With a proper primer urethane paint can last for years.
Paint roof with urethane primer.
Apply the sherwin williams paint and primer to a galvanized roof with a paintbrush or a roller specifically designed for corrugated metal.
Though urethane paint is very durable the surface to which it is applied largely determines which primer to use.
Urethane roof coatings more commonly known as polyurethane roof coatings are among the strongest and most durable elastomeric coatings available in the industry.
For pricing and availability.
Black jack elasto kool 1000 5 gallon elastomeric reflective roof coating 10 year limited warranty item 139941.
They are most commonly used for sprayed in place polyurethane foam insulation as well as other commercial roofing substrates including modified bitumen single ply epdm smooth gravel bur and concrete roof decks.
However for specialty applications like marine or automotive there are additional considerations.
If crawling around on a metal roof in the hot sun does.