How to Build Mantel Tops

Assemble the wood mantel kit according to the manufacturer’s directions. Each mantel kit features a shelf or mantel and two legs attached to a corner along its lower surface. Ensure the legs are straight and tight when installed.

Push the mantel flush against the wall above the fireplace. To prevent a fire hazard, allow at least 6 inches clearance space between the mantel and the fireplace opening. Lay a carpenter’s level along the top of the mantel to ensure it is level. If required, tap the legs against the wall to center the mantel directly above the fireplace.

Draw a horizontal line on the wall using the upper edge of the mantel as a guide. Remove the wood mantel and carefully lay it on the floor. This line forms the guideline for the cleat that will secure the mantel to the wall.

Extend a measuring tape along the inner width of the fireplace shelf or mantel and record it. Cut 2-by-4-inch lumber for the horizontal cleat to the recorded width. Dryfit the cleat inside the mantel to ensure it forms a snug fit, or trim excess around its sides.

Measure the length of the legs for the pair of vertical cleats. Cut two lengths of 2-by-4-inch lumber to the length with a saw. Position each leg cleat vertically inside the legs.

Measure the thickness of the mantel that will fall flush against the wall. Mark this measurement at different points along the pencil line on the wall. Connect the marks using a level to form a guideline for hanging the cleats.

Position the horizontal cleat against the marks on the wall. Bore four 1/2-inch-wide evenly spaced holes through this cleat and into the brick surface using a drill and masonry bit.

Replace the masonry bit with a screwdriver bit and insert 2 1/2-inch concrete screws into the holes. Repeat this process for securing the vertical cleats to the wall.

Slide the fireplace mantel over the horizontal and vertical cleats before pushing it flush against the wall. Ensure it falls directly above the pencil outline on the wall.

Drive 2-inch screws every 12 to 16 inches along the back of the mantel to secure it to the upper cleat, and through each side to secure it to the corresponding vertical cleat. Countersink the screw heads so they fall below the surrounding surface.

Cover the screw heads with wood putty. When the putty cures, cover it up with touch-up paint so it matches the surrounding surface.