Timber Roof Purlins

From this shot it appears that there are three purlins on either side of the roof.

Timber roof purlins.

Under purlins were typically propped off internal walls. 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. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to.

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. This is a very traditional concept in heavy timber roof framing. It is a horizontal bar that used to support building at the roof structurally. 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.

Purlins are installed horizontally under metal roofs. Purlins are 2 by 4 feet and are installed much like metal roofing. 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. Purlin is a well known material in the field of architecture structural building or structural engineering.

They give added support to the roof and also provide a nailing surface for the end panels and drip edge. The purlins are the large beams perpendicular to the rafters.