What counts as a construction deficiency?

Texas engineering guidelines list inadequate design or construction as one of the causes of residential foundation distress, alongside soil shrink and swell, unanticipated loads, material deterioration, compressible soils, landscaping, leaking plumbing and slope instability.

What are the signs of a construction deficiency?

visible slab cracks; diagonal drywall cracks at openings; sloping floors.

How is a construction deficiency evaluated?

Because new slabs are not perfectly level, the Foundation Performance Association notes that movement cannot be determined accurately without a baseline elevation survey. See tolerances and standards and elevation surveys.

Original construction defects: How is a deficient foundation typically addressed?

Texas guidelines list underpinning, grouting, mudjacking, crack injection, tendon stressing, and partial demolition and reconstruction among slab repair methods.

Original construction defects: Can a foundation crack because it was built wrong?

Yes. Texas engineering guidelines list inadequate design or construction among the causes of residential foundation distress, alongside soil movement, unanticipated loads and material deterioration.

What construction mistakes cause concrete to crack?

Concrete industry guidance lists missing or poorly placed joints, poor subgrade preparation, high-slump concrete or added water, improper finishing and inadequate curing as common construction causes of cracking.

Original construction defects: How level is a new slab supposed to be?

The Foundation Performance Association notes that ACI 117 allows an overall levelness tolerance of 1.5 inches and that most residential slabs are built to within about 1 inch of level, which is why a baseline survey matters when judging movement.

Original construction defects: How is a deficient foundation repaired?

Texas guidelines list underpinning, grouting, mudjacking, crack injection, tendon stressing and partial demolition and reconstruction among slab repair methods. Which applies depends on what the deficiency is and how the foundation is performing.

How does a leak lift a floor?

Expansive clay swells when it gains moisture and shrinks when it loses it, and it is changes in moisture, not the clay itself, that cause movement. Leaking water or sewage pipes add water to the soil around them and can worsen swelling damage.

What Oklahoma conditions make leak heave likely?

An Oklahoma State University study using USDA soil survey data found that nearly all of Oklahoma has medium or high swelling potential, so a leak under a slab in most of the state is sitting on soil that can swell.

What are the signs of leak heave?

an interior floor hump over the leak area; floor tile cracks in a line or flooring that tents up; an unexplained high water bill.

Floor hump from slab leak: Is it heave or collapse?

The same water can do the opposite on a different soil. On expansive clay, a leak causes swelling and a hump. On loose, collapsible silt, water weakens the bonds between grains and the soil compacts, so the floor drops instead.

How is the leak found?

Meter test. Read the water meter, use no water for two hours, and read it again; a change suggests a leak; Water bills. A family of four using more than 12,000 gallons a month in winter probably has a leak; How common leaks are.

How is leak heave typically addressed?

Repair the leak. Leaks found in testing are repaired. See plumbing leak detection and repair; Monitor.

Can a leak under my slab make the floor rise?

Yes. On expansive clay, water from a leaking supply or drain line makes the soil around the leak swell, and the slab above it rises into a local hump. Leaking water and sewage pipes are a recognized source of swelling damage.

How do I check for a water leak under the slab?

The EPA describes a whole-house meter test: read the water meter, use no water for two hours, and read it again. If the reading changed, there is likely a leak. Drain lines need a separate test because they are not under constant pressure.

How common are household leaks?

The EPA estimates that leaks in an average home can waste more than 10,000 gallons a year and that about 10 percent of homes have leaks wasting 90 gallons or more per day.

Will the hump go down after the leak is fixed?

Clay that has swelled can lose moisture again after the water source is removed, which is why engineers often recommend fixing the leak and then monitoring elevations before deciding on other repairs.

How does shaking damage a house?

During an earthquake the house is shaken along with the ground, and FEMA guidance identifies brittle masonry elements as the most vulnerable parts of a home.

What earthquakes has Oklahoma had?

Oklahoma's earthquake rate rose sharply in the last decade, and the USGS links the increase to injection of large volumes of saltwater produced with oil and gas.

Earthquake shaking damage: What is the difference between magnitude and intensity?

Intensity is different from magnitude: it describes the effects of shaking at a particular place, which the USGS says makes it a more meaningful measure of severity for nonscientists.

What are the signs of earthquake damage?

Signs that appear with shaking damage include: - fresh, clean-edged cracks appearing suddenly - a chimney separating or leaning - diagonal drywall cracks at openings - vertical brick or veneer cracks

How is earthquake damage typically addressed?

FEMA advises inspecting the firebox and checking the support and anchorage of masonry veneer before chimney repair begins, and recommends lightweight metal flues in place of rebuilding a damaged chimney in its original form.

Can Oklahoma earthquakes damage a house?

Most Oklahoma earthquakes are magnitude 3 to 4, which are usually felt but rarely damaging. Larger events, such as the magnitude 5.8 Pawnee and magnitude 5.0 Cushing earthquakes in 2016, did cause damage.

What part of a house is most likely to be damaged by an earthquake?

Masonry chimneys are highly susceptible to earthquake shaking, especially older unreinforced chimneys with degraded mortar. Unreinforced brick, block and stone walls are also vulnerable.

How can I find out how strong the shaking was at my house?

The USGS publishes intensity maps for earthquakes, including Did You Feel It? maps built from public reports grouped by ZIP code. The Oklahoma Geological Survey also maintains a recent earthquakes map for the state.

Are Oklahoma earthquakes still increasing?

No. The rate of magnitude 3 and larger earthquakes peaked in 2015 and then declined. The Oklahoma Corporation Commission credits reduced wastewater injection with a drop of more than 90 percent in magnitude 3.0 earthquakes since 2015.

How does heave after tree removal happen?

Clay-rich soil shrinks as it dries and swells as it takes on water. This is called shrink-swell behavior. Heave is the upward movement of the ground, mainly in low-permeability soils like clay, as they absorb water and swell.

What controls the amount of heave?

Linear extensibility is a soil survey measure of how much a soil changes in length between moist and oven-dry; low is under 3%, moderate 3-6%, high 6-9% and very high above 9%.

What does heave after tree removal look like?

Heave lifts the part of the house nearest the old tree. Field notes associate it with stair-step brick cracks wider at the bottom, sticking doors and, where the dried zone extended under the slab, an interior floor hump.

How is heave after tree removal handled?

Because the movement is ongoing, options matched to this mechanism focus on time and moisture rather than lifting:

Can removing a tree make my foundation rise?

On shrinkable clay, yes. A large tree draws water out of the soil; once it is gone, water slowly returns, the clay swells and the ground under nearby foundations can rise. This is called heave.

How long does heave continue after a tree is cut down?

It continues until the soil moisture reaches a new balance, and published guidance says that timeframe is often hard to predict. It depends on the tree's water demand, how permeable the soil is and how much water is available.

Does every tree removal cause heave?

No. Horticultural guidance describes heave after felling as uncommon, occurring where the clay has a persistent moisture deficit created by the tree. Sandy or low-shrink soils are much less affected.

Is cutting the tree back an alternative to removing it?

Crown reduction can lessen ground movement, but published guidance says it must remove at least 70% of crown volume and be repeated about every three years. Crown thinning has been found ineffective at reducing water use.

How do tree roots cause settlement?

Clay soil shrinks as it loses water. Trees on shrinkable clay can draw moisture from soil under foundations during long dry spells; the soil contracts and the building can sink, often cracking around windows and doors.

Tree roots drying clay: How do season and drought affect it?

Texas monitoring of slabs on expansive clay found that settlement grew as the growing season progressed, droughts made it worse, and above-normal rain slowed it. Deciduous trees are less active in winter, and winter dormancy, rain and lower evaporation let slabs partly recover.

How do tree distance and species matter?

Larger trees, and trees closer to the building, carry more risk. See trees and roots.

What does tree-related settlement look like?

Damage concentrates toward the tree rather than around the whole perimeter. Field notes link it to stair-step brick cracks wider at the top, soil pulled away from the foundation, sticking doors, diagonal drywall cracks at openings and cracks that open and close seasonally.

Tree roots drying clay: What repair and moisture-control approaches are used?

Root barriers and moisture control: a Texas case history combined a root and moisture barrier with drainage improvements.

