A clean, well-maintained stone fireplace is both beautiful and functional. Many conditions affect the appearance of fireplaces, including the type of stone used, the age of the fireplace, previous sealing of the fireplace, and how well the fireplace box has been designed. The first step to cleaning any masonry fireplace is to have a professional chimney sweep remove soot, creosote and other debris from the chimney. The next step is to repair any problems with how the fireplace works or problems with the mortar and grout. Once the fireplace is sound, it is time to clean and seal it before using it again.
Things You'll Need
- Plastic sheeting
- Water bottle
- Garden sprayer (optional)
- Old towels
- Nylon brush
- Foaming bathroom cleaner
- Trisodium phosphate
- Phosphoric acid
- High-alkaline cleaner
- Grout cleanser (optional)
- Diatomaceous earth
- Bar Keepers Friend
- Distilled water
- Steam cleaner (optional)
- Protective glasses, gloves, face masks
- Stone sealer (pH neutral)
Remove all furniture, decorations and rugs near the fireplace. Spread dropcloths and plastic sheeting to protect surfaces and other areas from splatter. Tape off any wall or ceiling areas that may be splattered.
Saturate "natural" stones with water, starting at the bottom of the fireplace. Stones and grout/mortar will absorb the water and become "full." This will prevent loosened liquid dirt from absorbing (as it will with dry stones and mortar). By working from the bottom up, any dribbles that flow down will encounter wet stones and grout. Use a spray bottle or garden sprayer to apply the water. Use towel log rolls to absorb excess water where necessary.
Apply scrubbing bathroom cleanser at the top of the fireplace. Wearing protective goggles and gloves, scrub the worst stains with the bristle brush. Mop up dirty water into the bucket to keep it from running down the stones too much. Use the spritz bottle to rinse stones as you work to both keep them wet and to see your progress.
Examine the fireplace after the first pass. Trisodium phosphate or phosphoric acid can be diluted in water and applied to spots. For stains that have penetrated deeply, use a steamer and brush to loosen the stain. Try Bar Keeper's Friend or grout cleanser on grout staining (after other products are rinsed off). It is best to test this product in a hidden area first to check for color fastness of the grout. Keep it off the stones and away from any metals.
Lift stubborn stains by mixing diatomaceous earth (clay) with soapy water to form a clingy paste. Push this into the stain and cover with plastic and tape. Allow the clay to dry. The drying action will pull moist stains out of the stone. Apply this several times if necessary.
Rinse the clean stone fireplace with distilled water. Distilled water will not leave mineral deposit stains on the stone. Dry the stone work immediately with towels. Allow all moisture to dry out of the stones (this may take a few days) and apply a neutral stone and grout sealer to the fireplace.
Tips & Warnings
- Work small areas if the stone style is rugged. For faux stone fireplaces, obtain cleaning recommendations from the manufacturer before starting. Cultured or cast stones may not be colorfast and may react to chemicals in cleaning products.
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