8 Signs of Foundation Problems
in North Texas Homes

The most common signs of foundation problems in North Texas homes are stair-step cracks in exterior brick, doors and windows that stick or won't latch, sloping or uneven floors, gaps where walls meet ceilings or cabinets, diagonal drywall cracks running from door and window corners, separation around exterior door and window frames, gaps under baseboards, and plumbing clues such as unexplained water bill spikes or damp spots on the slab. These happen because the DFW metroplex sits on expansive Blackland Prairie clay that swells when wet and shrinks during drought, moving the slab unevenly. Hairline cracks under about 1 mm and seasonal door sticking are usually cosmetic, while cracks past roughly 1/4 inch, floors approaching the ASCE Texas Section benchmarks of 1% tilt or 1/360 deflection, and any plumbing indicator warrant a professional elevation survey. Consistent foundation watering, correct grading, and extended downspouts are the cheapest preventive measures.

If you own a home anywhere from Fort Worth to Rockwall, you've probably heard a neighbor complain about their foundation. It isn't paranoia. North Texas sits on expansive clay soil that swells when it rains and shrinks when it doesn't, and our weather swings between both extremes, often in the same month.

That movement transfers straight into your slab. The trick is knowing which cracks and creaks are normal and which ones mean your foundation is actually moving.

Here are the eight signs worth paying attention to, and what each one usually indicates.

Why North Texas foundations move in the first place

Most of the DFW metroplex sits on the Blackland Prairie, roughly 12.6 million acres of clay soil running from the Red River southwest toward Bexar County (Texas Almanac). The signature soil here is the Houston Black series, Texas's official state soil and a textbook shrink-swell Vertisol. USDA soil survey data rates it as having very high shrink-swell potential and low strength, both listed as engineering limitations for building (USDA NRCS Ecological Site Description).

In practice that means a wet spring followed by a 100-degree August is a full expansion-and-contraction cycle, and your slab rides along with it.

A few common local factors accelerate the movement:

• Drought cycles that pull moisture out of the soil under the slab perimeter
• Large trees near the house drawing water from beneath the foundation
• Poor drainage or grading that dumps water on one side of the house but not the other
• Plumbing leaks under the slab, which saturate the soil in one spot and cause localized heave

The pattern matters more than any single crack. Foundation movement is almost always differential, one part of the house moves relative to another, and that's what produces the signs below.

1. Stair-step cracks in exterior brick or mortar

This is the classic one. Cracks that zigzag diagonally along mortar joints, following the brick pattern like a staircase, usually appear near corners, above windows, or where the brick meets a garage opening.

Why it happens: Brick veneer is rigid. When the slab beneath it drops or lifts unevenly, the veneer has to fail somewhere, and the mortar joints are the weakest path.

Cosmetic or serious? The most widely used framework for judging crack severity is the BRE / Burland damage classification, which sorts cracking by width (BRE, Assessing Cracks in Houses):

• Under ~0.1 mm (hairline): negligible
• Up to ~1 mm (about 1/32"): slight, normal redecoration handles it
• Up to ~5 mm (about 3/16"): moderate, fillable, may be visible outside
• 5 to 15 mm (roughly 3/16" to 5/8"): needs opening up and patching by a mason

So a hairline crack that hasn't changed in years is usually old movement that has stabilized. Once you're past about 1/4 inch, or the crack is wider at one end than the other, or the brick on one side sits proud of the other, get it looked at.

2. Doors and windows that stick or won't latch

You've probably been shouldering the back door for months and blaming humidity. Sometimes it is humidity. But if a door that used to close cleanly now catches at the top corner, or the deadbolt no longer lines up with the strike plate, the frame is out of square.

Cosmetic or serious? Seasonal sticking that reverses when the weather changes is usually wood movement. A door that has progressively gotten worse over two or three seasons, or several doors on the same side of the house misbehaving together, points to the frame being racked by foundation movement.

Quick test: Open the door halfway and let go. If it swings on its own, the frame is tilted.

3. Sloping or uneven floors

Walk the house barefoot. You'll feel a slope before you see it. Other tells: a marble that consistently rolls the same direction, furniture that rocks, or a noticeable dip in a hallway.

How much is too much? The ASCE Texas Section's Guidelines for the Evaluation and Repair of Residential Foundations, the reference most Texas engineers work from, uses two quantitative benchmarks: a deflection ratio of 1/360 and a tilt of 1% (ASCE Texas Section; full V2 guideline PDF).

To translate: 1% tilt is about 1 inch of fall every 8 feet 4 inches. Deflection of 1/360 over a 20-foot span works out to roughly 2/3 of an inch of bow.

Two important caveats. First, these are guidelines, not pass/fail thresholds; the ASCE document explicitly leaves room for engineering judgment. Second, without an original as-built elevation survey, nobody knows how flat your slab was on day one, so any measurement today is an approximation of how much it has moved (Post-Tensioning Institute, Evaluation Guidelines for the Performance of Slab-on-Ground Foundations).

