• What is metal siding
• Aluminum vs steel
• Profiles & coatings
• Pros & cons
• Cost guide
• Installation process
• Maintenance
• Lifespan
• Vs other materials
• Repair vs replace
• Choosing an installer
• FAQ

What Is Metal Siding?

Metal siding is exterior cladding formed from coated aluminum or steel panels, engineered to shed water, resist fire, and hold up to decades of weather exposure with minimal upkeep. It’s grown well beyond its industrial and agricultural roots into a mainstream residential option, particularly for modern, farmhouse, and industrial-style architecture where clean panel lines and standing-seam profiles are part of the design intent rather than an afterthought.

Aluminum and steel are the two metals that make up the overwhelming majority of residential metal siding, and the choice between them is really a choice between two different failure modes: aluminum won’t rust but dents more easily, while steel resists denting far better but can rust if its protective coating is breached. Everything else in this guide — cost, install method, maintenance — flows from that core tradeoff.

Aluminum vs Steel Siding

Aluminum siding

Aluminum is naturally corrosion-resistant because it forms a stable oxide layer on its surface, which means it won’t rust even if the paint finish is scratched down to bare metal — a meaningful advantage in coastal and high-humidity environments where salt air accelerates corrosion on other metals. It’s also lighter and easier to work with on-site, and it’s the more common choice for retrofit applications over existing siding. Its main weakness is softness: aluminum dents more readily than steel under hail impact or accidental contact, and once a panel is dented it typically can’t be reshaped back to flat.

Steel siding

Steel is significantly stronger and more dent-resistant than aluminum, which makes it the preferred choice in hail-prone regions and for homeowners who want a panel that holds its shape under impact. Residential steel siding is virtually always coated — either galvanized (zinc) or Galvalume (zinc-aluminum alloy) as a base rust-inhibiting layer, finished with a baked-on paint system — because uncoated steel will rust. As long as that coating stays intact, steel siding is extremely durable; if it’s ever cut, scratched through to bare metal, or has fasteners driven improperly, rust can start at that exposed point and spread if left untreated.

Metal Siding Profiles and Coatings

• Standing seam — vertical panels with raised, interlocking seams and concealed fasteners, giving the cleanest, most modern look and the fewest points where water can find a fastener penetration.
• Corrugated and ribbed panels — wavy or trapezoidal profiles common on barns, sheds, and industrial-style homes, generally the most affordable metal siding profile.
• Board and batten metal panels — flat panels with raised battens covering the seams, built to mimic the board-and-batten wood look in metal.
• PVDF (Kynar) coatings — a premium baked-on paint finish with the best long-term color retention and chalking resistance, typically carrying the longest finish warranties.
• SMP coatings — a more affordable baked-on finish that performs well but generally fades and chalks faster than PVDF over the same time period.

Metal Siding Pros and Cons

Metal Siding Cost Guide

Metal siding’s cost is driven primarily by metal choice, gauge, and coating quality:

• Aluminum vs steel — steel generally costs somewhat less than aluminum per square foot for comparable panel styles, though pricing shifts with commodity metal markets for both.
• Gauge (thickness) — thicker-gauge panels resist denting and oil-canning better and cost more than thinner, more economical gauges.
• Coating system — PVDF (Kynar) finishes cost more upfront than SMP coatings but hold their color and resist chalking significantly longer.
• Profile — standing seam with concealed fasteners generally costs more in labor than simple corrugated or ribbed panel installations.
• Tear-off and disposal — as with any full replacement project, removing old siding to inspect the wall assembly underneath adds labor cost.

