Refacing an Old Fireplace With River Rock

Spread a thin layer of thin-set mortar over the existing fireplace with the flat edge of the trowel. Even out any ridges or dips to create a flat surface and let the mortar dry overnight.

Measure the fireplace surround with a measuring tape and lay out an area on the floor of equal size. Spread out the sheets of river stone and practice laying them together to see how they will fit. Trim the sheets with a razor blade to fit the surround and remove loose stones at the edges and set them aside.

Spread another layer of thin-set mortar on the fireplace and press each sheet of river rocks into the mortar. Wiggle the sheets together until you cannot see the joint between two sheets. At the edges of the fireplace, take the loose stones you removed earlier and line the up to make a clean edge for the design. Let the mortar dry overnight.

Apply grout to the stones so that the finished rocks just crest up out of the rocks. This will require multiple passes with grout over the rocks. Spread the grout with a sponge for the most flexibility. Wet down the sponge and wipe the surface of the stones clean of grout when finished.