Self Adhesive WRB: What’s the ideal PERM RATING in Maine, Zone 6A
Looking at various products, while on a budget (who isn’t these days?!). I’m trying to stick to about .80¢/square foot, so products like Blueskin VP100 (33 perms) and Grip-rite ProWrap SA (66 perms) stand out. But so do their higher perm ratings. I’ve seen articles saying 10-20 is ideal, but products like Hydrogap SA and SIGA Majvest SA are so pricey. But I also understand the importance of a superior product, so like everyone, I’m trying to find the balance. On the high end SIGA would cost about $1.50/sqft while low end ProWrap at about .75¢/sqft. With 1400+ sqft of area, that’s about a $1050 difference.
FWIW, I’m located on a hilltop with some decent exposure.
To help, my wall assembly is:
– 2×8 framing 24OC (https://www.greenbuildingadvisor.com/article/furred-continuous-insulation-wall-assembly-to-meet-2021-codes)
– 1/2″ CDX sheathing
– WRB
– Rain screen (like BO Slicker but possibly furring strips)
– Vertical natural wood shiplap siding
Thoughts, concerns, input much appreciated!
Thank you!
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With you being in a cold climate, and given your assembly includes a rainscreen and wood cladding, a little higher perm rated product would be better. You had mentioned the Blueskin product, which is 33 perm, ProtectoWrap's Protecto Wall VP is 43.5 perm. I wouldn't be afraid to use either one in a cold climate. If you changed your siding to a reservoir cladding like stucco or brick, or if you lived in a hot and humid climate, I would think about moving to a less permeable WRB.
Thanks for the feedback Randy. I've been waffling between Blueskin and HydroGap. With your input on the increased perm rating, and the approx $700 savings, I think I have a winner. Much appreciated!