SOUTHLAKE

Southlake is mostly a product of the nineties onward, and the houses are large. That matters more than it sounds: a big footprint spans more ground, and the more ground a slab covers the more likely it is to bridge a change in soil.

On Cross Timbers land, where sandy surface soils sit over clay and the depth to clay varies across a single lot, a wide house can have quite different support under one end than the other. Most of this land was pasture within living memory and had to be graded before anyone built on it.

What the ground under Southlake is actually doing

Southlake is the sandiest place we work. Gasil covers over 17% of it at a linear extensibility of 1.2, with Rader at 2.5 and Crosstell at 4.9. Nothing here is a serious expansive clay.

Which makes Southlake’s large houses the real variable rather than its soil. A wide footprint spans more ground, and on Cross Timbers land the depth from sand down to clay changes across a single lot. The bigger the slab, the more likely it is to bridge that change — and a slab bridging a soil boundary will move even when neither soil is especially active.