Unvented vaulted ceiling insulation
I’ve read a lot about vented/unvented “cathedral” type ceilings on Green Building Adviser. Now I’m trying to really sift through the grey-area of conflicting information from all sides (my landlord, contractors, the internet, etc.!).
I have 1600 sq/ft barn just outside of Seattle with vaulted ceilings and a loft that runs through the middle (see pictures attached). The original plan was to spray foam the whole ceiling in between the jopists. However, the landlords became skeptical of this method – citing health and environmental hazards. This seemed to be a good plan because as you can see, the joists run the wrong way to easily vent the ceiling. And, I’m trying to retain the ceiling vault and height because the building is now intended to be a recording studio. I intend on using the whole building including the loft. I started reading that cut-and-cobbling between the joists with 2 inches of R-5 an inch XPS rigid foam insulation and sealing the edges *could* be a suitable vapor and climate barrier *without* venting the ceiling.
Curious what you think of cut and cobbling in my situation, spray foam, and any possible alternatives we might consider.
And for reference, I have read both:
Thanks so much,
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