Purlin is widely regarded as one of c purlin and z purlin for structural C and Z purlins for industrial purposes. Purlins are used for roofing sheets in such areas that require strong and solid steel foundations for industrial construction. In simple terms, purlins are a type of steel beam that runs across the length of a roof structure and provides much-needed support. C purlin is at 90 degrees and appears in the form of the letters “C”. On the other hand, Z purlins below 90 degrees usually have the shape of the letter “Z”. Both are used consistently in all steel structures as they affect the overall stability of the structure.