Oklahoma data: every question answered
137 questions with short answers. Each links to the full, sourced explanation.
Does chemical soil stabilization work on Oklahoma clay?
Oklahoma highway research found lime cuts swelling in ordinary clay but can cause severe heave in high-sulfate soil; two acid additives did not cut swelling.
- Why does this research matter to homeowners?
- Chemical soil stabilization means mixing or injecting a material into clay to reduce its tendency to swell and shrink.
- Chemical stabilization research: What did lime, fly ash and kiln dust tests show?
- A University of Oklahoma study (FHWA-OK-08-10) measured three-dimensional swell after curing for three Oklahoma soils.
- Chemical stabilization research: Do acid-based additives work?
- A 2013 University of Oklahoma study for ODOT (FHWA-OK-13-06) tested two commercial acid-based liquid additives, described as sulfonated oil products mixed with acid, on three Oklahoma clays: Lela clay (Kay County), Renfrow clay (Logan County) and Vernon soil.
- What are the limits of the research?
- These studies tested road subgrade mixing and lab samples, not injection beneath existing houses; Results vary by soil; a treatment that works on low-sulfate Kingfisher soil behaved very differently on Vernon soil; Measured soil properties for many Oklahoma soils are listed in soil lab values.
- Chemical stabilization research: Does lime reduce swelling in Oklahoma clay?
- On low-sulfate soil it can. In Oklahoma research on Kingfisher soil, 3% lime cut swelling by about 95%, and 9% lime produced slight shrinkage instead of swell.
- Chemical stabilization research: Can lime make clay swell more?
- Yes, in sulfate-rich soil. Vernon soil from western Oklahoma, with 15,400 ppm sulfate, swelled 1,237% more after 3% lime was added, because the lime and sulfate formed the expansive mineral ettringite.
- Chemical stabilization research: Do acid-based soil stabilizer products work on Oklahoma clay?
- A 2013 University of Oklahoma study for the state DOT tested two acid-based additives on three Oklahoma clays and found no substantial strength gain, little change in plasticity and no reduction in swelling potential.
- Chemical stabilization research: Has sulfate heave happened on an Oklahoma project?
- Yes. In 2004, several miles of State Highway 412 near Woodward failed when lime-treated soil from a gypsum-rich borrow source heaved as ettringite formed.
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 active are earthquakes in Oklahoma?
- In a 2008 summary, an Oklahoma Geological Survey geologist described four main seismic areas in the state: El Reno-Mustang, central Oklahoma, Love and Carter counties, and the Arkoma Basin. Typical magnitudes were 1.8 to 2.5, with focal depths generally under 3 miles.
- What did Oklahoma's larger earthquakes actually damage?
- The magnitude 5.6 earthquake of November 2011, centered in Lincoln County about 45 miles east of Oklahoma City, buckled several roads including Highway 62, and chimneys collapsed through the roofs of some homes.
- What did the 2015 Insurance Department bulletin say?
- In March 2015 the Oklahoma Insurance Commissioner issued Earthquake Insurance Bulletin No. PC 2015-02. Its main points:
- How often have Oklahoma earthquake claims been paid?
- Separate earthquake coverage also became more common: about 10 to 15 percent of Oklahomans had it in 2016, up from about 2 percent in 2011, according to the Insurance Department.
- Earthquake insurance claims: How have Oklahoma courts treated "earth movement" exclusions?
- An earth movement exclusion is policy wording that removes coverage for damage caused by the ground shifting, settling or heaving. Oklahoma cases show the outcome can turn on exact policy wording and the cause of the movement:
- What does this mean for foundation-related claims?
- Because insurers are expected to know a home's condition before coverage starts, records of that condition carry weight in a claim. Useful records include dated photos of brick, drywall and slab cracks, and an elevation survey showing how level the floors were.
- How many Oklahoma earthquake claims were paid in 2014?
- The Oklahoma Insurance Commissioner reported about 100 earthquake claims filed in 2014, with only eight paid.
- Can an insurer deny an earthquake claim as pre-existing damage?
