How Long a Metal Roof Actually Lasts

The short answer is 50 to 70 years or more for a properly installed residential metal roof, against 12 to 20 for asphalt shingles. The honest answer is that "metal roof" covers several different systems, and they do not all last the same. Here is what the number depends on.

The four things that decide it

The system. An exposed-fastener roof has hundreds of rubber washers under its screws, and those washers age faster than the panel. The panel may be good for decades; the fasteners need attention around year ten to twelve, and if nobody gives it, the roof leaks long before the steel wears out. Concealed-fastener systems, standing seam and interlocking metal shingles, have no washers in the weather, so the panel and the coating set the lifespan rather than the fasteners.

The coating. A factory finish applied to the coil at the mill holds color far longer than anything brushed on later. The two we use are AkzoNobel Ceram-A-Star 1050 and Sherwin-Williams WeatherXL, both silicone-modified polyesters. A PVDF fluoropolymer holds color and gloss longer still, and it is what the interlocking shingles carry. A cheap polyester on thin stock is the one to watch — it will chalk and fade in 10 to 15 years. The steel under it is still a roof, but it is not the roof you thought you bought. More on this in coatings.

The environment. Salt air eats steel. For a coastal home the right material is aluminum, and we do not write for those markets. Inland Midwest weather is hard on a roof, freeze-thaw, ice, hail, wind, but it is what these systems are built for.

The install. Flashing done with sealant instead of formed metal, panels pinned so they cannot move, fasteners overdriven, panels cut with an abrasive saw so the filings rust in the finish. Every one of those shortens a roof's life, and none of them has anything to do with the metal.

What shortens it

Beyond the install, a few things I see on roofs that are aging badly:

• Dissimilar metals in contact. Copper flashing or treated lumber against galvanized steel sets up corrosion.
• Debris left in valleys and behind chimneys, holding water against the panel for months.
• Sealant-based details that were never revisited. Sealant has a service life. Formed metal does not.
• Trapped moisture from an attic that cannot breathe, working on the deck from below.

No roof is zero maintenance, and metal is not an exception. What it asks for is less, and less often.

Lifespan is only half the math

A roof has an initial cost, a maintenance cost, a lifespan, and a total value, which is what you paid divided by the years of protection you got. Asphalt wins the first line and loses the rest. At 12 to 20 years, the average homeowner replaces a shingle roof two or three times in the span of one metal roof, and roofing prices do not hold still. They rise about 3 percent a year, and each asphalt replacement tends to cost 45 to 60 percent more than the last.

That is why I talk about cost per year of protection rather than sticker price. Divide what you pay by the years you get, for both, honestly, for your house. The cost article walks through the numbers with the reasoning around them.

Where the long lifespan does not help you

If you are selling in the next few years, a 60-year roof does not return what it costs. Buyers in this market do not reliably pay for it. Asphalt is the rational choice for a short hold, and I will say so.

If you want a roof you never think about again, the exposed-fastener version of "metal" is not that roof. It lasts longer than asphalt, but it asks for a look every year or two.

And if someone quotes you a lifespan without asking what system, what coating, and what slope, they are quoting the material, not your roof.

What "lifetime" means on our side

Our warranty covers materials and workmanship for life, and it transfers to the next owner. It can do that because our crews are manufacturer-certified, which is what lets the manufacturer stand behind the install and not just the panel. What no warranty can do is make a roof maintenance-free.

Now you have the context to decide.