Sealing the natural stone of your fireplace surround or hearth area will increase the life of the stone and make maintenance easier. The sealers protect the stone from staining and from scratches that can occur with frequent use of fireplace tools. While each sealer has its own specific set of directions, there is a general process to applying a sealer to natural stone fireplaces.
Wipe down the entire surface of the stone fireplace with a damp sponge to remove any dirt or dust. Wipe it with a lint-free towel, then let the fireplace air-dry for 12 hours.
Read all application instructions on your stone sealer before you begin applying it. Some sealers require you to spray the surface of the stone with water before applying the sealer. If your sealer requires this, fill a spray bottle with clean water and mist the surface of the stone until it is completely wet, then wait three minutes before applying the sealer.
Dampen a clean cloth with the stone sealer and begin wiping it onto the stone surface. Start at the top of the fireplace and work down towards the floor. Re-wet the cloth whenever it becomes dry. Do not form any puddles on the surface of the fireplace.
Allow the sealer to dry according to the package directions.
You can apply a combination sealer/enhancer, which will bring out the colour of the stone, or you can apply a simple sealer.