MAPEI Keracolor S sanded grout inconsistent grout color

[Foos]

Our laundry room was recently tiled and days after grouting I noticed very inconsistent grout coloring with light gray/almost white areas within the charcoal gray grout. Our tile contractor said it just needed to be cleaned with water and possibly mixture of water/vinegar. I took a sponge with just water and am not noticing any improvement. We have another room that is about to be grouted in 6 days and I would like to avoid this. I'm going to ask he fix the laundry room before continuing any further, but would like to ask advice on how to fix this.

The grout is MAPEI 47 Charcoal Keracolor S Sanded grout. Tile is set with Acrylpro. I noticed in the un-grouted room that several tiles have quite a bit of Acrylpro that squeezed up...could having limited grout area due to Acrylpro build up cause this?

[cx]

What size are those tiles, Scott?

How long after setting were they grouted?

This the same contractor who did the very questionable job on your shower?

[Foos]

These are 12x24 tiles. It was grouted the day after it was set, so about 24 hours. This is the same contractor (I wasn't sure if I should start a new thread for this or continue the other)...this tile job was happening in parallel to the shower job along with a backsplash in the kitchen...I had the floor covered in RAM board for the last 2 weeks to protect and just uncovered it to try to clean it.

[Tool Guy - Kg]

Take a look at these directions from AcrylPro.

The very first limitation to the product listed is at the top of the page:

Limitations to the Product
Recommended floor tile size: 8" (20 cm) or less on all sides.

So, while the wet mastic (I can say for centainty that the mastic was not dried within 1 day) indeed plays games with the color of the grout (and is also a common complaint with inexpensive grouts such as this), the point is kind of over-ridden by the fundamental mistake of using this product incorrectly. I'm very sorry to tell you that the product is not likely to dry anytime soon. Such a mistake is fixed by replacing the products with a setting material that is approved for such an installation. When paying a professional to install this, they are expected to a a workman like job and not use inappropriate materials like this. I would demand a replacement of the tile, setting material, and substrate to correct said mistake.

P.S. It also appears from the photo that they may have neglected to leave a 1/4" gap between the tile and the wall board.

[Kman]

I bet if the tile was set over concrete you could carefully pull each piece up and clean the backs with a water hose. I fixed a job like this one a few years back where it was set over vinyl. Only an inch or so around the perimeter of the tile had (somewhat) dried mastic in it.

If it's over a cement board you may break a few tiles trying to remove them. The only way to know for sure is to start removing them. And the sooner the better.

Sorry for the bad news.

[Foos]

Correction, sorry about mistake...it was Schluter All Set used and not AcrylPro. I forgot they applied a Schluter membrane on this floor with All Set, then another layer of All Set and tile.

Agreed, in both rooms tiled they neglected to leave much (or any) gap between the wall and tile.

[MAPEI - Technical Service]

Hey there Scott!

Sorry to see the color inconsistencies you are having with Keracolor S.
To your point of seeing setting material in the ungrouted joints in the other area, that can definitely affect the final color of the grout if not removed. Before the crew grouts that second space, I would have them get those spots cleaned out so the joint is empty and free (or at least a consistent depth at least 2/3 the depth of the joint). As the grout dries and cures, any areas where it is thicker or thinner can affect the final color.

Otherwise, inconsistencies in portland cement grouts like Keracolor S, can occur due to a wide variety of reasons. To avoid typing out an entire novella, instead I'll lead you to our Grout Troubleshooting Guide here:

https://cdnmedia.mapei.com/docs/libr...sn=376da9bf_56

Please feel free to reach out if you need anything else!

[Kman]

Big difference between those two setting materials!!

So I'll echo what Holden says about the excess mortar in the joints. Have those cleaned out and vacuumed before grouting.

Next, I would probably grab a few gallons of distilled water for the next batch of grout. Enough for mixing and cleaning.