These foundation maintenance guidelines are intended to be general in nature. If you feel your foundation is experiencing excessive movement, it is recommended that you consult with a qualified foundation repair contractor or structural engineer.
Foundation problems due to drought conditions can be minimized through proper moisture levels in the soil. Maintaining constant moisture content under slabs is a real challenge given the extremes of our Texas weather. Most of our Texas soils are highly expansive, meaning that as they absorb water, they swell, and as they lose water, they shrink. Soils tend to dry out (and shrink) during the summer and to absorb water (and swell) during the winter and spring. As the soil under a house shrinks and swells with the seasons, the house and foundation will move up and down. As long as the foundation movement is not enough to cause significant cosmetic damage, or even minor structural damage, it should not be considered a problem. In fact, some seasonal minor drywall cracks or sticking doors can almost be expected in our area.
The key to proper foundation maintenance is to be diligent in your irrigation program, but at the same time, to be sure your drainage is adequate. (Poor drainage can cause a completely different set of problems.)
Effective irrigation is best accomplished with an underground foundation watering system; automated systems that monitor soil moisture and irrigate as needed are available from several different local contactors. Soaker hoses will provide you with many of the same benefits, if utilized properly. The best way to use a soaker hose is to bury it about three inches deep, one foot from the edge of your foundation. Placing the hose a short distance from the foundation allows the water to soak into the soil evenly. An automated underground sprinkler system can be just as effective. Be sure that it waters the soil next to the foundation, and check it periodically to be sure it is working properly. And don’t neglect to water during the winter months as well, when we sometimes experience extended periods without rain.
Obviously, it is necessary to water more during hot, dry weather and less during cold, damp weather. The amount of water required to keep a foundation stable during the summer can be surprisingly large. A single large tree can remove as much as 150 gallons of water, or almost 20 cubic feet of water, from the soil each day. Shrubs and other plants can also remove large quantities of water. During persistent hot, dry weather, it may be necessary to water a foundation daily. Watering should supply enough water to keep the moisture content in the soil under the foundation constant. If the amount of water applied is only enough to keep the surface damp, the watering program will not work. Obviously, the homeowner is the only one who can weight the benefits of controlling foundation movement versus the increased size of the water bill.
During periods of drought, it is suggested to utilize your soaker hoses on an every-other-day basis, for an hour or so each time.
Water pooling against or near your foundation can result in “heaving” (where the swelled soil actually lifts the foundation above its intended elevation), or it can cause the soil under the foundation to lose its load bearing capacity, resulting in settlement. To guard against these problems, the general grade of your yard should slope gently away from the home, and roof drainage downspouts should be extended several feet away from the foundation. If the general slope of your yard cannot be easily changed, then some form of surface or below grade drainage system may be needed. Consult with a qualified foundation repair or landscape contractor to find out what will work best for your particular situation.