Every year in late June we have a version of the same conversation, usually three or four times in a single week. A homeowner calls and says some combination of: the front door is sticking, there's a new crack in the drywall above the bedroom doorway, the garage floor has a line that wasn't there last summer.
And every year we have to say the same thing back. "Yeah. Welcome to Texas in July. Let's talk about what's actually happening under your house, because the news isn't terrible — but the next ninety days matter."
If you live in DFW and your home sits on a concrete slab — which is the vast majority of homes built here in the last forty years — your foundation is moving right now. Not catastrophically. Probably not even visibly yet. But the soil under your slab is shrinking, and the question isn't whether your foundation is shifting this summer, it's how much and what you're doing about it.
This is the foundation conversation we wish every Fort Worth homeowner would have with themselves once a year. The good news is, the most important thing you can do about it costs almost nothing and takes about twenty minutes a day.
What Is Actually Happening Under Your House
The soil across most of DFW — Trinity Clay, Eagle Ford Clay, Houston Black Clay, the "black gumbo" stuff that turns rock-hard in August and sticky in March — is what geologists politely call "expansive." Less politely: it's the worst soil in the country to build a house on, and we built a metro of eight million people on top of it anyway.
When this clay is wet, it expands. When it dries out, it shrinks. The technical numbers are wild — Trinity Clay has a plasticity index of 51.9, which is about as high as residential soil shrink-swell gets. Eagle Ford can move vertically as much as seven inches across a single dry-to-wet cycle. Seven inches. Under a slab that was poured to be perfectly flat.
In a wet spring like the one we just had, the soil is plump with moisture and your slab is sitting evenly on it. Then July arrives, the rain stops, the temperature pegs to 100 for two weeks, and the clay under your house begins to dry. It shrinks. It pulls away from the perimeter of your slab. Gaps form. Voids open up.
If the soil dried out perfectly evenly across your entire lot, your house would just settle down a quarter inch and you'd never know. But it doesn't. The shade under the big oak tree dries differently from the sunny side of the yard. The flowerbed by the front porch dries differently from the strip of grass next to the driveway. The area where your downspout dumps water dries differently from the corner that gets no runoff at all.
That uneven drying is what cracks foundations. The slab doesn't sink — it twists. One corner drops a half inch while another corner holds steady, and somewhere in the middle of the house, a doorframe stops being a rectangle.
The Warning Signs You Should Be Walking Around Looking For Right Now
Take twenty minutes this weekend and walk your house. Inside and out. Here's the checklist.
Doors. Every interior door. Open and close each one. Does any of them stick? Catch at the top? Refuse to latch where they latched in March? A door that no longer fits its frame is one of the earliest and most reliable signs of slab movement.
Drywall corners around door and window openings. Look up at the top corners of every doorway and window inside the house. Are there cracks angling diagonally up and out from the corner? Stair-step cracks running along the seams? Most homes have a few hairline cosmetic cracks from normal settling. The ones to flag are wider than the edge of a credit card, growing visibly over weeks, or running through trim and not just paint.
The brick or stone exterior. Walk around the outside. Look for stair-step cracks in the mortar — the diagonal zigzags that follow the brick joints. Look at the gap between the trim around your windows and doors and the masonry. Gaps that weren't there before are a real sign.
Floors. Take a level into a few rooms. Or just put a marble on the kitchen floor. If it rolls noticeably and consistently in one direction, that's not "an old house." That's slab movement.
Around the perimeter of your slab. Walk the outside of your house and look at the dirt right against the foundation. Is there a visible gap between the soil and the concrete? That gap is the soil pulling away. The soil should be in contact with the concrete. When it isn't, you have an open invitation for water — when it does eventually rain — to run straight down against the foundation and do its own damage.
A few of these signs together, especially if they're getting worse over a few weeks, is the moment to call a foundation engineer for an honest assessment. Not a "free inspection" from a foundation repair company — those are sales calls. A licensed structural or geotechnical engineer charges a few hundred dollars for an independent opinion and is worth every penny.
The Twenty Minutes a Day That Saves You Twelve Thousand Dollars
Here's the part most homeowners haven't been told plainly enough.
The single best thing you can do for your DFW slab foundation in July, August, and September is water it. On purpose. Methodically. Every day.
The technique is simple. Lay a soaker hose around the perimeter of your house, about 12 to 18 inches out from the foundation — not against it. Bury it just under the surface or cover it with mulch. Run it for somewhere between 15 and 30 minutes in the early morning, five days a week through the worst of the heat. The goal isn't to flood the yard. The goal is to keep the soil along the perimeter consistently damp — not muddy, not bone dry — at a depth of six to eight inches.
Quick check on whether you're watering enough: take a long screwdriver and push it into the dirt six inches off the foundation. If it slides in to the handle without resistance, you're good. If it stops dead after an inch and a half, the soil is too dry and you need more water, more often.
A few practical notes for Fort Worth and Dallas residents. Both cities have moved to permanent twice-a-week outdoor watering restrictions: odd-numbered addresses water Wednesday and Saturday, even-numbered addresses water Thursday and Sunday, and irrigation is prohibited from 10 a.m. to 6 p.m. between April and October. Foundation watering falls under irrigation. So your soaker hose schedule has to fit those days and those hours — early morning is the smart choice anyway, because evaporation in afternoon Texas summer is brutal.
