Visible slab cracks: What does this sign look like?

Cracks show in the exposed concrete of a garage, porch or patio, or telegraph through floor coverings as cracked tile or a ridge under carpet. They may be hairline, open, or offset with one edge higher than the other.

Why do concrete slabs crack?

Concrete shrinks as it cures and dries, by about 0.0002 to 0.0008 inch per inch. Over a 20-foot slab, that works out to roughly 0.05 to 0.19 inch of shortening, which is why slabs crack even when nothing is wrong with the soil.

How is a slab crack read?

Engineering guidance notes that most concrete cracks do not compromise structural integrity, so their physical characteristics are evaluated rather than their presence alone.

Visible slab cracks: How is it documented?

Width and offset at several points along the crack; Change over time with a crack monitor; cyclical movement may take six months or more to measure; Floor elevation survey, the engineering step beyond a visual first impression. See elevation surveys.

Are cracks in a concrete slab normal?

Many are. Concrete shrinks as it dries, and engineering guidance notes that most slab cracks do not compromise structural integrity. Their physical characteristics, such as offset, pattern and whether they are growing, are what get evaluated.

What does it mean if one side of a slab crack is higher than the other?

An offset means the concrete on one side has moved up or down relative to the other. That points to soil movement, settlement or heave under the slab rather than simple drying shrinkage.

Can slab cracks be repaired by injection?

Engineering repair guidance describes epoxy injection for cracks of about 1/32 inch and wider. Injection restores the crack but does not address soil movement that caused it.

Are post-tensioned slabs different?

Yes. Post-tensioned slabs contain steel tendons stretched tight after the concrete hardens to hold the slab in compression. Design guidance calls for a minimum residual average prestress of 100 psi and continuous post-tensioned beams.

What do nail pops and tape cracks look like?

Nail pops: small circles or bumps over fasteners, often in rows along a stud or ceiling joist; Tape-joint cracks: straight, thin cracks that follow the seams between drywall sheets, often at ceiling lines or inside corners.

Nail pops and tape cracks: Why do they happen?

Lumber loses moisture after a house is built and as heating and cooling dry the air. Brick industry data put wood shrinkage at about 0.0025 inch per inch for each 1 percent change in moisture content, which works out to roughly 1 percent shrinkage for every 4 percent drop.

Nail pops and tape cracks: How are they documented?

Map where the pops and cracks are on a floor plan and compare that pattern with a floor elevation survey. Engineering guidance treats a relative elevation survey as the step beyond a visual first impression.

Do nail pops mean my foundation is moving?

Usually not on their own. A federal housing guide lists nail pops and visible seams among reported wallboard problems, and wood framing shrinks as it dries, which can push fasteners and joints. They point toward foundation movement only when they come with other signs such as sloping floors or diagonal cracks at openings.

Nail pops and tape cracks: How much does wood framing shrink?

Brick industry data put wood shrinkage at about 0.25 percent of dimension for each 1 percent drop in moisture content, or roughly 1 percent for every 4 percent drop.

What drywall cracks are linked to foundation movement?

Engineering guidance lists cracking of gypsum board walls and ceilings, separation of walls from ceilings, and racked door and window frames as distress indicators, usually read together with a floor elevation survey.

Sticking windows, cracked glass: What does this sign look like?

A sash that rubs, binds or needs force to open or close; A lock or latch that no longer lines up with its keeper; An uneven gap between the sash and the frame, wider at one corner than the other.

Why does foundation movement show up at windows?

The InterNACHI Standards of Practice require home inspectors to report signs of possible foundation movement, and name cracked drywall, cracked brick, out-of-square door frames and floors that are not level as examples.

Sticking windows, cracked glass: What moves foundations in Oklahoma clay?

The trade word for soil that grows when wet and shrinks when dry is expansive clay (also called shrink-swell clay).

Sticking windows, cracked glass: How is it documented?

Each affected window: wall, floor level, which side binds, and the date; Whether the same window changes between wet and dry months, since clay moisture follows the seasons; Nearby signs: diagonal drywall cracks at openings, brick separating from the window frame, floor slope.

Can sticking windows mean I have a foundation problem?

They can. InterNACHI's inspection standards list out-of-square door frames among signs of possible foundation movement, and its foundation guidance lists sticking doors or windows among settlement signs, but one sticking window on its own does not prove the foundation moved.

Why do my windows stick in late summer but work fine in spring?

Expansive clay shrinks as it dries and swells as it wets, so foundations on clay can move with the seasons. Openings that change with the seasons fit that pattern, which is why the season of each observation is recorded.

Does cracked window glass mean the foundation moved?

Not by itself. Cracked glass is recorded together with drywall cracks, brick cracks and floor slope, and the overall pattern plus an elevation survey is used to decide whether foundation movement is involved.

Sticking windows, cracked glass: Will a home inspector tell me if the foundation is failing?

A home inspector reports signs of possible foundation movement. Inspection standards say inspectors are not required to judge the adequacy of structural systems or provide engineering services.

Unexplained high water bill: What does this sign look like?

Monthly use rises and stays high, or spikes, without new people, a pool, or a change in watering. EPA suggests comparing month-to-month use on the bill to spot spikes. This is relevant to slab-on-grade, post-tensioned and crawl space houses.

Unexplained high water bill: How common are household leaks?

EPA estimates that household leaks waste nearly 1 trillion gallons of water a year nationwide, and that an average household's leaks can waste more than 9,300 gallons a year. About 9 percent of homes have leaks that waste 50 gallons or more per day.

Unexplained high water bill: How do you check for a leak?

If the meter moves and no fixture or irrigation leak is found, the leak may be in a buried line or under the slab. See plumbing leak detection and repair.

Unexplained high water bill: Why does an under-slab leak matter for the foundation?

Expansive clay swells when it gains water. Broken water or sewer pipes add moisture that can worsen swelling damage to nearby structures. Foundation design guidance names leaking utility lines as a source of water that can wet the soil and cause foundation heave.

How can I tell if I have a hidden water leak?

EPA's meter test is to pick a two-hour period when no water is used and read the meter before and after. If the reading changes, there is probably a leak.

How much water use is too much in winter?

EPA guidance says a family of four using more than 12,000 gallons per month in a cold month such as January or February probably has a serious leak.

Unexplained high water bill: Can a leak under my slab damage the foundation?

Yes. Water from leaking supply or sewer lines wets the soil under the slab, and on expansive clay that can cause swelling and heave. Engineering guidance names leaking utility lines as a cause of foundation heave.

Unexplained high water bill: What leaks are most common in homes?

EPA points to worn toilet flappers, dripping faucets, leaking showerheads and irrigation system damage as common household leaks, along with hidden leaks at water heaters and appliance supply lines.

Slow drains and sewer backups: What does this sign look like?

Several fixtures drain slowly, toilets gurgle, or sewage backs up into a low tub or floor drain. On its own this does not point to the foundation. It becomes a foundation question when it shows up with floor cracks, a hump in the floor, or an unexplained rise in the water bill.

Slow drains and sewer backups: How do soil movement and drain lines interact?

Expansive clay swells when it gets wetter and shrinks as it dries. The depth where this seasonal moisture change happens is often called the active zone. Shallow plastic pipes that sit in this zone of seasonal moisture change are exposed to large stresses from shrinking soil.

Slow drains and sewer backups: How is it documented?

Engineering repair guidance calls for testing water supply and sanitary drain lines for leaks when jacking or lifting is part of the work, and for repairing leaks that are found; gas lines may also need adjustment.

Slow drains and sewer backups: What order should the work follow?

Repair guidance for expansive-soil foundations puts correcting moisture sources, including plumbing leaks and drainage, first, with leveling after. Insurance treatment of leaks and resulting damage in Oklahoma is covered in plumbing leaks and insurance.

Can foundation movement break my sewer line?

Shallow plastic pipes that run through the zone of seasonal soil moisture change are exposed to large stresses from shrinking and swelling clay. Movement of the soil and slab around them is one way drain lines can be damaged.

Can a broken sewer line cause foundation problems?

Yes. Water from broken water or sewer pipes adds moisture to the soil, which can make expansive clay swell and worsen damage to nearby structures. Engineering guidance lists leaking utility lines as a cause of foundation heave.

Should drains be tested before a foundation is lifted?

Engineering repair guidance calls for testing water supply and sanitary drain lines for leaks when jacking or lifting is part of the work, and for repairing any leaks found.

Doors binding, tapered gaps: What does this sign look like?

A door that rubs the frame at the top or on the latch side, or needs force to close; A latch or deadbolt that no longer lines up with the strike plate; A gap above the door (at the head, the top piece of the frame) that is wider at one end than the other.

Why does foundation movement show up at doors?

A door frame is a rectangle set into the wall framing. When one part of a foundation moves more than another, the framing above it is pulled out of square.

Doors binding, tapered gaps: How does Oklahoma clay move a house?

Expansive clay (also called shrink-swell clay) swells when it gets wetter and shrinks when it dries.

Doors binding, tapered gaps: How do you read the pattern?

Other mechanisms in this library, such as fill consolidation settlement, pier movement after repair and interior support failure in crawl spaces, are covered on their own pages.

Doors binding, tapered gaps: How is it documented?

Each affected door: wall, floor level, where it rubs, and which end of the head gap is wider; The date of each observation, since the ASCE homeowner guide advises monitoring existing cracks for progressive or seasonal movement; Nearby signs: diagonal drywall cracks at openings, sticking windows, sloping floors.

