I’m having a home built in climate zone 4 (Kentucky) and my GC will soon be completing some of the final insulation details. I’ve used a lot of the information I’ve found here to guide him on the details but have one question on rim joist insulation I can’t seem to find anything on. In Climate Zone 4, is it acceptable to use open cell spray foam to insulate the rim joists? I’ve also used Zip R-6 for continuous exterior insulation which covers the rim joist and is air sealed to the foundation. I’m familiar with the cold climate requirement to use closed cell as an air barrier to prevent condensation but is this still needed in my situation? I’d like to use 5” of open cell if that is acceptable. Thanks for any info you can provide!

Jason