Everything You Need to Know About Al-Zn Coated Steel

When it comes to roofing and cladding materials, longevity, durability, and corrosion resistance are top priorities. In this regard, Aluminium-Zinc (Al-Zn) coated steel stands out as a superior choice—especially in harsh weather conditions like those experienced across Kerala.

Used extensively in roofing sheets, wall cladding, and structural applications, Al-Zn coated steel offers significant advantages over conventional galvanized steel. In this blog, we’ll break down what Al-Zn coated steel is, how it works, and why it’s considered a smarter investment for modern construction.

What Is Al-Zn Coated Steel?

Al-Zn coated steel is produced by hot-dipping a mild steel substrate into a special alloy of Aluminium (55%), Zinc (43.5%), and Silicon (1.5%). This creates a durable, corrosion-resistant surface that offers both barrier protection from aluminium and galvanic protection from zinc.

Unlike galvanized steel, which uses a pure zinc coating, the dual-action protection provided by the Al-Zn alloy ensures significantly enhanced resistance to oxidation, rusting, and environmental damage.

Benefits of Al-Zn Coated Steel

✅ Superior Corrosion Resistance

Thanks to the Aluminium-Zinc combination, these coated sheets last up to 2–4 times longer than standard galvanized steel in similar environments. The aluminium in the coating acts as a long-term barrier against environmental factors, while the zinc offers localized protection at scratches or cut edges.

✅ Better Performance Against Rust

While galvanized steel corrodes in a linear manner—eventually depleting the entire zinc layer—Al-Zn coated steel corrodes much slower and in a more localized manner. Even after decades, the metal retains its integrity and functionality.

✅ Ideal for Organic Coating

Al-Zn coated steel is an excellent substrate for further organic coatings or paints. Its matte finish enables direct paint application without requiring additional surface treatment—making it ideal for aesthetically superior colour-coated roofing and cladding products like Tata BlueScope’s DURASHINE® sheets.

✅ Aesthetic Advantage

Al-Zn coated steel has a smoother, matte appearance, offering a clean and modern look, unlike the shiny “spangle” finish of regular galvanized steel.

Where Is It Used?

Al-Zn coated steel is widely used in:

• ✅ Roofing sheets & wall cladding (residential, commercial, and industrial buildings)
• ✅ Structural components
• ✅ Pre-engineered buildings
• ✅ Garage doors, water tanks, silos, and air conditioning ductwork

In brands like DURASHINE®, offered by Tata BlueScope Steel, Al-Zn coated steel forms the base of their high-performance, long-lasting roofing products. The Al-Zn coating technology is what enables these roofs to resist corrosion, fade less over time, and stay structurally sound even in coastal or high-moisture regions like Kerala.

Conclusion

In summary, Al-Zn coated steel is a game-changer for anyone looking for strength, style, and sustainability in roofing and structural applications. Its superior corrosion resistance, ease of coating, and long lifespan make it a smarter, more cost-effective choice over traditional galvanized steel.

Whether you’re a contractor, builder, or homeowner, choosing Al-Zn coated steel ensures that your investment is built to last.

Modern Distropolis Limited proudly distributes Al-Zn based roofing solutions like DURASHINE®, offering unmatched service and quality.