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Community and Q&A

Exterior Insulation Thickness and Vapor Permeance

andyfrog | Posted in Energy Efficiency and Durability on

Is there a good resource online to understand how the thickness of exterior insulation (or any material, for that matter) affects the vapor permeance of an assembly?

I hear things like mineral wool and wood fiberboard touted as more vapor permeable than foam, but it seems like if the insulation is thick enough, it approaches a low enough permeance that the differences are not as significant.

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  1. Expert Member


    As usual Martin explains this far better than I could:

    1. andyfrog | | #2


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