Corten steel vs Mild Steel (Classic)

Corten Steel vs Mild Steel – Which Is Better for Your Project?

At Eden Steel, we work with a wide range of materials to suit architectural, structural, and decorative applications. Two of the most common choices are Corten steel and mild steel — each with unique qualities that make them suitable for different types of projects.

In this guide, we’ll explain how these materials differ, what makes Corten steel special, and how to decide which one is right for your needs.

What Is Mild Steel?

Mild steel is a low-carbon steel known for its strength, versatility, and ease of fabrication. It’s used widely in construction, fabrication, and general engineering because it’s easy to cut, weld, and shape.

However, mild steel has little to no corrosion resistance. When exposed to moisture and oxygen, it rusts quickly unless it’s painted, powder-coated, or galvanized. For indoor use or sheltered environments, mild steel performs well — but outdoors, it requires regular maintenance to prevent corrosion and maintain appearance.

What Is Corten Steel?

Corten steel, also known as weathering steel, is a special alloy that contains small amounts of copper, chromium, nickel, and phosphorus. These elements allow the steel to form a stable, self-protecting layer of oxidation when exposed to the atmosphere.

This surface layer — known as a patina — develops naturally over time, giving Corten its distinctive rusted appearancewhile also sealing and protecting the material beneath. Unlike the flaky rust on mild steel, Corten’s patina is tight-bonded and weather-resistant, preventing further corrosion.

Durability and Maintenance

The key difference between Corten and mild steel is how they handle exposure to the elements.

Mild steel needs to be coated to prevent rusting and will require ongoing repainting or maintenance throughout its life.
Corten steel is designed to weather naturally, forming its own protective layer that requires no paint or coatingsonce the patina has formed.

This makes Corten steel ideal for outdoor structures, cladding, and landscaping features where low maintenance and long-term durability are essential.

Aesthetic Appeal

Corten steel’s evolving colour and texture make it a favourite among architects, designers, and landscapers. Its surface changes gradually from orange-brown to deeper, earthy tones as the patina matures — creating a natural, organic lookthat complements both modern and rustic designs.

Mild steel, by contrast, typically requires a painted or coated finish for visual appeal and protection. While this allows for colour choice, it lacks the natural warmth and texture that Corten develops over time.

Cost and Value

Corten steel generally comes at a higher initial cost than mild steel, but it offers better long-term value thanks to its low maintenance and longevity.

Mild steel is more cost-effective for internal or short-term applications, or where a painted finish is preferred. For outdoor installations, however, Corten’s ability to weather naturally often makes it the more economical choice over the life of the project.

Common Uses

Corten Steel Applications:

Architectural cladding and facades
Garden planters, edging, and screens
Retaining walls and landscape structures
Outdoor sculptures and art installations
Signage and decorative panels

Mild Steel Applications:

Structural framing
Fabricated components
Indoor fixtures and furniture
Painted or galvanized outdoor structures

Comparison at a Glance

Feature	Mild Steel	Corten Steel
Corrosion Resistance	Requires coating or paint	Forms natural protective patina
Maintenance	Regular upkeep required	Low maintenance
Appearance	Painted or industrial finish	Rustic, evolving patina
Longevity	Shorter in outdoor use	Extremely durable outdoors
Initial Cost	Lower	Slightly higher
Long-Term Value	Moderate	High

Why Choose Corten Steel from Eden Steel

At Eden Steel, we fabricate and supply Corten steel for both structural and decorative projects across the UK. Our team understands the specific requirements of working with weathering steel — from cutting and welding to surface conditioning and finishing.

Whether you’re creating a feature wall, garden screen, or architectural façade, we can help you achieve the distinctive look and performance that Corten steel offers.