Common Timber Grades Explained

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As you will be able to see from our excellent selection of timber and sheet materials here at Travis Perkins, we have products in stock to suit a wide variety of construction projects and repair jobs that you may be working on.

Before you make any purchase though, it is important that you know about the different grades of timber that are available. This is because the quality and suitability of the material will change from one grade to the next.

Why timber grading is important

When timber is graded, the boards are assessed on their strength, quality, appearance and suitability for certain applications.

Picking the correct grade of timber for your project will therefore mean you have materials which suit the structural integrity, durability and design needed for a job to be a success. Safety standards will also be met when you use graded timber for its intended purpose.

To put this into context, you likely wouldn’t use the same type of timber material for a load-bearing structure as you would when creating a decorative piece of furniture.

The different types of timber grading processes

The actual process of inspecting timber boards to assign them to a grade is set out into these three categories:

1. Defect grading – Where elements which could compromise the performance of timber is identified, including cracks, or loose knots.
 

2. Machine grading – Where the structural property of the timber is assessed, to determine aspects such as the material’s load-bearing capacity.
 

3. Visual grading – Where timber is assessed for its structural features and appearance, with aspects like natural imperfections, knot sizes and grain patterns all considered.

Common timber grades and what they mean

When you shop for timber for your next construction project, take note of the following grades listed against the material:

Fifth-Grade Timber

An affordable type of timber, this graded material has a durable and versatile design along with minimal defects.

Often used for non-structural construction work and landscaping projects, you can expect to find fifth-grade (5ths) timber forming the build of items like garden sheds, outdoor furniture and general joinery and trim work.

Strength Class Graded Timber

Strength class graded timber is assigned a code based on its load-bearing capabilities.

With the C in the code meaning ‘conifer’ due to most structural timber sold in the UK being derived from softwoods, each number will then refer to a specific strength class:

• C16 timber has a medium to higher strength and quality, making it suitable for work where durability and strength are both needed. Stud walls, joists and roofing battens can all be constructed using this grade of material.
   

• C24 timber is often more expensive than C16 timber, but delivers with enhanced stiffness, durability and strength. The material suits being used for heavy-duty applications, such as the load-bearing feature of a balcony.

You can find much more information about strength class graded timber within this in-depth guide.

Unsorted Grade Timber

The highest grade of timber available, unsorted grade timber catches the eye for its clean finish which features very little defects or knots.

Because of its appealing design, this material is frequently sought out by joiners who want to create aesthetically pleasing window frames, doors and furniture. 
 

Now that you know about the grades of timber and what each one means, make sure you also fully understand the correct timber size you need for your next construction job by reading another of our helpful guides.

Ready to plan out your project? We are your local timber specialist and can provide you with a dedicated timber service so that your individual requirements are met time and time again.