Plaster coving works like interior moulding trim to provide an extra accent to ordinary walls. The plaster composition allows for intricate patterns that can add a sophisticated touch of beauty. You can add colour to your covings, using paint. Unfortunately, plaster tends to excessively absorb primer and paint. This can lead to hours of painting and repainting, as you attempt to generate an even finish that's free from dull patches. Treat the covings with a special primer made just for plaster, or the finishing process may prove difficult.
Dust your plaster coving with a broom. This is an important step, as dust may make the coving reject primer.
Shield the two areas on either side of the coving from paint overlap. Carefully place painter's tape along these spaces. Run your thumb against the tape to ensure proper adhesion.
Apply a plaster primer to the coving, using a nylon brush. Brush one 90 cm (3 foot) wide area of coving at a time. Dab your brush against any indented design patterns to ensure thorough coverage. Smooth the plaster primer, using the brush. Proceed to your right until the entire strip of coving is primed. Let the plaster primer dry for two hours.
Wash the plaster primer from your brush, using water.
Paint the plaster coving as you primed it. Allow the coving to dry for two hours. Add a second coat of paint.
If your plaster coving doesn't contain any indented design patterns, use a polyester paintbrush. This will encourage a slick finish free from ugly brush marks.
Plaster coving tends to excessively absorb primer and paint. Be sure to use a primer formulated for plaster, or you may have to apply multiple coats.