u/shazznasty

title. barn is probably 30 years old, and thinking about insulating it to try to help during times of extreme heat/cold.

i'm aware infiltration will have a significant affect, and am working on that separately.

I'm thinking of installing 2" foil faced polyiso inside the barn, fastening either directly to the plywood or to the studs. assuming i can make that work logistically, is there any issue i'm missing? is it better to have an air gap? is an air barrier a must-have? anything else?