Ceiling joists are usually not close enough to a plaster ceiling surface to accommodate screws. If you want to hang a plant or attach a fixture to the ceiling, you'll have to screw directly into the plaster. This will hold for a little while, but the plaster degrades over time and the screws fall out. Fortunately, you can fix faulty screws in ceiling plaster with just a few basic tools.
Position an a-frame ladder underneath the ceiling screws.
Climb the ladder.
Unscrew the existing screws if they have not completely fallen out yet.
Chip off loose plaster using a putty knife. If you try to place your plaster patch over cracking or loose plaster, it will just fall off. You must chip off existing damage before you make repairs.
Blow compressed air into the damaged plaster. This removes excess dust for easier patching.
Slather plaster patching compound on the damaged area, working it into the hole.
Smooth out the plaster patching compound with a putty knife. Wait for the plaster to dry before continuing. Quick-drying patching compounds are dry in 15 minutes. Others must sit overnight.
Sand the plaster patch smooth with 300-grit sandpaper.
Wipe away sandpaper dust with a damp rag.
Paint the plaster with a synthetic-bristle paintbrush and latex paint to match the ceiling. Wait for the paint to dry before proceeding. Most latex paint is dry in one or two hours.
Place a wall plug on the end of a screw. Wall plugs are little pieces of plastic that expand as you screw them into a wall or ceiling. They are sold at most hardware stores. Wall plugs create a more stable surface when used in plaster.
Drive the wall plug and the screw into the ceiling using a Philips or flathead screwdriver, turning clockwise.