Grouting Natural Stones

Solrac22

I am trying to re grout natural stones on a shower floor. I had completed the job but somehow water got under the stones and into the thinset and loosened a section of stones. I removed them dried it out, and reset the stones. I haven't regrouted yet and wanted to see if anyone had suggestions on keeping it water tight. Should I caulk around drain?

Ron6519

What is the construction of this shower base. You can't be directed to a solution without knowing what you did on the base.
Ron

Solrac22

Sorry about that. I used the Schluter Kerdi system. I installed the preformed base, membrane, and drain system.

jayp

Either you used too much water in your grout mixture or you got it too wet when you cleaned the grout out of your tiles. Did you seal it before you got it wet? Some stone is really porous. I usually put a coat of sealer on stone before I grout. It helps keep the hazing down and makes cleanup easier.

I just saw this awesome grouting method on This Old House last weekend that I haven't tried yet. You apply the grout with a float, then sprinkle dry grout and sawdust on top. Then you take a rag and sweep the grout sand/sawdust mixture up. The sawdust absorbs a lot of the moisture and the dry grout acts as an abrasive cleaner. The tiles come nearly clean when you sweep the mixture up. It was unbelievable actually. I really want to try it. Plus, it means you don't have to add any more moisture to the tiles while the grout is setting up.

Check it out -- I'm sure it's on their website. It was part of the NYC special they're running right now.

Ron6519

Where did the water come from? Was it from cleaning off the grout?
Ron

Solrac22

After I grouted I waited about 4 days and then sealed it. We started using the shower and after about a week we noticed the stones seemd to have risen above the drain. Somehow it got under the stone, couldn't tell where it originated from, stones or drain area. Around the drain was the worst but that would make since anyway given a pitch.

Solrac22

JayP, I was going to seal stones first but I was told the grout may not adhere well to the stones if the sides got sealer on them. With a non-uniform shape it would be nearly impossible for me to seal only the area not being grouted. Have you had any problems with adhesion?

Ron6519

Did you follow the Schulter directions to the ,"T"? What sort of thinset did you use? Did you set the drain into thinset? Not the collar, but the plastic insert?
I did a Schulter system for a customer and found if I didn't set the drain insert into thinset, it would push down when you stood on it. Since this is a weekend house 130 miles from home, I stay here during the week to work. I've been using this shower for a few months and haven't experienced any issue with the tile around the drain.
Ron