During periods of severe drought (as has been the case for the past few weeks in North Texas), the clay soils shrink and decrease in size. As the soil dries and shrinks, gaps develop along the side of the foundation and giant cracks develop in the lawn. In this blog I will explain how you can prevent this from happening or reverse the process. I will refer to an article by Dr. William Johnson, (Ref 2) a horticulturist, published in The Galveston Daily County News (Ref 1).
Johnson starts his paper by stressing that the practice of just watering the front yard to keep it lush (for the neighbors and homeowner association enforcement folks) while letting the backyard go dry, should be avoided. This results in portions of the foundation being wet and expanded while other parts are dry and contracted. This can lead to cracking of the exterior brick veneer and to doors of rooms, closets, or cabinets coming out of alignment and becoming difficult to open or close. Cracks might also develop in drywall and in tile floors.
Johnson starts his paper by stressing that the practice of just watering the front yard to keep it lush (for the neighbors and homeowner association enforcement folks) while letting the backyard go dry, should be avoided. This results in portions of the foundation being wet and expanded while other parts are dry and contracted. This can lead to cracking of the exterior brick veneer and to doors of rooms, closets, or cabinets coming out of alignment and becoming difficult to open or close. Cracks might also develop in drywall and in tile floors.
You can protect the foundation by keeping the soil adjacent to the foundation at a fairly consistent moisture level throughout the year. To do this, water the soil evenly and frequently around the entire foundation during extended dry periods. This should prevent a gap from opening between the soil and foundation edge. If you have a sprinkler system in the landscape beds around the perimeter of your home, use it on a daily basis at night. The goal is to get the soil moist so that it is damp to the touch and you can mold it into a ball.
If you don’t have a sprinkler system around the perimeter of your home, place a soaker hose or series of connected soaker hoses around the entire foundation. Lay the soaker hose 6-8 inches away from the foundation. Do not turn the faucet handle to the fully open position when watering by soaker hose — the goal is to apply only enough water so that the soil can absorb the water without runoff or puddling.
Do not be tempted to run water from a hose directly into gaps and cracks along the foundation as the heavy flow of water can travel along the cracks for several feet in all directions washing the soil away from the foundation. In addition this can cause sudden expansion of the clay soil which will lead to foundation movement.
You may be wondering how often you should apply water along the foundation. The key is to maintain a slow flow of water. This might require watering every day to start and perhaps every two to three days when soil moisture levels have been stabilized or the drought has ended. You should apply no more than a 1/4” of water per hour. If you have a sprinkler system around your foundation take a saucer and place it about 18” from one of the sprinkler heads. Run the sprinkler and time how long it takes to get a ¼” of water in the saucer. That will be the run time for each watering session. Set your sprinkle to run for that time and then wait at least an hour before you run it again. Repeat this once or twice a night until the soils around the foundation are damp.
Finally, if you have landscape beds around your foundation, apply a 3 to 4-inch layer of mulch over the top soil. Mulch not only keeps the weeds down, it also helps prevent dramatic loss of moisture through evaporation.
Do not apply mulch above the slab grade wall on to the brick line or exterior siding as you will be inviting trouble from insects such as termites and ants. Also, moisture from the mulch can migrate through to the wall cavity. Even though gaps along the foundation become most noticeable during extreme droughts, homeowners should monitor their foundations throughout the year to keep constant moisture levels around the foundation.
Finally, if you are thinking of buying a house and you see the conditions discussed here and in my last blog do not freak out! The vast majority of these conditions can be cured by applying water and if there are cracks they will stop getting worse and in most cases close back up again.
If you do not have a sprinkler system and are interested in a DIY solution send me an email requesting my irrigation system design. It is free and is based on parts which are readily obtainable from Home Depot. The design provides timed zones and individual watering times for each zone.
Reference:
1: The Galveston County Daily News, August 3, Online edition http://galvestondailynews.com/story/246654
2: Dr. William Johnson is a horticulturist with the Galveston County Office of Texas AgriLife Extension Service, The Texas A&M System. Visit his Web site at
http://aggie-horticulture.tamu.edu/galveston
3. Water Efficency advice for home owners http://www.epa.gov/WaterSense/pubs/res.html
4. Outdoor Summer Watering Schedule http://www.friscotexas.gov/departments/publicworks/water/Pages/default.aspx
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