I am building a small temporary 16x24 house in climate zone 5A. The last house I helped work on still used polyethylene interior vapor barrier. Help me pick the best wall assembly since so much has changed.
I read through the new IRC but I want a little better than the minimum. It will be 2x4 wall with R15 cavity and two inches of continuous exterior insulation. I am just not sure what is generally considered the best options now for 5A.
My proposed wall would be:
Sheetrock w/R15 faced batts OR rockwool with smart vapor barrier > Zip sheathing > 2 inch rockwool comfort board > 1x3 rainscreen > aluminum lap siding.
In my head this would work because it could dry either direction from the zip sheathing and with the continuous insulation ratio to wall cavity, it shouldn't have any condensation issues.
But would I be better to use 2 inch foil faced polyiso with taped seams instead of the rockwool comfort board? It would offer better insulation and additional waterproofing. If doing polyiso I could move a basically zero perm layer on the outside but then I feel like there could be drying issues between the zip and foil face of the polyiso?