- A 2015 Oklahoma Insurance Department bulletin said that if an insurer denies a claim for pre-existing damage, the Commissioner expects it to have inspected the property before coverage began and kept current records of its condition.
- Do Oklahoma earthquake policies cover brick veneer and chimneys?
- Not always. The Insurance Department bulletin refers to the common exclusion of coverage for masonry veneer walls and chimneys, so policy wording should be checked.
- Can an insurer deny a claim by saying the earthquake was man-made?
- The 2015 bulletin told insurers not to deny claims based on an unsupported belief that quakes were caused by fracking or injection wells.
- How many earthquake claims were paid after the 2016 Pawnee earthquake?
- By early November 2016, 274 damage claims had been filed and four had been paid, totaling $24,232, according to figures reported from the Oklahoma Insurance Department.
- Earthquake insurance claims: Does an earth movement exclusion apply when a broken pipe causes clay to swell?
- Oklahoma rulings have gone both ways depending on policy wording. A 2009 federal appeals ruling on an Edmond home enforced the exclusion, while the Oklahoma Supreme Court in 2019 found a policy's exclusion ambiguous for a pipe rupture because it listed only natural events.
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.
- What is the active zone?
- Clay soil swells as it takes on water and shrinks as it dries. Near the surface, rain, heat and plants change soil moisture all year. Deeper down, moisture stays nearly constant.
- How deep is the active zone in Oklahoma?
- An Oklahoma State University study combined field measurements from the Oklahoma Mesonet and the U.S. Department of Energy's Atmospheric Radiation Measurement network with modeling. Its findings:
- Active zone depth: How do cracks carry drying deeper?
- When clay shrinks it cracks, and open cracks let air and heat reach soil far below the surface. NRCS Official Series Descriptions record this for Oklahoma-area clays:
- Active zone depth: What do Mesonet drought records show?
- D-levels come from the U.S. Drought Monitor: D2 is severe, D3 extreme and D4 exceptional drought. For year-by-year history, see drought and wet years, and for how to read live soil moisture, see Mesonet for foundation pros.
- How do pier depths compare to the active zone?
- Oklahoma steel push pier installation records show piers in Tulsa typically reaching 8 to 16 feet, with a median of about 12 feet. That is deeper than most of the 1.6 to 13 foot active zone range estimated for the state.
- What is the active zone in Oklahoma soil?
- The active zone is the upper layer of soil whose moisture, and therefore volume, changes with the seasons. An Oklahoma State University study estimated it at roughly 0.5 to 4 meters (about 1.6 to 13 feet) depending on soil and climate.
- Active zone depth: How deep did soil dry out in the 2022 Oklahoma drought?
- The Oklahoma Mesonet measured critically dry soils down to at least 32 inches in September 2022, when about 64% of the state was in extreme or exceptional drought.
- Why do cracks matter for drying depth?
- Open shrinkage cracks let air and heat reach deeper soil. NRCS descriptions of some Oklahoma clay soils record cracks more than 30 inches deep during dry periods.
- Do piers in Tulsa go below the active zone?
- Oklahoma installation records show steel push piers in Tulsa typically reaching 8 to 16 feet, with a median of about 12 feet, which is deeper than most of the estimated active zone range.
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.
- Depth to rock, Tulsa and OKC: What do these boring numbers mean?
- A boring is a test hole drilled by a geotechnical engineer to log soil and rock. These reports separate two depths:
- What do Tulsa metro borings show?
- Nine borings for a sewer project found weathered rock at 1 to 8 feet and competent shale or limestone at 4 to 14.5 feet.
- Depth to rock, Tulsa and OKC: What do Oklahoma City metro borings show?
- The Hennessey unit is red clay shale and mudstone. Depth to bedrock varied widely across three structures:
- Depth to rock, Tulsa and OKC: What do the summary statistics show?
- Calculated from the borings above (drilled borings that reached rock, each counted once):
- How do rock depths compare with pier depths?
- Oklahoma steel push pier installation records show typical pier depths of 8 to 16 feet, with a median of about 12 feet in Tulsa. That sits close to the Tulsa boring medians above.
- Depth to rock, Tulsa and OKC: What are the limits of this data?
