ROOF SHEET

Metal roofing sheets are becoming more and more popular with their high durability and aesthetic beauty. AMC specializes in providing high quality roofing products with the most competitive prices.

Metal roofing and coatings

Metal roofing used in residential construction is mainly made of steel or aluminum. Copper, zinc and titanium are also used in some of the house, factory's signature architecture.
Roofing sheets were originally manufactured in long, thin boards, rolled into large rolls at steel mills. They are then coated with a metal coating to prevent rust, followed by a high-speed paint line and high-temperature firing. The painted steel coil is shipped to a roofing manufacturer, where it is shaped using a large press to stamp the sheet into distinct shapes such as corrugated, tile. 
Roofing aluminum also performs a similar process except that it does not need to go through a metal coating step. Roofing sheets used in residential construction are manufactured to the thickness specified by the gauge and usually 24 -26 gauge, the higher the gauge number, the thicker the roofing sheet. Corrugated or tile roofing is a special category and is manufactured by stamping galvanized steel (26 gauge) then spraying an acrylic coating and then fired in the furnace at the factory.

Metal coating
The entire surface of the roofing sheet is covered with a protective metal layer to prevent rust. It is inside and separate from the paint that gives the product its color. There are two types of metal coatings commonly used:– Galvanized: 100% zinc plated with varying thickness depending on product requirements.– Galvalume or Zincalume: An alloy of aluminum and zinc (55 %) aluminum and 45% zinc)
This metal coating protects the iron (Fe) in the roofing sheet from oxidation when exposed to air and moisture. Zinc is a more active metal than iron so it oxidizes first and forms a strong protective barrier of zinc oxide, before the iron (Fe) in steel can become iron oxide (rust). When zinc is combined with aluminum to form Galvalume it can provide better protection in most cases.
Thickness of metal coating
The thickness of the metal coating used in the roofing process varies depending on the actual application of the roofing sheet. In agricultural applications, a zinc coating of G-40 or G-60 can be effectively achieved. For houses, roofing should be at least G-90. The larger the coating, the longer the rust protection lasts.
No. G-40; G-60; and G-90 refer to ounces of zinc per 100 square feet of galvanized sheet (both top and bottom). The G-90 will have 90 ounces of zinc, which is 45 ounces per side of 100 square feet of corrugated iron. 
Salt in the environment
Aluminum roofing is often more effective when used on roof surfaces in environments that are exposed to a lot of salt, such as areas near the sea. In environments not exposed to salt salts, both Galvalume Galvanized and Galvanized will provide a protective layer that has a longer service life.
Paint system
Most metal roofing in residential construction has an exterior coating. Painted surfaces create the aesthetic beauty that consumers want to see on their roofs. It can also include both heat-resistant and energy-saving substances. The metal roofing coating process uses a very sophisticated coating technology. Roofing material is painted when it is in the form of flat sheets in large rolls. However, this coating is flexible enough to be stamped into specific shaped corrugated iron sheets such as corrugated or tiled shingles. The paint quality for roofing metal is evaluated to varying degrees. and they will affect the price of the product. Some paints retain their color over time, paint insulation, heat resistance, etc.