Exterior foil-faced polyiso question
I live in the San Francisco Bay Area and my application is as follows:
Plywood – sealing all plywood seams with Signa Wigluv – 2 layers of ¾” foil faced polyiso (all seams taped) – WRB – Rainscreen – Fiber cement siding:
The plywood is serving as my primary air barrier. I understand that any moisture that gets behind the first layer of polyiso (between the ployiso and plywood ) will dry to the inside and any moisture that gets on the outer layer of polyiso will dry to the outside.
My question relates to the area between the two layers of foil faced polyiso.
If water gets between the two layers of foil faced polyiso, the only escape route would be gravity – i.e. to drain to the bottom of the wall assembly. So that would mean that I should not put any adhesive / tape that could block the water between the two layers. Am I thinking correctly here – or do most people put adhesive / tape between the two layers of the foil faced polyiso?
Thanks for any comments?
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