Roof Purlin Cleats – Purpose And Different Types

What are Roof Purlin Cleats?

Roof purlin cleats are used to support the roofs of residential or industrial structures. It is a long-lasting, quick, easily installable adaptable link. These are pre-drilled to fit standard purlin holes and are available in bolt-on or weld-on forms. If you want roof purlin cleats, you must use the product code that corresponds to the cleats you want as per CAD drawings related to your project. If only one side needs to be bolted, you will only need one cleat. For some projects, it is better to weld the cleats on the roof truss instead of bolting them.

Roof Purlin Cleats
Fig 1: Roof Purlin Cleats
Source: Raj Roofing Co.

By default, all cleats on roof truss are made of steel that hasn’t been painted. If needed, the finish can be powder coated or galvanized. Hot-rolled angle pieces are commonly used to make roof purlin cleats, which can be single or double. Many practical advantages can be found in using single cleats, including the fact that they require just half of the material and are reasonably straightforward to install and handy when erecting beams close together when space is at a premium. The longest standard cleat is around 450mm long. If cleats are needed that are longer than this, they must be made by the fabricator.

Purpose of Roof Purlin Cleats

Some of the purposes of Roof Purlin Cleats are:

  • Its main function is to prevent the purlins from tilting.
  • For roof slopes over 30°, stiffened purlin cleats are used.
  • Moreover, stiffened cleats are used on tiles roof construction.
  • It is especially good for applications that need to be hidden.
  • For the four bolt connection to the section, M12 Grade 8.8 bolts are used, and for the bolt-on cleats, two M16 Grade 8.8 bolts hold the baseplate to the steel structure.
  • There is an extra 18mm hole for attaching a safety harness connection.

Types of Roof Purlin Cleats

Some of the types of roof purlin cleats are:

  • Double Bolt On Cleats: The double bolt-on cleat can be put in the middle of a rafter or to the left or right of the center for extensions. It is great for adding on to existing buildings because it doesn’t require welding at a high level. If you want to use it as an offset cleat, you need a wood support plate. For a wood connection, you need a 14mm hole, and for a steel connection, you need an 18mm hole. It gets rid of welding.
Bolt-on Cleat
Fig 2: Bolt-on Cleat
Source: Rhino Steel Cladding
  • Welded Cleats: Welded cleats can be added for connecting roof timbers to steel rafters. They can be built in any shape or design you can imagine. They need to be welded to the mainframe before installing the structure.
Weld-on Cleats
Fig 3: Weld-on Cleats
Source: Builder Bill


The roof purlin cleat is perfect for joining or connecting Cee or Zed sections. Most of the time, they connect wall girts to columns, roof battens or roof purlins to rafters, and other similar things.

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