OSB exterior wall, best air and WRB
bonai
| Posted in General Questions on
Hi there,
Almost time to wrap the house. What is best:
What I want:
– use Siga Wiglub to tape all the seams of the OSB sheathing and finally wrap with Tyvek
What the contractor suggest:
– use blueskin VP100 self adhering membrane, no seams taping
cheers
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Replies
Did your contractor give you a price difference?
not yet. Price is a concern for sure but I also want to know how good the blueskin membrane is.
VP100 is solid. It takes the faintest possibility of cheap, leaky-OSB out of the equation. I'd be a little surprised if it's cheaper than the Siga tape but it's possible because the VP100 serves double duty as WRB in addition to air barrier. Taped OSB still needs a housewrap.
This may be worth a read: https://www.greenbuildingadvisor.com/article/is-osb-airtight
good read, thanks
Sounds like your siding is off. WRB answer depends on budget and the desired wall assembly. There are simple wraps, drainable wraps, self adhered wraps, etc. I priced most all of them a year ago.
What's the plan with the full wall assembly? Do you intend to provide an air gap between the siding and the WRB? If yes, I was looking at Hydrogap SA, but it was not yet available. We went with VP100 and plywood slats / CoreVent for the air gap. VP100 came in at about .60 a square foot. High perm of 33. Four times the cost of cheapest tacked-up Tyvek/Typar. 1/2 the cost of the Siga SA product. VP100 hit the right cost, air seal, perm balance for my reno.
Yes, we will have a rain screen.
walls will be:
2x4 16 oc
OSB sheathing
OSB seams taped + Tyvek or only Blueskin
1 1/2" Warmboard 80
3/4'" strapping
Fiber cement siding
I read a little more about this product, starting to like it.
Did you prime your sheathings? The installation guide says no need but I am still worried about adhesion on the rough side of the OSB.
We put the VP100 directly over the old board sheathing w/o primer (the house was an air leak nightmare).
Make sure they roll the VP100 ... I had ongoing battles with that.
Thanks!