By Larry Stevens
How-are-exterior-bolts-and-screws-sealed-against-the-elements
All exposed fasteners are zinc coated with baked on paint to match the sheeting colors. Hardened long life fasteners on the roof with one piece EPDM seals.
Do not be fooled when you see some companies offering stainless steel fasteners. These are by nature softer and have a greater tendency to snap off during installation, they also are not rust free.