The service life of hot-dip galvanised steel depends primarily on the environment. In a rural or semi-rural environment with low pollution and low humidity, a standard structural galvanised coating (45–55 microns) will typically provide corrosion protection for 70–80 years before first maintenance is required. In an urban or industrial environment with higher pollution levels, service life is typically 40–60 years. In a coastal or marine environment (within 1km of the sea), service life reduces to approximately 20–30 years. In all cases, galvanised steel significantly outlasts untreated or painted mild steel equivalents — making it the most cost-effective long-term choice for outdoor structural applications.
