Florida Licensed Roofing Contractor — CCC1330718
Choosing between bare Galvalume and Kynar 500 PVDF coating for your Florida metal roof. Compare cost, durability, salt air performance, and UV resistance.
Metal Roof Finishes
When Florida homeowners choose a metal roof, the conversation almost always comes down to one decision: bare Galvalume versus Kynar 500 PVDF-coated metal. Both are excellent roofing materials with decades of proven performance in the harshest coastal environments in the United States. But they serve different priorities — one prioritizes raw corrosion resistance at a lower cost, the other adds a premium paint system with color flexibility and a 40-year warranty. Understanding the difference is essential before investing in a metal roof that will sit on your home for 40 to 70 years.
At Coastal Roofing and Waterproofing Inc., we install both Galvalume and Kynar 500 metal roofing systems throughout South Florida. Our Florida roofing license CCC1330718 means every installation is code-compliant, properly engineered for your wind zone, and backed by a contractor who has been working in Broward, Palm Beach, and Miami-Dade counties for over 25 years.
Galvalume is a steel substrate coated with an aluminum-zinc alloy — typically 55% aluminum, 43.5% zinc, and 1.5% silicon by weight. This coating is applied during the manufacturing process in a continuous hot-dip line, producing a sheet with a natural metallic finish that looks similar to a dull mill finish or light gray. There is no paint involved. The surface is the coating itself.
The key advantage of Galvalume is its self-healing property. When the surface is scratched or cut, the zinc component sacrificially protects the exposed steel, preventing rust from taking hold. The aluminum component forms a stable oxide barrier that slows further corrosion. In Florida's aggressive salt-air environment, Galvalume has been shown to outlast traditional galvanized (pure zinc) coatings by a factor of two to six times. ASTM A792 is the governing specification, and most Galvalume roofing carries an AZ50 coating weight as a minimum for exterior exposure.
Galvalume is also the least expensive metal roofing substrate available. Without the added cost of a factory-applied paint system, bare Galvalume panels can cost 15 to 30 percent less than their Kynar 500-painted counterparts. For homeowners who want the longevity and wind performance of a metal roof at the lowest possible price — and who are fine with a natural metallic appearance — Galvalume is an outstanding choice.
Kynar 500 is not a metal substrate — it is a paint resin system applied over a metal substrate (almost always Galvalume). Kynar 500 is a trade name for polyvinylidene fluoride (PVDF), a fluoropolymer resin that is widely considered the gold standard for architectural metal coatings. The coating is applied as a multi-layer system: a primer, a color coat, and often a clear topcoat, baked onto the metal at the factory.
The defining characteristic of Kynar 500 is its extraordinary resistance to ultraviolet degradation. In Florida, where UV intensity is among the highest in North America, lower-quality paints (polyester, acrylic, siliconized polyester) chalk, fade, and lose gloss within 5 to 10 years. Kynar 500 coatings retain 70 percent or more of their original color and gloss after 30+ years of Florida sun exposure. Most Kynar 500 paint systems carry a 40-year limited warranty covering chalk, fade, and film integrity.
Beyond UV performance, Kynar 500 offers a full color range — from charcoal gray and slate blue to brick red, forest green, and custom color matches for HOA requirements. This is something bare Galvalume simply cannot provide. If your homeowners association requires a specific roof color, or if you want your roof to complement your home's aesthetic, Kynar 500 is the answer.
Florida's climate creates a triple threat for metal roofing: salt air, intense UV, and extreme heat. Here is how Galvalume and Kynar 500 stack up:
Choose bare Galvalume if: You want the most cost-effective metal roofing option, prefer a natural metallic look, are not constrained by HOA color requirements, and want maximum corrosion resistance per dollar. Galvalume is popular on barns, workshops, and homes where a utilitarian aesthetic is acceptable or desirable.
Choose Kynar 500 if: Your HOA requires a specific color, you want to enhance curb appeal with a premium finish, you want a 40-year paint warranty against fade and chalk, or you want the best possible UV protection for a home that will be seen every day. Kynar 500 is the standard choice for residential metal roofs in planned communities and upscale neighborhoods.
