Remove any damaged sections of the bubble or popcorn ceiling with a putty knife. Scrape to remove loose paint by slipping underneath the paint. Scrape all around so that the ceiling is left flat and smooth.
Clean the area. Remove debris, dust and grime. Using a cleaning solution, if needed. Then wait for any moisture to dry.
Apply shellac-based primer-sealer or an alkyd wall primer to the damaged areas. Let the sealer dry completely. Shellac-based primer will take an hour to dry, while the alkyd wall primer will take about 24 hours to dry. Open windows or have open ventilation to circulate air and expedite the drying process.
Apply thin layers of joint compound with a joint knife to any areas of the surface that are cracked, has holes or is depressed. Apply a skim coat of the compound and scrape away excess with the joint knife to leave the surface smooth and even. Let the compound dry.
Smooth out the ceiling further with a joint knife and sandpaper. Use medium or coarse sand paper. Clean off excess dust with a wet rag.
Finish the ceiling by applying the primer-sealer again. Let it dry.
Prepare the area. Place a drop cloth on the floor and wear a mask, goggles, gloves and protective clothing because the paint can drip and splatter onto the floor.
Mix paint in a large bucket to reach the consistency of porridge. Follow mixing directions on the container. Paint for popcorn or textured ceilings already comes ready-mixed with "popcorn" texture.
Fill the hopper sprayer with the paint mixture. Test the sprayer and paint onto a piece of cardboard to become familiar with the controller.
Spray lightly onto the ceiling that needs to be repainted. Avoid over-saturating areas with paint so it won't drip onto the floor. Use several layers of light spray, allowing time to dry between coats.