What is the purpose of a purlin in construction?

A purlin is a vital structural component used in the construction of roofs, particularly in buildings with metal or timber frame construction. Its primary purpose is to support long rafters between trusses, thus helping to distribute the weight of the roof framing and the roofing material evenly. By providing this lateral support to the rafters, purlins enhance the overall stability and strength of the roof structure.

In addition to supporting rafters, purlins play a crucial role in ensuring that the roof can effectively handle various loads, such as snow, wind, and other environmental factors. This makes them essential for maintaining the integrity of the building over time. The arrangement and spacing of purlins are designed based on the specific requirements of the structure, contributing to both the safety and resilience of the roof system.