I am insulating the ceiling of a tuck-under garage as well as running new circuits to my garage. I’ve read this article but I have a few questions. I am in southern NH climate zone 5/6. https://www.finehomebuilding.com/2012/03/08/how-to-insulate-a-cold-floor
1. Can I use polyiso insulation here? I know the perm rating is much lower than EPS. Do I need to be worried about moisture getting trapped?
2. The rigid foam layer (if properly detailed) is the air control layer right? So I don’t need to worry about making the drywall air tight?
3. Does anyone have good examples of air sealing electrical penetrations through a rigid foam layer?