How to Stack Stone for a Fireplace Mantel

Select stones for the base layer of stone at the top of the fireplace facade. Stones need to have at least one flat surface and be of varying sizes in order to arrange the stacked mantel in a sturdy manner. Place the stones on top of the facade to test the fit. Adjust the arrangement until the stones fit on top of the facade.

Remove the stones and place them in the same order on a work surface.

Apply a thin layer of mortar to the bottom of each base layer stone using a trowel. Approximately 1/8 of an inch of mortar is adequate. Lay each stone firmly in place until the base layer is complete. Start from the back and work your way to the front edge of the mantel. Place the stones with the flattest and longest face flat against the fireplace facade.

Stack a second layer of stone by adding one stone at a time until you have completed the layer. Apply a thin layer of mortar to the bottom of each stone as you set it in place. It is important to consider placement of the second stones carefully because the joints must be staggered with the layer below. Also, be careful not to place two similarly sized stones on top of each other.

Complete the stacked stone mantel with a final layer of moderately flat field stones. Stagger the joints in the same manner as with the second layer. Apply mortar to the bottom of each stone as you stack it on top of the second layer. Press each stone firmly into place.

Wipe off any mortar that may have gotten onto the exposed surfaces of the field stone with a damp rag. Allow the mortar to set for five to seven days prior to applying any pressure to the stone mantel.