Long Island · Roof lifespan guide
How long does a metal roof last on Long Island?
It depends on the metal, the coating, the fasteners and the installation. Steel lasts about as long as its coating keeps it from rusting. Aluminum cannot rust, and aluminum has been known to last over 100 years. That is a property of the metal, not a promise; what the manufacturer puts in writing is in the warranty, set out below.
Reviewed by Scott Plumptree, Director of Marketing, The Interlock Group · Updated October 7, 2026
The metal
Aluminum has been known to last over 100 years
Aluminum cannot rust. A property of the metal, not a promise.
The material
Guardian Lifetime Limited Material Warranty
Material and finish, for the original homeowner. Transferable once.
The finish
30-year Alunar® coating warranty
On the paint finish that carries the color.
What decides how long a metal roof lasts?
Four things: the metal, the coating, the fasteners and the installation. "Metal roof" covers very different products, and those four decide how long one lasts on your house.
The metal
Steel rusts wherever its protective coating is scratched, cut or worn through, so a steel roof lasts about as long as its coating. Aluminum cannot rust. It forms a thin oxide layer on its own surface, which is why aluminum has been known to last over 100 years.
The coating
The paint finish decides how the color holds up to sun and weather. Interlock® roofs carry a 30-year Alunar® coating warranty on the finish, separate from the material warranty.
The fasteners
Exposed screws through the weather surface rely on rubber gaskets that age in sun and heat. Interlock® panels lock to each other on all four sides with the fasteners concealed, so there is no exposed screw head for water or wind to work on.
The installation
Flashing at walls, chimneys, valleys and skylights, the underlayment, attic ventilation and the slope (every Interlock profile needs a minimum 3/12) decide how a roof performs for decades. Wind resistance is warranted to 120 mph when installed to manufacturer specification, which is why the installer is certified on the system.
What does a Long Island year do to a roof?
It works a roof through nor'easters, freeze–thaw, snow, summer sun and, near the water, salt. Each finds a different weak point.
Nor'easters and tropical storms
Gale-force northeast winds from September to April (National Weather Service) and tropical systems in late summer drive rain sideways under loose tabs. Interlocked panels leave no tab edge for wind to lift; wind resistance is warranted to 120 mph when installed to manufacturer specification.
Freeze–thaw
A winter that hovers around freezing is harder on asphalt and wood than steady cold: water gets in, freezes, expands and thaws, over and over. Aluminum absorbs no water.
Ice dams
Ice dams come from heat escaping into the attic and from ventilation, not from the roof covering, and no roof prevents them on its own. Ice damming is a stated exclusion of the material warranty, so the installer should look at your attic too.
Salt air
Near the Sound, the bays and the ocean, salt rusts steel wherever its coating is cut or scratched. Aluminum has no steel to rust.
How do metal, asphalt and wood compare?
Published life expectancies are averages. Local weather, the building and its design, material quality and maintenance all move them, as the study below says itself.
| Roof | Life expectancy | Source | What to know |
|---|---|---|---|
| Asphalt shingles | About 20 years | NAHB / Bank of America study (2007) | The most common roof in the U.S. When it is done, it comes off or, where suitable, is roofed over once. |
| Wood shakes | About 30 years | NAHB / Bank of America study (2007) | Needs cleaning and re-treating, and splits and rots as it ages. Always torn off before a new roof. |
| Interlock® aluminum | Aluminum has been known to last over 100 years | A property of the metal, not a promise | What is promised is in the warranties: the Guardian Lifetime Limited Material Warranty and the 30-year Alunar® coating warranty. |
What is actually promised, in writing?
- Guardian Lifetime Limited Material Warranty, issued by Interlock Roofing: material and finish, for the original homeowner while they own the home. It transfers once; the second owner is covered to 50 years from substantial completion.
- 30-year Alunar® coating warranty on the finish.
- Wind resistance warranted to 120 mph when installed to manufacturer specification.
- Workmanship: the assigned installer's own written terms. Read them before you sign; there is no separate Interlock workmanship warranty.
- Exclusions to read: workmanship, and ice damming, among others. Hail damage is excluded except splitting, cracking and perforation from hailstones 1.5 inches or less.
Questions, answered
How long does a metal roof last?
It depends on the metal, the coating, the fasteners and the installation. Steel lasts about as long as its protective coating, because it rusts where the coating fails. Aluminum cannot rust, and aluminum has been known to last over 100 years. That is a property of the metal, not a promise; what is promised is in the written warranty.
How long do metal roofs last on Long Island?
Nor'easters, freeze–thaw, summer sun and salt air near the water are hard on roofing that absorbs water or relies on exposed screws. An aluminum roof with concealed fasteners, installed to manufacturer specification with good attic ventilation, avoids the usual failure points. Its material and finish are covered by the Guardian Lifetime Limited Material Warranty and the 30-year Alunar® coating warranty.
Does a metal roof last longer than asphalt shingles?
In published figures, yes. A 2007 study by the U.S. National Association of Home Builders and Bank of America put the life expectancy of asphalt shingles at about 20 years and wood shakes at about 30, noting that local weather, building and design, material quality and maintenance all affect it. Aluminum has been known to last over 100 years.
How long does a steel roof last?
A steel roof lasts about as long as its metallic coating and paint keep water off the steel; where the coating is scratched or cut, steel rusts. The Interlock® roof is aluminum, which cannot rust.
What does the Guardian Lifetime Limited Material Warranty cover?
Material and finish, for the original homeowner while they own the home. It is issued by Interlock Roofing and transfers once, and the second owner is covered to 50 years from substantial completion. Workmanship is excluded from it; the assigned installer gives their own workmanship terms. The finish has a 30-year Alunar® coating warranty. Read the full terms before you sign.
Will the color fade?
All exterior finishes change with years of sun. The Alunar® finish on Interlock® roofs carries a 30-year Alunar® coating warranty; the terms set out what is covered.
What maintenance does a metal roof need?
Keep gutters and valleys clear of leaves and needles, look the roof over after a major storm, and keep attic vents open. With concealed fasteners there are no exposed screws to re-tighten or re-seal.
Sources
- National Association of Home Builders / Bank of America Home Equity: Study of Life Expectancy of Home Components (February 2007)
- Guardian Lifetime Limited Material Warranty (full document, PDF)
- ICC-ES Evaluation Report ESR-1790, Interlock Roofing, reissued September 2025 (PDF)
- J.R. Davis, "Aluminum and Aluminum Alloys", Alloying: Understanding the Basics, ASM International (2001)
- Interlock Roofing: the aluminum roofing system (manufacturer)
- National Weather Service: nor'easters (winter weather safety)
- National Hurricane Center: U.S. mainland hurricane strikes by state, 1851–2004
Product specifications are the manufacturer's (Interlock Roofing). Laws, codes and statistics are as published by the source cited. Reviewed by Scott Plumptree, October 7, 2026.
Get a roof that should be your last one quoted.
Metal Roofing New York supplies the roof and assigns a certified Interlock installer for your part of Long Island, who visits, measures and gives you a written contract under their own Nassau or Suffolk County license. Nassau and Suffolk counties only.
