Micore 300 as chimney chase insulation?

[begreen]

The suggestion was to use it as a fire barrier. The pipe is already insulated and the chase will keep it warm. I would think that you don't want the chase temperature to get too high or you start having concerns of pyrolysis. FWIW, a whole lot of chases out there have no insulation at all. My suggestion is that Durock is a better product to use than drywall because it's non-combustible, with no papered sides.

 

[BurnIt13]

I was in the same situation as you when I first started my installation. My chase is built into a dormer so the roof exit is at the top of the chase. I insulated the chase using normal pink fiberglass. To prevent it from accidentally falling inward someday onto the chimney pipe I used aluminum flashing as strips on the inside of the flashing. So if the fiberglass ever detaches from the Kraft facing it will just rest against the aluminum strips of flashing.