furring strips vs osb exterior of rigid foam
my builder would like to put a layer of osb on the exterior of rigid foam instead of using the typical furring strips I see. The idea was this would be easier to make flat and install windows/etc. onto which would save more on labor than the cost of the extra layer of OSB. So the assembly is drywall -> mineral wool insulated 2×4 framing -> ZIP sheathing -> 2″ polyiso -> OSB -> homeslicker rainscreen -> cedar siding. Any potential issues with this? Would all seams on both layers of OSB need to be taped as well as the foam, or only on the first ZIP sheathing layer? This seems like it may run into the same issues found with SIPs as it is effectively a site built SIP at this point, but for walls maybe not all that bad.
thanks for any help
GBA Detail Library
A collection of one thousand construction details organized by climate and house part