- Highway and sewer borings are often on low ground, cuts or fill, so a hilltop lot may be shallower; Reports sometimes conflict between their summary tables and boring logs; the original PDF is the authority; Rock depth can change sharply over short distances, as the Bridge C borings show.
- How deep is rock under Tulsa?
- In public drilled borings on upland shale in Tulsa reviewed here, competent rock was found at a median of about 14 feet, with most between about 9.5 and 14.5 feet. Two borings for one retaining wall went 30 and 35 feet without reaching rock.
- How deep is rock in Oklahoma City?
- It varies with the bedrock unit. Borings in Hennessey shale at the I-35/I-240 interchange hit bedrock between 2 and 41 feet, while borings in Garber sandstone at I-35 and Waterloo Road reached competent rock at 20.5 to 95 feet.
- How deep do steel push piers go in Tulsa?
- Oklahoma installation records show typical pier depths of about 8 to 16 feet, with a median near 12 feet in Tulsa, which is close to the depth of weathered and competent shale in nearby borings.
- Why do borings close together show different rock depths?
- Bedrock surfaces are uneven, and alluvium (creek-deposited soil) fills old channels. One Oklahoma City bridge site had bedrock at 17.5 feet in one boring and 41 feet in another.
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.
- Why does depth to rock matter?
- Rock depth controls how deep foundation piers may go and whether they end on rock or on friction in dense soil. Bedrock here means shale, sandstone or limestone below the soil. "Weathered" rock has partly broken down; "competent" rock is hard enough that drilling stalls.
- Depth to rock from borings: What do Tulsa city reports show?
- Strength is reported as unconfined compressive strength (UCS), the pressure a rock core takes before it crushes.
- What do borings show in central Oklahoma?
- A state maintenance and residency facility study reported competent shale (standard penetration test refusal) at 15.5 to 25 feet. Above the rock were lean to fat clays, with plasticity index up to 41, that the report classified as expansive, over very weathered shale.
- What do borings show about groundwater?
- Three east Tulsa borings had water at 7 to 9.5 feet at the end of drilling, and groundwater was not observed in four of the nine borings; The 91st St creek-side borings had water at 13.5 to 15 feet; the upland borings were dry; Water perched on top of rock is common; see groundwater and perched water.
- Is bedrock shallow in Tulsa?
- On many upland sites it is. City of Tulsa reports show shale as shallow as 15 to 23 inches below pavement in one east Tulsa neighborhood and competent rock within 4 to 14.5 feet at borings for two east Tulsa utility projects.
- Why is rock deeper near the Arkansas River?
- River and creek deposits fill in over the shale. Along the Arkansas River in Tulsa County, shale is generally about 5 to 10 feet below the river bottom but 20 to 30 feet below the banks.
- Depth to rock from borings: How strong is Tulsa-area shale?
- It varies a lot. Rock cores from an east Tulsa sewer project tested at 4,880 to 9,560 psi, while shale along the Arkansas River averaged only 565 to 737 psi.
- How deep is rock south of Oklahoma City in McClain County?
- At a state facility near I-35 and SH-59, borings reached competent shale at 15.5 to 25 feet under expansive clay and very weathered shale.
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.
- Oklahoma foundation code history: Why does a home's construction date matter?
- The rules in force when a house was built shape what is under it: how its footings were reinforced, how the frame was bolted down, and whether later trenching near the foundation was restricted. Older homes predate these amendments.
- What are Oklahoma's 2018 IRC foundation amendments?
- The Oklahoma Uniform Building Code Commission adopted the 2018 IRC by permanent rule effective September 14, 2022. Its Chapter 4 (Foundations) amendments include:
- When did Oklahoma homes move from crawl spaces to slabs?
- Slab-on-grade houses were still uncommon in Tulsa in the mid-1950s.
- Have any Oklahoma cities set stricter local rules?
- After the May 20, 2013 tornado, Moore became the first U.S. city to adopt building rules aimed specifically at limiting tornado damage. New homes there must be built to resist winds up to 135 mph, compared with the 90 mph nationally accepted standard cited at the time.
