Roxul Comfortboard to create cathedral ceiling baffle?
Hi all — thanks for taking the time to read this.
I’ll be building a new home this spring in zone 6 (northern Vermont) that will have cathedral ceilings. I’ve read a lot about the best way to do this in my climate (thanks for all the info on this site, Martin) and I’ve settled on what seems like a safe bet: taped drywall and vapor retarder paint, dense pack cellulose (16″ or so), homemade baffle, 2″ airspace, plywood sheathing, underlayment, metal screw down roof.
From what I understand, it’s nice for the material that is between the cellulose and airspace to be somewhat permeable so any moist interior air that does get through the drywall can escape to the ventilation channel. My question: in there any reason not to use rigid mineral wool (roxul comfortboard) as the baffle (instead of foam board) since it is REALLY permeable? It’s more expensive than foam, but I’m thinking it could give more peace of mind since it’s so permeable. Anyone out there tried this or can you think of any reason it wouldn’t work?