Galvanized Roof Rust

Unfortunately over time this coating can fail leading to minor rust outbreaks.

Galvanized roof rust.

Rust is the reaction of oxygen moisture and metal that results in reddish brown blotches. The roofs i have done have lasted a minimum of 20 years now. But galvanized metal which exhibits a shiny adherent but rust colored stain is not truly rusting. The fiber acts a bit like a tire plug in the old nail holes and prevents leaks and it sticks well.

If you are preparing to paint a rusted galvanized metal roof pay special attention to surface preparation or you will have a recurrence of rust and or flaking. Most metal roofing is made of galvanized metal or coated to prevent rust from occurring but standing water and the heat generated by direct sunlight can wear the roof s protection away. If the item is exposed to continually wet conditions the zinc develops a film known as white rust. I have used both regular paint and roof coat on old metal roofing with pretty good results.

Galvanized metal is coated with a layer of zinc to protect the iron or steel underneath. I like the fiber in the aluminized roof coat as well as in the black nearly tar roof coat. It is not simply a cosmetic problem however. Rust corrodes metal and if left untreated it can cause.