Copper is one of the oldest metals used in human history. In an era archaeologists call the Copper Age, skilled craftspeople smelted a malleable, orangey-brown material into tools and weapons. Metallurgy improved by leaps and bounds over the centuries, and it wasn’t long before copper became a mainstream building material, particularly on the roofs of upper-end structures like sky-reaching cathedral roofs and spectacular domes.
Some of the world’s most revered and famous buildings have copper roofs — and not just historic, medieval structures like castles and churches. Many of America’s early homes and public buildings still display the unmistakable greenish-blue patina of aged copper on their roofs. And many of the nation’s leading architects immediately specify copper as the No. 1 roofing choice for projects currently on their drawing boards.
American homes and historic public houses built in the 1600s and 1700s have been preserved through multiple renovations. Their exterior siding, windows and doors have been repaired or replaced. So have their interior finishing and mechanical systems. But their original copper roofs remain intact, except for the occasional cleaning and touch-up. That’s because properly installed copper roofs are virtually indestructible.
The age of many copper roofs is a testament that copper isn’t a fad. There are more copper roof installations on luxury homes and high-end commercial buildings now than ever before. Copper is the one roofing material that outlasts the occupants – a copper roof life expectancy is hundreds of years.
Copper roofs aren’t just gorgeous to behold. They’re also incredibly practical. Copper is one of the longest-lasting roofing materials you can install. Craftsmen can easily form it into all sorts of complicated and challenging shapes. Copper’s unique beauty lies in its aging process. What you see as copper ages from its shiny new look through its darkening phases is a natural phenomenon that’s unique to copper.
The Different Types of Copper Roofs
You can install copper roofs on practically every architectural style and building type. It’s open to a designer’s imagination and the installer’s skill. You’ll see copper roofs on luxury homes and on elegant commercial buildings. Some buildings have their entire roof line sheathed in copper, while others have limited accents like a turret or feature awning over a bay window.
While you can add a copper roof can to every type of building design, there are limited types of copper roofing materials. Each one has a specific design intention and installation application. Roofing contractors who are trained and experienced with copper roofing systems are the best sources to advise on what type of copper roof best suits a particular building.
- Continuous copper roofing: This is a specialty application generally designed and prefabricated for an exact job. It involves laying out sheets of copper on a roofing substrate that assembles in one piece without joints or seams. Continuous copper roofing is the most expensive option.
- Copper panels: Panels are less expensive than continuous sheets. They’re sectional copper sheets that arrive in standard widths and are hand-installed with noticeable seams. Some seams are crimped, in a process called standing seam copper roofing. Other seams are brazed or welded onsite.
- Copper roofing shingles: These are commonly used because of their relatively low cost. Shingles are hand-applied — much like any other type of shingle roofing product — but you need to be careful in preventing damage to copper’s soft surface. This method also requires copper fasteners to prevent metallurgical reactions that can happen when other metal products come in contact with copper roofing.
Benefits of a Copper Roof
There are many reasons top-quality builders have used copper roofs for hundreds of years. Professional builders and designers know the benefits of copper, as opposed to lesser roofing materials like wood shakes or asphalt shingles. Premium buildings are capped with copper because there is no other weather protection material that performs like copper.
Here are the main benefits of copper roofs and why some owners specify copper rooftops.
- Architectural appeal is a primary benefit. Copper roofs are elegant, and there is no other way to complement certain architectural styles than blending copper roof shingles or seamless panels with a specific design. Discerning homeowners and designers realize copper roofs will set off curb appeal like no other material. That brings a sense of pride and satisfaction, which is impossible to value.
- Durability is unsurpassed. Copper is the only roofing material that improves with age. A copper roof will withstand all forms of natural abuse, from high winds to torrential rains. As it ages, copper builds up its protective film that works as a barrier or shield. You can’t achieve this type of durability with other products.
- Cost-effectiveness is a proven, long-term benefit. Although copper roofs are initially more expensive than most other roofing systems, they have long-term cost efficiency due to extremely long service life. Where roof materials like wood and asphalt shingles have an approximately 25-year service life, copper lasts centuries.
- Low maintenance is another prime benefit from having a copper roof. Under most circumstances, copper roofs do not require any maintenance. Some owners choose to clean their copper roofs and occasionally freshen them up. That’s a matter of personal choice, but it’s rarely necessary.
- Antimicrobial qualities are present in copper. Uncoated copper and copper alloys have natural qualities that resist fungus and bacteria growth. Copper roofs are mold- and rot-free, which makes them easier to keep clean. Natural rainwater is usually sufficient to wash away dirt and biological contaminants that can’t get a foothold on copper’s surface.
- Lightweight copper roofs weigh considerably less than other roofing products, especially heavy concrete tiles or slate shingles. You can also build roof structural members like trusses and rafters from slimmer materials. That cuts down on overall construction costs. These savings can offset the initially higher cost of labor and materials that go into installing a copper roof. This also lets the building’s structural components last longer due to reduced load stress. Additionally, copper roofs lessen weight in high-snowfall areas.
