I want to increase insulation in my cathedral ceiling.

It currently has paper-faced 6″ fiberglass between 2×8 rafters with continuous soffit venting strips and gable-end vents. I have to replace shingles soon and would think solid iso foam sheets of R-20.

This should be a common problem of houses built in the 70’s. Are there pieces you wrote that address it already?

Thanks

Don Hegeman
Chatham, NY