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Posted by McElroy Metal ● Nov 19, 2020 7:41 AM

Is Galvalume as effective as aluminum in coastal applications?

As one of the most challenging hurricane seasons on record comes to a close, we’re seeing a pattern. With costs and repetitive damage spiraling out of control, coastal building owners are looking for different solutions. While historically using aluminum panels along the coast was a given, frustrated building owners have begun asking with increasing frequency if Galvalume® panels can be effective for their coastal applications.

coastal_galvalumeWhile we’d love to answer that question with a resounding yes, unfortunately it’s not that simple. There are four main differences between Galvalume and aluminum panels. Ultimately the choice comes down to budget and expected performance. In order to help you make the best decision, let’s take a closer look at Galvalume and the main differences between it and aluminum.

What is Galvalume?

Galvalume-Sheet-Mar-Rural-sizedGalvalume, invented by Bethlehem Steel in 1972, is a steel sheet with a coating of 55% aluminum and 45% zinc. Galvalume is well respected for combining the excellent barrier corrosion protection of aluminum with the galvanic protection of zinc. Consequently, a 25 year substrate warranty is routinely offered on Galvalume materials.

For owners considering a painted product, it's important to realize that Galvalume uses the same paint systems and consequently offers the same finish warranties as aluminum.  And for the budget savvy owner, Galvalume can be supplied without paint making it even more affordable without compromising longevity. 

Given these reasons, it should come as no surprise that Galvalume has enjoyed a position of market dominance in the industry for the last 50 years.  In fact, leading metal panel manufacturers routinely embrace it as their preferred substrate for most applications.  


Under normal atmospheric conditions, Galvalume substrates offer a 25 year warranty and aluminum substrates offer no warranty. So if you want a warranty (and many owners do!) you might think it’s Galvalume for the obvious win. But what many folks don’t realize is that even Galvalume warranties exclude structures within 1500’ of the coast. While neither product carries a substrate warranty for these true coastal applications, historically most would give aluminum the win on longevity; however, since by nature Galvalume coatings are 55% aluminum, the in-field performance is far closer than you might think.


Aluminum substrates are 80-100% more expensive than Galvalume substrates. That’s serious money to any building owner. These considerable cost savings coupled with Galvalume's coastal performance are just two of the reasons more and more coastal owners are giving Galvalume products serious consideration in lieu of aluminum.

Strength/Uplift Values

In addition to being far more economical, Galvalume is also stronger than aluminum. By nature, aluminum is a softer material and as a result, simply can’t perform to the extreme wind speeds and uplift values that mother nature continues to throw at projects along the coast.

In fact, as both the frequency and strength of tropical storms continue to increase, many exhausted building owners are starting to put a greater emphasis on using the strongest panels (Galvalume) instead of those that might last a few years longer (aluminum). And when going head to head with mother nature, it’s hard to blame their logic.

Check out the video below showing a Large Missile Impact test. These types of tests simulate the effects of flying debris during high wind events, such as hurricanes.



Another discernable difference between aluminum and Galvalume substrates in the amount of expansion and contraction that the panels experience over the life of the building. This phenomena, also known as thermal cycling, occurs when the panels expand in warmer temps and contract in cooler ones. As you might expect, the results are much more dramatic on longer panel runs such as those for large commercial structures and tend to be a moot point for residential projects with shorter panel runs. Thermal cycling is a normal phenomena and an important consideration during building design.

Both steel and aluminum panels experience this condition however, aluminum panels expand and contract at a much greater rate than Galvalume panels. As long as it’s planned for in the building design, expansion/contraction factors are a non-issue in a comparison between Galvalume and aluminum; however, when the greater expansion/contraction factor isn’t taken into account for aluminum, the pressures caused by the unsupported thermal cycling can result in total roofing failure.

  Aluminum Galvalume®
Longevity X  
Price   X
Strength/Uplift Values   X
Expansion/Contraction Neutral if properly designed Neutral if properly designed


In summary, when asked if Galvalume is as effective as aluminum in coastal applications, there is no resounding right answer for everyone. The project specifics along with the owners performance expectations and goals all affect the decision. With that said, are we seeing a trend? The answer to that question is a resounding yes!

Based on several decades of acceptable performance, the cost savings and increased material uplift values using Galvalume over aluminum is a topic for serious consideration by many building owners.

If you’d like to discuss your specific project, Contact Us, we’re here to help.

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About McElroy Metal

Since 1963, McElroy Metal has served the construction industry with quality products and excellent customer service. The employee-owned components manufacturer is headquartered in Bossier City, La., and has 14 manufacturing facilities across the United States. Quality, service and performance have been the cornerstone of McElroy Metal’s business philosophy and have contributed to the success of the company through the years. As a preferred service provider, these values will continue to be at the forefront of McElroy Metal’s model along with a strong focus on the customer.

Topics: FAQ, Substrates and Coatings, Architect Resources

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