Thick polyIso as site-built vent baffle
I’ve just read the article on site built vent baffles for roofs.
I’m wondering if there is any problem using thick polyiso, say 3 inch at the vent baffle in a vented cathedral roof. In this case the foam would not be foil-faced.
I understand that an airtight ceiling is the most important part. If the rigid insulation was thick, you’d get a higher R-value and the underside would not be cold, therefore less likely to condense. Right?
This is an approach I have not seen covered here yet. It would be similar to the Cut and Cobble method but be vented.