Flooring Tile - Unmodified thinset over a slab?

Hi,

What do you guys think of using UNmodified thinset over a bare concrete slab that has no cracks and has been there for 15 years? I figure one gets more adhesion without the latex, and saves some $$ as well. This is for a sunroom floor with 12x12 lazed porcelain tiles.

:-)

Leo.

You will get much better adhesion with a modified thinset than with an unmodified. Unless you were using Ditra as an underlayment then modified thinset, combed onto the slab and a skim coat back buttered on each tile will work out well. Don't let any grout around the perimeter of the room either. Leave an empty 1/4" all around. Cover with base or fill with color/texture matched caulk.

By the way, please keep one thread for the whole project so duplicate questions about the project don't interfere with getting a quick response. I was going to ask if the slab was sealed or painted and decided to check you other posts through your profile. Pick one thread, this or your slab hump thread and just keep asking all your questions there without starting any more threads on this subject. Makes it easier for us to follow along without regressing. Adding a question to a prior thread will bring it back to the top of the page.