It can be found in Texas, California, Colorado and Mississippi. It causes more property damage in a typical year than hurricanes, tornados and floods combined. Its effects can be minimized, but not controlled.
“It” is expansive soil, better known in central Mississippi as Yazoo clay.
Expansive soil can shrink and swell by over 35%. The results can be dramatic. Patios, driveways and sidewalks may crack and bulge as the soil beneath them becomes wet and swells. Concrete slabs can crack and move sideways. Movement does not stop just because buildings get older. Many homeowners who have bought home warranties find that damage from expansive soil is not covered. In short, expansive soil is a big problem.
If you are buying a house and are concerned about Yazoo clay, there are several things you can do to discover its presence in an area.
First, ride around the neighborhood and notice whether the streets are smooth and flat or wavy. Streets in neighborhoods containing Yazoo clay tend to be wavy because of the expansion and contraction of the soil underneath the roadway.
Next, take a close look at the houses, especially around the window and door frames. If you see cracks, it is an indication that settlement of the foundation has occurred.
Third, talk to as many homeowners and real estate agents as possible about foundation conditions in the neighborhood.
Finally, talk to several — and I emphasize several — foundation repair companies about expansive soil. Ask them about its causes and ways to minimize its effects. There are techniques to minimize the problem. I hesitate to say that there are ways to cure the problem.
In theory, because moisture causes expansive soil to shrink and swell it is a good idea to keep the moisture level constant in clay soil. This means keeping it either wet or dry. Most experts will tell you that it is easier to keep it dry than wet, therefore they recommend things to keep water away from the foundation.
Some of the ways are:
• install gutters to remove water runoff from the roof;
• grade the soil so that water flows away from the house;
• install a French drain to move water around the foundation;
• control or remove trees next to the house; and
• water around trees in the dry season.
One foundation specialist told me that he had never seen a house with foundation problems that did not also have a drainage problem. One other thing that can cause problems is leaking underground water pipes that might be adding moisture to the soil under a house.
If you are building a new home, be sure that the builder performs a soil test and advises you of the soil condition upon which your new home is to be built.
I’m no expert, but I have had my share of dealings with Yazoo clay. I have owned three personal residences in Jackson. Every one of them has had some degree of damage from expansive soil. My first house was the worst. It seemed to shift or settle every time it rained. Doors would begin sticking, windows would not open and cracks would appear around window frames.
My wife and I were young and could not afford an expensive foundation repair. My neighbor came to the rescue. He took me under his house and showed me how he had installed several heavy duty jacks. He adjusted them as his house moved up and down. I’m sure that an engineer would not recommend such a course of action, but I did the same thing to my house and it worked. When the front door began sticking, I just adjusted a jack accordingly. I do not recommend this action; I’m just telling you what I did.
I learned later that an engineer or foundation specialist should do the job.
Our second house, a structure that was 50 years old, also had evidence of foundation settlement. I called every real estate agent I knew and asked for the name of the best foundation person in Jackson. One person’s name constantly came back. I called him and his repairs lasted a long time because he told me how to minimize the movement of the soil.
In our current home I combined what I had learned from the two previous houses, plus what research I had done on my on, and had a system installed that allowed for regular adjustment. Basically, it is a series of adjustable jacks on reinforced concrete piers. I figured that if I could not get rid of Yazoo clay I could at least roll with its punches.
Phil Hardwick’s column on Mississippi Business appears regularly in the Mississippi Business Journal. His e-mail address is firstname.lastname@example.org.