Florida · Steel vs aluminum
Steel vs aluminum roofing
A steel roof is protected from rust by its zinc or aluminum-zinc coating and paint, and lasts as long as they do. An aluminum roof has no steel to rust: its oxide film protects it, and it weighs about a third as much. Steel usually costs less up front; aluminum is the longer-lived choice.
Reviewed by Scott Plumptree, Director of Marketing, The Interlock Group · Updated October 7, 2026
Steel
Protected by its coating
Galvanized (zinc) or Galvalume (aluminum-zinc).
Aluminum
Protected by the metal itself
An oxide film blocks further oxidation.
Weight
Aluminum ≈ one-third of steel
By density, ASM International.
How do steel and aluminum roofing compare?
Steel is protected by a coating; aluminum protects itself. That one difference drives most of the rest of the table.
| Steel roofing | Aluminum roofing | |
|---|---|---|
| What keeps it from corroding | A metallic coating, zinc (galvanized) or aluminum-zinc (Galvalume), under the paint | The aluminum itself: its oxide film blocks further oxidation |
| If the finish is scratched or cut | The steel is protected only as long as the coating around it lasts; galvanized cut edges are bare steel once the zinc nearby is used up | Bare aluminum forms the same oxide film; there is no steel to rust |
| Weight | Heavier | About one-third the density of steel |
| Dents | Thicker steel resists denting better than thin aluminum | Very large hail or foot traffic can leave a cosmetic mark; read how a warranty treats cosmetic marks |
| Up-front price | Usually lower | Usually higher |
| Things to avoid | Galvalume corrodes quickly in contact with wet mortar or concrete, and should not take run-off from copper | Keep it out of direct contact with dissimilar metals; flashings are matched to the system |
| Typical buyer | Lowest up-front cost, inland site | Longest-lived option; salt air, or shade that keeps a roof damp |
Steel: ArcelorMittal Dofasco (Galvalume product information) and Gibraltar Building Products. Aluminum: ASM International. References at the end of the page.
Which is better for a roof in Florida?
Near the water, aluminum. Salt air on both coasts attacks steel wherever its coating is cut or scratched, and aluminum has no steel to rust. Inland, a good steel roof is a sound roof; the question there is how long you'll own the house and how much a future re-roof is worth avoiding. Either way, ask for the Florida Product Approval number of the exact product you're quoted.
Why is most metal roofing sold steel?
Steel coil is widely available and costs less, so most metal roofing sold in the U.S. is steel: painted steel tile, steel shingles and steel panels. A good steel roof, well installed, is a sound roof. Its life depends on its metallic coating and paint, which is why steel warranties are written in years.
The Interlock® roof is aluminum because that takes the coating question off the table: a scratch, a cut edge or a fastener hole has no steel behind it to rust. Metal Roofing Florida supplies the aluminum roof in Florida, and a certified Interlock installer is assigned to put it on.
Which questions settle it for your house?
- How long do you plan to own the home? The longer you stay, the more a roof you never replace is worth.
- Is the house near salt water, or under trees that keep the roof damp?
- Do you want a slate, cedar or tile look, or plain panels? Profiles differ more than metals.
- Who is the warrantor, the manufacturer or the contractor, and what does the material warranty cover after year ten?
- Are the fasteners concealed or screwed through the face?
Questions, answered
Is steel or aluminum better for a roof in Florida?
Both make good roofs. Steel costs less up front and depends on its zinc or aluminum-zinc coating to keep from rusting. Aluminum cannot rust and is about a third the weight. Near salt water on either coast, aluminum is the longer-lived choice.
Does a steel roof rust?
Steel itself rusts; a steel roof is protected by its metallic coating and paint. Where the coating is cut, scratched or used up, as at galvanized cut edges over time, rust can start.
Does an aluminum roof rust?
No. Aluminum forms an oxide film that blocks further oxidation, and there is no steel in an aluminum roof to rust.
Is aluminum roofing more expensive than steel?
Usually, yes, up front. The certified installer assigned to your project gives you a written proposal for the Interlock® aluminum roof, so you can compare it with a steel quote line by line.
Is steel roofing stronger than aluminum?
Steel is stronger and stiffer for the same thickness, which is why it resists denting better. Aluminum is lighter. On a roof deck, both carry load through the structure underneath; panel strength matters most for dents.
Where do I get an aluminum roof instead of steel in Florida?
Request a quote on this site or call the toll-free line. Metal Roofing Florida assigns a certified Interlock installer to your project.
Sources
- ArcelorMittal Dofasco: Galvalume™ steel sheet, product information
- Gibraltar Building Products: why are the edges of my painted galvanized roof rusting?
- J.R. Davis, "Aluminum and Aluminum Alloys", Alloying: Understanding the Basics, ASM International (2001)
- Interlock Roofing: aluminum shingles, technical specifications
- National Hurricane Center: U.S. mainland hurricane strikes by state, 1851–2004
- Florida Product Approval NEMO P.E. Evaluated FL7263-R7, P.E. evaluation report, 8th Edition (2023) Florida Building Code, non-HVHZ (PDF)
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.
Compare an aluminum proposal with your steel quote.
Metal Roofing Florida supplies the roof and assigns a certified Interlock installer for your part of Florida, who visits, measures and gives you a written proposal under their own Florida license. Miami-Dade and Broward counties are not served.
