Cor-Ten is almost pure steel, alloyed only slightly to form a protective layer of patina when exposed to weather. The patina layer is initially reddish brown in colour, becoming darker in tone over the course of time. In industrial and aggressive environments, the patina forms more rapidly on the steel and darkens more than in cleaner rural environments. The protective patina layer cannot form, however, if the surface of the steel is continuously damp or dirty.
There are different grades of Cor-Ten available on the market and it’s important to use correct grade for façade applications. Moreover, it is important to understand Cor-Ten behavior in all interfaces to avoid accelerated corrosion, which can lead to significantly shorter life span. To ensure long lasting Cor-Ten façade, we always use Cor-Ten material thickness 1.0 mm or thicker.
Cor-Ten products are delivered un-patinated and the oxidation process starts immediately when exposed to weather. To speed up the process Cor-Ten surface may be washed with water and mild detergent, but finally it is the environmental conditions that are in charge of the process.