When building homes, most western world countries all recognize the various ceramic and terracotta tiled roofing materials. However, there is a much more convenient, easier to install, maintain and apply material and that is galvanized steel in all its various forms.

Just to remove any doubt, PPGI is galvanized steel, it is pre-painted, which means that the product comes with a factor pre-painted surface that is more durable and reliant than a plain galvanized steel roof, which, even when painted by hand, will underperform against corrosion.

Galvanized steel coil material

Galvanized Steel Coil/Sheet (GI) are produced in a vertical or linear production process. Full Hard sheet metal is passed through an acid washing process, then transferred and rolled into a prefabricated form.

From this prefabricated form are three divergences, the first is a standard galvanized steel sheet, rolled and sold to roofing companies. The second version is a zinc plating process, where the sheet metal is passed through a zinc pot, which applies a thin zinc film to the surface of the metal. The third version is when the zinc is then covered by a coat of paint, both sides get painted which is added to improve corrosion resistance as well as provide a more aesthetic look.


In general, the material used to produce the metal is a steel alloy, the most popular alloys for roofing are CGCC, DX51D, Q195, Q235. The width of the coil ranges between 600-1250 mm, and the material thickness comes in different grades, ranging from 0.13-0.8 mm. If the PPGI materials have a zinc coat, that coat has a thickness of around 20-120g/m2. An average full coil of roofing steel weighing around 3-8 tons

Post Processing

After the initial metal has been formed into large coils, these coils are processed and classified by a range termed as zero spangle or extra smooth, which is dependent on which surface treatment the metal undergoes before it is either formed or further coated.

Once the material has been fully coated, it is bundled up into coils and distributed to metal forming companies that specialize in cutting and forming the coils into various popular roofing shapes and sheet dimensions.

Advantages of Metal Roofing

While many do not rate steel as a good solution, it is, in fact, one of the best roofing solutions on the market for a number of reasons. These include a long-life expectancy when properly installed. They will totally waterproof a house, as well as shed snow and ice. They are fire resistant, and also resistant to mildew, fungus, and insects.

Metal roofing is extremely light when compared to other materials, on average a metal roof will weigh between 50 to 150 lbs per square foot in comparison to 750 to 900 lbs per square foot of ceramics. This means that structurally, there is less weight on the support beams and foundations.


Metal sheeting is easy to install, provides a perfect barrier between the house and the elements and when insulated properly will provide great thermal insulation properties for both heat and cold, and they are significantly cheaper and easier to design, form and color than any other material.