Dark Grout Turning Light [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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02-01-2010, 07:44 AM
I installed a grey grout on porcelain tile on Saturday which is turning light colored as it dries. The grout is TEC - Accucolor Premium (sanded portland cement, polymer-enhanced). I mixed the grout properly and in accordance with the directions.

I have cleaned it with a 50-50 water/vinegar mix trying to remove the light coating to no avail. It looks the proper color when wet, but as it slowly dries, the light color returns.

The package warns against the potential for efflorescense and to use the TEC product "Like New" it happens. Is this the right approach?

Your advice is appreciated. See photo below.


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02-01-2010, 09:07 AM
Scrape the surface to see if the grout color below it is correct. If so, a acid scrub will help. However, if the color is consistant through out, then you won't get any help with the TEC product.

02-01-2010, 09:48 AM
I scraped a small area of the grout surface and the proper color is below the surface.

02-01-2010, 01:05 PM
I met with the tile supplier today and he believes that I was too liberal with the tile washing and washed the grout's color pigment away. I can buy that as the tile is textured and took some work to remove the grout. He recommended that I use an AquaMix tile colorant which I will probably do tonight. My frustration level is high after carefully selecting the perfect tile matching grout only to have to "paint" the grout to make it look respectable.

02-01-2010, 01:40 PM
I'd use the colorant only after trying to scrub the top layer off with a stronger acid than vinegar and water. The TEC "Like New" is a stronger acid than vinegar, but may not be as stong as sulfamic acid.

In either case, let the acid dwell on the grout for a few minutes, agitate with a synthetic bristle brush and let dwell some more, then rinse. It still may take a couple applications.

Tool Guy - Kg
02-01-2010, 01:46 PM
Welcome to the forum, Johnson. :wave:

I wouldn't be too quick on painting that grout. Grout drying lighter than expected is a very, very common complaint. And a lot of pros who practically ruin their wrists twisting their sponges as dry as possible are given the standard industry response to light grout of, "you used too much water". While it may be true in your case....maybe it's not.

I'd wash it with vinegar (or escalate to something stronger like sulfamic acid), let it dwell for a minute or so, then scrub it with a nylon bristle brush a bit and rinse it off (use a wet vac if you have one). Rinse it a second time with water to neutralize the acidity and allow it to dry. Inspect to see if you have an improvement.

Time for some patience...
You only grouted two days ago and it's not cured enough to be attacking it with an acid like this. So wait 'til this weekend before performing a test in an small, inconspicuous area. If you have your results you're looking for, proceed with the remainder of the project. :)