Can a tree make my foundation sink?

On shrinkable clay, yes. Tree roots draw water out of the soil, the clay shrinks, and the part of the foundation nearest the tree can settle, often with cracks around windows and doors.

How far from the house does a tree have to be?

Horticultural guidance says soil drying from high-water-demand trees can reach about the tree's height away, and for lower-demand species it is unlikely to reach beyond half the tree's height.

Tree roots drying clay: Why is the damage worse in summer?

Trees use the most water in the growing season, and drought adds to the drying. Texas monitoring found slabs settled as the summer progressed and partly recovered in winter when deciduous trees were dormant.

How deep can tree roots dry the soil?

Deeper than normal seasonal drying. In one Houston case study, tree water demand extended the active zone to about 28 feet, compared with the 4 to 8 feet usually assumed there.

Which trees use the most water?

Published UK guidance lists oak, poplar, willow and eucalyptus among high-water-demand broadleaf trees, and notes that oak accounts for the most subsidence cases in the UK.

Causes: every question answered

277 questions with short answers. Each links to the full, sourced explanation.

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.

What counts as a construction deficiency?: Texas engineering guidelines list inadequate design or construction as one of the causes of residential foundation distress, alongside soil shrink and swell, unanticipated loads, material deterioration, compressible soils, landscaping, leaking plumbing and slope instability.
What are the signs of a construction deficiency?: visible slab cracks; diagonal drywall cracks at openings; sloping floors.
How is a construction deficiency evaluated?: Because new slabs are not perfectly level, the Foundation Performance Association notes that movement cannot be determined accurately without a baseline elevation survey. See tolerances and standards and elevation surveys.
Original construction defects: How is a deficient foundation typically addressed?: Texas guidelines list underpinning, grouting, mudjacking, crack injection, tendon stressing, and partial demolition and reconstruction among slab repair methods.
Original construction defects: Can a foundation crack because it was built wrong?: Yes. Texas engineering guidelines list inadequate design or construction among the causes of residential foundation distress, alongside soil movement, unanticipated loads and material deterioration.
What construction mistakes cause concrete to crack?: Concrete industry guidance lists missing or poorly placed joints, poor subgrade preparation, high-slump concrete or added water, improper finishing and inadequate curing as common construction causes of cracking.
Original construction defects: How level is a new slab supposed to be?: The Foundation Performance Association notes that ACI 117 allows an overall levelness tolerance of 1.5 inches and that most residential slabs are built to within about 1 inch of level, which is why a baseline survey matters when judging movement.
Original construction defects: How is a deficient foundation repaired?: Texas guidelines list underpinning, grouting, mudjacking, crack injection, tendon stressing and partial demolition and reconstruction among slab repair methods. Which applies depends on what the deficiency is and how the foundation is performing.

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.

How does a leak lift a floor?: Expansive clay swells when it gains moisture and shrinks when it loses it, and it is changes in moisture, not the clay itself, that cause movement. Leaking water or sewage pipes add water to the soil around them and can worsen swelling damage.
What Oklahoma conditions make leak heave likely?: An Oklahoma State University study using USDA soil survey data found that nearly all of Oklahoma has medium or high swelling potential, so a leak under a slab in most of the state is sitting on soil that can swell.
What are the signs of leak heave?: an interior floor hump over the leak area; floor tile cracks in a line or flooring that tents up; an unexplained high water bill.
Floor hump from slab leak: Is it heave or collapse?: The same water can do the opposite on a different soil. On expansive clay, a leak causes swelling and a hump. On loose, collapsible silt, water weakens the bonds between grains and the soil compacts, so the floor drops instead.
How is the leak found?: Meter test. Read the water meter, use no water for two hours, and read it again; a change suggests a leak; Water bills. A family of four using more than 12,000 gallons a month in winter probably has a leak; How common leaks are.
How is leak heave typically addressed?: Repair the leak. Leaks found in testing are repaired. See plumbing leak detection and repair; Monitor.
Can a leak under my slab make the floor rise?: Yes. On expansive clay, water from a leaking supply or drain line makes the soil around the leak swell, and the slab above it rises into a local hump. Leaking water and sewage pipes are a recognized source of swelling damage.
How do I check for a water leak under the slab?: The EPA describes a whole-house meter test: read the water meter, use no water for two hours, and read it again. If the reading changed, there is likely a leak. Drain lines need a separate test because they are not under constant pressure.
How common are household leaks?: The EPA estimates that leaks in an average home can waste more than 10,000 gallons a year and that about 10 percent of homes have leaks wasting 90 gallons or more per day.
Will the hump go down after the leak is fixed?: Clay that has swelled can lose moisture again after the water source is removed, which is why engineers often recommend fixing the leak and then monitoring elevations before deciding on other repairs.

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.

How does shaking damage a house?: During an earthquake the house is shaken along with the ground, and FEMA guidance identifies brittle masonry elements as the most vulnerable parts of a home.
What earthquakes has Oklahoma had?: Oklahoma's earthquake rate rose sharply in the last decade, and the USGS links the increase to injection of large volumes of saltwater produced with oil and gas.
Earthquake shaking damage: What is the difference between magnitude and intensity?: Intensity is different from magnitude: it describes the effects of shaking at a particular place, which the USGS says makes it a more meaningful measure of severity for nonscientists.
What are the signs of earthquake damage?: Signs that appear with shaking damage include: - fresh, clean-edged cracks appearing suddenly - a chimney separating or leaning - diagonal drywall cracks at openings - vertical brick or veneer cracks
How is earthquake damage typically addressed?: FEMA advises inspecting the firebox and checking the support and anchorage of masonry veneer before chimney repair begins, and recommends lightweight metal flues in place of rebuilding a damaged chimney in its original form.
Can Oklahoma earthquakes damage a house?: Most Oklahoma earthquakes are magnitude 3 to 4, which are usually felt but rarely damaging. Larger events, such as the magnitude 5.8 Pawnee and magnitude 5.0 Cushing earthquakes in 2016, did cause damage.
What part of a house is most likely to be damaged by an earthquake?: Masonry chimneys are highly susceptible to earthquake shaking, especially older unreinforced chimneys with degraded mortar. Unreinforced brick, block and stone walls are also vulnerable.
How can I find out how strong the shaking was at my house?: The USGS publishes intensity maps for earthquakes, including Did You Feel It? maps built from public reports grouped by ZIP code. The Oklahoma Geological Survey also maintains a recent earthquakes map for the state.
Are Oklahoma earthquakes still increasing?: No. The rate of magnitude 3 and larger earthquakes peaked in 2015 and then declined. The Oklahoma Corporation Commission credits reduced wastewater injection with a drop of more than 90 percent in magnitude 3.0 earthquakes since 2015.

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.

How does heave after tree removal happen?: Clay-rich soil shrinks as it dries and swells as it takes on water. This is called shrink-swell behavior. Heave is the upward movement of the ground, mainly in low-permeability soils like clay, as they absorb water and swell.
What controls the amount of heave?: Linear extensibility is a soil survey measure of how much a soil changes in length between moist and oven-dry; low is under 3%, moderate 3-6%, high 6-9% and very high above 9%.
What does heave after tree removal look like?: Heave lifts the part of the house nearest the old tree. Field notes associate it with stair-step brick cracks wider at the bottom, sticking doors and, where the dried zone extended under the slab, an interior floor hump.
How is heave after tree removal handled?: Because the movement is ongoing, options matched to this mechanism focus on time and moisture rather than lifting:
Can removing a tree make my foundation rise?: On shrinkable clay, yes. A large tree draws water out of the soil; once it is gone, water slowly returns, the clay swells and the ground under nearby foundations can rise. This is called heave.
How long does heave continue after a tree is cut down?: It continues until the soil moisture reaches a new balance, and published guidance says that timeframe is often hard to predict. It depends on the tree's water demand, how permeable the soil is and how much water is available.
Does every tree removal cause heave?: No. Horticultural guidance describes heave after felling as uncommon, occurring where the clay has a persistent moisture deficit created by the tree. Sandy or low-shrink soils are much less affected.
Is cutting the tree back an alternative to removing it?: Crown reduction can lessen ground movement, but published guidance says it must remove at least 70% of crown volume and be repeated about every three years. Crown thinning has been found ineffective at reducing water use.

