Metal siding is a family of products, not one material: rolled steel, aluminum, zinc, and copper panels, formed into profiles from a $2-per-sq-ft corrugated sheet to a hand-fabricated copper wall. It is noncombustible, shrugs off hail, and needs almost no upkeep. Installed cost runs $7 to $15 per sq ft for painted steel, $8 to $16 for aluminum, and $25 and up for zinc and copper.
The catch: “metal siding” is not a specification. A 29-gauge snap-lock panel from a home center and a 24-gauge standing seam system share a family name and almost nothing else. Gauge, profile, coating, and fasteners decide whether you get 50 years or a wavy, chalked wall in ten.
This guide covers the four metals, the five profiles, how gauge and finish drive durability, how metal handles fire, wind, hail, and salt, and where it fails.
Steel, Aluminum, Zinc, and Copper: What Each Metal Is For
Steel is the volume product and what most homeowners buy. It is stiff and cheap, but ferrous: scratch the coating at a cut edge or fastener head and it rusts. Coated steel over a drainage plane is a 40-to-60-year wall.
Aluminum weighs a third as much, never rusts, and skins over with its own protective oxide, making it the default in salt air. It is softer, so it dents from a stray ball or a mower stone, and it must be isolated from treated lumber and copper. We cover it in depth in our aluminum siding guide.
Zinc is a European architectural metal with a modest US following. Sold by thickness — typically 0.8 mm — it self-heals minor scratches and runs 60 to 100 years. It is matte and expensive, and it weathers to a gray some HOAs read as unfinished.
Copper is the landmark metal. At 16 to 20 oz per sq ft, it darkens from bright to brown to the familiar green patina over 15 to 30 years. Expect 100-plus years and a bill to match, usually on historic restorations and architect-designed homes.
| Metal | Thickness | Installed cost / sq ft | Service life | Best used for |
|---|---|---|---|---|
| Steel | 24–29 ga | $7–$15 | 40–60 yrs | Hail belt, wildfire zones, mainstream re-sides |
| Aluminum | 0.019–0.032 in. | $8–$16 | 30–50 yrs | Coastal and salt-air homes |
| Zinc | 0.8 mm | $25–$45 | 60–100 yrs | High-end contemporary work |
| Copper | 16–20 oz | $35–$60+ | 100+ yrs | Historic and landmark buildings |
For most US homes the real choice is steel or aluminum: steel on price and dent resistance, aluminum on salt air and weight. Zinc and copper are specification choices, not budget ones.
Profiles and Fastener Strategy
The profile decides the look, how the wall drains, and whether fasteners show. Standing seam is the premium form: concealed clips, no exposed fasteners, pans 12 to 24 inches wide. Because the clips let the panel float, it handles movement and wind uplift best.
Corrugated and ribbed panels fasten through the ribs with exposed screws and gasketed washers. They are cheap, fast, and read as agricultural — barns, shops, and the modern farmhouse look.
Horizontal lap panels copy clapboard or board-and-batten and hide fasteners behind a nailing hem, which is why they clear architectural review more often than corrugated. Snap-lock vertical panels interlock at the seam with no clips or screws, making them the most DIY-friendly form.
Insulated foam-core panels bond rigid foam between two steel skins, adding roughly R-5 to R-8 and killing most of the drumming noise. They are heavier and thicker at the trim, but on a wall behind a bedroom they change how rain sounds.
Gauge, Oil-Canning, and Hail
Gauge is a thickness callout, and lower numbers mean thicker metal. 29 gauge is about 0.014 in., 26 gauge is 0.019 in., and 24 gauge is 0.025 in. — nearly double the steel of 29. Anything thinner than 26 gauge belongs on a shed.
Thin panels oil-can. When the sun heats a panel it expands; pinned rigidly, the metal has nowhere to go and ripples between fasteners. It is cosmetic but permanent, and worst on dark colors in afternoon sun.
Thin panels also dent: a 29-gauge wall in the Texas-to-Kansas hail belt can look like a golf ball after one bad spring. Hail performance is rated under UL 2218, and Class 3 or Class 4 is the target — but the rating belongs to the tested assembly, not the panel alone: substrate and clip spacing matter as much as thickness.
Aluminum breaks the gauge convention: it is specified in inches, usually 0.019 to 0.032, because alloy and temper matter as much as thickness.
Finishes: SMP vs. PVDF, and the Substrate Underneath
Two coil coatings cover nearly all residential metal. SMP, silicone-modified polyester, is the standard: affordable, widely colored, and warrantied against fade and chalk for roughly 20 to 40 years. PVDF, sold as Kynar 500 or Hylar 5000, is a fluoropolymer with more resin and better UV stability, usually warranted 30 to 40 years.
