Traditional Purlin Roof Construction

In traditional timber framing there are three basic types of purlin.

Traditional purlin roof construction.

This house s roof construction used prefabricated trusses from turner timber. By chance we came across this roof a few miles outside bristol. The rafters are the main load bearing elements of the roof. There are two basic methods of pitched roof 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. There are three types of purlins in wood construction. They span from the wallplate to the ridge board providing a platform for the underlay battens and tiles. Pitched roof construction.

Purlin roofs and prefabricated roofs are the two common forms of roof structures. The longitudinal horizontal beam that is sitting on a post or the principal rafter of a truss and used to support common rafters. Here insulation is usually placed between the roof joists i e. Purlin plates under purlin principal purlins and common purlins.

All the figures are based on roofing tiles or slates laid on. Building control guidance note purlin and rafter roofs timber sizes and construction details. 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. The traditional option is steeply pitched rarely less than 35.

The alternative construction is the traditional cold deck. Once the purlins are in place the panels can be craned in in a matter of minutes. At the eaves and halfway between the two where they are known as purlins. Sizes used in traditional roofing construction.

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. They also provide a speedy construction reduce onsite labour and costs and are most importantly versatile and provide a form of flexibility as they tend to have the capacity for a wide range of roof coverings. Roofs and not for traditional purlin and rafter roof construction. Parts of a traditional queen post roof truss.

Nowadays finding a traditional roof being constructed on a new building is quite difficult. Traditional or cut roof. A cut roof this is the traditional method of cutting the timber on site and building up the roof using rafters ridge boards joists and purlins etc the exact details being determined by the size of roof size of timbers etc. Purlin plate principal purlin and common purlin.