I have a college dormitory with 4" face brick, R7.5 ci, 6" metal stud on 16" centers, r19 closed cell spray foam and 5/8" gypsum. Per 90.1 Table A3.3 my u-value would be 0.06. This seems high and is almost identical to the baseline U-value. I would think the R7.5 ci plus the R19 foam would perform better than the R7.1 used for the cavity. Does anyone have any experience with this wall type? Would an alternate calculation be accepted? Thanks
