Metal roofs are made of one of five base metals: steel, aluminum, copper, zinc, or stainless steel. Steel is the most common by far. Every metal roof starts as flat sheet metal rolled off a coil, gets a corrosion-fighting coating (either a metallic layer or a natural oxide), and then a baked-on paint finish before it is roll-formed into panels, shingles, or tiles. The metal underneath is what determines cost, weight, and lifespan.
What metals are used in metal roofing?
Five metals cover nearly all residential and commercial metal roofing: steel, aluminum, copper, zinc, and stainless steel. Steel and aluminum account for the vast majority of installed panels because they cost far less than the specialty metals. Copper, zinc, and stainless steel are premium options chosen for architecture, coastal corrosion resistance, or century-long service life.
| Metal | What it actually is | Typical thickness | Corrosion protection | Approx. installed cost (2026) | Service life |
|---|---|---|---|---|---|
| Steel | Iron-carbon alloy sheet | 29 to 24 gauge | Zinc or aluminum-zinc metallic coating plus paint | $4 to $12 / sq ft | 40 to 60 years |
| Aluminum | Aluminum-manganese alloy (3000 series) | 0.032 to 0.040 in | Natural oxide layer plus paint | $6 to $16 / sq ft | 50-plus years |
| Copper | Roughly 99.9% pure copper | 16 to 20 oz / sq ft | Self-forming green patina | $18 to $40 / sq ft | 70 to 100-plus years |
| Zinc | ~99% zinc with titanium and copper | 0.7 to 0.8 mm | Self-healing patina | $15 to $35 / sq ft | 60 to 100 years |
| Stainless steel | Iron alloyed with 10.5%-plus chromium (304 or 316) | 26 to 24 gauge | Chromium oxide layer | $15 to $30 / sq ft | 60 to 100 years |
Cost ranges are approximate installed figures and vary by region, panel profile, and roof complexity. Thicker gauge (a lower gauge number) means more metal and a higher price, which is why a 24 gauge standing seam roof costs more than a 29 gauge exposed-fastener panel of the same metal.
What is steel roofing made of?
Steel roofing is an iron-carbon alloy sheet with a metallic anti-corrosion coating bonded to both faces, then painted. Bare steel rusts, so the coating is what lets it survive on a roof. Two coating systems dominate: galvanized (pure zinc) and Galvalume (an aluminum-zinc blend). The steel core is identical; the coating chemistry is the difference that matters.
- Galvanized steel: coated with 100% zinc. The industry benchmark is G90, which carries 0.90 oz of zinc per square foot across both sides. Zinc protects sacrificially, corroding before the steel does, especially at cut edges.
- Galvalume (also sold as Zincalume): coated with an alloy that is about 55% aluminum, 43.4% zinc, and 1.6% silicon by weight. The common AZ50 and AZ55 grades resist flat-surface corrosion better than galvanized and last longer in most climates, though it is weaker at cut edges near salt water.
For a full side-by-side on the two coatings and how gauge affects price, see our breakdown of galvanized versus Galvalume steel and gauge.
What are aluminum, copper, zinc, and stainless steel roofs made of?
The four non-steel metals each resist corrosion on their own, so they skip the metallic coating that steel requires. Their composition explains why they cost more and last longer than steel.
- Aluminum is an aluminum-manganese alloy, usually 3003 or 3105 in the 3000 series. It forms a thin oxide layer the moment it meets air, so it never rusts and needs no zinc coating, only paint for color. That makes it the default choice within a few miles of salt water.
- Copper is close to 99.9% pure and sold by weight, commonly 16 oz or 20 oz per square foot. It develops a green patina over 10 to 30 years that seals the surface and can carry the roof past a century.
- Zinc roofing is roughly 99% zinc with small additions of titanium and copper for strength, sold by brands such as VMZINC and RHEINZINK. Its patina is self-healing, closing over scratches over time.
- Stainless steel is iron alloyed with at least 10.5% chromium, typically type 304 or the more corrosion-resistant 316. The chromium forms a passive oxide film that reseals if scratched. Terne-coated stainless adds a tin-based matte finish.
Each of these has its own cost and lifespan profile. Our guides to aluminum roofing cover where the lighter metal earns its premium.
What coatings and paint finishes go on a metal roof?
