Sheet lead and copper have been soldered into flat-seam roofs for centuries—long before Thomas Jefferson’s 1740s roof at Monticello—but the more common metal roof type is the standing seam. Here, long panels of metal 24” or so wide are first bent up about 1 ¼” along both edges. “These panels can be roll-formed right on site,” explains Michael Papania of Heather & Little Ltd. in Ontario, Canada, “with custom lengths to fit the roof.” Next, the panels are placed side-by-side and joined in a seam (along with tabs that anchor the metal to the building) by crimping a folded strip of metal over the up-turned ends. This creates a joint that stands high enough above any running water to avoid leaks. Economical and highly durable, standing seam roofs have been popular in the South for all styles of gable-roofed houses since the mid-19th century, and are often seen, wholly or in part, in the North and Canada where snow and ice dams are a chronic problem. “A low-slope roof is the perfect candidate for a standing-seam panel roof,” adds Papania, and indeed standing seam is the traditional choice for porches as well as on low-pitched, modern-style houses.
Standing-seam metal roofs once made by the thousands in terne metal (a tin alloy plated to steel sheets) have given way in recent years to pre-painted steel, but copper still reigns as the king. “Despite being one of the most expensive metal roofing materials, copper is widely used due to its lifespan,” says Papania. “When professionally installed, a copper roof can last 100 years. The mechanically fastened standing seam is the most popular copper profile.”
Add to the mix the sheet metal shingle. Promoted as early as the 1870s as practical melding of metal’s economy with the richness of slate, metal shingles were immediately popular across the U.S. and into Canada for mid-priced houses of all ilks. Rectangles of sheet steel embossed with decorative chevrons or even maple leaves that add rigidity, like slate, metal shingles are installed on steep-slope roofs and show best on large, multi-gabled roofs. Metal shingles are made today in decades-old as well as new patterns. “Stamped metal shingles are gaining popularity in residential roofing,” says Papania. “Installed much like asphalt shingles, they are available in copper, pre-painted steel, galvanized steel, and galvalume, and can be made to look like traditional shingles as well.”
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