If your summertime nemesis is a damp, smelly basement, it’s time to tackle the underlying issues, according to the Environmental Protection Agency (EPA). Whether the source of your problem is a water leak or high humidity, the result can be mold, mildew, or other biological growth. And, depending on how severe the problem is, a wet basement can lead to rotting, structural damage, premature paint failure and a variety of health problems.
A wet basement can be caused by:
- Water seeping into your house from the outside through a leak in the foundation, or small gaps around windows or doors
- Water leaks inside your house from a leaking water pipe, toilet, shower or bathtub
- High indoor humidity caused by normal activities of everyday living, such as showering, cooking, and drying clothes
- Moisture migrating through a concrete foundation
- Condensation on the cold concrete walls and floors during humid months
Prescription checklist
The EPA suggests these steps in diagnosing your problem.
- Locating the source of the moisture. Below a bathroom? Ceiling? Corners? Where the problem occurs can lead to what is causing the problem. If the problem is localized (a spot on the ceiling, wall or corner it is possibly caused by a water leak. If the problem is in a large area, like a whole wall or room, then it might be caused by humidity). See below for steps to fixing leaks or humidity problems.
- If you suspect a mold problem consult EPA’s Brief Guide to Mold in Your Home for more information.
- If you plan to remodel your basement, it is important to control moisture problems before doing anything else. Find information on this EPA site.
Steps to stopping water leaks
- If a leaking pipe or appliance is the source of your problem, have it fixed first.
- If you have standing water on the floor of your basement after a heavy rain then it is likely from a leak in the foundation.
- Clean rain gutter and redirect downspout runoff away from the foundation.
- Make sure the ground around the house slopes away from the foundation. If necessary, re-grade so the ground does slopes away.
- If you have a sump pump, make sure it is working properly.
- If you have water stains on the ceiling or wall under or near a bathroom it could be a leak from a water pipe, toilet, bathtub or shower. Hire a plumber to repair the leak.
- If the leak has caused substantial water damage or mold you will want to hire a contractor who specializes in mold remediation and water damage repairs.
Reducing indoor humidity
If your water problem is caused by humidity rather than leaks, take these steps:
- If your basement has a dirt floor, cover the floor completely with plastic to slow down water vapor coming through the soil.
- Use ventilation fans in kitchens and baths to control moisture. Check to make sure ventilation fans vent directly outside. In some cases the vent fan may have been installed to vent into the attic or become disconnected or blocked. Find more information on ventilation.
- Your clothes dryer should be vented directly to the outside. Inspect the vent duct. Make sure it is attached securely to the dryer. Check that it is clear of obstructions (e.g. lint). Check for holes that leak air. If vent duct is damaged replace it with a metal duct. The vent duct should be cleaned at least once a year. The Consumer Products Safety Commission additional safety tips for dryer vents.
- Ask a heating and cooling contractor to check your heating and cooling system to make sure it is sized and operating properly to remove humidity. If your system is too big or the airflow incorrect your air conditioner will not remove humidity like it should. Also, ask the contractor to check your duct system for air leaks, and proper size and air flow to each room. For more details on sealing to prevent high humidity levels in your home and sealing ductwork.
- During hot humid months, using a dehumidifier in the basement can reduce condensation on the walls. This may work better after you’ve sealed air and duct leaks to reduce the amount of humid outdoor air you are bringing into the basement.
- Running an air conditioner can also help remove humidity from your home.
More information about sump pumps
More information about dehumidifiers