I’ve gotten a hold of several old slate blackboards that I intend to cut up into 1′ x 2′ tiles for my kitchen floor. I was wondering if anyone had any insights or warnings about such an installation.

I’ve set ceramic tile before, but never stone, and certainly nothing so porous as natural slate.

I want to lay it cleft-side up, so that means I’ll be setting a ground-smooth surface into the thinset–will this require any special considerations? Since each tile will vary in thickness, I was thinking I might butter each tile individually with thinset to be better able to adjust the heights a bit.

I’ll most likely use a grout bag, and probably have a toothbrush and cup of water on hand to clean up the grout as I go (I’m meticulous like that).

Should I seal the stone first? Should I attempt to use a grout release?

Thanks.