Converting unvented cathedral ceiling to vented assembly
I have a room with a cathedral ceiling that has open cell spray cell foam insulation in the roof deck between 8x2 rafters. I consulted with a building scientist who performed a bunch of tests on my house as a whole, as well as the room in question, which has significant spray foam odors that are particularly bad during hot and humid days (Atlanta, GA). Specifically, the building science engineer concluded that aside from having a somewhat leaky house, the spray foam is the source of the odors in that room.
This raises the question of having the roof converted from a hot deck to a traditional soffit / ridge vented system. I consulted with a roofing expert and his assessment was that indeed the conversation can be done. He informed me that taking out the open cell spray foam and placing rock wool with baffles would be an appropriate conversion. His question, however, was that he may be able to get 6” at most of insulation inbetween the rafters, and that as far a R value goes, it might be worse than what I have now. That said, my main objective is to get the spray foam out of the roof because the VOC odors it emits during hot humid days is rancid and objectionable, and makes using that room impossible for the many months of the year that it’s hot here in Atlanta, GA. The contractor said that while this project is entirely possible, he cannot guarantee that the odor issue will be resolved to my subjective satisfaction, which I thought was an honest consideration.
I’d love to get some feedback on this project— perhaps the overall feasibility, the likelihood that removing the spray foam will reduce the interior odors, and perhaps any other risks or considerations to keep in mind. There seems to be little experience out there doing this conversation to specifically address odors from spray foam that is roughly 18yrs old.
Thanks to all.