Interior insulation for rim joist covered with rigid exterior foam
I plan to use R-20 exterior rigid foam. My foundation will be Superior Walls, with R-20 insulation. Should I add insulation to the interior of the rim joist in Zone 5? If so, what’s the best option? I understand that having rigid foam on both sides of an assembly can be problematic, and that fiberglass can be problematic in a rim joist. Would the exterior rigid foam make fiberglass or mineral wool viable? If not, what would be my best option? Open cell spray foam?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part