Grades
Sawn timber products are categorised by grading rules. New Zealand Standard NZS 3631:1988 Timber Grading Rules is the official standard for grading timber in New Zealand. The standard divides all species into three groups: native softwood, hardwoods (New Zealand grown exotic and imported), exotic softwoods (New Zealand grown exotic and imported).
Timber graded under NZS3631 is classified into four categories:
• Appearance - For a clear finish or paint finish where
visual quality is important.
• Structural - For building purposes needing strength
and stiffness.
• Cutting - For remanufacturing, using clear lengths between
whorls of knots.
• Other - Not meeting the requirements of the other grades,
but complying with the general provisions of the rules.
End Uses
Examples of end uses for each grade are:
Clears
Long length clear timber for mouldings, turnery, furniture, joinery, panelling and exterior cladding.
Select A
Exterior joinery, stair treads and panelling.
Select B
For uses requiring one good face and two edges (eg panelling and shelving).
Dressing
Flooring, architraves, skirting, weatherboards, fascia, high grade decking and shelving.
Merchantable
Shelving, sarking, hidden framing for furniture and doors, fence palings and lower grade decking.
Cuttings
Used in short lengths for joinery, furniture and finger-jointing.
Engineering
Used in designed timber construction (eg beams and purlins).
Framing
General building construction (eg wall framing, trusses, joists, beams, bearers, rafters, lintels etc).
Box
Used for formwork in building construction and other temporary uses and packaging (e.g. pallets, crates, boxes, bins, etc).