Fitting coving and cornices

Summary: Putting up and fixing cornice and coving. Learn how to measure, cut and fit cornice and coving and make a mitre block.

Cornices and coving create an attractive feature between the top of a wall and the ceiling. Coving is a concave length of moulding while a cornice is a more decorative moulding, but the method of fixing is similar for both.

Measuring

From the ceiling measure down the wall the width of the coving - the dimensions should be on the packaging. Repeat along the wall to produce a guideline where the lower edge of the coving will sit.
Taking an off-cut of coving and addressing its lower edge to the guideline, mark another guideline on the ceiling where the coving's top edge will come. To ensure both guidelines are parallel to the walls and ceiling, it's advisable to mark around the whole room before starting to fix the coving into position.
By scratching the wall and ceiling surfaces between the guidelines you will produce a better grip for the adhesive.

Mark guidelines on the wall and ceiling using an offcut.

Fixing

Although there is no right or wrong place at which to start fixing the coving, it is recommended that you start on one of the longer walls, leaving more difficult areas such as chimney breasts until later.

If the wall is longer than your length of coving you will be able to start with a complete length, otherwise measure the wall and cut to size.
To fix the coving to the wall use a Gypsum-based adhesive specially formulated for good ‘grab' and adhesion. Spread the adhesive along the upper and lower edges of the coving and press in place with the edges flush to the guidelines. Wipe away any excess adhesive from the edges.

Long lengths of coving should be supported with panel pins under the lower edge to stop the coving slipping before the adhesive hardens.

Cutting

When two lengths of coving are joined together between two corners they can either be butt-joined or mitred. It is important to support the coving on either side of joint with panel pins.
When joining lengths of coving at a corner you will have to use mitre joints employing a mitre block (see blow) to cut the coving at the correct angle. Depending on whether it is an external or internal corner the coving needs to be cut in a certain direction.
Always check the internal or external corners fit neatly before fixing the coving to the wall.

Finishing

When the adhesive has dried remove all the supporting panel pins and fill the small holes with filler. Then using your finger or a filling knife, fill any small gaps at the internal and external mitre joints.

Making a mitre block

A mitre block can be made quite simply and consists of a baseboard, a fence and a stop batten. The baseboard will represent the ceiling while the fence will represent the wall.

From a piece of 18mm (3/4in) plywood or chipboard cut a baseboard 200mm (8in) wide x 450mm (1ft 6in) long.
Then cut a piece of 100mm x 50mm (4in x 2in) planed softwood to the same length as the baseboard to create the fence.
Take the fence and glue it along one edge of the baseboard.
The stop batten is also fixed to the baseboard. Its position is determined by where the edge of an off-cut piece of cornice or coving comes when addressed to the fence.

Nail the stop batten to the baseboard maintaining an even gap between batten and the fence.
After the glue has dried, make three separate cuts in the fence. The cuts should carry down to the baseboard. One cut should be at right angles to the face of the fence. The other two cuts should be at 45° but in opposite directions and on either side of the first cut. Use a sliding bevel to ensure the angles are accurate.