Grout SOS! I need help! My Black grout is gray!

[Josh Clark]

OK, I need some constructive instruction. I did a polished slate floor in herringbone, and wanted Black grout to accent the colors in the floor. Well I’m having problems with efflorescence/gray grout. I know I really screwed up by using to much water to clean the tile, I don’t know how I could have avoided it tho. The tiles are 3”X12” and the amount of cleaning was unavoidable. I have done black grout before this and did not have this problem. I used Mapei un-sanded grout.

I’m not a fan of how the Mapei grout refresh looks or feels, so I’m not a big fan of that solution. And using an acid to clean the grout with not work with the natural stone. So what can I do to fix this with out completely removing all my grout, which I do not want to do(because I would have to polish and reseal the tile before grout again)? Do I have any other options?

 

[One Day]

First try warm water and a nail brush to scrub off any surface salts. Let it dry and in nine out of ten cases it'll fix it.
Failing that, you could use a water based sealer such as universeal stone sealer which will enhance the grout without over enhancing the stone.
Acid cleaner is a really bad idea as you'll just completely ruin the grout.

 

[One Day]

Even olive oil, brushed into the grout will work, but not forever (if you know what I mean!)

 

[Josh Clark]

So the sealer being water based will help. Because I did forget to mention that I did try using a sealer/impregnator on a spot that would be under the vanity but it just went gray after it dried.

 

[Josh Clark]

And this is for my personal bathroom so I would like a permanent fix. The olive oil doesn’t really sound like a good idea, I’m going to be sealing the floor again and don’t want to have this problem After.

 

[Andy Allen]

Use a grout colourant.

 

[Qwerty]

As @Andy Allen says, something like Mapei Fuga Fresca will work or try a stone friendly cement residue/ efflouresence remover. I keep a non acid based cleaner on the van for this very problem

 

[Unused Account 1]

Hard to get a blck grout ,where this doesnt happen ,even a little bit

 

[bsc ceramics]

Use a grout colourant.

Iv used a black colourant before from universeal sealants. I was impressed with it.

 

[Bopster]

I’ve just used Bal ebony on black quartz tiles and after reading about it being a pain for this reason. As it happened I wasn’t bad at all, I didn’t use much water when cleaning and had no issues after buffed up the tiles.
I would try grout colourant though in this case as heard go things about it