The short answer: no, aluminum does not rust. Rust is iron oxide — and aluminum contains no iron. Instead, aluminum instantly forms a microscopically thin, self-healing oxide layer that seals the metal against salt air, humidity, and time. That single property is why Interlock builds every roof system in aluminum, and why coastal New England homes keep them for life.
Aluminum is tougher than you think
Aluminum is often thought of as the lightweight metal — what’s less understood is that it can also be some of the toughest material on earth. Pure aluminum is alloyed with elements like silicon, magnesium, and copper to create high-strength alloys used where strength and durability matter most. A few facts:
- The airframe of the F-16 fighter jet is about 80% aluminum.
- NASA chose a high-strength aluminum-lithium alloy for the Orion spacecraft.
- The U.S. Army uses crash-absorbent aluminum in the Humvee and Bradley Fighting Vehicle — chosen for weight, rust resistance, and reliability.
- Shark cages are built from aluminum because it won’t corrode in salt water.
- The strongest aluminum alloys exceed 72,000 psi — a 1.2-inch wire of that alloy could suspend a fully loaded tractor-trailer.
- The Wright brothers used aluminum for the engine crankcase of their first biplane in 1903, and Ford’s F-150 went all-aluminum-body in 2015, shedding 700 pounds. “Pound for pound, aluminum is stronger and tougher than steel,” said Ford’s then-CEO Alan Mulally.
Why this matters on a roof
- Salt air: aluminum’s oxide layer means no rust creep at cut edges or scratches — the failure points of coated steel. From Cape Cod to the Maine coast, that’s the decisive difference.
- Energy: properly coated aluminum roofs can reflect up to 95% of solar energy, dramatically improving cooling efficiency — a key component of LEED-certified green building.
- Weight: light enough to install over most existing roofs without structural work, while making the panels thicker where it counts for dent resistance.
Infinitely recyclable
Aluminum is 100% recyclable and retains its properties indefinitely — nearly 75% of all aluminum ever produced is still in use today. Recycling it takes about 8% of the energy of primary production, and recycling one ton saves the energy equivalent of 21 barrels of oil. Interlock roofing is made from ~95% recycled aluminum — and unlike an asphalt roof, it will never see a landfill.
Questions about aluminum vs. steel for your home? Read the full comparison or request a free estimate.
