Regions: every question answered
84 questions with short answers. Each links to the full, sourced explanation.
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 is the Tulsa climate like?
- Tulsa's 1991–2020 normal precipitation is about 40.96 inches a year. May is the wettest month at about 5.73 inches, and January and February are the driest at about 1.6 inches each. That pattern matters because clay soil changes volume as its moisture changes.
- What are the three ground settings in the metro?
- Much of the gently rolling ground in the metro has soils formed from Pennsylvanian shale, an old layered mudrock. Examples include:
- Which soil series are common in Tulsa?
- The Tulsa soil series guide covers more series, including Okemah, Coweta, Bates and Apperson.
- Tulsa metro soils: How does rock in the soil survey compare to pier depth?
- Soil surveys only describe roughly the top 5 feet, so "depth to rock" in a survey is not where a deep foundation pier stops.
- Which moisture practices matter in Tulsa?
- Because so much Tulsa movement is moisture-driven, the ASCE homeowner guide lists practical steps for clay sites:
- Why do Tulsa houses move so much in spring and late summer?
- Much of the metro sits on clay soils weathered from shale that swell when wet and shrink when dry. May is normally the wettest month, and summer drying follows, so the soil under a house edge can go through a large wet-dry swing each year.
- Is there rock close to the surface in Tulsa?
- On sandstone hills and ridges, soil surveys record rock within about 4 to 20 inches in soils such as Collinsville. In the shale lowlands, soils like Dennis and Summit are more than 60 inches deep, so rock depth varies a great deal from one neighborhood to the next.
- How deep do steel piers usually go in Tulsa?
- Field records from Tulsa installations show a median refusal depth of about 12 feet, with most exterior piers between roughly 8 and 16 feet. The soil survey 'depth to rock' is not the same as the depth where a pier stops.
- What is perched water and why does it matter in Tulsa?
- Perched water is a temporary, shallow water table that sits on top of a dense clay or shale layer. Several Tulsa soils hold perched water from late fall through spring, which can wet crawl spaces and swell clay under slab edges.
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.
- East-central Oklahoma: What is the climate like?
- USDA descriptions for the region's soils list mean annual precipitation of roughly 35 to 47 inches, with typical values near 39 to 41 inches, and mean annual temperatures of about 55 to 64 °F.
- East-central Oklahoma: What is the ground made of?
- Much of the region is underlain by Pennsylvanian shales with thin sandstone and siltstone layers.
- East-central Oklahoma: What foundation problems are common?
- Perimeter wetting heave where shale clays stay wet through winter and spring; Crawl space moisture and wood decay under homes on soils with shallow seasonal water; Slope creep on steeper shale hillsides.
- East-central Oklahoma: Why are soils around Muskogee and Okmulgee often wet in spring?
- Several common soils formed from Pennsylvanian shale have a seasonal high or perched water table within about 1 to 3 feet of the surface in winter and spring, according to USDA soil descriptions.
- Which east-central Oklahoma soils swell the most?
- Floodplain clays such as Osage are classified as Vertisols, with smectitic clay and continuous slickensides from about 13 to 60 inches deep.
- How much rain falls in east-central Oklahoma?
- USDA descriptions for the region's soils give mean annual precipitation of roughly 35 to 47 inches, with typical values around 39 to 41 inches.
- Are landslides a concern in eastern Oklahoma?
- The Oklahoma Geological Survey reports that most of the state's landslides occur in the eastern third, where the climate is wetter and the terrain steeper.
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.
- Oklahoma Panhandle: What is the climate like?
- Oklahoma's climate grades from humid subtropical in the east to semi-arid in the west, and annual precipitation drops to about 17 inches in the far western Panhandle.
- Oklahoma Panhandle: What is the ground made of?
- Loess is silt deposited by wind. Richfield soils are very deep, well drained soils formed in calcareous loess about 3 to more than 10 feet thick, on nearly level tablelands with slopes of 0 to 6 percent. Their subsoil contains 35 to 42 percent clay and is classified as smectitic.
- Oklahoma Panhandle: What foundation problems are common?
- Hydrocollapse — some dry, loose wind-deposited soils can compact suddenly when first soaked; see collapsible and loess soils; Swelling on wetting in smectitic clay subsoils such as Richfield, especially near lawn irrigation, leaks or ponding; Frost heave of shallow footings and flatwork in colder winters.
