Causes

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

• Can a foundation crack because it was built wrong?Yes. Thin beams, missing or misplaced steel, weak concrete or a poor pad can leave a foundation unable to bridge ordinary soil movement.
• Can a plumbing leak under a slab cause a floor hump?Yes. A supply or drain leak under a slab on expansive clay wets the soil, which swells and pushes up a local floor hump with cracks radiating from it.
• Can earthquakes damage Oklahoma homes and foundations?Yes. Strong shaking can crack chimneys, brick and masonry walls. Most Oklahoma quakes are too small to cause damage, but the larger 2016 events did.
• Can removing a tree make my foundation heave?Yes. A large tree can dry the clay under a house for years; once it is removed, water returns and the clay slowly swells and pushes up what sits on it.
• Can tree roots cause foundation settlement on Oklahoma clay?Yes. Roots under a foundation can dry and shrink expansive clay, so the side or corner nearest the tree settles, worst in summer and drought.
• Can vibration from construction or blasting crack a house?Blasting, pile driving or heavy equipment can stress finishes and lengthen existing cracks, but most Oklahoma home cracking traces to soil movement.
• How does crawl space moisture cause wood rot and sagging floors?Water and humid air in a crawl space raise wood moisture until decay fungi grow, weakening sills, joists and beams so floors feel soft, bouncy or sag.
• How does erosion leave voids under a foundation or slab?Runoff, flooding or a leaking pipe can carry soil from beside or under a foundation, leaving a void where the concrete above can crack or settle.
• Is a concrete crack from shrinkage or foundation movement?Many cracks come from materials shrinking or moving with temperature, not the foundation; a floor elevation survey and crack pattern tell them apart.
• What causes center heave in an Oklahoma slab foundation?Center heave happens when expansive clay under the middle of a slab gains moisture, often from a plumbing leak, swells and pushes the floor up.
• What causes sinkholes and karst subsidence in Oklahoma?Groundwater dissolves gypsum, salt or limestone, forming cavities the soil above can sag or collapse into. Oklahoma has karst in the west, northeast and south.
• What happens when a post-tension slab tendon is cut or fails?That part of the slab loses the compression that helps it resist cracking from soil movement, and cutting a stressed tendon releases a dangerous force.
• What is frost heave and can it lift Oklahoma porches and steps?Frost heave happens when moist, fine-grained soil freezes and grows ice lenses that push up shallow footings, steps, porches and slabs.
• Why are my foundation piers moving after repair?Piers that miss stable soil or rock can be lifted by swelling clay, settle when ending too shallow in shrinking clay, or be dragged down by settling fill.
• Why are the floors sagging over my crawl space?Interior pads settle, wood shims crush or rot, or beams and joists are too small or span too far, so the floor sags, bounces or slopes.
• Why do basement walls crack horizontally and bow inward?Soil pushes sideways on basement walls, and wet backfill and swelling clay add pressure. When the push exceeds the wall's strength, it cracks, bows or slides.
• Why do foundation edges rise after heavy rain?When soil at the perimeter gets wetter than soil under the middle, expansive clay swells and lifts the foundation edges, leaving a dish shape.
• Why do houses on Oklahoma hillsides slowly move downhill?Clay on a slope creeps downhill a little each wet-dry season, and creeks cutting the toe remove support, pulling a house outward and down on its downhill side.
• Why do Oklahoma houses settle on floodplains and soft wet clay?Soft river alluvium and wet clay compress under a house as water squeezes out, causing gradual, largely permanent settlement, most under heavy walls.
• Why do the edges of a house sink in dry Oklahoma weather?Expansive clay around the outside of a house dries and shrinks while soil under the middle stays moist, so the edges sink. It is worst in drought.
• Why does a chimney or column settle more than the rest of the house?A heavy chimney, column or added story can press on the soil harder than it can support, so that spot sinks. It is a soil-strength problem, not a seasonal one.
• Why does dry silty soil in Oklahoma sink when it gets wet?Loose, dry silts hold together only while dry; when water first reaches them under a house, the bonds weaken and the soil compacts, causing sudden settlement.
• Why does my ceiling crack in winter and close in summer?Often truss uplift: roof trusses bow up in cold weather and lift the ceiling off interior walls. It mimics heave, but the floor has not moved.
• Why is my home addition cracking or pulling away from the house?An addition often sits on its own foundation at a different depth or on fill, so it settles or heaves differently and the joint with the house opens up.
• Why is my house rising after foundation repair done in a drought?If piers set a house level while clay is dry and shrunken, returning rain swells the soil under unpiered areas, lifting them above the piered edges.
• Why is my house settling on fill dirt in Oklahoma?Loose fill, or fill with debris or organic matter, slowly compresses under a house. Wetting speeds it up, and it is worst where the fill is deepest.