Grout with admix or siliconized caulking? [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


View Full Version : Grout with admix or siliconized caulking?

john h
02-25-2008, 11:16 AM
Hey folks...

Love the site, learning tons - Thanks!! I'd call myself a fairly noob hobby tilesetter, but I've read and studied tons of stuff.

Anyway, I'm embarking on my first kerdi tub surround. I live in SF and of course buildings move here. I do intend to make the corners of my framing rigid. I am wondering in i can use modified grout or grout with admix for all joints, including the wall-to-tub joint, in order to provide flexibility when the building shakes and hopefully minimize cracking. I really dont want any caulking around the tub, mildew grows readily here.

I read John B's Kerdi Handbook and he states he uses grout in all his corners (errr... dont think he mentioned whether modified or not). I think he was talking primarily about stall showers, not tub surrounds though. Hope i didn't misunderstand him or misquote him.

Next question - admix will make the grout more impervious to moisture, yes? so if cracks do develop, the moisture will have a tougher time evaporating, right?

Also, if i did use siliconized caulking around the tub and the grout above let in some moisture, is it possible for the moisture/water to work all the way down to the caulking and pool behind the caulking and not evaporate efficiently?

I'm half way tempted to suggest unmodified grout in a well-constructed shower is ok? even if cracks do develop and water/moisture gets in, I'm protected by the kerdi and the unmodified grout will let it evaporate eventually, right?

Thanks in advance for the advice, folks!!

Sponsored Links

John Bridge
02-25-2008, 04:58 PM
Hi John,

You'll have to use caulking between the tub and the tile. No way will any kind of grout stay in there. As to modified v. unmodified, I don't think you'll have a choice. All the stock grouts I buy these days are modified. :)

john h
02-26-2008, 11:05 AM
Mr. Bridge,

Thanks for the reply sir, an honor to receive a reply from you! :bow: Down the road I'll probably meet a set of walls that are begging to be mudded, so I'll pepper you all with more questions then!