I have laid all types of tile but never slate, I have received a great deal on some slate and am going to lay it in my Kitchen and bath. It is mutli-colored rough slate tile, 15'sq per box. Here is my questions.
What type of thin set is best with slate?
If I seal the tile with 1 coat of sealer, will I have any trouble with cleaning up after I grout. I was told that the haze left on the slate after grouting is extermely hard to clean up. What do I need to know.

You should be okay with the one coat, so long as it's a good quality sealer. As for the thinset, any of the midrange latex modified thinsets should be fine for cement board or concrete. By midrange, I'm talking about something like Custom's Versabond, Laticrete's 253, or Mapei's Ultraflex II.

Now, there's one thing you may have overlooked, if this is over woodframe-- the fact that the floor needs to be literally TWICE as rigid as it does for any other kind of flooring, including ceramic. There's a really easy way to find out of your joisting's strong enough. Get the following measurements: The width and height of the joists (2x?), the UNSUPPORTED length of the joists, and the on center spacing (from center of joist to center of joist). Once you have tose values, go to the following link and plug them in, and it'll tell you whether or not your floor will take natural stone:

http://www.johnbridge.com/vbulletin/deflecto.pl

Thanks Bill.
The floor will hold the stone, I liked that link to deflecto had to book mark that one.

Thank
Dan

Not a problem. John's a good friend, and he's got a good site. Even for myself as a pro, that "deflectometer" has got to be one of the handiest on line tools I know of!

Also, make sure when putting down the cement board that you thinset as well as screw or nail it down. For thinset under the cement board, you can use the cheap stuff (unmodified, or dryset). The thinset underneath is only to act as a cushion to eliminate vibration between the subfloor layers. The screws or nails are what attaches it to the floor.

After setting the slate, and before you groute it in. Use a good quality stone and groute sealer on the top. You do not have to do as many coats as the directions tell you just one will suffice. This will make the haze wipe off much eaiser. Once the groute done and it dries, then seal it again according to the directions on the bottle. I do this every time I lay tile that does not have a glazed finish. And it works wonders. Also you may want to test the sealer on a smaller piece of slate just to judge what it will do to the final color of the slate. It will darken it just a bit. But you need to seal it before you use it in the kitchen and bath areas as unsealed slate or stone can stain real easy.