Understanding Galvalume® Metal Roofing: Key Benefits and Practical Uses

When considering a metal roofing system, you have a variety of material options, including aluminum, copper, zinc, galvanized, stainless steel, and Galvalume®. Among these, Galvalume is the preferred choice in architectural metal roofing due to its versatility and exceptional performance across numerous applications.

But how familiar are you with Galvalume metal? Do you understand its key benefits and drawbacks? At 50 North Roofing, we specialize in both painted and bare Galvalume for metal roofing and wall projects. We strive to ensure you make an informed purchasing decision. Let’s delve into the details of Galvalume and explore whether it suits your project needs.

This article covers:

  • What is Galvalume?
  • The Evolution of Galvalume
  • Composition and Variants of Galvalume
  • Applications of Galvalume
  • Benefits of Galvalume
  • Drawbacks of Galvalume

Also Read: Standing seam or exposed fastener metal roofing system

What is Galvalume®?

Galvalume metal is a steel product enhanced with a specialized coating of aluminum, zinc, and silicone. This combination grants Galvalume superior durability and resistance to corrosion, making it a popular choice for metal roofing and various building applications.

The Evolution of Galvalume®

Introduced by Bethlehem Steel in the early 1970s, Galvalume revolutionized the construction industry. Initially, galvanized steel was the standard for metal roofing. However, Galvalume’s superior durability and corrosion resistance led to a significant industry shift. By the mid to late 1990s, over 90% of the metal roofing industry had adopted Galvalume substrates.

Composition and Variants of Galvalume®

Galvalume metal integrates the strengths of steel, aluminum, and zinc. The manufacturing process involves continuously hot-dipping a cold-rolled carbon steel base sheet in aluminum and zinc alloys, achieving a coating composition of 55% aluminum, 43.4% zinc, and 1.6% silicone.

This unique blend provides Galvalume with the best qualities of each metal, making it a favored choice in metal roofing. Galvalume is also identified by its coating weights, AZ-50 and AZ-55:

  • AZ-50: Features 0.50 ounces per square foot of the aluminum-zinc alloy coating on both sides of the substrate, typically used for painted sheet and coil products.
  • AZ-55: Features 0.55 ounces per square foot of the aluminum-zinc alloy coating on both sides of the substrate, commonly used for bare or unpainted sheet and coil products. This variant includes a light acrylic coating that protects the Galvalume during manufacturing but wears off over time with exposure.

Applications of Galvalume® Metal Roofs & Walls

Galvalume metal is highly versatile, suitable for numerous building applications in extreme environments such as non-coastal hurricane zones, high-rain or snowfall areas, and high-temperature regions. Typical uses include:

  • Commercial buildings: Hospitals, schools, stores, government buildings, etc.
  • Residential projects: Single-family homes, multi-family dwellings, condominiums, etc.
  • Architectural structures: Commercial, governmental, residential structures, etc.
  • Industrial applications: Warehouses, factories, etc.
  • Agricultural buildings: Non-animal confinement spaces, barns, storage facilities, etc.

Benefits of Galvalume® Metal Roofing

Longevity

Studies show that Galvalume roofing can last over 50 years in optimal conditions without significant corrosion. This longevity makes Galvalume an excellent choice for property owners seeking a durable roofing system that won’t require frequent replacements, unlike asphalt shingles.

Corrosion Resistance & Self-Healing Properties

Galvalume’s composition blends the durability and self-healing properties of zinc with the corrosion resistance of aluminum. This results in corrosion resistance that is two to four times better than galvanized steel. Galvalume’s self-healing properties minimize red rust at exposed edges, reducing the likelihood of field failures.

Ease of Handling & Installation

Galvalume is more resilient than other metals like copper and zinc, making it easier to handle and install. Installers don’t need to worry as much about fingerprints or deep scratches, and the material has fewer ventilation or air gap requirements. Despite its toughness, Galvalume is easy to handle, rollform, and cut.

Economical & Competitive Pricing

Galvalume metal is cost-effective, offering one of the most affordable options for metal roofing materials. Prices typically range from $5.00 to $15.00 per square foot, depending on thickness, color, and quality. However, steel prices can fluctuate, so prices may vary.

Warranty Protection

Galvalume metal comes with a 25-year substrate warranty, often referred to as a perforation warranty, and additional paint warranties. Commercial property owners can also opt for a weathertight warranty to ensure proper installation. Note that substrate or paint warranties are not available for Galvalume products within 1,500 feet of a coast.

Drawbacks of Galvalume® Metal Roofing

Oil Canning

Oil canning refers to the waviness or distortion in the flat surfaces of metal panels. While it doesn’t impact the system’s strength or performance, it can be aesthetically unpleasing. To minimize oil canning, use thicker sheets, buy from reputable brands, and hire experienced contractors.

Material Interactions

Combining different metals in a roofing system can lead to early degradation. Galvalume should not contact copper, lead, bricks, treated lumber, iron, and concrete. If exposed to water, these materials can cause galvanic corrosion.

Scuffing on Unpainted Galvalume

Unpainted Galvalume can scuff easily in high-traffic areas, damaging the acrylic coating. Once scuffed, the only remedy is panel replacement. To avoid this, limit foot traffic on newly installed panels and be cautious with ladder placement.

Situations Where Galvalume Should Not Be Used

Despite its advantages, Galvalume is not suitable for all environments:

  • Animal enclosures: Manure from animals breaks down into ammonia gas, which reacts with and degrades the Galvalume coating.
  • Coastal environments: The aluminum-zinc coating does not withstand high salt exposure, leading to premature damage.

Final Thoughts on Galvalume® Metal Roofing

Galvalume is an excellent choice for many roofing projects, but it’s essential to know when it is and isn’t appropriate. To recap:

  • Galvalume is designed to last for decades in suitable environments.
  • It has self-healing properties that control red rust at exposed edges.
  • It’s easy to handle and install, with minimal special requirements.
  • It offers various warranty options, including paint, substrate, and weathertight warranties (for commercial applications only).
  • It is unsuitable for coastal environments or animal enclosure structures.

At 50 North Roofing, we are committed to educating customers to help them make informed decisions about the best metal material for their roofing projects—whether it’s Galvalume or another option. Whether you’re a homeowner, contractor, architect or commercial property owner, we can help you choose the right product for your needs.

For more information, visit our website or contact us today to discuss how Galvalume metal roofing can benefit your building.