How to Install Crown Molding

Crown molding-or cornice molding-is trim used where the wall meets the ceiling. This decorative touch can add a note of class and completion to a room. Because crown molding highlights irregularities in the wall or ceiling, use a long level or straight board to check that the walls and ceiling are straight enough so any gaps will be tolerable. Repair the surfaces before you start so the molding does not highlight the irregularities.

Crown molding comes in several sizes, made to complement different rooms. In our 12' x 10' dining room, ³⁄₄", 38° molding looked just right. Crown molding requires sequence, patience, and jigs. Sequence, because it's easiest to work your way around the room. Patience, because it will be seen by a V-I-P, namely Y-O-U. And jigs, because you'll cut the molding in a homemade jig. I buy extra molding. Although I generally paint or stain molding first, if you don't stain the extra molding, you can always return it.

Step 1: Been Workin' on the Nailer

Instead of nailing crown molding to the framing (the studs, plate, and joist), attach it to a nailer-a piece you attach to hold your nails. If you cut the nailer to fit the angle and size of the molding, it will practically fall into position on the wall.

Crown molding may rest at either 38° or 45° to vertical; cut this angle on the nailer, as described in a moment.

Position the nailers 4" away from the corners, to leave room for molding at the corners. Attach the nailer to the plate at the top of the studs with screws or staples 16" apart and slanting upward. Fasteners must grab 1" of the plate.

Step 2: The Nailing Sequence

With the nailer attached, turn your attention to the attaching the molding in the most efficient order, starting with corner.

Position the nailers 4" away from the corners, to leave room for molding at the corners. Attach the nailer to the plate at the top of the studs with screws or staples 16" apart and slanting upward. Fasteners must grab 1" of the plate.

Most pieces of crown molding get a butt (square) cut at one end and a coped or mited joint at the other. Use this sequence for fastening:

1. Cut two 4" scraps of molding and tack (lightly nail) them into position at corners A and F, along the walls shown.

2. Miter (angle cut) one end of a piece of molding longer than dimension A-B. Cope one end and test it against the block at F. When it fits, make a butt cut at the other end so the piece fits wall A-B.

3. Tack this piece to wall A-B, snug against the block at A. Remove that block.

4. Continue around the room, using scrap blocks for each coped joint.

5. Make a miter joint at the outside comer, D.

6. You can't test the coped joint on the long side F-A, because the molding would be longer than the room until you make the butt cut. If you are worried about cutting an accurate joint, cut side F-A in two pieces, joined with a scarf joint.