Why Does Corten Look Different - and What To Expect as it Weathers

When corten steel edging arrives, many people are surprised to see that it looks nothing like the warm, rust-coloured finish they expected. Instead, it’s usually a plain, greyish steel with a raw, industrial look. Don’t worry—this is completely normal.

Corten steel is designed to weather over time. The rusty finish that makes it so popular in landscaping develops gradually through exposure to the elements. Here’s what you need to know about how it changes and how quickly you can expect results.

What It Looks Like at Delivery

Corten edging typically arrives in its raw form, meaning:

• It's grey or silver in colour
• It may have slight mill scale or surface oil
• There's little to no rust visible

At this point, the steel hasn’t begun the weathering process yet.

How It Will Change Over Time

Weeks 1–4: Initial Reaction

• Surface begins reacting to moisture and air
• Small spots of orange or brown rust may appear
• The finish will look uneven or blotchy—this is expected

Months 1–3: Rapid Weathering

• Rusting accelerates, especially with regular exposure to rain, dew, or sprinkler systems
• The colour shifts to more noticeable orange and reddish tones
• Areas exposed to more moisture will weather faster

Months 3–6: Developing Character

• The patina starts to darken and become more uniform
• Rust tones deepen from bright orange to burnt orange and brown
• The steel surface becomes more matte in appearance

6–18 Months: Fully Weathered

• A stable, protective rust layer is formed
• The patina becomes more consistent in tone and texture
• Final colour varies by climate—drier climates tend toward lighter rust, wetter areas toward deeper browns

Tips to Manage the Weathering Process

• Moisture matters: Regular exposure to moisture speeds up the process. If weather is dry, occasional misting can help.
• Pre-weathering: Some people pre-rust corten using a vinegar and hydrogen peroxide spray for faster results, though natural weathering is more even and durable.

Don't Worry - Give it Time

The transformation of corten steel is a gradual and natural process. While it may look plain when it arrives, give it time. Within a few months, you'll start to see the rich, rustic patina emerge—and over the course of a year or so, it will settle into its final, long-lasting finish.

Patience pays off. The result is a beautiful, low-maintenance material that enhances any landscape with organic texture and timeless appeal.