close up of glulam beam

Timber is a construction material commonly used in load-bearing situations. When used for this purpose, the timber is typically graded to strength classes C16, C24 and TR26 here in the UK. TR26 timber is commonly used in the production of roof trusses and flanges of open web joists. This is due to numerous characteristics including strength and weight. 

How is Timber Graded?

To grade timber, it is sorted into groups where the timber types have the same appearance or structural properties in common. It’s important to know the terms used in the grading process and the implied properties and characteristics of each grade. 

Sorting based on appearance is carried out differently to the sorting based on structural properties. The two types are treated separately during the grading process due to cases where timber has both characteristics. 

In the process, timber undergoes the following grading tests:

  • Appearance grading
  • Structural grading
  • Visual stress grading
  • Machine stress grading
  • Machine proof grading
  • In-grade testing
  • Stress grades
  • Quality control

Why is Timber Graded?

The timber grading process is carried out to ensure that it’s fit for purpose. For example, timber may need to be tested to ensure structural safety and economic use of the material. This will also allow poorer pieces of timber to be rejected to improve and guarantee the properties of what is passed. 

When timber is graded by machine, it has to pass certain tests, the main one being a test of the deflection of the piece of material under applied pressure. If the material passes this test, it is given a grade stamp which helps manufacturers to identify the grade. A similar stamp is given when the visual grading takes place. This helps the user or inspector work out the quality of the timber. 

The Characteristics of TR26 Timber

TR26 timber is classified as a sustainable source of timber in accordance with the BS EN 14081. It is kiln-dried and planed all round. The timber is lighter in weight but this does not compromise the strength capabilities that it has. It is designed to improve dimensional stability, all whilst being regularised to a consistent finish. 

What Does Pasquill Use TR26 Graded Timber for?

Here at Pasquill, we use TR26 timber for all our roof truss products as we believe that it’s the strongest and most structurally reliable material we can offer. All our components are manufactured using high-quality PEFC™ TR26 grade timber joined together with MiTek steel connection plates. 

Environmental Impact

We make sure that our timber is environmentally friendly and follows the PEFC and FSC certification schemes which provide evidence of this. We also have a low carbon footprint as our timber requires less energy to produce than other types of construction material. One of the great things about timber is its potential for re-use and recycling at the end of its life. We produce all our trusses off-site which removes the unwanted waste usually caused by on-site manufacturing. 

Want to find out more about our TR26 timber products? Get in touch with your local Pasquil design centre.

Latest Blog Posts