White Rust on Galvanized Mesh – What Is It and Should You Worry?

If galvanized welded mesh develops a white, powdery substance on its surface, this is usually "white rust" — a form of zinc oxide or zinc hydroxide that forms when zinc reacts with moisture in a confined space. Unlike red rust, which actively eats into steel, white rust is primarily a surface phenomenon that doesn't immediately threaten the structural integrity of the mesh. White rust is most common on hot-dip galvanized material stored in damp, poorly ventilated conditions. If you see orange-brown rust spots that remain after cleaning, the zinc layer is compromised and the steel is corroding. For long-term use, proper storage and ventilation are just as important as the material itself.