Retrofit air barrier / WRB: Peel-and-stick vs. Solitex Mento 1000
I am in the process of renovating a 100-year old home in Manhattan, KS (climate zone 4/mixed humid). We are adding to the sheathing a WRB/Air Barrier membrane, 2″ of reclaimed polyiso foam, a 3/4″ rainscreen gap, and beveled Boral TruExterior siding.
I was planning on using a peel-and-stick roofing underlayment (a la PERSIST/REMOTE), but my contractor has expressed deep concerns about this approach curtailing drying in the wall assembly in our humid summers. He wants a vapor-open housewrap instead. It seems somewhat silly to me, as the polyiso is foil-faced and will be a nearly impermeable barrier, and the interior air will be conditioned promoting drying to the inside.
But the cost of using Solitex Mento 1000 vs. the peel-and-stick is almost a wash, after accounting for shipping and tape costs, so I would be willing to go either way. Are there any concerns about releasing water vapor under a layer of polyiso? Are any additional details required?
Thanks,
Nathan Bean
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Replies
Nathan,
Your analysis is correct. In Zone 4, you won't get into any moisture trouble if you install a vapor-impermeable layer on the interior side of 2 inches of polyiso. And, as you point out, if you are using foil-faced polyiso, you already have a vapor barrier at this location, with or without the peel-and-stick.
HI Nathan,
Curious what did you use at the end? How do you feel about it so far?
Thank you