Newer construction major sheathing rot over closed cell foam
We are seeking any kind of input on how to remedy this issue. We built our house in 2014 and have discovered major sheathing rot behind our siding. The rot is on the lake side of a home in Connecticut (western side of house). The home has boral true exterior v groove and boral true exterior trim installed over benjamin obdyke hydrogap, installed over 1/2″ CDX ply sheathing, installed over 2x6s, with closed cell spray foam between the 2x6s.
We had some rusty nails and warped trim which led us to pull some off. We discovered HUGE amounts of rot. Initially we thought that this was secondary to water intrusion along a couple of joints on the boral siding which had opened and were imperfectly caulked, however we have looked closer and the majority of the rot is nowhere near where there is water intrusion.
I suspect that water is getting in behind the siding, possibly through condensation, and then because the spray foam is closed cell any water that is trapped there stays there and rots the sheathing as the siding is tight and presumably the moisture cannot get out. When we installed the spray foam it was billed as the best insulation and came at the recommendation of our architect and builder.
Any input on how to remedy this situation would be greatly appreciated.
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