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.

How do tree roots cause settlement?: Clay soil shrinks as it loses water. Trees on shrinkable clay can draw moisture from soil under foundations during long dry spells; the soil contracts and the building can sink, often cracking around windows and doors.
Tree roots drying clay: How do season and drought affect it?: Texas monitoring of slabs on expansive clay found that settlement grew as the growing season progressed, droughts made it worse, and above-normal rain slowed it. Deciduous trees are less active in winter, and winter dormancy, rain and lower evaporation let slabs partly recover.
How do tree distance and species matter?: Larger trees, and trees closer to the building, carry more risk. See trees and roots.
What does tree-related settlement look like?: Damage concentrates toward the tree rather than around the whole perimeter. Field notes link it to stair-step brick cracks wider at the top, soil pulled away from the foundation, sticking doors, diagonal drywall cracks at openings and cracks that open and close seasonally.
Tree roots drying clay: What repair and moisture-control approaches are used?: Root barriers and moisture control: a Texas case history combined a root and moisture barrier with drainage improvements.
Can a tree make my foundation sink?: On shrinkable clay, yes. Tree roots draw water out of the soil, the clay shrinks, and the part of the foundation nearest the tree can settle, often with cracks around windows and doors.
How far from the house does a tree have to be?: Horticultural guidance says soil drying from high-water-demand trees can reach about the tree's height away, and for lower-demand species it is unlikely to reach beyond half the tree's height.
Tree roots drying clay: Why is the damage worse in summer?: Trees use the most water in the growing season, and drought adds to the drying. Texas monitoring found slabs settled as the summer progressed and partly recovered in winter when deciduous trees were dormant.
How deep can tree roots dry the soil?: Deeper than normal seasonal drying. In one Houston case study, tree water demand extended the active zone to about 28 feet, compared with the 4 to 8 feet usually assumed there.
Which trees use the most water?: Published UK guidance lists oak, poplar, willow and eucalyptus among high-water-demand broadleaf trees, and notes that oak accounts for the most subsidence cases in the UK.

Blasting, pile driving or heavy equipment can stress finishes and lengthen existing cracks, but most Oklahoma home cracking traces to soil movement.

What does vibration do to a house?: Ground vibration moves a house back and forth for a short time. The parts most likely to show it are brittle finishes: plaster, drywall tape joints, ceramic tile, mortar joints and brick veneer. Where a crack already exists, shaking can extend it.
What are common sources of vibration?: Quarry and construction blasting; Pile driving, vibratory compaction and demolition; Heavy truck or rail traffic close to the house.
How strong does vibration have to be to damage a house?: Ground vibration is measured as peak particle velocity, the top speed at which the ground moves as the wave passes, in inches per second. A U.S. Bureau of Mines study of homes near a large surface coal mine cited historical damage thresholds of 0.5 to 2.0 inches per second.
Vibration-related cracking: What rules limit blasting near homes?: Federal coal-mining rules cap peak particle velocity at the nearest dwelling by distance from the blast:
Vibration-related cracking: Why is soil movement the usual suspect?: Expansive clay moves a house in a slow, repeating cycle. The zone of seasonal moisture change can extend from 3 to 40 feet deep, and the soil swells when wet and shrinks when dry.
How can vibration and soil cracking be told apart?: See fresh, clean-edged cracks appearing suddenly, cracks that open and close seasonally and seismic damage vs soil movement.
How is a possible vibration claim documented?: Date-stamped photos of cracks with a scale in the frame; Seismograph readings or quarry blast logs, where they exist for the project.
How is vibration cracking usually handled?: When vibration only extended finish cracks, the matched options are cosmetic repair only and a monitoring program to confirm the cracks are not growing.
Vibration-related cracking: Can nearby construction crack my house?: Vibration can load brittle finishes such as plaster, drywall tape and brick, and it may extend cracks that already exist. Cracks from ongoing soil movement are far more common in Oklahoma, so the timing and pattern of the cracks matter.
How do I tell vibration cracks from foundation movement?: Cracks tied to a specific event tend to appear at once and have fresh, clean edges. Cracks from expansive clay usually grow over time and open and close with the seasons.
What records help show vibration was the cause?: Seismograph readings kept for blasting or construction, quarry blast logs, earthquake catalogs and dated photos of the home before and after the event help establish timing.
Vibration-related cracking: How long do Oklahoma mines and quarries keep blasting records?: Oklahoma's non-coal mining rules require a record of each blast, including seismograph readings where required, to be kept for at least three years and made available to the Department of Mines on request.
Do Oklahoma earthquakes count as vibration damage?: Earthquakes are a separate, natural or induced source of shaking. Oklahoma had about two magnitude 3.0 or larger earthquakes per year before 2009 and 903 in 2015.

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.

What happens when a crawl space stays damp?: A crawl space is the shallow open area between the ground and the wood floor of a pier-and-beam house. InterNACHI's guide to the International Residential Code (IRC) section R408 states that the main objective of the crawl space rules is moisture control.
Crawl space moisture and rot: When does wood start to decay?: Wood decay is caused by fungi, and they need four things: food (the wood itself), oxygen, a suitable temperature and enough moisture. The details:
Crawl space moisture and rot: How does wood rot affect the floor?: As decay fungi break down wood, the wood loses strength. The framing at risk in a crawl space includes the sill plate (the board resting on the foundation wall), the floor joists and the beams or girders that carry them.
What Oklahoma conditions add to crawl space moisture?: Oklahoma's climate ranges from humid subtropical in the east to semi-arid in the west. Because humid outdoor air entering vents is itself a moisture source, local humidity matters. See the Tulsa metro region page and groundwater and perched water for local conditions.
Crawl space moisture and rot: What does the building code require?: The code also calls for removing vegetation, organic material and wood forms from the crawl space, and for drainage or a raised grade where groundwater can rise within 6 inches of the floor or the space does not drain.
How is crawl space moisture typically addressed?: Remove the water. Bulk water entering the crawl space is one of the main moisture sources, which is why grading and drainage are addressed first; see drainage solutions; Control humidity.
At what moisture level does wood start to rot?: Wood decay is generally understood to occur above about 30% moisture content and not below about 20%. Air-dried wood usually stays at or below about 20%, which is why dry framing does not rot.
Why is my crawl space wet in summer when it has not rained?: Humid outdoor air entering through crawl space vents in summer can condense on cooler surfaces such as ducts, pipes and framing. That condensation adds moisture to the crawl space even without rain.
What does the building code say about crawl space ventilation?: The International Residential Code section R408 requires at least 1 square foot of vent area per 150 square feet of crawl space, reduced to 1 per 1,500 with a Class I vapor retarder on the ground, or allows unvented crawl spaces with a sealed vapor retarder and air conditioning, exhaust or dehumidification.
Crawl space moisture and rot: Can rotted floor framing be repaired?: Yes. Texas engineering guidelines for pier-and-beam homes list shimming, framing repairs, added supports and crawl space moisture control among the repair approaches.

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.

Erosion and washout voids: How does water remove soil from under a foundation?: Water that is concentrated, such as at a downspout outlet, along a low spot against the house, or at a broken pipe, can pick up soil particles and move them.
Erosion and washout voids: Which soils erode easily?: Some soils are far more erodible than others.
What are the signs of erosion voids?: an exposed slab edge or void under a footing; visible slab cracks over an unsupported area; heaved or settled flatwork such as sidewalks and patios.
How do erosion voids differ from karst sinkholes?: Karst sinkholes form when soluble bedrock such as limestone, gypsum or salt dissolves and the ground above collapses into the cavity. Erosion voids form in the soil itself, close to the surface, where water carries particles away.
How are erosion voids typically addressed?: Stop the water first. Leaks are found with testing; the EPA's meter test (read the meter, use no water for two hours, read again) checks supply lines, and Texas engineering guidelines call for testing supply and drain lines whenever a foundation will be lifted.
Erosion and washout voids: Can water wash soil out from under a slab?: Yes. Water moving through or along the soil can carry particles away and leave voids. After the heavy April 2025 rains, the Oklahoma Geological Survey expected most new sinkholes to be small and to appear where water had flowed beneath roads and driveways.
Erosion and washout voids: What is a dispersive soil?: A dispersive soil is a clay whose particles break apart and wash away easily in water, usually because sodium dominates its pore water. Small leaks through dispersive soil can enlarge into pipes or tunnels, and at least two Oklahoma flood-control dams have failed this way.
How is an erosion void different from a karst sinkhole?: An erosion void forms in the soil near the surface where runoff or leaking water carries particles away. A karst sinkhole forms when soluble bedrock such as gypsum or limestone dissolves and the material above it collapses into the cavity.
Erosion and washout voids: How do I know if a leak is washing out soil under my house?: A whole-house meter test can reveal a supply leak: read the meter, use no water for two hours and read it again. Drain lines need separate testing, which Texas engineering guidelines call for before any foundation lifting.

