Hi all, 

I recently scored about 80 sheets of 4’x8′ 1.5″ polyiso headed to the dumpster. I’d like to add it as exterior insulation to my barn. The barn is in Rhode Island, zone 5. 

My wall assembly would be: 2×4 insulated stud wall, sheathing, 1.5″ polyiso, WRB, vertical furring (drainage plane), horizontal lap siding. 

My question: the insulation is paper faced. Would you have any concern about a paper-faced product and mold being within this wall assembly?

Thanks a bunch, 
Dave