How to paint cornices and coving: the professional way

Cornices and coving are the ornamental plaster mouldings that run along the top of a wall where it meets the ceiling. In period properties they can be elaborate and heavily detailed; in newer builds they tend to be simpler curved coving. Either way, they are one of the trickier parts of a room to paint well, and a messy coving line is one of the most obvious signs of an inexperienced decorator.

Done properly, painted cornices with clean edges lift the entire look of a room. This guide covers the preparation, tools, and technique that professional decorators use to get a sharp, even finish.

Understanding what you are working with

Before picking up a brush, identify what your coving is made from. Most Victorian and Edwardian cornices are run plaster, which is porous and can absorb paint unevenly if not primed. Post-war coving is often plaster of Paris or expanded polystyrene. The polystyrene type, common in 1970s and 1980s properties, needs careful handling as solvent-based paints can dissolve it.

New coving or sections that have been replaced also need a primer coat before emulsion. Bare plaster or fresh adhesive left visible will cause the finish coat to look flat and patchy in those spots.

Tools you will need

• 25mm or 50mm angled brush (a good quality brush is essential here; cheap brushes leave streak marks in the details)
• Small 1-inch brush for the tightest recesses in ornate cornices
• Masking tape, ideally Frog Tape or similar precision tape
• Fine surface filler and flexible caulk
• 120-grit sandpaper
• White emulsion (standard or specifically a ceiling white)
• A clean damp cloth for any immediate drips

Preparation: the part most people skip

Look along the length of the coving for cracks, gaps where it meets the ceiling or wall, and any loose sections. Use flexible decorator's caulk to fill the joint where the coving meets the wall and the joint where it meets the ceiling. Do not use hard filler here; those joints move as the building settles and hard filler will crack within months.

Apply the caulk with a gun, smooth it with a damp finger, and wipe away the excess with a cloth. Let it dry for at least two hours before painting over it.

For deeper cracks or chips in ornate plaster cornices, use a fine surface filler. Press it into the damage, leave it slightly proud, then sand back once dry. If the original detail has been lost, specialist plaster repair products or pre-made plaster moulding pieces from architectural salvage suppliers can match most common Victorian cornice profiles.

Masking the wall and ceiling lines

If you want a hard line between the coving and the wall colour, apply masking tape along the lower edge of the coving before painting the walls. Leave the tape in place, then remove it carefully after the wall paint has dried.

When you come to paint the coving itself, you have two choices. The first is to freehand the edges using a steady brush technique, which takes practice. The second is to mask the wall and ceiling surfaces and work confidently within the tape lines. Professional decorators with experience usually freehand it, but masking gives a reliable result for anyone less confident with a brush.

Frog Tape is worth the extra cost over standard masking tape for coving work. Its edge-lock adhesive creates a sharper seal against paint bleed, which matters particularly on textured plaster surfaces where cheap tape lifts away and lets paint underneath.

Painting technique for cornices

Start at the top of the coving (the ceiling edge) and work downward. Load the brush moderately, not excessively: too much paint on the brush causes drips into the ceiling, which are awkward to correct without leaving a mark.

For simple curved coving, a 50mm angled brush works well. Hold it at a slight angle and draw it along the length of the moulding in one continuous stroke where possible, rather than short dabbing motions. Short strokes leave visible brush marks in the dried paint.

For ornate cornices with deep recesses, use a smaller brush to get paint into the detail before sweeping the larger brush over the raised areas. Work methodically from one end of the wall to the other, keeping a wet edge throughout.

How many coats?

Cornices that have been painted many times before typically need only one full coat if the underlying colour is similar. Bare plaster or plaster over a significantly different colour will need two coats. Apply each coat thinly rather than thickly; thick paint fills in the fine details of ornate cornices and gradually loses definition over years of repainting.

Between coats, let the paint dry fully. Running a second coat over paint that is still slightly wet on an intricate cornice risks pulling the first coat and leaving patchy areas.

Getting the line between wall and ceiling right

The line where the coving colour meets the wall colour is where the whole job stands or falls. If the coving is white and the walls are coloured, the transition needs to be clean and consistent along the full length of the room.

Work in good light and step back frequently to check the line from a distance. What looks fine up close can show inconsistencies from three metres away. If you are not confident freehanding the line, do not try to do the whole room in one pass. Work in short sections, check each one, and continue.

Once the paint is fully dry, remove any masking tape slowly at a 45-degree angle. If the tape pulls away any paint, use a small brush to touch up immediately while you have the correct paint and brush to hand.