Cor-Ten is a solid steel that has a natural, rugged patina that ages continuously in a unique way. When used correctly it is expressive, long-lasting and maintenance-free. It is also 100% recyclable. 

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.

We in Ruukki have been delivering Cor-Ten facades for over 25 years and are able to help you to design and build a long lasting high quality Cor-Ten façade.

Cor-Ten finishes

Material information

Surface treatmentMaterial thickness (mm)Corrosivity category UV resistanceMinimum order amount (m2)
Patinated (no coating)1.0, 1.5C4n/aNo limits

Material thickness 1.5 mm is used in Liberta & lamella products and 1.0 mm in design profiles.
UV resistance describes how well the coating is able to keep its original colour and gloss levels in accordance with EN10169. The higher the class, the better the resistance.
Corrosivity categories describe the outdoor climate conditions in accordance with EN12944. The higher the category, the more corrosive environment.
Read more about corrosivity categories

Cor-Ten in use

    Facade cladding products available in Cor-Ten

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