![cover image](https://wikiwandv2-19431.kxcdn.com/_next/image?url=https://upload.wikimedia.org/wikipedia/commons/thumb/a/a3/Common_Purlin_Highlighted.jpeg/640px-Common_Purlin_Highlighted.jpeg&w=640&q=50)
Purlin
Structural member in a roof / From Wikipedia, the free encyclopedia
Not to be confused with Perlin (disambiguation).
A purlin (or historically purline, purloyne, purling, perling) is a longitudinal, horizontal, structural member in a roof. In traditional timber framing there are three basic types of purlin: purlin plate, principal purlin, and common purlin.
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/a/a3/Common_Purlin_Highlighted.jpeg/640px-Common_Purlin_Highlighted.jpeg)
Purlins also appear in steel frame construction. Steel purlins may be painted or greased for protection from the environment.