Calsil Board specs Professional opinions appreciated.

[Pizzahorse]

That is the zelieblok 2000s, yes? I just bought it today for a similar price. Mine is sitting on 4 inches of perlcrete, so is anyway overkill.

The specs appear to be similar to the fb board.

[MichaelPBoisvert]

Attachment is too small and not readable.

I edited the previous post. That should be better. thanks

[UtahBeehiver]

Attachment is too small and not readable.

[MichaelPBoisvert]

I've attached the CalSil specs I'm looking at. Price: 2000°F Lightweight CalSil board 2"x24"x36" - $59 Each . I have 4" of Rebar reinforced concrete for structural. And I am thinking about doing 2 layers of the 2" CalSil. Does that seem to make sense, or is it overkill? Do I need to do anything about a waterproof layer, or am I ok with just this?