Oklahoma foundation library

Oklahoma cities

City-by-city foundation conditions: the soils inside each city's limits, how much of it shrinks and swells, and local water, rock and permit facts.

• What are foundation conditions like in Ada, Oklahoma?About 32% of Ada sits on high shrink-swell soil and 39% has bedrock within 40 inches; Durant is the most common soil. Measured from USDA soil maps.
• What are foundation conditions like in Altus, Oklahoma?About 58% of Altus sits on high shrink-swell soil; Tillman is the most common soil. Measured from USDA soil maps.
• What are foundation conditions like in Alva, Oklahoma?About 17% of Alva sits on high shrink-swell soil; Hardeman is the most common soil. Measured from USDA soil maps.
• What are foundation conditions like in Anadarko, Oklahoma?About 8% of Anadarko sits on high shrink-swell soil; Pond Creek is the most common soil. Measured from USDA soil maps.
• What are foundation conditions like in Ardmore, Oklahoma?About 39% of Ardmore sits on high shrink-swell soil; Windthorst is the most common soil. Measured from USDA soil maps.
• What are foundation conditions like in Bartlesville, Oklahoma?About 35% of Bartlesville sits on high shrink-swell soil and 43% has a water table within 2 feet; Dennis is the most common soil. Measured from USDA soil maps.
• What are foundation conditions like in Bethany, Oklahoma?About 9% of Bethany sits on high shrink-swell soil; Konawa is the most common soil. Measured from USDA soil maps.
• What are foundation conditions like in Bixby, Oklahoma?Bixby is split between Arkansas River terraces and floodplain, where 42% of the land rates low shrink-swell, and Dennis clay uplands; sandstone ridges add shallow rock.

All 76 oklahoma cities

ZIP codes

Soil conditions by ZIP code across the Tulsa and Oklahoma City metros: expansive clay, shallow water, shallow rock and flood-prone ground, measured from USDA soil maps.

• What are foundation and soil conditions in ZIP code 73003 (Edmond)?In ZIP code 73003 (Edmond), about 36% of the land is high shrink-swell soil; Renthin is the most common soil.
• What are foundation and soil conditions in ZIP code 73007 (Edmond)?In ZIP code 73007 (Edmond), about 13% of the land is high shrink-swell soil and 60% has bedrock within 40 inches; Stephenville is the most common soil.
• What are foundation and soil conditions in ZIP code 73008 (Bethany)?In ZIP code 73008 (Bethany), about 17% of the land is high shrink-swell soil; Konawa is the most common soil.
• What are foundation and soil conditions in ZIP code 73012 (near The Village)?In ZIP code 73012 (near The Village), about 45% of the land is high shrink-swell soil; Renthin is the most common soil.
• What are foundation and soil conditions in ZIP code 73013 (Oklahoma City)?In ZIP code 73013 (Oklahoma City), about 31% of the land is high shrink-swell soil and 42% has bedrock within 40 inches; Stephenville is the most common soil.
• What are foundation and soil conditions in ZIP code 73020 (Choctaw)?In ZIP code 73020 (Choctaw), about 6% of the land is high shrink-swell soil and 44% has bedrock within 40 inches; Stephenville is the most common soil.
• What are foundation and soil conditions in ZIP code 73025 (near Edmond)?In ZIP code 73025 (near Edmond), about 42% of the land is high shrink-swell soil and 40% has bedrock within 40 inches; Renthin is the most common soil.
• What are foundation and soil conditions in ZIP code 73026 (Norman)?In ZIP code 73026 (Norman), about 11% of the land is high shrink-swell soil and 48% has bedrock within 40 inches; Stephenville is the most common soil.

All 103 zip codes

Warning signs

What cracks, sticking doors, sloping floors and water problems usually point to.

