Is fiberboard air impermeable?
A recent GBA post noted that some builders are finding that OSB isn’t always air impermeable. I’d like to know if fiberboard, such as Biltrite or BraceRite, is air impermeable. Specifically, I’m interested in trying to use it as an air barrier, in an assembly where I need the sheathing to be able to dry, and fiberboard has a permeability of around 20. But can it be an air barrier, if I tape or otherwise seal the seams? I can’t find this info on the company’s website or anywhere else I’ve been looking.
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