Copper Roofing Petina


Copper Roofing is unique when it comes to roofing materials as it develops a protective copper roofing patina over time. Unlike iron that rusts and deteriorates as it ages under wet and airy conditions, copper undergoes a chemical change where it actually coats itself in this patina. When first installed the copper roof will be shiny like a new penny however over time the roof will slowly brown and will eventually and green phases is an oxide-sulfate patina or coating that’s building up. This coat preserves the underlying metal and prevents it from corroding like most other exterior metals do eventually.

How long this will take is dependent on atmospheric oxidization. The effects of water, light and atmospheric pollutants all contribute to a molecular process that builds copper carbonate on the exposed side of a copper roof.

Copper Roofing Patina
Copper Roofing Patina


The green patina is a highly prized look that people wanting a copper roof desire.  In Fact a common question from anyone considering having a copper roof installed is, “How long does it take for copper to turn green?” The Green Copper Roofing Patina is the mature stage of the copper roofing aging process and can take place at various rates depending on atmospheric conditions.

The main contributing factor or how long it will take is the location it is installed. Location refers to the environmental conditions in the area the copper roofing system is installed. Humidity, salt in the air, water exposure, pollutants all effect on how long it takes for copper to go green from its bright, shiny new state.


Copper changes color much faster in damp and humid climates. Conversely, a copper roof will take longer to get its patina in dry and arid areas. Acidity in the air or acid rain also have a big effect on copper roof patina progression. Areas with precipitation of a pH less than 5.5 will age copper much faster than alkaline climates. So will areas with heavy industrial pollutants. Likewise, copper roofs within city limits get their patina quicker than buildings in a fresh rural area.

Copper roofs oxidize far faster in marine environments. Salt air is notorious for aging copper in a hurry. Copper roofs close to the sea can go from new to looking like they’re ancient in under a decade. It’s not only the exposure to calcium in the air. Structures near shorelines are usually exposed to other elements, especially the wind. But once it builds its healthy patina, copper will withstand many lifetimes of nature’s abuse.

Copper Roofing Patina


Under normal conditions, there is no need to clean a copper roof. Pressure washing and hard scrubbing which will disturb the patina’s natural protection are not recommended. Regular hosing down is sufficient copper roof care. It’ll get rid of bird droppings and other grime

However, some purists want to see a fresh coppery look every few years. The best way to clean a copper roof without removing the finish is to use an organic, citrus-based cleaner, along with clean water and a soft brush. There are many commercial copper-cleaning products available in building supply stores. It’s important to get professional advice from a roofing company that specializes in installing copper roofs. They’ll know the right way to keep your copper roof clean and prevent damage.

Some copper roofing products come factory-treated to keep your roof looking new and freshly cleaned. Polyurethane treatment keeps a copper roof shiny for a few years, but will require reapplying every so often. Otherwise, copper will do what it does best, and quickly oxidize and turn green.

With 20 years of Metal Roofing Experience, Alpine Sheet Metal Systems can install a Copper Roofing System or Copper Guttering System on your residential or commercial property. Over time the copper roofing patina will be a welcomed architectural feature which will make your property stand out.