The 3‑in‑1 Coated Steel
Galvalume steel combines the barrier protection of aluminum with the galvanic protection of zinc. CNB’s GL coils, coated with 55% Al, 43.4% Zn, and 1.6% Si, outperform GI 2‑4 times in long‑term atmospheric exposure. This makes it the preferred bare (unpainted) roofing and cladding material in tropical, coastal, and rural environments. Additionally, its high thermal reflectivity reduces building cooling loads.

Product Highlights

• Corrosion Resistance: Salt spray tests demonstrate GL performs 3‑5 times better than GI of equal coating thickness. Cut‑edge protection is superior due to aluminum’s barrier effect.

• Heat Resistance: Continuous service up to 315°C without discoloration, ideal for uninsulated industrial roofs and oven outer panels.

• Heat Reflectivity: Reflects up to 80% of solar radiation, helping meet cool‑roof building codes.

• Cost Efficiency: At equal coating mass, GL covers 3‑5% more area due to the lower density of the Al‑Zn alloy.

Standard Specifications

• Thickness: 0.14mm – 2.0mm

• Width: 600mm – 1250mm (914mm, 1000mm, 1200mm, 1219mm, 1220mm)

• Coating: AZ30 – AZ275 g/m² (double side)

• Spangle: Minimized / small spangle (typical for GL)

• Grades: DX51D+AZ, S220GD+AZ, S250GD+AZ, S300GD+AZ, S350GD+AZ