Foundation Warning Signs: What They Mean and What to Do
Not every crack is a crisis. This page lists the signs we get called about most, tells you honestly how worried to be, and points you to the page that explains each one.
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Use the labels as a rough guide. Usually minor means keep an eye on it. Worth a look means have someone check it this season. Call soon means it can get worse or more expensive if you wait.
Every house is different, and a photo or a visit beats a guess. If you are not sure, order an inspection or ask for a free estimate.
Signs in your basement walls
Thin vertical crack in a poured wall
Usually minorHairline vertical cracks are common as concrete cures. Watch for leaking or a crack getting wider.
Stair-step cracks in block or brick
Worth a lookCracks that follow the mortar joints in a stair pattern can mean settling or pressure from the soil outside.
A wall bowing or leaning inward
Call soonA horizontal crack or a wall that bulges in is soil pressure pushing on the wall. It tends to get worse.
Wall sliding in at the bottom or top
Call soonWhen the top or bottom of a block wall shifts inward relative to the rest, the wall is shearing.
Crumbling mortar or loose stones
Worth a lookOld stone and brick foundations lose mortar over time. Very fixable when caught early.
Signs of water getting in
Water at the joint where wall meets floor
Worth a lookThe most common basement leak. Usually groundwater pressure, not a broken wall.
Damp walls but no puddles
Usually minorCould be water coming through, or just humid air condensing on cool walls. The fix is very different.
White powder or crust on the walls
Usually minorThat is efflorescence, minerals left behind by water moving through the masonry.
Musty smell or mold
Worth a lookMoisture is getting in or staying in. Find the source before you treat the mold.
Water coming in at a basement window
Worth a lookUsually a window well that does not drain or fills with runoff.
Sump pump running constantly, or not at all
Call soonA pump that never stops or never starts is a warning before a wet basement.
Signs in your floors and the rest of the house
Sagging or bouncy floors
Worth a lookUsually the wood framing under the floor, like tired joists, beams or posts, not the foundation itself.
Doors or windows that stick, and new drywall cracks
Worth a lookCan be seasonal, or a sign that part of the house is settling.
Basement floor heaving or cracking up
Worth a lookOften frost or water under the slab pushing up.
Cracked garage walls or floor
Usually minorGarages often move separately from the house and show problems first.
Damage you think might be termites
Worth a lookTermite damage and foundation movement can look alike. Worth telling apart before you pay for either fix.
Signs around the outside of the house
Water pooling next to the foundation
Worth a lookThe ground should slope away. Pooling water is the start of most basement leaks.
Leaning or cracked retaining wall
Worth a lookA failing retaining wall can push on the house or dump water toward it.
Chimney pulling away or cracking
Worth a lookChimneys have their own footing and can move separately from the house.
Damage after a big storm
Worth a lookHigh winds and uprooted trees can damage foundations and drainage.
Not sure what you are looking at?
Tell us what you see. A working contractor, not a salesperson, will give you a straight answer and a written estimate.