Install cornice or crown moulding

Forget about a hammer and nails, you can easily install the new style polystyrene crown moulding and cornice with cornice adhesive and a caulking gun.


Before installing crown moulding, test fit a piece of molding in place and mark the height of the moulding where it meets the wall below the ceiling. Use a level, or laser level, to extend this mark along the walls from corner to corner. Install the molding holding it up and shifting the placement until the edges lay flat against both the wall and the ceiling surfaces.

Leave the ends until last to allow for adjustments when joining the matching corner pieces. At the corners, shift the moulding to expose the ends enough to brush the both edges with a thin coat of cornice adhesive Join the corners adjusting the two piece together until they form a smooth union that lays flat against the walls and ceiling. Wipe away any adhesive that squeezes out - before it has time to set.

For longer pieces you’ll need some help holding it in place while you push to attach it to the wall. Use the caulk gun and cornice adhesive to cover up any gaps in the joint.

Where horizontal or lengths of moulding meet, join them together with overlapping 45-degree-angle cuts. This will prevent visible gaps from opening at the joint.

Apply cornice adhesive to the inside of the 45-degree cuts to get a tight seal then secure the pieces together and hold with masking tape until dry.

For corner seams and joined sections, apply cornice adhesive to the cut ends and then secure onto the wall. Wipe away any excess adhesive that may ooze out of the seam.

If you make a boo-boo and the molding is too short, cornice adhesive can be used to fill small gaps. If it's a large gap in the joint, cut a new piece to correct the error.

If you have speaker cables, security wiring, or other cables that run around the edge of the ceiling, you can easily hide these behind crown moulding.

In most homes you will find that corners are rarely perfectly square. To avoid problems and wasted material, first cut and join short random-length moulding pieces to fit all outside and inside corners.

It's easier to work with short pieces and make trial-and-error cuts if necessary to get a tight fit in each corner than to attempt to make longer lengths meet precisely.

After cutting the corner pieces, use cornice adhesive to attach to the wall, and No More Nails to fill in any gaps where sections join together.

Tips on using a mitre saw for cutting corners for crown moulding and cornice

Set the saw by tilting the blade and setting the bevel angle at 45° using the guide on the back. Leave the bevel setting at this position throughout cutting procedure.

Note: Some compound mitre saws have a double bevel feature. This means the saw blade can be tilted left and right instead of just to one side. When using a double bevel saw for the following procedure, use only the left bevel position.

Set the mitre angle by moving the saw table left and right of centre. The position will alternate depending on which corner piece will be cut. Set the saw table at 45° – right to cut the piece that will form the right inside and left outside corners, pieces C and D pictured above. Cut these pieces with the moulding ceiling edge against the saw fence.

To set the saw for the matching pieces, slide the saw table to the left and set it at 45°. With this setting the left inside and right outside corner pieces, A and B, can be cut. Turn the piece so the wall edge is against the fence to make these cuts.

The inside corners, A and C, will always be on the left of the blade and the outside corners, B and D, will always be on the right.