Purlin Load Capacity Calculator

A purlin is a horizontal structural member commonly used in roofing support systems. They are used to distribute loads from the roof itself to other members of the roof structure such as trusses and beams. Purlins can be made from timber, steel, or other materials. This Z and C Purlin Size Calculator deals with light gauge/cold-formed sections.

Purlins are important members of structural engineering solutions as they are used to deal with loads including gravity loads, wind loads, and snow loads that the roof may be subject to.

While purlins are most commonly found in roof support systems they can also be used for other structural engineering purposes. These purposes can include:

• Z and C Steel Section Purlins can be used on floors as joists or supports to transfer loads from the floor to the underlying load-bearing structural members.
• Purlins can be used in walls, especially cladded walls to ensure loads are distrusted evenly across the wall.
• Purlins can also be used in structures such as sheds, awnings, canopies, barns, and warehouses.

While related purlin span tables and purlin load tables serve separate purposes in the structural design process. Purlin span tables are used to determine the maximum span of purlins based on the structure and design parameters. On the other hand, purlin load tables are used to determine the maximum load a purlin can support. Alternatively the SkyCiv Purlin Spacing Calculator can be used to calculate z and c purlin span.

The distance purlins should be spaced apart depends on a range of factors including design loads, structural factors, material factors, local engineering codes, and the size and shape of the purlins. This purlin span calculator can help engineers determine the correct spacing of cold-formed C and Z purlins.

Steps:

• Step 1: Choose the Purlin Shape of your preference, (C or Z shape). Toggle “Custom Properties” if you have a custom shape.
• Step 2: Enter the Properties of the Purlin Section Refer to the images below for a guide to the geometry of the section.

• Step 3: If you have toggled on “Custom Properties” , enter the section name, area, moments of inertia, and the section modulus.
• Step 4: Enter the roof data. Refer to the roof schematic image below.

• Step 5: Enter the design loads including the dead load (DL), live load (LL), wind load (WL), and snow load (SL). These loads will act as area/pressure loads applied on the roof.
• Step 6: Click “Run”

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SkyCiv offers a wide range of Cloud Structural Analysis and Design Software for engineers. As a constantly evolving tech company, we’re committed to innovating and challenging existing workflows to save engineers time in their work processes and designs.