CLS Wood - CLS Framing & Studwork | DIY Building Supplies

Frequently Asked Questions

What is CLS Timber Used For?

Ever wondered, what is CLS Timber and what do I use it for? C16 Timber is a versatile, structural timber commonly employed in constructing timber-framed homes, typically in stud walling, carcassing, interior framing, and partitioning. Its C16 grade ensures exceptional strength, making it well-suited for various interior construction uses. You will often see it used in creating partitions in new builds or conversions.

What Does CLS Stand For?

CLS stands for “Canadian Lumber Standard” as it was originally sourced in Canada. Nowadays it is grown and sourced from various countries including grown here in the UK, but CLS is still used as a common name to identify the product. CLS is typically used for structural projects such as stud walls and partitioning, and is regularised on all sides, giving it a smaller profile than standard 3x2 timber by a few millimetres.

Kiln Dried Timber

Kiln-dried timber is wood that has been carefully dried in a controlled environment, typically a large oven or kiln. This process removes excess moisture from the wood, reducing its moisture content to a specific level suitable for various applications. Kiln drying helps to minimize the wood's susceptibility to warping, shrinking, and cracking, while also improving its strength and stability. The controlled drying process ensures that the wood reaches a uniform moisture content throughout, making it more predictable and consistent in its performance. Kiln-dried timber is often preferred for construction, furniture making, and woodworking projects where stability, strength, and dimensional accuracy are important factors.

What is Regularised Timber?

Regularised timber refers to timber that has been processed to achieve consistent dimensions and smooth surfaces. This processing typically involves trimming and planing the wood to standardized sizes and shapes, ensuring uniformity in thickness, width, and length. This often results in the timber being a few mm smaller in width and thickness than their "official" size, but is so minimal that it is likely to have no impact on the large majority of projects.

What Does C16 Stand For?

In the UK, timber is often graded based on it’s type of timber and it’s bend strength - The "C" represents the type of wood, which in this case is coniferous, and the "16" denotes its bend strength grading - assessed by the presence (or lack of) knots, imperfections and more. We also use C24 timber, which has a higher bend strength for even greater load-bearing projects.

C16 timber is commonly used in construction for framing and partitioning. It's characterised by its strength and suitability for moderate load-bearing applications. Builders and contractors often utilise C16 timber in projects where a robust yet reasonably priced timber option is required, such as in domestic construction for wall framing, roofing, and general structural support.

Why Choose Our CLS Timber Collection?

Our carefully selected CLS (Canadian Lumber Standard) timber delivers the consistent quality and dimensional accuracy that both trade professionals and discerning DIY enthusiasts demand. Sourced from leading UK suppliers including James Jones & Sons and Norbord, every piece meets rigorous C24 grading standards, ensuring you receive timber that's been precision-machined to exact specifications.

What sets our CLS timber apart:

Kiln-dried to 18% moisture content – preventing warping, shrinkage, and structural movement
Eased edges and rounded corners – reducing splinters whilst maintaining structural integrity
Consistent dimensions – eliminating the variations found in traditional sawn timber
Pressure-treated options available – providing enhanced durability for external applications

Complete Range for Every Application

Whether you're constructing internal stud walls, floor joists, or roof trusses, our comprehensive CLS timber range covers all standard construction requirements. From 38mm x 63mm studwork through to substantial 63mm x 225mm structural members, we stock the dimensions you need for professional results.

Our most popular sizes include:

38mm x 89mm – ideal for internal partition walls and light structural work
38mm x 140mm – perfect for standard floor joists and roof rafters
47mm x 200mm – excellent for heavy-duty structural applications

Each dimension is available in multiple lengths from 2.4m up to 4.8m, ensuring you can minimise waste whilst achieving the spans your project requires.

Expert Guidance When You Need It Most

Selecting the correct timber specification can be complex, particularly when building regulations and structural requirements come into play. That's where our expertise makes the difference. Our experienced team understands the nuances of C24 grading, span tables, and load-bearing requirements – knowledge we're always happy to share.

We regularly assist customers in determining appropriate joist spacing for floor applications, calculating beam sizes for load-bearing walls, and specifying treatment levels for various exposure conditions. This technical support ensures your project not only meets current building standards but delivers the long-term performance you expect.

Quality You Can Build Upon

Every piece of CLS timber in our collection undergoes rigorous quality checks before leaving our Nottingham warehouse. This attention to detail reflects our commitment to providing materials that trade professionals trust and recommend. When you choose DIY Building Supplies, you're not just purchasing timber – you're investing in the reliability and expertise that comes from years of supporting successful projects across the UK.

From our warehouse in Stapleford to building sites nationwide, we ensure your CLS timber arrives in perfect condition, ready for immediate use. Our robust packaging and careful handling procedures protect your investment from despatch through to delivery.

Ready to start your project? Our CLS timber collection combines the precision of modern manufacturing with the natural strength that has made timber Britain's preferred structural material. Whether you're a seasoned tradesperson or tackling your first major DIY project, we're here to ensure you have exactly what you need for professional results.