Crown molding corner blocks – First, begin by using double-sided tape to attach the corner block into the wall. If the walls are not square, use a file to shape your corner block to passé. Install the corner blocks. Second, measure your first piece of crown blocks. If it is too long, cut it like as you need. Make sure that it will fit well. If wall is longer than a single section of crown molding you have, you can use a relay bloc. Disuse similar crown molding corner blocks but they go in the center of a straight. Till walls, use a relay bloc….