Corrugated Galvanized Zinc Roofing Sheet,as with almost any product the finish of the galvanized metal finish will change over time. After a period of time, the surface will appear to have a white oxide look. When this happens the material is actually protecting itself from further damage. We stock and sell several corrugated and decking panels in either a (G-60) or (G-90) level of galvanizing.We can produce special specifications of steel products according to orders.Our production process strictly conforms to the international standard of DIN/ASTM/AISI /JIS/BS to ensure the quality.