I have a large structure that is well insulated (50x80 with 18ft ceiling) and I am building a 14x30 office inside of it, with 8ft ceiling. The main building will be conditioned at 55-60 during winter and 80-85 during summer. The office will be conditioned to 72 degrees year round.
My question is about vapor barrier on the office. I am insulating the office walls to R19 and filling the 2x10 ceiling joists with blown cellulose or fiberglass batts. Should I use a vapor barrier on the office and if so, to the inside or the outside?