Doors binding, tapered gaps: Can a sticking door mean my foundation is moving?

It can. Home inspection standards list out-of-square door frames among indications of possible foundation movement, and civil engineering guidance lists poor door alignment as an indication of movement. One sticking door on its own does not prove the foundation moved.

Doors binding, tapered gaps: Why is the gap at the top of my door wider on one side?

When a foundation moves unevenly, the wall framing around the door is pushed out of square, a condition engineers call racking. The door then sits at an angle in its frame, so the gap above it tapers from one side to the other.

Why do my doors stick in some seasons but not others?

Expansive clay swells when wet and shrinks when dry, and that moisture cycle repeats year after year. Openings that change with the seasons fit that pattern, which is why the season is recorded with each observation.

Warning signs: every question answered

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

Are cracks in a garage or house slab a foundation problem?

Most are concrete shrinkage and not structural; a crack matters when one side is higher, it keeps widening, or it lines up with signs like sloping floors.

Visible slab cracks: What does this sign look like?: Cracks show in the exposed concrete of a garage, porch or patio, or telegraph through floor coverings as cracked tile or a ridge under carpet. They may be hairline, open, or offset with one edge higher than the other.
Why do concrete slabs crack?: Concrete shrinks as it cures and dries, by about 0.0002 to 0.0008 inch per inch. Over a 20-foot slab, that works out to roughly 0.05 to 0.19 inch of shortening, which is why slabs crack even when nothing is wrong with the soil.
How is a slab crack read?: Engineering guidance notes that most concrete cracks do not compromise structural integrity, so their physical characteristics are evaluated rather than their presence alone.
Visible slab cracks: How is it documented?: Width and offset at several points along the crack; Change over time with a crack monitor; cyclical movement may take six months or more to measure; Floor elevation survey, the engineering step beyond a visual first impression. See elevation surveys.
Are cracks in a concrete slab normal?: Many are. Concrete shrinks as it dries, and engineering guidance notes that most slab cracks do not compromise structural integrity. Their physical characteristics, such as offset, pattern and whether they are growing, are what get evaluated.
What does it mean if one side of a slab crack is higher than the other?: An offset means the concrete on one side has moved up or down relative to the other. That points to soil movement, settlement or heave under the slab rather than simple drying shrinkage.
Can slab cracks be repaired by injection?: Engineering repair guidance describes epoxy injection for cracks of about 1/32 inch and wider. Injection restores the crack but does not address soil movement that caused it.
Are post-tensioned slabs different?: Yes. Post-tensioned slabs contain steel tendons stretched tight after the concrete hardens to hold the slab in compression. Design guidance calls for a minimum residual average prestress of 100 psi and continuous post-tensioned beams.

Are drywall nail pops and tape joint cracks a foundation problem?

Usually not. They are most often caused by wood framing drying and shrinking, and point to the foundation only when other signs line up.

What do nail pops and tape cracks look like?: Nail pops: small circles or bumps over fasteners, often in rows along a stud or ceiling joist; Tape-joint cracks: straight, thin cracks that follow the seams between drywall sheets, often at ceiling lines or inside corners.
Nail pops and tape cracks: Why do they happen?: Lumber loses moisture after a house is built and as heating and cooling dry the air. Brick industry data put wood shrinkage at about 0.0025 inch per inch for each 1 percent change in moisture content, which works out to roughly 1 percent shrinkage for every 4 percent drop.
Nail pops and tape cracks: How are they documented?: Map where the pops and cracks are on a floor plan and compare that pattern with a floor elevation survey. Engineering guidance treats a relative elevation survey as the step beyond a visual first impression.
Do nail pops mean my foundation is moving?: Usually not on their own. A federal housing guide lists nail pops and visible seams among reported wallboard problems, and wood framing shrinks as it dries, which can push fasteners and joints. They point toward foundation movement only when they come with other signs such as sloping floors or diagonal cracks at openings.
Nail pops and tape cracks: How much does wood framing shrink?: Brick industry data put wood shrinkage at about 0.25 percent of dimension for each 1 percent drop in moisture content, or roughly 1 percent for every 4 percent drop.
What drywall cracks are linked to foundation movement?: Engineering guidance lists cracking of gypsum board walls and ceilings, separation of walls from ceilings, and racked door and window frames as distress indicators, usually read together with a floor elevation survey.

Are sticking windows or cracked glass a foundation sign?

They are possible signs of foundation movement but do not identify a cause alone. The whole-house pattern and an elevation survey separate it from other causes.

Sticking windows, cracked glass: What does this sign look like?: A sash that rubs, binds or needs force to open or close; A lock or latch that no longer lines up with its keeper; An uneven gap between the sash and the frame, wider at one corner than the other.
Why does foundation movement show up at windows?: The InterNACHI Standards of Practice require home inspectors to report signs of possible foundation movement, and name cracked drywall, cracked brick, out-of-square door frames and floors that are not level as examples.
Sticking windows, cracked glass: What moves foundations in Oklahoma clay?: The trade word for soil that grows when wet and shrinks when dry is expansive clay (also called shrink-swell clay).
Sticking windows, cracked glass: How is it documented?: Each affected window: wall, floor level, which side binds, and the date; Whether the same window changes between wet and dry months, since clay moisture follows the seasons; Nearby signs: diagonal drywall cracks at openings, brick separating from the window frame, floor slope.
Can sticking windows mean I have a foundation problem?: They can. InterNACHI's inspection standards list out-of-square door frames among signs of possible foundation movement, and its foundation guidance lists sticking doors or windows among settlement signs, but one sticking window on its own does not prove the foundation moved.
Why do my windows stick in late summer but work fine in spring?: Expansive clay shrinks as it dries and swells as it wets, so foundations on clay can move with the seasons. Openings that change with the seasons fit that pattern, which is why the season of each observation is recorded.
Does cracked window glass mean the foundation moved?: Not by itself. Cracked glass is recorded together with drywall cracks, brick cracks and floor slope, and the overall pattern plus an elevation survey is used to decide whether foundation movement is involved.
Sticking windows, cracked glass: Will a home inspector tell me if the foundation is failing?: A home inspector reports signs of possible foundation movement. Inspection standards say inspectors are not required to judge the adequacy of structural systems or provide engineering services.

Can a high water bill mean a leak affecting my foundation?

A rising bill with no change in use usually means a leak. A leak under a slab can wet expansive clay and push part of the floor up.

Unexplained high water bill: What does this sign look like?: Monthly use rises and stays high, or spikes, without new people, a pool, or a change in watering. EPA suggests comparing month-to-month use on the bill to spot spikes. This is relevant to slab-on-grade, post-tensioned and crawl space houses.
Unexplained high water bill: How common are household leaks?: EPA estimates that household leaks waste nearly 1 trillion gallons of water a year nationwide, and that an average household's leaks can waste more than 9,300 gallons a year. About 9 percent of homes have leaks that waste 50 gallons or more per day.
Unexplained high water bill: How do you check for a leak?: If the meter moves and no fixture or irrigation leak is found, the leak may be in a buried line or under the slab. See plumbing leak detection and repair.
Unexplained high water bill: Why does an under-slab leak matter for the foundation?: Expansive clay swells when it gains water. Broken water or sewer pipes add moisture that can worsen swelling damage to nearby structures. Foundation design guidance names leaking utility lines as a source of water that can wet the soil and cause foundation heave.
How can I tell if I have a hidden water leak?: EPA's meter test is to pick a two-hour period when no water is used and read the meter before and after. If the reading changes, there is probably a leak.
How much water use is too much in winter?: EPA guidance says a family of four using more than 12,000 gallons per month in a cold month such as January or February probably has a serious leak.
Unexplained high water bill: Can a leak under my slab damage the foundation?: Yes. Water from leaking supply or sewer lines wets the soil under the slab, and on expansive clay that can cause swelling and heave. Engineering guidance names leaking utility lines as a cause of foundation heave.
Unexplained high water bill: What leaks are most common in homes?: EPA points to worn toilet flappers, dripping faucets, leaking showerheads and irrigation system damage as common household leaks, along with hidden leaks at water heaters and appliance supply lines.

Can slow drains or sewer backups signal foundation movement?

On expansive clay, soil movement can break buried drain pipes and a leaking drain can make the slab heave, so the two are often checked together.

Slow drains and sewer backups: What does this sign look like?: Several fixtures drain slowly, toilets gurgle, or sewage backs up into a low tub or floor drain. On its own this does not point to the foundation. It becomes a foundation question when it shows up with floor cracks, a hump in the floor, or an unexplained rise in the water bill.
Slow drains and sewer backups: How do soil movement and drain lines interact?: Expansive clay swells when it gets wetter and shrinks as it dries. The depth where this seasonal moisture change happens is often called the active zone. Shallow plastic pipes that sit in this zone of seasonal moisture change are exposed to large stresses from shrinking soil.
Slow drains and sewer backups: How is it documented?: Engineering repair guidance calls for testing water supply and sanitary drain lines for leaks when jacking or lifting is part of the work, and for repairing leaks that are found; gas lines may also need adjustment.
Slow drains and sewer backups: What order should the work follow?: Repair guidance for expansive-soil foundations puts correcting moisture sources, including plumbing leaks and drainage, first, with leveling after. Insurance treatment of leaks and resulting damage in Oklahoma is covered in plumbing leaks and insurance.
Can foundation movement break my sewer line?: Shallow plastic pipes that run through the zone of seasonal soil moisture change are exposed to large stresses from shrinking and swelling clay. Movement of the soil and slab around them is one way drain lines can be damaged.
Can a broken sewer line cause foundation problems?: Yes. Water from broken water or sewer pipes adds moisture to the soil, which can make expansive clay swell and worsen damage to nearby structures. Engineering guidance lists leaking utility lines as a cause of foundation heave.
Should drains be tested before a foundation is lifted?: Engineering repair guidance calls for testing water supply and sanitary drain lines for leaks when jacking or lifting is part of the work, and for repairing any leaks found.

