Will poking small holes in 2 inches of exterior polyisocyanurate allow my wood studs to breathe?
I have a continuous layer of 1in polyiso on the exterior of the studs, then 2×3 strapping, and another layer of 1in polyiso inbetween the strapping. The stud cavities are rock wool. I have a 6mil poly vapour barrier and then a 2in layer of XPS before strapping and drywall on the inside of the studs.
In my attempt to get a high R value, I didnt fully understand the implications of creating a vapour barrier on either side of the studs. I am now concerned about moisture being trapped in the walls and the rot and mould that goes along with it.
My siding will eventually be board and batten but I only have the boards installed so far. I was thinking that a quick and easy way to fix this is to poke small holes though both layes of polyiso by pushing 6 guage wire in between the boards right before I put the battens on.
I consulted a local home energy professional before building the house and he said the wall construction detail wasnt ideal but if the blowerdoor test reveals that the house has a 1 or less air changes per hour (@ 50kPa) it should be fine.
I live south of Ottawa Ontario (similar climate to upstate NY).
I’m open to some creative suggestions! … but realize that to solve the problem I may have to remove the polyiso and replace it with XPS.
Thanks for your time and energy
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