Is a concrete crack from shrinkage or foundation movement?

Many cracks come from materials shrinking or moving with temperature, not the foundation; a floor elevation survey and crack pattern tell them apart.

Shrinkage vs. foundation cracks: Why do materials crack on their own?: Concrete changes volume as its moisture and temperature change. As freshly placed concrete dries, it shrinks; as the seasons change, it expands and contracts. When that movement is restrained, for example by a footing, a wall or the ground, the concrete cracks.
Shrinkage vs. foundation cracks: How is concrete detailed to control cracking?: Concrete slabs are given contraction joints, grooves that create a planned weak line so the slab cracks there instead of randomly.
Shrinkage vs. foundation cracks: When is a crack more than cosmetic?: The concrete industry states that cracking is not necessarily a sign of poor materials, poor workmanship or a structural problem.
What are the signs of shrinkage or thermal cracking?: visible slab cracks, especially fine random cracks in a newer slab; nail pops and tape-joint cracks in drywall; vertical brick or veneer cracks without offset.
How are shrinkage cracks typically addressed?: Where the foundation is sound, the cracks are treated as finish repairs. Texas guidelines note that an owner may choose periodic cosmetic repairs and door adjustments rather than structural work. See cosmetic repair only.
Are hairline cracks in a new slab a foundation problem?: Not necessarily. Concrete changes volume as it dries and as temperature changes, and random early-age cracks rarely affect structural integrity or service life. Industry guidance states that cracking is not necessarily a sign of poor materials, workmanship or a structural problem.
Shrinkage vs. foundation cracks: What is crazing on concrete?: Crazing is a pattern of fine, shallow surface cracks, usually no deeper than about 1/8 inch, that form roughly hexagonal shapes. It typically appears within the first days after placement and does not affect structural integrity.
Shrinkage vs. foundation cracks: When does a basement wall crack need repair?: Typical warranties call for repair when a crack leaks, shows measurable vertical displacement or is wider than 1/8 inch. Cracks that keep widening over time call for professional evaluation.
How can I tell a shrinkage crack from a movement crack?: Shrinkage cracks tend to be fine, appear early in a building's life and do not come with changes in floor level. A floor elevation survey, especially compared with a baseline, shows whether the foundation has actually moved.

What causes center heave in an Oklahoma slab foundation?

Center heave happens when expansive clay under the middle of a slab gains moisture, often from a plumbing leak, swells and pushes the floor up.

What is center heave?: A slab-on-grade foundation is a concrete floor poured directly on the ground. These slabs are flexible enough that they tend to follow the shape of the soil beneath them as it moves.
How does center heave develop?: The slab covers the soil. Soil under a house is shielded from the weather, so its moisture can differ from soil that is exposed outside; Water reaches the soil under the center. Common sources include leaking pipes, landscape irrigation, poor drainage and groundwater.
Why are Oklahoma soils prone to center heave?: A 2017 Oklahoma State University study using USDA soil survey data found that nearly all of Oklahoma has medium or high swelling potential, and that more than 75% of the state's bedrock units are possible sources of expansive soils.
What signs often go with center heave?: Signs that commonly appear include: - an interior floor hump near the middle of the house - ceiling-wall separation at interior walls - diagonal drywall cracks at door and window openings - floor tile cracks running in a line - an unexplained high water bill when a supply leak is feeding the soil
Is it center heave or edge settlement?: Center heave and perimeter drying settlement can both leave a floor that is high in the middle. The difference is which part actually moved.
Center heave under slab: How is the water source found?: The U.S. EPA describes a simple whole-house leak check: read the water meter, use no water for two hours, and read it again; a change suggests a leak. The EPA also notes that a family of four using more than 12,000 gallons a month in winter probably has a leak.
How is center heave typically addressed?: Remove the water source. Leaks found during testing are repaired; Monitor. The Texas ASCE guidelines note that non-structural measures followed by monitoring may be prudent before, or instead of, structural repairs; Cosmetic repairs.
What is center heave in a slab foundation?: Center heave is upward movement of the middle of a slab-on-grade floor. It happens when clay soil under the covered center gains moisture over time and swells, and engineers associate it with long-term moisture gain, often in older foundations.
Center heave under slab: Can a plumbing leak cause the middle of my floor to rise?: Yes. Leaking water or sewer lines add water to the soil around them, and on expansive clay that extra water can make the soil swell. Texas engineering guidelines say supply and drain lines should be tested for leaks when lifting is part of a repair.
How can I tell center heave from the edges of the house sinking?: Both can produce a floor that is high in the middle. A single elevation survey only shows the shape at one moment; comparing repeated surveys, or a survey against reference points from original construction, shows whether the center went up or the edges went down.
Is center heave common in Oklahoma?: Oklahoma State University research found that nearly all of Oklahoma has medium or high soil swelling potential, so the expansive clay that center heave requires is widespread in the state.
Center heave under slab: How do I check for a hidden water leak?: The U.S. EPA describes a simple meter test: note the water meter reading, use no water for two hours, then read it again. A change suggests a leak somewhere in the system.

What causes sinkholes and karst subsidence in Oklahoma?

Groundwater dissolves gypsum, salt or limestone, forming cavities the soil above can sag or collapse into. Oklahoma has karst in the west, northeast and south.

How do karst sinkholes form?: Sinkholes form where groundwater moving through soluble rock dissolves it and creates underground cavities. The ground above may hold for a time, then fail when a cavity grows too large to support it.
Where is karst found in Oklahoma?: Gypsum is highly soluble and forms karst features much like limestone does; gypsum karst in the U.S. has been linked to highway subsidence, dam failure and foundation cracking.
What are the signs of karst subsidence?: a sudden depression or sinkhole in the yard or under a slab; sloping floors toward one area; stair-step cracks in brick that are wider at the top.
How does karst differ from shallow erosion voids?: Not every sinkhole is karst. The OGS notes that most of the sinkholes expected after Oklahoma's heavy April 2025 rains were small ones where water flowed beneath roads and driveways, eroding soil rather than dissolving bedrock.
How is karst evaluated?: In a 2010 study of gypsum karst risk in northwestern Oklahoma, geologists recommended gathering subsurface data from petroleum test records and core borings and surveying local landowners about past sinkholes or collapses.
What causes sinkholes in Oklahoma?: Karst sinkholes form where groundwater dissolves soluble rock such as gypsum, salt, limestone or dolomite, creating cavities that the ground above eventually settles or collapses into. Smaller sinkholes can also form when flowing water erodes soil beneath roads and driveways.
Where is gypsum karst found in Oklahoma?: Gypsum and shallow salt deposits occur in many areas of western Oklahoma. The thickest gypsum is in the southwest, mainly across about 600 square miles in Beckham, Greer and Jackson Counties, where the Blaine Formation contains up to about 150 feet of massive gypsum.
Where is limestone karst found in Oklahoma?: Limestone and dolomite karst occurs mainly in the Ozark region of northeastern Oklahoma and the Arbuckle Mountains of southern Oklahoma, with karst also noted in the Limestone Hills.
Can gypsum karst crack a foundation?: Yes. Geologists have linked gypsum karst in the United States to highway subsidence, dam failure and foundation cracking, and the Oklahoma Geological Survey notes that evaporite karst can damage or collapse homes and buildings.
Karst and sinkholes: How do I report a sinkhole in Oklahoma?: The Oklahoma Geological Survey accepts sinkhole reports through an online survey as part of its work on a statewide subsidence map.