Do sticking doors or tapered door gaps mean foundation movement?

They can. Out-of-square door frames are a listed sign of possible foundation movement, but the pattern across the house and a floor survey decide the cause.

Doors binding, tapered gaps: What does this sign look like?: A door that rubs the frame at the top or on the latch side, or needs force to close; A latch or deadbolt that no longer lines up with the strike plate; A gap above the door (at the head, the top piece of the frame) that is wider at one end than the other.
Why does foundation movement show up at doors?: A door frame is a rectangle set into the wall framing. When one part of a foundation moves more than another, the framing above it is pulled out of square.
Doors binding, tapered gaps: How does Oklahoma clay move a house?: Expansive clay (also called shrink-swell clay) swells when it gets wetter and shrinks when it dries.
Doors binding, tapered gaps: How do you read the pattern?: Other mechanisms in this library, such as fill consolidation settlement, pier movement after repair and interior support failure in crawl spaces, are covered on their own pages.
Doors binding, tapered gaps: How is it documented?: Each affected door: wall, floor level, where it rubs, and which end of the head gap is wider; The date of each observation, since the ASCE homeowner guide advises monitoring existing cracks for progressive or seasonal movement; Nearby signs: diagonal drywall cracks at openings, sticking windows, sloping floors.
Doors binding, tapered gaps: Can a sticking door mean my foundation is moving?: It can. Home inspection standards list out-of-square door frames among indications of possible foundation movement, and civil engineering guidance lists poor door alignment as an indication of movement. One sticking door on its own does not prove the foundation moved.
Doors binding, tapered gaps: Why is the gap at the top of my door wider on one side?: When a foundation moves unevenly, the wall framing around the door is pushed out of square, a condition engineers call racking. The door then sits at an angle in its frame, so the gap above it tapers from one side to the other.
Why do my doors stick in some seasons but not others?: Expansive clay swells when wet and shrinks when dry, and that moisture cycle repeats year after year. Openings that change with the seasons fit that pattern, which is why the season is recorded with each observation.
Doors binding, tapered gaps: Does a home inspector decide whether the foundation has failed?: No. Inspection standards require inspectors to report possible foundation movement but say they are not required to report on the adequacy of any structural system or to provide engineering services.

Is a vertical crack in brick veneer a foundation problem?

A vertical crack near a corner, offset or long wall is often brick expansion. Tapered cracks, or ones at an addition, more likely involve the foundation.

What does a vertical brick crack look like?: The crack runs straight up and down, through brick units or along the vertical (head) joints, with roughly the same width from top to bottom. It is common near outside corners, at offsets in the wall, and partway along long uninterrupted walls.
Why does brick crack vertically?: Fired clay brick absorbs moisture from the air and expands permanently; most of that growth happens in the first weeks after firing, with a slower rate for years. Brick is the only common building material listed with this kind of irreversible moisture expansion.
When does a vertical crack point to the foundation?: Settlement and deflection cracks have a tapering shape. Nearly vertical settlement cracks are described at the joints of bay windows, porches and additions; see differential movement at additions. For tapered patterns, see stair-step crack wider at top.
How is a vertical crack documented?: Width along the length. Measure at the top, middle and bottom. Even width supports expansion; taper supports movement; Activity. A clean crack suggests recent movement, while a dirty or previously filled crack may be inactive; Location.
Is a vertical crack in my brick a foundation problem?: Often it is not. Clay brick expands permanently with moisture and moves with temperature, and long walls without enough expansion joints can crack. Vertical cracking at corners can also come from thermal movement, while settlement cracks usually taper.
How much does a brick wall grow?: Brick industry guidance estimates total unrestrained movement for brick veneer at about 0.0009 times the wall length, combining permanent moisture expansion and temperature movement. That is roughly a quarter inch over 25 feet.
Where should brick expansion joints be?: Brick industry guidance places vertical expansion joints near corners, preferably within about 2 feet, and at offsets, with spacing of no more than 25 feet on walls without openings and about 20 feet on walls with several openings.
What makes a vertical crack look like settlement instead?: Settlement and deflection cracks taper, wide at one end and hairline at the other. A vertical crack that is clearly wider at the top or bottom, or that sits where an addition or porch meets the house, points more toward foundation movement.

What causes a hump in the middle of a slab floor?

Usually heave: soil under the area swells and pushes the slab up, from slow moisture build-up, a plumbing leak or removal of a large tree on expansive clay.

What does a floor hump look like?: The floor rises toward a point or area away from the outside walls, so the perimeter sits lower than the middle. Interior doors may rub at the top, and tile or wood flooring over the high spot may crack. This sign applies to slab-on-grade and post-tensioned houses.
Why do slab floors hump?: Expansive clay swells when it gains water and shrinks when it loses it, and most of Oklahoma has these soils. Soil only moves when its moisture changes unevenly across the site, and leaking pipes, poor drainage, irrigation and trees are listed contributors.
Interior floor hump: How is it documented?: Elevation survey. A relative floor elevation survey, drawn as a map, is the step engineering guidance uses beyond a visual first impression. A hump shows as a high zone with lower readings toward the perimeter. See elevation surveys; Short-distance caution.
Interior floor hump: Why does the cause matter for repair?: Repair guidance for expansive soils puts correcting the moisture source, such as plumbing leaks and drainage, ahead of leveling, and notes that leveling measures mainly mitigate distress.
Why is there a hump in the middle of my floor?: On expansive clay, a raised interior area usually means the soil under that part of the slab has gained moisture and swollen. Long-term moisture build-up under the slab, a plumbing leak, and the removal of a large tree are described causes.
Can a plumbing leak raise my floor?: Yes. Engineering guidance lists leaking utility lines as a source of water that can wet the soil and cause foundation heave, and broken water or sewer pipes are described as making swelling damage worse.
Can cutting down a tree near the house make the floor rise?: It can. Soil near trees removed shortly before construction may be drier and subject to localized heave, and removing a tree can cause heave as the soil re-wets, especially for trees that were there before the house was built.
How do I confirm a hump is real and not just uneven construction?: A relative floor elevation survey is the standard tool. Engineering guidance cautions that over short distances, under about 20 feet, built-in unevenness from construction can dominate the readings.

What causes a sudden sinkhole or depression near an Oklahoma house?

It can be a sinkhole over dissolving gypsum or limestone, found in parts of western, northeastern and southern Oklahoma, or a washout where water removed soil.

Sinkhole or sudden depression: What does this sign look like?: A circular or bowl-shaped low spot appears in the yard, under a driveway or next to the foundation, sometimes over days and sometimes overnight. Nearby slabs may crack or drop. Any foundation type can be affected, including slab-on-grade, crawl space and flatwork.
What is a sinkhole?: A sinkhole is an area of ground with no natural surface drainage, so rainwater collects in it and drains underground. Sinkholes range from a few feet to hundreds of acres across.
Where do sinkholes occur in Oklahoma?: Gypsum and anhydrite lie within about 30 meters of the surface across roughly 4 percent of Oklahoma, including the Permian Blaine gypsum of western Oklahoma. Gypsum karst can develop fast enough, on a human time scale, to threaten highways and other structures.
Sinkhole or sudden depression: What are washouts and other human causes?: Not every depression is karst. Human activities linked to sinkholes include groundwater pumping, construction, and changes to natural drainage, as well as leaking pipes beneath roads and buildings.
Sinkhole or sudden depression: How is it investigated?: Probing and drilling locate soft zones and voids directly; Geophysics. Researchers in western Oklahoma combined electrical resistivity, electromagnetic and seismic methods to map solution cavities in gypsum; Reporting.
Does Oklahoma have sinkholes?: Yes. Limestone and dolomite karst occurs mainly in the Ozark area of northeast Oklahoma and the Arbuckle Mountains, and gypsum and salt karst occurs in many parts of western Oklahoma. The Oklahoma Geological Survey maps sinkholes and asks residents to report them.
Can a sinkhole form quickly?: Yes. Sinkholes can develop slowly or within hours or days. Gypsum karst can form on a human time scale, fast enough to pose a collapse hazard to roads and buildings.
Can a leaking pipe cause a sinkhole?: Water moving underground, including from leaking pipes and mains, can carry soil away and leave voids. Leaking pipes beneath roads and buildings are listed as a human cause of sinkholes.
Sinkhole or sudden depression: How are voids under the ground found?: Probing and drilling locate voids directly. Geophysical methods such as electrical resistivity and seismic surveys have been used in western Oklahoma to map cavities in gypsum without drilling every spot.

What causes sloping floors in an Oklahoma house?

Causes range from a drying slab edge to settling interior piers; slopes over about 1 percent are usually noticeable, and an elevation survey finds the cause.

