Purlin Roof Support

Purlins are 2 by 4 feet and are installed much like metal roofing.

Purlin roof support. 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. They give added support to the roof and also provide a nailing surface for the end panels and drip edge. When made of wood it is usually covered with some sort of weatherproofing and sometimes an insulation material. Purlin plates in wooden construction.

The term plate means a major horizontal supporting timber. A common arrangement is a rafter and purlin system which combines purlins and rafters. By supporting the rafters they allow longer spans than the rafters alone. A purlin plate in wood construction is also called an arcade plate in european english under purlin and principal purlin.

E purlin is an engineered lvl roof underpurlin to support stick roofs for tile and metal sheet cladding. Purlin plates are beams which support the mid span of rafters and are supported by posts. Several kinds of purlins exist. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top.

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. The purlins of a roof support the weight of the roof deck.