Hey All, 

My home has cathedral ceiling/roof, insulated with fiberboard – no air gap. It has architectural shingle on tar paper, on OSB, on top of old tar/gravel, on top of this ~6 inch fiber panel.  At some point a flat ceiling was added in roughly 1/4 of the house in order to route pipes, wires, and an AC system. At that same time they open up vents in the soffits and added a whirlybird. 

I have been reading about unvented/conditioned attics and their benefits.  My attic already has the exact same insulation as the rest of the house, so spray foaming/additional insulation doesn’t seem necessary?  Is it reasonable to seal the soffits and the whirlybird vent, seal THOSE with foam, and then add a small amount of AC to the space?  My home is in Central Louisiana. 

Please let me know if you would like any additional information, and Thank You!