The challenge is to mount a fireplace mantel to the wall without putting screws or nails through the fireplace mantel wood. The solution is a French cleat. French cleats will allow you to remove the mantel, if needed. The French cleat is made using a piece of wood, cut so each section interlocks with the other. One section is mounted to the wall and the other on the back of the mantel.

To make the French cleat, take one piece of lumber and using a table saw rip the board lengthwise. Before cutting, set the table saw blade at 45 degrees. These two pieces will interlock when mounted.

Attach the piece to the wall so that the angle slopes back towards the wall. The chisel point will face up and out. The piece on the mantel and the chisel point facing down and out. When one section is placed on top of the other, they can not pull forward. The mantel will be mounted to the wall with no mounting screws or nails being seen.