How to cut internal mitres using a cove mitre?

28th February 2020


How to cut internal mitres using a cove mitre


	Shop for Cove Mitres


		To accurately cut mitres for the corners of your coving and fit them to the room you will need a few other tools apart from your cove mitre.

		Other tools needed
		The other tools you will need are a pencil, tape measure, fine tooth saw (such as a tenon saw), sponge, bucket (a second bucket may be required), hammer, panel pins, stripping knife, utility knife, fine grit sand paper and coving adhesive.

		Preparation
		Step 1 – Cut template Using the fine tooth saw, cut a 150mm (6″) section of coving to use as a template.

		Step 2 – Mark coving position Position the template you have just cut so it sits where the ceiling and wall meet. Using a pencil, mark along the top edge of the template onto the ceiling and along the bottom edge onto the wall.

		Repeat this step every 600mm (24″) along the wall. This will act as a guide, helping to ensure that the coving does not droop as you fix it in place along the wall.

		Step 3 – Prepare wall and ceiling If the walls and ceiling have been recently plastered you will need to run a damp sponge along them to moisten the surface. This will prevent them from drying out the coving adhesive too quickly, which would result in it not sticking firmly.

		Many people like to lightly score (key) the surface of the walls with a utility knife where the coving will be stuck. This will give a better surface for the adhesive to stick to, holding the coving more firmly in place.

		Step 4 – Determine type of cut There are four types of cut you can use a cove mitre for: left- and right-hand internal mitres and left- and right-hand external mitres.

		A right- or left-hand mitre is taken from the point of view of the coving, as if you were looking into the room from the outside, not from your viewpoint looking at the wall!

		How to cut an internal mitre
		For ease of description and to avoid confusion, the following guide is given with a right-handed user in mind. A left-handed user would have to stand the other side of the coving.

		Step 1 – Place coving on secure surface Place the coving on a secure surface for sawing which will support its entire length, less the waste section to be cut off. The coving should be laid on its flat back side with the concave (curved side) facing up, and the wall edge of the coving closest to you.

		Step 2 – Position the cove mitre If you are cutting a left-hand internal mitre, you should position the cove mitre so that its left-hand face is at the far left end of the coving to minimise the waste.

		If you are cutting a right-hand internal mitre then you should position the cove mitre so that its right-hand face is at the far right end of the coving to minimise the waste.

		The cove mitre should rest across the coving with either the plastic lip or the notches holding it in place on the wall edge of the coving.

		Step 3 – Cut mitre Holding the saw in your dominant hand, place the saw on the left-hand side of the cove mitre face for cutting a left-hand internal mitre, or right-hand side of the face for cutting a right-hand mitre, so that the saw’s blade rests against the edge of the cove mitre.

		If you are cutting an internal left-hand mitre, you may find it easier to stand on the the other side of the coving to make the cut.

		Tilt the saw so that the blade rests flat against the angled surface of the cove mitre. This may be more difficult with the curved plastic type as the faces are really quite narrow edges, although they are angled in the same way. Hold the cove mitre in place on the coving with your non-dominant hand and use smooth, steady strokes of the saw to cut the coving.

		How to fix coving in place
		Step 1 – Check coving length Having cut the first mitre joint at the end of the coving, offer up the coving to the wall. If the coving is longer than the wall, cut the coving to approximately half the wall length – the joint can be easily hidden later.

		Step 2 – Mix adhesive If you are using a powdered coving adhesive, follow the instructions provided and mix it with the right amount of water in one of the buckets. You can also get ready-to-use coving adhesive, but this can work out more expensive if you have a lot of coving to put up – although it will save time.

		Replace the cap on ready-to-use adhesive after applying it to a section of coving to prevent the remaining adhesive from setting prematurely.

		Step 3 – Apply adhesive Apply plenty of the adhesive to the back of the coving using the scraping knife.



		Step 4 – Push into place Push the coving into place on the wall and ceiling. Use the pencil marks made earlier with the template to ensure that the coving does not droop down.

		Step 5 – Secure with nails Using the hammer, knock some small nails or panel pins into the wall just under the edge of the coving. These will hold the coving in place while the adhesive sets, allowing you to cut and fit the rest of the coving.

		Step 6 – Remove excess adhesive Using the scraping knife, remove any excess adhesive. Run a damp sponge along the two edges of the coving to smooth out the remaining adhesive.

		Step 7 – Mark second length of coving Take a piece of coving with the mitre cut for the other end of the first wall. Offer it up to the wall and mark the point at which it overlaps the first piece of coving you have already put up.

		If it’s too long to offer up to the wall, measure the distance from the non-mitred cut end of the first piece of coving to the corner of the wall. Mark this distance along the wall edge of the second piece of coving from the mitre joint you have already cut.



		Step 8 – Cut to length Cut the second piece of coving to length, removing the overlap.

		Before fixing the coving to the wall, placing a slight chamfer on the cut edges with fine sandpaper will help you create a better joint with filler or adhesive later on.

		Step 9 – Fix second piece in place Repeat steps 3-6 with the second piece of coving.

		Step 10 – Measure gap If you have a gap between your first two pieces of coving, measure the gap between them. Mark this measurement onto a third piece of coving from a non-mitred end.

		Step 11 – Cut infill section Cut this to length. This cut should be a 90-degree cut, not a mitre. Use a try square or combination square to make sure this is done accurately.

		Step 12 – Fix infill section in place Repeat steps 3-6 with the infill section of coving. Place a little adhesive on the ends of the piece before pushing it into place.

		Step 13 – Fill and smooth gaps Using a scraping knife or your finger, fill any gaps with adhesive or filler. Wipe over the areas you have filled with a damp sponge to smooth the joins.

		Step 14 – Fit coving to other walls Repeat steps 1-13 for each of the other walls. For fitting coving to a room’s external corners see How to cut external mitres using a cove mitre. Once all the coving has been fitted allow plenty of time for the adhesive to set (see adhesive instructions for approximate setting time).

		Step 15 – Remove nails Once the adhesive has dried, remove the nails from the walls and fill any holes with filler.

		Step 16 – Smooth with sandpaper If any of the joints between the pieces of coving are rough, these can now be sanded smooth with a fine grit sandpaper. Re-fill as required and sand down once dry, repeating until a satisfactory finish is achieve, after which the room and coving will be ready for painting.