The layer of rust is not only appealing in terms of design (colour and texture) but also serves a protective function (hindering corrosion). The protective oxide layer seals the surface and even if chipped or damaged, Corten has the ability to repair itself as a new layer of protective oxide starts to form immediately and with further exposure to the elements. This circumstance grants a continuous protection with a varied appearance: The rust finish is reactive, therefore no sheet ages the same way. Instead each sheet develops a unique finish over time. An additional side effect brought about by the rust is a very low solar reflectivity.
Cor-ten is therefore very low in maintenance and has a particularly long life cycle, making it an attractive material to work with. Although more expensive when compared to common steel products, the fact that Corten steel sheets do not require painting reduces costs.