My name is dominick i am a spray foam sprayer in new england. and reading through these post i see one thing that is not coming up. Yes 2lb foam is a better insulation compared to open cell and fiberglass. I dont believe that it should be sprayed in any roof line. since it is a moisture barrier and hold up to 40 psi of water. you will never know if your roof is leaking or where it is leaking from. my company does not like spraying closed cell in a roof for this reason. you would have to replace your whole roof just for one leak. that is my only concern about any product that i spray and icyenine product does not give you the right r value that you need when applied. the best for closed cell is heatlock soy bean and for open cell is agerbalance which has a better r value that super seal 500