- How dry is the Oklahoma Panhandle?
- It is the driest part of the state. Statewide research notes annual precipitation of about 17 inches in the far western Panhandle, and USDA descriptions for Panhandle soils give typical values near 18 inches.
- Oklahoma Panhandle: What is loess?
- Loess is silt-sized sediment deposited by wind. In the Panhandle, Richfield soils formed in calcareous loess 3 to more than 10 feet thick on flat tablelands.
- Do Panhandle soils shrink and swell?
- Some do. Richfield soils have 35 to 42 percent clay in the subsoil with smectitic mineralogy, a clay family with high shrink-swell potential. Sandier soils formed in wind-blown sediments, such as Dalhart, have less clay.
- Why does it matter that Panhandle soils are so dry?
- Soils that stay dry for long periods can react strongly when they are wetted by irrigation, leaks or poor drainage, through swelling in clay or compaction in some loose wind-deposited soils.
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.
- North-central Oklahoma soils: What is the climate like?
- USDA soil descriptions for the region list mean annual precipitation from roughly 26 to 38 inches and mean annual temperatures of about 57 to 64 °F.
- North-central Oklahoma soils: What is the ground made of?
- The region is mapped by USDA as Major Land Resource Area 80A, the Central Rolling Red Prairies.
- North-central Oklahoma soils: What are the common foundation problems?
- Perimeter drying settlement on Renfrow, Kirkland and Tabler clays during drought; Tree-root desiccation settlement where trees grow close to homes on these clays; Heave when dried clays rewet after drought or tree removal.
- What soils cause foundation movement around Enid and Ponca City?
- Clay soils of the Central Rolling Red Prairies, such as Renfrow, Kirkland and Tabler, have vertic or vertic-like properties including cracking and slickensides, which indicate strong shrink-swell behavior.
- Are all soils in north-central Oklahoma high shrink-swell?
- No. Soils such as Pond Creek, Grant and Kingfisher are loamy, formed in silty material or siltstone and shale, and their USDA descriptions do not list vertic properties.
- How much rain falls in north-central Oklahoma?
- USDA descriptions for the region's main soils list mean annual precipitation of roughly 26 to 38 inches, with typical values in the low to mid 30s.
- North-central Oklahoma soils: What is a slickenside?
- A slickenside is a polished, grooved surface inside a clay soil, formed when the clay swells and blocks of soil shear past each other. It is a field sign of high shrink-swell clay.
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.
- Northeast Oklahoma soils: What is the climate like?
- USDA descriptions for the region's soils give mean annual precipitation of about 35 to 47 inches, with typical values in the low 40s, and mean annual temperatures of about 54 to 65 °F.
- Northeast Oklahoma soils: What is the ground like?
- USDA places these soils in the Ozark Highlands and Ozark land resource areas, whose range includes Oklahoma. The bedrock is described on Mississippian cherty limestone.
- Northeast Oklahoma soils: What are the common foundation problems?
- Crawl space moisture and wood decay where perched water and high rainfall keep soil wet; Perimeter wetting heave and seasonal movement on Summit and Osage clays; Slope creep and erosion on steep Ozark hillsides. Most Oklahoma landslides occur in the eastern third of the state.
- What makes Ozark soils near Grand Lake different for foundations?
- Ozark soils such as Clarksville and Nixa formed from cherty limestone or dolomite and contain large amounts of chert gravel, often 35 to 80 percent by volume in parts of the profile. They are on hilly ground with slopes up to 35 to 70 percent.
- Does northeast Oklahoma have sinkholes?
- The Oklahoma Geological Survey reports limestone and dolomite karst mainly in the Ozark region, among other areas. Karst forms where groundwater dissolves soluble rock, creating caverns and sinkholes.
- Are there expansive clays in northeast Oklahoma?
- Yes, especially on the prairie side toward Vinita and Pryor. The Summit series, formed from Pennsylvanian shale, has smectitic clay, slickensides and deep, wide cracks that form in summer.
- Why do some northeast Oklahoma yards stay soggy in spring?
- Soils such as Parsons have a perched water table 6 to 18 inches below the surface from about December through April, above a dense clay subsoil, and Nixa has a dense fragipan layer that slows water.
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.
- Northwest Oklahoma soils: What is the climate like?
