If you live near the coastline, a saltwater environment, or any brackish (salt and freshwater mixed together) water, there are some considerations you need to make when purchasing your metal roof.
It is widely recommended that all metal roofs within these kinds of environments use an aluminum roof system. Aluminum, versus the typical galvalume aka steel metal roofing material, is resistant to corrosion and rusting from saltwater. If a homeowner near the coastline were to choose galvalume/steel roofing materials for their roof, their galvalume warranty would then be voided.
Your 1st Coast Metal Roofing Supply sales representative will be more than happy to provide more information on these warranty exclusions and helping you choose the right material for your home location.