Epoxy Grout for River Rock?

16 years ago

My tile installer has installed my shower walls with white field tile and glass mosiac. I looks fabulous! He has also finished installing the marble on my floor and it looks equally as great. For the shower floor, I have river rock. He said that although he loves the look, he thinks there is potential for mold to grow on the grout/stones because the water may pool between the stones when it cannot find it's way to the drain. My husband I talked it over and decided to go with the stones anyway so he installed them and said we should definitely pay up to use epoxy grout for the job. So my question is, were we stupid to go with the stones? Is there potential for mold and how should we care for the floor? Also, what about the epoxy grout? Do you agree that it's the best way to go?

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sassyinak

16 years ago

I have regular sanded grout in my river rock shower floor. Although there is a small amount of pooling, I have not had a mold problem. I do try to soak up the excess water with a sponge or towel if I have time. Although I can't answer your specific question regarding epoxy, I believe there are microbial inhibiting additives that can be used with regular grout to help with this problem. I think the stones look fabulous, and worth the extra little bit of extra work to dry them. I would recommend that you get the ones that are cut flat on the top. This makes them easier to install and promotes drainage. The flat ones didn't come in the color I wanted, so mine are a bit rounded, but be sure to look for the flat ones.-Sassy

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Comments (12)

novice_from__ct
Original Author
16 years ago
I also have the more rounded rock, not the flat top kind. I'm glad you're not seeing any mold. I will have to find out about those additives. That sounds promising. What color grout did you go with? My rocks are in the tan/grey family so I'm leaning towards an "almond" color
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sassyinak
16 years ago
I used buttercream grout to go with my amber river rock. It gives some contrast, and keeps it light without being white.
bill_vincent
16 years ago
If you go with Laticrete or Mapei, or if you use TEC and mix the grout with their grout additive, the grout will have antimicrobial agents in it to fight against mold. From the way you're descibing it, it sounds like your guy is looking for the upcharge.
novice_from__ct
Original Author
16 years ago
Hi Bill, does Laticrete already have the antimicrobial agent in it or do I have to add it separately? My tiler asked that if I want to Epoxy that I pick it up on my own so there is no upcharge. Maybe he's just extra cautious?
mahatmacat1
16 years ago
One thing I learned about epoxy grouting river rock: you want to make sure a line is left at the edge for caulk (color matched) to be put in right at the plane change, or you risk cracking at the seams (I've heard of regular tile breaking, rather than the epoxy grout breaking, but in our case, I guess the rocks were flexible enough that the epoxy grout cracked instead).

It's a bit tricky aesthetics-wise, because there's no natural break as there would be with a row of tile--we're just cutting a teeny groutline-sized line in and we've made sure to color-match the caulk to the grout very carefully.

The lack of natural break with the rocks is why mongo has shown that he puts a row of tile around the outer edge of the floor of a rock shower--it provides you with a clear place to do the caulk plane change. But if you've already got the rock down, and no ability to edgeit, just make sure that there's a groutline's worth of space left around the outside and that caulk is put in there, rather than grouting all the way up to the beginning of the vertical.
novice_from__ct
Original Author
16 years ago
Thanks for the suggestion. I will defintiely let my tile guy know to leave room for the caulk. The rocks are already down and I noticed that one rock, right in the middle of the floor, is fatter than the others and I think will be uncomfortable on my feet. Is it too late to remove that rock and replace it with what's left over since the rock is already fastened to the floor?
bill_vincent
16 years ago
The Laticrete grout already has the agent in it.
novice_from__ct
Original Author
16 years ago
Thanks Bill. I've posted pictures of the installation so far. I'm concerned that he isntalled the rocks before finishing the shower walls. Is that going to be a problem?

Here is a link that might be useful: Master Bath
bill_vincent
16 years ago
Not if he covers it as he's working. Why he did that, I have no idea. One way or another, let him know if it IS a problem, it'll be HIS problem, not yours.
mahatmacat1
16 years ago
just wanted to say I LOVE your glass tile accent! Where did you get it? It's fabulous.

And you also might (if possible) want to ask if some of the stones on the edges of the lines could be adjusted (it might well be too late now, but maybe not?) so that the break between units isn't so clear? Just a thought.
novice_from__ct
Original Author
16 years ago
Thanks flyleft. The tile is from Oceanside glass tile. It's from their Facets line and is called Marquis. I really do love it. The color is Sandstone. It's pricey so we had to use is sparingly. We are gong to use it as the backsplash on our vanity as well.

I will talk to the tile setter about making any adjustments. I really have no idea if they can move any of the rock now. We have that issue with the rock that is sticking up a bit from the others which I definitely want addressed. I guess I'll find out more tomorrow.

Here is a link that might be useful: Oceanside Tile