How to Build a Mantel for a Fireplace Insert

Measure the height and width of the area you'll install the mantel and surrounds with a tape measure.

Cut three of the pine boards on a table saw with a circular saw to the dimensions you need. The mantel should span the width of the fireplace facing and the two pieces for the surround.

Cut three pieces of molding to match the measurements of the length and two sides of the mantel board, using the circular saw.

Slide the stud finder over the wall around the fireplace. Mark the studs' location on the wall with a pencil.

Apply construction adhesive with the caulking gun to the backside of each board for the surround. Set the first one vertically on the outside of the fireplace facing, with the glued side against the wall. Hold the level against it to make sure it is even. Nail the board to the wall with the nail gun where the wall studs are marked. Do the same with the second board for the surround.

Apply construction adhesive with the caulking gun to the back edge of the mantelpiece you cut. Set it on top of the surround boards with the glued edge against the wall above the fireplace facing. Hold the level against it to make sure it is level. Drive interior-grade nails through the top of the board into each of the boards on each side, and to the wall with the wall studs.

Cut the ends of the molding you'll use to edge the mantel board with the miter box and saw. Cut the ends that will meet at the front corners of the mantel at a 45-degree angle so they will fit together. Apply construction adhesive to the back of each piece of the molding and fit the pieces around the front edge of the mantel board. Drive finishing nails into the trim with the hammer to further secure them to the mantel.

Sink all exposed nail heads with the nail set. Place the tip of the nail set against the nail heads and tap the back of it with the hammer to sink the nail head below the surface of the board. Cover all the nail holes with wood putty, using a putty knife. Sand the putty when it dries with the sandpaper.

Paint or stain your mantel and surround with a paintbrush and interior paint or stain of your choice.