As a general rule, Kynar 500-painted metal roofing costs 15 to 30 percent more than bare Galvalume for the same panel profile. On a typical 2,000-square-foot roof, that translates to a premium of roughly $3 to $7 per square foot of roof area, or $6,000 to $14,000 total. For many homeowners, the 40-year paint warranty and color flexibility justify that premium. For others, bare Galvalume's lower cost and proven coastal durability make it the smarter investment.
We install Metal Alliance metal roofing panels in both Galvalume and Kynar 500 finishes. Explore our available profiles:
When bare Galvalume panels are cut to length on site, the exposed steel edge has no protective coating. In coastal Florida, these cut edges are where rust starts first — often within 5-7 years. Kynar 500 coating is applied before forming, so it wraps around edges for full protection.
Most Florida HOAs require painted metal roofs in specific colors. Bare Galvalume's natural metallic gray rarely meets HOA architectural standards. Kynar 500 is available in 30+ colors, including matte black and charcoal — the most popular choices for upscale Florida communities.
We install 24ga Galvalume with Kynar 500 finish as our standard on every metal roof. We don't offer bare Galvalume — the 15-20% cost savings isn't worth the accelerated deterioration in Florida's climate.
FAQ
Both perform well in Florida's salt air. Galvalume's zinc-aluminum coating is self-healing and naturally corrosion-resistant, making it ideal for bare-metal coastal installations. Kynar 500 adds a PVDF paint layer over a Galvalume substrate, providing additional UV protection and color options. For homes within a few miles of the coast, either system is excellent — Galvalume for a natural metallic look, Kynar 500 for color and extended paint warranty.
Kynar 500 PVDF-coated metal roofing typically costs 15–30% more than bare Galvalume, depending on the panel profile and color selection. The premium buys you a 40-year paint warranty, full color range, and superior UV fade resistance. For homeowners who want a specific color or whose HOA requires it, Kynar 500 is worth the investment.
Galvalume does not rust like ordinary steel. Its aluminum-zinc alloy coating is sacrificial and self-healing — it continuously protects the underlying steel even if scratched. In Florida's coastal environments, Galvalume has been proven to outlast galvanized steel by 2–6x. It may develop a dull patina over time, but this is cosmetic, not structural corrosion.
Coastal Roofing and Waterproofing Inc. is committed to helping property owners make informed decisions about metal roofing systems. The following resources provide authoritative technical information on coatings, materials, and product specifications.
Every metal roof installed in Florida must meet FBC 8th Edition (2023) requirements. The roof system — panels, clips, underlayment, and fire barrier — must have a valid Florida Product Approval or Miami-Dade NOA. Here's what matters for your metal roof:
Metal roofs must withstand design wind pressures calculated per ASCE 7-22. In South Florida: 170 mph (Broward, Miami-Dade, PBC). In Southwest Florida: 140-150 mph (Naples, Fort Myers). Clip spacing is engineered per the product approval for your specific wind zone and mean roof height.
In Broward and Miami-Dade (HVHZ), metal roofs require a fire barrier between the deck and underlayment. We use Polyglass XFR fire barrier — 1 layer for 24ga Galvalume, 2 layers for aluminum stainless steel. Non-HVHZ zones (Palm Beach, Collier, Lee) do not require this layer.
FBC 706.7.2 requires a secondary water barrier on all full roof replacements with wood decks. We install self-adhered underlayment (Polyglass MTS or TU Max) directly to the clean deck. This provides waterproof protection even if panels are blown off in a hurricane.
FBC 706.7.1 requires 8d ring-shank nails (2-3/8" x 0.113") at 6" o.c. on all full replacements with wood decks. We re-nail every deck before installing underlayment — this is non-negotiable for code compliance and storm performance.
Metal Alliance Product Approvals: 100SL Standing Seam — FL29523 | 155SL Standing Seam — FL30780 | All systems HVHZ-rated for Broward & Miami-Dade
Whether you choose Galvalume or Kynar 500, Coastal Roofing and Waterproofing Inc. will engineer and install a system that lasts. Schedule your free inspection today.