Insulating cathedral roof in a hot humid climate
I have been reading through a bunch of the information on this site from articles to discussions, and there is a bunch of good stuff here – probably too good since I feel like I am at information overload at this point! What I would like to ask at this point is if I have everything properly understood.
With all that I have read so far, it seems like the proven practice to insulate a cathedral roof line is create eave-to-ridge vent channels by tacking in a thin wood strips, adding rigid foam, air sealing the rigid foam, then installing insulation from there. If I do not use vent channels, then closed-cell foam is the proven way to go.
We have a two-story, detached barn garage in Houston that we want to finish out to make an apartment space of about 800 sq ft. I was hoping to save a bit and DIY the insulation mostly utilizing rock wool, but with only 2×6 rafters and wanting to vault the ceilings and cover in shiplap, it seems closed-cell foam would be the best route to go, unless I want to lose space and make a bunch of additional structural work.
I am attaching pictures of our structure to help visualize, though the frame only picture is prior to us adding to the space over the porte cachere.
Any input is appreciated. Thank you!
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