Traditional Purlin Roof Construction

Every member of a traditional cut roof is individually cut and assembled on site.

Traditional purlin roof construction.

There are three types of purlins in wood construction. In architecture or structural engineering or building a purlin or purline is a horizontal structural member in a roof. Parts of a traditional queen post roof truss. The beams will typically be placed along the ridge at the eaves and halfway between the two where they are known as purlins.

Traditional roofs work by distributing loads from the rafters down through to the wall plate and then through to the walls below. Once the purlins are in place the panels can be craned in in a matter of minutes. The best way to transfer load is with a timber to timber joint a compression fixing. There are two basic methods of pitched roof construction.

In architecture structural engineering or building a purlin is any longitudinal horizontal structural member in a roof except a type of framing with what is called a crown plate. Purlin plates under purlin principal purlins and common purlins. This is a large timber running at right angles to the rafters and usually positioned mid span. Sips panels these panels are from sipco need to be craned into place.

The use of purlins as opposed to closely spaced rafters is common in pre engineered metal building systems and both the ancient post and beam and newer pole building timber frame construction methodologies. Purlin plate principal purlin and common purlin. Nails bolts and screws create a mechanical fixing to stop uplift through wind etc. In traditional timber framing there are three basic types of purlin.

Exposed rafters are a feature of some traditional roof styles. It is a very common form of construction. The overall construction of a traditional cut roof is to ensure that the load of the roof is evenly transmitted to the walls below. The longitudinal horizontal beam that is sitting on a post or the principal rafter of a truss and used to support common rafters.

Purlins support the loads from the roof deck or sheathing and are supported by the principal rafters and or the building walls steel beams etc. In traditional construction spans of over 3 metres or so were often dealt with by adding a purlin. A truss roof using factory made trusses which are delivered to site complete and just erected. They span from the wallplate to the ridge board providing a platform for the underlay battens and tiles.

3 lean to roofs less common. The rafters are the main load bearing elements of the roof. Purlin in architecture structural engineering or building a purlin or historically purline purloyne purling perling is any longitudinal horizontal structural member in a roof except a type of framing with what is called a crown plate.