How Do You Install Stones Around a Fireplace?

Materials

• The stones you'll use to reface your fireplace are the most obvious materials you need for the project. Veneer mortar is used to attach the rocks to the fireplace face. A trowel is necessary to apply the mortar. You need builder's felt to cover the existing fireplace and metal lath to give the mortar and rocks something to stick to. A grinder tool is necessary to help you cut down stone pieces to fit. To finish the job, you need grout and a large plastic bag to direct the grout into the gaps between the stones.

Preparation

• Check the current fireplace material for any loose pieces, especially if it is a brick fireplace. Remove any lose bricks. The builder's felt should then be stapled to the fireplace so that it is flat against the old face. If you need multiple sheets of felt, position the pieces so they overlap by about 2 inches. You then cut and nail the metal lath into position with the small protrusions facing up like small cups to catch and hold the mortar. Like the felt, you want to overlap pieces by 2 inches. You also need to apply the lath to the sides of the fireplace. Apply a scratch coat of mortar, working from the top down to cover the lath and fill the cups. Continue applying mortar until it is about 1/2-inch thick. After 20 minutes, run the notched edge of the trowel horizontally across the mortar to make grooves that will help the stones stick better. This scratch coat must cure overnight or longer.

Stone Preparation

• Before you start applying the stones to the fireplace, do a trial run on the floor to see how the stones will fit together. You only want about a finger's width between stones, so you may have to try several stone combinations to find pieces that fit together well. Trim the corner pieces that wrap around as needed to fit by scoring the stone with the grinder and hitting it with a hammer to break off the excess.

Stone Application

• Start at the top when you install the stones. Dampen the back of each stone and the scratch coat on the fireplace by spritzing lightly with water. You want the mortar to be the consistency of pudding for the stone application. Spread a 1/2-inch layer to cover the back of the corner stone piece completely. Make an indentation down the middle of the mortar before pressing it firmly into position. Wiggle slightly to get the stone pressed down so it touches the scratch coat. Leave any mortar that squishes out and brush it away after it dries. Install the header pieces and corner pieces first. Continue filling in the rest of the surface. Let the mortar set overnight or longer.

Finishing

• The prepared grout goes into a grout bag with the tip cut off to make the stream of grout the same size as the gap. Squeeze the bag to get the flow of grout started so there isn't any air in it. Pull the bag upward as you fill first the vertical and then the horizontal joints. The grout should be even with the stones or stick out slightly. After letting the grout rest for an hour, use a striking tool to go back and smooth and shape the joints to create the desired look. Wait 48 hours or longer to use the fireplace.