Sloping floors: What does this sign look like?: Floors run downhill toward one wall or corner, doors swing open or shut on their own, and furniture or cabinets sit out of level.
Sloping floors: How much slope is noticeable?: Engineering guidance gives these reference points:
What causes sloping floors?: Other listed mechanisms, such as fill consolidation and soft soil consolidation, are covered in the causes section of this library.
How are sloping floors measured?: Elevation survey. A relative floor elevation survey, with readings drawn on a floor plan, is the level of evaluation engineering guidance uses beyond a first impression. See elevation surveys; Short-distance caution.
Sloping floors: How much floor slope is too much?: Engineering guidance notes that a floor slope greater than 1 percent is usually noticeable, and the Americans with Disabilities Act treats a 2 percent slope as too large. Whether slope is structurally significant is judged with an elevation survey and visible distress together.
What causes floors to slope in a house?: Common causes include the soil under the outside edge drying and shrinking, trees drawing moisture from the soil, settlement where additions or porches meet the house, soft or poorly compacted soil, sinkholes in soluble rock areas, and settling interior piers in crawl space homes.
Is a sloping floor always a foundation problem?: No. Original construction leaves some built-in unevenness, and over short distances, under about 20 feet, that unevenness can dominate floor readings. A survey across the whole house shows whether there is a consistent pattern of movement.
How are sloping floors measured?: With a relative floor elevation survey, which records the height of the floor at many points and draws them on a plan. Engineering guidance treats this survey as the step beyond a visual first impression.

What do diagonal drywall cracks at door corners mean?

Diagonal cracks from door and window corners are a common sign of uneven foundation movement, since corners concentrate stress.

Why do cracks start at openings?: A wall with a door or window is weakest at the corners of the opening, where the solid wall meets the gap. When one part of the foundation moves up or down relative to another, the wall is pulled out of square, and that distortion concentrates at those corners.
Diagonal drywall cracks: What does the crack direction tell you?: In foundation diagnosis, the working rule is that a diagonal crack tends to run toward the relatively low side of the wall. A crack that rises from a door corner toward an outside wall suggests the outer side dropped (edge settlement) or the interior rose (center heave).
What causes can produce these cracks?: Less often, interior support failure in crawl spaces or an original construction deficiency is the cause.
How do you document these cracks?: Note which corner the crack starts at and which way it runs; Measure the widest point and mark the crack ends with pencil and date; Photograph with a ruler or crack gauge in view.
Diagonal drywall cracks: What are the next steps?: Use the distress pattern library to compare crack maps and the symptom matrix to weigh mechanisms.
What causes diagonal cracks above doors and windows?: The corners of openings are the weakest points in a wall, so when the wall is distorted by uneven foundation movement, cracks start there and run at an angle. Settlement from drying clay, heave from swelling clay, fill settlement, slope movement and earthquakes can all produce them.
Which way does a diagonal crack point?: As a working rule in foundation diagnosis, the crack tends to run toward the side that has moved down relative to the rest of the wall. Plotting crack directions on a floor elevation survey shows whether they agree with the measured low areas.
Are hairline drywall cracks a foundation problem?: Not always; drywall can crack for reasons unrelated to the foundation. Cracks that grow, cluster around openings, come with out-of-square door frames or uneven floors, or follow the seasons are more likely to reflect foundation movement.
How much movement causes visible cracks?: UK guidance on clay soils notes that cracks usually need about 5 to 10 millimeters of movement before they appear, often around windows and doors.

What does a gap at the frieze board above brick mean?

A gap between the top of the brick and the frieze board often means the foundation edge carrying the brick has dropped, commonly as perimeter clay dries.

Frieze board or trim gap: How does the gap form?: On a brick home, the brick veneer is a single layer of brick standing on the outer ledge of the foundation, while the roof, soffit and frieze board are attached to the wood framing. The frieze board covers the joint where the top of the brick meets the framing.
Frieze board or trim gap: What is edge drop?: This site links the sign to perimeter drying settlement (edge drop). Expansive clay shrinks as it dries.
Frieze board or trim gap: What signs usually come with it?: Stair-step brick cracks wider at the top on the same wall; Brick separating from window or door frames; Soil pulled away from the foundation in dry weather.
Frieze board or trim gap: When might it not be the foundation?: A gap at trim does not always come from the foundation. Signs pointing away from the foundation include a gap that is even along a whole wall, no cracking in the brick below, and no matching interior signs.
Frieze board or trim gap: How do you document it?: Measure the gap at evenly spaced points along each wall, and at every corner; Photograph each point with a ruler in view; Note which corner has the widest gap and check the brick below it for cracks.
Frieze board or trim gap: What are the next steps?: Compare with the distress pattern library and the symptom matrix.
What is a frieze board?: A frieze board is the trim board that runs along the top of an exterior wall, just under the eaves. On brick homes it often covers the joint where the top of the brick meets the wood framing and soffit.
Why is there a gap between my brick and the frieze board?: The brick veneer rests on the foundation edge, while the frieze board is attached to the roof and wall framing. If the foundation edge drops, the brick drops with it and a gap opens at the top under the trim.
Is a frieze board gap always a foundation problem?: No. A gap that is wider at one corner, comes with stair-step brick cracks below, or changes with the seasons is more likely to reflect foundation movement; an even gap with no brick cracks or interior signs points elsewhere.
Frieze board or trim gap: How do I measure it?: Measure the gap at regular points along the wall, especially at corners, photograph each point with a ruler, and repeat through a summer and winter to see whether it changes.

What does a gap under the baseboard mean for my foundation?

It shows the floor and the bottom of a wall have moved apart, a listed sign of foundation movement on shrink-swell clay. A floor survey shows which part moved.

Gaps under baseboards: What does this sign look like?: A visible gap between the floor and the bottom edge of a baseboard, often wider at one end of the wall; Flooring that has dropped away from the trim, leaving the baseboard hanging above it; A baseboard that has been pushed up, with its top joint or caulk line cracked.
Gaps under baseboards: Why does the floor pull away from the wall?: Baseboards are nailed to the wall, and the wall and floor are separate parts of the house.
Gaps under baseboards: Which movements can open the gap?: Edge lift (perimeter wetting heave): soil under the perimeter becomes wetter than under the interior and swells; Center lift or edge drop (perimeter drying settlement, center heave): soil around the perimeter dries and shrinks; Corner lift: on a uniformly loaded rectangular slab, the corners press on the soil with about one-fourth the pressure of the center, so corners tend to lift relative to the middle when clay swells.
Gaps under baseboards: How is it documented?: Gap width at each location, the wall it is on and the date; Repeat readings over time, since the ASCE homeowner guide advises monitoring existing cracks for progressive or seasonal movement; Nearby signs: sloping floors, doors binding or tapered gaps, diagonal drywall cracks at openings.
Gaps under baseboards: Is a gap between the floor and baseboard a foundation problem?: It can be. Civil engineering guidance lists walls separating from floors as a visible sign of inadequate foundation performance, but it also notes that seeing one listed condition does not by itself prove a structural problem.
Gaps under baseboards: Can the floor rise instead of sink?: Yes. Expansive clay that gets wetter swells and can lift a building, and soil that dries can shrink and let it settle. A gap under a baseboard shows the floor and wall moved relative to each other, not which one moved.
Gaps under baseboards: Can cutting down a tree cause the floor to rise?: Engineering guidance says removing a tree near a foundation may cause upheaval as soil moisture increases, especially if the tree was there before the house was built.
Gaps under baseboards: How is the gap measured?: The gap width is recorded at each location with the date. A homeowner guide from civil engineers advises monitoring cracks for progressive or seasonal movement, and a floor elevation survey shows where the floor is high or low.

What does a horizontal crack at the brick ledge or slab edge mean?

It can come from brick and concrete moving against each other, the slab edge lifting or dropping, or frost or soil pressure; a floor survey helps tell which.

What does this crack look like?: The brick ledge is the narrow shelf at the outside edge of a slab or grade beam (a thickened concrete beam around the perimeter) where the first row of brick sits.
Horizontal crack at brick ledge: Why does it happen?: Fired clay brick takes on moisture and expands permanently, with most of that growth in the first weeks after firing and a slower rate for years. Concrete does the opposite and shrinks as it cures.
Horizontal crack at brick ledge: How is it documented?: Width and offset. Record the crack width and whether one side sits higher or farther out than the other. A clean crack edge suggests recent movement, while a dirty or previously filled crack may be inactive; Change over time.
What is the brick ledge on a slab foundation?: It is the stepped shelf along the outside edge of the slab or grade beam where the bottom course of brick veneer sits. Cracks often show up at this line because the brick and the concrete move differently.
Is a horizontal crack at the bottom of my brick always foundation movement?: No. Clay brick expands permanently over time while concrete shrinks, and that difference alone can crack the concrete or pull brick away at the base. Soil movement such as edge lift can also cause it, so the crack is read together with an elevation survey.
Can frost cause a crack at the slab edge in Oklahoma?: Frost heave is one possible cause of horizontal cracking in shallow elements. Inspection guidance suggests suspecting frost when the damage sits above the local frost depth or appeared after a cold snap.
How do I tell if the crack is still moving?: A clean crack edge suggests recent movement, while a dirty or previously filled crack may be inactive. A crack monitor read over six months or more can show seasonal opening and closing.

What does a horizontal crack or bow in a basement wall mean?

It usually means soil outside is pushing the wall harder than it was built to resist, from wet soil, swelling clay, frozen soil or poor backfill.

