Walls & Painting · Walls
Repair a Hairline Cornice Crack
Repair summary
Hairline cracks at the wall-ceiling join open and close with seasonal movement. Rake the crack out slightly with a utility knife, fill with flexible decorator's caulk, and smooth with a wet finger before painting.
Likely issue
Seasonal movement between wall and ceiling
DIY difficulty
2/5
Estimated DIY cost
$10–$15
Estimated tradie cost
$200–$400
Tools required
- Utility knife
- Caulking gun
- Damp cloth
Materials required
Step-by-step instructions
- Run a utility knife along the crack to widen it slightly.
- Hairline cracks at the wall-ceiling join open and close with seasonal movement. Rake the crack out slightly with a utility knife, fill with flexible decorator's caulk, and smooth with a wet finger before painting.
Safety warnings
If a crack is wider than 3mm or step-shaped, stop — it may indicate structural movement and should be assessed by a builder.
When to call a tradie
Call a licensed tradie if the work is outside the scope of this guide, involves regulated trades (electrical, gas, structural, waterproofing), or if you discover hidden damage. A professional will typically charge $200–$400.
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