Purlins On A Roof

In structural steel or aluminum construction p urlins usually w shapes or channels transfer roof loads to the major structural elements supporting the roof.

Purlins on a roof. 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. By supporting the rafters they allow longer spans than the rafters alone. When made of wood it is usually covered with some sort of weatherproofing and sometimes an insulation material. Purlin plates are beams which support the mid span of rafters and are supported by posts.

Metal building roof purlins provide three structural functions. The wider the roofing panels the greater spacing distance you should put. There is a chance of damaging roofing sheets if you are failed to do so. A purlin plate in wood construction is also called an arcade plate in european english under purlin and principal purlin.

The purpose of purlins. Metal roof purlins are installed horizontally under metal roofs. A traditional purlin strictly by definition is a horizontal structural member in a roof. 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.

The term plate means a major horizontal supporting timber. A common arrangement is a rafter and purlin system which combines purlins and rafters. Purlins traditionally support the roof deck cladding sheeting and are in turn supported by the principal rafters steel beams etc. These structural supports run perpendicular across the rafter beams.

They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to. Purlin plates in wooden construction. Purlins are 2 by 4 feet and are installed much like metal roofing.

The metal roof purlins spacing must be done correctly within narrow tolerances. In the past the majority of roof structures were of wooden construction but over the past 15 to 20 years there has been. The purlins of a roof support the weight of the roof deck. The width of metal panels will determine the rafter spacing.

The type and spacing of purlins is a design consideration which depends upon the incident roof loads as well as the limiting lengths of sheeting to be used. The roof deck is the wood panel ply board or metal sheeting that creates the surface of the roof.