Peripheral Purlin Bridge Details in 2d AutoCAD, dwg file.

This Architectural Drawing is AutoCAD 2d drawing of Peripheral Purlin Bridge Details in 2d AutoCAD, dwg file. Purlins are installed horizontally under metal roofs. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. Purlins are 2 by 4 feet and are installed much like metal roofing.