Coastal Corrosion

The Corrosion Zone

Salt is invisible but deadly to metal. The closer you build to water, the faster things rust. Watch how distance from the ocean changes what materials you need for your Florida Keys project.

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Distance from Water
0 ft
Corrosion Risk
Severe

Corrosion Zones Explained

Florida Building Code defines specific requirements based on distance from saltwater. Here is what you need to know for each zone.

Severe Zone 0-1,000 ft
  • 316 stainless steel fasteners required
  • Marine-grade aluminum or stainless connectors
  • Maximum corrosion protection coatings
  • Annual inspection recommended
  • No standard galvanized hardware allowed
Moderate Zone 1,000-3,000 ft
  • 304 stainless or hot-dipped galvanized
  • G185 galvanized connectors minimum
  • Protective coatings on exposed metal
  • Bi-annual inspection recommended
  • Dissimilar metal contact must be isolated
Standard Zone 3,000+ ft
  • Hot-dipped galvanized acceptable
  • Standard G90 connectors allowed
  • Basic protective coatings
  • Standard inspection schedule
  • Note: Rare in the Florida Keys

Distance Matters

Drag the slider to see how requirements change as you move closer to or farther from saltwater.

Distance from Saltwater 500 ft

Florida Keys Reality: Most locations in Monroe County are within 1,000 feet of saltwater on at least one side. The Keys are narrow, so you are almost always in the severe or moderate corrosion zone.

Required Materials
Zone Classification Severe
Fastener Type 316 Stainless
Connector Standard Marine Grade
Inspection Cycle Annual
Cost Factor 2.5x standard

Material Corrosion Resistance

Not all metals handle salt spray equally. Choose the right material for your location.

SS
316 Stainless Steel
Best choice. Marine-grade with molybdenum for maximum corrosion resistance.
SS
304 Stainless Steel
Good choice. Works for moderate zones. Less expensive than 316.
HDG
Hot-Dip Galvanized
OK for 1,000+ ft from water. Coating thickness matters. G185 minimum.
Cu
Silicon Bronze
Excellent for wood connections. Traditional marine fastener material.
G90
Standard Galvanized
Not recommended for Keys. Will fail prematurely in salt spray environment.
Fe
Uncoated Steel
Never use in Keys. Will rust through in months, not years.

Salt Spray Questions

Common questions about corrosion protection in the Florida Keys.

The salt spray zone is the area near saltwater where airborne salt particles can reach and corrode building materials. In the Florida Keys, nearly everything is in the salt spray zone since most locations are within 3,000 feet of saltwater on at least one side. The narrow Keys geography means salt spray comes from multiple directions, making corrosion protection essential for all construction.
Within 3,000 feet of saltwater, Florida Building Code requires stainless steel or hot-dipped galvanized fasteners and connectors. Standard galvanized hardware is not sufficient. The closer to water, the more corrosion-resistant your materials need to be. Within 1,000 feet, 316 stainless steel is strongly recommended. Between 1,000 and 3,000 feet, 304 stainless or heavy galvanizing (G185) may be acceptable.
Salt spray does not directly change wind load numbers, but it affects how you achieve those loads. Corroded connections lose strength over time, so you need materials that maintain their rated capacity in corrosive environments. A connector that rusts through cannot resist the loads it was designed for. Your wind load design is only as good as the materials that stay intact over time.
Florida Building Code specifies 3,000 feet from saltwater as the salt spray zone boundary. Within this zone, enhanced corrosion protection is required for metal fasteners and connectors. In the Keys, since most areas are surrounded by water, you should assume everything needs corrosion-resistant hardware. Even if one side of a lot is 4,000 feet from the Atlantic, it might be only 500 feet from a bay or channel.

Get the Right Materials Specified

Ensure your Florida Keys project uses corrosion-resistant materials that will last.

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Corrosion Facts
Zone Boundary 3,000 ft
Severe Zone 0-1,000 ft
Best Material 316 SS