Copper: elemental design

    Copper shows its mettle as an eye-catching feature when used both outside and inside a home. Copper turns ordinary house shutters, roof vents and guttering into extraordinary architectural details, while fireplace surrounds and bookshelves clad in the metal cast a warm glow. 

    More opulent options, such as outdoor copper cupolas, dormers and finials, give a home character that will last for more than a half-century, yet will never go out of style. The longevity and beauty of copper make it a popular choice for some homeowners, says Andy Kireta Jr., vice president of building and construction for the Copper Development Association, based in New York City.  

    “People select copper because it is maintenance-free, and once properly installed, it easily lasts 80 years or more,” he says. “Copper’s patina achieves a beautiful array of colour and its reflected glow creates a warm, inviting look.”  

    Copper is a soft, orange-brown metal that has been used by humans for at least 10,000 years. It is malleable and ductile in its pure form and is considered a semi-precious metal. 

    Although most commonly found on high-end houses with copper roofs, copper architectural details can become adornments on any home, says Erno Ovari, a German master craftsman in copper and president of Copper Exclusive near Salt Lake City.  

    “Copper dormers, finials and cupolas are most often ornamental details on American homes,” he says. “These design details are like the jewellery on the outside of the house.” 

    Ovari says you can expect to pay up to two times as much for copper as you would for the same product made of galvanized steel (steel coated in zinc). But, he says, you can also expect copper to last a long time and develop a patina and character as it ages. 

    Copper’s patina refers to the colour change the metal goes through as it ages, forming copper oxide. The rate at which copper gathers its patina is determined by the moisture and sulfur content in the atmosphere.  

    Left alone, new copper will stay shiny, and then transition to a dark brown “old penny” colour. As the copper continues to patina, it will slowly change from brown to verdigris, the green copper colour most familiar on the Statue of Liberty. 

    Kireta says there’s market growth in the use of copper inside the home when used for tubs, sinks and framing windows. “Copper has antimicrobial properties,” he says. “There is more interest in having door knobs fashioned from copper for that reason alone. The aesthetics of copper are an added bonus.” 

    Professional installation is key to ensure copper objects like guttering, roof vents, flashing and chimney caps not only look good, but also function properly. On some installations, it’s important for copper craftsman to wear gloves when handling the metal, because oils from the hands can leave fingerprints or other impressions that will become more visible as copper ages.  

    The natural weathering of copper results in the formation of copper salts on its surface. Outside, these salts mix with rainwater and if allowed to run onto other materials — such as cement or stucco — may cause green stains. To prevent such stains, the use of overhangs, gutters and drip edges are all recommended, Kireta says. 

    “A good installation of copper shouldn’t require caulks and sealant,” he says. “A coppersmith will create a waterproof seal by the way the metal is crimped and detailed.” 

    Quality craftsmanship includes soldered seams over rivets. Also, handmade copper pieces cut with tin-snips may not produce the precise fit required to keep water out and provide structural integrity. It’s better to get copper that has been cut with a computerized water jet, where every cut produces an exact, precise part. 

    To identify quality copper pieces, make sure the material is 99.9 percent pure copper or, at least, a 16-ounce copper. Copper readily combines with other elements, and Kireta says there are at least 400 copper alloys. Some of the most common alloys include a combination of copper and tin, which makes bronze and copper and zinc, which comprises brass. 

    “Copper is a sustainable product, since it is so easily recycled,” Kireta says. “In fact 75 percent of copper used in America has recycled content.” 

    Kireta says copper in its pure form is very malleable, so make sure the copper that is being used has been “cold-rolled” at the mill. Copper is more bend-resistant and strong after it has been stretched. 

    “Quality copper pieces installed properly will give a home a lifetime of service,” Kireta says. “The homeowner isn’t going to have to work to maintain copper details, and in some cases, those architectural details last longer than the home itself.”