Repairing the Ceiling Where It's Separating

Remove furniture from the room, or push heavy pieces to the middle and cover them with tarp. Spread drop cloths on the floor to collect residue. Set a sturdy stepladder directly under the ceiling crack. Wear a facemask and protective eyeglasses before climbing the ladder.

Scrape off the loose pieces of drywall and plaster from the area of the crack using a putty knife. Continue to scrape off plaster to reveal the mesh or paper tape underneath. Pull off the tape to expose the seam or separation between the two pieces of drywall.

Cut a length of mesh drywall tape and lay it over the seam, covering it completely. Press the tape over the seam, working outward from the center, to remove bubbles.

Spread a thin layer of drywall joint compound over and along the tape using a drywall knife. Ensure the line of compound is slightly wider than the edges of the tape. Smooth the line of compound with the knife to knock out any bumps, so it falls flat and smooth against the surrounding surface. Allow the joint compound to dry for 8 to 10 hours.

Lightly sand the surface of the dried compound to score it and flatten the tiny bumps you left earlier. Apply another layer of compound over it, keeping it slightly wider and thinner than the previous layer. Allow this coat of compound to dry for 8 to 10 hours.

Scrape off or sand high spots in the compound when it cures. Continue to apply another layer of compound over the seam, keeping it flatter and wider than before. Let the layer dry for 8 to 10 hours.

Sand the cured drywall compound using a drywall sander, prime the repaired section and paint over it, so it blends with the surrounding ceiling surface.