North Carolina · Roof lifespan guide
How long does a metal roof last in North Carolina?
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 does not rust, and aluminum has been known to last over 100 years. That is a property of the metal, not a promise; what Metal Roof NC and the manufacturer put in writing is in the warranties, set out below.
The metal
Aluminum has been known to last over 100 years
Aluminum does not rust. A property of the metal, not a promise.
The material
Guardian Lifetime Limited Material Warranty
Material and finish, for the original purchaser while they own the home. Transferable once.
The finish
Alunar® coating warranted 30 years
On the paint finish that carries the color.
What decides how long a metal roof lasts?
Four things decide how long a metal roof lasts: the metal, the coating, the fasteners and the installation. "Metal roof" covers very different products.
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 does not 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 humidity. Interlock® roofs use an Alunar® 70% PVDF finish (AAMA 2605), and the Alunar® coating is warranted 30 years, separate from the material warranty.
The fasteners
Exposed screws through the weather surface rely on rubber washers that dry out and crack in years of summer sun. 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, the 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.
What does North Carolina weather do to a roof?
North Carolina weather ages a roof through heat and humidity every summer, tropical storms from the coast inland, salt air near the ocean, and hail and ice in the Piedmont. Each finds a different weak point.
Heat and humidity
Long, hot, humid summers age asphalt fastest: granules loosen, the mat dries out, and shaded roofs grow dark algae streaks and moss. Aluminum absorbs no water and has no granules to lose; the finish carries the color, and its 30-year coating warranty is what to read.
Hurricanes and tropical storms
Florence came ashore near Wrightsville Beach in September 2018 and dropped more than 30 inches of rain in parts of the state (NWS Wilmington); Matthew in 2016 brought coastal gusts above 70 mph (NWS Raleigh), and Helene in 2024 showed that inland western North Carolina is not immune (NWS Greenville-Spartanburg). Interlocked panels leave no tab edge for wind to lift. No roof is immune to hurricane damage.
Salt air on the coast
From Wilmington to Morehead City, New Bern and Beaufort, salt spray rusts steel wherever its coating is cut or scratched. Aluminum has no steel to rust; it is corrosion-resistant, and flashings and fasteners must be compatible metals.
Piedmont hail and ice
May has seen the most hail in North Carolina, and the western Piedmont is the iciest part of the Southeast (State Climate Office of NC). Aluminum absorbs no water for ice to work on; large hail can leave cosmetic dents.
How does metal compare with asphalt and cedar?
Metal outlasts both on published figures, but 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 | Basis | What to know |
|---|---|---|---|
| Asphalt shingles | About 20 years | NAHB / Bank of America study (2007) | The most common roof in North Carolina. When it is done, it comes off or, if an inspection finds it 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 in humid summers. 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 Alunar® coating warranty (30 years). |
Asphalt and wood shake figures: National Association of Home Builders and Bank of America Home Equity, Study of Life Expectancy of Home Components, February 2007 (a US study). Full reference at the end of this page.
What do the warranties actually promise?
The warranties promise material, finish and workmanship coverage for set terms, which is a different thing from how long aluminum can last. Here is what is in writing on an Interlock® roof installed in North Carolina by Metal Roof NC.
- Guardian Lifetime Limited Material Warranty, from the manufacturer, Interlock Roofing: material and finish, for the original purchaser while they own the home, transferable once. The second owner is covered to 50 years from substantial completion. Workmanship is excluded. Full warranty (PDF)
- Alunar® coating warranted 30 years.
- Metal Roof NC 5-Year Labor Warranty, covering workmanship for five years. Warranties explained
- Wind resistance warranted to 120 mph when installed to manufacturer specification.
Should I replace asphalt with metal now?
If you plan to keep the house, replacing worn asphalt with metal now usually means it is the last roof you buy. Cedar shakes, concrete tile and natural slate always come off first; a single layer of asphalt may be roofed over only if an inspection finds it suitable and local code allows it. The Interlock® profiles (Slate, Cedar Shingle, Shake, Mediterranean Tile and Standing Seam) weigh roughly 0.4 to 0.7 lb per square foot and are made in North America by Interlock Roofing.
Metal Roof NC's rule of thumb is that an Interlock aluminum roof typically costs about 2.5 to 3 times a traditional asphalt-shingle roof. Prices vary job to job with roof size, pitch, tear-off and other conditions, and an on-site estimate is required for an accurate price. See metal roof cost, aluminum roofing in NC and hurricane-resistant roofing.
Metal roof lifespan: 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 does not 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 in North Carolina?
North Carolina's heat, humidity, tropical storms, coastal salt air and Piedmont hail and ice 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, and its material and finish are covered by the Guardian Lifetime Limited Material Warranty.
Does a metal roof last longer than asphalt shingles?
In published figures, yes. A 2007 study by the National Association of Home Builders and Bank of America put asphalt shingles at about 20 years and wood shakes at about 30, noting that local weather, 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, and coastal salt air speeds that up. Metal Roof NC installs aluminum, which does not rust.
What does the Guardian Lifetime Limited Material Warranty cover?
It covers material and finish for the original purchaser while they own the home, and it transfers once; the second owner is covered to 50 years from substantial completion. Workmanship is excluded from it; the installation is covered by the Metal Roof NC 5-Year Labor Warranty. The Alunar® coating is warranted 30 years. Read the full terms before you sign.
Will the color fade in North Carolina sun?
All exterior finishes change with years of sun. The Alunar® 70% PVDF finish on Interlock® roofs is warranted 30 years; the terms set out what is covered.
What maintenance does a metal roof need?
Keep gutters and valleys clear of pine needles and leaves, look the roof over after a tropical storm or ice 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)
- National Weather Service Wilmington, NC: Hurricane Florence (2018)
- National Weather Service Raleigh: Hurricane Matthew, October 8, 2016 event summary (PDF)
- National Weather Service Greenville-Spartanburg: Hurricane Helene (2024) post-tropical cyclone report (PDF)
- State Climate Office of North Carolina: Hail Hath No Fury Like a Springtime Storm (2016)
- State Climate Office of North Carolina: wintry precipitation and freezing rain
- Guardian Lifetime Limited Material Warranty (full document, PDF)
- ICC-ES Evaluation Report ESR-1790, Interlock Roofing (PDF)
Page reviewed October 17, 2026.
Related
- Interlock roofing in NC
- Hurricane-resistant roofing
- Roof replacement
- Hurricane-resistant roofing
- Cedar shake roof replacement
- Condo & townhouse roofing
- Fire-resistant roofing
- Metal roof cost
Where we install in North Carolina
Metal Roof NC installs Interlock® aluminum roofs across the Triangle, the Charlotte area, the Triad and Piedmont, and the coast. See every service area.
Charlotte area
Triad and Piedmont
Get an aluminum roof estimated.
A project-specific estimate before work begins. Metal Roof NC, an authorized Interlock aluminum roofing dealer · 5301 Hillsborough St, Raleigh, NC 27606