How to Install a Heavy Wood Mantel Shelf

Updated February 21, 2017

A fireplace adds comfort and warmth to a room, but a firebox without a mantel sometimes looks too plain. For this reason, most fireplaces feature mantel shelves that hold decorations and family photos. The mantels are generally made of wood, and installation can be tricky, since the wood pieces can be heavy. Installing supports helps the fixture last longer.

Lay down a protective tarp to protect your flooring from the heavy wood. Place the mantel shelf top-down onto the tarp, exposing the holes for the legs.

Connect the legs to the mantel shelf. Most mantel kits include shelves and legs with pre-drilled holes and installed dowels. Lock the dowels securely in place.

Lift the mantel and place it against the wallt. Center it around your fireplace in the position in which you will install it.

Run a level against the wall to check for flatness, as well as front to back across the shelf. If necessary, install thin wooden shims between the legs and the floor to bring the surfaces level.

Trace the outline of the mantel's intended position against the wall in pencil. This will help you install the supports for the heavy wood.

Lift the mantel out of place and place it facedown and top-down on the tarp. Measure the width of the shelf from the inside and back with a tape measure and cut a two-by-four-inch piece of wood to this length with a circular saw or table saw. Fit the cleat into place on the inside of the shelf to check the fit.

Measure the length and depth of the legs from behind and cut two-by-four pieces to match these as well. Fit them inside the legs to check the fit. These two-by-four pieces, known as cleats, will provide extra support for the heavy mantel, taking some of the stress off of the wall and the screws that hold the mantel in place.

Hold the shelf cleat against the wall, inside the outline where it corresponds to the actual shelf position. Drill four ½-inch holes through the cleat, spaced evenly apart, with a carbide-tipped masonry drill bit. The holes should extend into the brick or wall of your fireplace.

Install 2½-inch long concrete screws into the pilot holes in the clea, using a drill. This will secure the top cleat to the wall. Repeat the process with the leg cleats as well to install all support pieces.

Lift the mantel and fit it into place over the cleats, lining it up with your outline on the wall. Press the mantel firmly against the wall and install 2-inch finishing screws into the mantel every 16 inches along the shelf. The screws will go into the cleat, securing the shelf in place.

Install finishing screws every 16 inches along the outer edges of the legs to secure the mantel to the leg cleats. This will secure the mantel in place.

Hammer thin pieces of moulding and 4d finishing nails into place along the inner edge of the mantel if necessary to hide gaps between the leg pieces and the brick. Use filler putty to cover screw and nail holes.


If you intend to paint the mantel, prepare and apply the first coats before you assemble the pieces. You can complete the final coat once the mantel is installed.


Do not attempt to lift the pieces or the constructed mantel yourself if they are too heavy for you. Always use assistance when working with heavy objects.

Things You'll Need

  • Tarp
  • Mantel pieces
  • Level
  • Shims
  • Pencil
  • Measuring tape
  • 2-by-4-inch lumber
  • Circular saw or table saw
  • Drill
  • Carbide-tipped masonry drill bit
  • 2½-inch-long concrete screws
  • 2-inch finishing screws
  • Hammer
  • Finishing nails
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About the Author

Samantha Volz has been involved in journalistic and informative writing for over eight years. She holds a bachelor's degree in English literature from Lycoming College, Williamsport, Pennsylvania, with a minor in European history. In college she was editor-in-chief of the student newspaper and completed a professional internship with the "Williamsport Sun-Gazette," serving as a full-time reporter. She resides in Horsham, Pennsylvania.