Copper rain gutters turn green as a corrosive reaction to certain elements in the air. Those closer to the ocean and urban environments typically turn green quicker because of increased salt and pollutants in the environment. Learn more about this chemical process and the function it serves in the following guide.

The Oxidation Process

A copper rain gutter is exposed round-the-clock to elements in the atmosphere. Copper oxidizes moisture and oxygen upon contact—the copper loses electrons while the oxygen gains electrons. In scientific terms, this is a three-step process: First, copper oxidizes into copper oxide, then into cuprous or cupric sulfide, and finally into copper carbonate. As this process evolves, the copper typically takes on a blue-green hue, called a patina. The Statue of Liberty’s patina is responsible for its iconic green color.

Timeline

There is no hard and fast rule when it comes to how long oxidation takes. In a humid environment with more moisture in the air, a copper gutter will oxidize and develop a patina faster than it would in a dry setting. In general, rain gutters exposed to salty air will take seven to nine years to develop a patina.

The Protective Capabilities of a Patina

Copper patina protects the surface from further corrosion. In salty-air environments, the surface patina typically contains copper chloride, which produces the greenish color that rain gutters adopt. Ultimately, this not only makes for an attractive and distinctive-looking gutter, but also protects the metal.

Amakua Raingutters has more than 12 years of experience providing copper rain gutters to home and business owners throughout Oahu. In addition to gutter installation, they offer repair and cleaning services. Call (808) 258-6994 to request an estimate for new rain gutters, or visit their website to learn more about their products and services.