Use Plants to Keep Foundation Stable in Summer During Drought

Austin American Statesman

Key Points:

  • Use plants and mulch to help keep foundation stable this summer.
  • Even watering is the key to protecting a home's foundation.


If this summer turns out to be as dry as climatologists think it might be, Douglas Plauché is going to be a busy man. As owner of Douglas Foundation Repair in Austin and San Antonio, it's his job to stabilize foundations that shift and crack when the parched ground shrinks and pulls away from the concrete.

Once the dry weather sets in, homeowners often water the base of their houses to try to keep the soil around it moist and prevent the concrete from shifting around. But unless you are watering consistently and frequently, you might be doing more harm than good, Plauché says.

"Your house is a vessel floating on the ground here. If you're hydrating one side and not the other, it will get out of balance," Plauché says. That's when cracks start appearing on walls inside the house and even outside the house, on sidewalks and driveways. "Most people only go out and start paying attention to things when it's dry," he says. "They'll go outside on a Saturday morning with a cup of coffee in their hand, see some cracks, turn on the soaker hose and go back in the house for three hours." Too much water underneath the foundation will make the dirt turn to "goo," and watering too much and too infrequently will make the foundation even more unstable, Plauché says. Both concrete slabs and pier-and-beam foundations have similar issues, but residents need to be especially careful to water evenly around the latter. Piers are like arms that can tilt individually, he says. Maintaining a solid foundation, from Plauché's perspective, means watering the foundation with a soaker hose every day for 20 minutes. (Stage 1 water restrictions are currently in place for Austin residents, which means residents can only water with a soaker hose on designated days. Go to for more information.) How much you need to water the ground around your foundation can vary depending on which side of the house gets the most sun, which has the most shade and how much rain, if any, has fallen. "You have to pay a lot of attention at first," he says. Use a hose with a timer, he says, or else you'll eventually leave it on all night accidentally. "But once you figure out how much water your particular house and soil need, it's easier." Gardeners have a big advantage when it comes to foundations because they are already outside their house, watching how things are growing and changing throughout the year. "Those folks are at home taking care of their home, looking at things. They take better care of their homes because they pay attention."

Even nongardeners can take a cue from their green-thumbed friends. Instead of watering the outer edge of the foundation and whatever grass, weeds or dirt that happens to be next to it, you can plant certain shrubs and ground cover that will hold moisture and prevent the soil from undergoing such severe expansion and contraction, which is typical of the clay-filled soil we have in much of Central Texas. Even in areas with thin, rocky soil, particularly west of Austin, it's important to monitor the ground around your house.

Don't plant trees or other plants that have extremely deep or penetrating roots next to structures, because the roots will go as deep as necessary, even under the house, to find water, and that will disrupt the foundation. Daphne Richards, horticulture agent for the Travis County office of the Texas AgriLife Extension Service, says that small shrubs, plants and flowers a few feet away from the base of the house look nice, and to keep them healthy, you'll have to remember to water them frequently, which will help your house, too.

When watered, shrubs such as loropetalum, elaeagnus, pittosporum and even boxwoods will help keep the ground moist, Richards says, but you'll have to keep them trimmed so they don't grow large enough to block a window or bump up against the house. Plants and grasses that help prevent soil erosion have root systems that will hold in moisture, too. You can simply mulch the area, but the problem with creating a consistently moist environment around your house, especially with mulch and woody shrubs, is that it can attract termites, says Roger Gold, a professor of entomology at Texas A&M University.

"If the soil or mulch is up too high or the termites tunnel up the wall, then they will gain entrance," Gold says. Leave 4 to 6 inches between the mulch and the line where the home's foundation ends and the flooring begins. This will prevent water from soaking directly into the walls and will help keep termites at bay.

You can treat the mulch with termiticide, but the best way to keep your house safe from both foundation problems and termites is to actively monitor the area around the base of your house. You'll be able to see when the earth starts to get dry and pull away from the foundation and if termites take up residence in your beds. (If you see termites or the tunnels they make from the ground up the side of the house, call a professional exterminator. Gold doesn't recommend treating them yourself.)

"There's no magic rule," Gold says. If you keep the area around your house completely dry, you'll have foundation problems. If you keep it soaking wet, you'll have termite problems. The key is keeping a close watch on what's going on in your yard and in your house.; 912-2504

posted: Wednesday, April 13, 2011