Can you use Great Stuff foam as insulation under a metal roof?

Question

Have a patio with metal roof, gets very hot during summer. Will Great Stuff insulate and stick to hot roof during summer? Thanks

Answer 1

Great Stuff (and similar products) stick to just about anything...and with vengeance. If you haven't used it ever, DO NOT let it get on anything else: it is the nastiest.

To your Q; It's possible to cut this stuff after it dries up, but still would look like crap.

Get some sheets of 'blue board' (an extruded polystyrene) and cut it to fit around structural members. Cuts with a hand saw, knife, and is easy to work.

There's a glue for it but I haven't used it on all surfaces.

It would look far better than Great Stuff alone.

Answer 2

I installed a metal roof 5 years ago. I stripped the roof down to the plywood and put down 30# felt. This was what the manufacturer recommended. The felt is not for insulation though. The company was Metal Sales out of PA. They are glad to give advise.

Answer 3

Probably could, but it would look like crap. Painting the roof white would do a better job of keeping the metal cooler. I'd install a ceiling fan in the center of the roof instead to force the hot air out.

Answer 4

I don't think Great Stuff foam insulation is meant to be applied in the manner in which you need. It is used to fill gaps and cracks, not be sprayed out in thin coats. whenever I've used it in the past, I found out it did not like to be spread out, or "worked".