10 Facts about Weathering Steel

Weathering steel is a group of steel alloys, developed to form a stable rust-like appearance after many years of exposure to weather. The advantage of this is to eliminate the need for painting, and also to strengthen the metal.

If exposed to harsh weather a stable rust forms over metal– keeping the inner layer safe and robust by preventing deeper penetration. The rust that develops is an oxidised dark brown coating that protects the metal and prevents further rusting and penetration that could weaken it. You might have heard of it as Corten, which is the trademark name owned by U.S. Steel (often written as COR-TEN®)


Weathering Steel Applications

Corten can be used for many purposes.  It has become so popular as a feature in landscape architecture and sculpture. To form a properly adhered protective layer, Weathering Steel must be exposed to alternating wet and dry cycles.

Building and Architecture: Corten is popular in architectural and outdoor building use.

Art and Sculpture: During the 1950s and 1960s, it became a popular material for outdoor art projects. It is currently commonly used for outdoor sculptures.

In Gardens: Particularly domestic gardens as an alternative to concrete walls.

Visual Screen: Can be used as a structure as well as cladding material to fences.

Exterior Wall Panelling: When allowed an air gap, air can circulate between the exterior wall panel and the structure. While remaining separate from the building structure, it protects it from rain and subsequent water damage.

 Facts about Corten Steel

  1. The mixing of a particular combination of steels and alloys creates Corten Steel. It is the combination that enhances the rusting properties to give the well-known oxidised dark brown look.
  2. It is corrosion resistant and very strong. It has a higher resistance against atmospheric corrosion as compared to other steels. It acts as a protective coating stopping further corrosion on the inside metal.
  3. You can save on painting and expensive maintenance to prevent rust. You neither need to treat nor paint it.
  4. It has a longer life-span than bare cold rolled steel
  5. Weathering Steel continues to rust for a very long time. The process starts after installation and happens at a faster rate at first, and then eventually decreases.
  6. When first installed, it looks black and shiny. After being exposed to some weathering, it first turns a streaky yellow that turns orange. A dark-brown colour forms after the first decade or two.
  7. How does the regeneration finally end? The pores at the rust and steel interface are clogged when the alloying elements in the steel produce insoluble compounds.
  8. Despite its size (it is usually only ¼ inch thick when produced in sheets), it is sturdy and durable.
  9. It is advised not to use this product for roofing or siding when used in architectural or building applications
  10. It is advised not to place it above surfaces that don’t stain or will be disfigured in any way.

Read more on Weathering Steel in Modern Architecture

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