By Northpine director Bruce Larsen
Since the Christchurch earthquakes, many Kiwi home owners and builders have become more focused on ensuring that all houses built from timber products have been tested, audited and passed as compliant with design standards.
But many people, including those in the timber industry itself, fail to realise that modern technology allows testing for each structural member and ensuring it is “fit for purpose”.
A study conducted by the Forest Research Institute in 1991 demonstrated, in essence, that the further north in New Zealand the timber comes from, the denser and stronger it is (see map and graph at right).
A further study by the FRI in 1997 then showed conclusively that visual grading — ie, using New Zealand grading rules No 1 Framing — gave different performance characteristics depending on which region the timber came from.
The results showed that out of the six regions tested, only two met the actual requirements that the visual grading was designed to achieve, one of these being Northland.
From its sawmill in Waipu, near Whangarei, Northpine specialises in producing large dimension beams and unusual-sized timber products, sold under the Northbeam brand and ideal for use where aesthetics are important to the “feel” of the building.
Specialist production runs target high quality Northland logs to produce beams and squares up to 7.2 metres long.
Products make visual statement
These individually verified products meet demanding New Zealand building standards and make a wonderful visual statement.
Northbeam structural timber is graded in process, then a sample is verified in a testing rig.
Here the sample is placed under immense strain to ensure that that batch of timber meets New Zealand Standard requirements.
This rigorous process is then audited by a third party (Graderight) to ensure that all measurements and systems are compliant.
Northpine and Northbeam structural timber products are manufactured from radiata pine grown in Northland — where the pine tree grows stronger, denser and stiffer.