Rockwool on roof sheathing
For a roof with exterior insulation on top of the sheathing, is it possible to use rockwool instead of rigid foam?
I was reading here about how mineral wool, as an an air permeable insulation, was not a good choice for inside of stem walls, as air can still contact the cold stem wall surface and condense. Would the same apply to roofs, avoid air permeable insulation on top of the deck, because condensation will still happen?
This is for a compact roof assembly in CZ3-coastal, zip 95060. Roof detail is attached.
Roxul sells products for roofs: http://www.roxul.com/products/roofs/, but based on what I read about condensing in the crawl space, I’m skeptical.
Links I am referencing:
GBA Detail Library
A collection of one thousand construction details organized by climate and house part