Uneven Grout Color [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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08-05-2002, 08:28 PM
Hi all,

My husband and I just grouted our ceramic tile floor, and we have uneven grout color. We can't figure out why. We bought a colored grout called Antique White. We had a 25lb bag, and used one batch for the entire floor. We mixed the grout powder with distilled water, and mixed it very well with an attachment on our drill. It's been 9 days since application, and the grout is much darker in some places. Can anyone tell me what may have happened here? There's no pattern to the darkness that I can tell--it's like, random. It's really wierd and both HomeDepot and Lowes looked at me like I had three heads when I asked about it. We bought the grout at HomeDepot.



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Rob Z
08-05-2002, 09:16 PM
Hi Gina, and welcome

Several things could be the cause of the mottled grout color, but the most likely may be :

1. Too much water used during clean up.
2. Uneven depth of grout in joints, caused by thinset that oozed up in the grout joints.
3. Grouting too soon after setting the tile.

Did you clean the joints of excess thinset before grouting?

Did you use a well-wrung sponge during clean up, with a minimum of water getting on the grout?

How long was the tile set before grouting?

Answers to these questions may help determine a solution.

08-05-2002, 09:24 PM
Hi Rob! Thanks for stopping in :)

In answer to your questions:

>Did you clean the joints of excess
>thinset before grouting?

Yup. Anything that oozed up got scooped out with a spacer prong as I went (it was handy). I got a shop vac and got any dust and debris out as well. I wouldn't say the grout is perfectly the same depth all over. The adhesive was lower than the spacer could get in some places.

> Did you use a well-wrung sponge during
> clean up, with a minimum of water getting
> on the grout?

Yes, well wrung--though I did use the sponge to tool the grout after my fingertip went through it. I did that to every joint.

> How long was the tile set before grouting?

Um...at least 4 days, could've been a couple days longer than that.

Hubby and I are complete beginners. I was thrilled with the application until the grout, and I'm pretty bummed about it. :( Thanks for input!

BTW, after knowing the probable cause, how do i fix it?

08-06-2002, 09:46 AM
Gina, what brand is your grout? I had a similar problem with antique white and mine was done by a professional not me.

08-06-2002, 09:59 AM
We bought our grout at HomeDepot, it was Custom Building Products PolyBlend Sanded, Antique White.

John Bridge
08-06-2002, 03:35 PM
Hi Gina,

With super dense tiles, grouting is always a challenge. It's very hard to control the amount of water left in the joints.

I would suggest you scratch the surface of a joint where the grout is discolored. You may find the discoloration is only on the very surface. If this is the case, you can clean it off with a mild acid. Start with white vinegar mixed half and half with water. If that doesn't work, we've got some stroger stuff. :)

08-20-2002, 02:48 PM
John, sorry about the long dealy in this, had some other stuff going on in life :-P I tried your suggestion. First, I scratched the surface, and it didn't look any different, so I tried the white vinegar and water solution. I used a dry white rag and dipped it into the solution, then rubbed it over the grout. I let it dry for a couple of minutes but I couldn't stand it and used a hair dryer on it to see what happened.

I don't see any difference :(

What do I do now? I'm mystified on why this happened!

John Bridge
08-20-2002, 03:44 PM
Hi Gina,

I don't know what happened either. :)

If the discoloration goes down into the depths of the grout, I would suggest using a grout colorant over the surface of the joints. Sounds like the floor is not too large, since you used only one sack of grout.

The Aquamix grout colorants hold up 10 years or maybe longer, depending on how much abuse the floor recieves. That's the way I would do it, otherwise, it's a case of removing the grout, and you don't want to go there.


08-20-2002, 03:57 PM
Ya know, I've looked into that grout colorant already, and here's my dilemma--I can't *find* it anywhere! I looked at their dealer locator, and neither Lowes nor Home Depot carries it (near me anyway), I tried a local tile store that was listed, who said they could get it, but didn't carry it in stock. Aquamix doesn't have a color chart on their site. Is there a place online that I could order it or see color charts?

Do you know if the Aquamix Antique White colorant would be close to what my HomeDepot Antique White grout is supposed to be?

John Bridge
08-20-2002, 04:21 PM
I've scanned the color chart but don't know how good it will be via the Internet. I have the Custom grout color chart also, and to me, they look close. The Aquamix chart is not that high-quality to begin with.

Where do you live?


Let's all start bitching at KW for a better quality chart. It's his responsibility after all. ;)

08-20-2002, 04:43 PM
Aquamix will match any colour you want. Tell your local supplier what the brand and colour you want to match, and aquamix will sent it to them. They told me they match 60 different companies colours..so I'm sure custom is on their list.

08-20-2002, 04:47 PM
I live in a suburb of Cincinnati, Ohio (Batavia). I can't drive too far due to an illness, so I'm kinda stuck around my local area unfortunately. From the looks of the color chart (yeah, it is hard to tell on the internet because of the different monitor calibrations we might have, etc), the White (which looks kinda cream to me in the scan), Antique White, or Linen White would be the span I'm going for here. I'd probably have to test them in real life to see the results. That's why I was hoping to find a dealer that carried them so I could take back the ones I don't use.

08-20-2002, 04:50 PM
Hey, thanks Bri! I had no idea they'd color match. Problem is, since the durn grout turned all different colors, I'm not sure what "Antique White" is actually which color on the floor! LOL! But I'll ask whoever I find about it. Thanks!

08-20-2002, 04:59 PM
I just called Custom Building Products, as I'm pretty hopping mad about all this and asked them what the heck I did for this to happen :)

They said it was probably mineral deposits that came up through the grout, and to use Sulfamic Acid to clean the grout. I told them I used distilled water, but that was their only answer except for grout colorant. Sigh.

So, can ya get sulfamic acid online??? :-P

John Bridge
08-20-2002, 05:21 PM
You can get sulfamic just about anywhere, but if the problem is below the surface, it's not going to help. Sulfamic is sold in crystal form. You add the crystals to water and they dissolve. You can't over-concentrate it, so it's faily safe.

Once again, though. You've scratched down and determined the blemishes are deep. Sulfamic won't help.

08-20-2002, 05:43 PM

Let's go back to John's original recommendation of cleaning with vinegar and water. This solution will help when used correctly. Prewet floor with plain water. Apply liberal amount of vinegar/water solution (should puddle in grout joints. Let dwell for 5 to 10 mins. while scrubbing with short stiff brush. Remove with wet vac. Rinse with water and repeat with wet vac. Allow to air dry (no hairdryer).
This will remove any surface latents and will probabley look more even.For the next few days wet the floor down with a liberal amout of water(joints should stay wet for at least 45 minutes) This damp curing will even out the color. One reason your grout is mottled, may be due to uneven cure.
Well worth the try before colorant.

John, the chart you posted is the chart on the back of a bochure. The "real" chart is very high quality and is a stand alone piece. :)

hope this helps

08-20-2002, 05:45 PM
Plus you're going to have to seal those joints anyway(since it's white)..so you might as well do it with the colorant?;)