Eight Things People Believe About Metal Roofs

Most opinions about metal roofing come from barns, sheds, and old installations. Modern residential metal roofing is a different assembly, installed over a deck, over underlayment, over a vented attic. When people compare metal to shingles using a pole barn as the reference, they get most of these wrong. Here is where each belief comes from and what is actually true, calmly, with the sources.

"Metal roofs attract lightning"

They do not. Lightning strikes are decided by height, shape, and location, not by roofing material. The National Weather Service and the Metal Roofing Alliance both say so plainly. If lightning does strike a house, a metal roof spreads the energy and does not ignite, which is better than a shingle roof does. Your roof does not change your odds. There is a longer version in the lightning article.

"Metal roofs are loud in the rain"

A barn is loud. A house is not. The noise comes from panels screwed to open framing with nothing behind them. Over solid decking, underlayment, and an insulated attic, a metal roof measures within a few decibels of asphalt. The honest exceptions are cathedral ceilings, finished attics, and hail, which is louder on any metal roof. Are Metal Roofs Loud? goes through each.

"Metal roofs kill cell and Wi-Fi signal"

Signal is driven by distance to the tower, the layout of the house, wall materials, insulation, and where the router sits. The FCC lists those factors, and the roof is a small one. If a house already has weak signal, the roof is rarely the cause, and a repeater or a mesh system fixes a signal problem regardless of what is overhead.

"Metal roofs rust out"

Old unpainted galvanized roofs did, eventually. Modern residential steel is Galvalume-coated and finished with PVDF paint designed for decades of exposure. Where I see rust on a newer roof, it is almost always one of three things: panels cut with an abrasive saw so hot filings rusted in the finish, dissimilar metals in contact, or a bare cut edge that was never hemmed. Those are installation problems. Near salt water, the right material is aluminum, and we do not install in those markets.

"Metal roofs dent easily"

Impact resistance depends on profile and thickness. Our systems carry a UL Class 4 impact rating, the highest available. Large hail can still leave cosmetic marks on a broad flat panel, and a dent is not a leak. I would rather you know that than be surprised. Many insurers offer a discount for an impact-rated roof, commonly cited in the 10 to 35 percent range on the premium, and that is worth asking your agent about.

"Metal roofs make the house hotter"

The opposite. Asphalt absorbs heat. Metal with a reflective finish reflects it and releases what it absorbs quickly. The Department of Energy's cool roof material describes the mechanism. Attic temperatures come down, and cooling costs are commonly cited at 15 to 30 percent lower. In our climate the yearly effect is smaller than in the South, and ventilation matters as much as the roof. The energy article gives the honest number.

"Metal roofs are too heavy for the house"

Metal is roughly half the weight of asphalt shingles per square foot. Structural concerns on a re-roof are almost always existing damage, not material weight. Weight is not a reason to avoid metal on any normal house.

"Metal roofs are always too expensive"

Metal costs more up front. Asphalt costs more over time. A shingle roof lasts 12 to 20 years and gets replaced two or three times in the life of one metal roof, with each replacement costing 45 to 60 percent more than the last at 3 percent annual inflation. Metal does not cure inflation, but it fixes your roof expense for the rest of your time in the house. The cost article walks through the math with the reasoning.

What I would want you to take away

Most of these beliefs were true of a building that is not your house. Clearing them up does not mean metal is right for you. If you do not plan to stay long and resale is not a priority, a metal roof probably is not necessary, and there is nothing wrong with choosing a cheaper roof as long as you understand it is temporary. Long-term homes deserve long-term thinking. Everything else is renting your roof from the future.

Now you have the facts to decide with.