Basement wall crack or bow: What does this sign look like?: The crack runs roughly level along a poured concrete or concrete block wall, often near mid-height, and the wall above or below it may lean or bulge into the room. In block walls the crack can also follow the mortar joints in a stair-step line before turning horizontal.
Why do basement walls get pushed in?: A basement wall works like a retaining wall: soil presses against the outside face, and the wall must resist it. The general name for this is lateral pressure, meaning sideways force. When that force grows, the wall cracks and moves inward.
Basement wall crack or bow: How is it documented?: Crack pattern and width. Note whether the crack is horizontal, stair-stepped or both, and whether water stains or white mineral deposits are present. A clean crack suggests recent movement, while a dirty or filled crack may be older; Amount of bow or lean.
Basement wall crack or bow: What repair approaches exist?: Inspection guidance lists careful jacking, interior buttresses, epoxy grout injection, and lowering the outside grade to reduce pressure as repair approaches. Large bulges are described as needing to be tied back to the structure, while small ones may be pinned or rebuilt.
What causes a basement wall to crack horizontally?: The usual cause is pressure from the soil outside pushing the wall inward. Saturated soil, swelling clay, frozen soil, improper backfilling and heavy equipment vibration nearby are all described as sources of that pressure.
Is a horizontal basement wall crack more serious than a vertical one?: Inspection guidance calls horizontal or sweeping cracks potentially serious because they mean the wall has been bent or broken by sideways force. Vertical shrinkage cracks in block walls are described as rarely serious.
How is a leaning or bowing wall judged unsafe?: A common inspection rule says a wall is usually considered unsafe if a plumb line through its center of gravity falls outside the middle third of its base. In that case a structural engineer's evaluation is typically called for.
Basement wall crack or bow: Does water make the pressure worse?: Yes. Clogged drains let water pressure build against the wall, and wet clay backfill swells. Most damp foundations are traced to poor surface drainage and poor backfill.

What does a stair-step brick crack wider at the bottom mean?

It suggests the wall was pushed apart from below, often as swelling clay lifted part of the foundation. An elevation survey confirms heave or settlement.

What does this crack look like?: The crack steps through the mortar joints in a staircase line, usually from a corner, window or door, and it opens widest near its lower end, closing to a hairline higher up. Stair-step cracking in brick veneer is a well-documented distress pattern on expansive soils.
Stair-step crack, wider at bottom: What does the taper tell you?: Movement cracks in brick taper, wide at one end and hairline at the other. The wide end marks where the wall has separated most.
Stair-step crack, wider at bottom: What are the common causes?: Heave is upward movement of a foundation caused by soil swelling. Expansive clay absorbs water and swells, and upward movements of 6 to 8 inches or more have been reported in central Texas clays. Under a slab, the perimeter can rise when the soil swells and drop when it shrinks.
Stair-step crack, wider at bottom: How is heave or settlement confirmed?: Elevation survey. A relative floor elevation survey, drawn on a plan, is the engineering step beyond a visual first impression. See elevation surveys; Crack activity. A clean crack edge suggests recent movement; a dirty or previously filled crack may be inactive; Monitoring.
What does it mean when a brick crack is wider at the bottom?: It suggests the wall has been pushed apart from below, which fits part of the foundation rising (heave) or a neighboring section dropping. Because both can produce a similar crack, an elevation survey is used to tell them apart.
Stair-step crack, wider at bottom: Can clay soil push a foundation up?: Yes. Expansive clay swells as it gains moisture, and the edges of a slab can rise when the soil under them swells. Upward movements of 6 to 8 inches or more have been reported in central Texas clays.
Can removing a tree cause this kind of crack?: It can. Soil where a tree was recently removed may be drier than the soil around it and can swell as it re-wets, causing localized heave, especially for trees that predate the house.
Stair-step crack, wider at bottom: Can piers installed during a repair be lifted?: Engineering literature notes that inadequately anchored piers can be lifted by swelling clay, and that even the full weight of the structure is usually not enough to resist expansive forces.

What does a stair-step brick crack wider at the top mean?

It usually points to settlement: part of the foundation below dropped. On Oklahoma clay, soil drying under the slab edge, often near trees, is most common.

What does this crack look like?: The crack follows the mortar joints in a staircase line, usually starting near a corner, window or door, and it is visibly wider at its upper end and closes to a hairline lower down.
Stair-step crack, wider at top: What does the taper tell you?: Brick industry guidance states that foundation settlement, especially on unstable or expansive soils, can cause diagonal or stepped cracks in brick and mortar directly above the foundation, and that settlement and deflection cracks have a tapering shape.
What commonly causes this crack?: Settlement from fill, soft alluvial soil and collapsible soil are other listed mechanisms, covered in the causes section.
How is this crack documented?: Width at both ends. Measure the crack at the top and bottom with a crack-width card, and photograph it with a scale in the frame; Age and activity. A clean crack edge suggests recent movement; a dirty or previously filled crack may be inactive.
What does a stair-step crack in brick mean?: A crack that steps up through the mortar joints is a common pattern of foundation movement in brick veneer. Brick industry guidance notes that foundation settlement, especially on unstable or expansive soils, can cause diagonal or stepped cracks in the brickwork directly above the foundation.
Why does it matter whether the crack is wider at the top?: Settlement and deflection cracks taper, wide at one end and hairline at the other. The wide end shows where the wall has pulled apart most, which helps identify which part of the foundation has moved, but an elevation survey is used to confirm it.
Is a wide crack in an old house as serious as in a new one?: Not necessarily. Inspection guidance relates crack width to building age: a half-inch crack in a new building may indicate rapid settlement, while in a 50-year-old building it may reflect slow movement of about 1/100 inch per year.
How do I know if the crack is still moving?: A clean, fresh crack edge suggests recent movement, while a dirty or previously filled crack may be inactive. A crack monitor read over six months or more can show seasonal movement.

What does it mean when clean-edged cracks appear suddenly?

Several new, sharp-edged cracks at once point to a sudden cause such as an earthquake, blasting or an impact, rather than slow seasonal clay movement.

Sudden clean-edged cracks: What does a "fresh" crack look like?: Crack faces are sharp and bright, with no rounding; No dust, cobwebs or debris inside the crack; No paint, caulk or patching compound bridging it.
How does it differ from soil-movement cracks?: Expansive clay moves on a seasonal cycle. Texas monitoring found slabs settling through the growing season and partly recovering in winter, so cracks from soil movement tend to grow, open and close over months.
Sudden clean-edged cracks: How should it be documented?: Write down the date and time the cracks were first noticed, and anything that happened just before (a felt earthquake, blasting, a storm); Take close-up photos of each crack with a ruler or coin for scale, showing the clean faces; Photograph wider views so each crack's location is clear.
Sudden clean-edged cracks: What are the next steps?: Compare with the distress pattern library and the symptom matrix. For insurance questions, see insurance claims.
What does a fresh, clean crack mean?: A crack with sharp faces and no dirt, paint or caulk inside it is recent. When several appear at the same time, that supports a sudden cause such as an earthquake or impact rather than slow soil movement.
Sudden clean-edged cracks: How do I tell an old crack from a new one?: Old cracks usually have rounded or dirty edges, dust or debris inside, paint or caulk bridging them, or a history in earlier photos. New cracks have bright, sharp faces and no coating inside.
Sudden clean-edged cracks: Could an Oklahoma earthquake have cracked my house?: Oklahoma has had many felt earthquakes since 2009, including magnitude 5.7, 5.8 and 5.0 events in 2011 and 2016. Matching the date the cracks appeared with the earthquake record is the first step.
Can soil movement cause sudden cracks?: Sometimes. Expansive clay usually moves gradually, but on clay a crack typically needs about 5 to 10 millimeters of movement before it shows, so it can seem to appear all at once; that is why the overall pattern of cracks and floor levels still needs checking.

Why are my cabinets or countertops pulling away from the wall?

The floor or wall may have moved; on Oklahoma clay one cause is center heave, where the slab interior rises, though cabinets also loosen for ordinary reasons.

Why do cabinets show foundation movement?: Base cabinets sit on the floor and are screwed to the wall; upper cabinets hang from the wall framing; countertops span across the base cabinets. When the floor under one end rises or drops, or the wall tilts, the straight lines of cabinets and counters reveal it.
Cabinets separating: How does center heave cause it?: This site links the sign to center heave (moisture build-up under slab). Center lift happens when swelling is concentrated under the middle of a building, or when the edges shrink, so the center ends up high.
Cabinets separating: What else can cause it?: Home inspection standards list uneven floors, drywall cracks, brick cracks and out-of-square door frames as signs of possible foundation movement to report.
Cabinets separating: How can it be checked?: Put a level on the countertop front to back and side to side, and note the low direction; Measure gaps between cabinets and wall, and between countertop and backsplash, at marked spots; Photograph each gap with a ruler in view, and repeat over several months.
Cabinets separating: What are the next steps?: Plot it on the elevation survey, compare with the distress pattern library, and use the symptom matrix to weigh likely mechanisms.
Why are my kitchen cabinets pulling away from the wall?: If the floor under the cabinets or the wall behind them has moved, the gap can open. On expansive clay, one possible cause is center heave, where soil under the middle of the slab swells and lifts interior areas relative to the edges.
Can a gap behind cabinets be something other than foundation movement?: Yes. Installation or fastener problems can also open gaps. Checking whether the floor and countertop are out of level, and whether other signs are present nearby, helps sort it out.
Cabinets separating: How do I check if my countertop is out of level?: Use a level along the front and sides of the counter and note which direction is low. Comparing that with a floor elevation survey shows whether the floor has moved in the same direction.
Cabinets separating: What is center heave?: Center heave, also called center lift, is swelling concentrated under the middle of a building, or shrinkage under its edges, so the interior ends up high relative to the perimeter.

Why are my floor tiles cracking in a straight line?