- Oklahoma foundation code history: What rules apply to manufactured homes?
- Manufactured homes follow a separate set of rules. New homes in Oklahoma must be installed to HUD's federal installation standards (24 CFR Part 3285) or the manufacturer's approved instructions by a state-licensed installer.
- What soils does the code have to deal with?
- Code footings sit on Oklahoma soils that can be highly expansive. A 1978 Oklahoma Agricultural Experiment Station study described Kirkland soil, sampled in Canadian County, as very plastic and highly expansive, which restricts its use for most engineering purposes.
- When did Oklahoma adopt the 2018 IRC foundation amendments?
- Oklahoma's permanent rule adopting the 2018 International Residential Code with state amendments took effect September 14, 2022.
- Does Oklahoma require rebar in house footings?
- Yes. The state amendment to IRC section R403.1 adds two No. 4 reinforcing bars to all footings and requires No. 4 ties at cold joints between footings and foundation walls.
- Oklahoma foundation code history: Can a plumber or pool installer dig next to my footing?
- Oklahoma's added section R403.1.9 says trenching parallel to footings may not extend into the footing's bearing plane, defined by a 45-degree line down from the outside bottom edge of the footing. It names plumbing, electrical, storm shelters and pools.
- What frost depth does Oklahoma use for footings?
- The state rule leaves the frost depth entry blank for each local building authority to fill in, so the required depth depends on the city or county.
- What share of new Oklahoma homes are built on slabs?
- In 2024, 97.9% of new single-family homes in the census division that includes Oklahoma, Texas, Arkansas and Louisiana were built on slabs, compared with 73% nationally, according to NAHB analysis of Census data.
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.
- What is the Thornthwaite Moisture Index?
- The TMI compares a location's yearly precipitation with its potential evapotranspiration, the amount of water that would evaporate from soil and pass through plants if water were always available.
- Moisture index by city: How does Oklahoma's climate change from east to west?
- No verified city-by-city TMI table was found for this page. The ODOT-sponsored study instead mapped TMI statewide with three calculation methods and found that the zero TMI line runs across central Oklahoma, so the climate there ranges from moist sub-humid to dry sub-humid.
- Moisture index by city: What does this mean for each region?
- Tulsa and northeast Oklahoma sit at the wetter, lower-evaporation end of the state. See Tulsa metro; Oklahoma City lies in central Oklahoma, near the zero TMI line between moist and dry sub-humid climates.
- What is the Thornthwaite Moisture Index?
- It is a climate number that compares how much rain an area gets with how much water the climate could evaporate and plants could use. Positive values mean a wetter climate and negative values a drier one.
- Moisture index by city: Is western Oklahoma drier than eastern Oklahoma for foundations?
- Yes. OSU Extension reports May to October evaporation of about 28 to 30 inches in eastern Oklahoma versus about 40 to 44 inches in the southwest, west-central and Panhandle divisions.
- Why do engineers care about the moisture index?
- Slab design methods for expansive clay use a climate moisture index to estimate how deep and how far in from the slab edge soil moisture will change. Drier climates generally mean deeper seasonal drying.
- Is there an official Oklahoma table of moisture index by city?
- This site did not find a published city-by-city table it could verify. A 2014 ODOT-sponsored study published statewide TMI contour maps instead, and values used in design are usually read from such maps or calculated for the site.
- What is the moisture index in central Oklahoma?
- A 2014 ODOT-sponsored study found the zero TMI line runs across central Oklahoma, so the climate there ranges from moist sub-humid to dry sub-humid.
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.
- OKC trees and planting distance: How much tree canopy does the OKC metro have?
- The Association of Central Oklahoma Governments (ACOG) commissioned a canopy assessment of the Oklahoma City metropolitan area in 2019.
- What are the official planting distances?
- The City of Oklahoma City's planting guide sets these distances:
- OKC trees and planting distance: Where do tree roots grow?
- The dripline is the outer edge of a tree's canopy. Because roots reach far past it, a tree that looks well clear of the house can still draw water from soil along the foundation, a process described in tree-root desiccation settlement.
- OKC trees and planting distance: What species traits does OSU Extension list?
