The entire DFW area has expansive clay soils. The poor soils are the biggest factor in causing foundation problems. Some areas are worse than others, but clay soils are located throughout the metroplex. Carrollton (Denton County) has the most expansive soil in the country.
Age of Home
The older the foundation, the less it was engineered. A big factor for foundation strength is the size and frequency of beams. Newer slabs will have larger and more frequent beams while older slabs will have smaller and less frequent beams. The less rigid the slab, the more likely it is to have foundation problems.
Most homesites will have some degree of fill dirt. Most lots that homes are built on are not level and need to be graded. The high areas are cut down and the low areas are built up (fill dirt). If the slope of the lot is sufficient enough, it will require retaining walls to hold the fill dirt. The fill dirt areas are typically not compacted as well as Mother Nature does. That un-compacted fill dirt can compress over time leading to settlement.
Poor drainage will affect foundation performance. Many older homes are built in flat areas and drainage is a problem.
Improper maintenance increases the likelihood of foundation problems. You guys have seen this when you’ve purchased a property (without a foundation problem), then develop a problem while rehabbing the house during the summer months while it maintaining the moisture content of the soil (watering).
Sometimes luck is a factor. Our analysts have seen homes where one owner meticulously maintains his home and ends up with a foundation problem and his neighbor neglects his home and doesn’t have a foundation problem. Both homes are sitting on the same soil and were built by the same builder with the same construction techniques.
Overall, there is no part of the metroplex that is completely devoid of foundation problems. However, there are some areas where essentially all homes have or have had foundation problems