- USDA descriptions for the area's main soils list mean annual precipitation of about 20 to 30 inches, typically near 25 inches, and mean annual temperatures of about 57 to 65 °F.
- Northwest Oklahoma soils: What is the ground made of?
- USDA maps most of this area within the Central Rolling Red Plains land resource area.
- Northwest Oklahoma soils: What are the common foundation problems?
- Karst subsidence and sinkholes where gypsum or salt lies at shallow depth; Perimeter drying settlement on Vernon clays during long droughts; Settlement and erosion problems on loose sands and steep escarpments.
- Are there sinkholes in northwest Oklahoma?
- Gypsum and shallow salt deposits occur in many areas of western Oklahoma, according to the Oklahoma Geological Survey. These rocks dissolve in circulating groundwater and can form caverns and sinkholes.
- How much rain does northwest Oklahoma get?
- USDA descriptions for the main soils around Woodward give mean annual precipitation of about 20 to 30 inches, with a typical value near 25 inches.
- Which northwest Oklahoma soils are clay?
- Vernon soils are moderately deep clays from Permian red-bed claystone with very slow permeability, and some layers contain soluble salts and sodium. Woodward and Quinlan soils are loamy over soft sandstone or siltstone.
- Northwest Oklahoma soils: Is building on sand dunes a foundation concern?
- Tivoli soils are deep, excessively drained wind-blown sands on dunes with slopes up to 45 percent. They do not shrink and swell like clay, but loose sand on slopes raises different concerns, including erosion and support near slopes.
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.
- South-central Oklahoma soils: What is the climate like?
- Rainfall rises from west to east across the region. USDA descriptions give mean annual precipitation of about 33 to 39 inches for Zaneis soils, and about 37 to 45 inches for Durant soils. Mean annual temperatures run about 59 to 66 °F. See drought and wet cycles.
- South-central Oklahoma soils: What is the ground made of?
- Durant soils are very deep, moderately well drained clays weathered from Cretaceous clayey shale and claystone on broad, gently sloping ridges. Key facts from the USDA description:
- South-central Oklahoma soils: What are the common foundation problems?
- Perimeter drying settlement on Durant and similar clays during drought; Center heave when water collects under slabs on the same clays; Flood and erosion exposure on Red River and creek floodplains.
- South-central Oklahoma soils: Why are foundations around Durant prone to movement?
- Durant soils formed from Cretaceous clayey shale and claystone, have smectitic clay and very slow permeability, and develop cracks wider than 1 cm and deeper than 30 inches in dry periods, according to USDA.
- South-central Oklahoma soils: Are there sinkholes in the Arbuckle Mountains area?
- The Oklahoma Geological Survey reports limestone and dolomite karst in the Arbuckle Mountains. Karst forms where groundwater dissolves soluble rock, which can create caverns and sinkholes.
- How much rain falls in south-central Oklahoma?
- USDA descriptions give mean annual precipitation of about 37 to 45 inches for Durant soils and 33 to 39 inches for Zaneis soils farther west in the region.
- Does south-central Oklahoma have earthquakes?
- The Oklahoma Geological Survey lists Love and Carter Counties among the state's principal seismic areas, and gives typical Oklahoma earthquake magnitudes of about 1.8 to 2.5.
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.
- Southeast Oklahoma soils: What is the climate like?
- Oklahoma's climate grades from humid subtropical in the east to semi-arid in the west, and annual precipitation reaches about 56 inches in the far southeast.
- Southeast Oklahoma soils: What is the ground like?
- The bedrock of the mountains is described on Ouachita folded rocks.
- Southeast Oklahoma soils: What are the common foundation problems?
- Slope creep and lateral movement on steep Ouachita hillsides; Crawl space moisture and wood decay in a high-rainfall climate; Erosion and washout voids where heavy runoff reaches foundations.
- Is southeast Oklahoma the wettest part of the state?
- Yes. Statewide research notes annual precipitation of about 56 inches in the far southeast, compared with about 17 inches in the far western Panhandle.
- Southeast Oklahoma soils: Are landslides and slope movement a concern in the Ouachitas?
- The Oklahoma Geological Survey reports that most Oklahoma landslides occur in the eastern third of the state, where a wetter climate and steeper, mountainous terrain favor them.
- Are there expansive clays in southeast Oklahoma?
