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How Long Does a Metal Roof Last?
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Longer than asphalt, and the honest answer depends on which metal roof you mean, because two very different products get sold under the same word. For coated steel generally, the US Department of Defense’s roofing criteria states that in most environments it will render a service life of 40 years or more, and puts unpainted Galvalume in non-industrial inland climates in the range of 40 years, which describes Oklahoma. For exposed-fastener panels, the only published figure we could find is far shorter and it is the fasteners rather than the metal that decide it. Arrowhead Roofing has installed and replaced metal roofs in northeast Oklahoma since 1987, and the number that matters is never the one printed on the panel.
Note: this is a general guide drawing on published studies of specific roof types. Service life depends on the system, the coating, the environment and the detailing, and the figures below are quoted with the scope their sources actually cover. Have a specific roof assessed rather than assuming a number applies to it.
Two systems, and almost every disagreement about metal roof lifespan comes from mixing them up.
| Standing seam | Exposed fastener | |
|---|---|---|
| Where the fasteners are | Concealed under the seam, not through the weather surface | Driven through the panel face, with a sealing washer under each head |
| What usually ends its life | The sealant and the details, not the metal | The fastener washers, long before the panel |
| Published service life | 40 years or more for coated steel. In excess of 60 for one specific low-slope unpainted system | Up to 10 years, from a 2002 study, and see the caveat below |
| What it costs | More | Less |
The Short Answer
The metal is almost never what fails. Coatings, sealants and fasteners fail, and they are all replaceable or maintainable in a way a rusted-through panel is not.
That reframes the question usefully. “How long does a metal roof last” is really “how long until something on this roof needs attention, and is it the sort of thing that can be attended to.”
For comparison, a widely cited home components study puts asphalt shingles at about 20 years. Worth knowing that the same study does not list steel roofing at all, so anyone citing it for a metal roof figure is citing something it does not say.
The 60 Year Number, and What It Actually Covers
You will see 60 years everywhere on this subject. It comes from real research and it is being applied to the wrong roofs.
The Metal Construction Association published a field study whose title states its own scope: low-slope, unpainted, 55% aluminium-zinc alloy-coated steel, standing seam. Its conclusion is that a similar roof built today with best practices can be expected to last in excess of 60 years.
Read the scope again. Low slope. Unpainted. That is a commercial or agricultural Galvalume roof, not the painted standing seam roof on a house. The number is sound and the extension to residential is not ours to make.
The study contains something more interesting anyway. It found that butyl sealant life, not the metal, is the deciding factor in establishing end of life for those roofs. The panels were projected to outlast the building.
The Myth the Field Study Actually Killed
Cut-edge corrosion is usually named as a primary killer of metal roofs. Every sheared edge and every bend, the argument goes, is exposed steel waiting to rust.
The same field study looked at exactly that on roofs up to 35 years old and reported the absence of significant red rust at sheared edges and panel profile bends, describing the corrosion resistance as exceptional.
We are publishing that because it contradicts something we would otherwise have repeated. The edges are not the problem. The details, the sealants and the fasteners are.
The Exposed-Fastener Answer, With Its Caveat Attached
This is the honest weak point in the whole evidence base and we would rather say so than paper over it.
The only published service life figure we could find for a through-fastened panel roof comes from an IIBEC Interface article: depending on the system, such a roof can have a service life of up to 10 years, with the panel finish lasting well beyond that while the exposed fastener gaskets, lap joints and penetrations drastically reduce it.
That article is from 2002. It describes an era when the sealing washers were neoprene, which the same article says would dry and crack after a few weather cycles. The industry has largely moved to EPDM washers since, and the Department of Defense criteria now specifically require EPDM rather than neoprene.
So the figure is real, published, and describes older hardware. A modern exposed-fastener roof should do better. How much better is not something anyone has published, and we are not going to invent a number to fill the gap.
What Nobody Publishes
Three gaps, stated plainly because you will find confident answers to all three elsewhere.
There is no published service life for metal shingles or stone-coated steel. The ranges quoted for them trace back to marketing rather than to research.
There is no published expected life for fastener sealing washers. Not from the standards bodies, not from the trade associations.
There is no published re-screw interval. A fastener manufacturer suggests one in a web article without citing any test basis. That is a vendor’s opinion and it is worth exactly that.
What Changes the Answer
Three things move a specific roof a long way from any published figure.
Which system it is
Concealed fastener or exposed fastener is the first question and it changes the answer more than anything else on this page. You can tell from the ground: if you can see rows of screw heads across the panel faces, it is the second kind.
What the details are made of
Pipe flashings, gutters and fasteners are replacement items on a long-lived roof rather than permanent ones. The MCA study noted that some stainless fastener grades were corroding while others were ageing well, on the same roofs.
What the weather here does to it
Oklahoma is a hail market, and hail raises a question about metal that it does not raise about asphalt: whether a dent is damage at all. Some policies exclude cosmetic damage, and that distinction has its own answer at will insurance pay for hail damage to a metal roof?
Related Questions
It is leaking but the panels look fine. Why?
Usually the fasteners or a penetration rather than the metal. Why is my metal roof leaking if the panels look fine? covers where the water actually gets in.
Does insurance pay for hail dents on metal?
Only certain dents matter, and some policies exclude the cosmetic ones outright. Will insurance pay for hail damage to a metal roof? covers the distinction.
How long does an asphalt roof last here?
Less than the marketing suggests, because this market takes hail. How long does a roof last? covers service life against the local storm record.
See Also
The two answers next to this one are what an asphalt roof does here, and what hail means for a metal roof on a claim.
Find Out Which Metal Roof You Actually Have
We have installed and replaced metal roofs in northeast Oklahoma since 1987, and the first thing worth establishing is which system is up there. Book a free roof inspection and we will tell you what it is and what condition the details are in.