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  • Writer's pictureMatt Weber

Learning to Cope in 2020

When installing baseboards or crown molding, joining two 45-degree miters may give you a 90-degree joint, but a square joint may not work well for corners that are out of square. Even a perfect miter joint can end up developing gaps when the wood dries and contracts in winter. Unlike miter joints, cope joints have one trim piece butted against the adjacent wall at the corner. The joining trim piece is carefully cut to nest against the profile of the first. These joints work better for out-of-square corners and are less likely to reveal a gap when the wood shrinks.

STEP 1: Butt the first piece of molding into the corner and fasten in place.

STEP 2: Cut the second piece of molding just a few inches longer than its final length. Then, on the intersecting end of the second piece, cut a 45-degree inside miter.

STEP 3: Use a carpenter’s pencil to darken the edge of the mitered profile for better visibility.

STEP 4: Clamp the second piece of molding to a work surface and use the coping saw to cut along the pencil line. Angle the blade to back-cut the molding. Keep the blade about 1/16 inch to the waste side of the cutline.

STEP 5: When most of the wood is removed, use a file or sanding block to finish the cut and clean up the profile, revealing a shaped edge that will be the only point of contact between the intersecting pieces of molding.

STEP 6: Test-fit the molding against the first piece and make adjustments as necessary. Nail the molding into place and finish off by caulking the seam.

STEP 7: Proceed around the room to complete the installation, using the installation sequence shown in the diagram.


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