Subpurlin

Definition

A subpurlin is a small roof framing member that spans between joists and purlins.

Purpose

The purpose of a subpurlin is to provide additional support for the roof structure, distributing loads between joists and purlins to ensure stability and strength.

Examples of Use

• In large commercial roofs, subpurlins help distribute the weight of the roofing material evenly.
• Industrial buildings use subpurlins to enhance the structural integrity of wide-span roofs.
• Agricultural structures, like barns, employ subpurlins to support roofing materials and withstand heavy snow loads.

Related Terms

• Purlin: A horizontal beam along the length of a roof, resting on the main rafters and supporting the roof deck.
• Joist: A horizontal structural member used to support floors or roofs.
• Rafter: A sloping beam that supports the roof deck and transmits loads to the walls.

Notes

Subpurlins are essential in large roof structures where additional support is needed to prevent sagging and ensure long-term durability.