How to Dry a Wet Basement
Chances are, you can do it without paying a contractor
Solving basement water problems isn’t exactly easy. Diagnosis can be tricky, there are often multiple causes and most solutions aren’t guaranteed. On the other hand, some of the most effective cures are also the simplest. So before you call in a contractor, do your own detective work and try some easy fixes.
Multiple moisture sources
Before you can tackle water problems, you have to know where the water is coming from.
- Rain and snow If water shows up after a heavy rainfall or snow melt, your first strategy is to channel water away from the foundation by sloping the soil and extending downspouts.
- Groundwater Rainfall and snow melt may completely saturate the soil around your basement or raise the water table above your basement floor. Sealing leaks in walls and floors and coating them with waterproofing may solve the problem. Or you may need drain tile and a sump pump.
- High humidity Moisture carried by humid air condenses on anything cold, forming droplets and drips. Most condensation occurs on walls and floors, but it can also form on pipes and ductwork. To lower the humidity, run a dehumidifier and use the exhaust fan in a basement bathroom. Insulating cool walls and pipes also cuts condensation.
- Leaky plumbing Plumbing leaks can imitate seepage through walls and floors. After evaporating, water from leaks can contribute to condensation. The solution is simple: Fix the leaks.
Don’t get fooled by condensation
Condensation on walls and floors makes them wet and might make you think water is seeping in from outside. So here’s a simple test: Tape aluminum foil to your basement wall and inspect it a few days later. Moisture on the outside of the foil is condensation. Moisture behind the foil is coming through from outside.
Insulate walls
Aside from saving energy, properly insulated walls drastically reduce condensation. There are several good ways to insulate walls, including the method shown here. But don’t take this step until after you’ve stopped outside water from entering—moisture trapped behind insulation feeds mold.
Insulate pipes
Cover cold water pipes with insulation to prevent condensation. Foam pipe insulation is inexpensive and easy to install. Insulating the hot water pipes won’t help to dry up your basement, though it may save energy.
Seal the dryer vent
A leaky dryer vent allows water vapor from your laundry to become condensation on your walls. Seal the joints with foil tape. Don’t just use duct tape; it’ll eventually fall off.
Extend downspouts
Make sure your downspouts dump water at least 6 ft. from the foundation. If you don’t have gutters, consider adding them. The rainwater load from your roof is enormous, and channeling that water away from your basement is an effective way to reduce or eliminate incoming water.
Patch the walls
Holes and cracks let water seep in. Plugging them probably won’t solve basement-leaking problems, but it’ll help. Hydraulic cement (a powder that you mix with water) is the perfect filler for this job. Chisel out any loose material before you fill cracks or holes.
Waterproof the walls
Basement waterproofing goes on like paint and is an easy DIY project. In order to bond well, it must be applied to bare masonry, not over existing paint. And don’t skimp on the coating; applying it too thin is a common mistake.
Slope away from the foundation
Soil or pavement should slope away from the foundation for at least 6 ft. In many cases, this is the most practical way to stop snow melt and rainwater. A slope covered with plastic sheeting and decorative rock is even better. If you add landscape edging, make sure it doesn’t trap water.
If all else fails… install a drainage system
Adding drain tile and a sump pump is a major project that costs thousands of dollars, so it’s smart to try other approaches first. But when other cures for incoming water fail, a drainage system is the way to go. If properly installed, it’s a sure solution. Most systems are installed inside the foundation walls, though pros occasionally install them from outside by trenching around the house.