David L. Martel wrote:

I need to put on another layer of shingles. Asphalt and fiberglass
shingles sell for the same price. Does anyone have an opinion on which is
better for re-shingling?

Asphalt shingles are either asphalt reinforced with fiberglass or
asphalt reinforced with cellulose (organic), but I've heard of some
being made of asphalt reinforced with polyester.

The Aug. 1997 Consumer Reports found that organic shingles always did
very well in freeze-thaw tests, but a few fiberglass shingles did,
too, including GAF Royal Sovereign.

I'd much rather have fiberglass shingles because of their much better
class A fire resistance rating. There have been some residential
fires where the fire spread along class C asphalt-cellulose shingles
but stopped right where the class A fiberglass shingles started, in
one case in a Houston apartment complex. Class A isn't just a
slightly better than class C; it's a lot better.