David Martin is intrigued with the idea of replacing his existing roof with a standing-seam metal roof. It should last longer than the alternatives, he says, and it would be compatible with photovoltaic panels should he decide to add them in the future.
So what’s the issue?
David Martin is troubled by some of the advertising claims he’s seen about metal roofing, specifically a statement from the Metal Roofing Alliance that a “cool metal roof can save 25% in energy costs compared to a dark grey asphalt shingle.”
“I’ve searched around the Internet and found a lot of the industry’s advertising,” David Martin writes in a post at GBA’s Q&A forum, “but I’m a bit skeptical, especially after reading what [GBA senior editor Martin] Holladay says about the dubious claims made by manufacturers of bubble foils, radiant barriers, and open-cell spray foam.”
It seems to David Martin that the biggest variable in energy efficiency is whether they roof is vented. “I figure there would be a negligible benefit, if any, on a vented roof,” he says. “On an unvented roof, would the benefit be comparable to a radiant barrier on the underside of the rafters?”
His questions about the energy benefits of a metal roof are the subject of this month’s Q&A Spotlight.
Rating the cool factor
David Meiland also likes metal roofing — for its durability, recyclability, and ease of removal if the need arises. But he suspects that light-colored asphalt roofing would perform similarly, with or without ventilation. “Comparing a ‘cool metal roof’ and ‘dark gray asphalt shingle’ is apples to oranges,” he writes.
Kevin O’Meara says the difference…