How To Waterproof Your Basement
If you are trying to figure out how to cure a wet basement, you’re probably curious about options to alleviate and solve your water predicament. To remedy wetness, it's necessary to choose the right solution for your particular problem.
First, you will need to determine if the moisture is coming from the outside, or if it's high humidity that’s condensing on the cold walls of your basement.
If you have high air humidity in your basement, use a portable dehumidifier or a whole-house humidifier system to remove the moisture from the air instead of waterproofing products.
However, if the moisture is seeping through your walls, then you'll want to consider additional exterior and interior waterproofing options (often in combination).
The best way to waterproof your basement walls is a full-scale exterior waterproofing solution. However, this can be costly.
Exterior waterproofing involves excavating around the house down to the full depth of the foundation walls and installing a waterproof coating or membrane topped by drainage panels. The drainage panels provide a path for water to flow down to an exterior French drain at the bottom of your foundation. From there, water flows by gravity — or with the aid of a sump pump — away from your foundation to another part of your property, or into a storm drain. A French drain is used to redirect water and relieve hydrostatic pressure against your foundation, while exterior waterproofing is used to protect the foundation.
Another option is to seal foundation walls from the inside of your home. There are four methods often used:
- Concrete waterproofing coatings: These thick coatings are cement-like; once dry, they adhere permanently to concrete and masonry walls. You apply the coating with a heavy brush made with Tampico bristles — a natural fiber. Swirl the brush at the final stage of application to give the wall an attractive, finished look. However, concrete waterproof coatings can’t be applied to previously painted surfaces.
- Silicate-based concrete sealers, also known as densifiers, are only suitable for walls that haven’t been painted or sealed. The sealers soak in and chemically react with ingredients in the concrete or brick, forming a hard, waterproof surface. Because these are penetrating sealers, they can’t flake off or peel, and you usually can paint over them (but check the label first). Applying a silicate-based sealer is an inexpensive and easy DIY project with a brush, roller, or sprayer.
- Waterproofing paint is an acrylic formula, not all that different from ordinary wall paint. You can apply it over painted surfaces, and paint over it once it’s cured. To apply it you will want to brush, roll, or spray it on much more thickly.
- Plastic sheets and panels are suitable for wall waterproofing only in combination with interior basement drainage systems. They don’t stop water from getting through the wall, but they do stop it from ruining things in the basement. Water that gets through the wall will run down the back of the plastic, into a floor drainage system. A sump pump is required to then move the water out of your basement.
NOTE: None of these interior products will work unless cracks and gaps are properly sealed. So make sure you fill cracks and gaps less than 1/8-inch wide with polyurethane caulk made for masonry and patch wider cracks with epoxy filler.
Source: House Logic, Waterproofing Basements