What happens when a post-tension slab tendon is cut or fails?

That part of the slab loses the compression that helps it resist cracking from soil movement, and cutting a stressed tendon releases a dangerous force.

What is a post-tensioned slab?: A post-tensioned (PT) slab is a concrete foundation with steel cables cast inside it. Each tendon is wrapped in plastic and greased so it does not bond to the concrete.
Why is a cut tendon a hazard?: The stresses behind a stressed anchor are very high, and the engineering literature warns they can cause sudden, explosive concrete failure. Sudden loss of tension on a tendon can damage ceiling and floor finishes.
What can tendon failure look like?: The typical sign is a visible slab crack, often near where work was done or along the line of a tendon. Damage at an anchor may show as cracking or spalling at the slab edge.
How is tendon damage repaired?: Repairs are essentially the same whether the strand was cut or corroded: the damaged length is spliced so it can be stressed again.
What is a tendon in a post-tensioned slab?: A tendon is a greased, plastic-sheathed steel cable cast into the slab and stretched with a hydraulic ram after the concrete cures. A typical residential tendon is tensioned to about 33,000 pounds, which squeezes the slab together.
Can I cut or core into a post-tensioned slab during a remodel?: Tendons can be cut by other trades or during renovations, and the stresses behind a stressed anchor are high enough that sudden release can cause explosive concrete failure. Plumbing penetrations are normally planned to fit between tendons, which are typically 3 to 4 feet apart.
Can a cut or corroded tendon be repaired?: Yes. Engineering literature describes the same basic repair for cut and corroded tendons: the damaged strand is spliced with a coupler or replaced and then re-stressed, after a structural engineer reviews the slab.
What makes tendons corrode?: Tendons can corrode, especially in aggressive environments, and an anchor exposed to water or chlorides that is not properly protected is at risk. Water that gets inside the sheathing collects at low points, and wedges can corrode to the point that they can no longer grip the strand.

What is frost heave and can it lift Oklahoma porches and steps?

Frost heave happens when moist, fine-grained soil freezes and grows ice lenses that push up shallow footings, steps, porches and slabs.

How does frost heave work?: When the ground surface freezes, a freezing front moves downward through the soil.
Which soils heave?: Differences in soil, moisture and exposure from one spot to the next cause differential heave, which is what does most of the damage to roads and structures.
Frost heave: What happens when the ground thaws?: When thawing works down from the surface, meltwater can be trapped in the upper soil and weaken it.
How common is frost heave in Oklahoma?: Oklahoma's climate ranges from humid subtropical in the east to semi-arid in the west.
What are the signs of frost heave?: heaved or settled flatwork, such as sidewalks, porches and stoops that rise in winter; a horizontal crack at the brick ledge or slab edge where a shallow element meets the house.
How is frost heave typically addressed?: Reduce water. Drainage reduces the water available to form ice lenses; see drainage solutions; Use non-frost-susceptible material. Non-frost-susceptible fill helps prevent ice lens formation; Support below the frozen zone.
What causes frost heave?: Frost heave is caused mainly by ice lenses, layers of ice that grow in freezing soil as water is drawn up from unfrozen soil below. It needs freezing temperatures, available water and frost-susceptible soil all at once.
Is frost heave just water expanding when it freezes?: No. Water expands about 9 percent when it freezes, but research going back to Stephen Taber showed that the growth of ice lenses fed by water moving toward the freezing front is the main cause of heave.
Which soils heave the most in freezing weather?: Silts, loams and very fine sands, which allow water to move upward by capillary action, are the most frost-susceptible. Coarse, well-drained sands and gravels rarely heave because their pores are too large for ice lenses to form.
Does frost heave go away when the ground thaws?: Ground lifted by heave can settle back after thawing, but uplift of isolated structures by frost jacking is often permanent and can build up over several winters.

Why are my foundation piers moving after repair?

Piers that miss stable soil or rock can be lifted by swelling clay, settle when ending too shallow in shrinking clay, or be dragged down by settling fill.

What determines how well a pier performs?: For reference, Oklahoma steel push pier installation records show typical pier depths of about 8 to 16 feet, with a median of about 12 feet in Tulsa, and installation pressures around 9,000 psi with a 6,000 psi minimum. See steel push piers.
What are the signs of pier movement?: doors that bind again in a previously repaired area; stair-step brick cracks wider at the bottom; stair-step brick cracks wider at the top.
How is pier movement evaluated?: Post-repair survey. The Texas guidelines call for floor elevations to be measured after remedial work, recorded and given to the client; Repeated surveys. A single survey shows shape at one moment; repeated surveys over months or years show change.
How is pier movement typically addressed?: The approach depends on whether piers rose or settled. Recognized principles include extending supports below the zone of moisture fluctuation and designing piers in expansive soil on the assumption that their upper sections lose soil contact.
Can foundation piers move after they are installed?: Yes. Piers that end within the zone of soil that shrinks and swells can be lifted when the clay swells and lose grip when it shrinks. Engineering literature documents drilled corner piers being lifted in wet seasons and losing skin friction in the following dry season.
How deep do piers need to go to avoid soil movement?: The standard approach is to extend foundations below the zone of seasonal moisture change. In Oklahoma that active zone has been estimated at roughly 0.5 to 4 meters, and Oklahoma push pier installation records show typical depths of about 8 to 16 feet.
What is skin friction on a pier?: Skin friction is the grip of the surrounding soil along the sides of a pier. When clay dries and shrinks away from a pier, that grip is lost, and when clay swells it can grab the pier and push it upward.
How do I know if my repaired foundation is moving again?: Compare a new floor elevation survey with the survey recorded after the repair. Texas engineering guidelines call for floor elevations to be measured after remedial work and given to the client, and repeated surveys show change over time.

Why are the floors sagging over my crawl space?

Interior pads settle, wood shims crush or rot, or beams and joists are too small or span too far, so the floor sags, bounces or slopes.

Sagging crawl space floors: How is a pier-and-beam floor supported?: A pier-and-beam (crawl space) floor has three layers of support: - Joists, the closely spaced boards that the subfloor is nailed to. - Beams or girders, heavier members that carry the joists. - Interior piers or pads, posts or masonry piers on small footings that hold up the beams, often with wood or steel shims between the pier and the beam to set the height.
Sagging crawl space floors: What are the signs of interior support failure?: sagging floor between supports; bouncy or soft floors; sloping floors toward the interior.
Sagging crawl space floors: How is interior sag different from perimeter settlement?: When the perimeter foundation drops, floors slope outward toward the exterior walls. When the interior supports fail, the floor sags in the middle or between supports while the perimeter stays near level.
How is a sagging crawl space floor typically fixed?: The Texas ASCE guidelines list floor shimming, framing repairs, additional supports, restoring the open space under the floor and crawl space moisture control as pier-and-beam repair approaches.
Sagging crawl space floors: Why does my floor sag in the middle of the room?: In a pier-and-beam house, a sag between supports usually means a beam or joists are spanning too far, have been weakened by notching or decay, or an interior pier or pad under them has settled. Each of these lets the floor drop between or over the supports.
Can interior piers in a crawl space move with the soil?: Yes. Small interior pads that rest on expansive clay sit within the active zone, the depth of soil whose moisture changes with the seasons, which in Oklahoma has been estimated at roughly 0.5 to 4 meters.
Sagging crawl space floors: What moisture level lets wood framing rot?: Decay is generally understood to occur above about 30 percent moisture content and not below about 20 percent, so framing that stays damp in a crawl space is at risk.
How are sagging crawl space floors repaired?: Texas engineering guidelines for pier-and-beam foundations list floor shimming, framing repairs, added supports, restoring the open space under the floor and crawl space moisture control as repair approaches.
Sagging crawl space floors: How much floor deflection is acceptable?: Engineers often compare floor deflection to the L/360 live-load limit used in the International Residential Code, meaning a span should not bow more than 1/360 of its length.

Why do basement walls crack horizontally and bow inward?

