CLS Timber
(12 Products)CLS timber is kiln-dried, C16-graded softwood for internal studwork and partition framing. Smooth planed faces and eased edges make it straightforward to handle and fit, with 38mm × 63mm and 38mm × 89mm sizes available as individual lengths or packs.
Choose 3x2 CLS for a finished size of 38mm × 63mm, or 4x2 CLS for 38mm × 89mm. Select the length you need, then compare individual lengths and packs. Check the pack quantity and delivery details before ordering.
Understanding CLS Timber
CLS timber takes its name from Canadian Lumber Standard and is recognisable by its smooth planed faces and rounded edges. It provides a regular timber profile for assembling internal stud walls and frames, with flat faces for fixing plasterboard linings.
Kiln drying reduces the timber’s moisture content before use, helping to limit subsequent shrinkage and movement. The C16 strength grade makes it suitable for structural framing where that grade and the chosen dimensions are specified in the design.
Material Range
- 3x2 CLS: C16 studwork timber with finished dimensions of 38mm × 63mm, available in individual lengths and packs for internal framing projects.
- 4x2 CLS: The wider 38mm × 89mm finished profile, also C16 graded and supplied in individual lengths and packs where this size is required.
Choosing Lengths and Packs
Choose lengths to suit your cutting list, allowing for saw cuts and waste. Individual lengths let you order a specific quantity, while packs provide larger quantities of the named size and length.
Check the number of lengths included in each pack, together with the displayed price and delivery details. Pack quantities can differ between products, so use the information shown on the selected item.
Performance Benefits
- Planed finish: Smooth faces provide an even surface for marking out, joining framing members and fixing plasterboard.
- Eased edges: Rounded corners make the timber more comfortable to handle when moving, cutting and positioning lengths.
- Kiln-dried softwood: Drying reduces moisture content before installation and helps limit movement as the timber adjusts to indoor conditions.
- C16 strength grading: A defined strength class for selecting timber to suit the structural design.
Typical Applications
- Internal partitions: Forming timber stud walls during room alterations, refurbishments and internal fit-outs.
- Studwork components: Creating vertical studs, head and sole plates, and noggins within a specified wall layout.
- Structural framing: Internal timber framing where C16 timber of the selected dimensions is required by the design.
Specification & Standards
- BS EN 338: Structural timber strength classes. Defines the strength, stiffness and density properties associated with classifications such as C16.
- BS EN 14081-1: General requirements for strength-graded structural timber, covering grading and marking.
Related Materials and Construction Uses
CLS timber forms the framework behind plasterboard linings, with insulation fitted between the studs where required. Timber fixings connect the frame, while plasterboard screws secure the lining. Door openings, board joints and service routes can be planned into the wall layout before boarding.
Frequently Asked CLS Timber Questions
What Is The Difference Between C16 And C24 CLS Wood?
C16 and C24 are structural timber strength classes, with C24 offering higher strength properties. The appropriate grade depends on the loads and framing design, rather than one grade being the best choice for every job.
Our CLS timber range is C16 graded. For a fuller comparison of the two classes and their uses, read our timber grade guide.
How Does CLS Timber Compare To Other Types Of Timber?
CLS timber has regular finished dimensions, smooth planed faces and eased edges, making it practical for assembling internal studwork. Other timber products offer different dimensions, finishes, treatments and strength grades.
Choose according to the construction requirements. The CLS name alone does not establish a structural span, preservative treatment or suitability for outdoor use.
Can You Use CLS For Stud Wall Applications?
Yes. CLS timber is commonly used for the studs, head and sole plates, and noggins that form internal partition walls. Choose the finished timber dimensions, lengths and strength grade required by the wall design, taking account of the lining and any insulation.
Can CLS Timber Be Used Outside?
CLS describes the timber’s profile and finish, rather than its preservative treatment. Our 4x2 CLS timber is intended for interior applications and is not recommended for outdoor use or direct ground contact.
For outdoor projects, choose timber with treatment suited to the intended exposure. A surface coating alone does not make interior CLS suitable for exterior use.
How Do I Calculate How Much CLS Timber I Need?
Start with a cutting list for the studs, head and sole plates, and noggins in the wall layout. Match those pieces to the available timber lengths, allowing for saw cuts and waste.
For pack orders, check the stated number of lengths supplied and whether you need additional individual lengths to complete the job.
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