Coastal Adelaide salt exposure can corrode standard Colorbond Zincalume substrate within 5-10 years. Marine-grade specification extends life dramatically.
Marine-grade Colorbond
Colorbond Coastline is specifically warranted for coastal exposure. AZ200 substrate vs standard AZ150, plus a thicker top coat. Cost premium of ~5-8% over standard Colorbond.
Stainless fasteners
Galvanised fasteners corrode in salt environments within 8-12 years. Stainless steel (Grade 316) fasteners extend life to 20-25 years. Specify on every quote.
Frame considerations
Galvanised steel frame is generally fine in metro coastal exposure with paint topcoat. For directly beach-facing properties, consider hot-dip galvanised + painted finish.