What is purlin and rafter?
Purlin is a horizontal beam or bar used for structural support in structures, most often below the roof. Purlins are supported either by the building’s rafters or its walls. These are most commonly used in metal buildings, but in wood-frame structures, these also replace closely packed rafters.
What is a rafter in construction?
A rafter is one of a series of sloped structural members such as wooden beams that extend from the ridge or hip to the wall plate, downslope perimeter or eave, and that are designed to support the roof shingles, roof deck and its associated loads. A pair of rafters is called a couple.
Are purlins structural?
In architecture or structural engineering or building, a purlin (or purline) is a horizontal structural member in a roof. 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.
What is a purlin in construction?
In steel construction, the term purlin typically refers to roof framing members that span parallel to the building eave, and support the roof decking or sheeting. Purlins are most commonly used in Metal Building Systems, where Z-shapes are utilized in a manner that allows flexural continuity between spans.
What is rafter framing?
Rafters are long wooden boards used for the frame of the roof, also known as stick framing. Rafters are made on the job site by the roofers and they are typically cut into 2×10 or 2×12 beams, which slope down from the peak of the roof. Ceiling joists then help secure the rafters and the exterior walls.
What is the difference between girder and Girt?
is that girder is a beam of steel, wood, or reinforced concrete, used as a main horizontal support in a building or structure while girt is a horizontal structural member of post and beam architecture, typically attached to bridge two or more vertical members such as corner posts.
What is a building purlin?
In steel construction, the term purlin typically refers to roof framing members that span parallel to the building eave, and support the roof decking or sheeting. The purlins are in turn supported by rafters or walls.
Which is better a purlin roof or a rafter roof?
A more effective construction results with the purlins truly vertical, for three reasons, (1) The purlin is easier built-in or set in hangers at the gable walls. (2) The purlins allow the rafter to be birds mouthed over them, thus avoiding the tendency for the rafter to slide off the roof.
What does the term purlin mean in construction?
Steel construction. In steel construction, the term purlin typically refers to roof framing members that span parallel to the building eave, and support the roof decking or sheeting. The purlins are in turn supported by rafters or walls.
Do you need prefabricated beams for a purlin roof?
On longer spans of purlins it may be necessary to use prefabricated beams, these being dealt with in more detail under the attic roof solution later in this chapter, the beams themselves being illustrated in below picture.
How are the rafters on a roof supported?
One of a series of sloped beams that extend from the ridge or hip to the downslope perimeter or eave, designed to support the roof deck and its associated loads. A longitudinal structural member bridging two or more rafters of a roof. In root construction, a horizontal member supported on the principals and supporting the common rafters.