Soil pushes sideways on basement walls, and wet backfill and swelling clay add pressure. When the push exceeds the wall's strength, it cracks, bows or slides.

What kinds of sideways pressure act on walls?: A below-grade wall carries a horizontal load from the ground beside it. That load has three parts:
How do basement and retaining walls fail?: When water-saturated soil presses against the outside of a foundation wall, the wall is pushed inward, and the inward bow opens a crack.
Bowing basement walls: What are the signs of wall pressure damage?: a horizontal crack or inward bow in a basement wall; water at the cove joint or efflorescence, the white mineral deposit left when water seeps through masonry and evaporates; a horizontal crack at the brick ledge or slab edge.
Bowing basement walls: How do pressure cracks differ from shrinkage cracks?: Not every basement wall crack comes from soil pressure. New concrete shrinks as it dries, and temperature changes make it expand and contract; when that movement is restrained, cracks form. Diagonal cracks at window, door and other opening corners usually come from shrinkage.
Bowing basement walls: How is a pushed-in wall typically fixed?: Reduce the water. The concrete industry advises finishing grade so water drains away from the foundation and installing waterproofing and drainage so water does not build up against walls. See drainage solutions; Reinforce or rebuild the wall.
What causes a horizontal crack in a basement wall?: Horizontal cracks typically form when soil outside the wall, often saturated with water, pushes the wall inward. InterNACHI describes these cracks as usually horizontal, wider than hairline and often showing signs of water intrusion.
What is hydrostatic pressure on a basement wall?: Hydrostatic pressure is the pressure of water in saturated soil pushing against a foundation wall or slab. Standing water along a foundation can push on a wall beyond the pressure it was designed for.
Are all basement wall cracks a structural problem?: No. Concrete shrinks as it dries, and diagonal cracks at window and door corners usually come from shrinkage. Typical warranties call for repair when cracks leak, show measurable displacement or are wider than 1/8 inch.
Why does clay backfill make basement wall pressure worse?: Expansive clay swells when it takes on water. In Oklahoma benchmark soils such as Bethany, Kirkland and Norge, the fine clays are dominantly montmorillonitic (smectite), a swelling clay mineral, so wet clay backfill can add swelling pressure to the normal weight of the soil.

Why do foundation edges rise after heavy rain?

When soil at the perimeter gets wetter than soil under the middle, expansive clay swells and lifts the foundation edges, leaving a dish shape.

How does edge lift happen?: Heave is soil expanding as water is added to expansive clay. Engineers describe seasonal moisture gain causing the soil to swell and push the perimeter of a slab up. Clay soils do not move if their moisture stays constant; it is changes in moisture that cause the movement.
Edge lift after rain: What happens when trees near the house are removed?: When established trees near a house are removed, the soil they had been drying can rewet. Texas engineering guidelines note that tree removal may stop shrinkage or partly restore lowered areas but can also cause upheaval, and that a waiting period may be recommended.
What Oklahoma conditions lead to edge lift?: Nearly all of Oklahoma has medium or high soil swelling potential, and OSU testing of western Oklahoma benchmark soils found their fine clays dominantly montmorillonite, a smectite clay that swells strongly when wet, most of all in the Kirkland soil.
What are the signs of edge lift?: stair-step brick cracks wider at the bottom; water ponding near the foundation; cracks that open and close seasonally.
How is edge lift told apart from look-alikes?: A single elevation survey shows shape at one moment; repeated surveys show how it is changing.
How is edge lift typically addressed?: Remove the perimeter water. Drainage changes address the source of wetting; see drainage solutions; Monitor. Texas guidelines note that non-structural measures and monitoring may be prudent before or instead of structural repairs; Limit soil swelling.
Can rain make my foundation rise?: Yes. When expansive clay at the perimeter of a house takes on water, it swells and can push the edges of the foundation up. Engineers describe seasonal moisture gain pushing the slab perimeter upward.
Why do the edges of a slab lift more easily than the middle?: The corners and edges of a uniformly loaded slab press on the soil with much less force than the center, about one-fourth as much at the corners in one engineering analysis, so swelling soil lifts them more easily.
What sends water to the edges of a house?: Common sources include landscape irrigation, poor drainage, leaking pipes, groundwater and extended wet weather. Lawn and garden watering can wet the soil outside a house while the soil under it stays drier.
Edge lift after rain: Can cutting down a tree make a foundation heave?: It can. Texas engineering guidelines note that removing trees near a foundation may restore some lowered areas but can also cause upheaval as the soil rewets, and sometimes recommend a waiting period.
Should piers be installed to stop edge lift?: Edge lift is driven by water reaching the soil, so the water source is the first thing evaluated. Texas engineering guidelines note that non-structural measures and monitoring may be prudent before or instead of structural repair.

Why do houses on Oklahoma hillsides slowly move downhill?

Clay on a slope creeps downhill a little each wet-dry season, and creeks cutting the toe remove support, pulling a house outward and down on its downhill side.

What is slope creep?: Creep is an imperceptibly slow, steady downhill movement of soil or rock. It happens when the stress on a slope is large enough to deform the soil permanently but too small to cause a sudden slide. The U.S. Geological Survey describes three kinds:
What drives slope creep?: For creek-side lots, see erosion, creeks and slopes and creeks and flood history.
What are the warning signs of slope creep?: Signs of creep include curved tree trunks, bent fences or retaining walls, tilted poles or fences, and small ripples or ridges in the soil.
How common is slope movement in Oklahoma?: The Oklahoma Geological Survey reports that most landslides occur in the eastern third of Oklahoma, where the wetter climate and steeper terrain make them more likely.
What setbacks from slopes do codes require?: Building codes based on the International Residential Code (Section R403.1.7) set two common distances:
How is slope movement repaired?: Slope movement is treated as both a slope problem and a foundation problem.
What is soil creep?: Creep is a very slow, steady downhill movement of soil or rock on a slope, too gradual to see directly. It happens when the stress on the slope is enough to deform the soil permanently but not enough to cause a sudden slide.
What are the signs of creep on a property?: The U.S. Geological Survey lists curved tree trunks, bent fences or retaining walls, tilted poles or fences, and small ripples or ridges in the soil as signs of creep.
Hillside slope creep: Where are landslides most common in Oklahoma?: The Oklahoma Geological Survey reports that most landslides occur in the eastern third of the state, where the climate is wetter and the terrain steeper.
How far should a house be from a slope?: Codes based on the International Residential Code set footings back from the top of a descending slope by one-third of the slope height, up to 40 feet, and keep buildings back from the toe of an ascending slope by half its height, up to 15 feet.

Why do Oklahoma houses settle on floodplains and soft wet clay?

Soft river alluvium and wet clay compress under a house as water squeezes out, causing gradual, largely permanent settlement, most under heavy walls.

How does soil consolidation work?: Clay and silt have tiny pores filled with water. When a load is added, the soil can only compress as that water drains out, so the process is slow. The U.S.
Where do soft soils occur in Oklahoma?: See Quaternary alluvium and terraces.
Soft soil settlement: How does flood exposure affect these sites?: FEMA's Flood Map Service Center is the official public source for flood hazard maps and can be searched by address. In Oklahoma, the Oklahoma Water Resources Board is the state coordinating agency for the National Flood Insurance Program. See creeks and flood history.
What does soft soil settlement look like?: Field notes associate soft-soil settlement with sloping floors, stair-step brick cracks wider at the top, sticking doors and, under heavy masonry, a chimney separating or leaning.
How is soft soil settlement repaired?: Repairs for this mechanism transfer the load through the soft layer to firmer soil or rock below. Options include steel push piers and helical piers.
What is soil consolidation?: Consolidation is the slow compression of fine-grained soil, such as clay or silt, as the weight on it squeezes water out of its pores. The settlement it causes is largely permanent because the collapsed pore space does not recover.
Are floodplain soils in Oklahoma soft?: Some are. The Osage soil series, mapped on eastern Oklahoma floodplains, is a thick clayey alluvium that is poorly drained, with a seasonal high water table 6 to 18 inches deep from November through May in normal years.
Soft soil settlement: How is consolidation measured?: Engineers use a laboratory consolidation test (ASTM D2435), which loads a confined, saturated soil sample in steps and measures how much and how fast it compresses.
Soft soil settlement: How do I find out if my house is in a floodplain?: FEMA's Flood Map Service Center is the official public source for flood hazard maps and can be searched by address.

