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What Are Roof Purlins?

What Ate Roof Purlins
If you’re in the business of building houses, you’ll know how fundamental structural support is, especially when it comes to roofs. Purlins, beams, struts, and rafters all work together to form the roof of a building. But just how do these components work? And, more importantly, what are they?

The term ‘purlin’ is used to describe the horizontal beams used for structural support in buildings. Most commonly, purlins play a crucial role in the roof structure of buildings. Typically, purlins are supported by both rafters or building walls when laid horizontally. With this support, the roof deck can be laid comfortably and safely over the purlins. By ‘roof deck’, we mean any metal sheeting, plyboard, or wooden panels used to create the surface of the roof.

In essence, then, purlins simply create a horizontal frame that is aimed at supporting the entire weight of the roof deck, no matter which materials are used. What’s more, purlins also improve the rigidity and breadth of buildings by acting as a mid-span support, while also providing a nailing surface for any end panels and drip edges.

What Are C Purlins?

‘C purlins’ for example are used over walls, floor joists, rafters, and as studs for walls, and get their name from their square ‘C’ shape.

What Are Z Purlins?

This type of purlin is used when joints need to overlap. It is generally stronger and more reliable than its cousin the ‘C’ purlin, hence its use in much larger-scale structures such as commercial and industrial buildings. This type also gets its name from, you’ve guessed it, its resemblance to a ‘Z’.

RHS purlins

This unique type of purlin is used in roofs where the support structure is visible after the project is completed. They usually take the form of a hollow, rectangular tube (instead of steel bars).

What Are The Different Types Of Purlins?

Aside from ‘C’, ‘Z’, and RHS purlins, these structural support tools can also be categorised by the material they are made from. While wood roof purlins are by far the most traditional and long-standing purlin type, there are also steel purlin types too. Many people nowadays opt for galvanised steel roof purlins due to their durability, flexibility in shape, cost, and all-round structural strength.

Wood Purlins

If the task at hand requires the use of fibre cement sheeting, wooden purlins are your best bet as these two materials combine well together.

Wood purlins, when combined with other roofing materials, have breathability as a core benefit. However, due to their wooden properties, they can rot if not well-maintained and inspected over long periods of time. It is important that wood purlins are dried before their installation to avoid dampness and sagging.

What Are Galvanised Steel Purlins?

Nowadays, these purlins are replacements for wood purlins. Not only are they accurate, stable, and lightweight, but they also can contract and expanding suitably in extreme temperature fluctuations — making them a better option for all climates.

Usually, steel purlins are formed out of cold-formed steel. This steel type is thin enough to drill screws through and is made by rolling multiple steel sheets together into the desired shape. A benefit of this type of material is its cost; it is far less than hot-rolled steel.

How Are Purlins Made?

When it comes to steel purlins, there is a long and complex manufacturing process for these pieces of structural equipment. Steel roof purlins are made from hot-dipped steel that has been galvanised and coated (like all other steel products in the construction industry). The reason for this coating is to protect the steel from corrosion in internal and external environments. After the purlin is made, another layer of paint is applied to avoid zinc-related corrosion.

How To Buy Roof Purlins?

If you’re looking to buy purlins — either in bulk or by the unit — you’ve come to the right place. Wecare experts in all thing’s roofs and stock a comprehensive range of purlins as well as other essential roofing materials and accessories.

Browse our full range of purlins here or, if you have any questions, get in touch with our experts today by emailing us at info@colourcladprofiles.com or calling us on 01278 557002. Get In Touch
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