Galvalume vs Galvanized vs Aluminum

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When deciding what material to purchase for your metal roof in Florida, you may have come across various options like steel, copper, aluminum, galvanized, and Galvalume. So what's the difference, and how do you know which one is right for you?

Weighing the pros and cons of Galvalume and galvanized roofing can certainly be confusing. And since installing a new roof can already be a costly and stressful process, we're eager to offer our expertise. We've created a helpful guide to walk you through choosing the right roofing material for your needs.

Why choose a metal roof in Florida?

Overall, the main advantage of using a metal roofing material in Florida and coastal regions is its ability to withstand harsh weather conditions, including wind, rain, and saltwater corrosion. However, each type of metal roofing material has its own unique advantages, and choosing the right material depends on factors such as budget, aesthetics, and performance requirements. A qualified manufacturer and supplier of different metal roofing types and materials can provide valuable advice for your particular project.

Galvalume vs Galvanized vs Aluminum

Here are three popular types of metal roofing materials in use today:

Galvanized Steel Roofing

Galvanized steel is a type of steel that has been coated with a layer of zinc to protect it from corrosion. The process of galvanization involves immersing the steel in a bath of molten zinc or applying a zinc coating through electroplating. The zinc coating acts as a sacrificial layer, meaning that it corrodes before the underlying steel, providing protection against rust and extending the lifespan of the steel. Galvanized steel is relatively low in cost compared to other corrosion-resistant materials, but may not last as long before showing signs of corrosion.

Galvalume Roofing

Galvalume is a steel-based roof coating type that includes aluminum, zinc, and silicon that is up to twice as resistant to corrosion as galvanized steel. Invented by Bethlehem Steel Construction Company in the early s, Galvalume coating is made by hot-dipping the metals onto steel coils to make them adhere to the material. The coating can remain with a plain mill finish or painted in a variety of colors. As one of the most popular roofing materials on the market today, it's impressively durable. It is a low-maintenance material that will last for at least 40 years, providing significant savings throughout its lifetime.

Aluminum Roofing

While Galvalume provides good corrosion resistance due to its zinc-aluminum alloy coating, aluminum roofing offers even greater resistance to corrosion. Aluminum is inherently resistant to rust and corrosion, making it an excellent choice for areas with high moisture or salt exposure, such as coastal regions. Both aluminum roofing and Galvalume have long lifespans, but aluminum is generally considered to have superior longevity.

Applications

Where Should Galvalume Roofing Be Used?

The main purpose of a Galvalume coating is to protect steel from oxidizing (rusting), which compromises the integrity of the material. It may be installed on a wall, building trim, or as an accent, especially in climates subject to hurricanes, humidity, extreme heat, or high rainfall or snowfall. Thanks to its corrosion-resistant properties, Galvalume is ideal for humid and hot environments, commercial buildings, residential homes, storage units, and more, making it an affordable, low maintenance roofing material choice in many areas of Florida.

Where Should Aluminum Roofing Be Used?

Aluminum is preferred to Galvanized or Galvalume steel in coastal areas, as the elemental metal is more resistant to saltwater-induced corrosion and rusting. Galvalume's zinc-aluminum coating cannot withstand prolonged exposure to significant volumes of salt commonly found in the air of coastal areas. Saltwater is highly corrosive, which can quickly degrade Galvalume roofing on properties along the coastline, near large bays, surf breaks, and marshes. Aluminum is also highly malleable and can be easily formed into various shapes, profiles, and designs that gives architects and homeowners more flexibility in creating customized roof designs. Galvalume, being a steel product, has some limitations in terms of formability and design options.

Where Should Galvanized Steel Roofing Be Used?

Galvanized metal roofing is better suited for dry climates, free of pooling water and salt air environments which limits its broad application in Florida. Galvanized or pre-galvanized materials or insulated metal panels are a preferred choice for lower value applications such as outbuildings or barns. As a rule, Galvalume is not ideal for buildings used to house or enclose livestock, as its aluminum and zinc coating reacts with the ammonia from livestock manure. Animal waste breaks down into ammonia gas, creating a highly aggressive and corrosive environment that can damage metal roofing and walls. Once the metal loses its protective coating, it will rust and corrode within a short time. If you choose to use this material for structures used for animal confinement, they must have adequate ventilation to reduce ammonia gas concentration and its corrosive effect on Galvalume.

