Many people have heard of aluminum anodization and are curious whether anodized aluminum is used in metal roofing. Most aluminum used in roofing, though, has a baked-on paint finish rather than anodization. The leading finishes used on aluminum roofing are Kynar/Hylar based finishes. Generally, there would be some cost advantage to using anodized aluminum.
Anodized aluminum has been used for roofing in the past. However, based upon current technology and capabilities, Kynar/Hylar paint finishes carry superior warranties. Additionally, there is more color variety available with paint coatings. And, while anodized aluminum tends to craze when it is formed, the Kynar/Hylar finishes are very formable without cracking or crazing.
Anodization tends to leave the aluminum with a “metallic” look that would be objectionable to most property owners. Kynar/Hylar finishes, on the other hand, are available in low gloss formulations for a very natural look.
Some people inquire as to whether aluminum could be anodized before it is painted. Generally, due to the fact that a painted surface provides similar protection, there would be no point in doing this. Just the same, the results of applying paint to anodized aluminum are somewhat unpredictable and are not currently warranteed by any paint producers.
In summary, it is the commonplace conclusion within the industry that pre-painted aluminum is superior to anodized aluminum for roofing.