Cement board has an inner core made of cement and a paper layer on either side that makes it resemble drywall. The sturdy, moisture-resistant board is applied to surfaces as the base for ceramic and natural stone tile. You can install cement board to virtually any surface, including a brick fireplace. However, to secure it to the brick surface, a wooden framework is required to provide support for the heavy cement board.
Things You'll Need
1-inch by 3-inch wood furring strips
Hand saw or power saw
1 1/2-inch-long, 1/4-inch masonry drill bit
Stainless steel screws
Measure the vertical height of the brick fireplace using a tape measure. Cut 1-inch by 3-inch wood furring strips to the same length using a hand saw or a power saw.
Place one of the furring strips vertically on the left edge of the brick fireplace. Mark the brick every 12 inches down the furring strip, and then make corresponding marks on top of the furring strip. Set the strip aside.
Don hearing protection and safety glasses. Insert a 1 1/2-inch-long and 1/4-inch-diameter drill bit into a hammer drill. Plug in the cord of the drill, and drill a 1 1/2-inch-deep hole at the location of each mark on the brick.
Turn the wood furring strip over, and apply construction adhesive over the entire length, using a zigzag pattern. Press it against the wall in the same location as before, and hold it for 10 to 15 seconds.
Insert a concrete anchor screw into each marked location on the wood strip, using a power drill.
Install additional furring strips along the entire width of the brick fireplace, spacing them every 12 inches. If 12-inch-interval spacing is not feasible, space the furring strips at equal distances across the width. When you reach the opening of the firebox, reduce the height of the strips so they cover only the brick portion and not the firebox opening. Wait 24 hours to allow the construction adhesive to set up firmly.
Place a sheet of cement board on a table, and measure it vertically to determine whether it is taller than the height of the fireplace. If needed, trim it down using a utility knife. You will position the cement board vertically when you secure it to the fireplace furring strips.
Place the cement board up to the brick fireplace, and insert stainless steel screws along the location of the furring strips, using a power drill. Space each screw at 8- to 10-inch intervals.
Install all of the remaining cement board sheets in the same manner. When you reach the opening for the firebox, cut the vertical height of the cement board shorter to fit only the upper brick area. Do not cover the opening of the firebox.
Apply strips of alkaline-resistant tape over all cement board seams, and spread drywall mud over the tape until you cannot see it. Wait until the mud dries, and sand it smooth using a piece of fine-grit sandpaper. The wall is now ready for the installation of tile or stone facing.