What Does Self-Healing Mean for Galvalume?

Most steel roofing materials end up having some 'edge creep' near the edges where the panel was cut. Fortunately, Galvalume is 'self-healing,' meaning it eventually stops creeping and won't spread rust all over the panel. But galvanized steel is not self-healing'the edge creep rusting will only worsen over time. The combined self-healing and rust-resisting properties of zinc and aluminum ensure that the material remains structurally sound despite its exposed edges. Eliminate the risk of edge creep through hemming or touching up the bare spots with paint.

Metal Roofing Wear

Although the wear of metal roofing is vastly superior asphalt, over time it can exhibit some wear characteristics that you should know about.

• Oil Canning
  Oil canning refers to the visible waviness or distortion on the flat surface of a Galvalume, painted or aluminum metal panel. It is innate in light-gauge, cold-formed metal products, particularly those with wide flat areas. This issue is only cosmetic and won't impact the roof's strength, durability, performance, or lifespan. Oil canning doesn't indicate the quality or structural issues with the roof, so it's not considered a valid warranty claim as it won't affect material performance. However, it can impact the overall appearance of the structure.
• Scuff Risk
  On painted or unpainted metal materials including Gavalume and aluminum, it's important to know that its coating can scuff, leaving an exposed portion of the metal panel that ages and weathers faster due to the lack of a protective layer. While many prefer the performance of Kynar painted panels, it is a softer finish than our standard WeatherXL paint and can be more easily damaged by foot traffic and environmental wear factors. Since you cannot fix a scraped surface, you may have to replace the entire section. Scuffing can also occur after the material gets dented, so avoid surface damage by limiting foot traffic and minimizing pressure or weight on the panels. If you need to place a ladder against the roof, do so in a way that it won't scratch the surface.
• Galvalume May Not Pair with Certain Materials
  Although Galvalume is highly durable, using it alongside other construction materials can speed up the degradation process. When installed directly on bricks, concrete, treated lumber, or other metals like iron and copper, this material may corrode in response to an electrolyte, like water. For this reason, it's also important to use a compatible screw material on any metal roof. Plus, mortar and concrete are highly alkaline, making them corrosive to Galvalume. If left unchecked, rust and corrosion can cause the roofing structure to fail. When the design requires Galvalume with the materials mentioned above, take precautions to minimize the risk of corrosion.

Which Is Thicker'Galvanized or Galvalume?

Galvalume and galvanized steel are both made through a hot-dipping technique and have a similar thickness, which is usually around 1 millimeter. This thickness may vary slightly from one material to the next, but if the Galvalume and galvanized steel coating are of the same thickness, the Galvalume coating will usually last longer than the galvanized coating.

What Roofing Material Lasts the Longest?

As we've mentioned already, Galvalume tends to last almost twice as long as galvanized steel before it shows any signs of wear. This is mainly due to the aluminum that is added to the coating to prevent oxidation. Both Galvalume and aluminum roofing have long lifespans, but aluminum is generally considered to have superior longevity. Aluminum roofs can last for many decades without significant degradation, whereas Galvalume roofs typically have a slightly shorter lifespan. For the greatest lifespan, select stainless steel or aluminum roofing materials.

What Has a Better Warranty?

Virtually all aluminum and most Galvalume roofing materials come with a warranty because they're known for being durable and long-lasting. However, many galvanized materials do not have a warranty since they can be unpredictable and unreliable, especially once they begin to rust.

What Material is Most Affordable?

Because galvanized and Galvalume steel are made in a similar fashion, they're sold at a similar price, though some lower grades of galvanized steel are available for less expense. Aluminum roofing is a premium product that offers higher performance and lifetime, but also a higher cost. Metal roofing is often more expensive than asphalt shingles, but the long-lasting nature of the products means they are usually more cost-effective overall and save the homeowner money long term.

