Terralox / For homeowners
Cracks, sticking doors, sloping floors? Find out what they mean before anyone sells you a repair.
Terralox is a free, sourced library about Oklahoma foundations. It explains what you're seeing, what's in the ground under your city and ZIP code, and what to know before you call a company. Every answer cites its source, and nothing here is selling a repair.
Start with what you're seeing
- Diagonal drywall cracks at doors and windows
- Stair-step cracks in brick and brick pulling away from frames
- Doors that stick or have tapered gaps
- Floor tile cracking in a line and gaps under baseboards
- Cracks that open and close with the seasons
- Bouncy or soft floors over a crawl space
- Not sure? The symptom matrix and crack pattern guide match what you see to likely causes.
Cracks alone don't prove a foundation is failing. Engineering guidelines treat them as clues to check against floor elevation measurements, and how wide they are, how many there are and whether they're growing matter most. See heave versus settlement: the fix for one can make the other worse.
Know what's under your house
Oklahoma ground changes from town to town and even from one ZIP code to the next. Each city page and ZIP-code page shows how much of the area sits on expansive clay, shallow water, shallow rock and flood-prone soil, measured from USDA soil maps, with what that means for houses.
- Compare all 75 Oklahoma cities of 5,000+ people
- Tulsa area: Tulsa, Broken Arrow, Owasso, Bixby, Jenks, Sand Springs, Sapulpa, Claremore
- Oklahoma City area: Oklahoma City, Edmond, Norman, Moore, Yukon, Mustang, Midwest City
- Know your home's age? What foundation your house likely has, by decade built
Why Oklahoma foundations move
Most movement comes from clay soil that swells when it gets wet and shrinks when it dries, made worse by water and trees around the house. Oklahoma clay typically swells in wet springs and shrinks in hot, dry summers, so cracks often open in late summer and close up in spring. Start with why foundations move, in plain English, then:
- Edges lifting after wet spells and edges dropping in drought
- Trees and roots, plumbing leaks under the slab and yard drainage
- When foundations move during the year
What you can do now
- Keep water moving away from the house: grading and downspouts and drainage repairs
- Water evenly in drought and keep trees in check: root barriers and moisture control
- Write down crack widths and dates, and take photos from the same spot. A record over months shows whether movement is ongoing; see monitoring.
- Rule out a leak if one area is getting worse fast: leak detection and repair
Before you call a company
Oklahoma doesn't license foundation repair as a state trade, so it's on you to check registration, insurance, permits and the written scope and warranty.
- How to choose a foundation repair contractor
- What affects the cost and which repair fits which problem
- What the contract and warranty should say, including lien rules and your right to cancel
- When to get an independent engineer: an engineer, not the repair company, controls an engineered repair plan
- What insurance covers: standard policies usually exclude soil movement, so the cause of the damage decides coverage
- Whether you need a permit
Talk it through
- TerraBrain asks a few plain questions about your house and walks you to the likely cause and the repair that fits, with sources.
- The Homeowner Hub is a board where Oklahoma homeowners compare what they ran into, under a board name.
- Ready for estimates? The company map shows foundation companies; the ones that pay to be there are marked Sponsored. Terralox doesn't rank or recommend them; get more than one opinion.
- Buying or selling? The same map shows realtors too; paid listings are marked Sponsored.
- Doing a small repair or drainage fix yourself? The map also shows material suppliers, including free basic listings for stores near you. Check the library first for what the repair actually needs.
Common questions
Is a crack in my house a sign of foundation trouble?
Not by itself. Cracks, sticking doors and sloping floors are clues to check against floor elevation measurements, not proof of failure. Width, number and whether they're growing matter most. Read more.
Why do my cracks open and close during the year?
Oklahoma clay swells in wet springs and shrinks in hot, dry summers, so cracks often open in late summer and narrow in spring. Read more.
Does homeowners insurance cover foundation repair?
Standard policies usually exclude damage from settling or soil movement. Earthquake damage needs a separate endorsement, and flood policies exclude earth movement. Read more.
Do I need an engineer or a repair company?
An engineer gives an independent, sealed opinion on the cause and the fix; Oklahoma's engineering board guidelines put the engineer, not the repair company, in control of an engineered repair plan. Read more.
Does Oklahoma license foundation repair companies?
No. Check city contractor registration, insurance, permits and a written scope and warranty. Read more.
Is Terralox free?
Yes. The library, the city and ZIP-code pages and TerraBrain are free to read; a free account adds more TerraBrain questions and the Homeowner Hub. Buying or selling? See for realtors, which covers disclosure, inspections and the sale timeline.