Housing...Inside and Out

July 31, 1998
Inspect Your House Foundation

This time of year is the best time to inspect the exterior and interior sides of foundation walls for cracks. If any cracks are located, determine the source and make repairs to prevent water seepage.

Cracks can be caused by exterior water placing pressure on the walls or floors, by soil settlement under the foundation footing, by expansion or contraction due to weather changes, or by the use of poor quality mortar in the mortar joints. Most repairs will need to be done by a professional.

Also check the crawl space walls and floors for signs of dampness or water stains. Determine the source of the problem. Moisture problems can be caused by condensation, as well as by exterior water pressure forcing moisture through the walls and the floors. Excess condensation can be controlled by lowering the humidity level in the crawl space area.

Proper gutter and downspout construction and grading the area around the house so it slopes gently away in all directions should help. All low pockets or places where water could collect should be filled. When adding fill, maintain a distance of eight inches between the exterior grade level and the bottom course of wood or metal siding.

While inspecting the foundation, take special notice of wooden support members and floor framing for rot/decay, termites or other damage from wood-destroying pests. Pay special attention to the bases and areas where wooden members contact the foundation. If water decay is in the early stages, the area should be kept dry to prevent further damage.

If the wooden members are weakened by rot, they should be replaced with preservative treated materials after the source of the problem is eliminated. This is usually a job for a professional. If the structural members have been damaged by termites/pests, contact a professional to have the area chemically treated with an insecticide.

Inspect the vents and the crawl space area to make sure that the screen or wire mesh covering is secure and in good repair.

  • Also inspect the plastic paper barrier on the crawl space floor to be sure that overlapped seams are sealed and that no holes are apparent. If necessary, repair with duct tape.


Written by Dr. Francis Graham (Retired)

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