---In STMFC@..., <golden1014@...> wrote :
Yes, it's my understanding (because Ed has told me this a thousand times) that the seam caps were not galvanized so they would hold paint better.
First I've heard that. The whole roof would hold paint better if it weren't galvanized... but the purpose of galvanizing was to make the steel last, whether it was painted or not. If the caps were not galvanized, they'd be prone to rust out from water trapped between the caps and sheets, and rust out from behind the paint like a modern day automobile. I wonder if the caps were formed from steel sheet that was galvanized on one side only. Seems like a rather deep draw to be cold formed, though. Wish there was some SRECo. literature that explained the production of their roof system.