A metal roof is a cheap and easily installed covering for buildings of all sizes. Sheet metal roofing panels can be found on homes, warehouses, storage units, detached garages, and much more. For all its benefits, however, metal roofs do have some drawbacks. They are highly susceptible to oxidation or rust buildup. A metal roof is strong enough to withstand the elements for years, but does not always keep its pristine shine. Chances are a roof out in the open will develop rust and oxidation. If you are trying to paint or restore a metal roof covered in rust, you need to know about a few common methods of dealing with those ugly areas.
Sandblasting is the most well-known and effective method of removing rust, paint, or other imperfections from a metal surface. You may have seen it in use in an auto body shop to strip paint from a car in preparation for a new coat. Sandblasting works the same on a metal roof, stripping surface rust away. In short, sandblasting is the process of firing abrasive materials at high pressure onto a metal surface, quickly erasing any paint and rust.
The main drawback is Sandblasting requires a special machine, and while you can rent one at most specialty hardware stores, it costs money as well as extra time to prepare. Heavy-duty protective clothing and goggles must be worn at all times, otherwise the flying debris could cause serious harm. You will also need to buy at least one batch of the fine-grit sand the machine uses, perhaps more depending on the size of the roof.
It is often more affordable and safer to hire a professional sandblaster. There are plenty of mobile sandblasting companies such as Pure Blast that can clear the rust for you. Once completed you can paint over it if you choose and rest easy knowing the rust will not cause further damage.
This form of rust removal uses chemicals rather than high-pressure blasting to eat away the rust. However chemical treatment runs the risk of exposing any holes the rust has caused. Chemical treatment can remove large patches on any metal roof types. Because chemicals that can eat away rust are quite dangerous, this treatment must be purchased at specialty metalworking stores. It is sprayed onto the affected area of the roof and left to work for some time. Afterward, washing the chemical away with water will also take the rust right off. These days, most of these chemicals, while strong, are manufactured with the environment in mind. They are meant to be washed away in the outdoors, so you do not have to worry about pollution around the work area.
Conversion spray treatment is the most easily found way to remove rust from a metal roof. It works by converting the rust into a permanent part of the metal and bonding it to the roof.
The spray is applied just like spray paint and works quickly. It is available in most hardware stores and is relatively cheap. Just know that even though the rust is gone, the area you treat will not retain the strength of the rest of the metal roof. It will hold up to the outdoors but not for very long. It is recommended that any rust treated with conversion spray be given an all-weather treatment and a coat of paint in order to keep the roof in good condition.