divert surface water away from the foundation of the house. Regrade landscaping areas if water pools there.

Goldschmidt recommends staining and sealing concrete basement floors rather than installing carpet. Carpet can absorb and trap moisture and cause mold.

Radon can make its way through cracks, so this is a good time for radon testing. And inspect your sump pumps while you are checking your basement.

It’s best to call a professional for basement problems to protect the structural integrity of your home. It is expensive, but protects what is likely your biggest investment, Goldschmidt said.

Before the professional comes, there are steps you can take to stop the flow of water temporarily. You can make temporary patches that will give you one to two years of protection.

Just remember, once you patch one crack, water will find another place to enter, he says.

Goldschmidt suggests the following:

• Waterproof silicone-based caulking can be squeezed into cracks to provide temporary relief. This works best on hairline cracks, those that a credit card will slide into.

• Another option for small cracks is to spread a thin layer of asphalt-based waterproof material onto walls with a trowel. The material is similar to roofing tar and is toxic, so Goldschmidt recommends adequate outside ventilation when using this product.

• Use a cementitious coating if the crack is 1/4 inch or larger. This resists water pressure in below-ground structures.

• Hydraulic cements such as Waterplug can be applied even when water is leaking.

Check with your local building supply or hardware store for recommended supplies. Follow manufacturer’s instructions and adhere to safety warnings.