- Lower thermal movements occur in properly designed and installed copper roofs. There is minimal expansion and contraction when the roof goes through hot and cold cycles. Copper has a high heat threshold, giving these roofs minimal creep and stretch tension. These dynamic forces shorten lesser products’ life spans. Ventilation is also less of a concern with copper roofs.
- Fireproofing is highly important where buildings are at risk of forest fires. Copper roofs are even excellent insurance against catching fire from an adjacent structure. It takes a tremendous amount of heat to distort copper, let alone destroy it.
- High-value retention is a clear benefit from installing a copper roof. Just the visual impact alone supports a higher real estate value. When considered alongside the durability and longevity copper roofs return, high-end purchasers realize the value they receive in purchasing a building with a copper roof.
- Natural and recyclable copper roofs will outlast virtually every other building product. Once the structure is retired, copper from the roof, flashing, gutters and other trim can be reclaimed and recycled. There is extremely high demand for recycled copper.
Copper Roof Costs
There is no set cost of a copper roof. Total costs depend on the style of roof, type of material and amount of coverage. Be careful when you hear someone claim a copper roof will cost a specific amount per square foot. Certainly, when you install your copper roof, you can divide the total bill by the coverage to get a unit figure.
But there are too many variables going into a copper roof for any company to quote a flat rate. The location of your project has a significant bearing, as there may not be any local roofing companies with copper roof experience. Installing copper is a unique skill — the professional craftspeople who do it are well-paid, and deserve to be.
Material costs vary depending on availability and current market conditions. Copper is a highly sought-after commodity, and its raw cost fluctuates according to world pricing. Copper materials go beyond panels, shingles and continuous copper roofing. They include flashings, fasteners, underlays, gutters and downpipes. All these elements work as a system to make a complete and long-lasting copper roof system.
How to Clean Outdoor Copper
The best advice about cleaning copper roofs is not to bother. Normally, there’s no need to ever clean a copper roof. One of the worst things you can do is scrub hard or pressure wash and disturb the patina’s natural protection. Regular hosing down is sufficient copper roof care. It’ll get rid of bird droppings, leaves and accumulated 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.
Why Copper Roofs Change Color
Unlike iron that rusts and deteriorates as it ages under wet and airy conditions, copper undergoes a chemical change where it actually coats itself with a preservative. The gradual slide from appearing as a newly minted penny through its brown, black 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.
Atmospheric oxidization is responsible for copper’s color change. 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. A similar process occurs on the unexposed side of copper materials, but it’s far slower than the exterior, weather-beaten areas.
How Long Does it Take for Copper to Turn Green?
The aged, green patina is what most people find attractive about copper roofs. A common question from anyone considering having a copper roof installed is, “How long does it take for copper to turn green?” Green copper is the mature assurance that this wonder metal has settled in for the long run. The answer to this question, however, is not simple or straightforward. How to get green patina on copper depends on a lot of factors.
The copper-roofed building’s location is the main contributor in how to age copper green. By location, that doesn’t necessarily mean how it’s positioned to the elements, though this does have an effect. All building locations across the country and around the world have different local humidity levels. Humidity and direct water exposure have an inversely proportional effect on how long it takes for copper to go green from its bright, shiny new state.
How Copper Roofs React to Moisture and Humidity
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.
The Statue of Liberty in New York Harbor is an excellent example of how copper stands up to full weather exposure. According to the Copper Development Association, when the Statue of Liberty was renovated for its centennial, the copper cladding needed very little reconstruction work. Unlike its inside iron skeleton that needed major corrosion repairs, Lady Liberty’s bluish-green or verdigris copper skin was in near-perfect shape. Over 100 years of being blasted by the sun, wind, rain and sleet, the patina-protected copper jacket showed less than .005 of an inch of wear.
That amazing durability serves as proof that the Statue of Liberty will keep standing for centuries more. The same occurs with copper roofs. The average lifespan of a copper roof is well into the hundreds of years, provided it’s installed by skilled professionals who know their craft.
Contract With a Copper Roofing Professional
There’s no question about copper roofs being expensive. The initial cost of a copper roof is going to be much higher than a standard roof. However, the long-term benefits and payback have no equal. Copper roofs last many human lifetimes, provided they’re professionally installed.
Huber & Associates has extensive professional expertise in installing and repairing top-quality copper roofs. We’ve completed projects from simple to highly complex. One of the contracts we completed was on the historic Biltmore Estate in Asheville, N.C., which was once the magnificent mansion belonging to the Vanderbilt family.
Huber & Associates are award-winning roofing experts. We specialize in historic roof restoration and can design a beautiful custom copper roof for any building. Learn more about our historic roof restoration products and services. For expert installation and professional workmanship of your copper or other specialty roof, call Huber & Associates today at 828-275-7678.