Timber Roof Purlins

They meet at the top of the gable at a ridge beam which has extra bracing to attach it to the rafters.

Timber roof purlins.

There is an available purlin for every type of roofing material including purlin span for metal roof which is the most common material type to use this item. It is a horizontal bar that used to support building at the roof structurally. In lightweight timber roof construction under purlins were used to support rafters over longer spans than the rafters alone could span. The rafters are the beams of wood angled upward from the ground.

They give added support to the roof and also provide a nailing surface for the end panels and drip edge. Under purlins were typically propped off internal walls. 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. Purlins are installed horizontally under metal roofs.

This is a very traditional concept in heavy timber roof framing. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. Purlins are a series of horizontal timbers laid across or connected to as depicted above the principal rafters and support the roof covering typically 2 6 tongue and groove boards conventional or structural insulated panels sips and roofing. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to.

Purlin is a well known material in the field of architecture structural building or structural engineering. From this shot it appears that there are three purlins on either side of the roof.