How to Make Mission Style Fireplace Mantels

Measure the fireplace. Generally, building codes require a 12-inch clearance between the firebox and a wood mantel. Mark points on both sides and above the fireplace that are at least 12 inches from the fireplace opening using a piece of chalk.

Locate the wall studs using a stud finder. There are normally studs surrounding the fireplace.

Cut the 1-by-6 boards to fit around the fireplace, using the earlier measurements, and butting the two vertical supports to the bottom of the horizontal board. Use a spirit level to ensure that the boards are perfectly horizontal and vertical. Attach the boards to the wall studs with 8 deck screws per board, spaced equidistant across the boards and 1 1/2 inches in from each side.

Apply construction glue to the back of each of the 4-by-4-inch squares. Attach a square at the bottom of each vertical support, centering it on the board. Tap a finishing nail into each corner, using a nail set to push the nail head slightly below the surface of the wood.

Glue and nail the other two squares in place, flush with the top of the horizontal board and aligned vertically with the bottom squares.

Measure and cut the decorative casing to fit between the squares on the vertical boards. Glue and nail into place.

Measure and cut a piece of 2-by-2-inch board to fit on top of the horizontal board. Attach it to the wall studs, butting it against the top of the board.

Cut the last 1-by-6 board 4 inches longer than the width of the fireplace surround. Measure and cut the crown molding to fit onto three sides of the board, using a miter box and saw to cut the molding. Glue and nail the molding to the board.

Fit the mantel top and molding on top of the 2-by-2 support. Predrill down through the top and into the support. Attach the top to the support with wood screws.

Fill over the top of the finishing nails and screws with wood putty. Allow to dry, then sand smooth with 180-grit sandpaper.

Mask the wall and bricks around the mantel with painter's tape.

Apply a dark oak or walnut stain to the wood with a rag. Wipe off the excess with a clean rag and allow to dry completely.

Brush two coats of satin-finish polyurethane over the entire mantel. Allow to dry between coats according to the manufacturer's instructions.