Foundation · triage
Foundation and drywall cracks: which to worry about
The short answer
Thin hairline cracks that don’t change are common in drywall and concrete. Cracks wider than about 1/4 inch, cracks that grow, stair-step cracks in block, or new sticking doors and sloping floors: get a structural engineer’s opinion.
Sudden movement is differentCracking sounds, a wall that moved or a sagging ceiling: use the structural-movement card and get people clear.
Every outcome on this card
Emergency nowPossible structural movement
Get clear, then call.
- Get people away from the area
- After a quake or storm, check for gas smell; leave if you smell it
- Call a structural engineer or your building department
This monthGet an engineer’s opinion
Book an independent structural engineer this month.
- Measure and photograph each crack with a ruler and date
- Mark crack ends in pencil to see if they grow
- Hire an independent engineer before a repair company An engineer’s report tells you what is needed; then get repair quotes against it.
Soil movement, drainage and expansive clay are common causes. Fixing drainage is often part of the answer.
WatchMonitor it
Watch, measure, log.
- Mark the crack ends and date them
- Photograph with a ruler every few months
- Keep gutters and grading directing water away
Shrinkage and settling cracks are common, especially in the first years of a house.
Related
Written from
Original casaq guidance, updated 2026-10-05. General guidance, not a diagnosis; licensed-pro review pending. Severity levels: Emergency now / Today / This week / This month / Watch. Send a correction.
Step 1