Foundation Cracks: When Should You Worry?
by the Berry team · Updated
Thin vertical cracks in a poured concrete foundation are common, usually from the concrete shrinking as it cured, and they mostly matter if they leak water. Worry more about horizontal cracks, stair-step cracks in block or brick, cracks wider than about a quarter inch, cracks that keep growing, or cracks that show up alongside sticking doors and sloping floors, and have those looked at by a structural engineer.
What foundation cracks mean and what they cost to fix
Ordered roughly from least to most serious. Ranges are typical US prices. Structural repair prices vary widely with the cause and the size of the house, so get an engineer's opinion before getting repair quotes.
| Crack | What it usually means | DIY cost | Pro cost |
|---|---|---|---|
| Hairline vertical crack in poured concrete | Shrinkage from curing. Very common, usually not structural. Matters if it leaks. | DIY$20-$60 for a crack sealing kit, if it is dry and not leaking | Pro$300-$800 to inject and seal one crack |
| Vertical crack that leaks water | Same type of crack, but groundwater is getting through. Often worse with clogged gutters or poor grading. | DIY$0-$100 to fix grading and downspouts first | Pro$300-$1,000 to inject, more for exterior waterproofing |
| Crack wider than about 1/4 inch, or one side higher than the other | Possible settlement or movement. Worth a professional opinion. | DIYMonitor and document | Pro$300-$800 for a structural engineer evaluation |
| Stair-step crack in block or brick | Follows the mortar joints. Can mean settlement, especially if it is wide or growing. | DIYMonitor and document | Pro$500-$2,000 for tuckpointing, much more if the wall is moving |
| Horizontal crack or bowing wall | Soil pressure pushing the wall inward, common in block basement walls. The most serious type. | DIYNot a DIY job | Pro$4,000-$15,000+ to brace or anchor a wall, depending on method and length |
| Settling foundation | Cracks plus sticking doors, sloping floors, or gaps at window and door frames. | DIYNot a DIY job | Pro$1,000-$3,000 per pier, with whole jobs often $5,000-$15,000+ |
Ranges are typical US prices and vary with your region, your home, and the season. A pro quote for your exact job beats any range.
How to read the crack
Direction. Vertical and slightly diagonal cracks in poured concrete are the most common and least worrying. Horizontal cracks are the most concerning, because they usually mean soil is pushing on the wall.
Width. Hairline cracks are typical. Cracks you can fit a coin into, roughly a quarter inch or more, are worth an expert look.
Offset. If one side of the crack sticks out farther than the other, or is higher than the other, the wall has moved.
Change over time. A crack that has not changed in years is very different from one that is growing. Monitoring is the single most useful thing you can do.
Company it keeps. Doors and windows that stick or will not latch, floors that slope, cracks in drywall above door corners, and gaps between walls and ceilings point to movement, not just a crack.
How to monitor a crack
- Mark both ends with a pencil line across the tip, and write the date next to it.
- Measure the widest point with a ruler or a crack width card, and photograph it with the ruler in the frame.
- Check it every few months, and after big seasonal swings like a wet spring or a dry late summer.
- Write down what changed. A crack that grows past its pencil marks, or gets wider, is a reason to call an engineer.
Who to call first
For anything beyond a hairline crack, consider calling an independent structural engineer before a foundation repair company. An engineer charges for an evaluation, commonly $300-$800, and has nothing to sell you. Repair companies often offer free inspections, but their recommendation and their quote come from the same place. Take the engineer's report to two or three repair companies and compare their bids against it.
Fix the water first
Much of what moves foundations is water: soil that swells when wet and shrinks when dry, and water pressure against basement walls. Before paying for structural repairs, make sure water is being sent away from the house.
- Keep gutters clean and downspouts draining several feet from the foundation. See gutter cleaning.
- Make sure soil slopes away from the house, not toward it.
- Avoid letting sprinklers soak the foundation, and keep large trees a sensible distance from it.
- If you have a sump pump, test it before the wet season. See sump pump basics.
When to call a pro
- Any horizontal crack, or a basement wall that bows inward.
- A crack wider than about a quarter inch, or one where one side has shifted.
- A crack that grows past your pencil marks.
- Cracks along with sticking doors, sloping floors, or new drywall cracks above doors and windows.
- Water coming through a crack, especially after every rain.
What makes it worse if you wait
- A wall that is moving usually keeps moving, and bracing a wall early costs far less than rebuilding one.
- A leaking crack brings in water every storm, which can ruin finished basements and feed mold.
- Settlement can crack drywall, tile, and plumbing lines above it, adding repairs that have nothing to do with the foundation itself.
- Unaddressed foundation problems can complicate selling the house, since they often show up in inspections.
Common questions
Are foundation cracks normal?
Thin vertical cracks in poured concrete foundations are very common, usually from the concrete shrinking as it cured. They are not usually structural, though they can leak. Horizontal, wide, offset, or growing cracks are not normal and should be evaluated.
How much does it cost to fix a foundation crack?
Sealing a single non-structural crack often costs $300-$800 with a pro. Structural repairs cost much more: bracing a bowing wall often runs $4,000-$15,000 or more, and piering a settling foundation often runs $1,000-$3,000 per pier.
Should I call a structural engineer or a foundation company?
For anything beyond a hairline crack, an independent structural engineer is often the better first call, since they are paid for an opinion rather than a repair. Use their report to compare quotes from repair companies.
What does a horizontal crack in a basement wall mean?
It usually means soil pressure is pushing the wall inward, which is common in block walls and is the most serious kind of foundation crack. Have it evaluated soon, especially if the wall is bowing or the crack is growing.
Not sure that's your problem? Snap a photo and Berry will tell you what it is and what it should cost.
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