Symptoms
- Vertical crack running along where two walls meet
- Crack may open and close slightly with seasons
- Paint or tape visibly separating at the corner
Likely causes
- CommonTape flexing at a natural stress pointInside corners move slightly as the house settles, which can crack the tape joint there.
- CommonTape not embedded well during original finishingIf the tape wasn't pressed in firmly, it's more prone to separating later.
- PossibleHouse framing shifting seasonallyHumidity changes cause minor movement that repeatedly stresses corner joints.
What to do
- Check whether the crack opens and closes with the seasons, which is usually harmless.
- Cut back any loose or bubbled tape with a utility knife.
- Apply new paper or mesh tape into the corner, pressing firmly with a corner tool.
- Cover with a thin layer of joint compound on each side.
- Let dry, sand lightly, and apply a second coat if needed.
- Prime the repaired corner before painting.
- Repaint to match the surrounding walls.
Tools and parts
- Utility knife
- Corner taping knife
- Sandpaper
Drywall corner tapeSearch: “paper drywall tape for inside corners”
When to call a pro
Call a drywall finisher if the crack keeps returning after repair, since it may need a more flexible caulk-based fix instead.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.