Aluminum siding is the thin, painted metal cladding that wrapped millions of US houses between the late 1940s and the 1970s — and much of it is still up, still straight, and still shedding water. New aluminum installed costs about $8 to $16 per sq ft. Repainting the wall you already have runs $1.50 to $4 per sq ft with a contractor — the best-value move for most owners.
The material is simple: aluminum sheet rolled thin, formed into laps or vertical panels, and finished with a factory-baked enamel. It weighs about a third as much as steel, never rusts, and skins over with a protective oxide. What it will not do is resist a dent, and that one weakness drives every real decision about it.
This guide covers what aluminum siding is, its honest failures, how to refinish a sound wall for a fraction of the cost of re-siding, and when repainting is money down a hole.
What Aluminum Siding Is, and Why So Much of It Is Still Up
Residential aluminum is specified in inches, not gauge: 0.019 to 0.032 in. thick, with 0.024 to 0.027 the common range on mid-century horizontal lap. A square — 100 sq ft of wall — of 0.024 in. aluminum weighs roughly 30 to 35 lb, light enough to hang over existing wood clapboard without asking much of the framing.
Horizontal lap panels 8 to 12 in. tall, with a nailing hem at the top, imitate clapboard and cover most ranch houses and capes. The finish is a factory coil coating — a baked enamel applied before the metal is formed — which is why it outlasts anything sprayed onto a finished wall.
Aluminum does not rust because of chemistry. Exposed to air it forms an oxide layer in minutes that is hard, tightly bonded, and self-healing: scratch it and it grows back. Iron oxide flakes away and keeps eating; aluminum oxide seals the surface. That is why the post-war boom fell for it — mills that had rolled aircraft skin had capacity to spare, and aluminum was suddenly cheap. From roughly 1950 to 1975 it clad a huge share of new American housing.
| Material | Thickness / weight | Installed cost / sq ft | Service life | Best used for |
|---|---|---|---|---|
| Aluminum | 0.019–0.032 in.; ~1/3 the weight of steel | $8–$16 | 30–50 yrs | Salt air, light framing, re-siding over wood |
| Steel | 24–29 ga; rusts at cut edges | $7–$15 | 40–60 yrs | Hail belt, modern profiles |
| Fiber cement | 5/16 in.; heavy, needs two people | $9–$18 | 30–50 yrs | Hail, fire zones, holds paint |
Where Aluminum Wins, and Where It Does Not
Aluminum earns its place in three situations. Coastal salt air is the first: salt attacks steel at every cut edge and fastener, while aluminum shrugs it off, which is why beach towns from the Jersey Shore to the Gulf still favor it. Low-rise buildings are the second — a two- or three-story wall of light panels asks nothing of the structure. Weight-sensitive re-sides are the third: when you are covering old wood siding, or working on a manufactured home or a dormer, aluminum’s low weight is the whole argument.
It is the wrong choice in the hail belt. Across Texas, Oklahoma, Kansas, and Colorado, aluminum turns into a golf ball within a season or two; that market belongs to fiber cement and heavier steel. It is also wrong beside a driveway or a basketball hoop, and for anyone who cannot live with a surface that records every impact. For the metal look without the dent risk, compare profiles in our metal siding guide.
Dents, Noise, and Galvanic Corrosion
Denting is the headline weakness. A thrown ball, a ladder, a mower stone — each leaves a permanent concave bruise no paint hides, because the damage is in the plane of the surface and raking light finds it. Aluminum is soft; that is the trade for rust-proof and light.
Noise is the second complaint, and it is real. On an open stud wall with no sheathing, rain and hail drum loudly; if that wall backs a bedroom you will hear it. Solid sheathing and insulation backing cut it substantially.
Corrosion is the third, and it surprises people. Aluminum reacts with dissimilar metals: set it against copper flashing or ACQ pressure-treated lumber, and in the presence of moisture the aluminum becomes the sacrificial anode and pits. The fix is separation — a barrier, a coating, or the right fastener — never contact. Copper gutters touching aluminum siding is a classic, preventable failure.
The fourth failure is the finish. Factory-baked enamel eventually chalks: the resin breaks down into a powdery film that streaks down the wall and will not accept new paint until it is washed and deglossed.
