How to Install Synthetic Chair Rails

Mark the wall at the desired chair rail installation height, typically 30 to 36 inches from the floor. Use a stud finder and a chalk pencil to find and mark the framing stud positions, a few inches above the installed rail’s position. Mark the wall again where the molding’s upper edge crosses each framing stud.

Rotate the miter saw blade to the left to make a 45-degree cut. The blade is rotated to the left for cutting the molding’s left end and to the right for cutting the molding’s right end. The cut ends are divergent, not parallel. Trim the left end of the molding to 45 degrees by placing the side of the molding that will be positioned against the wall against the saw's guide fence.

Measure and note the wall’s length from corner to corner where you intend to install the chair rail’s first section. Transfer that dimension and mark the top edge of the trimmed rail where it meets the molding’s back surface. Rotate the miter saw to 45 degrees to the right, a total of 90-degrees rotation. Trim the molding’s right end.

Position the molding on the wall by aligning it to the reference marks. Have an assistant support one end of the molding as you support the other. Mark the positions of the wall studs on the molding with a chalk pencil. Remove the rail. Using a bit with a slightly smaller diameter than the finishing nails, drill a pilot hole through each mark. Hammer a finishing nail partially through each pilot hole.

Reposition the rail on the wall, aligning its top edge with the positioning marks. Hammer the nails through the molding into the studs. Leave the nail heads protruding from the molding about one-eighth inch. Place the nail set’s tip set on the first nail’s head. Hammer the nail set so the finishing nail’s head is slightly below the molding’s surface. Once all of the nails are set, fill the nail holes with a bit of latex caulking. Wipe away excess caulking with a wet finger.

Measure and note the adjoining wall’s length. Locate and mark the positions of the framing studs on the wall and install remaining portions of the chair rail in the same manner.