# Aluminum vs Steel Metal Roofing in Ontario: Which Should Your Home Get?

> For most Ontario homes, coated steel is the right metal roof: it costs $10–$18 per square foot installed in the GTA against $14–$22 for aluminum, it is stronger and more dent-resistant, and with a Galvalume or galvanized base and a quality paint system it lasts 40–60 years in our climate. Aluminum earns its premium where corrosion is the enemy — within a few kilometres of Lake Ontario, on very low-slope sections, or wherever salt spray and standing moisture are constant — because it cannot rust. Both outlast asphalt shingles two to three times over.

*Category: roofing | 8 min read | Updated 2026-10-01*

## Side by side

|  | Coated steel | Aluminum |
| --- | --- | --- |
| Installed cost (GTA, 2026) | $10–$18 per sq ft | $14–$22 per sq ft |
| Typical lifespan | 40–60 years | 50–70 years |
| Rust / corrosion | Protected by Galvalume or galvanized coating; cut edges and scratches are the risk | Cannot rust; forms its own protective oxide |
| Dent resistance | High — 26- or 24-gauge steel shrugs off hail and ladders | Lower — softer metal shows hail and foot traffic |
| Thermal movement | Moderate | Higher — needs clips and details that allow more expansion |
| Weight | About 1–1.5 lb per sq ft | About 0.5–0.9 lb per sq ft |
| Best use | Most GTA houses, steep and moderate slopes, hail-prone areas | Lakefront, low-slope sections, salt exposure, cottages |

## Cost: why aluminum is 25–40% more

Aluminum coil costs more per pound than steel and, because it is softer and moves more with temperature, standing-seam aluminum systems use thicker stock and more clips to stay flat and quiet. In the GTA that works out to $14–$22 per square foot installed for aluminum against $10–$18 for steel, including tear-off, deck repair, underlayment, flashing and the panels. On a typical 1,800 sq ft roof the difference is $7,000–$9,000. Metal shingle profiles are slightly less than standing seam in both materials.

## Lifespan in Ontario's climate

Ontario roofs see 40 or more freeze-thaw cycles a winter, ice at the eaves, summer surface temperatures above 60 °C and, increasingly, hail. Both metals handle all of that far better than asphalt, which is why either one is routinely the last roof a house gets. The difference is how they fail at the margins. Steel's weakness is corrosion at scratches, cut edges and fastener penetrations once the coating is breached; that is managed with Galvalume (aluminum-zinc) or heavy galvanized substrates, factory-painted finishes and concealed-fastener systems, and it is why we quote 40–60 years for a properly installed steel roof. Aluminum's weakness is denting and thermal movement; it will never rust, which is why it reaches 50–70 years and is the default choice on lakefront and cottage roofs.

Manufacturers warrant the paint finish on both for 30–50 years. Buildoreno adds a 10-year written labour warranty on the installation, and we use synthetic underlayment and ice-and-water shield at eaves and valleys on every metal roof regardless of material.

## When steel is the right call

- Most detached, semi-detached and townhouse roofs in Toronto, Mississauga, Brampton, Vaughan and Markham, where corrosion exposure is ordinary.
- Hail-prone and high-traffic roofs (satellite installers, chimney sweeps, Christmas lights) — steel does not show the dents.
- Budgets where the $7,000–$9,000 difference is better spent on standing seam over metal shingles, or on attic ventilation and insulation.
- Dark colours and large uninterrupted panels, where aluminum's extra thermal movement is hardest to hide.

## When aluminum is worth the premium

- Within a few kilometres of Lake Ontario — Port Credit, the Beaches, Oakville's lakeshore, Burlington — where moist, salt-carrying air finds every scratch in a steel coating.
- Low-slope sections and valleys that hold water or ice through the winter.
- Cottages and waterfront properties in Muskoka and on Georgian Bay.
- Anywhere the roof will be hard to inspect or touch up for decades.

> Whichever metal you choose, the installation details matter more than the material. Concealed fasteners, correct clip spacing, proper underlayment and real flashing at every penetration are where 40-year roofs and 15-year roofs part ways.

## A note on copper, zinc and 'stone-coated' steel

Copper ($22–$45+ per sq ft) and zinc are lifetime materials with distinctive patinas, chosen for appearance rather than economics. Stone-coated steel shingles are ordinary coated steel with a granular acrylic finish that mimics shake or tile; they cost about the same as painted metal shingles and perform the same, so pick them on looks.

**Q: Does a steel roof rust in Ontario?**

Not when it is a coated product — Galvalume or galvanized steel with a factory paint system — installed with concealed fasteners and properly sealed cut edges. Bare or scratched steel will. Cheap exposed-fastener agricultural panels are where the 'metal roofs rust' reputation comes from.

**Q: Which is better for a flat or low-slope roof?**

Aluminum, if you are using a metal system at all, because low slopes hold moisture. For slopes under about 3:12 we usually recommend a membrane — TPO, EPDM or modified bitumen — rather than metal of either kind.

**Q: Is aluminum roofing noisy or hot?**

No more than steel. Noise comes from panels fastened straight to purlins with no underlayment; a residential installation over a solid deck with underlayment and attic insulation is as quiet as asphalt. Both metals reflect more summer heat than asphalt and typically cut cooling costs by 10–25%.

**Q: Can either metal go over my existing shingles?**

Sometimes, with one layer of shingles in sound condition and a deck that passes inspection. We usually recommend a tear-off so the deck can be repaired and the underlayment and ice-and-water shield installed correctly; it adds $1.50–$3.00 per sq ft and removes the risk of trapping moisture under a 50-year roof.

## Related Services
- [Metal Roofing](https://buildoreno.ca/metal-roofing)
- [Standing Seam Metal Roofing](https://buildoreno.ca/metal-roofing/standing-seam)
- [Metal Shingle Roofing](https://buildoreno.ca/metal-roofing/metal-shingles)
- [Metal Roof Cost Guide](https://buildoreno.ca/metal-roof-cost-toronto)

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