When specifying metal benches for coastal urban areas, the finish isn't just about aesthetics—it's a critical defense against a relentless enemy: salt-laden air. The most durable and recommended finish for this harsh environment is a multi-layer system, typically starting with hot-dip galvanizing followed by a marine-grade powder coating.
Hot-dip galvanizing involves immersing the steel bench frame in molten zinc, creating a metallurgical bond that provides sacrificial cathodic protection. Even if scratched, the zinc corrodes first, protecting the underlying steel. This should be the mandatory first step.
For the topcoat, a high-quality polyester or fluoropolymer powder coating formulated for marine environments is superior to liquid paint. It creates a thicker, more uniform, and chemically resistant barrier. Look for coatings certified to withstand 3,000+ hours of salt spray testing (ASTM B117). The color should be a medium tone; very dark colors absorb too much heat, which can accelerate coating breakdown.
While stainless steel (Grade 316) is excellent, its cost is often prohibitive for public projects. Standard painted finishes, even "outdoor" varieties, will fail quickly, leading to rust and frequent, costly maintenance.
The winning combination is galvanized steel + marine powder coat. This system offers decades of durability, minimal upkeep, and maintains a vibrant, welcoming appearance for your coastal public space, resisting corrosion, UV fading, and physical abrasion from constant use. Always request material samples and manufacturer warranty specifications for coastal exposure before purchasing.