Are you looking to invest in a durable, long-lasting, and versatile roofing material? Perhaps you've heard of Galvalume metal roofing and are curious to learn more about its properties, benefits, and applications. As seasoned professionals in the roofing industry, we at GIDEON are excited to share our insights and expertise on this innovative material.

Galvalume, first introduced in the 1970s, has significantly transformed the world of metal roofing, setting new standards for resistance to corrosion and durability.

But it's not suitable for every building. Install it on a building near the ocean or on a horse barn and you'll find yourself with an expensive heap of scrap metal.

In this article, we'll walk you through everything you need to know about Galvalume metal roofing, its pros and cons, comparison with other roofing materials, the best applications for its use, as well as what designs, colors, and finishes are available.

Table of Contents

• What Is Galvalume Metal Roofing?
• Pros of Galvalume Metal Roofing
• Cons of Galvalume Metal Roofing
• Best Applications for Galvalume
• Comparing Galvalume, Galvanized Steel, and Aluminum
  • Galvalume vs. Galvanized Steel
  • Galvalume vs. Aluminum
• Types of Galvalume Metal Roofing Systems
  • Standing Seam Metal Roofs
  • Corrugated Metal Roofs
  • Metal Tile Roofs
  • Metal Shingle Roofs
  • R-Panel Metal Roofs
  • PBR Panel Roofs

What is Galvalume Metal Roofing?

For decades, galvanized steel (steel coated with zinc), was the go-to choice for metal roofing because it protected the underlying steel, which is prone to rust when exposed to water. It served its purpose well, but, as with everything in the world of construction, there was room for improvement.

Enter Galvalume.

Introduced in the 1970s by Bethlehem Steel Corporation, Galvalume possesses twice the corrosion resistance of galvanized steel.

Galvalume is a sheet of steel coated with a unique alloy, a mix of 55% aluminum, 43.4% zinc, and 1.6% silicone. The metal is dipped into this hot, molten mixture and emerges with the inherent resistance of aluminum to rust and the ability of zinc to act as a sacrificial layer (taking on rust in place of the underlying steel).

Pros of Galvalume Metal Roofing

Superior Corrosion Resistance: The primary benefit of Galvalume roofing lies in its remarkable resistance to corrosion. It outperforms traditional galvanized steel by up to four times, thanks to its innovative coating blend. This attribute ensures Galvalume stands up well in numerous environmental conditions, from coastal to industrial areas, making it a long-lasting option for a wide range of projects.

Long Lifespan: Galvalume is known for its durability and longevity. Even in harsh weather conditions, Galvalume roofs can last 40+ years. This extended lifespan offers cost-savings in the long run, as it minimizes replacement and maintenance expenses.

Great Heat Reflectivity: One key advantage of Galvalume is its high heat reflectivity, which can help reduce cooling costs during hot weather. This characteristic makes it an energy-efficient choice for roofing, especially in regions with high temperatures.

Versatility and Aesthetics: Galvalume comes in various finishes, including pre-painted versions that offer a wide array of color choices, enhancing the aesthetic versatility of the product. Unpainted Galvalume provides a sleek, modern, and distinctive metallic appearance, which can be a design asset.

Economically Viable: Despite its superior properties, Galvalume is priced competitively, often comparable to or less than galvanized steel.

Self-healing Edges: Galvalume's blend of aluminum and zinc gives it self-healing properties that protect it, especially at cut edges. If a small area of the steel core becomes exposed, the coating will form a protective barrier, preventing further corrosion.

Environmentally Friendly: Galvalume® is also an environmentally friendly choice, as it is recyclable without losing any of its characteristics or quality.

Cons of Galvalume Metal Roofing

Oil Canning: This is a phenomenon seen as a waviness or distortion in the flat surfaces of metal panels, often referred to as "oil canning." It is inherent to light-gauge, cold-formed metal products like Galvalume®. Although oil canning does not impact the performance of the roof, it looks ugly. There are ways to minimize this effect, such as purchasing thicker sheets, selecting high-quality brands, implementing correct installation practices, and ensuring no inconsistencies in the roof decking.

