When the subject of insulated rooflines rather than vented attics comes up, one concern is the house’s shingles. Roofing companies claim that shingle lifetime is reduced drastically when the shingles are unable to conduct heat from the sun downwards. The Florida Solar Energy Center (FSEC) addressed this subject in a review on the need for attic ventilation a few years ago. As part of the review, the FSEC measured shingle temperature on houses that had insulation at the flat ceiling with a vented attic and compared that to shingle temperatures on houses with insulation at the roofline. They found temperatures differences were slight and no danger to the lifetime of the shingles.
Read the full article here: Insulated Rooflines and Shingle Temperatures