Why do the edges of a house sink in dry Oklahoma weather?

Expansive clay around the outside of a house dries and shrinks while soil under the middle stays moist, so the edges sink. It is worst in drought.

How does edge drop happen?: Expansive clay shrinks as it loses moisture and swells as it gains it. Engineers describe seasonal moisture loss letting the perimeter of a slab settle, and seasonal moisture gain pushing it back up.
Edge drop in dry weather: How deep does the drying go?: The zone of soil whose moisture changes with the weather is called the active zone. - In Oklahoma, it has been estimated at roughly 0.5 to 4 meters (about 1.5 to 13 feet), depending on soil properties and climate. - A PreventionWeb hazard profile puts the zone of seasonal moisture change usually in the upper 1.5 to 2 meters, reaching about 5 meters in some cases. - Engineering literature reports seasonal fluctuation from about 3 to 40 feet deep in expansive soils, with cracks reaching deeper than often assumed and multi-year droughts drying soil deeper than previously believed.
Why do Oklahoma soils and climate cause edge drop?: Nearly all of Oklahoma has medium or high soil swelling potential, based on USDA soil survey data.
How do trees and drought affect edge drop?: Below the depth reached by surface drying, the water demand of vegetation, particularly trees on clay soils, drives the moisture changes that cause shrinking and swelling.
What are the signs of edge drop?: stair-step brick cracks wider at the top; soil pulled away from the foundation; cracks that open and close seasonally.
How is edge drop different from center heave?: Both can leave a floor high in the middle. In edge drop, the edges went down; in center heave, the center came up. Engineers associate center lift with long-term moisture gain, typically in older foundations, and edge movement with seasonal moisture changes.
How is edge drop typically fixed?: Underpinning below the active zone. A standard risk-reduction measure for shrink-swell ground is extending foundations below the zone of moisture fluctuation, adjusted for vegetation.
Edge drop in dry weather: Why does my house have more cracks in late summer?: Expansive clay around the perimeter loses moisture in hot, dry weather and shrinks, so the edges of the foundation lose support and drop. Seasonal moisture loss lets the perimeter settle, and seasonal moisture gain can push it back up, so cracks often open in dry periods and partly close after rain.
Edge drop in dry weather: Do trees cause foundation settlement?: Trees and large shrubs near a house can dry the soil beneath the foundation, especially during drought, causing the soil to shrink and the foundation to settle. Removing established trees can also cause foundation movement.
Edge drop in dry weather: How deep does soil drying reach under an Oklahoma house?: Oklahoma State University research estimated the active zone, the depth of soil whose moisture changes with the climate, at roughly 0.5 to 4 meters depending on soil and climate. Multi-year droughts can dry soil deeper than normal.
Edge drop in dry weather: How deep do foundation repair piers go in Oklahoma?: In Oklahoma steel push pier installation records, typical pier depths ranged from about 8 to 16 feet, with a median of about 12 feet in Tulsa. The goal is to bear below the soil that shrinks and swells.
Is a house that is high in the middle always settling at the edges?: No. A dome-shaped floor can also come from the center rising because of moisture build-up or a leak. Comparing elevations with reference points and repeated surveys shows which part actually moved.

Why does a chimney or column settle more than the rest of the house?

A heavy chimney, column or added story can press on the soil harder than it can support, so that spot sinks. It is a soil-strength problem, not a seasonal one.

What is concentrated load settlement?: Engineers describe three common kinds of foundation movement: heave (expansive clay swelling as it takes on water), subsidence (soil shrinking as moisture is withdrawn) and settlement, which is soil compressing because it is loaded beyond its bearing capacity.
Which parts of a house are heavy spots?: Examples of concentrated loads in a home include: - masonry chimneys and fireplaces - interior columns and posts that carry beams - second stories added after the original construction - heavy fixtures or masonry features resting on a slab
What are the signs of concentrated load settlement?: The most typical sign is a chimney separating or leaning away from the house, with a gap at the wall or roofline. Floors near a heavy column or wall may also slope toward it, showing up as sloping floors.
Heavy-spot settlement: Which Oklahoma soil conditions make it worse?: Weak, compressible soils are found in parts of Oklahoma, particularly in river-bottom alluvium (soil laid down by streams).
How is concentrated load settlement evaluated?: Load and footing. An inspection identifies what the heavy element is and, where possible, how large and deep its footing is; Soil strength.
How is concentrated load settlement typically fixed?: Underpinning, which means adding piers or piles under an existing foundation, is the usual structural approach for a settled heavy element.
What is concentrated load settlement?: It is settlement that happens under one heavy spot of a house, such as a masonry chimney, a column or an added second story, when that load presses on the soil harder than the soil can carry. The heavy area sinks relative to the lighter parts around it.
Heavy-spot settlement: Why does a chimney pull away from a house?: A masonry chimney is a heavy load concentrated on a small footing. If the soil under that footing compresses more than the soil under the rest of the house, the chimney settles or tilts and a gap opens where it meets the wall.
Heavy-spot settlement: How do engineers check whether soil can carry a load?: Common tests include the standard penetration test in a boring and laboratory unconfined compression and consolidation tests on undisturbed samples. Oklahoma transportation research has used these tests to characterize weak clayey and silty soils.
Heavy-spot settlement: Does underpinning one area fix the whole house?: No. Texas engineering guidelines note that underpinning does not improve the areas of a foundation that are not underpinned, so pier locations, sizes and depths have to be specified for the problem area.

Why does dry silty soil in Oklahoma sink when it gets wet?

Loose, dry silts hold together only while dry; when water first reaches them under a house, the bonds weaken and the soil compacts, causing sudden settlement.

What is collapsible soil?: Collapsible soils are geologically recent, loosely packed sediments that can settle or collapse suddenly. In their dry state the grains are held apart by small amounts of clay, silt and suction (the pull of thin water films between grains), and water weakens those bonds.
How does collapsible soil damage a house?: A house is built on loose, dry silt that is strong enough while dry; Water is added, usually from a human source; The bonds weaken, the soil compacts under the load, and the area over the wetted zone drops.
Where does collapsible soil occur in Oklahoma?: The Oklahoma Panhandle has tableland plains covered by loess, a wind-deposited silt. The Richfield soil series, mapped in the Panhandle, formed in calcareous loess 1 to more than 3 meters thick, with silt loam at the surface.
What are the signs of soil collapse?: stair-step brick cracks wider at the top over the wetted area; sloping floors; visible slab cracks.
Collapsible soil: How is collapse different from leak heave?: Water under a slab can make the floor go either up or down depending on the soil. On expansive clay, added water causes swelling and a hump; on collapsible silt, it causes the soil to compact and drop. See leak-induced localized heave for the clay version.
How is collapsible soil typically addressed?: Stop the water. The EPA's whole-house meter test (read the meter, use no water for two hours, read it again) checks for supply leaks, and Texas engineering guidelines call for testing supply and drain lines whenever a foundation is lifted; Monitor.
Collapsible soil: What is hydrocollapse?: Hydrocollapse, also called hydrocompaction, is sudden settlement of loose, dry soil when it gets wet. Water weakens the clay, silt and suction bonds holding the grains apart, and the grains shift into a denser arrangement, so the ground drops.
How much can collapsible soil settle?: The Colorado Geological Survey reports volume reductions of 10 to 15 percent in collapsible soils and documented settlements of more than six feet.
Where are collapsible soils found in Oklahoma?: Wind-deposited silt called loess covers tableland plains in the Oklahoma Panhandle; the Richfield soil series, for example, formed in calcareous loess 1 to more than 3 meters thick. Compacted fills elsewhere in the state can also settle when wetted.
Collapsible soil: What usually triggers collapse under a house?: Most collapse is attributed to human activity that raises soil moisture, such as lawn and shrub watering, leaking water lines in utility trenches, ponded water and blocked drainage.

Why does my ceiling crack in winter and close in summer?

Often truss uplift: roof trusses bow up in cold weather and lift the ceiling off interior walls. It mimics heave, but the floor has not moved.

