Ceiling cracks look worrying, but most are harmless. They usually come from movement, temperature changes, or old plaster.
Common causes
- Natural settling
- Humidity changes
- Poor plaster adhesion
- Structural movement (rare)
1. Natural settling
Homes shift slightly over time.
Quick fixes:
- Fill hairline cracks with flexible filler
- Repaint with ceiling paint
2. Humidity changes
Bathrooms and kitchens are common trouble spots.
Quick fixes:
- Improve ventilation
- Use extractor fans
- Apply mould‑resistant paint
3. Poor plaster adhesion
Old plaster can separate from the ceiling.
Quick fixes:
- Tap the area — hollow sounds mean loose plaster
- Patch small areas with filler
- Larger areas may need re‑skimming
4. Structural movement
Wide cracks or sagging can indicate a bigger issue.
Quick fixes:
- Photograph the crack and monitor it
- Check for leaks above the ceiling
What to try first
Check for leaks — water damage is the only urgent cause.
When to call a professional
If cracks are wider than 5mm or the ceiling sags.