• Are cracks in a garage or house slab a foundation problem?Most are concrete shrinkage and not structural; a crack matters when one side is higher, it keeps widening, or it lines up with signs like sloping floors.
• Are drywall nail pops and tape joint cracks a foundation problem?Usually not. They are most often caused by wood framing drying and shrinking, and point to the foundation only when other signs line up.
• Are sticking windows or cracked glass a foundation sign?They are possible signs of foundation movement but do not identify a cause alone. The whole-house pattern and an elevation survey separate it from other causes.
• Can a high water bill mean a leak affecting my foundation?A rising bill with no change in use usually means a leak. A leak under a slab can wet expansive clay and push part of the floor up.
• Can slow drains or sewer backups signal foundation movement?On expansive clay, soil movement can break buried drain pipes and a leaking drain can make the slab heave, so the two are often checked together.
• Do sticking doors or tapered door gaps mean foundation movement?They can. Out-of-square door frames are a listed sign of possible foundation movement, but the pattern across the house and a floor survey decide the cause.
• Is a vertical crack in brick veneer a foundation problem?A vertical crack near a corner, offset or long wall is often brick expansion. Tapered cracks, or ones at an addition, more likely involve the foundation.
• What causes a hump in the middle of a slab floor?Usually heave: soil under the area swells and pushes the slab up, from slow moisture build-up, a plumbing leak or removal of a large tree on expansive clay.

All 34 warning signs

Causes

Why foundations move in Oklahoma: shrinking and swelling clay, trees, leaks, fill, erosion and more.

• Can a foundation crack because it was built wrong?Yes. Thin beams, missing or misplaced steel, weak concrete or a poor pad can leave a foundation unable to bridge ordinary soil movement.
• Can a plumbing leak under a slab cause a floor hump?Yes. A supply or drain leak under a slab on expansive clay wets the soil, which swells and pushes up a local floor hump with cracks radiating from it.
• Can earthquakes damage Oklahoma homes and foundations?Yes. Strong shaking can crack chimneys, brick and masonry walls. Most Oklahoma quakes are too small to cause damage, but the larger 2016 events did.
• Can removing a tree make my foundation heave?Yes. A large tree can dry the clay under a house for years; once it is removed, water returns and the clay slowly swells and pushes up what sits on it.
• Can tree roots cause foundation settlement on Oklahoma clay?Yes. Roots under a foundation can dry and shrink expansive clay, so the side or corner nearest the tree settles, worst in summer and drought.
• Can vibration from construction or blasting crack a house?Blasting, pile driving or heavy equipment can stress finishes and lengthen existing cracks, but most Oklahoma home cracking traces to soil movement.
• How does crawl space moisture cause wood rot and sagging floors?Water and humid air in a crawl space raise wood moisture until decay fungi grow, weakening sills, joists and beams so floors feel soft, bouncy or sag.
• How does erosion leave voids under a foundation or slab?Runoff, flooding or a leaking pipe can carry soil from beside or under a foundation, leaving a void where the concrete above can crack or settle.

All 26 causes

Repairs

How each repair method works, what it fixes and where it falls short.

• Do root barriers and moisture barriers protect foundations?Buried root and moisture barriers keep roots and seasonal drying away from soil under a foundation. They support other repairs but cannot lift a foundation.
• How are bowing or cracked basement walls repaired?Repairs strengthen, brace, anchor or replace the wall, paired with drainage, since soil pressure, swelling clay and trapped water cause the damage.
• How are interior slab piers installed by tunneling or coring?Crews reach soil under the slab interior by tunneling from outside or coring through the floor. Interior piers address settlement only, not a heaved center.
• How are sagging crawl space floors repaired?Crawl space repair adds supports on proper footings, shims, added beams, reinforced joists and new sill plates, designed to be adjusted as Oklahoma clay moves.
• How are under-slab plumbing leaks found and repaired?Supply leaks are found with a water-meter check and drain leaks with a hydrostatic test and camera; in Oklahoma the repair is licensed plumbing work.
• How do drilled bell-bottom piers work on expansive clay?A drilled bell-bottom pier is a reinforced concrete column with a widened base set below the active clay and anchored to minimize uplift from swelling clay.
• How do helical piers support a foundation?A steel shaft with screw plates is turned into the ground and bracketed to the foundation. It installs without building weight, suiting light loads and uplift.
• How do mudjacking and polyurethane foam lift a sunken slab?Both pump material under a slab, cement slurry or expanding foam, to fill gaps and lift it, but they rest on the same soil and do not stop clay movement.

All 20 repairs

Case studies

Real Oklahoma foundation jobs and engineer evaluations: what was found, why, and what repair was specified. Names and addresses removed.

