Air Barrier and Chimney Cricket for Unvented Cathedral Ceiling
We are doing post hurricane repairs and as many upgrades that fit into time and budget currently in sw louisiana. One of our roof sections has a 6′ chimney with no cricket/saddle at the bottom of an unvented cathedral ceiling (4/12 pitch). Needless to say with just soffit vents and 60s fiberglass batts it’s in bad shape from age coupled with the storm damage. A lot has been learned since 1969 when originally built as is currently.
Being in a predominantly cooling climate, and we rarely run heat even on the coldest days, would my most critical air barrier be on my exterior insulation, roof and wall layer?
The other twist is the cricket/saddle construction for the chimney. I was planning on insulating, peel and stick underlayment and air sealing above the roof deck and building the cricket above that. Would it be safer and more robust if those items also included the cricket? It would be easier in some aspects but more fussy in others.
Thank you in advance for any opinions or advice.
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I can't edit or add to my original question but I should clarify a detail or two. The original roof in question has soffit vents and no ridge vents with 2x6 rafters filled with fiberglass batts. No vent space and the vents are only in 4 rafter bays.
The new proposed build will be built up original rafters (bonfig or similar idea) filled with r30 rockwool. The outer insulation will be two 1/2" layers of polyiso staggers and taped. Unvented assembly once revised.