Galvanized Roof Rust

Rust is the reaction of oxygen moisture and metal that results in reddish brown blotches.

Galvanized roof rust.

Unfortunately over time this coating can fail leading to minor rust outbreaks. I like the fiber in the aluminized roof coat as well as in the black nearly tar roof coat. The fiber acts a bit like a tire plug in the old nail holes and prevents leaks and it sticks well. It is not simply a cosmetic problem however.

Rather this is just a phenomenon that often occurs in galvanized materials due to intermetallic alloying of iron and zinc i understand and is not indicative of the end of the useful life of the galvanizing. The roofs i have done have lasted a minimum of 20 years now. If the item is exposed to continually wet conditions the zinc develops a film known as white rust. Galvanized metal is coated with a layer of zinc to protect the iron or steel underneath.

Rust corrodes metal and if left untreated it can cause. 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. Galvanized metal roofs are coated with a layer of zinc that inhibits rust. I have used both regular paint and roof coat on old metal roofing with pretty good results.