Metal roof provides increased wind resistance when compared to other roofing materials. This is because metal roofing systems use interlocking panels. The disadvantages of metal roofs include the noise created from rain hitting the roof, and, in snowy areas, the tendency of snow to easily fall off the roof and onto pedestrians or property. Originally, metal roofs were made of corrugated galvanized steel: a wrought iron–steel sheet was coated with zinc and then roll-formed into corrugated sheets. Another approach is to blend zinc, aluminum, and silicon-coated steel. These products are sold under various trade names like "Zincalume" or "Galvalume". The surface may
Krakatau Steel chemically treated in Cold Rolling Mill becoming cold rolled coils and sheets. The results are generally used to manufacture car bodies, cans, cooking wares, and other applications. Billet steels are rolled in Wire Rod Mill to fabricate wire rods which are commonly used for piano wires, bolts and nuts, steel cords, springs, and other applications. Latest, PT Krakatau Nippon Steel Sumikin (KNSS) start operating its galvanized steel plant in Cilegon, Banten, in September 2017. KNSS, established in 2012, is a joint venture between NSSMC and state-owned steel maker PT Krakatau Steel to manufacture and market cold-rolled steel and hot-dipped galvanized