Basement Floor Waterproofing Methods


Why is basement floor waterproofing so often overlooked, when if it was done when the basement was built, there would be fewer problems with seepage and flooding? Basements are often thought of as just places for storage that have concrete floors and walls where you can store old toys, tools and other stuff. Now, people realize the potential of this space for something much more such as extra living space, family rooms and bedrooms.

Many homeowners go years without a water problem and then develop one due to the existing sub-floor and sub-surface drains clogging with mud.

If water from the roof is not directed far enough away from the foundation, then the soil becomes too saturated. As the home settles, walls crack, protective coatings applied to the exterior biodegrades and drainage systems fill up with silt. All of these problems can lead to leakage in the basement. Flowing ground water enters through cracks or other openings in the foundation; moisture in saturated soil enters through solid masonry (as well as through cracks and other openings) because of the natural pressure the soil exerts against the foundation. The higher the level of water, the greater the pressure. In turn this water, under increased pressure, seeks entry through cracks and crevices in the walls and floors, and concrete is no match for water pressure. The result is a flooded crawlspace or basement.

Pressure relief systems are a good way to prevent hydrostatic water from entering your home. However when the electricity goes out, most likely during a rainstorm, primary pumps cannot work. Over time this pressure increases until the moisture is literally pushed through the floor or wall (often called “bleeding”). Usually you’ll find seepage in corners or in joints where the wall meets the floor.

If water seems to be coming in from an isolated area, installing a sump pump below floor level can lower the water table and underground hydrostatic pressure in that area. However, concrete is porous and allows water vapor to pass through. This moisture makes it feel even colder, causes carpet or other floor covering to rot, allows mold to grow, and causes the basement to smell musty.

One solution is to use one of the high-grade sealants that are available on the market for the home-owner. These can often be painted, rolled or sprayed on. A typical project might involve:

– preparing the floor by removing crumbly or loose material
– making sure the basement floor is as dry as possible, hiring large fans or heaters if necessary
– making sure wall/floor junctions are sealed
– filling any particularly noticeable cracks or joints
– priming the floor if the product requires use of a primer
– top-coating floor with the final product, using 2 or 3 coats as appropriate

With a good product you will have a waterproofed basement floor that should last for a number of years. There are sealants on the market such as PermaFlex which offer complete, permanent basement floor waterproofing. Quoted as being “the only indoor waterproofing system that completely seals any basement floor permanently, no matter how wet or deteriorated” seems a good, easy system that costs a few hundred dollars as opposed to thousands for considerable manual work, pumps and pipes.


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