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March
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Galvalume was introduced to the construction industry by Bethlehem Steel in the early 1970s as an advanced alternative to galvanized steel. Due to its superior durability and corrosion resistance, more than 90% of the metal roofing industry transitioned from galvanized steel to Galvalume substrates by the mid-to-late 1990s.
Galvalume roofing sheets is a fusion of three key metals used in roofing: steel, aluminum, and zinc. The manufacturing process begins with a cold-rolled carbon steel base sheet, which is continuously hot-dipped in an aluminum-zinc alloy (AZ) coating. This coating consists of 55% aluminum, 43.4% zinc, and 1.6% silicone, combining the strengths of each metal to create a highly durable and corrosion-resistant material.
Due to these benefits, Galvalume has become one of the most widely used metals in roofing applications. It is often categorized by its coating weights, AZ-50 and AZ-55:
- AZ-50: Contains 0.50 ounces of aluminum-zinc alloy per square foot, applied to both sides of the substrate. This is the standard coating weight for painted sheet and coil products.
- AZ-55: Contains 0.55 ounces of aluminum-zinc alloy per square foot, applied to both sides of the substrate. It is the standard for bare or unpainted products, commonly referred to as acrylic-coated Galvalume or Galvalume Plus.
Acrylic-coated Galvalume has a slightly heavier coating and includes a thin acrylic layer that protects the Galvalume coating during manufacturing. Over time, this layer wears off with exposure. While not painted, these products still require careful handling to prevent scuffing or damage to the protective coating.
Overall, Galvalume is suitable as a roof, wall, trim, accent, and more in most building applications in some of the most extreme environments, including non-coastal hurricane zones, locations with high rain or snowfall, high-temperature regions, and more.
- Commercial Buildings – Hospitals, schools, retail stores, government facilities, and more.
- Residential Projects – Single-family homes, multi-family units, condominiums, and other housing developments.
- Architectural Structures – Used in commercial, governmental, and residential designs for both aesthetic and functional purposes.
- Structural & Industrial Applications – Ideal for warehouses, factories, and other industrial facilities.
- Agricultural Use – Common in barns, storage buildings, and non-animal confinement spaces.
While Galvalume is a highly durable and versatile material, there are certain environments where it is not recommended due to its susceptibility to premature corrosion and failure.
Galvalume should not be used in buildings that house animals. Over time, manure decomposes and releases ammonia gas, which reacts with the aluminum-zinc coating, leading to rapid degradation of the metal. However, some modern chicken houses incorporate a vapor barrier between the poultry area and the roof for adequate ventilation, allowing limited use of Galvalume. Before using Galvalume in animal confinement structures, consult the manufacturer to determine suitability based on the building’s design.
Galvalume is not suitable for coastal areas, especially in locations exposed to breaking surf, large bays, marshes, or other saltwater-rich environments. The high salt concentration in the air accelerates the breakdown of the Galvalume coating, leading to premature damage. For buildings near the coast, an engineered aluminum roofing system is recommended, as aluminum provides superior resistance to corrosion and rust caused by saltwater exposure.
If your project is located in a potentially corrosive environment or you’re unsure about the suitability of Galvalume for your location, consult the manufacturer for guidance on the best material choice.
Galvalume is engineered to combine the durability and self-healing properties of zinc with the corrosion resistance of aluminum. As a result, it offers two to four times better protection against rust compared to galvanized steel.
One of Galvalume’s standout features is its ability to minimize red rusting at cut or exposed edges. Like most steel-based materials, it may experience slight edge creep when cut, but this process is minimal and eventually stabilizes. Edge creep can also be managed by hemming panels and applying touch-up paint to exposed edges for added protection.
Unlike more delicate metals like copper or zinc, Galvalume is durable and less prone to visible scratches, fingerprints, or surface damage during installation. Additionally, it does not have strict ventilation or air gap requirements, making it a more forgiving material for roofing applications.
Since Galvalume is a standard roofing product, its installation follows common industry practices without requiring specialized techniques. Despite its toughness, it remains easy to handle, rollform, and cut, simplifying the installation process for contractors.
Studies suggest that Galvalume roofing can last 50+ years in suitable conditions with minimal corrosion. This longevity makes it an attractive option for property owners seeking a durable, low-maintenance roofing system, unlike asphalt shingles, which often require replacement every 10–15 years.
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