DIY Fireplace Mantle Kits

Measure the height and width of your fire box (the area where the fire burns). Measure the height and width of the fireplace surround and hearth. The surround may be a floor to ceiling wall of brick or it may be 18-inch marble tiles surrounding the fire box. Measure any width limitations like the proximity of windows or cabinets. Your mantle needs to fit around your fireplace so that it covers the edges of the surround (the marble in this example), is the correct scale for your fire box and the mantle will fit within the provided wall space.

Purchase and assemble your mantle kit. Typically the kit will consist of the top mantle and two leg sections. All of the pieces will be hollow. The top will attach to the legs using simple brackets and screws that will be provided in the kit.

Position your assembled mantle centered over the fire box. Place a level on top of the mantle to ensure that it is straight and level. Draw the outline of the mantle onto the wall. This will provide a guide as you install the mantle.

Lay the mantle face down on the floor. The mantle will attach to the wall using cleats. A cleat is a piece of 2-by-4-inch board that is cut to fit inside the hollow portion of the mantle top and each leg. Measure the hollow area. Cut your 2-by-4-inch board and fit it into the top of the mantle. The top board of the mantle will rest on and be screwed to the cleat from the mantle top.

Cut and fit your cleats for each leg. Mount your cleats to the fireplace wall. Measure the location of the cleat (the outline will help you with positioning). Drill a 1/2-inch deep pilot hole and screw 2 1/2-inch concrete screws into a brick wall. Don't drill into the mortar, as the brick is stronger. If your wall is drywall and studs, use 3-inch deck screws instead. Attach all three cleats to the wall.

Slide the mantle up over the cleats. It should match the outline and fit easily. Screw through the top back side of the mantle into the cleat using recessed head screws. Space your screws every 12 inches. Screw through the outside of each leg close to the wall and into the cleats using recessed head screws spaced 12 inches apart.

Fit the trim pieces the attach around the inside edge of the mantle. These are usually pre-cut and provided with the kit. Nail 4d finishing nails every 12 inches. Recess your nail heads. Fill your nail head and screw holes with wood fill. Allow the wood fill to dry for 4 hours and then sand smooth. Caulk around all sides of the mantle with a paintable caulk.