Galvalume metal roof near the ocean
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January 7, 2026 at 7:49 p.m.
HannahFord7
Paul from Massachusetts asks: I live 3 miles from the ocean. Is it safe to install a Galvalume metal roof with a Kynar 500 PVDF coating? Or should I install an aluminum roof?
January 7, 2026 at 7:50 p.m.
HannahFord7
Hello Paul,
Below is what our roofing expert Scott Olsen with Pinnacle Roofing and Skylights had to say in response to your question:
Metal roofs installed near the coast face different elements than inland roofs. While metal roofs have long lasting paint systems, the primary concern is the potential for salt air corrosion to the metal substrate. It is important to compare both the substrate and paint warranties and look specifically at the Proximity to the Ocean Clauses, as various manufactures will specify distance from the ocean that may alter their warranty. Lastly, consider the quality of the installer, as unfinished edges and/or scratches to the metal will be susceptible to corrosion. Ultimately, aluminum is the safest choice, but also may have a higher cost.
Many times manufactures will provide information on their website such as this blog post:
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January 7, 2026 at 7:50 p.m.
HannahFord7
Hello Paul,
Below is what our roofing expert John Kenney with Cotney Consulting Grouphad to say in response to your question:
Paul, living near the ocean, changes how I would spec your metal roof. Salt-laden air dramatically accelerates corrosion, and not all metals — even when coated — perform equally in that environment. Your instinct to compare Galvalume with a quality Kynar (PVDF) finish versus aluminum is the right place to start.
Galvalume (steel coated with an aluminum-zinc alloy) has much better corrosion resistance than galvanized steel, thanks to the aluminum content and the “self-healing” edge protection built into the alloy. It’s a strong, durable substrate for standing seam roofs and, when painted with a high-quality PVDF finish such as Kynar 500®/Hylar 5000®, it offers excellent resistance to UV exposure, chalking, and atmospheric corrosion, provided the finish remains intact. PVDF coatings are widely used and backed by long-term warranties because they protect both appearance and film integrity over decades.
However, most manufacturers and industry guidance caution that Galvalume isn’t the best choice in direct saltwater exposure unless exceptional engineering and coatings are used. Many standard Galvalume products are not warranted for heavy salt-air environments (typically within about 1,000–1,500 feet of the shoreline), and the steel substrate can still corrode-creep at cut edges or where coatings are damaged — especially if salt spray frequently reaches the roof.
In contrast, aluminum roofing is naturally resistant to rust because it forms a passive oxide layer that resists salt-air corrosion even without heavy coatings. That makes aluminum one of the best choices for coastal environments — it’s often specified within a few miles of the ocean because it won’t develop red rust the way steel-based products can, even with good coatings. When finished with a premium PVDF paint, aluminum standing-seam roofs offer durability, low maintenance, and strong warranty coverage in seaside conditions.
So what should you choose?
- If your property is within about a mile or two of active salt air, aluminum with a high-quality PVDF finish (like Kynar 500) is generally the safer, longer-lasting choice because of its inherent corrosion resistance.
- If you’re farther inland (several miles from direct salt spray) and want a more cost-effective steel option, Galvalume with a quality PVDF finish can still perform well — but confirm with the specific manufacturer that the product and warranty apply in your environment.
Manufacturer/technical tip: Always verify with your material supplier or the metal roofing manufacturer what their coating warranty covers in coastal exposures. Many metal manufacturers offer coastal-grade or enhanced coatings designed for salt-air service, but they often require specific substrate weights (e.g., AZ60 Galvalume), sealed edges, and proper panel-finish systems.
Bottom line: Don’t install standard steel-based Galvalume in areas of intense ocean exposure unless the product, the finished coating, and the warranty are explicitly rated for that condition. Aluminum standing seam with a premium PVDF coating is usually the better long-term choice near the ocean. Lastly, the specifics I provided above are based on industry experience and recommendations from metal manufacturers and metal industry associations.
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