Corten Steel in the Raw, or Not?


Corten steel, also referred to as weathering steel continues to be a popular material for its artistic appeal, warm variated color tones, and strength, with little to no maintenance. Because this live material is very unique, choosing corten steel often requires some thought. Let’s take a closer look at raw corten steel and what you should know. Our unique anti-washout treatment and our corten steel alternative, a proprietary powder coat color called Corten Colour may be just what you’ve been looking for. This information will help guide your choice between raw or not. Each option aims to address different site-specific concerns.


Corten Steel (Raw)

Raw corten steel, because of the unique process of maturation/oxidation that characterizes it, is considered a “live” material. This material may vary over time in shades and hues depending on the shape of the object, the position in which it is installed and according to the cycles of weathering to which the product undergoes. This oxidize “leak,” while part of the natural process, can stain certain surfaces such as concrete. The stabilization period of oxidation to reach maturity is generally 12-18 months. Once fully matured (has a protective layer of rust), corten steel is virtually maintenance free.


Anti-Washout Treatment

We offer an anti-washout treatment that will reduce the loss of oxide by up to 95-99% and thus reduce the opportunity for staining on adjacent surfaces. It will not completely block losses, but it will significantly decrease the oxide leak. This factory applied treatment gives the product a darker appearance similar to that of fully matured corten steel. This treatment is a standard for only our seating products and must be specified for other corten steel products such as bollards, bike racks, planters, litter bins, barriers, bench supports and bbq’s to name a few. Additionally, this treatment makes for an attractive option for customers who want that rich patina on day one.

In most cases, this treatment does not need to be re-applied as it is only slowing down the stabilization process. The process continues as the treatment wears and thus the material is normally fully stabilized negating the need to re-apply. The best way to describe when to re-apply is if visually the corten steel is “winning” the battle against the treatment. Sounds funny, but it’s true, If that happens or if you wish to re-apply for any reason it is easy to procure and simple to apply. Once fully matured, corten steel is virtually maintenance free.

Corten Colour (Powder Coat Alternative)

In the event you cannot risk using raw corten steel consider Corten Colour. This proprietary powder coat color closely resembles the look of fully matured corten steel and/or corten steel when treated with our anti-washout treatment. Our high-quality steel is first galvanized for optimal corrosion resistance and then powder coated. The outcome is a deep rich brown with just the right amount of overlaying black tones that imitate the appearance of corten steel. In fact, because it looks so similar Corten Colour works in harmony with weathered steel that may be used in different applications within the same site.

We invite you to contact our knowledgeable staff for solutions on your next project. We offer formal presentations to the architectural and design community. Please reach out if you’d like to organize a meeting.