Why Does Copper Turn Green Over Time?

Copper naturally turns green over time as it reacts with oxygen in the air – a chemical reaction known as oxidation. The green colour is simply the natural shade of the patina that forms over the copper surface; the patina protects the copper from deterioration and creates a light bluish-green facade which can be seen on many copper rooftops and copper structures.

How Long does it take Copper to Turn Green?

Copper doesn’t turn green overnight, it transitions through a number of stages over the years, moving from its initial orange shade into a dull brown colour, before finally settling into the familiar green tint.

To demonstrate the timescale of this transition, we’ve used the most famous and iconic example of this process on Earth: the Statue of Liberty. The animation below tracks its changing colour pallette over the months and years since it was first installed on what is now known as Liberty Island:

Copper turning green

  Copper Patina Colour Chart

Copper patina colour chart

The patina which forms over copper works to protect and preserve the underlying copper material. This is different to what happens to iron during oxidation, where rust forms over the surface, deteriorating the material over time.

From the Statue of Liberty to a commercial copper roof, the green patina prevents further oxidation, making copper one of the most long-lasting roofing materials you can find.

JTC Roofing are proud to be a leading supplier and installer of first class copper roofing to commercial and domestic customers throughout the UK. Our specialist team are on hand to provide extensive insight and advice help you find the ideal copper roofing solution for your property, all you need to do is get in touch with us today.



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