As we outline in our metal roofing cost guide, other factors also affect project pricing. Underlayment, complexity, and scope are some considerations that can weigh on the total cost. If you want to know how Galvalume compares to other roofing materials, request a quote from different roofers.

The Bottom Line

Here are the differences and advantages of each roofing material in Florida and coastal regions:

• Galvanized steel: Galvanized steel is coated with a layer of zinc to protect against corrosion. However in Florida, humidity and salt air can accelerate corrosion on galvanized steel so it's not recommended for long-term durability in residential applications. Its advantages include affordability, ease of installation and a classic look.
• Galvalume: Galvalume is a popular choice for many Florida regions because of its enhanced durability and ability to withstand corrosion better than galvanized steel. In addition, Galvalume roofing is generally less expensive than aluminum roofing. If cost is a primary consideration, Galvalume may be a more budget-friendly option.
• Aluminum: Aluminum is a premium lightweight metal that is inherently resistant to rust and corrosion. It is the preferred choice for coastal regions due to its higher resistance to saltwater corrosion and superior longevity. Other advantages include durability, low maintenance and higher energy efficiency due to its reflective surface.

Ultimately, a choice between Aluminum roofing vs Galvalume depends on factors such as the specific application, budget, desired aesthetics, and environmental conditions. Both materials offer corrosion resistance and durability, but aluminum roofing excels in terms of superior corrosion resistance, lighter weight, and enhanced thermal performance.

We can help

Choosing the right metal roofing materials can be overwhelming, but now that you know more about these types of roofs, you're better equipped to handle the big task of installing a new one.

Does Galvalume or Aluminum sound like the right choice for your next project? Contact 1st Coast Metal Roofing Supply to order your high-quality materials. We're happy to answer any of your questions about metal roofs and offer help you decide if you're still comparing Galvalume vs galvanized or aluminum roofs. Get in touch with us today for a free quote.

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About 1st Coast Metal Roofing Supply

Protect your home from Florida's extreme weather conditions with durable and reliable metal roofing solutions from 1st Coast Metal Roofing Supply. As the leading metal roofing manufacturer and supply company based in Florida, we offer a wide range of high-quality roofing materials that are designed to withstand hurricane-force winds, tropical rainfalls, and the harsh UV effects of intense sunlight. With our expert guidance and exceptional customer service, you can trust us to provide you with a roof that not only looks great but also lasts for years to come.

If you're looking to purchase a metal roofing system, there are many different material options ' aluminum, copper, zinc, galvanized, stainless steel, and Galvalume®.

The most widely used metal in architectural metal roofing is Galvalume, a steel-based product that can be used for nearly every building application. 

How much do you know about Galvalume? Do you know the critical advantages and disadvantages of this metal roofing material? 

Our primary product offerings at Sheffield Metals are painted and bare Galvalume coils and sheets used in the architecturally-driven metal roof and wall industry. We know how important it is for you to be an educated buyer, so let's dive into the specific details of this material and why it may or may not be a good choice for your project.

Additional reading:
How to Properly Paint Aluminum Coil for Insulation

If you are looking for more details, kindly visit Galvalume Steel Coil for modular houses.

Ahead in this article, we cover:

• What is Galvalume?
• Uses for Galvalume
• Advantages of Galvalume
• Disadvantages of Galvalume

What Is Galvalume®?

Bethlehem Steel introduced the Galvalume coating to the construction industry in the early s. Before Galvalume came into existence, most metal roofing was galvanized steel. However, because of the superior durability and corrosion resistance of Galvalume, 90+ percent of the metal roofing industry transitioned from galvanized substrates to a Galvalume substrate in the mid to late s.

Galvalume combines three of the most high-performing and important metals used in roofing today ' steel, aluminum, and zinc. Manufacturers begin with a cold-rolled carbon steel base sheet that is continuously hot-dipped with aluminum and zinc alloys (AZ) until it reaches a coating of 55% aluminum, 43.4% zinc, and 1.6% silicone. 

