Traditional Purlin Roof Construction

They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top.

Traditional purlin roof construction. 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. Purlin plate principal purlin and common purlin. Nowadays finding a traditional roof being constructed on a new building is quite difficult. The traditional option is steeply pitched rarely less than 35.

In traditional timber framing there are three basic types of purlin. The rafters are the main load bearing elements of the roof. By chance we came across this roof a few miles outside bristol. They span from the wallplate to the ridge board providing a platform for the underlay battens and tiles.

Sizes used in traditional roofing construction. Parts of a traditional queen post roof truss. In traditional timber truss construction purlins rest on the principal rafters of the truss. Building control guidance note purlin and rafter roofs timber sizes and construction details.

Roofs and not for traditional purlin and rafter roof construction. At the eaves and halfway between the two where they are known as purlins. Pitched roof construction. Once the purlins are in place the panels can be craned in in a matter of minutes.

They give added support to the roof and also provide a nailing surface for the end panels and drip edge. For example an 8 x 4 under purlin would support the center of a row of 6 x 2 rafters that in turn would support 3 x 2 roof purlins to which the roof cladding was fixed. It s an l shaped house with two very different roofs one is a collar roof the other a purlin roof with rsjs forming the purlins see photos below. There are three types of purlins in wood construction.

Metal roof purlins are installed horizontally under metal roofs. Purlins are 2 by 4 feet and are installed much like metal roofing. 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 roof support system is a ridgepole and either rafters which run perpendicular from the top of the walls to the ridge or purlins which run parallel to the ridge.

Purlin plates under purlin principal purlins and common purlins. A common arrangement is a rafter and purlin system which combines purlins and rafters. All the figures are based on roofing tiles or slates laid on. The longitudinal horizontal beam that is sitting on a post or the principal rafter of a truss and used to support common rafters.

Traditional or cut roof.