Do Roof Shingles Insulate?

Submitted By
Tom Kraeutler
1 expert, 0 community

I have a question about roof replacement and whether or not roof shingles insulate. My composition shingle roof was installed in 1984 and is starting to curl at the edges. Should I remove the shingles or would it be okay to apply a new layer on top of them? Leaving the old one on seems to provide an insulation in my mind, but I would like your opinion.