• How deep did steel piers go across a large Tulsa apartment complex?Across 396 logged piers at a 34-building Tulsa complex, refusal depth ranged 2 to 40 ft, median 12 ft, at a median 9,000 psi driving pressure.
• How did downspouts help crack the foundation of a 2007 Bristow house?Downspouts discharging at the foundation eroded two corners. The engineer called it a defect and specified piers, slab leveling and downspout extensions.
• What did an engineer specify for a previously piered Sand Springs house?21 perimeter steel piers at least 10 ft below the footing, 10 to 15 interior helical piers with foam, and a duct camera check, for active clay and additions.
• What did an engineer specify for a south Tulsa slab with failing walls?4 perimeter steel piers, 10 to 15 interior helical piers with foam, crack stitching, new retaining walls and channel drains, for active clay movement.
• What did an engineer specify for an 80-year-old Tulsa basement house?15 exterior steel piers, a rebuilt stairwell wall, new beams and posts, porch foam and a new sump pump, for age-related settlement and basement water.
• What did an engineer specify when old piers stopped holding in south Tulsa?Cracks reopened along a previously piered garage wall; the engineer said to repressurize those piers or replace them, add 3 new piers, and level the slab.
• Why did a 1928 Tulsa basement wall need a full rebuild?Years of lateral soil and water pressure bowed the lower block wall inward, so the engineer ruled out crack repair or bracing and called for a rebuild.
• Why did a 1953 Tulsa crawl space home need drainage work along with piers?Surface water was entering the crawl space and old concrete piers at one corner had stopped holding; the engineer specified steel piers plus drainage fixes.

All 18 case studies

Foundation types

Slabs, crawl spaces, basements and how each one fails.

• How are manufactured homes set on piers in Oklahoma?They rest on a steel chassis carried by concrete-block piers on small pads, held by anchors. Shallow pads ride up and down as Oklahoma clay swells and shrinks.
• How do slab-on-grade foundations move on Oklahoma clay?The slab moves as clay under its edges or center gains or loses moisture, and the shape of that movement decides which repair, if any, fits.
• How does a pier and beam crawl space foundation work?The house sits on a raised wood floor over a crawl space, with a perimeter footing and wall and interior piers carrying beams and joists.
• What are stem wall and grade beam foundations?A stem wall is a short wall on a continuous footing. A grade beam spans drilled piers set below swelling clay, with a gap under it so clay cannot lift it.
• What is a post-tensioned slab and does it move on Oklahoma clay?A PT slab is reinforced with steel tendons pulled tight after pouring; used on expansive clay, it still moves when clay swells or shrinks unevenly.
• Why do driveways, patios and sidewalks move in Oklahoma?Flatwork is thin, lightly loaded and sits on the soil, so swelling clay lifts it and drying or washed-out soil lets it drop more readily than the house.
• Why do Oklahoma basement walls crack and bow?Most trouble comes from sideways pressure: clay that swells when wet and water that builds up in the backfill behind the wall.

Guides

Inspections, surveys, drainage, trees, weather and working with engineers.

• Are there gypsum sinkholes in western Oklahoma?Yes, in places. Gypsum near the surface can dissolve in groundwater, leaving voids that let the ground above sag or collapse.
• Can an under-slab plumbing leak move an Oklahoma foundation?Yes. A leak under a slab can make expansive clay swell and lift the floor or soften and wash out looser soil, so the leak must be fixed for a lasting repair.
• Can trees damage a foundation in Oklahoma clay soil?Large trees rarely push a foundation. They mainly cause damage by drawing water from clay, which shrinks and lets the nearby part of the house settle.
• How can Oklahoma Mesonet soil moisture data explain foundations?The Oklahoma Mesonet is a free statewide network reporting soil moisture. Its shallow readings show whether ground is drier or wetter than usual, as trends.
• How deep do foundation piers need to go in Oklahoma shale?Shale weathers top-down into clay; piers aim for firmer material below the shrink-swell layers, and Oklahoma push pier records run about 8 to 16 feet.
• How do erosion, creeks and slopes threaten Oklahoma foundations?Runoff can undermine slab edges, creeks can cut into banks, clay on slopes can creep, and underground flow can carry soil away and leave voids.
• How do freezes and frost affect Oklahoma foundations?Frost is a secondary issue in most of Oklahoma; freezes mainly affect porches, steps, driveways and plumbing, more so in the northwest and Panhandle.
• How do Oklahoma drought and wet cycles move foundations?Oklahoma clay shrinks in drought and swells when wet, so foundations drop at the edges during drought and can be pushed back up when heavy rain returns.