A crack running through several tiles usually follows a crack or bend in the slab below, often from clay swelling under part of it or edges settling.

Why does tile show slab cracks?: Ceramic and stone tile is bonded tightly to the slab. Tile is stiff and brittle, so it cannot stretch across a crack that opens beneath it. When the slab cracks or bends, the tile directly above it cracks along the same path.
Tile cracks in a line: How do you document it?: Trace the line from end to end and mark the ends with tape and a date; Measure the width at the widest point and check whether one side is higher than the other (a height difference, or offset); Photograph with a ruler in view, including a close-up of any offset.
Tile cracks in a line: What happens next?: If a leak is suspected, plumbing leak detection and repair comes first, since the moisture source drives the heave. For other mechanisms, compare the crack map with the distress pattern library and the symptom matrix.
Why are my floor tiles cracking in a line?: A crack that runs straight through several tiles usually follows a crack or movement in the concrete slab underneath. The tile is bonded to the slab, so when the slab cracks or bends, the tile above it cracks along the same line.
Does a tile crack line mean my foundation is failing?: Not by itself. Concrete slabs commonly crack, and a single stable crack may simply be telegraphing through. A line that widens, shows a height difference across it, or comes with a floor hump or wall cracks points toward ongoing soil movement.
Can a plumbing leak cause tile to crack?: It can on clay soil. Leaking pipes add water that can worsen swelling of the soil under the slab, lifting that area and cracking the slab and tile above it.
How do I document a tile crack?: Trace the full length of the line, measure its width and any height difference between the two sides, photograph it with a ruler, and mark it on a floor plan so it can be compared with a floor elevation survey.

Why are retaining walls, fences and trees leaning on my slope?

When they all lean the same way, the upper soil may be slowly creeping downhill, which can also pull at foundations near the slope.

Leaning walls, fences, trees: What does this sign look like?: Retaining walls tipping outward or bulging at mid-height; Fence posts leaning downhill in a row, or fence lines that have bowed; Trees tilted downhill.
Leaning walls, fences, trees: Why does it happen?: Creep is very slow downhill movement of the upper soil, often too slow to see except through its effects on things anchored in it. Inspection guidance notes that clay soils on slopes can slowly drift downhill, causing settlement.
Leaning walls, fences, trees: How is it documented?: A common inspection rule says a wall is usually considered unsafe if a plumb line through its center of gravity does not fall within the middle third of its base, and that a structural engineer should be consulted in that case. Floor readings are covered in elevation surveys.
Leaning walls, fences, trees: How is drainage handled on sloped lots?: Building guidance calls for grassy swales (shallow drainage channels) to slope at least about 1 percent and no more than about 15 percent unless lined with riprap, meaning rock armor.
Why are the fence posts and trees on my slope leaning downhill?: Features that lean the same way on a slope can indicate the upper soil is slowly moving downhill. Clay soils on slopes can gradually drift downward, a process called creep.
When is a leaning retaining wall considered unsafe?: A common inspection rule says a wall is usually considered unsafe if a plumb line dropped through its center of gravity falls outside the middle third of its base. In that case a structural engineer's evaluation is typically called for.
Leaning walls, fences, trees: Does Oklahoma have landslides?: Yes. The Oklahoma Geological Survey monitors and maps landslides statewide, with research focused on shallow landslides in eastern Oklahoma.
Leaning walls, fences, trees: Can slope movement affect my house foundation?: Yes. Downhill drift of clay soil can cause settlement of structures on or near the slope, which may show as cracks and floors sloping toward the downhill side.

Why are the floors bouncy or soft in my crawl space home?

Bouncy or soft floors usually point to framing or support problems, such as moisture-damaged wood or supports that are missing, too far apart or failing.

Bouncy or soft floors: Where does this sign appear?: Bouncy or soft floors are a sign for houses with a wood floor system over a crawl space: pier and beam crawl space homes and manufactured homes on piers. In these houses the floor is built from joists (parallel wood framing members) resting on beams, which rest on piers or posts.
What can bouncy floors mean?: Toughness is lost first, then bending strength, then all strength properties; A 5-10% loss of wood weight to decay matched a 20-80% drop in mechanical properties in laboratory tests; At 10% weight loss, bending strength fell about 40%.
Bouncy or soft floors: What gets checked?: Home inspection standards call for inspecting the crawl space and structural components and reporting:
How are bouncy floors repaired?: Repairs depend on which mechanism is found. Crawl space repair covers adding or replacing posts and piers, sistering or replacing damaged joists and shimming beams. Where moisture is the driver, crawl space encapsulation and drainage solutions address the source of the water.
Are bouncy floors a foundation problem?: In crawl space homes, bounce or softness usually comes from the wood framing or the supports under the floor rather than from soil movement. Moisture damage to wood and missing or failing supports are the two main causes this site tracks.
What does an inspector check under a bouncy floor?: Home inspection standards call for inspecting the crawl space and structural components and reporting wood in contact with or near soil, signs of active water penetration and cut or notched framing that may be a structural concern.
Bouncy or soft floors: Can wood floor framing sag over time even without damage?: Yes. A U.S. Forest Products Laboratory study of wood roof trusses under constant load found total deflection grew to about two to three times the initial deflection, with about half of the time-related sag in the first year.
Bouncy or soft floors: How wet does wood have to be to rot?: Decay fungi need wood above its fiber saturation point, about 30% moisture content, which takes free water from rain, condensation or wet ground contact. Air-dried wood is usually at or below 20% and generally does not decay.
Bouncy or soft floors: Can a joist that looks fine still be weak from rot?: Yes. Early decay is often visible only under a microscope, yet laboratory tests show a 5-10% loss of wood weight can cut mechanical properties by 20-80%.

Why do cracks open and close with the seasons?

Expansive clay shrinks as it dries and swells as it rewets, so the house moves with it and cracks widen in dry months and tighten in wet months.

Why do cracks open and close?: Expansive clay swells when it gets wet and shrinks when it dries, creating a repeating cycle of movement in the upper soil. The zone of seasonal moisture change can extend from 3 to 40 feet deep depending on the site.
What is Oklahoma's seasonal cycle?: More than 75% of Oklahoma has bedrock that can produce expansive soils, including clay-rich shales that can swell to 1.5 to 2 times their dry volume when wet. Soil moisture drops faster during hot, dry periods than during cool, wet ones.
Seasonal opening cracks: What mechanisms produce it?: Engineering guidance on expansive soil notes that lack of watering in drought, which dries the clay, can be more damaging than overwatering, and that the goal is steady soil moisture.
How do you track a seasonal crack?: Mark the ends of the crack and two or three measuring points along it; Measure width at the same points with a crack gauge or ruler, or install a crack monitor across it; Photograph each point with a scale in view.
Seasonal opening cracks: What does it rule in and out?: Seasonal opening and closing points toward moisture-driven soil movement. It argues against causes that happen once, such as a single earthquake or impact, which tend to leave fresh, clean-edged cracks that do not cycle; see fresh, clean-edged cracks appearing suddenly.
Seasonal opening cracks: What are the next steps?: Plot the cracks on an elevation survey, compare them with the distress pattern library, and use the symptom matrix.
Why do my cracks get bigger in summer and smaller in winter?: On expansive clay, soil shrinks as it dries in hot weather and swells when it rewets, so the foundation moves in a yearly cycle. Cracks in the house open and close with that movement.
Seasonal opening cracks: Does a crack that closes in winter mean the problem fixed itself?: Not necessarily. Texas monitoring of slabs on expansive clay found partial recovery in winter after summer settlement, so the crack may reopen the next dry season.
Seasonal opening cracks: How long should I monitor a crack?: At least a full year, so both the driest and wettest parts of the cycle are captured. Readings every month or two at the same marked points work well.
Can trees make seasonal cracks worse?: Yes. Trees draw the most water in the growing season, and monitoring has found that drought during the growing season makes slab settlement worse.

Why does my floor sag between piers in a crawl space?

It is usually a framing and support problem: interior piers that settled or tilted, spans too long for the load, or wood damaged by moisture.

What does a sagging floor look like?: The floor feels soft or low in the middle of a room or along a hallway, then firms up near walls or over a beam. Furniture may rock, and a level laid across the floor shows a dip rather than a steady slope in one direction.
Why do floors sag between supports?: Interior piers that settle or rotate drop or lean, which reduces their bearing capacity, and a wood frame tends to flex or sag to follow them.
How is a sagging floor documented?: Floor survey. An elevation survey shows whether the low areas sit between supports (a framing pattern) or along one side of the house (a perimeter foundation pattern). See elevation surveys; Crawl space inspection.
How is a sagging floor repaired?: Engineering guidance for crawl space floors lists:
Why does my floor dip between the piers under the house?: Common causes are interior piers that have settled or tilted, beams or joists spanning too far for their load, and wood weakened by moisture and decay. The wood frame flexes or sags to follow the supports that have dropped.
What deflection is considered too much for a floor?: The building code limit for live-load deflection of floor members is L/360, meaning the span length divided by 360. Engineering guidance also uses that ratio as a benchmark when judging foundation deflection.
Are shims a normal way to level a pier-and-beam floor?: Engineering guidance lists adding hardwood or steel shims on top of pier caps as a way to adjust floor framing, along with replacing or reinforcing damaged members and adding supports where spans are too long.
Does crawl space moisture affect sagging floors?: It can. Unmanaged crawl space moisture can damage wood flooring and framing, and rotting wood members are cited as a structural concern. Controls include ground vapor barriers, cross ventilation, drainage and ground clearance for wood.

