Crown Molding Techniques

Measuring

• Calculating precise lengths and angles is the key element to creating an attractive crown molding job. Imperfections in drywall, taping and the studs behind walls result in corners that often don't meet at exact 90-degree angles. Measuring the angles accurately with a protractor or similar device lends precision to cuts and results in tight-fitting joints. Rather than transferring measurements from a tape, some installers, like Tom Silva of "This Old House" prefer to hold crown molding in place on the wall and mark cuts at the corners.

Cutting

• Contrary to what might seem proper, crown molding is best cut upside-down and backwards on a miter saw. In this position, the molding more closely resembles the way it will be installed on the wall. Think of the saw's bed as the ceiling and its vertical fence representing a wall. The wider of the two bevels fits against the vertical fence and on the wall when the molding is nailed in place.

Coping

• Some molding joints need to be coped with a special saw designed for the task. Coping is removing some of the material from behind the edge of the molding so it will fit neatly against a mating piece of crown molding. This joint technique is often used on inside corners of the room and, when done correctly, the result looks like a perfectly mitered joint.

Scarf Joints

• Sometimes walls are longer than the length of crown molding that can be purchased. Scarf joints are 45-degree angled cuts made into each of two matching ends of crown molding so they can be glued and nailed together, creating the appearance of one long, continuous piece of molding.

Installation

• Crown molding is typically nailed 16 inches on center to wall studs and ceiling joists. Since the molding creates a void behind it because it is installed on an angle between the wall and ceiling, Tim Carter of AsktheBuilder.com suggests adding an angled nailer along the wall-to-ceiling joint and nailing crown molding to that piece to give the work more stability and more nailing options.