How to Hang Crown Molding on an Uneven Ceiling

Measure the wall with a measuring tape. Hold the measuring tape at one end of the wall and have a partner take the measurement at the other end of the wall. Write down the measurements on a piece of paper.

Transfer the ceiling measurements directly onto the crown molding using the measuring tape and a pencil.

Set up the miter saw at a 45-degree angle so you are ready to cut the molding. The direction of the angle will depend on the type of cut that you are making. Scarf cuts are made when connecting two pieces of molding in the middle of the wall. The direction of the 45-degree angle does not matter for scarf cuts, but both pieces of molding must be cut in the same direction. Outside corner cuts are made with left- and right-hand 45-degree angle cuts. The two sides of the corner are cut at opposite angles. Cut one side of inside corners to a 90-degree angle and the second side of the corner to a 45-degree angle. Remove the back portion of the angled piece of molding with a coping saw. The coped side of the molding should fit into the profile of the other side of the corner.

Position the molding on the saw so that the top of the molding rests against the miter saw table and the bottom touches the saw fence. The molding should be in this position whenever it is cut. Cut the crown molding to size with the miter saw.

Set the crown molding in place on the wall. Try to position the molding as close to the uneven ceiling as possible. Have a friend help you hold the molding in place. Nail the moldings to the wall with a pneumatic nail gun and finish nails. The nails should be spaced every six to eight inches. You do not need to use glue to glue the molding joints. There will be some gaps between the molding and the ceiling because the ceiling is uneven.

Caulk the gaps between the crown molding, and the ceiling and wall. Spread a bead of paintable acrylic latex caulk along the gaps. Use a wet finger to smooth out the caulk. Let the caulk dry overnight and paint the molding as desired.