Alright we living in central Iowa (zone 5)and we are remodeling a house and put an addition on. We’re down to the insulation for the walls, on the exterior of the house it’s a mix, on the north it’s a 2 x 6 wall cavity with vinyl siding,house wrap and sheathing. On the southe side it’s 2×4 wall cavity with house wrap green fan fold insulation I believe is what they called it and what my contractor calls manure board? So the decision was to use r15 on 2×4 and r21 on 2×6 walls all Kraft faced. He also said he puts poly up as extra barrier for moisture. Needed thoughts on this second barrier. Is it needed or not and reason why. Thanks!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part