# Purlin

> Glossary term · [DutchGreenhouses glossary](/glossary.md)

A purlin is a horizontal roof member spanning between frames in general steel building construction. A Venlo greenhouse roof has none: its only horizontal members are the aluminium gutter and ridge, with the glazing bars running vertically between them, and its horizontal steel is the facade girts.

## See also
https://en.wikipedia.org/wiki/Purlin