Why stump homes crack
A house on stumps is carried by dozens of individual posts, each bearing on the soil below. When a few stumps rot, split or sink into softened clay, that section of the house drops a few millimetres — and the plaster or brickwork above it cracks as the frame twists.
The pattern matters more than the crack itself. Movement cracks tend to appear near the corners of doors and windows, run diagonally, and come with friends: a floor that's off level, a door that suddenly sticks.
A crack that has appeared or widened noticeably within weeks — especially one wider than 5 mm — deserves a professional inspection soon. It's rarely an emergency, but movement that fast means something under the house has changed.
Reading crack width
Engineers classify cracks by width. As a homeowner rule of thumb, anything you can fit a 5-cent coin edge into deserves attention.
Where the cracks are tells you a lot
On stump homes, cracks cluster where the frame flexes:
- Above doors and windows — the classic spot; openings are the weakest point in a wall.
- At cornices and ceiling joins — the frame pulling away as one side drops.
- Along one side of the house only — often a drainage problem softening soil on that side.
- External brick veneer stepping along mortar lines — the veneer following the footing down.
Other signs to check while you're at it
Cracks alone rarely settle the question. Walk the house and check the usual companions: sloping or uneven floors, doors and windows that stick, and soft or bouncy floorboards. Two or more together strengthens the case that stumps are the cause.
What to do next
Photograph each crack next to a ruler or coin, write the date on the photo, and re-check in a month. If cracks are growing — or already past 5 mm — get an inspection from a restumping contractor or building inspector. Quotes for inspection and restumping are typically free. See what restumping costs and how to choose a contractor.
Get a professional's eyes on it
Free inspection quotes from licensed restumping firms near you. No obligation.
Common questions
Should I fill the cracks or leave them?
Leave them until the cause is settled. A filled crack hides the evidence an inspector needs — and if the house is still moving, it will simply crack again.
Can one bad stump really crack a wall?
Yes. Each stump carries a share of the load; when one fails, the bearers span further than they were designed to, and the frame above flexes. That's also why partial restumping is sometimes all a house needs.
Will insurance cover the damage?
Usually not for gradual movement or rot, which insurers treat as maintenance. There are exceptions — burst pipes, sudden events. Read the insurance guide before assuming either way.