Structural timber is used for structural applications such as beams and framing. In New Zealand, grading methods include visual stress grading, machine stress grading, and acoustic stress grading of timber. Specialty timbers can be used for a range of structural applications under New Zealand's performance-based building code.
Structural timber species
Farm Forestry Timbers has determined the characteristic stresses for Farm Forestry Timber's No. 1 structural grade for a range of specialty timber species, so engineers can use them in structural design. The species include macrocarpa, lusitanica, lawsons cypress, totara and redwood.
Note: For structural use inside the building envelope, untreated cypress (including leyland, macrocarpa, lusitanica and lawsons) heartwood meets the durability requirements of NZS 3602.