Foundation crack repair

Which cracks matter

Wide, horizontal, tapered, offset or growing cracks matter (HUD, 2000); a hairline crack that isn't changing usually doesn't (HUD, 1997). What each pattern usually means:

Why foundations crack

Concrete shrinks as it dries, and the soil under it moves. HUD's rehab guide lists settlement, expansive soils and water pressure from high water tables among the causes of cracks in basement walls and floors (HUD, 1997).

Clay under a slab

Texas has large areas of clay that shrinks and swells as its moisture changes, which can move a house's foundation (ASCE Texas, 2022). USDA's soil survey rates land for that risk, and its rating text for houses without basements says excessive shrink-swell "can cause building foundations to shift, flooring slabs to crack and roadways to buckle" (USDA NRCS, 2018). The clay shrinks as it dries (Colorado Geological Survey), and trees or large shrubs near a house can shrink the soil under its foundation (ASCE Texas, 2022). Texas engineers suggest keeping the moisture even on every side of a slab (ASCE Texas, 2022); foundation watering covers how, and which clay counties are in drought this week.

Water against a basement wall

Saturated soil presses on a basement wall harder the deeper it goes, and the weight of the wet soil adds to the load (FEMA P-312, 2025). Freezing adds to it: saturated soil that swells or freezes and heaves against a block or brick wall is one cause of horizontal cracks (HUD, 2000). FEMA notes that some older homes were built with unreinforced basement walls, which can buckle or collapse (FEMA, 2025).

Settling

Settlement most often comes early in a house's life or after a big change underground (HUD, 2000). The rehab guide's list of poor soils includes highly expansive soils, organic or silty soils, and fill that wasn't compacted in layers; water can also carry fine soil out from under a foundation or loosen soil until it settles (HUD, 1997).

Where clay and shallow water tables are common

Clay is the more common limit in Texas cities, and a shallow water table in Ohio's. Shrink-swell clay limits houses without basements on more than half the mapped land in 525 of the 1,227 Texas cities and 55 of the 922 Ohio cities. A shallow water table limits basements on more than half the land in 136 Texas cities and 573 Ohio cities.

We measured both inside city limits: USDA's soil survey clipped to the Census boundary of every incorporated city in the two states, with homes from the Census Bureau's American Community Survey. Each group's homes are also shown as a share of all homes in the state's cities.

How each kind of crack is repaired

Sealants and injections close a crack, anchors hold a bowed wall, and piers carry a settling footing; which one fits depends on what moved. HUD's rehab guide says not to start on any of them until the cause is known (HUD, 1997).

• When a slab crack only needs to keep out moisture or insects, Texas engineering guidelines say a sealant may be appropriate (ASCE Texas, 2022). A surface patch of grout reaches only 1 to 2 inches into a crack, even one chipped open first, and is more cosmetic than structural (HUD, 1997).
• Epoxy injected through ports drilled along a crack in poured concrete can restore its structural soundness, once the foundation is stable and the crack has stopped growing (HUD, 1997). It can't go into a crack that is leaking water, works better in poured walls than in block, and won't stop new cracks beside the repair if the soil keeps moving (HUD, 1997). Texas guidelines use it on slab cracks about 1/32 inch and wider (ASCE Texas, 2022).
• Polyurethane (urethane) injection is used to stop a crack that leaks. It expands into a closed-cell foam that water can't pass and stays flexible enough for cracks with a little movement, up to 1/8 inch with some grouts, but it adds no structural strength (HUD, 1997). The guide advises against it in block walls, where the expanding foam can crack the block (HUD, 1997).
• A basement wall bowed inward can be held, and sometimes straightened, with anchors: a plate set in a pit in the soil outside, or a helical anchor screwed into the soil, tied through the wall to a plate on its inside face (HUD, 1997). An earth anchor can't bring the wall fully back to vertical; only removing the soil outside could (HUD, 1997). HUD's inspection guide also describes jacking a wall back into place, reinforcing it with interior buttresses or epoxy grout, and lowering the ground outside to take off some of the pressure (HUD, 2000).
• A settling foundation can be strengthened with new pilasters or injected epoxy grout, and if the movement continues and the cracking is extensive, underpinning may be the only fix (HUD, 2000). The piers used include steel mini-piers driven hydraulically to rock or firm soil, usually 15 to 25 feet down (HUD, 1997), and helical piers screwed into stable soil; either can hold a footing or lift it (HUD, 1997).

Texas engineering guidelines add that underpinning doesn't improve the parts of a foundation left without it, and that lifting a foundation on piers, which can raise it clear of swelling clay, is unlikely to leave it level (ASCE Texas, 2022). They also say it may be prudent to try non-structural steps and watch the foundation before, or instead of, structural repair: a watering program, gutters and downspouts, drainage, root barriers (ASCE Texas, 2022).

What crack repair costs

Of the 10 US figures below, 4 put a crack repair at $250 to $800 (Angi, HomeAdvisor, HomeGuide and Bob Vila). The highest is Thumbtack's $1,982 to $7,290 per job, and HomeGuide prices minor structural work at $1,000 to $5,000. Piers used for underpinning are priced per pier in the second table; whole-job prices are in the foundation repair cost guide.

When to get an engineer's evaluation

Get one when a crack is horizontal, tapers, has sides out of line, is 1/8 inch or wider, or keeps growing. HUD's inspection guide advises a structural engineer for masonry problems, and a soils engineer as well when differential settlement looks like the cause (HUD, 2000). Settlement is usually slow, which leaves time to research the cause before any repair (HUD, 1997).

In Texas, the engineering guidelines call for a professional engineer licensed in the state to do the evaluation and design the repair (ASCE Texas, 2022). What an evaluation involves and what it costs: foundation inspection cost.