Limestone tile install looking bad

[Morgan5210]

Hello! I just had this limestone tile installed in a laundry room and it looks spotty. I have beautiful limestone for our bathroom walls and floors and am now afraid to have it installed by the same method. The installer said it should look better when it dries, but it does not. Is the stone reacting to something he is using? Nice guy but doesn’t seem to know why this is happening…

[Davy]

Welcome Morgan. What product did he stick it down with? Also, what substrate is under the Limestone? I've seen it take 2 months for thinset moisture to dry out completely over a concrete slab and membrane.

[Dave Gobis]

Looks like spot bonding.

[John Bridge]

Hi Morgan,

Spot bonding is when the installer more or less places gobs of adhesive on the backs of the tiles and then pushes them onto the floor.

Whatever the case, limestone is often very porous and will show water through the material like that. It sometimes takes quite a bit of time for all the moisture to escape from under the tiles. it's hard for us to guess here. We need to know what method the installer used.

[Catmandu]

The big white circle looks to be exactly where the white bucket is sitting, and there's an overlapping circle next to it so guessing the bucket was moved around.

[Morgan5210]

It would have gone down just like this. Hardie backer and I’m not sure the material or method (just a designer here, not an installer).

[jadnashua]

Well, it appears that they did not read the installation instructions...they call for alkali resistant mesh tape along each seam, and it doesn't appear they put the required number of fasteners down, either.

Also note that a natural stone REQUIRES two layers of subflooring, properly installed and a twice as stiff structure (joists) than ceramic tile. Note, it's unusual for a floor to support that stiffness unless it was originally built for stone tile, so would typically require beefing up the structure before a successful stone tile installation.

I've seen stone tile take more than two weeks to dry...note, the cement cures regardless in a fairly consistent time, but that does not mean it might not already be strong.

[Morgan5210]

Thanks Jim! Do you think the splotches will come out of this floor as it dries? It’s been less than a week. The installer said maybe sealing it would help..

[jadnashua]

Probably...I'd put a fan in there, or maybe a dehumidifier, but being heating season, it may be dry enough, and just a fan may provide an advantage.

I'd be more worried about the lack of tape on the seams, the dearth of fasteners, or the potentially inadequate structure to support the stone tile.

[cx]

I'll add to Jim's "more worried" list, the likelihood that with all the other slights, he likely didn't bed the CBU in thinset mortar as required by the product manufacturer. A very high-risk installation if true.

My opinion; worth price charged.

[Davy]

The floor I mentioned in post two had Auqa Defense over concrete. That's an anti-fracture membrane that is waterproof. With the membrane, all the moisture had to leave thru the Limestone. That's why it took two months to dry out. I remember being surprised it took that long. I would think your floor would dry out quicker if you have the heat on.

I have the same concerns about the tape and likely missing thinset under the Hardi. You might ask the installer about that.

[Morgan5210]

Thanks so much for this info.

Here is the material that was used to put the tile down.

[jadnashua]

http://www.cusatraining.com/sitebuil...nails%2Cspaced is the installation instructions for Durock, which I think is what you have there. It requires the tape one the seams, and fasteners at 8" OC. Neither of those appear to be the case, nor is the nominal gap between the panels, and we can't see if an appropriate material was used underneath the panels...

[Morgan5210]

This is what was used

[cx]

Nothing wrong with that thinset mortar, Morgan, but the bag says it's white and the mortar in your floor picture is gray. You sure that's what's being used?

Just as you mentioned "Hardie backer" and the photo shows Durock. More than one floor in progress here, perhaps?

My opinion; worth price charged.