scope:

This New Zealand Standard establishes visual grading rules for the selection of timber into quality classes. The four types of grades specified are: appearance grades, for finishing and other uses; cutting grades, for short clear lengths; structural grades, primarily for strength and stiffness; and box grades. For approval of species and grades for particular building applications refer to NZS 3602.

This Standard applies equally to green sawn, dried or machined timber.

Structural grade shall be comprised of specially selected timber for use in designed timber construction as distinct from light timber frame construction for which specific design is not required. The permitted defects are limited with the intention of ensuring that each piece can be assigned the basic working stresses and moduli of elasticity given by NZS 3603 for the appropriate species and condition.