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CLS Timber & Scant

CLS timber, short for Canadian Lumber Standard timber, is a popular choice in construction. It’s mainly used for interior jobs like non-load-bearing walls and framing.

So, what is CLS timber? It’s timber sourced from sustainable forests in Canada and Europe, and it’s graded to ensure strength, consistency, and durability.

Common CLS timber sizes include:

  • 2x4 inches (47x100mm)

  • 3x2 inches (47x75mm)

  • 4x2 inches (47x50mm)

The 4x2 size is especially popular for building frames in timber structures.

Understanding the meaning of CLS timber highlights its value in delivering precise, high-quality construction.

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  • CLS Timber PEFC 50 x 75 x 2400mm CLS Timber PEFC 50 x 75 x 2400mm

    CLS Timber PEFC 50 x 75 x 2400mm

    Canadian Lumber Standard (CLS) is a structural timber available in a variety of sections and lengths most used in construction. CLS has PAR rounded four corners for ease of handling. It has been kiln dried enabling protection against decay and making the...
  • CLS Timber PEFC 50 x 75 x 3000mm CLS Timber PEFC 50 x 75 x 3000mm

    CLS Timber PEFC 50 x 75 x 3000mm

    Canadian Lumber Standard (CLS) is a structural timber available in a variety of sections and lengths most used in construction. CLS has PAR rounded four corners for ease of handling. It has been kiln dried enabling protection against decay and making the...
  • CLS Timber PEFC 38 x 89 x 2400mm CLS Timber PEFC 38 x 89 x 2400mm

    CLS Timber PEFC 38 x 89 x 2400mm

    Canadian Lumber Standard (CLS) timber is a high-quality structural wood commonly used in construction projects. Available in a range of CLS timber sizes, including 3x2 CLS timber and 4x2 CLS timber, it is strength-graded to C16, ensuring durability and...
  • CLS Timber PEFC 38 x 89 x 3000mm CLS Timber PEFC 38 x 89 x 3000mm

    CLS Timber PEFC 38 x 89 x 3000mm

    Canadian Lumber Standard (CLS) is a structural timber available in a variety of sections and lengths most used in construction. CLS has PAR rounded four corners for ease of handling. It has been kiln dried enabling protection against decay and making the...
  • Scant Timber S4S PEFC 42 x 69 x 2400mm Scant Timber S4S PEFC 42 x 69 x 2400mm

    Scant Timber S4S PEFC 42 x 69 x 2400mm

    Scant is a structural timber available in a variety of sections and lengths most used in construction, mainly used for internal construction timbers within the building envelope, tiling batten, framing and roof timbers, internal joists, sole pates.
  • CLS Timber PEFC 50 x 75 x 4800mm CLS Timber PEFC 50 x 75 x 4800mm

    CLS Timber PEFC 50 x 75 x 4800mm

    Canadian Lumber Standard (CLS) is a structural timber available in a variety of sections and lengths most used in construction. CLS has PAR rounded four corners for ease of handling. It has been kiln dried enabling protection against decay and making the...
  • CLS Timber UC2 Treated PEFC 38 x 89mm CLS Timber UC2 Treated PEFC 38 x 89mm

    CLS Timber UC2 Treated PEFC 38 x 89mm

    CLS stands for "Canadian Lumber Size". It is for internaluse,mainly for timber frames and partitian walls.Itis finished on all sidesgiving ita smaller cross-section than traditional sawn timber. With a long and proud tradition of supplying quality...
  • Scant Timber S4S PEFC 42 x 69 x 3600mm Scant Timber S4S PEFC 42 x 69 x 3600mm

    Scant Timber S4S PEFC 42 x 69 x 3600mm

    Scant is a structural timber available in a variety of sections and lengths most used in construction, mainly used for internal construction timbers within the building envelope, tiling batten, framing and roof timbers, internal joists, sole pates.
  • CLS Timber FSC 50 x 100 x 2400mm CLS Timber FSC 50 x 100 x 2400mm

    CLS Timber FSC 50 x 100 x 2400mm

    Canadian Lumber Standard (CLS) is a structural timber available in a variety of sections and lengths most used in construction. CLS has PAR rounded four corners for ease of handling. It has been kiln dried enabling protection against decay and making the...
  • CLS Timber PEFC 38 x 140 x 4800mm CLS Timber PEFC 38 x 140 x 4800mm

    CLS Timber PEFC 38 x 140 x 4800mm

    Canadian Lumber Standard (CLS) is a structural timber available in a variety of sections and lengths most commonly used in construction. CLS has PAR rounded four corners for ease of handling. It has been kiln dried enabling protection against decay and...
  • Scant Timber S4S PEFC 42 x 69 x 3000mm Scant Timber S4S PEFC 42 x 69 x 3000mm

    Scant Timber S4S PEFC 42 x 69 x 3000mm

    Scant is a structural timber available in a variety of sections and lengths most used in construction, mainly used for internal construction timbers within the building envelope, tiling batten, framing and roof timbers, internal joists, sole pates.
  • CLS Timber PEFC 38 x 89 x 4800mm CLS Timber PEFC 38 x 89 x 4800mm

