Installing crown moulding

Plan your installation.

Some joints are more visible than others, and these are the ones you want to look best. Experienced carpenters install crown moulding in the order above for the easiest and best-looking job. Start on the wall opposite the door (1 ) and install a piece that's square at both ends. This presents the best (and easiest to cut) side of the joint to anyone entering the room. The moulding on the second wall (2) is coped where it meets the installed moulding, and square where it meets the other wall. The third wall (3) is treated the same way, and the fourth wall (4) is coped at both ends.

Measure the room and mark the stud locations.

You'll nail the moulding into the wall studs. Locate the studs with a stud finder and make faint pencil marks high on the wall (where they won't be covered by moulding) to guide you as you nail.

Put the moulding against a framing square,

noting the distance between the face of the moulding edge and the corner. Cut a scrap of lumber to the correct dimension and draw layout lines on the wall and ceiling. When you install the moulding, align it with the layout lines.

Begin at the wall opposite the door

and cut moulding to that length. Mark the locations of the studs by holding the moulding in place and transferring the marks onto the moulding. To prevent splitting drill pilot holes the diameter of the finishing nails drill holes at each mark at the top and bottom of the moulding. Nail in place.

Lay out the cope joint on a second piece of moulding;

start with a piece a few inches longer than finished length and flex it in place. At the end you'll cope, draw a line in the general direction you'll cut at roughly a 45-degree angle (it's OK if the line isn't straight).

Set up the miter saw.

Position the moulding so that the ceiling edge is flat on the bottom of the miter box and the wall edge is tight against the fence. Set the saw to cut at 45 degrees in the general direction of the line you drew in Step 1. (If the blade and line won't even come close to aligning, turn the moulding upside down and try again.) Cut a miter close to the end.

Undercut along the profile with a coping saw.

Look at the face of the moulding; the miter cut exposed the profi le of the moulding, outlined here in pencil. Cutting away the excess wood beneath the profile creates an outline that can nest against the adjacent moulding. Tilt the coping saw back at a 45-degree angle to create a razor-thin edge where the two mouldings will meet.

Test-fit the cut.

Check the joint by fitting it against a cutoff. Be prepared for an imperfect fit; even experienced carpenters may have to fine-tune the joint until it fits.

Sand and file any high spots to create a tight fit.

When the joint fits, measure the wall. Cut the moulding 1⁄8 inch longer than measured (usually by making a square cut on the uncoped end). Flex the moulding in place the extra length will help push the cope joint closed.