Square-edged timber is timber sawn flat and square on all four faces, so that it has sharp, straight arrises and no wane — the rounded original surface of the trunk, often with bark still attached. The Dutch term is meskant, literally “with an edge like a knife”.
Square-edged, wane and sawn timber
| Term | Meaning |
|---|---|
| Square-edged | Four flat faces, sharp arrises, no bark or rounding |
| Wane | The remains of the rounded trunk surface along an edge |
| Sawn | Cut to size, but may still carry wane |
| Planed | Machined smooth after sawing; the finished size is then a few millimetres smaller |
Structural timber from a timber merchant is normally square-edged. Rough-sawn beams and boards may contain wane — check this if the dimension is critical.
Why it matters
- Design cross-section — an engineer calculates with the full cross-section; wane reduces it and weakens the member, particularly at the bearing
- Fit — square-edged timber sits flat against sheet material, battens and other members; wane leaves gaps
- Durability — bark and sapwood beneath the wane are especially vulnerable to fungi and insects
- Strength grading — in visually graded structural timber, the amount of wane permitted is limited per grade
In practice
- When ordering for structural work (floor joists, rafters, purlins), specify square-edged material explicitly
- For garden timber and fencing, wane is sometimes chosen deliberately for its rustic look — but remember that this edge is the first to rot
- If you rip a beam down yourself, keep the edges square: a skewed edge gives a skewed bearing and therefore point loading
Related terms
- Timber
- Structural timber
- Squaring
- Wood species
- Wane
- Sawn timber
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