Report: Pathways to Building Code compliance for farm-totara timber
Sustainable Forest Solutions
Clause B1 Structure
The author wishes to acknowledge the support from the organisations and individuals that have enabled this project to be undertaken. These include; the Ministry for Primary Industries (through the Sustainable Farming Fund), Tane’s Tree Trust and the New Zealand Farm-Forestry Association, (including the Indigenous Forestry Section), the Northland Totara Working Group members Paul Quinlan and David Bergin for assistance in finalising this report, Michael Hayes & Geoff Cookson, for their time and donated sample boards of timber for testing, and saw-miller, Shane Hyde, for his time and the use of his band-saw in re-sizing some of the timber samples. The time and input from Robin Curtis, CEO of NZ Sustainable Forest Products, is also acknowledged and much appreciated.
In producing this report, reasonable care has been taken regarding the accuracy of the information presented. However, no guarantee as to the truth, accuracy or validity of any of the comments, implications, recommendations, findings or conclusions are made by the author, the Northland Totara Working Group, Tane’s Tree Trust, or any other party. Therefore, neither the authors, nor any of the supporting organisations, shall not be liable for, or accept any responsibility for, any loss, damage or liability incurred as a result of direct or indirect result of any reliance by any person upon information or opinions or recommendations expressed in this work. Users of any of this information, whether contained or inferred, in or arising from this report do so at their own risk.
Performance requirements around loads that buildings are subject to is set by Building Code clause B1 Structure, to ensure buildings are stable and withstand physical conditions.
For structural timber Compliance Document B1 requires
- NZS 3603 as the Verification Method (i.e. Prescriptive tests or calculating methods) or
- NZS 3604 as the Acceptable Solution (i.e. Prescriptive step-by-step methods).
NZS 3604 timber framed buildings only applies to radiata pine and Douglas fir, so an acceptable solution is not available for farm-totara to be used for structural applications. However, Characteristic Stresses have been determined for Farm Forestry Timber's No. 1 structural grade and thus can be used as a verification method for farm-totara timber to comply with the building code under NZS 3603 Timber Structures Standard.