Residential timber-framed construction
The deemed-to-satisfy bible for timber-framed houses: bracing, tie-down, span tables.
Overview
AS 1684 is the standard most residential carpenters work to daily. It comes in several parts: Part 2 (non-cyclonic), Part 3 (cyclonic), and Part 4 (simplified, lower wind). Each contains span tables, bracing schedules, tie-down requirements and connection details. If your house meets the geometric limits and uses standard timber sizes, AS 1684 alone is your structural design.
Key Requirements
- Geometric limits on building width, ceiling height, roof pitch, etc.
- Span tables for floor joists, ceiling joists, rafters and lintels.
- Bracing schedule based on wind classification.
- Tie-down details from roof to footings.
- Connection requirements at all levels.
How it's used in the NCC
Called up by Part 6 of the Housing Provisions as a deemed-to-satisfy pathway for timber-framed Class 1 and 10 buildings.
Practical Notes
- Bracing units must be in the correct walls and directions — not just any wall counts.
- Tie-down is often where inspectors find issues, especially at hip and gable ends.
- If the building exceeds AS 1684 geometric limits, you need engineered design to AS 1720.
Where to obtain
The full text of AS 1684 is published by Standards Australia and must be purchased — typical price A$150–400 per part. Always work from the current edition referenced in the NCC, not an older one.