A Comprehensive Guide to Types of Purlins and Their Uses

Purlins are horizontal beams that support the roof's rafters, providing structural integrity and distributing the weight evenly. They come in different types, each with its unique characteristics and uses.

Common types of purlins include wood purlins, metal purlins, and composite purlins. Wood purlins are often used in traditional construction due to their natural insulation properties and aesthetic appeal.

Wood purlins can be made from various types of wood, such as spruce, fir, or pine, and are typically spaced 16 to 24 inches apart. Metal purlins, on the other hand, are often used in modern construction due to their durability and resistance to pests and rot.

Metal purlins can be made from steel or aluminum and are commonly used in industrial and commercial buildings. Composite purlins, as the name suggests, are made from a combination of materials, such as wood and metal, and offer a balance of strength and sustainability.

Composite purlins are a popular choice for green buildings due to their reduced environmental impact.

A purlin is a horizontal beam used in building construction to support and stabilize a metal roofing or wall structure. Purlins are typically made of metal, such as steel, aluminum, or hot-dipped galvanized steel.

Metal purlins come in various shapes, including C purlins and Z purlins. They are placed perpendicular to the roof framing members, such as rafters or trusses.

Purlins serve as supporting structures, distributing the load of the roof or wall to the main structural elements. This makes them a crucial component in building construction.

Metal purlins are lightweight yet sturdy, making them cost-effective and easy to handle during installation.

There are two main types of purlins: C purlins and Z purlins. C purlins are shaped like the letter C and are commonly used to support walls and floors, making them ideal for simple span construction.

C purlins are also preferred for cladding due to one side being plain. In contrast, Z purlins are shaped like the letter Z and are often used to support roofs and wall joists.

The shape of Z purlins allows them to save up to 50% on structural sheets compared to hot-rolled angles. They can also be overlapped continuously, making them a better choice for metal buildings with longer spans.

Here's a comparison of C and Z purlins:

In general, both C and Z purlins have their own strengths and weaknesses, and the choice between them depends on the specific needs of the structure.

Wood purlins have traditionally been valued for their natural attributes, providing breathability ideal for certain applications, such as agricultural buildings, where ventilation is key.

Steel purlins offer a strong alternative to wood, addressing many of the shortcomings associated with wood.

Their durability contributes to a longer lifespan of structures, making them a reliable choice.

Steel purlins are also lightweight, facilitating more straightforward installation compared to their wood counterparts.

Wood purlins, on the other hand, require more careful handling due to their heavier nature.

Their lightweight nature makes steel purlins a popular choice for modern construction projects.

In contrast, wood purlins are often preferred for traditional or rustic-style buildings where their natural appearance is a desirable feature.

Steel purlins are a great substitute for conventional wood purlins, offering a range of benefits.

They're lightweight, stable in dimension, and accurate, making them simple to work with. Steel purlins are typically made of cold-formed material, which is thin enough to get through screws.

In extreme temperature changes, steel purlins expand and contract moderately, which is a big plus in harsh weather conditions. Cold-formed steel is rendered in the desired shape by rolling or pressing thin sheets of steel in.

Steel purlins can be made of different metals, including mild steel with normal strength and metals with zinc coating of different GSM. Special coatings can be applied over and above zinc coating for added protection.

C purlins, also known as Cee purlins, are made from galvanized steel and are widely used for reinforcing walls and serving as floor joists. They offer exceptional durability and contribute to the overall stability and longevity of the structures they support.

C purlins can span considerable lengths, making them ideal for various construction builds. They eliminate the need for side drilling or cutting, ensuring a streamlined installation process and assuring straightness throughout.

Z purlins, also known as Zee purlins, are made from galvanized steel and offer overlapping joints, making them exceptionally strong and sturdy. They're a popular choice for large-scale structures due to their ability to provide superior strength and durability.

The unique shape of Z purlins allows for convenient overlapping during installation, enhancing their load-bearing capacity and contributing to more efficient use of materials.

C purlins are shaped like the C alphabet and are primarily used to support walls and floors, making them suitable for simple span construction.

They are also perfect for cladding and can be used in single spans due to their similar extensions on their ends.

C purlins are freestanding and secure, allowing them to be easily managed while being mounted.

