Ghost joint
A ghost joint is the outline of a plasterboard joint showing through the finished paint. Caused by painting before compound has fully cured or by insufficient sanding.
Ask Chalkline about this →A ghost joint is the faint but visible outline of a plasterboard joint showing through the painted surface, usually under raking light or once the room is in normal use. The joint pattern (tape outline, screw line, or butt-joint band) telegraphs through one or more coats of paint and is not corrected by simply painting again.
Common causes:
- Paint applied before joint compound was fully cured (residual moisture creates a sheen and shrinkage difference)
- Insufficient sanding, leaving a perceptible ridge that catches light differently
- Sanding through to the paper face on one side of the joint, creating a sheen mismatch
- Butt joints not back-blocked on a critical-light wall
- Wrong finish level specified for the lighting condition (Level 4 where Level 5 was needed)
The fix is rarely just another paint coat. It usually means re-skimming the affected joint, re-sanding, sealing the patched area, then repainting. Ghost joints commonly appear at PCI and during the first six months as the building dries down.
Category: Defects.