Naturally, copper roofs will change over time due to exposure to the elements. For some, this is considered part of the metal’s appeal and is why copper is such a popular choice for roofing. The blue-green patina that eventually forms on copper roofs is beautiful and acts as a protective layer against further corrosion.
Why Does Copper Turn Green Over Time?
- Reaction to oxygen
When copper is first installed, it has a bright reddish-brown color. This is because the metal is new and has not yet been exposed to oxygen. However, over time, the copper starts to turn green as it reacts with the oxygen in the air. Oxygen causes a chemical reaction that creates a patina on the surface of the copper.
- Reaction to moisture
Another reason copper turns green is the reaction between copper and moisture. When water hits the surface of the metal, it causes a chemical reaction that creates the green patina. This is why you often see copper roofs on buildings in humid climates.
- Reaction to pollution
Copper can also turn green as a result of exposure to pollution. Sulfur dioxide and other pollutants in the air can cause a chemical reaction that creates the green patina on copper. If the copper is located near a saltwater body, the salt can also contribute to the formation of the patina.
- Reaction to chemicals
Certain chemicals can also cause copper to turn green. For example, using cleaners that contain ammonia or bleach on your copper roof can cause the metal to turn green. Examples of common cleaners that contain ammonia or bleach include window cleaners, oven cleaners, and toilet bowl cleaners.
- Reaction to temperature
Temperature can also play a role in forming the green patina on copper. If the temperature is too cold, the chemical reaction that creates the patina happens more slowly. On the other hand, if the temperature is too hot, the patina forms more quickly. Therefore, the climate in which the copper is located can affect how quickly it turns green.
How Long Does It Take Copper to Turn Green?
The time it takes for a copper roof to turn green depends on several factors, including exposure to oxygen, moisture, pollution, chemicals, and temperature. Generally, it takes a few months to a few years for the patina to form.
Why Do People Like Copper Roofs?
Even though copper roofs turn green over time, many still prefer them because of their beauty and durability. Copper is a very strong metal that can last for decades without needing to be replaced. Also, the green patina that forms on copper roofs is often considered to be attractive. Therefore, it is not surprising that many people find copper roofs a popular choice.
Bottom Line
Dowd Roofing Co. has been installing copper roofs for over 40 years, and we have seen firsthand how the metal changes over time. We understand that some people may find the patina beautiful, while others may prefer a more uniform color. Our team can help you decide if a copper roof is right for your home or business. Contact us today to learn more about our services.