Refinishing an Existing Aluminum Wall: The Best-Value Play
If the panels are sound — no dents visible in raking light, no corrosion blisters, no crushed bottom lock, no water getting behind them — repainting is the best money you can spend on the house. A professional repaint runs $1.50 to $4 per sq ft, against $8 to $16 to tear the siding off and re-side, and only $4 to $9 for vinyl. On a 1,800 sq ft single-story house with roughly 2,000 sq ft of wall, that is a $3,000 to $8,000 repaint against a $16,000 to $32,000 re-side.
Preparation is the whole job. Wash the wall with a siding cleaner and a stiff brush, bottom to top, then rinse top to bottom. Kill mildew with a diluted bleach solution and rinse again. Then degloss: scuff the chalked factory finish with a pad or apply a liquid deglosser so the new coating has something to bite. Skip that step and the paint peels in sheets within three years.
Prime with a bonding primer made for hard, glossy surfaces, or a waterborne acrylic metal primer where the aluminum is bare. Topcoat with 100% acrylic exterior paint, two coats, flat or satin. Acrylic stays flexible as the metal moves. Avoid oil-based paint and “paint-and-primer-in-one” products over chalk; both fail early on aluminum.
Expect 8 to 12 years between repaints, and about $0.50 to $1.00 per sq ft in materials if you do it yourself. If the existing paint is lead-based, likely on pre-1978 homes, test it before you sand or scrape.
Field note: If a painter quotes a repaint without mentioning deglossing or a bonding primer by name, they plan to roll latex straight over chalk. That job looks good for two years and peels for the next five.
Know when to stop, too. Repainting a wall with twenty visible dents, corroded seams, or panels that oil-can in the wind is throwing money at a surface that needs to come off. Paint hides color; it does not hide geometry.
Buying New Aluminum: Cost, Insulation, Movement, and Fastening
New aluminum installed lands at $8 to $16 per sq ft, with material alone at $4 to $8. Labor is usually cheaper than fiber cement because the panels are light and cover a lot of wall in a day. Trim — corners, J-channel, rake caps — is where the bill grows, especially on a complicated roofline.
Insulation backing is worth the upcharge. A factory-laminated foam or foil-faced board adds roughly R-2 to R-4 and takes most of the drum out of a rainstorm. Over old sheathing it also flattens minor irregularities.
Aluminum moves with temperature — about 1/8 in. per 10 ft of panel across a 100°F swing. That is why panels need to hang, not be pinned. Use aluminum or stainless fasteners, set them in slotted holes, and drive them snug but not tight so the panel can slide. Nail it rigid and the wall oil-cans in the sun and shears its own fasteners.
Two details decide whether the wall lasts. Keep aluminum off ACQ-treated lumber and away from copper flashing with a barrier, and hold the bottom edge 6 in. above grade over a weather-resistive barrier with flashing at openings. Aluminum is forgiving, but it is not a drainage plane.
Frequently Asked Questions
Does aluminum siding rust?
No. It forms a hard oxide skin that seals the surface and regrows when scratched. It can still corrode where it touches copper, ACQ-treated lumber, or another dissimilar metal in the presence of moisture — a contact problem, not a rust problem.
How much does it cost to repaint aluminum siding?
Professionally, $1.50 to $4 per sq ft, including cleaning, deglossing, priming, and two coats of 100% acrylic. DIY materials run about $0.50 to $1.00 per sq ft. Expect 8 to 12 years between repaints, less if the last painter rolled over chalk.
Does aluminum siding dent in hail?
Yes, and easily. Soft aluminum takes dents from ordinary hail and from thrown balls, ladders, and mower stones. No paint hides them, because the dent changes the plane of the wall and raking light exposes it. In the hail belt, choose fiber cement or heavier steel.
How long does aluminum siding last?
The metal lasts 30 to 50 years or more; the factory finish is the shorter-lived part, chalking and fading in 15 to 25 years. That is why refinishing beats replacement when the panels are still flat.
The Bottom Line
Aluminum siding is a genuinely good material with one real flaw. If your house already has it and the panels are straight, repaint it properly — clean, degloss, prime, two coats of 100% acrylic — and you will buy another decade for a fraction of re-siding cost. If you are buying new, choose aluminum for coastal salt air, low-rise walls, and weight-sensitive re-sides, and walk away from it in the hail belt. Where it fits, it is light, rust-proof, and quietly permanent. Where it does not, you will spend the next twenty years looking at every dent.
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.
