Plaster ceilings can transform the look of a room. Plaster can be applied to raw drywall as the finish coat, or it can be applied to a previously-painted ceiling for a custom effect. The beauty of a plaster ceiling is that it can hide a multitude of defects, does not require any previous experience and can be completed in a day. Although applying plaster can be a sloppy endeavour, the messes are easily cleaned with soap and water.
Cover the floor, wall-to-wall, with the dust sheet. Cover any furniture in the room.
Check that the ceiling is smooth, and remove anything hanging from the ceiling.
If the ceiling had been previously painted with a gloss paint, go over it with the sandpaper to roughen it slightly. Wipe it down afterwards with a damp rag.
Tape off the walls at the point where they meet the ceiling. The top of the tape should end at the top of the wall. This will keep plaster off your walls, and speed up cleaning time.
Put on the goggles. Prepare the pre-mixed plaster according to the manufacturer's directions. Most pre-mixed plasters need to be stirred before using to mix any ingredients that had separated during storage.
Using the putty knife, transfer some of the pre-mixed plaster onto the hand-held hawk. A hawk is a square piece of metal with a handle on the bottom. This will make it easier to handle the plaster while on the ladder.
Starting at a corner of the room, scoop up some of the plaster with the drywall trowel. Apply to the ceiling, pushing it on with the drywall trowel. Cover only about a 3x3-foot area, but leave the edges random. You don't want your start-stop areas to be noticeable. Apply a fairly even coat of about 1/4 inch. Scoop up more plaster, and apply it over the fresh plaster, working it into a pattern or design. It is easiest to use a random pattern. The thicker you apply the plaster, the longer it will take for it to set. That gives you a little more time to go back and work your design. Refill your hawk with more plaster as needed.
Continue in sections until the ceiling is done. Using fresh plaster, go back over any areas that look uneven. Let the plaster dry for a couple of hours before removing the tape.
A smooth, flat, flaw-free finish is almost impossible for a non-professional to achieve. A thicker finish with a design is much easier. Before starting the project, practice applying plaster and working the designs on a scrap piece of wood or drywall. Special "textured" trowels are available that make designs in the plaster.