4-x-8-foot sheet of 3/4-inch medium-density fiberboard (MDF)
30+ linear feet of 1/2-x-1-1/2-inch flat wood molding
30+ linear feet of 1/2-x-3/4-inch ogee wood molding
8+ linear feet of 2-1/2-inch wood crown molding
1 pound 4d (1-1/2-inch) finishing nails
1 pound 6d (2-inch) finishing nails
1 package No. 10-x-3-1/2-inch drywall screws
1 package No. 8-x-2-1/2-inch drywall screws
Construction adhesive (cartridge-type)
Latex caulk (paintable)
1 quart each latex primer and latex semigloss paint
Tools You Need
Portable circular saw with straightedge guide
Clamps (6-inch or larger)
Drill bits (1/16, 3/16 with countersink)
No. 2 Phillips screwdriver (or driver bit for drill)
Sanding block with 120-grit sandpaper
How to Make It
Because fireplace sizes and types vary so much, use the components and dimensions of this project as a starting point rather than a specific guide. Also, check with your local building official to determine the minimum clearances you'll need from the firebox opening to the columns and mantel; the allowable proximity of combustible materials to an open flame is governed by building codes in most areas, and you'll need to comply with local regulations. If you are installing or retrofitting a new metal fireplace, also check the manufacturer's instructions for information about minimum clearance to combustibles.
This fireplace surround features a classic frame-and-panel design, but the materials and construction methods simplify the process more than traditional techniques would. Except for the store-bought moldings, all of the components are built with 3/4-inch medium-density fiberboard (MDF). MDF has a smooth surface and holds paint well, but the edges are highly porous and often need multiple coats of primer.
Build the Sections
This assembly consists of several subassemblies (see illustration). You'll get better results if you build and install these sections individually, so start by measuring your fireplace area to determine the best dimensions for your surround. There are no absolute rules here, but you'll want to find pleasing proportions and meet the clearances required for using the fireplace safely. Our project measures 65 inches wide and 51 inches tall, with 7-1/2-inch-wide columns and a bridge beam to span between them. The exposed face/area of the bridge beam is 10 inches tall (an additional 2 1/2 inches along the top is concealed by crown molding).
The columns are a simple hollow box form, with butted edges secured with glue and 6d finishing nails. The front panel of each is fitted with a frame of 1/2-inch poplar trim to suggest a recessed panel, and the inside perimeter of the frame features a small ogee molding, cut to fit with 45-degree mitered ends at the corners.
The bridge beam has a shallower depth (front to back) than the columns, and it's simpler just to sandwich pieces of MDF together to make this. You can use three full-size pieces (laminated together with glue and finishing nails) or one full-size piece for the front panel and narrower strips around the edges to add the remaining two layers. This section also gets the faux frame-and-panel treatment using the 1/2-inch poplar trim and the ogee molding. Keep this detailing toward the lower part of the front panel to allow room for the crown molding to be installed later. For the mantel shelf, simply glue and nail two layers of MDF together.
Finish and Install
While the subassemblies are still separate, apply a coat of primer on all accessible surfaces; add one or two extra applications where the MDF edge is exposed. Lightly sand any raised grain and sharp edges or corners.
Apply one coat of the finish paint, preferably a latex semigloss enamel, and let it dry at least 24 hours so the paint has plenty of time to cure. In the meantime, fit the stone, tile, or other hearth materials in place. Install these with thinset mortar for the right support and adhesion.
When you're ready to install the surround, position the columns and fit the bridge beam between them, making sure the upper edges are flush with each other. Use 3-1/2-inch or longer screws to attach the beam to the wall. Fit the columns against the beam ends, and use 2-1/2-inch drywall screws to attach each column to the beam end and, if possible, to a wall stud. (For better holding power, you can apply a bead of construction adhesive to the back of the columns before installing.)
Use construction adhesive to attach the mantel shelf to the top of the columns and beam. Now check for any gaps between the sections or where the surround meets the wall and fill with a paintable latex caulk. Finally, apply at least one more coat of the enamel paint to the entire assembly.