    CLS Timber PEFC 38 x 89 x 4800mm

    Canadian Lumber Standard (CLS) is a structural timber available in a variety of sections and lengths most commonly used in construction. It has been strength graded to C16 providing the highest structural performance for high quality products. CLS has...
  • CLS Timber FSC 50 x 100 x 3000mm CLS Timber FSC 50 x 100 x 3000mm

    CLS Timber FSC 50 x 100 x 3000mm

    Canadian Lumber Standard (CLS) is a structural timber available in a variety of sections and lengths most commonly used in construction. CLS has PAR rounded four corners for ease of handling. It has been kiln dried enabling protection against decay and...
  • CLS Timber 38 x 140 x 2400mm CLS Timber 38 x 140 x 2400mm

    CLS Timber 38 x 140 x 2400mm

    Canadian Lumber Standard (CLS) is a structural timber available in a variety of sections and lengths most commonly used in construction. CLS has PAR rounded four corners for ease of handling. It has been kiln dried enabling protection against decay and...
  • CLS Timber FSC 38 x 63 x 2400mm CLS Timber FSC 38 x 63 x 2400mm

    CLS Timber FSC 38 x 63 x 2400mm

    Canadian Lumber Standard (CLS) is a structural timber available in a variety of sections and lengths most used in construction. CLS has PAR rounded four corners for ease of handling. It has been kiln dried enabling protection against decay and making the...
  • CLS Timber FSC 38 x 63 x 3000mm CLS Timber FSC 38 x 63 x 3000mm

    CLS Timber FSC 38 x 63 x 3000mm

    Canadian Lumber Standard (CLS) is a structural timber available in a variety of sections and lengths most used in construction. CLS has PAR rounded four corners for ease of handling. It has been kiln dried enabling protection against decay and making the...
  • CLS Timber FSC 38 x 63 x 4800mm CLS Timber FSC 38 x 63 x 4800mm

    CLS Timber FSC 38 x 63 x 4800mm

    Canadian Lumber Standard (CLS) is a structural timber available in a variety of sections and lengths most used in construction. CLS has PAR rounded four corners for ease of handling. It has been kiln dried enabling protection against decay and making the...
  • CLS Timber FSC 50 x 100 x 4800mm CLS Timber FSC 50 x 100 x 4800mm

    CLS Timber FSC 50 x 100 x 4800mm

    Canadian Lumber Standard (CLS) is a structural timber available in a variety of sections and lengths most commonly used in construction. CLS has PAR rounded four corners for ease of handling. It has been kiln dried enabling protection against decay and...
  • Scant Timber S4S PEFC 42 x 69 x 4800mm Scant Timber S4S PEFC 42 x 69 x 4800mm

    Scant Timber S4S PEFC 42 x 69 x 4800mm

    Scant is a structural timber available in a variety of sections and lengths most used in construction, mainly used for internal construction timbers within the building envelope, tiling batten, framing and roof timbers, internal joists, sole pates.

What is CLS Timber?

CLS timber stands for Canadian Lumber Standard timber. It's most commonly used in timber frame construction and for internal or partition walls.

Unlike rough-sawn timber, CLS timber is smooth and planed on all sides, giving it a smaller cross-section and a more finished appearance.

What is CLS Timber Used For?

CLS timber (short for Canadian Lumber Size) is ideal for building non load-bearing walls such as stud partitions. It’s often used in place of Scant timber, but with a few differences.

  • It has rounded corners, making it thinner and narrower than Scant.
  • A standard piece of CLS timber sized at 50 x 75mm finishes at 38 x 63mm after planing.
  • Common lengths include 2.4m and 4.2m, with some branches also stocking 3.0m pieces.

High-quality CLS timber is usually imported from Sweden, Denmark, Germany, the Baltic regions, and Canada.

What is Scant Timber?

Scant timber is another type of planed timber used for internal framing, especially for stud walls and occasionally for rafters (known as framing).

Like CLS, it’s surfaced on all four sides, but with some key differences:

  • The corners are squared, not rounded
  • The finished size is typically 42 x 69mm
  • Available in lengths of 2.4m, 3.0m, 3.6m, and 4.8m

Scant is more commonly used in areas like Manchester and Lancashire.

Timber Quality and Grading

At Howarth Timber & Building Supplies, we only stock kiln-dried CLS and Scant timber to help prevent warping and keep the timber straight.

Most of our timber is Whitewood (Picea Abies) and is imported from trusted sources. The majority is graded to C16, offering reliable quality for non load-bearing applications. However, we also stock ungraded timber, which is still suitable for partition walls.

Frequently Asked Questions

Can I use CLS timber outside?
CLS timber should only be used outside if it has been treated, to ensure it is suitably resistant to external climate conditions that can cause issues such as rot and decay.

How to guides

A Guide to CLS timber

An article featuring everything you need to know about CLS timber in one place, from its benefits to the projects it can be used for! 

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