How to Install Three-Piece Crown Molding

On long runs that require two lengths of molding, an angled scarf joint minimizes the seam between the pieces. For a tight fit, adjust your layout so that the joint will land just past a stud or joist, or on a backing block. Cut the ends of the molding at parallel 30-degree angles. The first piece to be installed should have an open miter with a longer back side and a shorter face, as shown. Position the piece with the open miter on the wall and nail it in place to the framing, but don’t add nails within a few inches of the scarf cut for now. Apply glue to the cut end.