If you have any external corners (such as a chimney breast), start installing the coving with them. Otherwise start at the first corner you see when entering the room (it is always easier to get the 1st corner of the installation correct, so make sure it is the most noticeable corner in the room).
Establish a suitable area that clearly shows the separation of the wall from the ceiling where the coving will be fixed at and ensure this is clean and sound. Draw a line around the room at this position (or mark at various points), ensuring the line is horizontal (note: don’t be tempted to follow the ceiling which may not be level however if there is any subsequent gap, this can be filled later). At every 500mm or so, tap a small pin nail into the wall as a temporary supporting guide (note: the small nail holes will eventually be covered by the adhesive/filling compound). For extra adhesion you can score the area between the line and the ceiling. As another option, repeat this process on the ceiling.
Now, carefully measure along the wall the length you need and then measure it again! Transfer these measurements to the coving, and if it helps also mark a line in the direction that the cut will roughly be so that when put in the mitre box you can be assured you are cutting in the correct direction.
Make the cut, then offer up to check you are happy that the two sections meet. Don’t worry if they do not meet perfectly as not many rooms have corners that are exactly 90° so a perfect join is rare. That’s where careful use of the filler comes in later to give the illusion of a perfect join.
Using the adhesive, apply along the entire length of the back edges of the coving where it will meet the wall and ceiling. As a rough guide to coverage, a 310 ml cartridge should be sufficient for 6-8 m.
Using the line on the wall as a guide and the nails as a lever, push the coving firmly into place, adjusting as necessary. Now apply a thin layer of jointing cement to the end of the coving where it will meet the next piece. This will give an ultra high strength join and prevent any cracks appearing in the future (Note: if applied correctly, the join will be stronger than the actual coving piece itself).
Repeat the above process around the rest of the room.
Remove any excess adhesive and use it to fill in any gaps – between joins and between coving and wall/ceiling. Use your finger, a filling knife and a damp paintbrush to smooth over, followed by a wet sponge to wipe off any remaining adhesive. Finally after allowing 3-4 hours for the adhesive to dry, remove the nails and fill the holes as above.
The coving is pre-finished with an undercoat/primer already applied, so it will be ready to paint after 24 hours. Although any paint is suitable, remember that emulsion is water based. This means that it may suffer hairline cracks if there is excessive movement or vibration in the ceiling. Acrylic/oil based based paints have more “elasticity” in them so are less prone to these fine cracks.