UK Timber Sizes — Sawn & Planed
When you order timber in the UK, the size quoted is usually the nominal sawn size. Planed (PAR — Planed All Round) timber is smaller because material is removed during machining. CLS (Canadian Lumber Standard) timber has rounded edges and its own set of dimensions. This reference shows all three formats side by side.
Sawn vs Planed (PAR) Sizes
Planing typically removes 3–5 mm from each face. The table below shows the most common UK softwood sections.
| Nominal Sawn Size (mm) | Actual Planed / PAR (mm) | Common Use |
|---|---|---|
| 22 × 50 | 18 × 44 | Battens, light framing |
| 22 × 75 | 18 × 69 | Battens, shelving supports |
| 22 × 100 | 18 × 94 | Shelving, light framing |
| 22 × 150 | 18 × 144 | Shelving, cladding |
| 25 × 50 | 21 × 44 | Battens, trim |
| 25 × 75 | 21 × 69 | Trim, light structural |
| 25 × 100 | 21 × 94 | Shelving, general joinery |
| 25 × 150 | 21 × 144 | Shelving, furniture panels |
| 38 × 50 | 34 × 44 | Framing, studwork |
| 47 × 50 | 43 × 44 | Studwork, floor joists (light) |
| 47 × 75 | 43 × 69 | Studwork, noggins |
| 47 × 100 | 43 × 94 | Studwork, floor joists |
| 47 × 150 | 43 × 144 | Floor joists, rafters |
| 47 × 200 | 43 × 194 | Floor joists, ridge boards |
| 47 × 225 | 43 × 219 | Floor joists, lintels |
| 75 × 150 | 69 × 144 | Posts, beams, heavy structural |
CLS (Canadian Lumber Standard) Sizes
CLS timber is commonly used for stud walling and partition framing. It has rounded (eased) edges and comes in specific sizes that differ from standard UK sawn.
| CLS Actual Size (mm) | Nearest UK Sawn Equivalent | Common Use |
|---|---|---|
| 38 × 63 | ~38 × 63 | Light partitions, ceiling battens |
| 38 × 89 | ~38 × 75 to 38 × 100 | Standard stud walls (non-load bearing) |
| 38 × 140 | ~38 × 150 | Load-bearing stud walls |
| 38 × 184 | ~38 × 175 to 38 × 200 | Floor joists (light), deep walls |
Standard Stocked Lengths
| Length (m) | Length (ft approx) | Availability |
|---|---|---|
| 1.8 | 6' | Common (fencing, short projects) |
| 2.4 | 8' | Very common (standard stud height) |
| 3.0 | 10' | Very common |
| 3.6 | 12' | Common |
| 4.2 | 14' | Available to order |
| 4.8 | 16' | Common for joists |
| 5.4 | 18' | Special order; limited sections |
Related Calculators
- Timber & Board Calculators — calculate board feet, linear metres, sheet goods and cutting lists
Actual planed dimensions can vary by ±1 mm depending on the timber merchant and machining tolerances. Structural timber is graded to BS EN 14081 (typically C16 or C24). Always verify sizes with your supplier, especially for structural applications.