Foundation problem guide

Cracks in Your Foundation, Walls, or Slab?

Not every crack is structural. Answer a few questions and Fixly Guide will help you tell cosmetic cracking from movement worth an engineer’s time.

Get an Evaluation Quickly If You See This

Treat it as urgent if you see:

  • Horizontal cracks or a wall that is bowing inward
  • Cracks wider than about a quarter inch, or widening month to month
  • Doors and windows that suddenly will not latch
  • Separation between walls and ceilings, or a visibly sloping floor
  • Cracks paired with a water leak or a spiking water bill

Bowing walls, horizontal cracking, or sudden separation at ceilings and door frames can indicate active structural movement. Keep people out of the affected area and get a structural engineer out before any repair company writes a scope.

Quick answer

Width, direction, and change over time tell you most of it. Thin vertical hairlines in newer concrete are usually shrinkage. Horizontal cracks, bowing, stair-step cracking wider than a quarter inch, and cracks that grow month to month point at movement. Mark and date every crack now so you have evidence, then rule out drainage and under-slab leaks before agreeing to piers. This page is educational information, not a structural assessment of your home.

Possible causes

Normal concrete shrinkage

Hairline cracks in the first year or two are typically curing shrinkage, not movement.

Soil moisture swings

North Texas clay expands and contracts dramatically between wet and dry seasons, lifting and dropping slabs.

Poor drainage at the perimeter

Downspouts dumping at the foundation soak one side while the other dries out.

Plumbing leaks under the slab

A slow under-slab leak saturates soil in one spot and causes localized heave.

Large trees near the structure

Root systems pull moisture out of clay and shrink the soil beneath a corner.

Original construction or fill issues

Improperly compacted fill settles unevenly for years after the build.

Retaining or basement wall pressure

Horizontal cracking and bowing indicate lateral soil pressure, which is a structural issue.

How this project is usually classified

General guidance for this problem type — not a diagnosis of your home.

Typical urgency
Soon — within weeks
Safety risk
High safety risk
DIY suitability
Licensed pro only
Cost level
Major investment
Repair option
Drainage correction and targeted pier installation where movement is measured.
Replacement option
Full underpinning when settlement is widespread.
Typical timeline
Engineer report first; work typically several days
Contractor type
foundation

What you can safely check yourself

  • Photograph each crack with a coin or ruler for scale and date the photo.
  • Mark the ends of a crack with a pencil line so you can see if it grows.
  • Walk the perimeter and check that downspouts discharge several feet from the house.
  • Check the water meter with everything off to rule out an under-slab leak.
  • Note whether doors and windows stick in only one part of the home.

Before the pro arrives

  • Have your dated crack photos and measurements in one place.
  • Know the home’s age and foundation type — slab, pier and beam, or basement.
  • Note any recent plumbing work, drainage changes, or tree removal.
  • Ask whether an independent structural engineer report is warranted first.

Questions to ask

  • Is this cosmetic cracking or evidence of movement, and how do you know?
  • Do you recommend an independent engineer’s report before any repair?
  • What is causing the movement — drainage, plumbing, or soil?
  • What does the repair warranty cover, and is it transferable?
  • What happens if the foundation keeps moving after the work?

Common questions

Which foundation cracks are serious?

Horizontal cracks, bowing walls, stair-step cracks wider than about a quarter inch, and any crack that keeps widening are the ones that warrant a structural evaluation. Fine vertical hairlines in newer concrete are usually shrinkage.

Should I hire an engineer or a foundation repair company first?

An independent structural engineer has no financial interest in selling piers. For anything beyond obvious cosmetic cracking, an engineer report first gives you a neutral scope to bid against.

Why do foundations move so much in Texas?

Expansive clay soil swells when wet and shrinks when dry. That seasonal cycle lifts and drops parts of a slab, which is why consistent perimeter moisture and good drainage matter so much here.

Can a plumbing leak cause foundation cracks?

Yes. A slow under-slab leak saturates soil in one area and causes localized heave. A sudden jump in your water bill alongside new cracking is worth a leak test before any pier work.

Keep reading

Other common home problems

Start with the symptom and get likely causes, safety guidance, and a next step.

See all problem guides

Fixly Guide provides educational guidance only. Nothing here is a professional diagnosis, an inspection, or a guarantee of contractor availability or pricing.