Five roofing metals cover almost every metal roof in the United States: steel, aluminum, copper, zinc and stainless steel. Steel is the workhorse and the budget pick, aluminum wins near the coast, and copper, zinc and stainless are the premium, lifetime materials. Here is how they compare, with a guide for each one.
Steel
Most metal roofs are steel, because it is strong, affordable and available in every profile and color. Residential standing seam is typically 24 or 26 gauge; exposed fastener agricultural panels are often 29 gauge. Bare steel rusts, so roofing steel is coated: Galvalume, a 55 percent aluminum-zinc alloy coating, is the standard base for painted roofing and resists rust longer than plain galvanized (zinc-only) steel in most settings. The paint on top matters as much as the coating underneath. Read Galvalume vs galvanized and gauge explained, or find companies that work in steel.
Aluminum
Aluminum does not rust, which makes it the usual choice within a mile or two of salt water, where steel warranties often do not apply. It is about a third the weight of steel, so panels are easy to handle, and it takes the same PVDF paint finishes. It is softer than steel and moves more with temperature, so installers use thicker sheet, commonly .032 inch for standing seam, and pay attention to clip spacing and oil canning. Read the aluminum guide or find aluminum roofing companies.
Copper
Copper is the roof that outlasts the building. It needs no paint, solders beautifully for flat-lock and flashing work, and weathers from bright metal to brown to the green patina people pay a premium for. The common roofing weight is 16 ounces per square foot. It is also the most expensive mainstream roofing metal, and runoff can stain masonry and other metals below it. Read the copper guide or find copper roofing companies.
Zinc
Zinc is common on European roofs and growing in the United States. It forms a matte blue-gray patina that protects the metal and gradually covers scratches, and it lasts 80 to 100 years or more. It is soft, forgiving to fold and well suited to standing seam, flat-lock and batten seam. The underside must stay dry and ventilated or be coated, because zinc corrodes from the back if condensation sits on it. Read the zinc guide or find zinc roofing companies.
Stainless steel
Stainless steel is the specialist’s metal: extremely durable, unaffected by salt air in the right grade, and available bright, matte or with a dulled terne-look finish. Type 304 is common inland and type 316 is the choice near the coast. It is hard to form and expensive, so it shows up on landmark buildings, coastal homes and places where nothing else will last. Read the stainless steel guide or find stainless steel roofing companies.
Side by side
Lifespans assume a well-installed roof over a solid deck; weights are approximate panel weights per square foot; cost tiers are relative, installed, and vary by region, pitch, complexity, finish and the time of year.
| Metal | Typical life | Weight | Cost tier | Near salt water | Weathering and patina |
|---|---|---|---|---|---|
| Painted Galvalume steel | 40 to 60 years | Roughly 1 to 1.5 lb per sq ft | Lowest | Fair; most warranties exclude salt-spray zones | Paint fades slowly; no patina |
| Aluminum | 50 years or more | Roughly 0.5 to 0.7 lb per sq ft | Medium | Excellent | Painted finishes fade slowly; bare metal dulls to gray |
| Copper | 100 years or more | Roughly 1 to 1.3 lb per sq ft | Highest | Very good; runoff can stain surfaces below | Brown within months, green over years to decades |
| Zinc | 80 to 100 years or more | Roughly 1 to 1.5 lb per sq ft | Highest | Good; needs a ventilated or coated underside | Matte blue-gray patina that covers scratches |
| Stainless steel | 60 to 100 years or more | Roughly 1 to 1.5 lb per sq ft | High to highest | Excellent in type 316 | Stays bright or matte; no patina |
The finish matters as much as the metal
On steel and aluminum, the paint system decides how the roof looks in 20 years. PVDF finishes (sold under the Kynar 500 and Hylar 5000 names) resist fading and chalking best and carry the longest finish warranties; SMP (silicone-modified polyester) costs less and is common on agricultural and budget panels. Ask every bidder which system is quoted and read PVDF vs SMP and warranties explained before you compare prices. Copper, zinc and stainless are usually left bare.
How to choose
- Most houses, most budgets: 24 or 26 gauge Galvalume steel with a PVDF finish.
- Within a mile or two of the ocean or a salt bay: aluminum, or stainless if the budget allows.
- A roof you never want to replace, and a budget to match: copper or zinc.
- Historic restoration: whatever the building had, usually copper, zinc, terne-look stainless or painted steel.
- Barns, shops and sheds: 26 or 29 gauge steel panels, Galvalume bare or painted.
Whatever you pick, the installer matters more than the metal. Get three written bids that name the metal, gauge or thickness, coating and finish, and read what a metal roof costs so the numbers make sense. The styles hub covers the shapes these metals come in.