A caller asked about coating 3000 sq ft of barn roofing with copper liquid coating. He wanted to save some money by coating the metal roof first with an aluminum paint, then top coat with copper liquid. The penny saving approach might be problematic.
One of the most common complaints about roof paint is flaking. If the aluminum paint cannot move with the metal, then any top coating of copper liquid would flake. The reason is coatings can only bond to what is under it.
If you are coating a roof yourself, be sure the paints move with the metal.
