How to Grout a Stone Fireplace
Grouting a standard tile surface is a simple matter of wiping the grout over the whole tile field, scraping it off the tile face and pressing it into the spaces between the tiles, then wiping down the surface with a sponge. This won't work for some grouting projects, however. If you're grouting a stone fireplace or other surface that's porous and/or very textured, it's too difficult to get the grout off the surface. Those projects call for a more targeted approach, using a grout bag to put the grout only in the spaces. Does this Spark an idea?
Things You'll Need
- Bucket
- Wide putty knife
- Rubber spatula
- Grout bag (canvas tube, looks like a large pastry bag)
- Sponge
- Soft-bristled hand broom
Instructions
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1
Mortar the stones in place, leaving between 3/8 and 1/2 inch between them. Let them set for at least 24 hours.
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2
Put an inch or so of water in the bottom of a bucket. Add enough grout to cover it. Mix with a putty knife. Add more grout and water, alternately, until there is about a half gallon of grout with the consistency of thick mud.
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3
Let the grout sit in the bucket for 10 minutes. (This process, called "slaking,'' melds and softens the different elements in the grout.) Re-stir it. Pour it into the grout bag, pushing it in with your rubber spatula. Fill the bag and close the top.
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4
Set the tip of the grout bag into one of the spaces between the fireplace stones. Squeeze the bag from the top to expel grout while pulling the bag backward. Adjust the speed of the movement with the pressure on the bag so that grout completely fills each line but doesn't come out over the top and onto the stone. Grout all the spaces.
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5
Go over each newly grouted line with a damp sponge, using the edge of the sponge to flatten and smooth the grout and take off any stray grout that's gotten the surface of the stone.
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6
Let the grout set for about an hour, then go over the surface gently with a soft-bristled hand broom to bush away any surface debris and give a slightly textured look to the grout.
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Tips & Warnings
Wear a dust mask when mixing your grout.