A painted steel roof is built in layers: steel core, metallic coating, pretreatment, primer, and a colored topcoat, with a thin backer on the underside. The paint does two jobs, adding color and blocking UV. The paint chemistry, not the color, decides how long the finish holds up.
| Paint system | What it is | Fade and chalk resistance | Typical finish warranty | Best for |
|---|---|---|---|---|
| SMP | Silicone-modified polyester | Moderate | 25 to 30 years | Budget panels, agricultural and outbuildings |
| PVDF (Kynar 500 / Hylar 5000) | Fluoropolymer resin | Highest available | 30 to 40 years | Homes and commercial where color must hold |
PVDF, marketed under the Kynar 500 and Hylar 5000 names, is the premium finish and resists fading and chalking better than SMP. On bare copper, zinc, and stainless roofs, there is often no paint at all, since the metal is left to patina naturally.
Are metal roofs actually made of tin?
Almost no modern metal roof is made of tin. The phrase tin roof is a holdover from the 1800s and early 1900s, when roofs were made of terne, a steel or iron sheet coated in a tin-lead alloy. Today a so-called tin roof is nearly always galvanized or Galvalume steel. The name stuck; the material changed.
True tin was never structural on its own. It was a thin protective coating over a stronger base metal, much like zinc coats galvanized steel now. If someone quotes you a tin roof, ask what the panels actually are, because it is almost certainly coated steel or aluminum.
How is metal roofing made?
Metal roofing is manufactured from coil, not cast or cut from thick plate. The mill starts with a giant rolled coil of steel or aluminum and finishes it before it ever reaches a roll former. The process is why panels arrive pre-colored and consistent.
- Coil production. Steel or aluminum is cold-rolled into thin sheet and wound into coils, each weighing several tons.
- Metallic coating. Steel coil passes through a molten zinc or aluminum-zinc bath to become galvanized or Galvalume. Aluminum, copper, and zinc skip this step.
- Paint line. The coil is cleaned, pretreated, primed, and coated with a baked-on SMP or PVDF topcoat, then oven-cured.
- Roll forming. The finished coil feeds through a roll former that bends it into the panel profile, whether standing seam, exposed-fastener, or a stamped metal shingle or tile.
- Cut to length. Panels are sheared to the exact roof dimension, often on site for standing seam, which is why runs can span an entire slope with no horizontal seam.
For the full range of shapes this process produces, see our guide to metal roofing types, panels, and profiles.
Which metal roofing material is most common?
Steel is the most common metal roofing material, and metal as a whole runs a distant second to asphalt shingles on U.S. homes. Steel wins on cost, so galvanized and Galvalume panels make up the bulk of what gets installed, while aluminum leads in coastal zones and the specialty metals stay niche.
The exact split between roofing materials shifts by region and year. Our roofing material market share report breaks down what U.S. roofs are actually made of using national housing data, and it sits inside our broader roofing basics learning hub if you are comparing metal against shingles, tile, or slate.
Frequently asked questions
What are metal roofs most commonly made of?
Most metal roofs are made of steel, coated with either zinc (galvanized) or an aluminum-zinc alloy (Galvalume) to stop rust, then painted. Steel dominates because it costs the least. Aluminum is the second most common, favored near salt water, while copper, zinc, and stainless steel are premium metals used for architecture or very long service life.
Are metal roofs made of steel or aluminum?
Both, though steel is far more common. Steel is cheaper and stronger but needs a zinc or aluminum-zinc coating to resist rust. Aluminum costs more, weighs less, and never rusts because it forms its own oxide layer, which makes it the standard choice within a few miles of the coast where salt attacks steel.
What is Galvalume made of?
Galvalume is steel sheet coated with an alloy that is roughly 55% aluminum, 43.4% zinc, and 1.6% silicon by weight. The aluminum gives long flat-surface corrosion resistance and the zinc protects cut edges. It is sold as Galvalume or Zincalume in grades such as AZ50 and AZ55, the number noting coating weight.
Are metal roofs actually made of tin?
No. The term tin roof dates to the era of terne, a steel sheet coated in a tin-lead alloy. Modern panels called tin roofs are almost always galvanized or Galvalume steel, or sometimes aluminum. Pure tin was never a structural roofing metal on its own, only a thin protective coating over a stronger base.
Do metal roofs rust?
Bare steel rusts, which is why roofing steel is coated in zinc or aluminum-zinc and painted. Aluminum, copper, zinc, and stainless steel do not rust, because each forms a protective oxide or patina layer on its own. A properly coated steel roof can go 40 to 60 years before corrosion becomes a concern, longer in dry climates.
What is the best metal for a roof?
It depends on budget and climate. Coated steel offers the best value for most homes. Aluminum is best near salt water. Copper and zinc last a century and suit high-end architecture. Stainless steel handles harsh industrial or coastal exposure. There is no single best metal, only the best match for your site and price range.
Reviewed by The Roofing Brief Team. Last reviewed July 2026.