Wet Basements and Crawlspaces: A Primer

The Signs of Water Problems

A few signs of water problems to look for, other than the obvious pooling water sitting on the ground include:

• Rust at the base of heating or plumbing fixtures
• Stains, discoloration, or decay on wood posts, paneling, walls, or sheetrock walls
• Damaged floor tiles or carpet
• Apparent mold/mildew on walls or surfaces of storage objects
• Efflorescence on foundation walls
• Rotting wood
• Water stains on the bottoms of storage items such as furniture and boxes
• Cracked or bulging foundation walls or floors
• Insects
• Musty odors
• Damaged, leaking plumbing fixtures

How Do Water Problems develop?

Direct Leakage: Water may flow through obvious openings, through unnoticed cracks or through the intersection where the floor meets the wall. Poor ground surface drainage outside the house is the most frequent cause of this kind of water penetration. Occasionally, water supply pipes and pipes in crawlspaces, which are in poor condition may cause leakage. High water tables or underground aquifers are sometimes responsible.

Seepage: Water can seep through the same pathways as mentioned above but at a slower rate. Some moisture seepage occurs directly through moist foundation walls and floors, especially in warm weather.

Condensation: Since warm air can hold more water than cool air, condensation is caused when warm, moist air moves into a cooler air space or comes in contact with a cooler object. For example, when warm interior air comes in contact with a cold surface such as metal window frames or a cold water piper, the water vapor in the air turns to liquid and collects on the colder surface.

How to Keep Water Out?

If you’ve been putting off addressing your basement or crawlspace problem because you are afraid it will be too expensive or too complex to fix, you should know that simple remedies may offer relief from the problem. Once you learn all you can about water control, you can deal with routine maintenance and care that may make the difference between a damp and dry living space.

Exterior:

1. Pitch the adjacent ground away from the house at a slope of approximately ½” to 1” per linear foot.

2. Gutters and downspouts (leaders) are important for diverting water away from foundation walls. Gutters should be cleaned and should be sloped properly down toward the downspouts. Test the underground downspouts to make sure they are not clogged or leaking toward the foundation. Put a hose down there and find the termination point, and make sure water if flowing to the final point. If the downspouts are above ground, they should extend several feet away from the house to a lower point and discharge into a splash block.

3. Stop water entry through basement windows by maintaining window wells that are at least 4” above a positive grade away from the house. Clean the window wells periodically. Plastic domes can often help keep the wells clean and free of leaves and water.

4. Remove sunken flower beds close to the foundation walls as they may retain too much water.

5. If you have basement stairwells, make sure there is a storm drain at the bottom that is kept clean and free of leaves. It also should be properly sized and designed by an architect or engineer.

6. Adjust automatic sprinkler times to reduce the amount of watering. Sprinklers near the house should be checked to ensure that water is not being sprayed against the foundation.

7. Be sure that patios, driveways and walkways slope away from the foundation. Seal cracks between foundation walls and these surfaces with caulk.

8. Trim vegetation at least one foot away from the house so the house can breathe. Remove any ivy from the exterior as well.

Interior:

1. Seal any foundation wall cracks with caulk or epoxy.

2. If the crawlspace floor is only dirt, you should install a vapor barrier. It can range from a product called “Clean Space” to sprayed in concrete to a 6 ml. polyethylene sheet that laps up onto the walls.

3. Prevent sweating or dripping from condensation by wrapping cold water pipes, well tanks and air conditioning ducts with insulation. Also, have a licensed plumber inspect your plumbing for any signs of immanent leaks and check the age and condition of your water heater to prevent leaking.

4. Use a dehumidifier that is properly sized for the given space from spring through autumn. The humidity level should never be allowed to exceed 50% and should be monitored with a separate hygrometer.

5. If there are bathrooms or laundry rooms, all vents should go to the outside.

Waterproofing:

If the above measures alone do not solve the problem, then waterproofing will become necessary. The most common system is an interior perimeter drainage system with a sump pump, however at times, exterior systems are a better solution. The key to this is having the right person do it. The two places to turn are either a professional waterproofing company that will give you a lifetime or long-term warranty in case seepage still occurs, or a civil engineer (PE) who specializes in water control, to design a system for a contractor to implement. It is strongly recommended that a contractor or plumber not be hired to do what they think needs to be done, because you will have no recourse against them if their work is ineffective. Waterproofing is expensive, but well worth the price as water is a house’s worst enemy and not only can it damage your structure and contents, but can cause dangerous mold which can in turn, cause serious health problems for you and your family.