The little bit of rain we get can cause huge problems for your home if it seeps under your foundation and causes the soil to swell. The swelling can cause your house to “heave,” which can crack the foundation. A solution: Install rain gutters and attach them to downspouts and drains that will carry rainwater far away from your home.

If you love a green lawn and lots of lush bushes and flowers against the house, you could be setting yourself up for problems with your foundation.

Northern Arizona’s expansive, clay-based soil can swell when it gets wet. That swelling can push up against your home’s foundation and cause it to “heave” — or lift higher in some places than others — and crack.

More than half of homes around the country — and more in Arizona — are built on soil that’s considered “expansive” — that is, it swells when it gets wet and shrinks when it gets dry — and about half of them will suffer some damage because of that swelling and shrinking, the U.S. Department of Agriculture reports.

Geologists estimate that soil swelling and shrinking causes more damage to homes and other buildings than hurricanes, earthquakes and floods combined during an average year.

Northern Arizona’s soil has a lot of clay content, which means it’s “expansive.” Expansive soil swells when it gets wet and shrinks when it dries out. That movement can cause your home’s foundation to move, too, and that can lead to damage like cracks.

When your house heaves, that means the part of the foundation that sits on top of the swelling soil literally rises above the rest of the foundation. When it settles, part of the foundation drops below the rest of it. This causes those cracks that you see, but it also can cause structural damage to the home that you can’t see.

The best thing you can do for your home is keep water away from it.

Here are a few tips:

• Even though we don’t get much rain, install rain gutters on your home. Attach them to downspouts, and attach the downspouts to long tubes that will divert the rainwater out into yard at least five feet away from your home. Point the drains away from the house next door so you don’t wind up causing a soil or foundation problem for your neighbors.
• Don’t plant anything within two or three feet of the foundation. The water you pour on those plants will seep under the foundation, which could cause the soil to expand.
• In fact, it’s a good practice to landscape your entire lawn with plants that require sparse watering—even if they’re not right up against the house. Any time you soak your lawn, you create the potential for water to find its way under the foundation. Water doesn’t have to hit the foundation to seep under it.


If you see large cracks around windows or doors—on the inside of outside of your home—that could be a symptom of a cracked foundation. Call a foundation specialist to evaluate the cracks and recommend a solution. Photo courtesy of Arizona Ram Jack

• An aside: Maintaining low-water vegetation is a responsible way to conserve water.
• If you must run your sprinklers, place them where they won’t spray water directly onto your house.
• Regrade your lawn if it slopes toward the house. This isn’t cheap, but it’s less expensive than having to repair a foundation that cracks because too much water has drained under it.
• If you see water ponding near your foundation, call in a foundation repair expert to recommend ways to stop it.
• Repair plumbing leaks immediately.

Even homes built on the worst kind of clay soil can escape the heaving and settling that causes foundation problems if the homeowner is diligent about keeping the soil dry.

For more do-it-yourself tips, go to rosieonthehouse.com. Rosie RomeroRosie Romero is an Arizona contractor who has been in the Arizona home building and remodeling industry for 35 years. He has a radio program from 8-11 a.m. Saturdays on KAZM (780 AM) and KQNA (1130 AM).