granite 24" in shower 10' high ,will it stay ?

[darvin kuehl]

I have just finnished installing the kerdi on the shower walls, ( first timer), and am now ready to start the 10' high walls. My granite was purchased from the local tile store, it is chinese 24" black granite. The store sold me a couple of bags of Pro-bond dry mix , a Superior company product, that they said I would need for these big 1/2" x 24" slabs. Is this what I should use, or should I just get unmodified thin set, like I got from lowes, that I used under the kerdi ?
We also want to butt the slabs without grout spacing. How will this work? We are using Schulter expansion strips in all inside and outside corrners inside the shower as well as on the floor. Iam sure the floor job ( outside the shower) will be a snap once I finnish hoisting the big slabs up 10' !! I bought a pair od suction cups, but , not sure if they will help? Much Thanks to anyone experenced with 24' granite work on walls. .................DK

[sgrandjean]

Darvin,
While I have no experience with granite on shower walls, I can tell you that you'll be much better off with a small grout space (say 1/16") than you will be if you butted the tiles right next to one another. Even though there's technically no space for grout the way you're talking, you won't believe the space you're creating for all sorts of stuff to find it's way between the granite pieces.
Cheers.

[Davestone]

Most grainites are bevelled for a grout joint,but i like to use small plastic shims, or plastic toothpicks to keep them aligned.I'm not familiar with probond, but any premium thinset will hold your granite on the walls,just be sure to get 90% contact.Careful with cheap suction cups..they can get you a headache.

[darvin kuehl]

Thanks for the reply Dave. I like the idea of "plastic toothpicks". My question about using the modified thin set is because Schulter does not recomend it, however , it would seem to me that a modified mortor would be adhear better to the walls.? I was told that tilemate with flexalastic is the best, however that seems to go against Schulter's statement. What gives? does anyone know ?

[jadnashua]

Schluter has a quality unmodified thinset branded under their name for this situation. John Bridge tends to use Versabond, a lightly modified thinset. Even an inexpensive thinset is still in the order of hundreds of pounds per square in in shear. On a wall, you might want to consider using the 'spot' method. This has you putting golf ball size dollops of thinset on the back of the tile, and then smushing it onto the wall. As opposed to a floor, a wall doesn't absolutely need 100% coverage, and this method will make it easier to get those large tile aligned with no lippage.

A modified thinset on the wall under those huge tiles will take a very long time to set up properly - maybe in the order of weeks. An unmodified thinset will be set overnight. Thinsets are rated for strength after curing for 28-days, and will continue to gain strength after that. The concrete in the Hoover dam is still curing, as can be noted by the heat it is still giving off - that's somewhere around what, 80-years?