Interior insulation of unventilated roof – GreenBuildingAdvisor

Hi All,

Currently have an unvented roof in zone 6 Vermont with fiberglass insulation.  I want to put a new roof on but not before fixing insulation issues.

I am thinking closed cell foam on the exterior (R 30+) then the new standing seam roof.

Do I need to worry about the possibility that the fiberglass has likely settled under the roof deck creating an air gap?

If this is a condensation concern can I solve it by going above the required R value of the exterior foam or do I need to blow in cellulose from the inside?

Thanks!