This process allows for one material to have some of the best characteristics of each metal, which is why it's become one of the most popular metals used in metal roofing.

Galvalume may also be referred to by its coating weights, AZ-50 and AZ-55. Here's a quick breakdown of what these two terms mean:

• AZ-50 = 0.50 ounces per square foot of the aluminum-zinc alloy coating applied to both sides of the substrate.
  • AZ-50 is the typical coating weight for painted sheet and coil products.

• AZ-55 = 0.55 ounces per square foot of the aluminum-zinc alloy coating applied to both sides of the substrate. 
  • AZ-55 is the typical coating weight for bare or unpainted (often called acrylic-coated Galvalume or Galvalume Plus) sheet and coil products.
  • Acrylic-coated Galvalume has a slightly heavier coating weight and includes a light acrylic coating that protects the Galvalume coating in the manufacturing process. This acrylic coating will wear off over time with exposure. Though not painted, these products still need to be handled with care, or you risk scuffing or perforating the coating.

Uses for Galvalume® Metal Roofs & Walls

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.

Some common uses for Galvalume include:

• Commercial buildings ' Hospitals, schools, stores, government buildings, and more
• Residential projects ' Single-family, multi-family, condominiums, and more
• Architectural structures ' Commercial, governmental, residential, and more
• Structural or industrial applications ' Warehouses, factories, and more
• Agricultural ' Non-animal confinement spaces, barns, storage, and more

However, there are some situations where Galvalume is not recommended for use. In most of these situations, the primary concern is that the aluminum-zinc coating will prematurely break down and cause the system to fail quicker than if it were not in that location. 

Here are a couple of circumstances where Galvalume should not be used:

• Animal enclosures or buildings ' Galvalume is not suitable for use on buildings where animals are housed or held. Manure from the animals breaks down into ammonia gas over time and then reacts with the Galvalume coating. This process breaks down the Galvalume coating and leads to degradation of the metal. However, Galvalume is sometimes used on modern chicken houses built with a vapor barrier between the chicken area and the roof for appropriate ventilation. It's best to check with the manufacturer before putting Galvalume on an animal confinement building, as it's often dependent on the specific design and use. 

• Coastal environments ' The coating of Galvalume will not stand up to the conditions associated with a coastal environment, including properties up against breaking surfs, large bays, marshes, and other coastlines. Specifically, large amounts of salt will degrade the Galvalume coating and lead to premature damage to the roof or wall. It's recommended that properties within a certain distance of a coast use an engineered aluminum roof system, as aluminum resists corrosion and rusting from saltwater for much longer.

If your project is in one of these environments or you're unsure if your location is corrosive to Galvalume, it's best to check with the manufacturer to see what they recommend.

Advantages & Benefits of Galvalume® Metal Roofing

Warrantied Product

One of the number one selling points of Galvalume is the 25.5-year warranty on the substrate, which is sometimes referred to as a perforation warranty. Galvalume systems also often come with paint warranties that further protect your investment and provide peace of mind that the roof or wall system will last. (Note: Substrate or paint warranties are NOT available for Galvalume products within 1,500 feet of a coast.)

Plus, commercial property owners can buy a weathertight warranty for their Galvalume roofing structure, which ensures the roof was installed correctly and adheres to strict installation details.

Corrosion Resistance & Self-Healing Properties

Galvalume's chemical formula was specifically designed to combine the toughness, strength, and self-healing properties of zinc with the rust resisting properties of aluminum. That's why Galvalume's corrosion resistance is about two to four times better than galvanized steel. 

Galvalume's self-healing characteristics help control the red rusting at any cut/exposed edges. Nearly all steel-based products will experience some level of normal edge creep from the exposed steel when the coil is cut, but it is minimal and will eventually stop with Galvalume. Remember that edge creep can also be offset by hemming the panels and touching up any exposed edges with paint pens.

Additionally, these self-healing characteristics make failure in the roof field less likely with Galvalume systems.

