Foundation Inspection Alamo Heights, TX.

The older blocks of Alamo Heights, especially those backing up to the Olmos Basin drainage corridor, sit on high-plasticity Houston Black clay, soil that swells through wet springs and pulls back hard in the summer drought. Many of the homes here are mid-century masonry on shallow perimeter beams, poured before anyone fully appreciated how much that Blackland Prairie clay would shift underneath them.

An inspection is where you stop guessing. Surface clues like a sticking door or a hairline crack are lagging signs, by the time you notice them, the slab has already moved. What we measure on site is the actual elevation of the foundation at every accessible point, so the conversation starts with data instead of a hunch.

What happens during the visit

What the elevation survey actually tells us

A contour of the slab separates two things that look identical from the curb: movement that is still active and movement that stabilized years ago. A corner sitting three-quarters of an inch low relative to the interior is a different problem than a center reading higher than the perimeter, which usually points to heave rather than settlement. The gradient between points tells us whether the structure is tilting toward a low-drainage zone, a common pattern on lots that slope toward the basin.

That distinction drives the whole recommendation. Plenty of Alamo Heights homes show old, finished movement that needs watching, not piers. The survey is what lets us tell you that honestly, because the numbers don't care which answer is more profitable.

Depth is the other thing the report addresses. The active zone, the layer where seasonal moisture swings actually move the clay. Typically runs 10 to 15 feet down in this part of Bexar County, where plasticity indices commonly land between 40 and 60. Any support that stops inside that zone keeps riding the seasons. GroundLock's galvanized steel piers are driven hydraulically to refusal on stable load-bearing strata below it, often 10 to 25-plus feet down depending on the lot.

What the inspector checks beyond the numbers

The elevation map is the core of the report, but a thorough visit also documents the conditions feeding the movement:

• Perimeter grade, whether the soil drops at least 6 inches over the first 10 feet, or whether it traps rainwater against the beam
• Downspout and gutter discharge, where roof runoff lands, and how close it is to the foundation
• Irrigation and soaker-hose placement, lines too close to the beam can heave one corner while the rest of the slab stays dry
• Tree roots and leaking lines, localized drying that explains why movement so often concentrates at a single corner
• Interior and exterior symptoms, stair-step brick cracks, drywall fans from door corners, gaps at trim and ceiling, slab and garage-floor cracks
• Crawl or beam access, how much working room exists around the slab, which affects scope and cost

Alamo Heights inspection questions, answered