All 37 guides

Oklahoma soils

The soil series under Oklahoma homes and what each means for a foundation.

• What is Abilene soil and how does it affect Oklahoma foundations?Abilene is a deep, well-drained terrace soil of southwest Oklahoma with a 35 to 50 percent clay subsoil that shrinks and swells with the seasons.
• What is Apperson soil and how does it affect Oklahoma foundations?Apperson is a smectite clay Vertisol over hard limestone 40 to 60 inches down that cracks and swells seasonally, so heave and settlement are both concerns.
• What is Bates soil and how does it affect Oklahoma foundations?A well-drained, loamy eastern Oklahoma soil over soft sandstone at 20 to 40 inches. It swells less than nearby clays, so drainage, erosion and fill matter most.
• What is Bernow soil and how does it affect Oklahoma foundations?Bernow is a deep, well-drained loamy soil from Cretaceous sandstone with about 20 to 32 percent clay, so water, erosion and fill matter most.
• What is Bethany soil and how does it affect Oklahoma foundations?Bethany is a very deep central Oklahoma soil with a silty clay subsoil of 35 to 45 percent clay, with a subsoil rated moderate in shrink-swell, so homes can move seasonally.
• What is Chickasha soil and how does it affect Oklahoma foundations?Chickasha is a well-drained loamy soil over weakly cemented Permian sandstone at 40 to 60 inches; drainage, erosion and fill matter more than swelling.
• What is Choteau soil and how does it affect Oklahoma foundations?Choteau is a very deep, somewhat poorly drained clayey soil with a perched water table 2.5 to 3 feet down from December through April.
• What is Clarksville soil and how does it affect Oklahoma foundations?A deep, cherty Ozark soil on steep slopes with fast-draining gravelly upper layers and clay 3 to 4.5 feet down; slope and runoff are the main concerns.

All 56 oklahoma soils

Geology

The rock layers under Oklahoma and how deep firm ground usually is.

• How do cherty limestone soils affect NE Oklahoma foundations?Weathered cherty limestone leaves very gravelly soils, dense fragipans and some karst, so foundation concerns center on water, voids and rocky digging.
• How do Oklahoma river floodplain and terrace soils affect homes?Floodplain and terrace deposits range from soft wet clay to sandy dunes and expansive claypans, so the soil series, not the river, predicts behavior.
• How do Ouachita Mountain rocks affect southeast Oklahoma homes?Tightly folded sandstone, shale and chert form steep slopes with thin, rocky soils, so slope movement, erosion and fill matter more than clay swell.
• How do Panhandle Ogallala and loess soils affect foundations?Panhandle soils formed in Ogallala deposits capped by loess and sand. They are dry most of the year, so movement follows sudden moisture changes.
• How do Pennsylvanian shale clays affect Oklahoma foundations?Pennsylvanian shale under Tulsa and eastern Oklahoma weathers into poorly drained clays that hold perched water and often swell and shrink strongly.
• How do Tulsa-area sandstone ridges affect Oklahoma foundations?The sandstone forms shallow, loamy, well-drained soils, so slopes, fill, erosion and uneven rock matter more than clay swell on these lots.
• How do western Oklahoma red beds affect foundation soils?Soft red sandstone and siltstone form shallow silty soils, while claystone and old river clays form expansive clay soils.
• How do Wichita granite and outwash affect Lawton-area foundations?Around the Wichita Mountains, soils formed in granite outwash over red clay, such as Foard, are sodium-rich, very slowly permeable and prone to shrink-swell.

All 15 geology

Regions

Foundation conditions across Oklahoma, from the Panhandle to the Ouachitas.

