Putting up cornice or coving

Adding cornice

Cornice can add the finishing touch that makes a room look complete and it requires no special skills to put up. The description cove or cornice both tend to be uded in diy.

Types and prices

Cornicing comes in three basic types: polystyrene, paper covered gypsum and plaster. It comes in a limited number of widths and there are some embossed swag and floral patterns as well.
Polystyrene coving must be painted with emulsion and is easily damaged.
Paper covered gypsum cornice is slightly heavier but the smooth paper covering gives a much better base for painting.
Plaster coving is the most expensive option. Although it is a brilliant white, smooth finish that needs no painting, unless you are really proficient with mitreing the corners and able to keep your hands very clean, you'll find a couple of coats of emulsion won't go amiss.

A new lightweight product from SuperCove is also available. This super-light coving was voted Top Product in Category by Professional Builder Magazine. It is made from polyurethane with a high quality paper face and is incredibly easy to work with.

Fixing cove

Cut off a small 100mm length of cornice to use as a template. Use this piece to mark the top and bottom edges of the cornice on the walls and ceiling all around the room. Make the marks at regular intervals so that you can join them with a straight edge.

Connect the marks with a straight edge (the edge of a spirit level is ideal) and remove any wallpaper or loose paint and plaster from the area. Make criss-cross scratches between the guide lines with a craft knife to provide a key for the adhesive.

Cutting angles

Use a mitre box to help cut an accurate mitre at the end of the first piece of coving. Take care to place the cornice the right way around and always double check that you are cutting the angle in the correct direction.

If your wall length is less than that of a piece of the cornice, you will need to accurately measure the wall and cut the other end with an appropriate mitre as well. This will normally be the reverse angle. When making the cuts, use a fine-toothed saw, and sand the edges smooth with some sandpaper. Take your time with the mitres as the neater you do these, the less work you will have later on.

With a filling knife, spread an even layer of adhesive over the top and bottom of the back of the moulding - the areas that will be in contact with the walls and ceiling.

Press the cornice into place and line up the bottom edge with the pencil guide line. Press gently along the whole length so that the adhesive sticks evenly.

Supporting the coving

Long lengths of coving may sag or fall off before the adhesive has set. Temporarily support the bottom edge with one or two galvanised nails. You can remove these and fill the holes when the adhesive has dried. Depending on the type of cornice, you might also find it beneficial to put a couple of these nails in the ceiling as well to stop the cornice rolling forward.

Use a damp paintbrush to remove any adhesive that oozes out from the top and bottom edges and to smooth the joint line. Fill any gaps with more adhesive.

Continuing around the room, you can simply butt one piece up to the previous one with a straight join. Often, however, a neater, less obvious joint can be produced by 'splicing' the two. To do this, you will need to mitre the end of the first piece before fixing in place. With the second piece, simply cut the same mitre at the beginning of the length. This second piece will either be a full length, in which case you will need to repeat the joining process, or cut to size at a corner, in which case it will need to be mitred accordingly.

External corners

If you have any 'external' corners in the room, you will need to cut the two ends which join here with mitres in the opposite direction. This often causes problems since, not only have you got to remember to cut the angle the right way, but also the point to which you measure is different. The best way to remember and get it right is to always measure for the bottom edge of the cornice on external angles and the top edge for internal angles.

If your walls are slightly bowed you can still add cornice as the plaster is flexible enough to be slightly curved to match the wall. However, to keep it in place you should plug and screw it to the wall with brass screws. Countersink the heads and fill the holes with a dab of adhesive. Don't use steel screws as these will rust and discolour the surface. At the same time, make a note in which direction the angle should be cut.

Try to make as few joints on the walls as possible. It's worth buying an extra full-length piece of cornice rather than use up two shorter sections - the result will be neater.

Fixing heavy cornice

Very heavy plaster cornice may need to be fixed with brass screws at 1m spacings to provide adequate support. Hold the cornice in position and drill carefully through the cornice and into the wall. Add wall plugs, spread on the adhesive and screw into place.

Most plaster type cornice is fairly fragile so take care when lifting it so that it doesn't snap. Get the help of an assistant, particularly with the heavier plaster type.

It is always best to work from a platform rather than simply on a stepladder. Set up a safe and stable working platform using two pairs of steps or hop-ups and a suitable scaffold board. Be sure that the board is properly supported and strong enough to take your weight. This will enable you to concentrate on fixing the cornice, rather than having to continually move your steps.

Repairing old cornice

If you are lucky enough to have original coving, you can remove clogged paint with a chemical stripper. Cover the floor with plenty of paper and wear safety goggles and gloves. Dab on the stripper with a brush and work well into any mouldings. Leave to work and then remove the paint with a nylon scouring pad and an old screwdriver. Take care not to damage the plasterwork. Fill any cracks with a plaster filler. If you're patient, you can also re-build any small missing details as well.

• Wall fixings
• Plastering
• Painting walls