How to Hang Stone on Fireplaces

Clean your fireplace with an all-purpose cleaner and degreaser safe for a porous surface. Scrub the surface of the fireplace with a nylon scrub brush, removing dirt and loose debris.

Attach galvanized metal lath with galvanized nails or 3/8-inch double point hammer in staples to a wood fireplace surround. Hammer the nails or staples into the wood surround randomly to keep the metal lath tight and flat. Inspect the metal lath for any places that are loose and add additional staples or nails to the loose area. Attaching metal lath is not required on a brick fireplace.

Lay the stone out on the floor in the pattern you want to replicate on the fireplace. Check the positioning of the stones to ensure that you have them positioned to cover your existing surround. Do not make any cuts in the stones until you are ready to install them.

Mix Type "S" mortar mix in a bucket with a margin trowel following the directions printed on the product.

Apply a 1/4-inch of the Type "S" mortar to the metal lath with the margin trowel on the wood fireplace to create a scratch coat. The scratch coat provides a rough, solid surface to hang your stones on.

Brush the surface of the scratch coat lightly with a medium-bristle scrub brush to roughen its surface while the mortar is wet. Do not apply extra pressure to the brush as you could accidently brush too much mortar from the scratch coat. Allow the scratch coat to dry before applying your stones. It is not necessary to apply a scratch coat to a brick fireplace surround.

Apply the corner stones to your fireplace surround first. Make any cuts necessary to your stones with a circular saw or grinder with a masonry or diamond blade. Start at the top of your fireplace and work down to the floor; alternate from one side of the fireplace to the other. Butter the back of each stone with 1/2-inch of Type "S" mortar mix using the margin trowel.

Push the stones against the fireplace with a slight twisting movement until some of the mortar squeezes from behind the stone. Hold the stone in position for four or five seconds to ensure that the stone sticks to the surface when you let go. If your design includes a grout line between your stones, remember to leave a space between each stone at the width you desire.

Remove any excess mortar from around the stone and any from the surface with a damp rag. Do not continue to move the stone or attempt to remove it from the fireplace. If you must remove the stone, scrape the mortar from the surface and the back of the stone to start over.

Complete the hanging of the stone on your fireplace, keeping each stone clean of excess mortar. Let the mortar dry for the suggested time printed on the Type "S" mortar's directions. The average drying time is about one hour.

Mix a batch of Type "N" mortar in a bucket according to the directions on the product.

Cut the tip from a grout bag, then fill the bag with the mortar mix. Squeeze the bag over the grout bucket to remove any possible air pockets.

Apply the grout to your desired depth into the spaces around the stones. Depending on the type of stone you hang on your fireplace, you may not need to install grout.