
Is the original surface unpainted or was it painted?
Unfortunately I can't see your photo. I have never had personal experience with the following product but it seems to be designed for what you want to accomplish. https://www.everbritecoatings.com/metal_roofs.html
Hello I have a galvanized metal roof that has lost its luster. Its dull and chalky. I would like to restore it to its original luster by applying a clear coat but I'm having trouble finding the correct one. Which clear coat do i need for this roof? Thank you in advance.
I believe it was painted black.
Here is a side by side picture. The piece on the left is exposed to the sun and has become dull. The piece to the right gets very little to no sun.