Copper and Aluminum Metal Roofing

Copper Roofing

Hildesheim Cathedral

Copper has been used for centuries for statues, art, tools, and roofing.  There are so many examples but I just want to share a couple to illustrate the longevity and durability of copper. 

​The first great example is the Hildesheim Cathedral in Germany.  It was built in 1020 with the copper roof installed around 1280. The roof maintained it's beauty and strength until 1945 when the building was destroyed by an air raid during WWII.  665 years on a roof and I'm sure it could have lasted even longer!  Today the rebuilt church has a great copper roof with a natural aged patina that will last for another century.

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Kronborg Castle

Christ Church in Philadelphia

Another great example of copper roofing is the Kronborg Castle in Denmark. It was constructed in the 1420's and was expanded to the iconic castle in 1585 where it received it's copper metal roof. In 1629 much of the building was destroyed by a fire but was rebuilt. In 2009, it completed a modern restoration where part of the roof was replaced with copper. 380 years for a roof is pretty good and I'm sure it will last for hundreds of years to come.

In America, there are several great examples of copper roofs lasting hundreds of years. One of the most well know is the Christ Church in Philadelphia. It was built in 1744 (32 years before the birth of our country!). The copper roof continues today with a wonderful natural green patina; over 276 years old and going strong.

There are many other great examples but I think you get the point. Copper roofs are long lasting. Unlike iron, which corrodes and rusts as it ages becoming weaker, copper doesn't corrode. As it ages, it actually undergoes a chemical change that it coats itself and goes from the shiny bright copper color to brown to black and then to an oxide-sulfate patina green. Have you looked at a new penny and a really old penny, you can see that chemical change and color change. That chemical change actually helps continue to preserve the metal and give it the long lasting characteristic that many metals do not have. This process of changing color depends on many environmental factors (rainfall, sunshine, atmospheric pollutants, etc.)

Copper Metal Roof

Aluminum Roofing

Aluminum also has a great history of success in roofing. This naturally occurring element is abundant in earth and is highly recyclable (think about soda cans). Like copper, it does not corrode and is can last an extremely long time. I'll share a couple examples of how aluminum is being used in roofing.

One of the earlier examples of aluminum being used for roofing is the Chief Secretary's Office in Sydney, Australia. The building was completed in 1880 and the dome covered in aluminum in 1896 becoming one of the earliest buildings to use aluminum this way. 124 years later and going strong. 

Another example is Dome of the Rock in Jerusalem, Israel. This iconic building was built around 692 and has undergone many different changes. The dome itself has been covered or painted many times over the years including gold plating. But what's better than gold, aluminum! In 1965, as part of the renovation of the building a new aluminum bronze alloy was used and then covered in gold leaf (super thin layer) which gives it the gold color appearance. Before 1959 the dome was covered in lead that turned black. A very drastic difference with aluminum creating the longevity, strength, and light weight needs of the buildings dome.

Today aluminum is manufactured in rolls (standard is 0.032 inches thick) and can be coated and painted and used in many different roofing applications. With the metal properties that don't allow aluminum to corrode, extremely long life, lower cost than copper, and flexibility to be coated/painted it is becoming a preferred metal for roofing. In coastal (near oceans, <1 mile) locations, aluminum is a choice that will endure salt air and the corrosive environment. 

Aluminum Metal Roof

Chief Secretary's Office

Dome of the Rock