Purlins are horizontal beams or rods used for structural support in a structure, usually under a roof. Purlins are supported by the rafters or walls of a building. These are most commonly used in metal construction, but in wood-frame construction they also replace closely spaced rafters. The purlins of the roof support the weight of the roof deck. Roof decks are wood, plywood, or metal sheets that form the surface of the roof. This is usually filled with some sort of weatherproof material, constructed of concrete, and usually insulating.

There are many types of purlins, which are divided into several groups according to the different materials and shapes. Different purlins are used for a variety of purposes, including structural wall or floor support. Purlins are necessary because the sheets on the roof have no frame to support, so purlins are important to the roof structure.

Purlins carry roof deck or sheathing loads and are supported by large rafters and/or building walls, steel beams, etc. In contrast to closely spaced rafters, the use of purlins is common in both prefabricated metal building systems and ancient columns, beams and new rod construction methods for frame construction.

Purlins transmit roof loads to the primary structural elements that support the roof; the form and arrangement of purlins is a design factor that depends on roof load conditions and the length of the limiting slab used. Ultimately, local building codes should always be understood and implemented in the design of concrete roof structures.

Steel purlins are an alternative to traditional wooden purlins. They are lightweight, dimensionally stable, accurate and simple. They expand and contract moderately during extreme temperature changes. Steel purlins are usually made of cold-formed material that is thin enough to pass through the screws. Cold-formed steel is made into the desired shape by rolling or pressing a thin sheet of steel. For producers, it costs less than hot rolled steel and is therefore easier to handle. While cold-formed steel is stronger under strain than hot-formed steel, it is more prone to cracking than bending.

Purlins are made of different metals. Some are simple mild steel with normal strength, some have zinc coating with different GSM. In inclement weather, special coatings can be applied on and over the zinc coating.

C-shaped purlins:

As the name suggests, C-channel steel for sale are formed according to the letter C and are mainly used to support walls and floors. C-section purlins or CEE-section purlins are used to shape the wall and floor joists of the building shell structure, making it also suitable for beams needed to support floors. These can also be used with our C-segment purlins with door mounts, roof clips, window trim, railings and side rails.

We have similar extensions at the ends of both purlins in section C, which means they can be used in a single span. These are self-contained and secure, allowing them to be easily managed at install time, while also providing stable support in the system.

Available sizes for Steel C purlins:

Bansal C-channel steel are available in a variety of thicknesses and can be manufactured to customers' exact specifications in unlimited lengths, allowing them to be easily modified for use in buildings of all sizes. Bansal also produces undrilled or pre-drilled holes with different diameters (oval and round holes of any size are available on request). Available in roll heights up to 300mm and thicknesses up to 3.2mm.

Z-shaped purlins:

Another form of Z-purlin is stronger than C-purlin, and is mostly used in seams and overlaps. Z purlins or zed purlins are horizontal beams that are used to shape the roof and wall joists of the building shell structure. They sit between the roof slab and the building and act as slab supports to ensure it is securely attached and held in place. Z purlins are most commonly used in agricultural and industrial construction due to their relatively high flexibility and lightweight properties, which make them easily adaptable to use in a variety of different sizes.

Available sizes for Z purlins:

At Bansal Roofing Products Ltd, we manufacture Z purlins in a wide range of thicknesses to any length to suit your exact requirements. We can also manufacture undrilled or pre-drilled holes of any diameter according to your requirements. (Oval and circular holes of any size are available upon request). Available in roll heights up to 300mm and thicknesses up to 3.2mm.

C-shaped SIGMA purlins:

C-shapes with special ribs (web bending) are called "SIGMA" purlins.

These types of purlins have good structural properties and replace the two types of purlins described above.

Sigma section purlins are used to shape the wall and floor joists of the building shell structure, making it also suitable for beams needed to support floors. These can also be used with our C-segment purlins with door mounts, roof clips, window trim, railings and side rails.

Dimensions suitable for SIGMA purlins:

Bansal SIGMA profile purlins are available in a variety of thicknesses and manufactured to the exact specifications of the customer in unlimited lengths, making them easy to modify for use in buildings of all sizes. Bansal also produces undrilled or pre-drilled holes with different diameters (oval and round holes of any size are available on request). Available in roll heights up to 300mm and thicknesses up to 3.2mm.

What is the use of purlins in steel structure buildings?

To understand this, we really need to dive into the basics of roof purlins in metal construction. Purlins are an integral part of prefabricated structural ladle. This structural support extends vertically across the rafter beams. Purlins are often referred to as "sheets" and provide the roof portion of the secondary frame of a steel building. Metal roof purlins serve three structural functions.

First, the roof is protected by purlins. Second, the purlins connect the rafters together, stabilizing and reinforcing the rigid frame of the frame. Third, purlins provide additional support between the spans of the individual frame compartments. As an added benefit, the purlins increase the system's resistance to excessive rainfall.