AS 1684 - Code Compliance Overview
AS 1684 Residential Timber Framed Construction is a four-part Australian Standard covering design criteria, building practices, tie-downs, bracing and span tables for timber framing members. It is also referred to as the Timber Framing Code. By complying with this Standard, users are Deemed to Satisfy the requirements of the Building Code of Australia.
The National Timber Development Program (NTDP) developed the Standard for consideration by Standards Australia. This single reference publication for housing throughout Australia was published in December 1999. The Standard is subject to on-going review and amendments. Users of the Standard should ensure that they refer to the latest edition.
Amendments to AS 1684 prepared by the Standards Australia Technical Committee are completed based on feedback from users. AS 1684 now covers a wider range of acceptable practices with a greater number of technical explanations included in the latest amendments.
AS 1684 resources
Part 1 Design Criteria (AS 1684.1) - Part 1 sets out the basis for calculating timber sizes and forces to be resisted by tie-down and bracing. It provides a standard reference for designers and product manufacturers to produce engineering solutions compatible with AS 1684.
Part 2 Non-Cyclonic Areas (AS 1684.2) - Part 2 covers design and construction details for non-cyclonic areas. Four wind classifications are covered including N1, N2, N3 and N4.
Part 3 Cyclonic Areas (AS 1684.3) - Part 3 is similar to Part 2 except that it covers design and construction details for cyclonic areas. Wind classifications covered are C1, C2 and C3.
Part 4 Simplified / Non-cyclonic Areas (AS 1684.4) - Part 4 provides simpler design procedures than those contained in Part 2, for N1/N2 wind classifications only. On some situations it will provide more conservative solutions. The scope of Part 4, including house geometry and range of stress grades is also more limited.
AS 1684 User Guides
AS 1684 User Guide 1 - Nominal vs specific fixings - unless otherwise specified in the Standard, specific fixings shall be in addition to nominal fixing. Explanations and examples are provided.
AS 1684 User Guide 2 - Temporary bracing - information is provided on how to achieve temporary bracing requirements during the construction process.
AS 1684 User Guide 3 - Simplified tie-down details for coupled roofs - simplified tie-down details are provided for coupled roofs where nominal nailing alone is not adequate to resist the net uplift on the roof.
AS 1684 User Guide 4 - External wall heights - recommendations are provided for extending the use of the Standard to cover wall height up to 3600 mm.
AS 1684 User Guide 5 - Fixing of top of bracing walls - details are provided for fixing internal bracing walls to floor, ceiling or roof diaphragms.
AS 1684 User Guide 6 - Roof truss tie-down - this guide points out that AS 4440 does not specify tie-down requirements and that reference should be made to AS 1684 Parts 2 or 3.
AS 1684 User Guide 7 - Ridgeboard and hip rafter tie-down - acceptable practice is provided for the tie-down of ridgeboards and hip rafters.
AS 1684 User Guide 8 - Masonry anchor tie-down - tie-down capacity is the lesser of the fixing into the slab and the bearing strength of the bolt and washer in the bottom plate. Details are provides the uplift capacity for the bolt and washer in the bottom plate.
AS 1684 User Guide 9 - Fixing of bottom of hardboard bracing walls - this corrects an anomaly in AS 1684 regarding tie-down of hardboard bracing walls. For hardboard bracing walls rated at 3.4 kN/m, tie-down required is nominal fixing only.
AS 1684 User Guide 10 - Distribution of racking forces via diaphragms - information is provided on bracing methodology and recommendations for diaphragms.