When color coating and galvanized steel are used together, the corrosion control provided is better than that of any system used alone. Galvanized coating protects the basic steel and provides cathodic and barrier protection. The color coating slows down the consumption rate of zinc and greatly prolongs the service life of galvanized steel.

Once the color coating is weathered or damaged. zinc pro­vides cathodic and barrier protection against paint stripping and rust. Because of this synergistic effect, it provides 1.5 to 2.5 times longer corrosion protection than zinc and color coat­ings used alone.