Interactions with Other Materials: When used in combination with certain materials or elements, Galvalume® could lead to detrimental interactions. For instance, Galvalume® should not be in contact with copper, lead, bricks, treated lumber, iron, or concrete, as it could lead to galvanic corrosion, especially when an electrolyte such as water is introduced.

Scuffing Concerns: For non-painted Galvalume®, the acrylic coating on the panels' top can scuff, particularly in high-traffic areas. Once scuffed, the panel's appearance cannot be repaired, other than by replacing the affected panels. Over time, scuffed and exposed areas might weather and age quicker, leading to a splotchy appearance.

Not Suitable for Animal Confinement: Galvalume is not suitable for use in some agricultural applications, such as structures that house animals. This is because animal manure decomposes into ammonia gas, which reacts with the Galvalume coating, breaking it down over time.

Best Applications for Galvalume

Galvalume performs very well in most environments and climates, and can be used in residential (multifamily, single family) commercial (offices, stores, banks etc), institutional buildings (governments, schools, etc), and industrial buildings (warehouses, manufacturing facilities, etc). 

However, because of it's susceptibility to salt-water and ammonia gas, galvalume should not be used on coastal buildings or for animal enclosures. In the former, large quantities of salt will be deposited on the roof and break down the galvalume coating over time; in the latter, ammonia gas from decomposing manure will damage the coating.

Comparing Galvalume, Galvanized Steel, and Aluminum

Choosing the right material for your roofing project can significantly impact its longevity, performance, and aesthetics. In this comparison, we'll weigh Galvalume, galvanized steel, and aluminum against each other, examining their strengths, weaknesses, and suitable applications.

Galvalume vs. Galvanized Steel

Galvalume® and galvanized steel share a common trait: they're both derived from steel and enhanced for durability and corrosion resistance. Galvalume®, a combination of zinc, aluminum, and silicon, stands out from galvanized, for its self-healing properties, offering a barrier that protects against corrosion even at cut edges. In comparison, galvanized steel, which is coated with a layer of zinc, lacks this self-healing feature. Once its steel core is exposed, it begins to rust, leading to deterioration over time.

Galvalume® boasts a lifespan of over 40 years, more than double the 15-20 year lifespan of galvanized steel. While both materials are susceptible to oil canning, a visual distortion in the flat surfaces of galvanized metal panels, this is merely an aesthetic concern and doesn't impact the roof's performance.

However, Galvalume® is not recommended for use in animal confinement due to exposure to ammonia gas emitted from manure, which can react with elements of the coating. Galvanized steel, being more malleable and better-suited for such environments, wins in this regard.

From a cost perspective, these two materials have seen fluctuating prices, but as of 2022, galvanized steel was about 6% more expensive than Galvalume®.

Galvalume vs. Aluminum

In a comparison between Galvalume® and aluminum, several factors come to light. Both metals are highly durable and offer excellent corrosion resistance. However, aluminum edges out Galvalume® when it comes to coastal applications. Aluminum's inherent resistance to saltwater corrosion makes it the preferred choice in these environments.

Another consideration is weight. Aluminum is considerably lighter than Galvalume®, a property that can be beneficial for large structures where load-bearing is a concern. However, it's worth noting that this lightness comes with increased susceptibility to denting.

From a sustainability standpoint, aluminum shines. It is highly recyclable and can be repurposed without losing its quality, making it a more sustainable choice for green building projects.

However, all these benefits come at a cost—literally. Aluminum tends to be more expensive than Galvalume®, which could be a deciding factor depending on your project's budget.

