How Long Does a Metal Roof Last? Aluminum vs. Steel vs. Asphalt

Roofing Lifespan Comparison at a Glance

Not all roofs are created equal. The table below compares the typical service life of the most common residential roofing materials. Ranges reflect differences in product grade, climate, and installation quality.

The pattern is clear: metal and stone-based roofs dramatically outlast asphalt. For a deeper cost-and-lifespan breakdown, see our guide to metal roofing vs. asphalt shingles. But among metals, the material itself matters enormously, and that comes down to one word: corrosion.

What Actually Determines How Long a Roof Lasts

Lifespan is not a single number stamped on a product. It is the result of how well a roof resists the forces that destroy it over time. Four factors do most of the work.

• Corrosion and rust — the number-one enemy of metal-roof longevity. Steel is iron-based, so it will rust if moisture ever reaches the base metal through a scratch, a cut edge, or worn-through coating. Galvalume and galvanized coatings slow this, but they are sacrificial layers that deplete over time. Aluminum contains no iron and cannot rust; it forms a stable, self-protecting oxide layer, which is exactly why aluminum is the material of choice in coastal, high-humidity, and salt-air environments.
• The coating system — a roof's finish protects the metal from UV radiation, resists chalking and fading, and shields the surface from pollutants and acid rain. Cheaper paint systems break down within a decade or two, exposing the metal beneath. Premium finishes like the multi-layer Alunar coating are engineered to hold color and integrity for decades.
• Fasteners — a hidden weak point on many metal roofs. Exposed-fastener systems rely on rubber washers that dry out, crack, and back out over time, creating leak points. Concealed-fastener systems, where panels interlock and the fasteners are hidden and protected, eliminate that failure mode and are a major reason quality metal roofs last as long as they do.
• Installation quality — even the best material fails early if installed poorly. Improper flashing, inadequate underlayment, poor ventilation, and rushed workmanship trap moisture and accelerate wear. A roof installed by trained specialists consistently reaches the top of its lifespan range; a corner-cut installation rarely does.

Why Interlock Aluminum Roofs Last 50 to 75 Years

Interlock's expected service life of 50 to 75 years is not a marketing figure pulled from thin air. It is the direct product of the two factors that matter most: the metal and the coating.

Because Interlock roofs are made from aluminum, they will never rust, no matter how many decades pass or how close the home sits to salt water. That single property removes the most common cause of premature metal-roof failure. On top of that, the proprietary Alunar coating uses a 70% PVDF resin engineered for 30-year fade resistance, protecting the aluminum from UV and the elements while keeping its appearance for the long haul.

• Rust-proof aluminum — no iron, no rust, ideal for coastal and harsh climates.
• 70% PVDF Alunar coating — 30-year fade resistance and long-term UV protection.
• 4-way interlock with concealed fasteners — panels lock on all four sides with no exposed washers to fail.
• 120 mph wind rating and UL 2218 Class 4 impact rating — the highest hail-impact class, verified in our testing reports.
• Transferable Lifetime Warranty — protection that follows the home, detailed in our warranty.

Combine rust-proof aluminum, a long-life coating, and a concealed-fastener interlocking design, and you get a roof engineered to outlast the mortgage, and often the homeowner's time in the house.

Being Honest: What Shortens a Roof's Life

No roof is immortal, and it is fair to be upfront about what can cut a lifespan short. The biggest culprits include:

• Poor installation — bad flashing, wrong fasteners, or inadequate underlayment undermine even premium materials.
• Trapped moisture and poor ventilation — a roof that cannot breathe invites condensation, rot in the deck below, and corrosion.
• Severe, repeated impact — large hail and falling limbs can dent or damage any roof, though a UL 2218 Class 4 rating provides the strongest available defense.
• Neglected maintenance — clogged gutters, unaddressed debris, and ignored flashing issues let small problems become big ones.
• Galvanic corrosion — mixing incompatible metals, such as the wrong fasteners or dissimilar flashing, can accelerate corrosion at contact points.
• Cut edges and scratches on steel — on iron-based metals, any breach in the coating becomes a starting point for rust.

The good news is that most of these are avoidable through the right material choice and a professional, system-based installation, which is precisely how the top of a lifespan range gets reached.

The Bottom Line: How Aluminum, Steel, and Asphalt Compare

Asphalt roofs are cheap to install and expensive to keep replacing every 15 to 30 years. Steel roofs last far longer but depend on their coatings to fend off rust, which is the central trade-off explored in our aluminum vs. steel roofing comparison. Aluminum sidesteps the corrosion problem entirely, which is why a well-built aluminum roof with a durable coating can realistically protect a home for 50 to 75 years or more.

For most homeowners, that makes a premium metal roof the last roof they will ever need to buy. If you are weighing the long-term math against upfront cost, our breakdown of whether a metal roof is worth it puts the numbers side by side. Over a 50-year horizon, an asphalt homeowner might buy three or four roofs; an aluminum homeowner buys one.