Why is brick pulling away from my window or door frame?

Usually the foundation edge carrying the brick has dropped, often as perimeter clay dries and shrinks. The gap tends to be widest in late summer and drought.

Brick gap at window or door: Why does the gap open?: Brick veneer is a single layer of brick tied to the wood-framed wall behind it and resting on a ledge at the edge of the foundation. Windows and doors are attached to the wood framing.
Brick gap at window or door: How do Oklahoma soils cause it?: More than 75% of Oklahoma has bedrock that can produce expansive soils, and clay-rich shales can swell to 1.5 to 2 times their dry volume when wet.
Brick gap at window or door: What else should you look for?: Separation at frames rarely appears alone. Check the same wall for:
Brick gap at window or door: How do you document it?: Measure gap width at the same points on each frame, top and sides; Photograph each gap with a ruler or crack gauge in view; Repeat every month or two through at least one summer and winter.
Brick gap at window or door: What are the next steps?: Plot the sign on an elevation survey, compare it with the patterns in the distress pattern library, and use the symptom matrix to weigh likely mechanisms.
Why is my brick pulling away from the window frame?: A common cause is the outer edge of the foundation dropping as clay soil under it dries and shrinks. The brick moves with the foundation while the window frame, attached to the wood wall, does not move the same way, so a gap opens.
Brick gap at window or door: How much movement does it take to see cracks?: Horticultural guidance on trees and clay soils notes that cracks usually need about 5 to 10 millimeters of movement before they appear, often around windows and doors.
Brick gap at window or door: Does the gap change with the seasons?: It can. Monitoring of slabs on expansive clay in Texas found settlement growing through summer and drought and partly recovering in winter, so gaps tied to soil drying often widen in late summer.
Brick gap at window or door: How should I measure the gap?: Measure the gap width at the same spots with a ruler or crack gauge, photograph it with a scale, and repeat every month or two so the trend through the seasons is clear.

Why is my chimney pulling away from the house or leaning?

Its heavy footing at the edge of the house can settle, or the soil under it can be soft or drying. Earthquake shaking is another possible cause in Oklahoma.

Why do chimneys move differently from the house?: Most of a house is light wood framing spread along long foundation beams. A brick or stone chimney concentrates a great deal of weight on a small footing. That difference means the chimney can settle or tilt on its own even when the rest of the foundation is moving only a little.
Chimney separating or leaning: How should it be documented?: Measure how far the chimney is out of plumb over a known height with a level or plumb line; Measure the gap between chimney and wall at the bottom, middle and top; Photograph cracks in the chimney with a scale, and note whether crack edges are clean or weathered.
Chimney separating or leaning: What are the next steps?: Compare the pattern with the distress pattern library and the symptom matrix. For a chimney that continues to move, see working with engineers.
Why is my chimney pulling away from the house?: An exterior masonry chimney is heavy and usually sits on its own footing. If that footing settles more than the house foundation, or the soil under it is soft or drying, the chimney tilts and a gap opens at the wall or roofline.
Can earthquakes damage chimneys in Oklahoma?: Earthquake shaking is one of the possible causes tracked for this sign. Oklahoma has had several moderate earthquakes, including the magnitude 5.7 Prague event in 2011 and the magnitude 5.8 Pawnee event in 2016, and a chimney that cracked right after a felt quake points toward shaking.
How do I measure a leaning chimney?: Hold a level or plumb line against the chimney face and measure how far it is out of plumb over a known height, and measure the gap at the wall at the top and bottom. Repeat the measurements over time to see if it is moving.
Do home inspectors check chimneys?: Home inspection standards include inspecting the chimney from ground level or the eaves, and reporting signs of possible foundation movement such as brick cracks.

Why is my driveway or patio lifting, sinking or cracking?

Thin slabs on Oklahoma clay lift when soil swells and sink when it washes out, compresses or dries. This alone does not mean the house foundation moved.

Why does flatwork move so easily?: "Flatwork" means exterior concrete slabs: driveways, walks, patios, porches and pool decks. They are usually a few inches thick, carry little weight and sit on the top layer of soil, the layer whose moisture changes most.
Does flatwork movement mean the house moved?: Engineering guidance on expansive soil recommends keeping soil moisture steady around a building and mentions surrounding it with concrete paving as one way to limit moisture changes.
How do you document flatwork movement?: Note which way each slab has moved: lifted, sunk or tilted, and toward or away from the house; Measure height differences at joints and cracks with a ruler or level; Photograph with a ruler in view, and record the season and recent weather.
How is flatwork repaired?: Options matched to flatwork include slabjacking and polyurethane to raise settled slabs, void and compaction grouting, and drainage solutions to deal with the water.
Lifted or sunken flatwork: Why is my driveway or sidewalk lifting?: On expansive clay, soil under the slab swells when it gets wet and pushes thin concrete up. Frost heave in freezing weather and tree roots growing beneath the slab can also lift flatwork.
Lifted or sunken flatwork: Why is my patio sinking?: Common reasons are water washing soil out from under the slab, loose fill compressing over time, and clay shrinking as it dries.
Does cracked flatwork mean my house foundation is moving?: Not necessarily. Driveways, walks and patios are thin and lightly loaded, so they react to soil movement more readily than the house. Flatwork movement is a useful clue about water and soil around the house, but the foundation is evaluated separately.
Can flatwork send water toward my foundation?: Yes. A patio or walk that has settled or tilted toward the house can direct rain against the foundation, adding moisture to the soil there.

Why is my garage door gap uneven or the header sagging?

One side of the garage foundation may have dropped, or the lintel or door hardware may be at fault, so floor level, opening and brick are checked together.

What does an uneven garage door look like?: The closed door touches the floor on one side and leaves a wedge-shaped gap on the other; The weather seal is crushed at one end and open at the other; The header, the beam that spans over the door opening, dips in the middle or is visibly lower at one end.
Uneven garage door or header: Why does it happen?: Expansive soils are common across most of Oklahoma, and seasonal moisture loss lets the clay shrink and the foundation edge move downward. If one side of the garage door opening drops more than the other, the opening tilts and the door no longer closes evenly.
Uneven garage door or header: How is it documented?: A relative floor elevation survey is the engineering step beyond a visual first impression. Readings at the two sides of the opening are compared with each other and with the house floor, since a garage floor is not always built level.
Why is the gap under my garage door wider on one side?: Either the slab or the door opening is out of level. If one side of the garage foundation has dropped, the floor and the opening tilt together and the closed door no longer meets the floor evenly. Door hardware and track adjustment can also cause an uneven gap, so the floor is measured before drawing conclusions.
What makes the brick above a garage door crack?: Brick over a wide opening is carried by a steel angle called a lintel. If the lintel deflects, the brick cracks in a pattern that is widest at the steel angle and tapers to nothing. Foundation settlement at one side of the opening can also crack the brick.
Are garage slab cracks a sign of foundation problems?: They can be. Building officials in expansive-soil areas list cracks in garage slabs among the signs of foundation movement, but concrete also cracks for other reasons, so offset and pattern are evaluated.

Why is the soil pulling away from my foundation?

Clay along the house has dried and shrunk. The gap is a moisture sign, not proof of damage, but the same drying under the slab edge lets the perimeter settle.

What does a soil gap look like?: The soil has separated from the foundation beam or stem wall, leaving a gap you can put a finger or a probe into. The ground nearby may be broken into many-sided blocks by cracks. These are dry-season features of clay soil.
Soil gap at foundation: Why does clay pull away?: Expansive clay swells when water enters it and shrinks as it dries out. Most of Oklahoma has these soils. In the dry season they form deep cracks in roughly polygonal patterns; one documented crack was at least 32 inches deep.
Soil gap at foundation: What can it mean for the house?: The slab-edge pattern works in both directions: the perimeter drops when the soil shrinks and rises when it swells. It is covered in perimeter drying settlement.
Soil gap at foundation: How is it documented?: Gap size. Record the width and the depth a probe reaches, and where along the house the gap is largest; Timing. Note the season and recent rainfall, since the gap reflects current moisture; Floor survey.
Soil gap at foundation: How do moisture and grading around the house matter?: Uneven moisture from lawn watering is one cause of differential movement. Federal building guidance calls for the ground next to a house to slope away, typically about 6 inches of fall over the first 10 feet, and for the grade near the foundation to be kept from settling.
Why is there a gap between the soil and my foundation?: Expansive clay shrinks as it dries, so in dry weather it pulls back from the foundation and splits into cracks. The gap is a sign that the soil along the house has lost moisture.
Soil gap at foundation: How deep do clay shrinkage cracks go?: Dry-season cracks in expansive clay form rough polygon patterns, and one documented crack was at least 32 inches deep. The zone of seasonal moisture change can extend from about 3 to 40 feet deep depending on the site.
Does soil pulling away mean my foundation is settling?: Not necessarily, but it is a drying indicator. When clay under the slab edge shrinks, the perimeter of the slab can drop, which can show up as wall and brick cracks and skewed door and window frames.
Soil gap at foundation: Do trees make the gap worse?: Trees and large shrubs withdraw water from the soil and can cause downward foundation movement. Gaps and cracks that are worst near a tree fit that pattern.

Why is there a gap between my ceiling and an interior wall?

Either swelling soil has pushed the floor and wall up (foundation heave) or roof trusses have bowed up and lifted the ceiling (truss uplift).

