How to fit coving for beginners
This guide is for DIYers who want to fit basic Gyproc paper covered coving. This is not recommended for heavier higher quality ornate plaster coving, which requires extra mechanical fixing.
- Coving mitre tool
- Coving adhesive
- Tape measure
- Hammer – small if possible
- Panel pins
- Filling knife
- Wiping in brush
- Steps – 2 sets if possible
How much coving do I need
Measure the length of each wall in your room, take the sum of this total and add 10% to allow for wastage.
Preparing the walls and ceiling
You need to create lines on the wall and ceiling that will act as a guide and keep your coving in line when you work around the room. To do this, you will need a template. Saw a small section of the coving that you will be using, a twenty centimetre length will be perfect. Take this template and present it squarely to the wall and ceiling. Whilst holding the template in place, mark a line along the top side which is against the ceiling and also the bottom line which is against the wall. Do this at roughly sixty centimetre intervals all the way around the room.
Cutting your first corner
The next step is to cut two pieces of coving for your first corner. There are differing opinions on which corner you should start in. If you are new to DIY and are quite nervous about installing, then maybe you want to start in the least visible corner of your room, so if you do make a small mistake then it won’t be as obvious. This also give you time to practice so when you do reach the most prominent area, you would have had more practice and confidence. On the other hand professionals will always start in the most prominent corner because it’s easier to get the two mitres to line up.
Cutting the miters
Coving lengths normally come in 2.4 or 3 metre lengths, most rooms have walls longer than these lengths so normally when you start you only need to worry about sawing a mitre from two full lengths.
Use a mitre tool
A corner is basically a mirror image of the two walls that meet there, so you will need a left hand mitre and a right hand mitre. The best way to cut these mitres is with a special but low cost tool (less than a tenner) called a cove mitre tool. This tool is great because it allows the beginner to cut the cornice flat on the ground and face on, one of the reasons cutting mitres can be confusing with a normal mitre box, is because the user has to cut the plaster mould at hard to grasp angles.
Put a mark on each piece
Cut your two angles and then make a small pencil mark on each section to remind you which piece is for which corner, it never hurts to hold them in place first to make sure you have cut the correct angles. You should now have two pieces of coving marked up and ready for the next stage. More experienced plaster moulding installers will normally cut more, but as you are a beginner its best to break the job down into smaller, more manageable chunks.
You have two options when it comes to adhesive – pre mixed or powdered adhesive that you need to mix yourself. The pros of pre mixed are that it’s easier to apply and you can also get premixed plaster adhesive in a handy gun applicator. The down side is that it usually costs more than powdered. Most of the people who are installing themselves cannot afford to pay someone or are on a very tight budget, so mixing your own will save you some pennies. Because the adhesive will dry out pretty quickly, you need to mix it just before you fix the coving to the wall, so now is the time to do that.
Mixing coving adhesive
When mixing up the adhesive be sure to wear a mask, it is surprising how much dust can fill the room when pouring powdered adhesive into the water. Be sure to slowly lift the adhesive out of the bag with a trowel and place the powder into a bucket with a small amount of water in. It is best to start with a small amount of water because you may end up mixing more than you need, if this is your first time, then it is more than likely that you take much longer than you expect, and the adhesive can dry out whilst you are working on the next step.
Correct adhesive consistency
You need mix the plaster well so there is no powder left and to a consistency that allows you to hold a good dollop of the mix on a trowel so it will not spill off. Many people use the analogy of a creamy texture, but this encourages people to mix it too thinly. A fun test is to flick a small blob on to undecorated wall or the inside of a dry bucket, if it sticks and the blob stays in shape its good, if it drips down its too thin, if it falls off its too dry. When mixed you can your mask and move on to the next step.
Applying adhesive to the coving
Now take a length of your coving and turn it on its front being careful not to damage its face. Damage usually occurs to the front of the coving at this stage because people get engrossed in applying the adhesive and forget to take care of the front. Take the filling knife and apply the adhesive in the correct amount to the back. The correct amount is normally around four to seven millimetres thick and applied so there is a gap between the edge of the coving and the start of the adhesive, this is so that when you present the coving to the ceiling and wall, and then press it in, the adhesive squashes into this gap leaving minimal adhesive to be cleaned off. You also do not need to add adhesive to the middle of the back of the coving because this part does not touch the wall or ceiling. By this stage you should now have two lengths of coving that’s ready to be installed.
Put the coving in place
Dampen the walls
If you’re fixing coving to freshly plaster walls that have not been painted, you must first dampen them with water, otherwise they will suck all of the moisture out of the adhesive too quickly, which will dry it out to quickly. If it dries too quickly you have less time to perfectly position the coving. To dampen the walls simply take a wet paint brush and paint water on the areas where the coving will be positioned.
Presenting the coving to the wall
Now take one of the lengths of coving and lift it into place. Using the lines you added earlier as guide you can press the coving into position ensuring they are positioned correctly. You need to leave about two millimetres from the wall for the adjoining corner to have space to butt up to it. Expect a two to five millimetre gap between the coving and the wall and ceiling, and remember that a plaster wall may not be perfectly flat so some gaps may be smaller than others along the length of the coving.
Securing with panel pins
Once in place, the coving should stay up by itself if you have mixed the adhesive correctly and applied enough, but there is a chance it can slowly slip out of place when you move on to the next piece. To prevent slipping, take some panel pins and tap them into the wall and ceiling to hold the coving steady, if you have positioned the coving correctly your pins will be on or very close to the guide lines you put up earlier.
Tidying up the gaps
Scrape away excess adhesive
You now need to tidy up the edges and fill in any gaps between the coving and the wall and ceiling. First take your filling knife and put the front edge on the ceiling and the side against the coving. Pull the knife fairly firmly keeping the edges touching the coving and scrape away and excess, you do not need to be perfectly clean at this stage, do this for the top and bottom edges.
Fill in the gaps
Next take a small amount of adhesive on the front of the blade and firmly press the mixture in to any gaps that are present. Once you have filled any gaps, scrape away the excess again, and remove any big blobs of adhesive. Now you can tidy the edge up properly.
Take a sponge and gently wipe the adhesive along the gaps making sure not to pull any mixture from the gaps, and then wipe away any marks on the coving and wall, also do not make the area to wet especially if you’re using paper covered coving as this could ruin the smooth finish. When your coving is clean you can now move on to the next length.
Adding the next length
The key with adding the next mitred piece is to put the corner end on first and then press the rest up. Leave a small gap of about a millimetre between the two corners, making sure they are aligned; the lines you drew on earlier will also guide you, and then add your panel pins to hold it in place. Next take a small amount of adhesive on your finger and then spread this into the gap between the two mitres, clean and fill any gaps and then give a final wipe over with your sponge like you did on the previous length.
Now you can repeat the process for the rest of the room. When measuring, always measure twice to ensure you get the correct measurement. If your do get into difficulty please get in touch with us, we enjoy helping people, and will happily talk you through it over the telephone.
If you are looking for a more authentic and ornate coving and cornice, match existing plaster mouldings, or looking for a cornice installation service, then contact us today or why not download our cornice guide and brochure.