Which Thinset to use under slate.

[donmei]

I have to install slate tile in my new kitchen, but first I'll give you the layout.

Its new construction with 2 - 3/4 sheets of t&g subfloor screwed and glued. The slate is a "random" patern with anything from 6x6 to 16x24 inch pieces.

I've been doing some research both locally and on the internet.

Right now my thought is to use Laticrete products. I'm torn between the 254 or 317 mixture. They are both recommended on Laticretes web site for this kind of install. I plan to add the 333 flex additive to either choice.

Which one do you recomend??

Also, the 253 is MUCH cheaper. Its inferior, right?? Just thought I'd ask.

Finally, I was thinking of putting down a layer of Blue 92 anticrack membrane. Is this overkill??

Thanks for all of your help.

Best regards,

Don Mei
Essex, CT

p.s. Oh yeah, one other thing. There is wirsbo "staple up" radiant system under the subfloor. I am hesitant to use Ditra because it breaks up the thermal coupling of the tile to the subfloor.

[Davy]

Don, sounds like you are planning on tiling right to the plywood, something I wouldn't do. The Ditra sounds like the best way to go although your floor needs to be strong enough. Fill in the information in the "deflecto" calculator above and see.