- OSU Extension's selection guide lists these traits for trees common in Oklahoma yards:
- Why do trees matter on Oklahoma clay?
- Clay soils across central and eastern Oklahoma swell and shrink with moisture (see shrink-swell and active zone). A tree concentrated near one side of a house adds uneven drying on that side, and removing a large tree can lead to post-tree-removal heave as the soil rewets.
- What are the most common trees in the Oklahoma City metro?
- A 2019 regional canopy assessment found eastern redcedar (13.2%), slippery elm (9.7%) and western soapberry (9.6%) were the most common species.
- OKC trees and planting distance: How much of the OKC metro is covered by tree canopy?
- The 2019 assessment of a 536-square-mile study area measured 22.4% tree canopy, with an estimated 65 million trees of 74 species.
- OKC trees and planting distance: How close to a house can I plant a large tree in Oklahoma City?
- The city's planting guide says medium and large trees should be planted no closer than 30 feet to buildings or structures.
- OKC trees and planting distance: How deep are most tree roots?
- OSU Extension says most trees grow a fibrous root system in the upper 24 inches of soil, and roots can spread up to three to five times the canopy width.
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.
- Who sets the installation rules?
- Manufactured home installation in Oklahoma falls under Title 765, Chapter 37 of the Oklahoma Administrative Code, administered by the Oklahoma Used Motor Vehicle, Dismantler, and Manufactured Housing Commission.
- What are the support rules for used homes (OAC 765:37-7-3)?
- A footing is the pad that spreads a pier's load onto the soil.
- What are the anchoring rules for used homes (OAC 765:37-7-4)?
- Anchors and ties hold the home down and resist sideways movement in wind.
- Why do surface piers move on Oklahoma clay?
- The rules above place block footings on firm undisturbed soil or compacted fill after organic material is removed. Where that soil is expansive clay, it swells when wet and shrinks when dry.
- Who regulates manufactured home installation in Oklahoma?
- The Oklahoma Used Motor Vehicle, Dismantler, and Manufactured Housing Commission licenses installers. Installing a home with an unlicensed installer is listed as an unacceptable procedure under Oklahoma Administrative Code 765:37.
- How far apart can piers be under a used manufactured home in Oklahoma?
- Piers under each main frame beam can be no more than 6 feet on center, and the end piers must be within 2 feet of the frame ends.
- What soil strength does Oklahoma assume for manufactured home footings?
- The rule assumes at least 1,500 pounds per square foot unless site conditions call for a lower value, in which case an engineer, architect or geologist should be consulted. Soil testing can change the assumed value.
- How much shimming is allowed under a manufactured home?
- Shims must be nominal 4x6x1 pieces used in pairs and driven tight, taking up no more than one inch of height.
- How many anchor ties does a used manufactured home need?
- Diagonal ties may be no more than 11 feet apart along each side, with the end ties within 2 feet of each end. Each anchor must resist 4,725 pounds total with a working capacity of 3,150 pounds.
What do lab tests show about Oklahoma clay soils?
Oklahoma subsoil clays mostly test with plasticity index in the high 20s to low 40s, and some western soils carry very high sulfate that affects lime treatment.
- Oklahoma soil lab values: What do the key lab terms mean?
- Liquid limit (LL): the water content at which clay starts to flow like a liquid. Higher LL usually means more clay activity; Plasticity index (PI): the range of water content over which the soil stays moldable.
- What do statewide soil tests show?
- An Oklahoma Geological Survey geologist reported that over 75% of Oklahoma has bedrock units that can produce expansive soils, and that montmorillonite clay can swell to roughly 1.5 to 2 times its dry volume when wet.
- What do soil tests show in central Oklahoma?
- The swell is in the subsoil. Kirkland's surface layer tested at PI 4, while its subsoil tested at PI 30 to 32. The study described Kirkland as an "inherently unstable soil" because of its high, montmorillonite-dominated clay content; Shrink-swell is measurable.
- What do soil tests show in the Tulsa area?
- City of Tulsa boring reports provide measured values on weathered shale ground:
- What do soil tests show in southern and western Oklahoma?
