Crown Molding Installation

Planning Your Space for Crown Molding Installation

When installing a cornice or crown molding it is important to establish a plan for the layout.
Start by measuring your room to determine linear footage of crown molding needed. Add 10% of total length for miter waste. Divide total linear feet by crown molding lengths.
For example: if crown molding comes in 8 – foot lengths, divide total linear feet by 8. Round up the number of lengths needed to determine total number of crown molding lengths you will need to purchase.

You may also want to consider adding additional length to your purchase to "match the pattern" of molding, ensuring a consistent appearance. For molding with repeats greater than 6" consider adding an additional 5% of total length.

Always store molding in a dry well-ventilated, low humidity area. Never store molding outdoors.

Before Crown Molding Installation

You can finish (paint or faux finish) crown molding before or after installation. After installation touch-up areas as needed.

Place crown molding in room for 48 to 72 hours before installation to allow molding to adjust to room temperature and humidity levels of the room

Surface Preparation for Crown Molding Installation

Clean all surfaces free of dirt and loose particles with a clean cloth or sponge. Make sure area is completely dry before installing crown molding

Tools and Material for Crown Molding Installation

Tools and Material
- Sponge or clean cloth
- Caulking gun
- Miter box and saw or power miter saw
- Chalk line box and pencil
- Polyurethane construction adhesive

Optional Tools and Material
- Putty Knife
- Hammer and nail set
- Elastomeric adhesive caulk
- Extra fine sandpaper
- 6d or 8d finishing nails (bright finish or electro-galvanized) fasteners must penetrate substrate a min. of 1/2" to 3/4"

Mitering Crown Molding Corners

The key to successful mitered corners is placing the crown molding correctly in the miter box or power saw fence/rail.

Crown molding should be placed in the box so that the ceiling bedding edge of the molding lies against the bottom of the box or saw and the wall bedding edge of crown molding lies against the side of the miter box opposite you. Tip: Before cutting, label the miter box or saw bottom "ceiling" and the side with "wall" (A).

Cut all miters and butt joints before you install crown molding. After cutting, lay crown molding in place around the room to make sure all cuts and joints are correctly measured.

mitering inside crown molding corners

Take two pieces of crown molding that will be used for your inside corner.
Place the "left" length of crown molding in the box as described above and cut 45° mitered corner – your saw should point left (B).

Next place the "right" length of crown molding in box – before cutting note molding pattern and adjust your cut to allow for continuity of pattern.

Cut the right miter with your saw pointing right (C).

Check your cuts by placing the two mitered ends together, to ensure a good fit.

Mitering Outside Crown Molding Corners

Take two pieces of crown molding that will be used for your first outside corner.

Place the "left" length of crown molding the box as described above and cut 45° mitered corner – your saw should point right (D).

Next place the "right" length of crown molding in box – before cutting note crown molding pattern and adjust your cut to allow for continuity of pattern. Cut the right miter with your saw pointing left (E).

Check your cuts by placing the two mitered ends together, to ensure a good fit.

crown molding butt joints

When crown molding lengths do not span the entire length of a room, you will need to "butt joint" two crown molding lengths together.

Note the pattern on the cut crown molding and adjust the pattern on next length of crown molding when cutting to insure pattern continuity.

Lay the crown molding in the miter box the same as described above and cut a straight edge (F).

General Crown Molding Installation

First mark the entire length of wall around the room with your chalk line box and pencil. You will mark the bottom edge of the crown molding.

Always start installing crown molding behind a door or at an inconspicuous corner, because the repeat pattern of your last joint will most likely not match at the joint.

Apply a 1/4" continuous bead of construction adhesive along the backside top and bottom edge of crown molding (G) and at butt joint ends. Use adhesive to fill any gaps.

Gently press the crown molding edge and smooth excess chalk with your finger or putty knife, giving the appearance of the crown molding being part of the wall (H).

Wipe any excess adhesive from edges and clean with mineral spirits.

Option: You may want to tack or secure crown molding into place with finishing nails. If you want to remove nails after construction adhesive dries, leave approximately 1/2" nail exposed for easy removal.

Tip: Nail crown molding in ornamentation areas of molding into wall. When adhesive dries (approx. 2 -3 hours) either remove the finishing nails or use nail set to countersink nails, making sure that nails penetrate wall at least 1/2" to 3/4".

Fill nail holes with Elastomeric adhesive/caulk – smooth the surface with your finger or putty knife. Once caulk is dry and if needed, lightly sand crown molding rough spots with extra fine sandpaper.

Paint or touch up crown molding with paint as needed.