HELP! Am I Making a Fireproof Mold Sandwich?
I am an architectural designer working with my Principal on designing a new single-family home in the NY Finger lakes (Climate Zone 6A). The house is supposed to be low-maintenance, low-embodied carbon, and fire resistant.
Our current proposed wall section is as follows, from EXT to INT:
I have done an assembly very similar to this on other projects with great success at other firms. My Principal is (perhaps rightly so) concerned about the growing risk of forest fires farther east, and for that reason wants to propose the following assembly, citing improved fireproofing and better control layer management:
LIQUID APPLIED WRB OR WATERPROOF MEMBRANE
My concerns are:
>this assembly does not let the exterior insulation dry
>there are alot of heavy layers outside of the studwall, creating a moment force issue on the fasteners
>I am skeptical that the TimberBoard has to be fire protected – I would rather use VulcanVents or just CorAVent at the top/bottom of the rainscreen (from this BSC article it seems a smaller rainscreen gap could be just fine) https://buildingscience.com/documents/building-science-insights-newsletters/bsi-098-great-fire-london
>concerned that adding a “sealed” control layer outboard of the exterior insulation will trap any moisture that gets into it, preventing it from drying properly with the rainscreen gap
>making the Intello the primary air barrier with no service cavity will let lots of interior moisture into the assembly if holes are poked from hanging pictures, etc.
Help! Am I making a mold sandwich? Which assembly is better? Any recommendations? ComfortBoard not preferable due to embodied carbon concerns.
Thanks! – JHWEHRLI
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