How to Add Crown Molding

Measure the length of one wall that will receive the crown molding, with a tape measure.

Place a sliding bevel in the corner, with the bevel and handle each firmly against the corresponding walls forming the corner. Tighten the lock nut on the bevel to hold the angle. Place the sliding bevel against a combination square to determine the corner's angle. Divide this number by two to get the angle at which each piece of crown molding in this corner must be mitered.

Place a piece of crown molding on the miter saw, and tilt the back of the molding against the fence so it's at the same angle at which it will be installed on the wall.

Measure the desired length, and make a pencil mark at the cut line along the back edge of the molding (against the fence).

Rotate the base of the saw to the angle you determined in Step 2 (which is one-half of the wall angle measurement).

Hold the molding against the fence and the table at the proper angle, and with your hand well clear of the blade. Depress the saw's trigger, then push down on the miter saw to cut the angle into the molding.

Position the piece on the wall against the ceiling, with the molding tilted to the proper angle. The bottom of the miter cut should align with the wall corner perfectly. Tack the molding in place with a pneumatic finish nailer, nailing through the crown molding's edges, through the drywall and into the stud or ceiling joist behind.

Work your way around the room using these steps for each piece of molding.