What is Corten Steel?
Corten steel, also known as Cor-Ten, is a brand of weathering steel in which the surface rust layer protects the steel beneath from further degradation.
This natural patina gives Corten steel a longer lifespan compared to mild steel. Our Corten steel edging typically develops its characteristic brown finish within a month, depending on environmental conditions.
While initially designed for industrial applications, Corten steel has become popular among architects and artists-and from there, it made its way into gardens.
At Steelscapes, we were among the pioneers in bringing Corten steel to landscaping, offering products like steel garden edging, woven steel fences, and steel gates.
Mild Steel Edging vs. Corten Steel Edging
Mild Steel Edging also forms a rust layer, which provides some protection to the steel beneath, but degradation occurs more slowly. For example, in fairly aggressive conditions, mild steel loses about 0.01mm (10 microns) per year, meaning even a 3mm thick panel can last decades.
Mild steel takes longer to develop its brown patina-on average, around 10 months-while Corten achieves its patina in roughly 1 month.
Do They Look the Same?
Many clients request Corten steel for its iconic weathered look. However, both mild steel and Corten steel eventually develop similar warm brown tones, making them visually almost indistinguishable once weathered.
Corten steel: Slightly lighter, more orange patina due to copper content.
Mild steel: Slightly darker initially, but develops similar brown shades over time.
Your edging will arrive largely unweathered: mild steel starts darker, while Corten is more metallic and shiny.
Tip: Weathering can be accelerated using a simple rust solution-salt, vinegar, and water, or by adding 3% hydrogen peroxide (food grade). A conservative recipe: 2 cups peroxide, 4 tablespoons vinegar, and 2 liters of water. Apply by painting, wiping, or spraying.
Cost Considerations
Corten steel edging is more expensive than mild steel, on average 65% higher. The higher price reflects the cost of Corten production and the laser cutting required to form various edge sizes.
Mild steel edging is far more cost-effective and performs well in most garden applications, while Corten is recommended in specific scenarios:
Matching existing Corten features, such as raised beds or cladding.
Areas where rust staining would be an issue on light-colored paving.
For lawns, gravel, borders, or tarmac edging, mild steel performs just as well and is the more economical choice.
Corten Steel: Faster weathering, slightly higher cost, ideal for matching existing Corten features or avoiding staining on sensitive surfaces.
Mild Steel: Slower to develop patina, more affordable, excellent durability for most garden edging applications.
In most garden settings, mild steel edging provides excellent service life, while Corten steel is best for aesthetic matching or where staining needs to be controlled.
