Decision Guide
Steel vs. Aluminum Roofing: Which Is Right for You?
A direct comparison of steel and aluminum metal roofing for Boise, Idaho — cost, corrosion resistance, weight, and when each makes more sense in an inland climate.
Steel is the more common, typically more economical choice in Boise's inland climate, running $10-16/sq ft versus aluminum's $11-17/sq ft. Aluminum is worth considering mainly for weight-sensitive structures or properties with heavy irrigation overspray, since its main advantage — coastal corrosion resistance — matters less here than near an ocean.
Published 2026-08-23 · Updated 2026-08-23
The core difference
Both steel and aluminum are common, well-established metal roofing materials, and the choice between them comes down to a handful of practical factors rather than one being objectively “better.” Steel is the default choice in most inland U.S. markets, including Boise; aluminum is more common in coastal regions where its natural corrosion resistance is the deciding factor.
Cost comparison
| Steel | Aluminum | |
|---|---|---|
| Installed cost (standing seam) | $10-16/sq ft | $11-17/sq ft |
| Installed cost (exposed-fastener) | $7-12/sq ft | Similar range, less common |
| Weight | Heavier | Roughly 1/3 lighter than steel |
| Corrosion resistance | Good with proper Galvalume/galvanized coating | Naturally superior, especially in salt-air/coastal environments |
| Denting resistance | Better at comparable gauge | Softer; dents more easily unless heavier gauge is used |
Why steel is the practical default here
Boise’s inland, low-humidity climate doesn’t demand aluminum’s signature advantage — coastal corrosion resistance — the way a marine environment would. A properly coated steel panel (Galvalume AZ50 or G90 galvanized) performs reliably in this climate for decades, at a typically lower cost than aluminum. That’s why the large majority of metal roofs installed in the Treasure Valley are steel.
When aluminum is worth considering
- Weight-sensitive structures. Aluminum’s lighter weight matters on older framing or accessory structures where reducing roof load is a real structural consideration, not just a preference.
- Heavy irrigation overspray. Properties where sprinkler systems consistently mist a lower roof or valley section see real value in aluminum’s superior corrosion resistance, since even Galvalume-coated steel can show premature edge wear under sustained moisture exposure.
- Specific finish or color preferences. Some finish options and color ranges are more readily available or perform differently on aluminum versus steel — worth discussing if you have a specific aesthetic goal.
Galvanic corrosion: the reason not to mix them casually
When steel and aluminum come into direct contact with moisture present, a galvanic reaction can accelerate corrosion at the contact point — a real consideration for gutters, flashing, and fastener choices anywhere the two metals might touch. This is a detail we account for specifically in fabrication and hardware selection, not something to leave to chance.
Bottom line
For most Boise-area homes, steel is the practical, cost-effective default — Galvalume or better resists this climate’s conditions well, at a lower cost than aluminum. Aluminum earns its keep on weight-sensitive structures or properties with real irrigation-overspray exposure. We’ll walk through which fits your specific situation at the free on-site estimate. Call (208) 279-6903.
The bottom line
If you want this priced for your own roof rather than in ranges, we come out and inspect at no charge across Boise and the Treasure Valley. You get a written per-square price with tear-off and any deck repair broken out separately. Call (208) 279-6903.