Knit one, purlin two.
We’re learning a whole new vocabulary as the building rises….
A “column” is a primary, vertical beam.
A “girder” is a support beam.
A “girt” is a horizontal structure in a wall.
A “joist” is a horizontal structure that supports a ceiling, roof, or floor.
And a “purlin” is a horizontal structure in a roof.
![girt-web A wall girt.](https://ezidesignconcept.com/wp-content/uploads/2009/07/girt-web.jpg)
![roof-girder-web Installing a roof girder.](https://ezidesignconcept.com/wp-content/uploads/2009/07/roof-girder-web.jpg)
![roof-girder-2-web Close-up of roof girder installation. You can't have a fear of heights in this work!](https://ezidesignconcept.com/wp-content/uploads/2009/07/roof-girder-2-web.jpg)
![floor-joist-web Floor joists placed for later installation.](https://ezidesignconcept.com/wp-content/uploads/2009/07/floor-joist-web.jpg)
![floor-joists-2-web Mezzanine floor joists installed. The heavier beams are those below the life support system rooms.](https://ezidesignconcept.com/wp-content/uploads/2009/07/floor-joists-2-web.jpg)
![purlin-web And finally, the roof purlins!](https://ezidesignconcept.com/wp-content/uploads/2009/07/purlin-web.jpg)
![purlin-2-web Installing the purlins.](https://ezidesignconcept.com/wp-content/uploads/2009/07/purlin-2-web.jpg)
Many thanks to Mike Turcotte and his crew at H & S Construction for their patience in answering my structural steel questions. “What’s that beam called, and what’s it for?….” Wikipedia is to thank for concise definitions. Any errors in this post are mine!