Ceiling-wall gap: What are the two possible causes?: Center heave (moisture build-up under slab); Perimeter wetting heave (edge lift); Leak-induced localized heave, since leaking pipes can worsen swelling of nearby clay.
Ceiling-wall gap: How do you tell them apart?: A crack where the tape is torn through at the corner, with the ceiling fastened to the truss bottoms, points toward uplift; a crack running along the edge of the tape may instead be a taping problem. See nail pops and tape-joint cracks.
Ceiling-wall gap: How do you document it?: Measure the gap at marked points along each affected wall; Note the date and repeat monthly through a winter and a summer; Look in the attic above the gap for trusses lifted off the top of the wall.
Ceiling-wall gap: What happens next?: For truss uplift, trade and inspection literature describes the problem as not structural, and fixes involve letting the ceiling drywall float near interior walls with clips or slotted connectors.
Why is there a gap between my ceiling and an interior wall?: The two common causes are the floor and interior wall being pushed up by swelling soil, or the roof trusses bowing upward and lifting the ceiling. The first is foundation heave; the second, truss uplift, is a roof framing effect.
Ceiling-wall gap: How can I tell truss uplift from foundation heave?: Truss uplift cracks typically open in winter and close in summer, and the floor stays level. Heave raises the floor and wall, which shows on a floor elevation survey and often comes with other signs such as sticking doors or floor cracks.
Ceiling-wall gap: Should I look in the attic?: Yes. Inspecting the attic framing above the crack is part of diagnosing truss uplift; a truss bottom chord bowed up above the wall points to uplift.
Ceiling-wall gap: Is truss uplift dangerous?: Building trade and inspection literature describes truss uplift cracks as alarming-looking but not a structural problem.

Why is there a gap under my slab edge or footing?

Supporting soil has been removed, most often by running water, though settling fill, collapsing soil and slope movement can also leave a void.

Exposed slab edge or void: What are you seeing?: A slab-on-grade foundation has a thickened outer beam that is meant to be buried in soil, and footings under other foundation types are meant to bear on soil.
Exposed slab edge or void: What can cause it?: Engineering guidance for houses on expansive soil recommends keeping soil moisture steady, and suggests surrounding the building with paving or removing perimeter planter beds to limit moisture changes. See surface drainage and grading and water ponding near foundation.
Exposed slab edge or void: How is it documented?: Probe the void with a thin rod or tape and record how far it reaches under the slab and how tall it is, at several points; Measure the length of exposed or undermined edge; Photograph each point with a ruler or tape in view.
Exposed slab edge or void: What can it lead to?: Where support is lost, that section of the foundation can settle or crack. Check nearby walls and floors for stair-step brick cracks, horizontal cracks at the brick ledge or slab edge and sloping floors.
Exposed slab edge or void: How is it repaired?: Repair usually has two parts: stopping the water or soil loss, and restoring support. Options include drainage solutions, void and compaction grouting, slope and erosion stabilization, and piering where the edge has already settled.
Why can I see under the edge of my slab?: Soil that once covered and supported the slab edge has been removed, most often by water running along or under the foundation. Settling fill, collapsing soil and soil creeping down a slope can also open a gap.
Is a void under the footing serious?: A footing is designed to rest on soil. Where soil has been removed from beneath it, that section loses support and can settle or crack, so the depth and length of the void matter.
How do I measure a void under the slab?: Probe the gap with a thin rod or tape, recording how far it goes in horizontally and how deep it is at several points, and photograph each spot with a ruler. Note where gutters, downspouts and slopes direct water.
Can underground water create voids I can't see?: Yes. Geologists call underground soil erosion by flowing water piping, and leaking water or sewer lines are a listed cause of ground movement. Swelling clays can also crack concrete channels, and the resulting voids can lead to piping and erosion.

Why is there water, condensation or mold in my crawl space?

Moisture under the house is not being controlled. Keeping humidity below 60 percent helps limit mold, along with a vapor barrier, drainage and ventilation.

What does crawl space moisture look like?: Puddles or saturated soil on the crawl space floor, especially after rain; Water droplets on pipes, ductwork or the underside of the floor; White, green or black growth on joists, beams or insulation, and a musty smell.
Why do crawl spaces get wet?: Federal building guidance states that ground moisture will enter any foundation unless measures are taken, and it places a ground vapor barrier under crawl space construction. For crawl spaces built on a slightly raised mound, a vapor barrier is always recommended.
Crawl space water and mold: Why does it matter for the structure?: Unmanaged crawl space moisture can damage wood flooring and create health and property problems. Engineering repair guidance cites rotting wood members as a structural integrity concern and recommends treated lumber where members are replaced.
Crawl space water and mold: What moisture controls does guidance describe?: Sealing and conditioning the crawl space is covered in crawl space encapsulation.
Crawl space water and mold: How is it documented?: Humidity. A hygrometer (humidity meter) reading in the crawl space and in the house, compared with EPA's 60 percent guideline; Wood moisture and condition. A moisture meter on joists and beams, and probing for soft or decayed wood; Water sources.
What humidity level prevents mold?: EPA recommends keeping indoor relative humidity below 60 percent, ideally between 30 and 50 percent. EPA states that the key to mold control is moisture control.
Why is there condensation on pipes and ducts in my crawl space?: Condensation on cold surfaces such as pipes is a sign of high humidity. EPA suggests drying the wet surface, reducing the moisture source, and insulating cold surfaces such as cold water pipes.
What kind of ground cover should a crawl space have?: Inspection guidance describes a solid 6-mil vapor barrier covering the crawl space floor, overlapped at least 6 inches, taped, and run about 6 inches up the perimeter walls. Federal building guidance also places a ground vapor barrier under crawl space construction.
Can crawl space moisture damage the floor structure?: Yes. Unmanaged crawl space moisture can damage wood flooring and framing, and rotting wood members are cited as a structural integrity concern.

Why is water ponding next to my foundation after rain?

The ground is not carrying water away. On expansive clay, uneven wetting can swell soil and lift part of the foundation, and running water can erode soil.

Water ponding near foundation: What does this sign look like?: Puddles stay along the foundation for hours or days after rain, often at inside corners, under roof valleys, at downspouts that empty against the wall, or where flower beds sit higher than the lawn. Mulch or soil may be washed against the siding.
Why does ponding water matter?: Soil only moves when its moisture content changes unevenly across a site, and poor drainage is a named contributor. Expansive clay is widespread across Oklahoma, and when it swells under the slab edge, the perimeter can rise.
Water ponding near foundation: How do gutters and downspouts factor in?: Downspouts that discharge at the surface should release water at least 2 feet from the building; Each downspout should serve no more than about 50 feet of gutter; Gutter drains should not be connected to the perforated foundation drain.
How is ponding documented?: Photograph where water stands and for how long after a rain, note where each downspout discharges, and measure how far the grade falls over the first 10 feet from the wall.
Water ponding near foundation: How much should the ground slope away from my house?: The International Residential Code calls for the grade to fall at least 6 inches within the first 10 feet from the foundation. Where lot lines or other barriers prevent that, the grade must slope away at a minimum of 5 percent toward drains or swales.
Why is standing water near the foundation a problem on clay soil?: Expansive clay swells when it gets wetter. Water that collects along one side of a house wets the soil unevenly, which can lift the slab edge there, and poor drainage can also erode soil around footings.
Water ponding near foundation: How far should downspouts discharge from the house?: Federal building guidance and foundation design guidance call for downspouts that discharge at the surface to release water at least 2 feet from the foundation, and advise against connecting them to perforated foundation drains.
Water ponding near foundation: How high should the slab be above the dirt?: Foundation design guidance calls for the top of the concrete to sit at least 8 inches above the finished grade next to it.

Why is water seeping where my basement floor meets the wall?

Water at the cove joint and white deposits mean water is moving through the foundation, usually from poor grading, downspouts or a high water table outside.

Cove joint water, efflorescence: What does this sign look like?: Water at the cove joint. The cove joint is the seam where the basement floor slab meets the foundation wall. After rain, a wet line, puddle or trickle appears along that seam; Efflorescence.
Why does water get in?: Hydrostatic pressure is the push of water held in saturated soil. Saturated soil against the outside of a foundation wall can push it inward, producing a horizontal crack along with signs of water intrusion. Clogged drains let water pressure build up against the wall.
Cove joint water, efflorescence: What does the guidance say about fixes?: The source of condensation or exterior water intrusion is corrected before a crystalline waterproofing coating is applied to the concrete; Surface sealants are rarely effective and can trap moisture; water is redirected away from masonry and mortar joints repointed where needed; Basement floors should slope toward drains so water can leave if the space floods.
Cove joint water, efflorescence: How is it documented?: Observe and photograph the wall and cove joint during and after a soaking rain, note which walls are wet, and check where downspouts discharge and how the yard slopes on those sides.
What is the cove joint in a basement?: It is the seam where the basement floor slab meets the bottom of the foundation wall. Water that collects against the outside of the wall can show up along this seam after rain.
Cove joint water, efflorescence: What does white powder on my basement wall mean?: That white deposit is called efflorescence. Inspection guidance treats white powder stains, along with musty odors, as signs of a moisture problem in the wall.
Will sealing the inside of the wall stop the water?: Inspection guidance notes that surface sealants are rarely effective and can trap moisture. The usual approach is to redirect water away from the masonry and correct the source of condensation or exterior water before applying a waterproofing coating.
How common are basement water problems?: A federal housing guide reported that typical construction practices could produce some water problem in as many as 1 in 3 basements within two years, and that most damp foundations are caused by improper surface drainage and poor backfill.