Jul 22, 2025

Galvalume vs Galvanized: Which Coating is Best for Your Building?

When choosing materials for your next metal building project or metal roof system, it’s important to consider the type of protective coating used. Two of the most common options – Galvalume and Galvanized – offer excellent corrosion resistance, but they perform differently depending on the environment and application. Let’s take a closer look at these options.

Understanding the Basics

Galvanized steel is coated with a layer of zinc to protect the base metal from corrosion. This traditional method has been used for decades and is still widely trusted for its durability and affordability.

Galvalume steel, on the other hand, is coated with a zinc-aluminum alloy (typically 55% aluminum, 43.4% zinc, and 1.6% silicon). This composition enhances corrosion resistance, especially in more challenging environments.

Performance Comparison: Galvalume vs Galvanized

Which Coating Is Best for Your Application?

Metal Roof Coatings
- If you're installing a roof and expect it to endure a variety of weather conditions – especially in coastal or humid regions – Galvalume typically outperforms Galvanized in long-term protection. It offers better thermal reflectivity and corrosion resistance, especially near the ocean or in high-moisture climates.
Steel Siding
- For wall cladding and exterior panels, both options are viable. Galvalume’s smoother finish and longer life make it ideal for pre-painted steel applications. Galvanized may be preferred in environments where abrasion resistance is a higher priority.
Metal Buildings and Framing
- Interior structural framing, purlins, and girts often use Galvanized steel, especially in controlled environments. It’s cost-effective and easy to fabricate. However, if you're building a structure exposed to the elements, Galvalume will provide a longer service life.

Painted Steel Considerations

Galvalume offers a better surface for paint adhesion due to its smoother finish. Painted Galvalume panels are commonly used in architectural and residential metal buildings, offering aesthetic appeal along with superior durability.

Corrosion Resistance in Real-World Environments

According to Metal Construction Association, field studies have shown that Galvalume lasts 2–4 times longer than Galvanized in marine and industrial atmospheres – making it a smart investment for projects where longevity matters.

Final Thoughts

When it comes to selecting between Galvalume vs Galvanized steel, there’s no one-size-fits-all answer. Your application, budget, and environmental conditions guide the best choice.

Need Help Choosing the Right Coating?

Mill Steel’s knowledgeable team is here to help you choose the best option based on your building’s location, performance requirements, and aesthetic preferences. We offer a wide selection of Galvalume and Galvanized products—including painted steel—ready to ship nationwide.