I Googled "Durock thermal conductivity" and got some interesting hits.
It seems this is some good stuff for shielding your wood or pellet stove from walls
and floors containing wood.. Good to know. I may re-install my wood stove someday.
I was looking at a thin sheet of Durock a few weeks ago.. It was HEAVY stuff!
It felt like I was handling a sheet of solid concrete. It's some impressive material,
and I was wondering what it would do to my saw blades..