Are you considering a metal roof as your new roof? Are you concerned about rust on a metal roof? Your concern is warranted. Read through the following sections to learn more about metal roofing and the possibility of it rusting.
What Metals Are Used for Roofing?
The four metals that are commonly used for roofing are steel, aluminum, copper, and zinc. The only one of these that will produce red rust is steel, and coatings are available that reduce this possibility to near zero. It is important to mention that expertise is required in putting metal on a roof. An excellent job must be done to ensure that you get the maximum life out of your roofing. Maintenance of the roof is important also. It is possible your metal roof could last for 60 to 100 years.
It is a concern that metal roofing may make more noise than other roofing materials. With all the above 4 materials, the roofing can be applied to be noisy if your preference is to hear the ping of rain and hail. It is also possible to apply the roofing in such a manner that you will hear no more noise than with asphalt shingles or other roofing materials.
Steel Roofing
Steel is probably the most common type of metal used in roofing in the US. The kind that we see in many older commercial buildings has a coating of zinc oxide to prevent rust. It is becoming more common to use steel in roofing, and to paint the material for aesthetic purposes. A wide variety of colors is available for steel roofing.
The substrate for the paint is an important consideration. The most popular substrates for a steel roof are zinc and a product called galvalume, a mixture of aluminum and zinc. The galvalume is the better product for your painted metal roofing material. The Metal Construction Association has advertised that the galvalume product will give a serviceable roofing life of 60 years. This assumes that the roof is installed correctly and receives quality maintenance.
Aluminum Roofing
Aluminum will not rust like steel, though it will oxidate over time. Most aluminum put on housing is painted to provide an extra layer of protection from the elements. If aluminum is left its natural color, it develops a coating which is sometimes called rust. This coating is of a white color, similar to that of aluminum. It is of note that aluminum is often the roof coating of choice in coastal areas, due to it’s long-term resistance to rust. Coastal areas are known for their high levels of rainfall and saltwater spray conditions.
Copper Roofing
Copper doesn’t rust, but over time will develop a coating due to exposure to the sun and oxidation. This coating develops as a colorful patina and can vary from dark bronze to a greenish-blue color. Copper is very expensive, and for this reason is often only applied to special areas of the roof.
Zinc Roofing
When zinc roofing is exposed to carbon dioxide and moisture (our atmosphere), it forms a protective layer called zinc carbonate which eventually has a patina color from dark grey to blue.
Bottom line: metal roofing is a safe and long-lasting material!
While there are many types of metal roofs, they are designed to be outside in the elements for decades at a time. Metal roofing materials may have color variation over time, but they will not rust in the same ways as other metals. So don’t let fear of rust keep you from experiencing the many benefits of metal roofing!
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