Painting a plaster ceiling, whether several decades old or newly installed, requires several steps. The texture of the ceilings can vary from smooth to rough. Ceilings should always be painted before any other surface is painted in the room, including walls and trim.
Repair any cracks to the ceiling prior to painting. Remove all dust and cobwebs using a vacuum cleaner and damp rags. Fill any holes or gaps with caulking.
Remove all furniture from the room if possible. Cover all remaining areas in the room, including window treatments and flooring, with drop cloths as plastic sheets.
Choose a high quality latex paint. Look for a 100 per cent acrylic paint. Not all acrylic paints are full acrylic, and some can contain additional additives and chemicals that may not adhere to a plaster ceiling. To be considered 100 per cent acrylic, the can's label must specifically have that printed on it. Brands such as Home Depot's Behr and Lowe's Valspar are full acrylic paints.
Tape off edges using painter's tape (often coloured blue). Burnish the edges and make sure there are no gaps into which paint can seep. Wood trim and light fixtures may also need to be taped off.
Prime the ceiling using an alkaline-resistant primer. The primer will allow the latex paint to adhere to the plaster ceiling. The primer prevents alkaline in the plaster from seeping through to the layer of paint. If not sealed properly, the paint can peel as well as fade. Priming and painting will follow the same techniques.
Cut into the perimeter of the ceiling and work around the edges. Dip an angled brush slightly into paint. Glide the brush along the edge of the ceiling, using the tip of the brush to make a straight line. The brush will fan out, allowing the tip to form a straight line. This technique is referred to by painters as "cutting in." Leave a 3- to 4-inch-wide band of paint. Use a 3-inch synthetic bristle brush that has an angle and is made for trim work. If the plaster is heavily textured, it may be necessary to pounce in with a second brush to get all the grooves and nooks of the plaster painted. A second or even third coat may be necessary depending on the colour.
Roll the paint in sections. Use a roller with the appropriate nap. If the plaster has a very rough texture, a 3/4-inch nap roller is recommended. For smooth plaster walls use a 1/2-inch nap roller. Attach the roller to a painting pole for additional ease and control over the paint area. Roll in long strokes, applying even pressure. Apply a second coat if necessary.
Remember to take breaks. Painting plaster ceilings can cause additional strain to neck and back muscles.
Remove all tape. Pull the tape off slowly. If there is resistance, use a razor knife to lightly cut the tape off. Cautiously remove all drop cloths and plastic---paint can easily drip from plaster ceilings and remain wet on the protective sheets.
Painting a ceiling requires substantial work from high areas. Always use stable ladders and scaffolding. Do not overreach and throw yourself off balance.