Cracks in Ceiling: When to Worry
Most ceiling cracks are cosmetic: drywall seams, paint and normal house movement. A few signs mean you should act fast.
Act now if: the ceiling is sagging or bulging, the crack runs along a sag, there's a water stain or drip, or a crack appears suddenly with cracking sounds. Keep people out of the room and get a contractor or structural engineer to look at it.
Common ceiling cracks
When to worry about ceiling cracks
| You see | Likely cause | Concern |
|---|---|---|
| Hairline crack, no other signs | Settling, paint, seasonal movement | Low: monitor or patch |
| Straight crack along a seam | Drywall joint movement | Low: re-tape |
| Crack where wall meets ceiling | Truss uplift | Low: flexible caulk or molding |
| Crack with yellow or brown stain | Roof or plumbing leak | Medium: fix the leak first |
| Wide crack (over 1/8") or several new cracks | Framing or foundation movement | Medium to high: inspection |
| Crack with sagging or bowing | Failing ceiling material, overloading or framing problem | High: act now |
Cracks in drywall ceilings vs. plaster ceilings
Drywall ceilings usually crack along joints, so you'll see straight lines at regular spacing, often 4 feet apart. Plaster ceilings in older homes crack in random or spiderweb patterns as the plaster ages. That's normal, unless the plaster sags, which means its "keys" have broken from the lath above.
How to fix a crack in the ceiling
- Check for water first. Repairing over an active leak wastes the repair.
- Scrape off loose paint and texture, and open the crack slightly with a utility knife.
- Apply mesh tape over the crack, or paper tape bedded in compound for joint cracks.
- Apply two or three thin coats of joint compound, feathering wider each time. A setting-type compound shrinks less.
- Sand, prime with a stain-blocking primer if there was water staining, then repaint. Match any texture with spray or roller texture.
For cracks at the wall-ceiling joint that keep coming back, fill them with paintable flexible caulk instead of compound, or install crown molding nailed only to the ceiling.