• What causes foundation problems in the Tulsa, Oklahoma metro?Most Tulsa foundation movement comes from shale clays that swell and shrink with about 41 inches of yearly rain; sandstone hills and floodplains add others.
• What soils affect foundations in east-central Oklahoma?A wet region of shale, sandstone ridges and floodplains; many soils hold a seasonal high water table, and floodplain clays such as Osage are smectitic Vertisols.
• What soils affect foundations in the Oklahoma Panhandle?The driest region, about 17 to 18 inches of rain in the west; soils formed in wind-deposited loess, and some, like Richfield, have clay subsoils that swell.
• What soils cause foundation problems in north-central Oklahoma?Red prairie clays over Permian shale, such as Renfrow, Kirkland and Tabler, shrink and swell strongly, while loamy Pond Creek and Grant soils are less reactive.
• What soils cause foundation problems in northeast Oklahoma?Cherty Ozark soils and karst around Grand Lake, Grove and Tahlequah, plus shrink-swell shale clays and perched water toward Vinita and Pryor.
• What soils cause foundation problems in northwest Oklahoma?Northwest Oklahoma sits on Permian red beds with gypsum and salt that can form sinkholes, slow-draining clays such as Vernon, and loamy soils on soft rock.
• What soils cause foundation problems in south-central Oklahoma?Shale clays near Durant crack deeply when dry, the Arbuckles hold limestone karst, and sandy and Red River soils bring drainage and flooding concerns.
• What soils cause foundation problems in southeast Oklahoma?Steep, rocky Ouachita slopes, Cretaceous shale clays that shrink and swell, flood-prone Red River sands and the state's heaviest rainfall.

All 10 regions

Codes, insurance and real estate

Permits, contractor rules, insurance claims and disclosure in Oklahoma.

• Do you need a permit for foundation repair in Oklahoma?It depends on the city. Oklahoma uses the 2024 IRC statewide, cities run their own permit offices, and the state does not license foundation repair.
• Does homeowners insurance cover foundation damage in Oklahoma?Standard policies usually exclude settling or soil movement. Earthquake damage needs a separate endorsement, and flood policies exclude earth movement.
• Does insurance cover slab leak foundation damage in Oklahoma?A slab leak can raise or lower part of a house, but insurance treatment of leak-related settlement is unsettled, with courts split on the settling exclusion.
• How are foundation problems handled in an Oklahoma home sale?They surface through the seller's disclosure form, the buyer's inspection, the contract's repair window and lender rules; the 2026 form asks about past repairs.
• How do you choose a foundation repair contractor in Oklahoma?Oklahoma has no state foundation repair license. Check city registration and insurance, permits, an engineer's plan, written scope and warranty, and complaints.
• What permits, licensing and frost depth apply in Oklahoma?Oklahoma leaves frost depth to each city or county, with published values about 18 inches, and does not license foundation repair as a trade.
• What safety rules apply to foundation repair work in Oklahoma?Federal OSHA rules cover trench protection, excavation inspections and silica dust from concrete cutting; heat and crawl spaces add other hazards.
• What should an Oklahoma foundation repair contract cover?Scope of work, what lift means, exclusions and drainage duties afterward. Many in-home sales allow 3-day cancellation, and Oklahoma liens have strict deadlines.

Oklahoma data

Borings, drought, earthquakes, floods and soil lab values from public records.

• Does insurance pay for Oklahoma earthquake foundation damage?Oklahoma quake claims have been paid at a low rate: in 2014 about 100 were filed and eight paid, and masonry veneer and chimneys are often excluded.
• How deep does Oklahoma soil dry out during drought?Oklahoma Mesonet research puts the active zone of seasonal moisture change at about 0.5 to 4 meters (1.6 to 13 feet), depending on soil and climate.
• How deep is bedrock in Tulsa and Oklahoma City?Public borings show rock about 9 to 15 feet under upland shale in Tulsa; in Oklahoma City, Hennessey shale ran 2 to 41 feet and Garber sandstone 20 to 95.
• How deep is rock under Tulsa and Oklahoma City?In upland Tulsa, rock is often 2 to 15 feet down; near creeks and the river, 20 to 35 feet or more. South of OKC, borings hit shale at 15.5 to 25 feet.
• How did Oklahoma's foundation code change for homes in 2022?Oklahoma's 2018 IRC rule, effective September 14, 2022, added rebar to all footings, set anchor bolt spacing and barred trenching into footing support soil.
• How does the moisture index change across Oklahoma?The Thornthwaite Moisture Index weighs rainfall against evaporation. Oklahoma gets drier east to west, and drier climates generally drive soil drying deeper.
• How far should trees be planted from a house in Oklahoma City?Oklahoma City's planting guide keeps medium and large trees at least 30 feet from buildings; most roots are shallow but spread well beyond the canopy.
• What are Oklahoma's pier and anchor rules for manufactured homes?New homes follow the federal standard or maker's instructions. Used homes need block footings, piers no more than 6 feet apart, limited shims and anchor ties.

All 13 oklahoma data