How To Cut and Install Crown Molding

Order of Installation

At inside corners, a coped end fits over a square-cut end. In rectangular rooms, the last piece is often coped on both ends. In odd-shaped rooms like this one, you can usually avoid double-coped pieces. Outside corners are formed by two miter cuts.

Coping 101

Coping a molding starts with a 45-degree cut on the miter saw, just as if you were going to make a miter joint at the inside corner. This cut leaves an edge along the face of the trim that acts as a guideline for your coping saw. Cut along that edge and the resulting shape will fit against an adjoining piece of crown molding. Chances are your first attempt won’t turn out perfectly, but after a couple of practice runs you’ll be able to make good-looking inside corners. Here are some tips for smooth, successful coping:

• Every time you cut a miter (whether for coping or outside corners), you’ll set the crown molding upside down against the saw’s fence. It’s easy to get confused and cut the angle backward. To avoid mishaps, hold the crown molding up to the corner and draw a slash showing the direction of the cut.
• Clamp the crown molding to the work surface. Sawing is a lot easier with the molding locked into place.
• If the saw blade tends to slide to one side as you start a cut, make a small starter notch with a utility knife.
• Make sure the teeth in your coping saw point toward the handle. That way, the blade will cut smoothly on the pull stroke.
• Don’t force the saw forward. Make even strokes, apply only light pressure and let the blade advance at its own pace.

Tips for the Best Crown Molding Fit

Making a piece of crown molding fit between two inside corners is a combination of careful measuring and trial and error:

• Don’t bend the tape measure into crown molding corners and guesstimate the measurement. Instead, measure in from both corners and add the two measurements.
• Make a square cut on the end of the molding. Don’t assume the factory cut is square.
• To prepare for coping a molding, measure from the square end and mark the miter cut position on the bottom edge of the crown molding.
• Don’t make your miter cut exactly at the mark. Instead, cut the piece about a nickel’s thickness too long.
• “Spring” the molding into place. If it’s too long, shave a hair off the square end and try again until it fits just right.

More on Corners and Copes

Outside corners
The joint at an outside corner is formed by two simple miter cuts, but making them fit takes several steps. Don’t rush the process—outside crown molding corners are usually prominent, and so are mistakes. If the crown molding will have a varnish finish, select two pieces with similar grain patterns.

Double copes
If your room doesn’t have any outside crown molding corners or require scarf joints, you’ll finish the job with a piece that’s coped on both ends. This isn’t as tough as you might think. The key is to start with a piece that’s mitered to the right length. Miter both ends and hold the piece in place to check the fit. Then cope the ends as usual.

Scarf joints
On a wall that’s too long for a single piece of molding, you’ll have to ‘scarf’ pieces together. The angled cuts of a scarf joint are less visible than square cuts. If you plan on a varnish finish, select pieces that have similar color and grain patterns. Cut and install the longer piece first so the shorter piece can overlap it at the joint. Glue the joint.

Odd-angle corners
Coped joints only work in square crown molding corners. If you have nonsquare inside corners—such as 45-degree corners in a window bay—you have to miter them. Treat odd angle outside corners just like square outside corners.