Roxul Comfortboard – disadvantages?
I’m intending on insulating my 1950’s Cape style house with exterior insulation. I’ve been planning on following the CCHRC’s REMOTE wall assembly with an air tight membrane over the sheathing and 6″ of EPS foam (2, 3″ layers) then furring strips and siding.
My concern with this approach has always been limiting the drying potential outwards and having an existing foil vapor barrier in some parts of the house and poly in another part of the house. To remain living in the house, I’d like all the work to be done from the outside. Worried about creating a double vapor barrier, I’ve accepted the idea of using a vapor open insulation on the outside of the house and I could simply substitute the 3″ layers of EPS with 3″ layers of Roxul Comfortboard IS. I like this because it doesn’t change many of the details I have planned, and Roxul doesn’t burn or shrink and its a safer bet for potential moisture risks to allow drying to the outside.
The only disadvantage I can see is that the Roxul could be susceptible to some wind washing. Where the seams of the EPS or other foam board can be spray foamed or taped together, Roxul would just be butted together. If the membrane over the sheathing is the dedicated air barrier, this wind washing probably isn’t so bad, but I’m curious what others see as disadvantages of using Roxul in the place of foam board for exterior insulation?
Located in Nova Scotia, Canada – Climate Zone 6.
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