- Durant (south-central): the NRCS series description says upper subsoil horizons are 40 to 60% clay and that cracks more than 1 cm wide and 30 inches deep form during dry periods.
- What is a typical plasticity index for Oklahoma clay?
- Measured subsoil values in central Oklahoma commonly fall around 27 to 41. For example, Kirkland subsoil in Canadian County tested at PI 30 to 32 and Renfrow clay in Logan County at about 33 before curing.
- Is Oklahoma shale itself expansive?
- Not always. The U.S. Geological Survey found that the main clay minerals in Hennessey shale cored at Lake Hefner were illite and kaolinite, which have low shrink-swell potential. The soils formed on top of such rock can be far more expansive.
- How much of Oklahoma has expansive soil?
- The Oklahoma Geological Survey reported that over 75% of Oklahoma has bedrock units that can produce expansive soils.
- Why does sulfate in soil matter?
- When lime or similar calcium-based treatment is added to sulfate-rich soil, an expansive mineral called ettringite can form. In one Oklahoma test, 3% lime increased the swell of a high-sulfate soil by 1,237%.
What must Oklahoma home inspectors report about foundations?
Oklahoma inspectors must inspect the foundation, describe signs of movement and recommend correction, evaluation or monitoring, but need not find the cause.
- Who regulates home inspectors in Oklahoma?
- Home inspection in Oklahoma is regulated under Title 158, Chapter 70 of the Oklahoma Administrative Code.
- What must inspectors check?
- Under OAC 158:70-1-3, the structural part of a home inspection covers:
- What are inspectors not required to do?
- The same standard lists limits on the inspection:
- What must Oklahoma sellers disclose about foundations?
- The Residential Property Condition Disclosure Act applies to homes with one or two dwelling units.
- What time limits apply to foundation and construction claims?
- A statute of repose is an outer deadline that runs from completion of the work, regardless of when damage is discovered.
- Inspector foundation duties: What consumer protections apply to in-home sales?
- Cancellation: The federal Cooling-Off Rule gives buyers until midnight of the third business day to cancel many sales made at their home, and the seller must explain this right and provide cancellation forms at the time of sale; Deceptive practices: Oklahoma's Consumer Protection Act lists unlawful practices, including falsely claiming that services or repairs are needed.
- Inspector foundation duties: Who licenses contractors, and are permits needed?
- The Construction Industries Board regulates plumbers, electricians, mechanical tradespeople, home inspectors, building inspectors and roofing. General contracting and foundation repair are not on that list.
- Inspector foundation duties: What happens after the inspection?
- Home inspectors identify signs of movement but are not required to determine causes or perform engineering services.
- Does an Oklahoma home inspector have to report foundation problems?
- Yes. Oklahoma's standards require inspectors to inspect the foundation and describe indicators of foundation or structural movement, and to recommend correction, further evaluation or monitoring of reported conditions.
- Will a home inspector tell me what caused the foundation movement?
- Not necessarily. The Oklahoma standards say inspectors are not required to determine the causes of any condition or defect, or the methods or materials for repair.
- Does a home inspector have to go into the crawl space?
- Inspectors must enter the crawl space or state how it was observed, but entry is not required if headroom is under 18 inches, the access opening is smaller than 18 by 24 inches, or the space is excessively wet or hazardous.
- Who licenses home inspectors in Oklahoma?
- The Construction Industries Board. No one may perform or advertise home inspection work without a valid license from the Board unless legally exempt.
- How long does an Oklahoma buyer have to sue over an undisclosed foundation defect?
- Under the Residential Property Condition Disclosure Act, a purchaser's action must be brought within two years after the date of transfer, and the remedy is actual damages such as repair costs.
- Inspector foundation duties: Is there a time limit on construction defect claims in Oklahoma?
- Yes. Oklahoma's statute of repose bars tort claims over design or construction deficiencies in an improvement to real property brought more than ten years after substantial completion.
What were Oklahoma's worst recent drought and wet years?
Oklahoma had near-statewide drought in 2011 and 2012, its wettest month on record in May 2015, and a 2022 drought that dried soils at least 32 inches deep.