If you can feel the slope walking across a room, it's worth measuring.

4. Gaps where the ceiling meets the wall, or where cabinets meet the wall

Look at your crown molding, especially in corners. A wedge-shaped gap opening at the top of a wall, or upper kitchen cabinets pulling away from the wall while the lower cabinets stay put, means the wall and the ceiling are moving at different rates.

Cosmetic or serious? This one rarely shows up from ordinary settling. Separation at the ceiling line usually indicates real vertical movement and deserves a look.

5. Drywall cracks radiating from door and window corners

Interior drywall cracks tend to start at the corners of openings, because that's where stress concentrates. A 45-degree crack running up and away from a door frame is the signature.

Cosmetic or serious? Fine, straight cracks along drywall seams and tape joints are extremely common and often just finish work aging. Diagonal cracks from opening corners, cracks that reappear within a year of being patched, or cracks wide enough to catch a fingernail are the ones to track.

Tip: Write the date next to a crack in pencil and note the width. If it has grown noticeably in six months, you have active movement rather than historical movement.

6. Separation around exterior window and door frames

From outside, look at where the brick meets your window frames, door frames, and garage door. Caulk joints that have pulled open, frames that appear tilted relative to the brick coursing, or a garage door that no longer seals evenly along the bottom all indicate the opening is no longer square.

Cosmetic or serious? Failed caulk on its own is just maintenance. Failed caulk plus a visibly out-of-square opening plus stair-step cracking nearby is a pattern, and patterns matter more than any single symptom.

7. Gaps under baseboards, or a visible gap along the slab edge

Look along the bottom of your interior walls. If the baseboard has separated from the floor in one area but sits tight elsewhere, the slab under that section has moved.

Outside, check the exposed edge of the slab where it meets the soil. On undisturbed Blackland Prairie ground, dry-summer surface fissures 2 to 4 inches wide and up to 2 feet deep are a documented normal characteristic of this soil, not a sign of failure.

Cosmetic or serious? Soil pulling away from the slab in August is expected here, and it's a signal to water your foundation, not necessarily to repair it. Baseboard separation on the inside is the stronger indicator and should be looked at.

8. Plumbing clues: unexplained water bills, damp spots, or slow drains

This one gets missed, and it's the one that most often turns a small problem into a large one. Foundation movement and plumbing problems feed each other. Movement can shear or crack sewer and supply lines running under the slab; a leaking line saturates the clay and causes localized heave.

Watch for:

• A water bill that jumps without a change in usage
• Warm spots on the floor (hot water line leak)
• A persistently damp area of slab or carpet
• Multiple drains slowing at once
• The sound of running water when nothing is on

Cosmetic or serious? None of these are cosmetic. A suspected under-slab leak should be tested promptly, both to stop the water loss and to keep it from destabilizing the soil under your foundation. Our slab leak testing can confirm whether a leak is active before structural damage begins.

Which signs mean.....
"call someone" and which means "keep an eye on it"

The single most useful thing you can do is track change over time. One crack tells you very little. The same crack measured in March and again in September tells you whether your foundation is stable or moving.

What you can do yourself right now

Several of the most common causes of foundation movement in North Texas are drainage and moisture problems you can address without a contractor:

• Water your foundation during dry spells. Run a soaker or drip line roughly 8 to 18 inches out from the slab edge, slowly and on a consistent schedule during hot months, and pause during wet spells. The goal is stable moisture, not saturation; overwatering one side can cause heave. Texas A&M AgriLife Extension also notes that drip and soaker systems use substantially less water than overhead sprinklers (AgriLife Extension, Irrigation of Lawns & Gardens).
• Fix your grading. The International Residential Code requires the ground to fall at least 6 inches within the first 10 feet away from the foundation, with impervious surfaces within 10 feet sloped at least 2% away (IRC R401.3).
• Extend your downspouts. Dumping roof runoff at the slab edge is one of the most common local causes of uneven moisture.
• Watch the trees. A useful rule of thumb: a tree closer to the house than its mature height is inside its zone of influence. For large shade trees on clay, that generally means 30 feet or more of separation. High-water-demand species, oak, willow, poplar, elm, account for most tree-related foundation problems.

When to get a professional evaluation

Get an inspection if you're seeing three or more of the signs above, if any single sign is clearly getting worse, if you're seeing any plumbing indicators, or if you're buying or selling the home.

A proper evaluation should include an elevation survey of the slab, actual measurements, not just a walkthrough, so you have a baseline to compare against later. If foundation movement is suspected, a static plumbing test is worth doing at the same time, since under-slab leaks are both a cause and a consequence of movement. See our DFW foundation repair cost guide for what an inspection and repair typically runs.

Quality Foundation & Plumbing evaluates both the foundation and the plumbing beneath it, so you find out whether you're dealing with soil movement, a leak, or both, before deciding on any repair.

Frequently Asked Questions