Material specification for the base metal is highly detailed for projects, moving beyond simple steel or aluminum classification to defining the strength and coating weight precisely. Structural steel grades like G550 (minimum yield stress of 550 $\text{N}/\text{mm}^{2}$) or G300 are commonly specified to provide the necessary tensile strength for wide purlin spacing and wind load re... https://kkroofspecialist.com.sg/metal-roofing-singapore/