When water collects next to a foundation wall, or when the water table (the water level under your property) is higher than your basement floor, hydrostatic pressure can force water through cracks, joints and porous areas in concrete walls and floors and through cracked or crumbling mortar joints in masonry walls. Causes can include:
Poor construction practices.
Clogged or non-existent footing drains.
Poorly applied or nonexistent waterproofing on the foundation
Cracks through the wall.
Correcting any of these problems is a major job that requires digging out the foundation to the bottom of the footings. Though this may very well be the most permanent repair, first try the remedies that follow. If they don’t work, then you’ll have to contact a foundation engineer or contractor for a more lasting solution. CAUTION: If you see horizontal cracks in a wall that’s bowing inward, long, vertical cracks wider than 1/4 inch, or a crack that’s getting wider (measure periodically), you have a structural problem. Contact a soils or foundation engineer at once.
Roof and surface water collecting next to the foundation may be causing the dampness in your basement. Make a careful inspection outside, using the following checklist, and correct any problems you find.
Gutters and downspouts should be clear and should direct water away from the foundation.
For tips on cleaning gutters and improving drainage at downspouts, click here.
Make sure you have proper grading around the house. The ground should drop one inch per foot for the first ten feet away from the foundation walls to ensure good surface drainage.
Planting beds next to the foundation should keep water from collecting or pooling.
Window wells around basement windows should be free of debris, have good drainage, and be properly sealed at the wall.
These simple interior repairs may alleviate or cure your water problems:
Apply a coating to the wall. Most coatings are painted on, though some are plastered on with a trowel. Except for epoxy coatings, all are cement-base products with various additives. Epoxy does the best job. Look for coatings at home improvement or masonry supply centers.
Patch cracks in walls and floors with Portland or hydraulic cement patching compound. Hydraulic cement expands and dries quickly, even in wet conditions. Cracks wider than 1/8 inch should be undercut-chiseled out so the bottom of the crack is wider than the. This will prevent water pressure from popping out of the patch.
Chisel out a groove along the wall if water is entering through a floor/wall joint. Fill the groove with hydraulic or epoxy cement and cove (form in a concave shape).
Chisel out cracked mortar joints in masonry walls and fill them with hydraulic or epoxy cement.
Water that comes through cracks in a concrete floor or through the joint between the floor and wall is caused by hydrostatic pressure.
In addition to those described above, remedies include:
Installing drains under the floor.
Adding a sump pump.
Laying a new floor over a waterproof membrane placed on the old floor.