How do I Build a Mantel for a Chimney?

Place the 1-by-6-by-48-inch lumber (front of the frame) on the worktable along with the two pieces of 1-by-6 by-8 3/4-inch lumber (sides of the frame). Apply glue to the 5 1/2-inch ends of the 1-by-6 by-8 3/4-inch and secure them on either end of the 1-by-6-by-48-inch lumber. Secure them with the finish nails.

Apply glue to three edges of the 1-by-6-by-46 1/2-inch lumber (stabilizer). Set it between the 1-by-6 by-8 3/4-inch sides, let it rest on the 1-by-6-by-48-inch lumber (front) and make it even with the 3/4-inch edges of the frame. Secure it to the frame through the sides with the finish nails. Turn the frame over so the front (48-inch lumber) is facing up and drive the finish nails through the front of the frame into the stabilizer (46 1/2-inch piece).

Put the 1-by-12-by-52-inch piece (top of mantel) on the worktable. Measure from one corner and make marks on one of the 52-inch edges (becomes the back edge of the top) at 2 and 50 inches. Set the frame between the marks on the 52-inch edge and set the back of the sides even with the back edge of the top.

Run a bead of glue just inside the marks and secure the frame to it through the stabilizer with the 1 1/4-inch drywall screws. Clean up the excess glue with a damp cloth.

Glue the exposed edges of the frame. Set the 1-by-10-by-48-inch piece (bottom of the mantel) on the frame. Secure it to the frame with the finish nails. Clean up the glue as before. Turn the mantel over so the front of it is facing up.

Set the 1 1/4-inch side of the flat decorative molding against the fence of the electric miter saw. Cut a 45-degree angle on one end of both pieces. Set them on the front of the mantel frame so the back of the miter is even with the left side of the frame where it turns toward the back of the mantel.

Mark the molding on the right side of the frame (where it turns toward the back of the mantel). Cut the pieces on the mark at a 45-degree angle with the electric miter saw. Repeat this process on the left and right sides of the frame.

Secure the flat mold to the frame with 1-inch brads. One installs on the bottom of the frame and the other installs where the frame meets the top of the mantel.