Our CLS studwork timber is C16-graded, kiln-dried softwood with a planed finish and eased edges, available in 3x2 (38x63mm) and 4x2 (38x89mm) — also written 2x3 and 2x4, and known nominally as 75 x 50mm and 100 x 50mm stud timber — in lengths from 2.4m to 4.8m. Manufactured to Canadian Lumber Standard (CLS) specifications for consistent sizing and stability, it is ideal for internal stud walls, partitions and roof framing, with a 3-5 working day lead time to mainland UK.
What is CLS Timber?
CLS timber stands for Canadian Lumber Standard — kiln-dried softwood that is planed all round with eased (rounded) edges for a smooth, consistent finish. It is the UK's standard timber for internal stud walls, partitions and framing, because its precise, uniform sizing makes for fast, accurate building. Our CLS studwork timber is C16 structural grade in the two most-used sizes, 3x2 and 4x2. The name simply refers to the sizing standard — CLS is planed and dried for clean internal work, which is what sets it apart from rough-sawn timber.
CLS Timber Sizes
| Size | Nominal (metric) | Actual (planed) | Lengths Available |
| 3x2 (2x3) | 75 x 50mm | 38 x 63mm | 2.4m, 3m, 4.8m |
| 4x2 (2x4) | 100 x 50mm | 38 x 89mm | 2.4m, 3m, 4.8m |
You'll also see 3x2 CLS listed as 75 x 50mm and 4x2 CLS as 100 x 50mm stud timber — these nominal sizes refer to the same planed 38 x 63mm and 38 x 89mm sections. CLS timber is sized to Canadian Lumber Standard, so the actual planed dimensions are slightly smaller than the nominal imperial size. The rounded corners and planed faces are standard CLS features.
Technical Specification
| Grade | C16 structural |
| Sizes | 3x2 / 2x3 (75 x 50mm nominal, 38 x 63mm planed) and 4x2 / 2x4 (100 x 50mm nominal, 38 x 89mm planed) |
| Lengths | 2.4m, 3m, 4.8m |
| Finish | Planed all round, eased (rounded) edges |
| Drying | Kiln-dried for stability |
| Standard | Canadian Lumber Standard (CLS) |
| Material | Softwood |
| Lead time | 3-5 working days (mainland UK) |
Common Uses
CLS studwork timber is widely used for internal stud wall framing, partition walls and door linings, roof trusses and loft framing, boxing in pipework, lightweight furniture framing and, when treated, sheltered structures such as sheds and fencing rails. Its consistent sizing and planed finish make it the standard choice for fast, accurate stud work.
C16 Grade and Kiln Drying
The C16 structural grade provides reliable strength for stud walls and light framing, while kiln drying reduces moisture content to help prevent warping or shrinking after installation. The planed surfaces with eased edges allow safe handling and clean, accurate fitting.
CLS vs Treated Sawn Timber
CLS is planed and kiln-dried for clean internal studwork and partitions. For outdoor or heavier structural work — fencing rails, floor joists, roof rafters and garden structures — you need pressure-treated sawn timber instead: see our treated timber (C16 & C24, 2x2 to 10x2). Browse the full timber & sheet materials range.
Delivery Information
Lead times are currently 3-5 working days to mainland UK addresses. Longer lengths are bulky items, so suitable delivery access is required.