Easy to Handle & Install

Another benefit of Galvalume is that it's not as temperamental as other metals used in the roofing industry, like copper and zinc. Installers don't have to worry as much about leaving fingerprints, deep scratches, etc., on panels because Galvalume is tougher and a little more tolerable. It also doesn't have many strict ventilation or air gap requirements like some other metals. 

Plus, Galvalume is a standard metal roofing product and doesn't have too many special requirements, which allows the installation details to be pretty standard across the board. 

Even though it's a tough material, installers still find Galvalume easy to handle, rollform, cut, and beyond. 

Longevity

Research indicates that Galvalume roofing could last as long as 50+ years in the right environment without any extreme corrosion. This makes Galvalume an excellent choice for home and property owners looking to buy a roofing system that won't need to be replaced every 10-15 years, like asphalt shingles.

Economical & Competitively Priced

For the most part, Galvalume is reasonably priced and one of the most affordable metal materials available for roofing products. Depending upon the thickness, color, and quality of the desired Galvalume panels, pricing ranges anywhere from $5.00 to $15.00 per square foot. Keep in mind that in and , steel prices are continually fluctuating, so the price can vary dramatically.

Disadvantages & Cons of Galvalume®

Oil Canning 

Oil canning is an inherent characteristic of light-gauge, cold-formed metal products, especially products with broad flat areas. It is a visual phenomenon seen as waviness or distortion in the flat surfaces of metal panels. Luckily, oil canning is only an aesthetic concern that does not affect the strength or performance of the system. This occurrence is possible with any metal roof or wall type, including Galvalume. 

However, there are methods to minimize the appearance of oil canning, including:

• Purchasing a thicker sheet or coil product (22 vs. 24 vs. 26-gauge).
• Buying trustworthy brands of coils and sheets.
• Rollforming panels with striations or bead stiffeners in the flat area of panels to minimize the appearance of oil canning.
• Hiring an experienced contractor who knows the best material handling and installation practices that help reduce oil canning.
• Ensuring there are no roof decking issues, as the metal will follow any inconsistencies on the deck. So, if the roof deck is not in plane, consider fixing it beforehand to reduce the risk of oil canning.

Interactions with Other Materials 

Combining different metals on a metal roof system can lead to interactions that could result in early degradation, staining, and potential failure of a system altogether. 

Galvalume performs best when not in contact with copper, lead, bricks, treated lumber, iron, and concrete. If Galvalume is in contact with one of these and is then introduced to an electrolyte such as water, it can lead to galvanic corrosion of the metal.

Unpainted Galvalume Can Scuff Easier

One of the considerations that contractors should remember when installing non-painted Galvalume is that you can scuff off the acrylic coating in high-traffic areas. Once the coating is scuffed, there's not much that can be done to fix the issue other than immediately replacing the scuffed panels. If scuffed unpainted Galvalume is left on the roof, it may become splotchy as the scuffed/exposed parts of the roof age and weather quicker. 

When installing unpainted Galvalume, it's best to:

• Limit the foot traffic on newly installed panels.
• Be aware of ladder placement.
• Refrain from pivoting or pressing shoes/boots down too hard on the installed panels.

Final Thoughts on Galvalume® Metal Roofing

Galvalume is an excellent option for many metal roofing projects, but it's still important to know when it should and shouldn't be installed.

To recap what we've covered:

• Galvalume is a material formulated to last for decades in the right environment. 
• Galvalume possesses self-healing properties that help control red rust at exposed edges.
• Galvalume is easy to handle, tolerable, and doesn't have extensive special installation requirements.
• Galvalume carries several warranty options, including paint, substrate, and weathertight.
  • Note: Weathertight warranties are only available for commercial applications.
• Galvalume should not be used in coastal environments or on animal enclosure structures.

Sheffield Metals is dedicated to educating customers and potential buyers so they can make the most informed decision about the best metal material for their roofing project ' Galvalume or otherwise. Whether you're a contractor, architect, manufacturer, property owner, or beyond, we can work with you to choose the right product for your project(s).

Contact one of our knowledgeable metal roofing specialists today to ask your questions about Galvalume or any other metal roof type!

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