- Drought and wet years: Why does weather history matter for foundations?
- Oklahoma's expansive clays shrink as they dry and swell as they wet. The upper layer that responds to weather, called the active zone, is estimated at about 0.5 to 4 meters (1.6 to 13 feet) deep across the state, and the shallowest soil responds most strongly to climate.
- What were Oklahoma's historic drought and wet periods?
- The U.S. Geological Survey identifies four major 20th-century drought periods in Oklahoma by water year: 1929 to 1941, 1952 to 1956, 1961 to 1972 and 1976 to 1981.
- Drought and wet years: What were the recent weather extremes?
- Drought levels come from the U.S. Drought Monitor: D2 is severe, D3 extreme, and D4 exceptional.
- Drought and wet years: How much water does Oklahoma lose to evaporation?
- Evaporation pulls water out of exposed soil and water surfaces during the warm season. OSU Extension fact sheet BAE-1529 reports average May to October evaporation from shallow water bodies:
- Drought and wet years: What was the wettest month in Oklahoma history?
- May 2015, when the statewide average was 14.40 inches, beating the old record of 10.75 inches from October 1941. Oklahoma City received 19.48 inches that month.
- How bad was the 2011 to 2012 drought in Oklahoma?
- In August 2011, 93% of Oklahoma was in extreme or exceptional drought, including 65% in exceptional drought. In August 2012, about 97% of the state was in extreme or exceptional drought.
- How dry was the soil in the 2022 drought?
- The Oklahoma Mesonet measured critically dry soils down to at least 32 inches in September 2022, when about 94% of the state was in severe drought or worse.
- Drought and wet years: Does Oklahoma lose more water to evaporation than it gets in rain?
- Evaporation is high. OSU Extension reports May to October evaporation from shallow water of about 28 to 30 inches in eastern Oklahoma and about 40 to 44 inches in the southwest, west central and Panhandle divisions.
- What was Oklahoma's worst drought on record?
- The 1950s drought stands out: 1950 to 1956 was the driest seven-year period of the 20th century, averaging 28.51 inches of rain a year statewide, and it ended with major flooding in May 1957.
- Drought and wet years: What was Oklahoma's wettest year?
- 2015, with a preliminary statewide total of 53.88 inches, breaking the 1957 record of 47.88 inches.
Why does Tulsa's flood history matter for Oklahoma foundations?
Tulsa's floods, peaking in 1984 on Mingo Creek, led to buyouts and floodplain rules. Creek corridors hold deep, soft deposits and shallow water.
- What were Tulsa's major floods?
- The City of Tulsa's flooding history lists these events:
- What about flooding in Oklahoma City?
- Flooding is a statewide hazard; an Oklahoma Geological Survey summary lists floods among Oklahoma's six main natural hazards. Heavy rain also hits central Oklahoma: in May 2015 Oklahoma City received 19.48 inches, its wettest month on record.
- Tulsa creeks and flood history: Why do creek corridors matter for foundations?
- Creeks and rivers lay down alluvium, loose sediment of clay, silt and sand. Along the Arkansas River in Tulsa County, shale lies about 5 to 10 feet below the river bottom but generally 20 to 30 feet below the banks.
- What was the worst flood in Tulsa history?
- The Memorial Day flood of 1984, when about 15 inches of rain fell overnight. It killed 14 people, injured 288 and damaged or destroyed nearly 7,000 buildings, mostly along Mingo Creek.
- Which Tulsa creeks have flooded most often?
- City records list repeated floods on Mingo, Joe, Haikey, Fry, Bird and Flat Rock creeks, with Mingo Creek flooding at least twice in 1974; for some residents that was a third flood in a year.
- When did Tulsa adopt floodplain regulations?
- Tulsa adopted a 100-year flood standard in 1971 and comprehensive floodplain regulations in 1977. A stormwater utility fee was created by ordinance in 1986.
- Is the soil different near creeks?
- Often, yes. Along the Arkansas River in Tulsa County, shale is about 5 to 10 feet below the river bottom but generally 20 to 30 feet below the banks, with soil and river deposits filling the space above.