- Yes. Clays such as the Durant series, whose type location is in Bryan County, formed from Cretaceous shale and claystone and have smectitic clay, very slow permeability and deep cracks in dry periods.
- Do Red River bottomland soils flood?
- Kiomatia soils on Red River natural levees are described by USDA as frequently flooded for brief periods in most years where they are not protected.
What soils cause foundation problems in southwest Oklahoma?
Southwest Oklahoma has deep clays such as Hollister and Tillman that crack more than 30 inches deep when dry, and Foard, a cracking clay with a sodium-rich subsoil.
- Southwest Oklahoma soils: What is the climate like?
- USDA descriptions for the region's clay soils list mean annual precipitation of about 22 to 32 inches and mean annual temperatures of about 57 to 65 °F. Toward Chickasha on the eastern side, soils list about 35 to 41 inches.
- Southwest Oklahoma soils: What is the ground made of?
- Most of the region lies in the Central Rolling Red Plains land resource area, where soils formed in clayey alluvium and Permian red beds.
- Southwest Oklahoma soils: What are the common foundation problems?
- Perimeter drying settlement and tree-root desiccation settlement on deep-cracking clays; Center heave and leak-related heave when water collects under slabs; Soil pulled away from the foundation and wide surface cracks in summer.
- Southwest Oklahoma soils: Why do foundations crack so much around Altus and Frederick?
- Many soils there, such as Hollister and Tillman, are deep clays with very slow or slow permeability whose cracks extend deeper than 30 to 48 inches in dry periods. Hollister is a Vertisol, the soil order defined by strong shrink-swell.
- Southwest Oklahoma soils: What is a sodic soil?
- A sodic soil has a high share of sodium on its clay. Foard soils, formed partly from old granitic outwash of the Wichita Mountains, have a sodium-rich (natric) subsoil within about 22 to 66 inches, with exchangeable sodium of about 15 to 25 percent in its lower layers.
- How much rain falls in southwest Oklahoma?
- USDA descriptions for the region's clay soils list mean annual precipitation of about 22 to 32 inches, while soils on the region's eastern side near Chickasha list about 35 to 41 inches.
- Is there gypsum in southwest Oklahoma?
- The Oklahoma Geological Survey reports gypsum and shallow salt deposits in many areas of western Oklahoma, and limestone karst in the Limestone Hills north of the Wichita Mountains.
What soils cause foundation problems in the Oklahoma City metro?
Much of the OKC metro has deep red shale clays like Renfrow and Kirkland that shrink and swell; other areas have shallower sandy soils over sandstone.
- OKC metro soils: What is the Oklahoma City climate like?
- USDA descriptions of the metro's main soils list mean annual precipitation of roughly 26 to 40 inches and mean annual temperatures around 56 to 64 °F.
- What ground lies under the metro?
- Clay soils formed from Permian-age shale — the Hennessey Shale and related red beds — cover large parts of the metro.
- Which soils are common in the metro?
- More series are listed in soil series in the OKC metro.
- OKC metro soils: What foundation problems are common?
- Perimeter drying settlement and tree-root desiccation settlement on the shrink-swell clays during drought; Center heave and leak-related heave when water collects under slabs on the same clays; Framing and support problems in older crawl-space homes.
- OKC metro soils: Do earthquakes affect OKC foundations?
- The Oklahoma Geological Survey lists El Reno–Mustang and central Oklahoma among the state's principal seismic areas. Telling earthquake damage from soil movement is covered in seismic damage vs soil movement and induced seismicity in Oklahoma.
- OKC metro soils: Why do so many Oklahoma City homes have foundation problems?
- Much of the metro sits on clay soils weathered from Permian shale, such as Renfrow and Kirkland, which have vertic shrink-swell properties. These clays shrink in drought and swell when wet, moving shallow foundations.
- Are soils on the east side of the metro different from the west side?
- Yes. Western and southern parts include clays over Permian shale, while other areas include Stephenville and Darnell soils formed from Permian sandstone, which are shallower to rock and not described with vertic properties.
- OKC metro soils: How much rain does the Oklahoma City area get?
- USDA soil descriptions for the area's main soils give mean annual precipitation of roughly 26 to 40 inches, with typical values of about 32 inches.
- OKC metro soils: Does the OKC area have earthquakes?
- The Oklahoma Geological Survey has identified the El Reno-Mustang area and central Oklahoma among the state's principal seismic areas.