Foundation crack repair in Houston

Foundation crack repair in Houston depends on what caused the crack. A narrow, stable crack in a slab can be sealed with an epoxy or polyurethane injection, which national figures put at about $250 to $800. A crack that keeps widening, runs horizontally, or comes with sticking doors and sloping floors usually means the slab is moving, and the fix is piers under the house to stop that movement. This page covers which cracks matter, how each kind gets repaired, what it costs here, and when to get a contractor out to look.

How does a cracked foundation get fixed?

A cracked foundation gets fixed in one of two ways. If the crack is narrow and has stopped moving, a contractor seals it with an injected epoxy or polyurethane, which blocks moisture and restores the surface. If the ground under the house is still shifting, sealing alone fails, so the contractor installs piers to support the slab, lifts it toward level, and then seals the cracks that remain.

Injection does nothing about the pressure that opened the crack, so on Houston clay a crack sealed over active settlement often reopens.

A typical visit:

1. Look and measure. Crack width, any offset, sloping floors and sticking doors.
2. Find the cause. Poor drainage, a plumbing leak under the slab, tree roots and dry soil are the usual suspects here.
3. Choose the repair. Sealing for a stable crack, piers for a moving foundation, and drainage work when water is the trigger.
4. Price it in writing before any work starts.

In the City of Houston, foundation repair needs a building permit, and the weekly city permit reports list them by the dozen. For a step-by-step view of the work itself, see how a cracked foundation is repaired.

How big is too big for a foundation crack?

A crack wider than about 1/4 inch is one of the signs that it may be structural, according to This Old House. Width is only part of the story, though. A crack that keeps growing, has one edge sitting higher than the other, or appears alongside sloping floors or sticking doors matters more than a wider crack that has stayed the same for years.

Very fine hairline cracks are common in concrete slabs as they cure and dry. They are usually cosmetic.

To tell whether a crack is active, pencil a mark and the date at each end and photograph it beside a ruler. If it grows past the marks within a few weeks, it is moving. Our guide on when foundation cracks are worth worrying about goes through the warning signs in more detail.

What are the different types of foundation cracks?

Foundation cracks fall into a few patterns. Vertical cracks are often linked to normal shrinkage and settling. Diagonal cracks usually form when one part of the foundation settles more than another. Horizontal cracks are the most concerning, because they point to pressure pushing on the foundation from outside. In brick veneer, a stair-step crack along the mortar joints usually means the slab beneath that wall has moved.

How each shows up in a Houston home:

• Hairline cracks in the slab surface, often under flooring or in the garage. Mostly shrinkage from when the concrete cured.
• Vertical cracks in the slab edge or grade beam. Often stable, but worth sealing to keep moisture out.
• Diagonal cracks running from the corners of doors and windows, inside or out.
• Stair-step cracks in exterior brick. A common sign of a dropped corner. See stair-step cracks in brick walls.
• Horizontal cracks. Most common in retaining or below-grade walls elsewhere in the country. Houston homes rarely have a basement, so here they turn up mostly in block or brick walls under pressure.

The differences between the two main directions are covered in vertical vs horizontal foundation cracks, and pictures of normal foundation cracks shows what usually needs no repair.

How much does foundation crack repair cost in Houston?

Sealing a single crack typically costs about $250 to $800, based on a national 2026 cost guide. If the crack is a symptom of settlement and the slab needs piers, the job moves into the range most Houston foundation repairs fall in, about $3,300 to $6,800. The number of piers, interior access and how far the slab has dropped drive the final price.

These are guides, not quotes. The contractor prices your house after seeing it. The same national guide notes that a hairline crack sealed for a few hundred dollars can grow into a $10,000 to $15,000 repair if the movement behind it is left alone. There's a full breakdown on the foundation crack repair cost page.

Can Flex Seal or a DIY kit fix foundation cracks?

Flex Seal and similar spray coatings can cover a hairline crack on the outside of a slab and slow moisture getting in, but they are surface coatings. They do not bond the concrete back together or stop the slab from moving. A DIY injection kit does a better job on a narrow, dry, stable crack. Neither fixes a crack caused by settlement or soil pressure.

DIY is reasonable when the crack is narrow, your pencil marks show it has stopped growing, and floors and doors are fine.

Hydraulic cement fills visible cracks in masonry or concrete block, but it is usually cosmetic, according to This Old House. The trade-offs between the main fillers are in hydraulic cement for foundation cracks and epoxy injection for foundation cracks.

Call a professional when the crack is wider than about 1/4 inch, one side is offset, it keeps coming back, or the house shows other signs of movement.

What happens if you don't fix a cracked foundation?

A stable hairline crack left alone usually stays cosmetic. A crack caused by movement tends to get worse: it widens, lets moisture reach the steel inside the slab, and spreads into drywall, brick and door frames. The longer the slab keeps moving, the more piers it may need, and the more interior finishes need repairing once it's leveled.

Water is the main risk: moisture getting under flooring or into a wall cavity can cost more to put right than the crack itself.

Why do foundations crack so often in Houston?

Most Houston foundations crack because of the soil they sit on. Much of the area is heavy clay that swells when wet and shrinks when dry. The USDA describes Lake Charles clay, found across southeast Texas, as 45 to 60% clay, cracking 1/2 to 2 inches wide at the surface in dry spells. That constant swelling and shrinking puts uneven pressure on a slab.

Three local factors add to it:

• Moisture swings. Long dry summers followed by heavy rain move the soil under the edges of a slab more than the middle.
• Subsidence. The Harris-Galveston Subsidence District measured the fastest sinking, over 3 cm a year, around Katy and Fulshear. Homes in Katy see foundation movement for this reason as well as from clay.
• Older pier-and-beam houses. In neighborhoods like Houston Heights, many older homes sit on piers rather than a slab, and cracks show up in plaster and siding rather than concrete. Lake Charles clay was first described in Fort Bend County, so Sugar Land homes sit on the same heavy soil.