Slate Instal - Trekkor?
 

I'm installing 12x12 slate tile in my back hallway. I have pulled up the old 12x12 ceramic from the plywood (not easy) and the subfloor is clean enough to use 'as is' (I think). There is almost no mortar left on the plywood and the bit that is there can be chiselled off.

The hallway is only about 30" wide in this area, it is very solid (plywood screwed onto sub-floor) and, since the old tile did not crack, I think it is solid enough.

So, while I initially planned to pull up the plywood and put down hardi-board, I'm now proposing to lay the slate on the existing plywood.

1. Is this a bad idea

2. What mortar should I use, just a regular Home depot thinset?

3. For 12x12 slate should I use a 1/4" gap, or 3/8"?

(Yes, I have read this thread: http://forums.pelicanparts.com/off-topic-discussions/322462-installing-slate-floor-tile.html)

You are aware that it's probably going to flake, right? I'd think that it's not a great choice for high traffic areas, like a hall.

http://www.doityourself.com/stry/layaslatefloor

from another site

Q. Can I install my slate tiles on wood?

A. The only wood surface that is recommended for the installation of tiles is exterior grade plywood.

Q. Which type of mortar should I use to install slate on exterior grade plywood?

A. Use a mortar that complies with the ANSI A118.4 (latex or acrylic modified mortar).


Q. How wide should my grout joints be?

A. It's a matter of personal taste, but traditionally slate tile has been installed with wide grout joints. We suggest 3/8" for the 12"x12" and 1/2" for the 16"x16". Due to slight variations in tile size use of tile spacers is not recommended with slate tile.

I think my wife is more concerned about the appearance than the practicality. But, yes, just like my pool deck, I expect flaking.

It is exterior grade plywood. Plus it is slightly roughed up from the ceramic removal. I don't think there will be an adhesion problem.

I'll see what Home Depot has for mortar tonight, no doubt their 'associates' are up-to-date on ANSI specs.

I will try 3/8" gaps on my dry-fit and see if they meet the 'Project Managers' approval.

I generally use the Versabond stuff when putting tile down. There's also a Versabond product for Granite and Marble, but I think that would be unnecessary for slate. Besides, I think it's white and for slate gray would probably be better.

I did a bit of checking on the net to see if the Versabond meets 118.4. This is what I found.

# *Exceeds ANSI 118.4 if mixed with Admix