Polyiso between sheetrock and studs
I am in the process of remodeling the inside of my house. I’m doing one room at a time since I have to live in it with my family. The existing walls are 2X6, 24″ OC with unfaced fiberglass insulation in the wall cavities. Plastic sheeting between the studs and the inside of the drywall acts as a vapor barrier. Can I replace the plastic sheet vapor barrier with foil faced polyisocyanurate, situating it between the studs and drywall on both the exterior walls and the ceiling? I have been told no, but all the reasons given do not make sense to me, given I am replacing one vapor barrier with another. Will the increased insulation of the polyiso promote condensation in the wall cavities? Thanks.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part