Four sides clear, free from sapwood, sound knots up to 10 mm allowed.
Not allowed: Sapwood, rotten, cross grain, mould, cracks, bark, insect, middle pith.
Allowed – sound knots up to 30 mm, healthy knots up to 80 mm, hard, healthy middle pith, sapwood up to 25% of board width.
Not allowed: Sapwood, rotten, cross grain, mould, cracks, bark, insect, middle pith.