A horizontal bar used for structural support is known as a purlin. Purlins are mostly used below the roof and are supported by the building’s walls or rafters. We can also say that purlins reinforce the rigid framing by bringing the rafters together. Steel purlins are frequently used in metal buildings, but sometimes they are used to replace closely spaced rafters in wood-frame structures.

Nowadays, purlin manufacturers commonly produce two types of purlins- Z and C purlins.

C purlins are shaped like the C alphabet and are primarily used to support walls and floors. As one side of this purlin is plain, it is preferred for cladding. These purlins are also perfect for simple span construction. C purlins are built to shape a building’s shell structure walls and floor joists.C purlin has an angle of 90 degrees and can be used for a variety of purposes.It cannot Overlap Continuously and therefore used for supporting the beams required for flooring.It have relatively less strength and are easy to install.

Z Purlins are similar to that of the Z alphabet. They are mostly made using cold-formed or rolled sheets. As compared to hot-rolled angles, Z purlins are known to save up to 50% on structural sheets. Z purlins are built to shape a building’s shell structure’s roof and wall joists.It has an angle that is less than 90 degrees and is more flexible. It can be overlapped continuously in metal buildings made for longer spans .The modulus of the flexural section of Z purlin is slightly larger and symmetrically increase vertically. Hence, Z purlins are better suited for roofs with large slopes.It usually sit between roofing sheets to provide support.These are extremely strong and can support heavy structures although, Therefore, in buildings with a bigger roofing or loading capacity, Z purlins would be a better choice. They are commonly used in agricultural and industrial buildings.These are required more effort and skills to Install.