PVDF costs more per square foot, and in Arizona, New Mexico, and coastal Florida it is the difference between a wall that holds its color and one that chalks out in a decade. Resin content is the tell: 70% PVDF is the architectural standard; 35% is not the same product.
Ask what the steel is coated with before it is painted. Galvalume — an aluminum-zinc alloy — and zinc-aluminum substrates resist cut-edge corrosion far better than plain galvanized, which is what lets a scratched panel go years without rust creeping along the cut.
Field note: If a bid says “26 gauge” without naming the substrate, the resin system, or the film thickness, assume commercial-quality steel with a thin SMP finish. That is a fine panel for a shed. It is not what you want on a house you plan to keep.
Fire, Wind, Hail, Salt, and Thermal Movement
Metal is noncombustible, its biggest structural selling point. In California’s wildland-urban interface and the fire-prone stretches of Colorado and Texas, steel and aluminum cladding are among the few finishes that satisfy ignition-resistant construction requirements.
Wind uplift depends on the assembly, not the alloy. A standing seam wall with concealed clips and tested clip spacing can carry very high ratings; a 29-gauge lap panel nailed every 16 inches will lift at the corners first. Ask for the tested uplift rating in writing.
Salt air attacks cut edges and fastener heads first, so coastal jobs need aluminum or stainless fasteners — never electroplated screws. Anywhere steel touches copper, treated lumber, or a dissimilar metal, galvanic corrosion starts quietly and shows up as a rust streak two years later.
Metal moves, and that is the detail installers get wrong. A 10 ft panel can grow and shrink by roughly 1/8 in. across a 100-degree swing. Fasteners belong in slotted or oversized holes with gasketed washers so the panel can slide; pin it tight and it oil-cans, then shears its screws.
Cost, Noise, and Where Metal Is the Wrong Choice
Material runs roughly $2 to $5 per sq ft for painted steel, $4 to $8 for aluminum, and $8 to $20 or more for zinc and copper. Installed, budget $7 to $15 per sq ft for steel and $8 to $16 for aluminum. Labor is lower than fiber cement siding: the panels are light and cover a lot of wall in a day. Trim — corners, rake caps, closures, custom brake work — is fabricated per job and can double the line.
On an open stud wall with no sheathing, rain and hail on metal are loud enough to wake you. Over solid sheathing with a drainage mat the difference is modest, and foam-core panels are quieter still. If the wall backs a bedroom, insulate it.
Metal is also the wrong fight in some places. Historic districts often prohibit it on a contributing facade, and many HOAs restrict profiles, colors, or ban it outright. On a 1920s colonial or a Craftsman bungalow, a standing seam wall fights the architecture, and corrugated reads as a barn. If lowest cost is the goal, vinyl siding still wins, though it loses on fire, hail, and lifespan.
Metal sheds water so cleanly that it sends more debris to the gutter, so under a tall canopy price a gutter leaf guard with the re-side.
Frequently Asked Questions
How long does metal siding last?
Expect 40 to 60 years for painted steel and 30 to 50 for aluminum, assuming the finish holds; zinc and copper run longer. The metal almost always outlives its paint, which is why the coating and substrate matter more than gauge.
Is metal siding loud in the rain?
On an open stud wall, yes — noticeably. Over solid sheathing with a drainage mat the difference is modest, and foam-core panels add R-5 to R-8 while quieting the drumming.
What gauge should I buy?
24 gauge for anything you want to keep, 26 gauge for a simple re-side on a protected site, and 29 gauge only for shops and sheds. Aluminum is specified in inches instead — 0.032 in. behaves like 24-gauge steel.
Can metal siding go over existing siding?
Sometimes. If the existing wall is flat and sound, most codes allow a new drainage plane and metal over it, saving tear-off and disposal. If the old siding is thick cedar shake or the barrier has failed, tear it off.
The Bottom Line
Metal is a better answer than it was twenty years ago, but it is a specification, not a category. For the hail belt, a wildfire zone, or a modern, farmhouse, or industrial design, buy 24-gauge steel with a Galvalume substrate, a 70% PVDF finish, concealed clips, and stainless fasteners. In salt air, switch to aluminum. In a historic district, or under an HOA that bans metal, do not force it. Get three local bids and put the fastener schedule in writing.
About the author
Daniel Whitfield writes about home exteriors, decor, and seasonal projects for Curb & Canvas. He researches siding, trim, gutter, and home-decor systems using manufacturer specifications, contractor pricing across US markets, and residential building-code requirements, then translates the trade-offs into plain language for homeowners. Read more about our editorial approach.
