Be careful with an impermeable vapor barrier especially if adding one. It may work perfectly for keeping water out of the wall cavity in winter, but become the condensation layer in summer - on the wall side!
You can use smart vapor control layers (such as Intello) to counteract this - but be sure you’ve discussed how the wall can dry out if it gets wet.
And the worst of all is if you end up with two vapor barriers - one on the inside and one on the outside - you’ll end up with a “dirty diaper” effect.
You can use smart vapor control layers (such as Intello) to counteract this - but be sure you’ve discussed how the wall can dry out if it gets wet.
And the worst of all is if you end up with two vapor barriers - one on the inside and one on the outside - you’ll end up with a “dirty diaper” effect.
https://www.buildingscience.com/documents/digests/bsd-106-un...