Foam Insulation Option with Internal Poly Vapor Barrier?
My existing home has 2×4 exterior walls with a polyethylene sheet installed in front of the studs and behind the drywall. The walls are insulated with faced batt insulation The exterior sheathing is brown fiberboard. House was built in 1977.
I searched this site, but can’t find any acceptable recommendations for insulating with exterior foam panels. I’ve read all the articles about the bad things that can happen when moisture is sealed between an internal and external barrier?
Are there any options to add external insulation? Am I just out if luck?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part