Impermeable over permeable WRB
Hello, I’ve seen other posts on this topic, but I wanted to chime in with a specific instance and hopefully get some feedback.
We are designing a single family home in Philadelphia, PA with Blueskin VP100 over osb and rainscreen siding.
The siding contractor added a synthetic roofing underlayment (Topshield Securegrip) between the blueskin and the rainscreen siding.
My immediate reaction is that this will cause condensation and moisture to collect within the wall which is obviously counter to the purpose of using a vapor permeable weather resistive barrier.
Curious if anyone has any experience with this situation and if there are any remedies short of removing the non-permeable layer and reinstalling the siding (such as adding vents, etc)?
Thanks in advance for any feedback.
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