Spongy flat roof
We recently bought a house, in Alaska, that a commercial concrete contractor and his contractor friends built in stages as he, the cement contractor, lived in during the various stage of completion.
The roof is absolutely flat is built with 14″ BCI that are 24″ on center. He had closed cell foam sprayed under the roof deck, and added 2 layers of 5″ x 24″ fiberglass batts. There is no vapor barrier on the underside The roof sheeting is 3/4″ CDX with a hot mop tar and paper coating. Needless to say there is no drain and thee are no venting of the roof deck and it has gotten soft in a number of places.
I am contemplating sheeting over the soft deck and building a 1/12 shed roof with an EPDM cover over the existing decking, ripping out all of the ceiling drywall and re-mediating any problems that may be present. Should I insulate the new shed roof and add vapor barrier between the new drywall and old roof deck?
Thank you in advance and I look forward to your help.
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