[Neighbors] Flat roof, going from tar-and-gravel to spray foam?

[Ben Garland]

Does anyone have any experience converting a flat roof that's tar-and-gravel to spray foam?

I would like to hear about it: who you used, were they good, what did it cost per square foot, how do you like the end result, etc. I'm buying a house with a tar-and-gravel flat roof and wondering what my options are to make it last. Getting some extra insulation would be a nice bonus.

Or if you looked into a spray foam roof and didn't go that route, why not?

e.g. something like this: https://www.techwestfoam.com

Thanks!
Ben