Start with the crack’s position

If the crack tracks one edge of the outside corner, the bead or its compound may be the local failure. If it crosses the corner, opens and closes with movement, or continues across the wall, treat it as a wider movement question. Brown staining, soft board, or a musty smell moves moisture to the front of the queue.

A simple decision tree

  1. Photograph the corner in side light and mark the ends of the crack.
  2. Press gently beside the crack. Stop if the board flexes, crumbles, or feels damp.
  3. Tap the area and compare it with a sound section of the same corner.
  4. Check whether doors, trim, or nearby joints show new movement.
  5. Repair only when the bead and wall are dry, firm, and stable.

For a stable local failure, remove loose compound, secure or replace the damaged bead only as the system instructions allow, then rebuild thin coats and feather the edges. Do not create a hard hump by filling the whole corner in one pass.

Identify the bead before choosing a repair

A hollow sound or small amount of flex is an observation, not proof that the framing has moved or that adding a screw is the solution. Compare the crack with an undamaged part of the same corner and record whether an impact, moisture event or earlier patch preceded it.

Beads are not all fastened alike. USG’s paper-faced metal bead documentation includes tape-on styles that embed in compound without nails. A repair suitable for mechanically attached bare metal may damage that system. Establish the bead type, whether its edge bond has failed, and whether the nose is bent before choosing re-embedding, fastening or replacement. Follow the matched compound and bead instructions for coats and drying.

Before scraping or sanding a painted corner in a pre-1978 U.S. home, check the lead-paint risk. EPA recommends lead-safe assessment and work practices , including using a certified contractor where appropriate. A small cosmetic patch can still release hazardous dust. Do not start by dry-sanding an unknown old coating.

When to stop

Stop cosmetic work if the crack returns, the wall is damp, the corner is distorted, the damage follows a ceiling or opening, or you suspect structural movement. A corner can be the visible end of a problem that needs inspection elsewhere.

Limits

No corner was inspected and no universal repair material or drying schedule is prescribed. Product instructions, moisture control, and qualified local advice control the actual repair.