Sheathing: plywood+Blueskin vs ZIP system

So the Advantech sheathing option from my previous discussion is out. Can’t get it. So that realistically leaves me with two options: plywood with Blueskin fully-adhered WRB vs. Zip system. Not interested in nailed-on tyvek housewrap.
My top priorities remains weather resistance/longevity and structural strength. Exposure sensitivity is also important because we’re building this ourselves while working full time so we may not get it fully dried in as fast as we’d like.
Opinions?
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have you considered a liquid applied wrb?
they go on with a paint roller or sprayer and some are rated for up to 12 months of exposure . a quick google says about 180 days for some of henrys products.
Polyguard UV2-40 (previously named Alumawrap) is a 40-mil thick peel-and-stick WRB rated for up to 24 months exposure. Can't beat that. Also it tested very well at the UT Durability Lab by Dave Nicastro.
that product has a 0 perm rating, wouldn't that be pretty risky to use ?
I can't think of any normal situation where a zero perm WRB would be anything but dangerously risky to install. It would be ok if all of the insulation was exterior rigid foam, in climate zones 7 or higher.
Yeah I absolutely won't do zero perm. I'm in south florida. Vapor barriers are a no-no down here.
Woah guys, I think we are throwing the baby out with the bath water here. Hot humid climates are the EXACT place where a zero perm barrier exterior of the sheathing is a great idea. Your main source of humidity is from the outside and this prevents any migration inward. As long as your wall can dry from the WRB in or from the WRB out you’re golden. Please watch this Risinger video where Kristof Irwin did some WUFI wall assembly modeling and showed it works perfectly fine in all but the coldest climates:
https://m.youtube.com/watch?v=xPXcnioVBFw
I trust the actual science here. Also, the Durability Lab results basically concluded that the number one determining factor for longevity/durability of any WRB is its thickness. At 40-mils this product is one of the thickest WRB’s available. A lot of fluid applied WRB are more like 20-mils when WET and much thinner when finally dried.
OK, I know and trust Kristof. I am heavily oriented toward heating-dominated climates and literally forget about hot/humid climates.
They are structurally equivalent. If you have help installing it and costs are equivalent, or you have a crew you don't fully trust to follow the rules, I'd lean toward plywood with Blueskin. If you're doing it alone, or you have a crew you have full faith in, the Zip system is just as good, but you need to be careful to tape the joints properly. Just because the tape sticks doesn't mean it's doing what it's supposed to.
My wife and I are the crew, and I don't totally trust them :-)
The ply+blueskin seems like it may be more foolproof other than wrangling a big sticky 4' roll but we're using a SA roof underlayment anyway (sharkskin ultra SA) so I'm thinking we may as well stick with similar systems, unless I can find a real compelling reason to go with zip.
Dave66,
I'm not sure of your whole assembly, so I'm not commenting on any aspect of that. But, I recently used Benjamin Obdyke Vapor Dry Sa, which is an acrylic adhesive WRB with a 14 perm rating. It probably compares well to blueskin, but installs really well with a two part release paper and has excelent adhesion. I really liked working with it and would use it over blue skin. Just one guys opinion for thought. Good luck!
With most peel and stick WRB, the overlap spec is the same for both vertical and horizontal install so you can do a vertical install.
This is much easier as you can peel back about say 6" of backing, stick it to the top of the wall then peel the backing and squeegee as you go down. This avoid having to deal with a long floppy sticky piece. One thing to never do is pull off the backing of a long section that is not yet adhered.
I find installing the WRB while the wall is on the ground easier. You do have to have a plan for transitions and edges so everything ends up properly shingled and lapped once complete, so a bit more planning. This avoids scaffolding or ladder work plus the wall is pretty much dried in as soon as you stand it up.