The short answer
Mark the ends of the crack and the date, then check whether a door, a window, or the floor moved with it. A hairline that does not grow can often be watched. A stair-step crack, a crack that widens, or a bowing wall is a reason to get a closer look. Ask who is licensed for the job in your city, and ask whether an engineer should see the soil first.
On this page
A crack after a dry month does not wait for a plan. The order still matters. Find what moved first, then decide what you can watch and what needs a written look.
Mark the crack and check the doors
Write the date next to each end of the crack, or tape a dated photo to the wall. Come back after the next long dry spell or the next hard rain. When is a foundation crack serious? is the short version of what to watch.
Open the doors and windows on that wall. A latch that misses, or a floor that sends a marble toward one corner, is a sign the frame moved with the crack. That still does not name the soil.
Read the soil under the house
The USGS swelling-clays map, Map I-1940, shows where swelling clays are common in the conterminous United States. It is a national map. It is not a report on your lot.
In the Jackson belt, Mississippi Geological Survey Circular 1 says Yazoo clay expands when it takes on water and shrinks when it dries, and that this movement cracks foundations and pavements. In Colorado, the Colorado Geological Survey swelling-soils guide says swelling soil can damage houses slowly, and that houses on the same street can move at different times.
Yazoo clay under Jackson houses and heaving bedrock in Colorado Springs keep those local facts. Doing foundation work in Tulsa? The 2024 code is in force. and Waco slabs on Houston Black clay do the same for those cities.
Decide who should look
A hairline that does not grow, and that does not move a door, can often be watched. A stair-step crack, a crack that widens, a sloping floor, or a bowing wall is a reason to get a closer look.
The City of Waco permit page says a foundation on expansive soil, or soil with a plasticity index of 15 or greater, shall be investigated and designed by a registered engineer. That is a Waco rule. Other cities write their own. Do I need an engineer before a contractor? walks through that split.
Ask what insurance will and will not pay
FEMA's earth-movement note says a National Flood Insurance Program policy excludes earth movement, even when floodwater caused the soil to move, and lists land subsidence and sinkholes among the examples. A homeowners policy is a different contract. Does homeowners insurance cover foundation repair? keeps those two apart.
Photograph the wall before anyone digs. A company you hire cannot decide coverage.
When a contractor starts to make sense
A national cost range is not a bid for your house. How much does foundation repair cost? keeps the table.
A crew starts to make sense when the crack is growing, a door or a floor moved with it, or a city rule says the footing needs an engineered design. How to choose a foundation contractor is the checklist for that call.
Questions people ask next
Sources
- USGS: Swelling clays map of the conterminous United States, Map I-1940ngmdb.usgs.gov
- Mississippi Geological Survey Circular 1: Yazoo claygeology.deq.ms.gov
- Colorado Geological Survey: SP-43, A Guide to Swelling Soilscoloradogeologicalsurvey.org
- FEMA: Earth movement decision on a flood claimfloodsmart.gov
- City of Waco: Residential Construction Permitswaco-texas.com
Who wrote this page
- Written by
- Footing Fix editorial staff. Who runs this site
- Licensed professional
- None. No licensed structural engineer or foundation contractor has checked this page.
Talk through the crack you are seeing
Footing Fix and one or more foundation repair companies that serve your area may call and text you to talk through what you are seeing. Asking is free, and the call is not a bid.