Steel shop question

The spray foam is better than nothing but... Nothing does work where there is a dead air space. Many homes still exist that have asbestos shingles, etc.., on exterior and plaster on interior, nothing in between. Thickness and density of those exterior sheetings make a big difference. Anything against the thin sheet steel will wick the temperature of the metal. To what level the foam transfers temp' ? I really don't know.
Forgive my old school mindset showing through here. I just don't like the foam or anything that I cant take down and put back again, or work with. As far as I know, any foam that is removed, for any reason, goes to the landfill.