What is a roof truss?: Roof trusses are factory-built triangles of lumber. The sloped top members (top chords) carry the roof, and the flat bottom member (bottom chord) doubles as the ceiling joist that the ceiling drywall is fastened to. The ends of each truss bear on the exterior walls.
How does truss uplift happen?: The two chords live in different conditions. The bottom chord is buried in ceiling insulation, where it stays warmer and drier, while the top chords are exposed to the ventilated attic air. Wood changes size with moisture, so the two parts of the truss move by different amounts.
Where does truss uplift show up?: Cracks along the ceiling-to-wall corner over interior, non-load-bearing partitions, especially walls running across the trusses; Tape torn through at the ceiling corner, rather than a crack along the edge of the tape, which may point to poor taping instead; Popping or snapping noises from the ceiling.
How can truss uplift be told from foundation heave?: Inspecting the attic framing above the crack is part of diagnosis. A floor elevation survey separates the two: truss uplift is in the roof, so the floor stays put. See ceiling-wall separation at interior walls and heave vs settlement.
How is truss uplift usually handled?: Because the truss is moving rather than failing, trade literature describes uplift as a cosmetic problem, not a structural one. Common approaches:
What is truss uplift?: Truss uplift is the seasonal upward bowing of roof trusses caused by different moisture and temperature conditions in the top and bottom members of the truss. Because the ceiling is fastened to the truss, it lifts away from interior walls.
When does truss uplift happen?: The ceiling-to-wall cracks typically open in winter and close again in summer, when the top and bottom of the truss return to similar temperature and moisture.
Is truss uplift a structural problem?: Building trade literature describes it as cosmetic rather than structural. The truss is moving with seasonal moisture, not failing.
How is truss uplift different from foundation heave?: Truss uplift happens in the roof framing, so the floor does not move. Foundation heave raises the floor and walls, which shows up on a floor elevation survey and in other signs such as sticking doors.

Why is my home addition cracking or pulling away from the house?

An addition often sits on its own foundation at a different depth or on fill, so it settles or heaves differently and the joint with the house opens up.

Why do additions move differently from the house?: An addition is a second structure attached to the first. Its foundation can differ from the original house in several ways, and any of them can make the two parts respond differently to the same soil:
What are the signs of an addition moving?: The distress usually lines up with the junction between the original house and the addition.
How is addition movement evaluated?: Separate checks. When additions have been made, the Texas guidelines say the overall foundation dimensions should be checked for each separate foundation element as well as for the whole foundation; Elevation surveys.
How is addition movement typically addressed?: Where the addition has settled, underpinning (installing piers or piles under the foundation) is the usual structural method.
Why is my addition pulling away from the house?: An addition often sits on its own foundation, which may be shallower, built at a different time, or placed on backfill. When the two foundations settle or heave by different amounts, the joint between them opens and cracks appear at that line.
Can backfill under an addition cause settlement?: Yes. Poorly placed fill is prone to settling, and Oklahoma transportation research describes compacted fill that keeps compressing after construction when its moisture content increases.
How do engineers evaluate a house with an addition?: Texas engineering guidelines say that when additions have been made, the foundation should be checked for each separate foundation element as well as for the foundation as a whole, using floor elevation surveys.
Addition separating from house: How much floor slope is considered noticeable?: A tilt of more than about 1 percent is usually noticeable, according to the Texas ASCE guidelines, and the Foundation Performance Association uses 1 percent as a tilt limit.

Why is my house rising after foundation repair done in a drought?

If piers set a house level while clay is dry and shrunken, returning rain swells the soil under unpiered areas, lifting them above the piered edges.

How does over-lift happen?: Expansive clay shrinks when it dries and swells when it wets; seasonal moisture loss lets the perimeter of a slab settle, and seasonal moisture gain pushes it back up. Clay does not move if its moisture stays constant, but moisture rarely stays constant.
Over-lift after drought repair: Why does dry-season timing matter?: The depth and degree of drying set the stage for later swelling: - In Oklahoma, the active zone, the depth of soil whose moisture changes with the climate, has been estimated at roughly 0.5 to 4 meters (about 1.5 to 13 feet), with shallow soil responding most strongly to weather. - Engineering literature reports seasonal moisture fluctuation in expansive soils ranging from about 3 to 40 feet deep, and multi-year droughts show the zone can be deeper than previously believed. - Expansive soils are most damaging where climates have pronounced wet and dry seasons, with shrink-swell cycles repeating each year.
What are the signs of over-lift?: an interior floor hump that was not there before the repair; doors that bind or show tapered gaps; ceiling-wall separation at interior walls.
How is over-lift evaluated?: Texas guidelines say floor elevations should be measured after remedial work and given to the client, and that a single survey shows shape at one moment while repeated surveys show change over time.
How is over-lift typically addressed?: Monitor first. The Texas guidelines note that non-structural measures and monitoring may be prudent before or instead of further structural repair. See monitoring program; Re-set adjustable supports.
Why did my floors get worse after foundation repair?: If the house was lifted while the clay was dry, the soil under unpiered areas, especially the interior, can swell when rain returns. The piered perimeter is held in place while the interior rises, so new humps, binding doors and cracks can appear.
Over-lift after drought repair: Does underpinning control the whole slab?: No. Texas engineering guidelines note that underpinning does not improve areas that are not underpinned and that its performance can be affected by soil moisture changes.
Over-lift after drought repair: How deep does seasonal moisture change go?: Oklahoma State University research estimated the active zone in Oklahoma at roughly 0.5 to 4 meters, and engineering literature reports seasonal moisture change in expansive soils from about 3 feet to as much as 40 feet in extreme cases, deeper in multi-year droughts.
Over-lift after drought repair: Can a house be leveled perfectly?: Texas engineering guidelines state that lifting is governed by field judgment to limit damage and that it is unlikely an elevation adjustment will produce a level foundation.
How can I find out how dry the soil was when my house was lifted?: The Oklahoma Mesonet's statewide network of about 120 stations records soil moisture and weather, so records from a nearby station can show conditions around the date of the lift.

Why is my house settling on fill dirt in Oklahoma?

Loose fill, or fill with debris or organic matter, slowly compresses under a house. Wetting speeds it up, and it is worst where the fill is deepest.

What is fill and why does it settle?: Fill is soil placed by people rather than left where nature deposited it. Builders use it to level sloping lots, raise building pads, and fill ravines, ditches and old ponds.
Where is fill settlement common in Oklahoma?: ODOT research has also characterized compressible clayey and silty alluvial soils in Oklahoma river systems at sites where settlement of fill was a known problem.
What are the signs of fill settlement?: stair-step brick cracks wider at the top, on the side over the fill; sloping floors that fall toward the fill side; diagonal drywall cracks at doors and windows.
How is fill settlement different from look-alikes?: Collapse and consolidation of fill reduce the soil's volume, so the movement is downward and does not reverse when the soil dries. Expansive clay behaves differently, shrinking and swelling as its moisture changes; compare perimeter drying settlement.
How is fill settlement evaluated?: History. Texas engineering guidelines list cut-and-fill observations among the items in a detailed foundation report; Elevation surveys. Repeated surveys over months or years show whether the settlement is continuing; Soil testing.
How is fill settlement typically fixed?: Underpinning with piers or piles that pass through the fill to firmer native soil or rock is the common structural approach.
Why would a house built on fill keep settling?: Fill that was placed loose, poorly compacted or mixed with debris keeps compressing under the weight of the house and its own weight. Oklahoma transportation research found that compacted fill can also settle after construction when its moisture content increases.
Does fill settlement go up and down with the seasons?: Fill consolidation is a one-way process: the fill compresses and does not spring back. That is different from expansive clay, which shrinks and swells as it dries and wets.
How can I find out if my house is on fill?: Clues come from lot history and soil sampling: old aerial photos and maps, builder or grading records, and soil borings or hand-auger samples that show mixed soil colors, debris or organic material.
How is settlement on fill repaired?: The usual structural approach is underpinning with piers or piles that pass through the fill to firmer native soil or rock below. Texas engineering guidelines note that underpinning must be specified by location, size and depth and does not improve areas that are not underpinned.