Foundation Types in Tennessee, Mississippi, and Arkansas

A single concrete slab poured directly on prepared soil, usually with a thickened perimeter beam. Standard in this region from roughly the mid-1960s onward.

Slabs typically fail at the perimeter first, because the edge soil dries and wets faster than soil under the middle of the house. Repair means restoring support under the footing, usually with driven piers, and correcting the moisture condition that caused the loss.

A wood floor system carried by girders that rest on masonry or concrete piers, with a crawl space beneath. Standard in pre-war and early post-war construction and still used on some rural sites.

Failure shows up as sloping and bouncy floors from settled piers, decayed sills and joist ends, or undersized girders. Repair rebuilds the support system and addresses the crawl space moisture that caused the decay.

A variation on pier and beam where a continuous masonry perimeter wall carries the exterior load and interior piers carry the middle of the house.

These fail at both the perimeter wall and the interior piers, and they concentrate moisture problems because the enclosed space has limited air movement.

Less common here than in the Midwest but present, especially on the sloped terrain around Oxford and parts of north Mississippi and eastern Shelby County.

The dominant failure mode is lateral: saturated soil pushes against the wall until it bows or cracks horizontally. Repair combines structural restraint — carbon fiber, steel bracing, or anchors — with drainage that reduces the pressure.

Many houses are more than one type. An original crawl space home with a slab addition, or a slab house with a crawl space under a later den, has two support systems that move independently. The joint between them is where the cracking shows up.