How to Cover a Brick Fireplace With Rock Veneer

Clean the bricks of the fireplace with warm soapy water using a scrub brush to remove any dirt or soot. Rinse the bricks with clean water and pat the surface dry with cloth.

Cover the bricks with 18-gauge metal lathe. Nail the lathe into place using 2-inch masonry nails placed every 6 inches. Overlap the lathe when two pieces meet. Use a 2-inch overlap for horizontal meetings and a 6-inch overlap for vertical meetings. Cut the lathe when needed with tin snips.

Mix a batch of mortar in a large bucket using two parts sand and one part Portland cement. Add water, mixing steadily with an electric drill with a paddle bit attachment until the mix reaches a spreadable constituency. Spread a thin layer of mortar to the lathe using a trowel. Push the mortar through the lathe onto the brick until you've covered the metal of the lathe completely. Scratch the surface of the spread mortar with a mason's scratcher to create a scratched texture. Wait 48 hours for the mortar to dry.

Measure the fireplace surfaces with a tape measure to determine the placement of the stone veneer pieces. Set up the veneer pieces on the floor for each fireplace side. Leave sufficient space between veneer pieces to match any grout or mortar lines incorporated into the veneer design. Make any marks on the stones with chalk for cutting necessary to fit the stones into place.

Cut the stone to fit using the marked lines as guides. Use a wet saw to cut the stone veneer to decrease the amount of dust created from the cutting. Rent a wet saw from a home improvement store or equipment rental shop. Wear work gloves and safety goggles when cutting for protection from flying stone chips.

Mix a second batch of mortar in the bucket. Cover the first mortar layer with a second layer of the material 1/2-inch thick. Use the flat of a notched trowel to spread the mortar in an even layer. Tilt the trowel to a 45-degree angle and go over the mortar with the notched edge to raise a series of ridges that will apply a more even coating on the rear of the stones than a flat mortar surface. Cover only a section of the surface at a time to avoid the mortar's drying as you apply the veneer. Start from the top of the face of the fireplace and work your way down. Do the fireplace sides.

Mount the veneer to the fireplace, pressing it firmly into the spread mortar. Use a small wiggling motion as you set the stone into place to smear the ridged mortar a bit onto the stone rear. Follow your preset pattern to ensure that the stones fit properly, providing full coverage of the wall. Place the veneer stones onto the wall beginning at the top and working downward. Apply the stones to the mortar with a firm pressure, using a slight twisting motion to set the pieces into their final position. Maintain the gap set in the setup phase between mortar pieces to match the simulated mortar gap in the veneer pieces. Wait an hour for the mortar to begin to dry.

Fill the gaps between veneer pieces with the mixed mortar used to secure the stones in place. Add mortar to the spaces between the stones on the veneer pieces as well. Unlike grout, the mortar does not have to reach the surface of the stones but should be somewhat recessed, though of an even depth across the fireplace surface. Remove any excess mortar from stone surfaces with a damp cloth to prevent its hardening on the stone faces. Wait two hours for the mortar to harden slightly and then level out all the mortar between the stones using a striking tool. Allow the mortar holding the stones in place three weeks to set.

Seal the surface of the stones by brushing the stones and mortar alike with a stone sealant. Wait 48 hours after sealing for use.