Katy Guide

Foundation Cracks: Which Ones to Worry About

A plain guide to the cracks Katy-area homeowners see most, what they usually mean, and when it's worth calling a foundation pro.

Last updated October 2026

Quick answer

Most small cracks, like hairline drywall cracks or thin vertical cracks in concrete, come from shrinkage or minor movement and can be monitored. Crack width alone isn't a pass/fail test: engineers look at the pattern, any offset, whether the crack is growing, and floor levels. Cracks that are growing, offset, around 1/4 inch wide, or showing up with sticking doors or sloping floors are worth having looked at. Sources: InspectAPedia damage guide; ASCE Texas Section guidelines (2022, PDF).

Chart titled "Is this crack serious?" sorting common crack types into three levels. Usually normal, watch it: hairline cracks in drywall; small vertical slab crack. Worth a closer look: stair-step cracks in brick; diagonal cracks at door or window corners; sticking doors or new gaps at trim. Call a pro: offset slab crack, or wider than about 1/4 inch.
Chart: Katy Guide. General information, not an engineering assessment.

Common crack types

  • Hairline cracks in drywall

    Looks like
    A thin crack in drywall, thinner than 1/16 inch.
    Usually means
    Usually shrinkage or minor movement.
    Monitor or call?
    Monitor it.

    Sources: InspectAPedia damage guide; InspectAPedia crack dictionary.

  • Small vertical slab crack

    Looks like
    A thin crack in the concrete slab, 1/8 inch or narrower, with both sides level.
    Usually means
    Hairline vertical cracks in concrete are usually shrinkage. ASCE Texas Section guidance says slab cracks 1/8 inch or narrower don't typically mean the slab can't perform as intended, and that cracks in slab-on-ground foundations don't indicate a life-threatening condition.
    Monitor or call?
    Monitor it.

    Sources: InspectAPedia damage guide; ASCE Texas Section guidelines (2022, PDF); TexasInspector buyer's guide (PDF).

  • Stair-step cracks in brick

    Looks like
    A crack that steps up or down along the mortar joints in brick.
    Usually means
    A typical sign of differential settlement, where one part of the house moved more than the part next to it.
    Monitor or call?
    Get an inspection if the crack is new, growing, wider than 1/4 inch, or offset.

    Sources: InspectAPedia crack dictionary.

  • Diagonal cracks at door or window corners

    Looks like
    A crack running diagonally from the corner of a door or window.
    Usually means
    Openings concentrate stress, so one hairline crack at a single corner is common. The same diagonal crack at several openings, especially with doors that no longer latch, points to movement underneath. InspectAPedia lists expansive clay soil and trees near the foundation among the causes.
    Monitor or call?
    Get it looked at when the same diagonal crack shows up at several openings, or with doors that no longer latch.

    Sources: InspectAPedia crack dictionary.

  • Sticking doors or new gaps at trim

    Looks like
    Doors or windows that stick or no longer latch, or new gaps between trim or baseboards and the wall or floor.
    Usually means
    Signs the frame has moved. They matter most when they show up together with cracks.
    Monitor or call?
    Call if they show up along with new cracks or sloping floors. The TexasInspector buyer's guide calls it serious if an emergency-exit door can't be opened by a child.

    Sources: TexasInspector buyer's guide (PDF).

  • Offset slab crack, or wider than about 1/4 inch

    Looks like
    A slab crack where one side sits higher than the other (an offset), or a crack wider than about 1/4 inch.
    Usually means
    Crack width alone isn't a pass/fail test, but engineers look at offset and growth, and an offset or wide crack is a reason for a closer evaluation.
    Monitor or call?
    Get a professional or engineer evaluation.

    Sources: ASCE Texas Section guidelines (2022, PDF); InspectAPedia damage guide.

Why Houston-area clay soil moves with the seasons

Katy sits on Lake Charles and Beaumont clays, which are rich in montmorillonite, a clay mineral that shrinks and swells a lot. These soils crack open when dry (Beaumont clay cracks can be wider than 1/2 inch).

Because the clay shrinks in summer drought and swells after rain, cracks in a house can open in summer and close again after rain, so judge a crack over a full season. Texas A&M AgriLife advises keeping soil moisture even around the house, for example with a soaker hose about 8 to 18 inches from the slab.

Sources: USDA soil series: Lake Charles; USDA soil series: Beaumont; Texas A&M AgriLife (PDF).

When to call a pro vs. monitor

Usually fine to monitor

A single hairline crack with no offset that isn't growing. Photograph it with a date and a ruler, and mark the ends in pencil.

Call a pro

Cracks that are growing, stair-step or diagonal cracks at several openings, cracks around 1/4 inch wide, or one side higher than the other. Also call if new cracks show up along with sticking doors or sloping floors. An independent inspection by a licensed professional engineer (P.E.) is separate from an inspection by a repair company, and Texas doesn't license foundation repair contractors.

Sources: InspectAPedia damage guide; InspectAPedia crack dictionary; ASCE Texas Section guidelines (2022, PDF).

When in doubt, have a structural engineer or a foundation pro take a look.

Insurance and foundation cracks: FAQ

Does homeowners insurance cover foundation cracks?

Usually not, for normal soil movement. The standard Texas homeowners policy (HO-B) excludes loss caused by "settling, cracking, bulging, shrinkage, or expansion of foundations," and Texas courts have held that the exclusion applies whatever the cause. Policies vary, so check yours with your agent. This is general information, not legal advice. Sources: Bentley v. National Standard, 507 S.W.2d 652 (Tex. App. 1974); Dimotsis v. State Farm Lloyds; Balandran v. Safeco, 972 S.W.2d 738 (Tex. 1998).

Is foundation damage from a plumbing leak covered?

It may be. Foundation damage caused by an accidental plumbing, HVAC, or appliance leak was held covered under the HO-B form, and the Texas Department of Insurance told insurers to pay such claims. Policies vary, so check yours with your agent. Sources: Balandran v. Safeco, 972 S.W.2d 738 (Tex. 1998); TDI Bulletin B-0032-97.

Does insurance cover cracks caused by clay soil shrinking and swelling?

Usually not. Texas courts have held that the HO-B foundation exclusion applies whatever the cause, including drought and soil movement. Check your own policy with your agent. Sources: Balandran v. Safeco, 972 S.W.2d 738 (Tex. 1998); Bentley v. National Standard, 507 S.W.2d 652 (Tex. App. 1974).

Finding a foundation repair company

If you decide to have a crack looked at, the Katy-area foundation repair directory lists 18 companies with the repair methods and warranty terms each one publishes.