If you've shopped for a metal roof, you've seen the word "Galvalume" everywhere — but few homeowners are told what it actually means. Here's the plain-English version.
What Galvalume is
Galvalume is steel coated with an aluminum-zinc alloy — roughly 55% aluminum, 45% zinc, with a bit of silicon. That coating is the secret to why metal roofs last so long: the aluminum forms a tough, corrosion-resistant barrier, while the zinc provides "sacrificial" protection that guards the steel at scratches and cut edges. Together they protect the steel underneath far better than either coating alone.
How it protects your roof
Bare steel rusts fast. The aluminum in Galvalume creates a stable, protective layer that resists corrosion, and the zinc actively protects any exposed spots. The result is a roofing panel that can last 40+ years even in tough weather.
Where Galvalume is used
Galvalume is the base material for most modern metal roofs — both standing seam and screw-down panel systems. It's used either bare (a silver, lightly spangled finish) or as the base under a painted color coat.
Galvalume vs. galvanized
Galvalume (aluminum-zinc) generally outperforms older galvanized (zinc-only) steel on corrosion resistance and lifespan, which is why it's become the industry standard. For a full breakdown, see our Galvalume vs. galvanized vs. painted guide.
Pros and cons
Pros: excellent corrosion resistance, 40+ year lifespan, great value, lightweight, and recyclable. Cons: bare Galvalume's silver finish isn't for everyone (many homeowners choose a painted version for color), and like all metal, cut edges should be handled properly during installation.
Is Galvalume good for Tennessee homes?
Yes — its corrosion resistance handles Middle Tennessee's humidity well, and its longevity means you install once instead of re-roofing every 15–20 years. For pricing, see our metal roof cost guide, or get a free estimate.