1. Profile – depends on your favorite, there are many types, styles, color and patterns

2. Thickness – base metal sheet which mostly uses with roofing has the thickness at 0.3 – 0.7 mm, but in the project standard it will be specified the Base Metal Thickness (BMT) at 0.42 mm. If it coated steel base with Aluzinc/Zincalume (coating AZ150), the total thickness will be 0.47 mm. If it coated with pre painted coated, the TCT will be 0.50 mm. So, you need to specify the right thickness, just a little different in thickness can affect to the strength of profile ability. In the middle to low-end market, it mostly uses the less thickness and thinner coating because it will be cheaper

Metal Sheet Specification, you can read more information from these articles "The Steel Roof, an Interesting Choice" and "Which roof profile is suit for the factory?"

3. Material Specification

3.1 Strength of Steel – In the most project, it will specify the Strength of Steel G550 (550 MPa, High strength of steel) but not much finding G300
3.2 Corrosion Resistant – It is affected to steel material warranty which indicating the long lifetime, so the customer should ask for the warranty certificate from the metal sheet manufacturer
In project standard, it will specify unpainted Aluzinc/Zincalume coating with (Aluminum Zinc Alloy-coated steel) 150 gram per square meter (AZ150) which has maximum 20 years warranty. In the case of Colorbond/Colornexgen pre painted coated steel, it is the high-quality color coating on the Aluzinc/Zincalume coated steel which has the maximum 30 years warranty

• In the middle level to low-end market, it will use the thinner coating which is 70-100 gram per square meter. The warranty year will be lower to 5-10 years accordingly
• The Galvanize/zinc coated steel using for site camp will have the thinner layer which lower than 70 grams per square meter, so it is so cheap

3.3 Material Quality - standard – There are various steels nowadays both imported and in-house steel, so don’t forget to check the TIS standard of the cold rolled steel. If it is the Zincalume coated steel, it will be referred to TIS standard 2228 and TIS standard 2753 for the pre painted color coated steel. In the project standard, it will also refer to the international standards such as Australian Standard AS, Japanese Standard JIS, European Standard or American Standard etc.

Please consider the main 6 points as mentioned above to get the qualified steel roofing with reasonable price making the building lasting for many decades by getting the strong roof to protect the building from sunlight, rain, and wind, and also having the engineering safety and look nice.

Be aware of what you choose, you might not know the equality of the product by just taking a look. Therefore, don’t forget to check the necessary specifications from the manufacturer before buying. We will give you the price in deep details in the following article because there are various roofing systems such as the width and height of the roof profile, the quantity roof sheets per area, and the installation equipment.