Advice on open cell in exterior walls, zone 5
We are going to be constructing a new home later this year and the topic of insulation has come up. I have done quite a bit of research and reading, including many articles here, and unfortunately still not sure which way to go. We will have 2×6 studded exterior walls (2 ft on center studs), with 1/2 inch sheating, Tyvek home wrap, and vinyl siding on the exterior face, and drywall on the interior face of the walls. I know this is pretty standard, and I think we’ve narrowed down the project to use either entire open cell foam in the 2×6 walls, or go with a hybrid option which is 1.5 inches of closed cell with 4 inches of cellulose. Originally I liked the idea of the open cell foam more as I have read a lot of good feedback about it, however one of the local insulation companies I have talked to says they do NOT install open cell in our area and prefer the hybrid option. They are telling me that open cell absorbs too much moisture and they prefer the closed cell option to act as a moisture barrier. I have read that it is good to let the walls “breathe”, and have also seen reports of the closed cell and cellulose hybrid option causing condensation inside the walls. I posed this question to this company and they claim that with 1.5 inches of closed cell foam that this problem does not happen in our climate.
So…. my question is, for our climate in zone 5, is open cell a good option or should it be avoided, considering the building materials being used here? I am hoping for some good advice which will help us make a better decision. Thank you very much!!
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