A squared timber (badding) is a heavy timber beam with a standard dimension of approximately 63 x 175 mm (2.5 x 7 inches), widely used in construction as a bearing beam, joist or stud. The term originates from traditional Dutch timber usage and refers specifically to this sizing.
Standard dimensions
| Name | Dimension (mm) | Application |
|---|---|---|
| **Squared timber** | 63 x 175 | Floor joists, roof structures, bearing beams |
| **Half squared timber** | 32 x 175 | Battens, lighter constructions |
| **Double squared timber** | 63 x 175 (2 pieces joined) | Heavy spans |
Where is squared timber used?
- Floor structures — as floor joists in timber intermediate floors
- Roof structures — as purlins or rafter legs
- Partition walls — as top and bottom plates in timber frame construction
- Temporary structures — scaffolding, formwork, shoring
Squared timber vs. other beam sizes
| Timber type | Dimension | Name |
|---|---|---|
| 38 x 89 mm | 1.5 x 3.5″ | Batten |
| 38 x 140 mm | 1.5 x 5.5″ | Plank on edge |
| **63 x 175 mm** | **2.5 x 7″** | **Squared timber** |
| 75 x 200 mm | 3 x 8″ | Beam |
Timber species
Squared timbers are available in:
- Spruce — inexpensive, suitable for interior applications
- Pressure-treated spruce — for exterior constructions (use class 4)
- Douglas fir — stronger and more durable, attractive appearance
- Oak — traditional, for exposed work
Tips for DIY
- Check whether the squared timber is planed or rough-sawn — rough-sawn dimensions are slightly larger
- For load-bearing structures, always choose structural timber with CE marking
- Account for the centre-to-centre spacing when placing floor joists: typically 400-600 mm
Related terms
- Beam
- Joist
- Purlin
- Timber frame construction
- Truss