Z purlins, on the other hand, are shaped like the Z alphabet and are mostly made using cold-formed or rolled sheets.

They are stronger than C purlins and are often used together at joints and overlaps.

Z purlins can be overlapped continuously, making them a better choice for metal buildings made for longer spans.

In fact, Z purlins can save up to 50% on structural sheets compared to hot-rolled angles.

Z purlins are also more flexible than C purlins due to their angle, which is less than 90 degrees.

This makes them suitable for a variety of purposes, including agricultural and industrial buildings.

Z purlins can support heavy structures and are commonly used in buildings with a bigger roofing or loading capacity.

However, they require more effort and skills to install compared to C purlins.

Shaped Sigma purlins are a type of C-shaped purlin with special ribs that give them good structural properties. They're actually the best of the bunch, outperforming the other two varieties.

These purlins are designed to form the building shell structure's walls and floor joists, making them suitable for supporting the beams needed for flooring. They can also be used in conjunction with C segment purlins for added support.

Sigma purlins are built to last, with their unique design allowing them to withstand various loads and stresses. They're a great option for builders looking for a reliable and durable purlin solution.

In addition to their structural benefits, Sigma purlins can also be customized with features like door mounting, roof clipping, and window trimming. This adds to their versatility and makes them a popular choice among builders.

Galvanized purlins are a popular choice for construction projects that require maximum durability and corrosion resistance. They're ideal for harsh environments like chemical plants or coastal areas where exposure to saltwater would otherwise lead to rusting in unfinished steel.

Galvanized purlins are made by applying a zinc-alloy plating to the metal, creating a protective barrier against corrosion. This makes them outperform non-galvanized alternatives in longevity and resilience.

In fact, galvanized purlins are more corrosive resistant than red oxide purlins, which are more prone to rusting quickly without a finished coat of paint. This is especially important for projects located near the ocean, where galvanized purlins would be a better choice.

Galvanized purlins have some drawbacks, though. They're more difficult to paint when compared to red oxide primer, and they may develop white rust when exposed to moisture. However, they're still a reliable choice for long-lasting support in corrosive environments.

Here's a comparison between red oxide and galvanized purlins:

Wood purlins are a traditional choice for construction projects due to their natural attributes, such as breathability, which is ideal for applications like agricultural buildings.

Steel purlins offer a strong alternative to wood, addressing many of its shortcomings, including a longer lifespan and easier installation.

Wood purlins are a good option for projects where ventilation is key, like agricultural buildings.

Steel purlins are more durable than wood purlins, contributing to a longer lifespan of structures.

Purlin sizes can vary from 4” to 12” with a flange width of 1-½” to 4”. They're available in custom sizes and lengths depending on the project's requirements.

The most common metal purlin sizes are 12g (up to 21 inches), 14g (up to 24 inches), and 16g (up to 16 inches). This diversity in sizes allows for flexibility in accommodating different structural requirements.

Metal purlin spacing is crucial for ensuring structural integrity and stability. The spacing between purlins is determined based on the anticipated weight the structure will carry and the load capacity of the metal panels.

Purlins are available in a wide range of sizes, from 4” up to 12” with a flange width of 1-½” up to 4”. They can be customized to fit specific project requirements.

Bansal C section purlins are available with a web height up to 300 mm and thickness up to 3.2 mm. This allows for flexibility in accommodating different structural requirements.

Metal purlin sizes are diverse and versatile, catering to a range of construction needs. They are offered in various dimensions, including 12g (up to 21 inches), 14g (up to 24 inches), and 16g (up to 16 inches).

Purlins can be manufactured to the exact specifications of the customer, making them easily modified for use in buildings of various sizes.

Spacing is a critical factor in determining the structural integrity and stability of a construction project. Metal purlin spacing plays a crucial role in ensuring the structural integrity and stability of a construction project.

For heavier loads, shorter distances between purlins are required to provide sufficient support. Finding the right balance in purlin spacing is essential.

Metal panel and purlin load charts aid in determining the optimal spacing for each job. By finding the optimal purlin spacing, we can help clients achieve cost-efficiency without compromising the structural integrity of their project.

The correct purlin spacing is determined based on the anticipated weight the structure will carry and the load capacity of the metal panels.