Two WRBs?
coffeecremer
| Posted in General Questions on
I’m working on a house, in Climate Zone 6. The walls are wood framed with vapor barrier (membrain) on the interior. They are sheathed with 5/8″ CDX plywood, then Blueskin VP-100 WRB, then 2″ mineral wool insulation, then 1×4 vertical wood battens, and then cladding. The cladding manufacturer suggested we consider installing a a second WRB (like Tyek) on top of the battens and behind the cladding, to protect the battens from potential rotting. Vp100 is 33 perms, and Tyvek is 54 perms, so is there any risk of trapping moisture in the mineral wool layer?
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Replies
coffeecremer,
No risk to the mineral wool layer, but some diminished drying to the backside of the cladding, which may or may not matter depending on what it is.
The battens have excellent drying potential in the cavity. We simply don't see problems with them in rain-screens barring some other issue.
Got to say it seems a bit odd the cladding manufacturer has so little faith in their product they think there will be enough bulk water intrusion to rot the wood behind.