Types of Galvalume Metal Roofing Systems

Galvalume metal is a versatile material that's used in various roofing systems. Here's a look at the main types:

Standing Seam Metal Roofs

This type of roof system is incredibly popular due to its modern aesthetic and exceptional weather-resistance. Standing seam roofs feature continuous panels running from the ridge of the roof down to the eaves. The panels are joined by raised seams (or vertical legs) that are crimped together, giving the roof system its name and distinctive appearance. A key advantage of Galvalume standing seam roofs is the hidden fastener system, which provides the roof with a clean look and minimizes the potential for water penetration.

Corrugated Metal Roofs

Another common application of Galvalume is in corrugated metal roofing. These roofs feature metal panels, with a waved pattern that offers both visual interest and structural strength. Corrugated Galvalume metal roofs are a durable and cost-effective choice for both residential and commercial buildings.

Metal Tile Roofs

For those who love the look of traditional tile but want the benefits of metal roofing, the Galvalume metal roof tiles offer the best of both worlds. These roofing systems mimic the appearance of classic clay, concrete, or slate tiles while providing the longevity, lightweight, and low maintenance benefits of a Galvalume metal top.

Metal Shingle Roofs

Similar to metal tiles, Galvalume metal roof shingles are designed to replicate the look of asphalt, wood, or slate shingles. They offer a more traditional aesthetic, making them a perfect choice for historic or older-style homes.

R-Panel Metal Roofs

Galvalume is also frequently used in R-Panel roofing systems, which are an excellent choice for commercial, industrial, and agricultural buildings. R-panels are strong, easy to install, and provide a high degree of protection.

PBR Panel Roofs

This is a type of R-panel where PBR stands for "Purlin Bearing Rib". This is a type of r-panel whose name dervies from its "purlin-bearing leg," an additional lip at the edge of the panel that increases the overlap between panels, making the roof more waterproof. 

Each of these Galvalume roofing systems brings unique advantages and aesthetic qualities. The best choice between them will depend on factors such as the architectural style of your building, your weather-resistance needs, and your budget.

Galvalume Colors & Finishes

Galvalume typically comes in a silvery, metallic finish due to the aluminum in the coating. However, Galvalume can also be painted, pre-treated, or coated with stone to achieve certain looks.

The specific availability of colors and finishes may vary by manufacturer, but here are some general categories you might expect:

1. Standard Colors: These are typically solid, opaque colors like white, black, gray, brown, and blue. They are often used for residential or commercial buildings where a more traditional aesthetic is desired.

2. Premium Colors: These colors might include more vibrant or unusual shades like red, green, or yellow. They might also include metallic or pearlescent finishes for a more unique look.

3. Stone-Coated: Some manufacturers offer Galvalume roofing with a special stone coating, which can give the appearance of other materials like wood or slate. This can be a good option for those who want the benefits of Galvalume but prefer a more traditional or natural look.

4. Cool Roof Colors: These are specially designed colors that reflect more sunlight and absorb less heat than traditional colors. They can help to reduce energy costs and improve indoor comfort, particularly in hot climates. Cool roof colors are often light in color, like white or light gray, but can also come in darker colors with special reflective properties.

5. Matte Finishes: Matte finishes are less glossy and reflect less light than standard finishes. They can give a more modern or understated look.

6. Aged or Weathered Finishes: These finishes are designed to look like the Galvalume has naturally weathered over time, giving it a rustic or antique look. This can be a popular choice for historic homes or other buildings where a newer, shinier roof might look out of place.

7. Clear Coats: Clear coats can be applied over the top of the Galvalume to provide additional protection against the elements. They can also add a glossier finish if desired.

The Upshot

Galvalume, with its exceptional resistance to corrosion, durability, heat reflectivity, and aesthetic versatility, has proven to be a highly advantageous option for a wide range of projects.

But it does have limitations. Awareness of these, such as susceptibility to oil canning, interactions with certain materials, and restrictions on use in specific environments, is crucial to making sure you get a commercial roof that lasts.

Now that you're familiar with the ins and outs of Galvalume, are you considering it for your next project? Don't hesitate to reach out to us at GIDEON. In a free, 30 minute consultation, we can provide you with customized guidance, so you get the job done right.