Newspaper
Protect foundation, keep water away from house
The Arizona Republic
We’re lucky to live in a state where we don’t have to worry about tornadoes, hurricanes or earthquakes—at least not too often. In Arizona, our most worrisome natural disaster is our soil, which can cause problems with the foundations of our homes.We’re also lucky that most of the problems caused by bad soil can be repaired. Still, avoiding the costly problems is easier than fixing them, so it’s a good idea to know what you’re dealing with if you own or plan to buy a home.
My friend Curt Peterson, a geotechnical engineer in Chandler, says a lot of soil-related problems arise because homeowners assume living in a dry climate means the soil is dry, sandy and stable—so they don’t think twice about planting and watering near the house. But in many areas of the state, the soil has lots of clay in it, which means it’s neither sandy nor stable. In fact, clay-based soil expands when it gets wet and shrinks when it dries out again.
Soil is moisture-sensitive, so as long as it’s dry, there’s no problem. But soil is only dry when there’s no rain, when you’re not watering your lawn or garden too close to the house and when no water is running from your neighbor’s yard into yours.
But as soon as that moisture fluctuates—like during a heavy monsoon storm or if your next-door neighbor decides to plant a yard full of thirsty greenery—the problem begins. When an expansive soil like clay comes in contact with water, it expands, causing the soil particles to push upward. If that heaving happens right under your house, it can damage your foundation.
In fact, the Association of Environmental & Engineering Geologists estimates that expansive soil is among the most expensive geologic hazards and causes $300 million in damages a year to homes.
Some of the problems associated with expansive soils: foundation cracks; cracks in floor slabs and walls; jammed doors and windows, ruptured pipes and cracks in sidewalks and roads.
The best cure: As with everything, it’s prevention. Keep water away from your house to keep the soil dry. The most drastic cure: You might have to get your damaged foundation repaired and replace the expansive soil with a non-expansive alternative. Sound expensive? It is.
Not all soil in Arizona is expansive. Some is collapsible—which means it’s loose and dry—and will collapse and compact when it gets wet. This kind of soil can cause your home to settle rather than to heave, but the symptoms are similar to the heaving brought on by expansive soils: cracked foundations, floors and walls.
Still, not all Arizona homes suffer symptoms from expansive or collapsible soil. Peterson notes that in a subdivision of 500 or so homes, maybe five or six will have an issue. That’s because much of our housing—especially in the Valley--sits on one-time farmland, which for years was irrigated and then dried out and then wet again—which removed some of the soil’s potential to expand and shrink.
If you suspect the cracks around your windows and doors are bigger and more numerous than normal, it might be a good idea to consult with an engineer who can evaluate the soil on your property and determine if you need to take drastic measures. If you’re lucky, the pro will tell you the same thing I’m saying: Keep water away from your house. The dryer the soil is, the fewer problems you’ll ever see.
For more do-it-yourself tips, go to rosieonthehouse.com. Rosie 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 KTAR-FM (92.3) in Phoenix, KQNA-AM (1130) in Prescott and KAZM-AM (780) in Sedona, and KNST-AM (790) in Tucson.
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