Solving Basement Water Problems

Guide to solving basement water problems, including diagrams, tips on where to look for water leaks, optimum drainage and ways to keep water out of the home basement.

| May/June 1986


Figure 1: Idealized basement to keep out water leaks.


Laid-up masonry basement walls on concrete footers are sturdy, economical, and comparatively simple to erect. Combine those attributes with the fact that they allow great design flexibility, and you've got a pretty fair explanation of why concrete block basement walls are so common. Unfortunately, water leaks all too often seem to be another standard feature of block basement walls.

Solving Basement Water Problems

Once you've determined where the water in your basement is coming from, follow the key numbers to find solutions appropriate to your problems. Try the lowest-numbered solutions first, and move on to more drastic measures — such as digging up the foundation and installing a drain — only if the easier approaches fail.

[1] Landscaping

The simplest, least expensive way to solve surface water problems is to landscape the area around your house to prevent surface water from saturating the soil next to the basement walls. The ground should slope downward from the house at least 4 inches in the first 6 feet, and no shrubs or trees should be planted closer than 3 feet from the walls.

In a location where the terrain itself slopes significantly, it may not be practical to grade the entire area around the house to reroute drainage. In such a case, a shallow valley can be cut about 12 feet out from the wall to catch runoff and route it around the house. This depression need not be severe; a 1-foot-deep trench with gentle sides will channel a great deal of water and will still be easy to mow.

[2] Water-shedding layer

If you're forced to strip back more than a few inches of topsoil to achieve the proper grading, it's probably worthwhile to continue digging down to a point about a foot below the previous grade, and to then lay down a sheet of 10-mil polyethylene before replacing the soil. This barrier will usher water away from the basement walls.

[3] Redo sidewalks or porches that are poorly sloped or loose to the foundation.

It may sound drastic to rip up a sidewalk or porch and replace it, but this is still a much easier undertaking than uprooting the house's footings. Break up the old concrete, and dig down 4 inches below what was the level of the underside of the slab. Lay a 4-inch layer of gravel for drainage, and set the forms for the new concrete so that the new slab or sidewalk will slope away from the foundation wall about 1 inch in 10 feet. Use a watertight expansion joint between the new concrete and the foundation wall.

5/4/2016 8:31:22 AM

Add gutters and leaders to the house, unless ground water is entering the basement, adding gutters should do most of the water removal. Make sure to use splash blocks at the leaders for routing the water. Get at least 2 prices from contractors that were recommended to you.

3/19/2016 4:02:07 AM

Like a bolt from the blue, I found cracks on my basement walls. Thanks God my dad fixed it with these basement waterproofing products Has anybody used it for solving same problems?

4/13/2015 1:16:05 PM

I never realized that it was so important to plant trees far away from the basement. I guess it makes sense because you don't want it to grow roots that break the concrete over time. If there are trees or shrubs that have grown naturally near the basement, is it important to have them removed? I just want to make sure that I don't have any waterproofing issues over time. Thanks for sharing your tips with us.

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