Repair a Recurring Ceiling Crack With Fiber Tape and Two Coats

The Problem

Some ceiling cracks come back. Fill a movement crack — the kind that runs off a corner and opens and closes with the seasons — with plain filler, and the next humidity cycle telegraphs it straight back through the paint. Filler has no tensile strength; the crack needs something spanning it that does.

The Technique

This painter's repair on a corner movement crack:

1. Clean down the crack — brush out dust and any loose material so the compound has something to grip.
2. Mix a setting-type base compound (his sets in 45 minutes) and lay a thin bed of it over the crack.
3. Cut paper-thin fiberglass mesh — FibaFuse-type, not the sticky-back window-screen mesh — to length, and bed it into the wet compound over the crack line.
4. Coat over the top of the mesh with more base compound, keeping it thin; the mesh should be buried, not floating on a mound.
5. Once set, float a sandable finishing compound over the repair — and take this coat out well wider than the mesh on both sides, feathering the hump into the ceiling plane.
6. Sand smooth, then paint the ceiling.

The mesh is the actual repair: it gives the joint tensile reinforcement across the crack, so seasonal movement is distributed through the taped zone instead of concentrating at a hairline.