Remodeling 11: How to Cope and Install Crown Molding

COPE: To cut or shape the end of base molding or crown molding so it will cover and fit the contour of an adjoining piece of molding.

We generally cope the inside corners of baseboards and crown moldings. This started in "the old days" when air nailers were not invented yet. A carpenter would nail everything by hand. He noticed that in an inside corner of molding, if the base molding was mitered, the opposing corner of molding would have a tendency to open up with the hammering process, making it tough to get a nice tight joint. Mr. Cope came along and thought that if he could easily cut the profile square on the opposing crown molding, as he nailed it in place, it would remain a tight joint because it would slide along the crown molding instead of opening up. This was explained to me, at a very young age, by my father and I never forgot it. The part about "Mr. Cope" is writer's privilege, sorry about that.

Diagram of a coped corner showing how the coped molding fits onto another piece of the same molding.Now, to actually cut the cope joint. On one side of the inside corner of molding measure the length of the required base molding or crown molding, cut both molding ends square and fasten it in place. On the opposite inside corner of molding cut the crown molding at a 45° as if you were going to miter the molding joint. The cut edge will show the profile of the crown molding to follow. Use a coping saw, hence the name. Instead of cutting the molding profile square on the end, bevel it back just slightly, so in case of adjustment there is less material to remove this way. See the picture, below.

Photo of how to use a coping saw to cut and shape the end of molding.

When installing crown molding, I prefer not to cope the inside corner of the molding. For one thing, I always use a nail gun and the second thing is the crown molding is viewed from below, not giving as nice a cut as a miter. If tying in a crown with one that is already in place, then a cope joint is necessary. Follow the same procedure as coping a baseboard.

Coping crown molding—try it, you'll like it.


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