It is a carbon steel sheet coated with zinc produced through continuous hot dip process. This can be used either bare or painted.Metal roofing sheets have a considerably long lifespan and, although manufacturers will often state an expected lifespan of 10 – 15 years, people more than often find that they last much, much, longer with some people reporting their sheets to still be in good working order after 60 years!Metal roofs are naturally heat-resistant as the alloys used in construction are actually poor conductors of heat. That said, galvanized steel roofs take this heat resistance up a notch as they are more reflective than other metals due to the extra zinc coating