Root barriers
Stopping a big tree drinking the water out from under your slab
College Hills is one of San Angelo's established residential areas, and one of the names that comes up most often when people talk about where to live in town.
College Hills has been a settled, desirable part of San Angelo for a long time, and neighborhoods like that share a feature that turns out to matter a great deal for foundations: mature trees. A street lined with big canopy trees is exactly what makes an established neighborhood pleasant to live in, and on shrink-swell clay it is also a live factor in what the ground under the houses is doing.
Trees and clay foundations compete for the same water. A mature tree draws moisture out of the soil across its whole root spread, and on clay, removing water means the ground contracts. When that happens on one side of a house and not the other, the foundation tilts toward the tree. The pattern is distinctive and it is what separates tree-driven movement from ordinary settlement: it gets measurably worse through the dry months and eases off after a wet stretch, year after year, rather than progressing steadily in one direction.
The instinct when a tree is implicated is to remove it, and that is frequently the wrong call. A large tree is often the best thing on the lot, and taking one out abruptly lets the soil it was keeping dry rehydrate and swell — movement in the opposite direction, which can crack a house just as effectively. A root barrier is usually the better answer: a vertical barrier set between the tree and the house that redirects root growth downward, leaving the tree standing.
The way to settle any of this is measurement rather than opinion. A free evaluation takes relative floor elevations across the house, records where and how the cracking runs, and looks at what the drainage and any nearby trees are doing to the soil — and you get that in writing. Quite often the answer is that the movement is old, stable and needs nothing, which is a perfectly good outcome and costs you nothing to establish.
Where work is needed, the plan should name every pier and its location before anything begins. Texas issues no foundation repair license, so a written scope, insurance confirmed with the insurer, an engineer's involvement, and a warranty in writing are the four things worth asking of anyone. How to judge a foundation contractor in Texas →
Ground and climate facts on this page come from the USDA Natural Resources Conservation Service Official Soil Series Descriptions for the Tobosa, Lipan and Angelo series (all three mapped in Tom Green County) and from NOAA climate normals for San Angelo.
Stopping a big tree drinking the water out from under your slab
Piers driven under a settling slab until it carries the house again
Measured floor elevations and a written report before anyone sells you piers
Measured, written down, and no obligation either way.