What is wane in timber?
Wane is the part of a sawn beam or board where the original rounded outside of the log is still present, so the arris is not sharp and square. Sometimes bark is still attached. Wane occurs when timber is sawn close to the outside of the log.
Why does wane matter?
- Reduced section: the rounded corner means the effective cross-section is smaller than the nominal size, slightly reducing strength and stiffness.
- Less bearing and fixing surface for boards, sheathing and connections.
- Sapwood and bark: the edge is mostly sapwood, which is less durable in many species. Retained bark holds moisture and attracts insects.
- Grading: visual strength grading rules limit the amount of wane allowed per grade, for example BS 4978 in the UK and NEN 5499 in the Netherlands.
In practice
- Structural timber: check on delivery that joists and studs are within the wane allowed for the grade ordered, and reject pieces that exceed it.
- Position it sensibly: put the waney arris on the least stressed or least visible side, with a full fixing face where boards are attached.
- Always remove bark before use.
- Use it deliberately: for rustic cladding, garden timber and furniture, waney edges are a feature. Use durable heartwood or protect the sapwood.
- Buying: square-edged timber costs more than waney-edged boards but saves waste on precise work.
Related terms
- Sapwood
- Bark
- Wood species
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