Metal Siding Installation Process

A correct installation of aluminum or steel siding depends on allowing the panels to move as they expand and contract with temperature:

1. Sheathing inspection and weather-resistant barrier. Old siding is removed and the sheathing is checked for rot or moisture damage, then a weather-resistant barrier is installed with correctly lapped seams.
2. Furring strips or a rainscreen gap. A rainscreen installation — furring strips or a purpose-built drainage mat behind the panels — creates a ventilated gap that lets incidental moisture drain and dry, and also gives panels a flat, consistent plane to fasten to.
3. Starter strip and corner trim. Starter strips at the base and trim at corners and openings establish straight, square reference lines before the field panels go up.
4. Panel fastening with slotted holes. Panels are fastened through slotted nail holes rather than driven tight, allowing the metal to expand and contract with temperature without buckling; over-driving fasteners is one of the most common installation mistakes.
5. Flashing at penetrations. Windows, doors, and any wall penetrations get properly integrated flashing so water is directed out and away rather than behind the panels.
6. Sealing cut edges. Any factory coating cut through on-site — particularly on steel panels — is touched up or sealed to prevent an exposed edge from becoming a rust starting point.

Fastening steel and aluminum panels correctly — with slotted holes and without over-driving fasteners — is the detail that prevents the buckling, oil-canning, and noise issues that plague poorly installed metal siding, since a panel fastened rigid at every point has nowhere to go as it naturally expands and contracts through the seasons.

Metal Siding Maintenance

• Rinse periodically with a garden hose to remove dirt, salt spray, or pollen buildup that can dull the finish over time.
• Inspect steel panels for coating breaches — scratches, chips, or fastener corrosion — and touch up exposed spots promptly before rust can spread.
• Check for dents after hail or storm events, particularly on aluminum panels, and address them before moisture can pool in a deformed area.
• Keep fasteners snug but not over-tightened so panels retain the ability to move slightly with temperature changes.
• Re-seal flashing and trim joints as caulking ages, especially around windows, doors, and corner trim.

Metal Siding Lifespan

Both aluminum and coated steel siding commonly last 40 to 70 years, among the longest lifespans of any siding material, with the coating system driving most of the variation. A PVDF-finished panel that’s properly installed and occasionally rinsed can outlast the mortgage on the house it’s protecting; a lower-grade coating in a harsh coastal or industrial environment will chalk, fade, and — on steel specifically — become vulnerable to rust well before that. Aluminum’s failure mode tends to be cosmetic dent damage accumulating over time, while steel’s is localized rust starting at a coating breach and spreading if untreated — both are reasons regular visual inspection matters even though metal siding otherwise asks very little of the homeowner.

Metal Siding vs Other Materials

Metal Siding: Repair vs Replace

• Choose repair when damage is limited to a small number of dented or rust-spotted panels and the surrounding wall assembly is dry and sound.
• Choose residing when existing siding is flat and structurally sound — metal panels are a common overlay choice specifically because their furring-strip installation naturally creates a ventilated gap over the old surface.
• Choose full replacement when rust has spread across multiple panels, when widespread hail damage has left the wall visibly wavy or oil-canned, or when a fastening or expansion-gap error has caused systemic buckling across the wall.

How to Choose a Metal Siding Installer

Ask specifically whether the contractor installs a furring strip or rainscreen gap behind the panels, what gauge and coating system (PVDF vs SMP) they’re quoting, and how they handle fastening — panels should go up with slotted-hole fasteners left slightly loose, never driven tight. A contractor who can’t explain how their fastening method accommodates thermal expansion is a strong warning sign for a metal installation specifically, since that detail is what prevents buckling and noise over the long run.

Metal Siding FAQ

Is aluminum or steel siding better?

Aluminum won’t rust even if scratched to bare metal, making it a strong choice in coastal or humid environments, while steel resists denting far better, making it the stronger choice in hail-prone regions; neither is universally “better,” and the right pick depends on which failure mode — dents or rust — matters more in your climate.

Does steel siding rust?

Residential steel siding is coated with a rust-inhibiting layer (galvanized or Galvalume) beneath the paint finish, and as long as that coating stays intact it won’t rust; rust becomes a risk only where the coating is scratched, cut, or breached down to bare metal and left untreated.

Can dented metal siding be repaired?

Individual damaged panels can typically be unclipped and replaced, but a dent in an installed aluminum panel generally can’t be reshaped back to flat, which is why isolated impact damage is usually addressed through panel replacement rather than reshaping.

How long does metal siding last?

Both aluminum and coated steel siding commonly last 40 to 70 years, with the coating quality (PVDF versus SMP) and the local climate driving most of the variation in how long the finish holds its color before fading or chalking.

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