When cracks and leaks show up, you’ve already created or ignored problems that damage foundations, says Stan Gatland, manager of CertainTeed’s building science technology department.
Here are mistakes that can cause foundation woes and, if unresolved, can make matters worse.
1. Grading Gaffes
Poor soil excavation can direct water toward the base of your house and through foundation walls. Make sure your yard is graded at least 6 inches in 10 feet so soil slopes away from your house.
How do you check the slope? Use a level. Put one end where the ground meets your foundation wall, and level the tool. Measure the space from the other end of the level to the ground. If you use a 2-foot level, multiply your findings by five. Say you measure a 2-inch gap. That means over 10 feet, you’ll have a slope of about 10 inches — good enough. If there’s no space, you need to create slope.
By the way, 10 feet is enough to move water away from your foundation, even if the soil after that distance slopes back up the other way.
You may have to build up a berm, dig a trench, or install a French drain to funnel rainwater and runoff away from your home. Also, be careful when you apply mulch on foundation plants. Make sure that slopes away from your home, too.
2. Downspout Downer
Downspouts should direct rain and roof runoff away from your house. But if you don’t extend the downspout 5 to 10 feet away from the house, you’ll dump water on your foundation. You can buy extenders from plain ($15) to fancy ($30). Or bury a long downspout diverter underground and drain the water to the curb, a storm drain, or to a spot in your yard where the water will percolate into the soil.
3. Water Woes
Avoid letting the soil around your house completely dry out and shrink during a long dry spell. The next big rain could soak the soil, making it expand dramatically and putting stress on your foundation walls. In drought, run a soaker hose around your house at least 6 inches from the foundation and 3 inches under the soil. That should help quiet soil contraction and expansion.
4. Root Riots
Tree and shrub roots can compete with your soil for moisture during drought, causing your foundation to settle and sink unevenly. When that happens, drywall can crack and windows and doors will stick in their frames.
To prevent a war for water, plant deep-rooted trees and shrubs away from the house. If the branches touch the house, the tree is too close.