Grouting White Marble with Black (Charcoal) Grout


I just installed a 12x12 marble (polished) checkerboard (white and black) tile in my laundry room. The wife wants black grout (charcoal). Will this penetrate into the white marble? I used white thinset and plan on using unsanded black grout. I obviously do not want to do this if it will bleed into the white. Any help would be greatly appreciated.


Contrary to what you often read/hear about marble... it is not very porous and does not stain easy... common misconception that it does.

However, the marble tile edges will be more porous than a polished face and the black grout could bleed and cause some discoloration to the white tiles since it will be in contact with the marble and wet for quite a while before curing.

This can occur when using a darker colored thinset too.

But using a lighter colored grout may not be the answer since it could also bleed into the black tiles making the edges look foggy.

And a light colored grout will show dirt way more than the dark grout.

The most effective way to combat this potential problem is to seal the marble tile edges before applying the grout.

If the tiles are polished, then the face most likely will not need (nor will it take or be able to absorb) a sealer.

Polished marble is nearly non-absorbent and rarely needs sealing. All you need to do though is water test the marble.

The unpolished edges though will be more absorbent and should take a sealer. We suggest using these recommended marble & granite sealers.

You must take care not to let any sealer residue remain or dry on the face (if polished) or it will leave a streaky haze that will require stripping.

You could also simply perform a test with some left over tiles. Set them on a level surface (piece of plywood, etc.) and apply the grout. Let sit for a couple days and see if any absorption/discoloration occurs.

Comments for Grouting White Marble with Black (Charcoal) Grout

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Yes It Stains
by: Anonymous

We installed a basketweave white w/ black dot polished marble floor.

We tested black epoxy grout which isn't supposed to bleed at all but it did. Turned our white marble to grey after just an hour or two.

We settled on a grey epoxy grout which didn't have such a drastic effect on the tile but still did bleed. The bleeding wasn't uniform so it has some dingy spots.

Don't have a solution for you, just a word of caution. Dark grout (both cement and epoxy) will bleed into white marble.

Thank you
by: Anonymous

great information. Would Mapei Grout Refresh Grout Colorant work to change the grout to black?

==== Comment: Yes, I believe that would work, but you should contact Mapei to get complete product use information.

Grouting white marble mosaic bathroom floor
by: Anonymous

I am restoring a 1920's white marble mosaic bathroom floor; I am considering re-grouting in black but want to make certain of any necessary precautions/steps to avoid possible staining.

===== Admin Comment:

You'll want to water test the marble to see how absorbent it is first.

Test the edges as well. If absorbent, then yes you'll want to seal the tiles and edges prior to grouting.

If possible (with some unused tiles) run a test by setting a few of the marble mosaic tiles on wood or some other temporary surface and grout this "sample" section. Note if you get any bleeding of the color.

If not and/or if testing shows low absorbency, then you may be fine not sealing the mosaic tiles.

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