Concrete Crack Repair in Austin: How to Read a Crack Before You Fill It

About 1/32 of an inch. The ASCE Texas Section guidelines put the threshold plainly: injecting slab cracks of about 1/32 inch and larger with epoxy repair cement is intended to restore stiffness across the injected crack. The same paragraph says that if the only goal is to keep water or insects out, a sealant may be the right material instead, which is a much cheaper job. Around Austin, filling a minor crack runs $0.50 to $5 per linear foot, and a do-it-yourself crack repair kit is $15 to $100. So the question to put to a concrete company is not "can you fill it" but "are you restoring stiffness or sealing it", because those are two different products at two different prices.

When the crack comes with other signs that the slab has changed shape. On its own, a crack says very little: the Texas guidelines note that cracks may make concrete members weaker although the majority of cracks do not compromise structural integrity, and that the physical characteristics of the crack are what matter. The list those engineers use for inadequate foundation performance is longer than the crack itself. It includes cracking or separating of exterior walls, rotating or buckling masonry veneer, separating of walls from ceilings or floors, racking of door and window frames, cracking or buckling of floor coverings, and separating of joints that were originally tight. The guidelines add a caution worth repeating: seeing some of those conditions does not by itself mean the foundation is performing badly, and the age of the house and any earlier repairs change how much each sign means.

There is also a number. Where a floor profile shows deflection smaller than the L/360 limit borrowed from the residential code, the guidelines say it is unlikely the foundation is deflected materially unless visible indications show otherwise.

It changes volume with the weather, and it does it hard. Houston Black clay, the soil series whose type location is in Travis County, opens cracks 0.5 to 4 inches wide when it dries, extending 12 inches or more down, and those cracks stay open 90 to 150 cumulative days in most years. The Texas guidelines describe the mechanism in one line: Texas has large areas with clayey soils that shrink and swell with changes in soil moisture content, and that shrinking and swelling may cause movement of residential foundations. Austin's habit of swinging from drought to flash flood drives the same cycle, which is why local slabs sink and fissure.

Trees are part of this. The guidelines warn that trees or large shrubs near a foundation may cause soil shrinkage under it, that removing them may stop the shrinkage or partly restore areas that dropped, and that removal can instead cause upheaval as soil moisture comes back, especially when the tree was there before the house. They recommend a waiting period after removal to let the soil heave. Around Austin, roots hunting moisture in dry spells buckle driveways too, and they have to come out before new concrete goes in. The driveway page covers how the base under a new pour is built for this.

A licensed professional engineer. The Texas Board of Professional Engineers and Land Surveyors describes engineering as a service whose adequate performance requires engineering education, training and experience in applying special knowledge or judgment of the mathematical, physical or engineering sciences. The guidelines used across Texas to judge residential foundations say they are primarily suited as an aid for engineers, and that an engineer doing an evaluation should personally visit the site and be in responsible charge of the investigation. Those guidelines describe three levels of work: a Level A report of first impressions, a Level B report that adds measured relative floor elevations and reports deflection and tilt against acceptable tolerances, and a Level C investigation that can add soil sampling, plumbing tests, a steel reinforcing survey and post-tensioning cable testing.

In Kyle this is already written into the permit: foundation repair needs a permit, and because of the expansive soils the city wants an engineered design and a sealed engineer letter at inspection. Austin Trusted Concrete is a referral service. We do not inspect slabs, measure floors, diagnose movement or decide what your crack means. If you want a crack priced, our vetted local concrete pro can come out and quote the work; if you want to know whether the foundation has moved, that is a separate appointment with an engineer. How we vet our pros lists the checks we make first.

It can help, and Austin's rules decide how. The Texas foundation guidelines tell engineers to inform the client that keeping soil moisture close to uniform on all sides of the foundation may be beneficial, while cautioning against excessive watering. Austin has been under Conservation Stage water use restrictions since September 2, 2025, and the schedule is specific:

• Hose-end sprinklers and drip irrigation: 2 days a week, midnight to 10 a.m. or 7 p.m. to midnight. Even addresses Thursday and Sunday, odd addresses Wednesday and Saturday.
• Automatic and manual irrigation systems: 1 day a week, same hours. Even addresses Thursday, odd addresses Wednesday.

The exemptions are the useful part here. Austin Water allows watering with a hand-held hose or a refillable container at any time on any day, and watering trees with a soaker hose, a Treegator or an automatic tree bubbler at any time on any day. A soaker hose along the slab edge is not on a watering day, in other words. Check your own address and your HOA before you set anything up, and if the soil is already moving, ask the engineer what watering pattern they want rather than guessing.

Not on your own lot. Austin says sidewalks and driveways that are not in the public right-of-way need no building permit and no Driveway/Sidewalk permit, though the work still has to meet the residential code. The part of the driveway at the street is different: repairing a driveway approach, sidewalk, curb or gutter in the right-of-way is Driveway/Sidewalk work, and a right-of-way contractor's license is required to perform it. The permit guide has the fee table, and price updates logs every range on this site with the date it changed.