How to Install a Shelf Mantle

Lay the shelf of the mantle face-down on the carpet in your installation room. If your room is not carpeted, lay down a tarp or area rug to prevent the flooring from scratching the shelf or vice versa.

Insert the legs of the mantle into the shelf piece. Depending on your installation kit, this may involve setting dowels in place and tightening them, or installing screws with a power drill. Follow specific product instructions regarding setting these in place.

Lift the assembled mantle against the wall above the fireplace. Adjust the location of the mantle so that it sits centered around the firebox.

Set a level on top of the shelf and make sure the mantle is level front to back as well as side to side. If necessary, install shims under the legs to bring one side up higher to achieve a perfect level. A non-level shelf is not reliable to decorate.

Trace the shape of the mantle on the wall with a pencil, creating a guide for your installation. Do not shift or move the mantle while you trace, because this is the exact guide with which your mantle will line up when you attach it.

Pull the mantle away from the wall and set it face-down on the floor. Cut a 2-by-4-inch piece of wood to the exact length of the inside of the shelf and set it in place to make sure it fits. This piece of wood is the cleat for the shelf, which helps to support its weight during installation.

Cut 2-by-4-inch pieces of wood to serve as cleats for the legs as well, cutting them to the length and depth of the legs. This gives you three separate pieces of wood to serve as support cleats.

Hold the shelf cleat up against the wall in the position corresponding to where it fit under the shelf. Drill four ½-inch pilot holes, evenly spaced out across the cleat, straight into the brick of the fireplace, using a carbide drill tip to cut through the masonry.

Insert 2 ½-inch concrete screws through the pilot holes and screw them into place. Insert the screws into the brick and not the mortar, since the mortar isn't as strong.

Repeat drilling pilot holes and installing the screws for the remaining two cleats. With all cleats in place, slide the mantle over the cleats, lining it up with the guideline you already created. Make sure the mantle is flush with the wall at all points.

Attach the mantle shelf to the cleats with 2-inch finishing screws, hammered or drilled into place every 16 inches along the back of the shelf and the outer edges of the legs.

Cover any gaps between the legs and the face of the fireplace with edge molding pieces, attached to the mantle with 4D finishing nails. If necessary, fill in the screw heads or nail holes with filler putty.