What is purlin

Purlin, also known as purlin and truss, is a horizontal roof beam perpendicular to the roof frame or rafter, which is used to support the rafter or roofing material. Purlin is a transverse bending (usually bi-directional bending) member, which is generally designed as a single-span, simple-support purlin. Commonly used purlins are solid web type and light steel joist type.

When the purlin span is less than or equal to 4 meters, it should be based on the calculation requirements to determine clearly whether the roof position needs to be installed tie. When the slope of the roof is greater than or equal to 1/10, or when the purlin span is greater than 4 meters, it is necessary to install a tie bar in the purlin span position and will be subjected to the edge position of the pressure wing. When the purlin span is more than 6 meters, it is better to install a tie bar at all three points of the purlin.