ZINC coated iron is KNOWN as 'galvanized iron'. This soft iron sheet is popularly known as G.I sheets. The zinc coating RESISTS corrosion and improves the appearance of the METAL and permit it to be soldered with greater ease.These are also widely used, these are stronger than AC Sheets, However, because of HIGHER costs, these are replaced by AC sheets. These are not used for slopes flatter than 1 in 4.