Slab-on-grade foundations consist of a thick layer of reinforced concrete that rests directly on top of the soil. These types of foundations are usually used in warmer climates where the ground does not regularly freeze. These foundations are relatively inexpensive to install, sturdy, and do not have the potential for mold, insects, and radiant heat loss as crawlspace foundations.
Slab-on-grade foundations are typically supported by a rebar framing and steel wire mesh to provide a small measure of flexibility as the home settles. However, even if the ground does not regularly freeze, it is still susceptible to expansive soil damage without proper mitigation techniques.