Purlins are non-pressure treated, 1” x 4” x 12' lumber that is installed on to the roof in a specific layout pattern and screw pattern.

What kind of wood is used for purlins?

Purlins: roof purlins are 2x4, 2x6 or 2x8 lumber that spans between the trusses to provide framing for metal roofing or roof sheathing. May be attached above the trusses on-edge or flat, or between the trusses using post frame anchors or joist hangers.

Can you put metal on treated wood?

Pressure treated wood does not work well with metal. The reaction to the chemicals in the wood and copper which is a dissimilar metal cause the metal to rust. It is recommended that you always use untreated pine or spruce stringers to attach the metal to.