Table 6
FLOOR JOISTS – May support loadbearing walls perpendicular to joists
AS 1684.2 — Cl. 4.3.2
Single & Upper Storey
Figure 4.9 — Floor joists
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Wind classification
Timber grade
Roof type
Span condition
Joist spacing
Roof load width (RLW)
Table 6 — Floor Joist spans
| Size D×B (mm) | Max span (mm) |
|---|
Table 6 — Notes
- Maximum floor joist spans supporting roof loads are based on sheet roof 40 kg/m², tile roof 90 kg/m² (incl. framing and ceiling), and flooring 40 kg/m².
- A roof load width of “0” shall be used for floor joists not supporting roof loads.
- The sizes given are not suitable where heavy point loads (other than those allowed by Cl. 4.3.2.4) are supported within the joist span.
- For lower storey of two-storey construction, floor joists shall not support roof or upper floor loads within their span.
- Where joist ends do not support roof loads, the joist may cantilever 25% of the allowable single span, not exceeding 50% of the actual backspan.
- Joists crippled over supports shall be considered as single span joists (Cl. 2.7.5.4).
- Where D/B > 4, lateral restraint may be required (Cl. 4.2.2.3).
Disclaimer: This calculator references span tables from AS 1684.2 Supplements (2010). Results are for guidance only and must be verified by a suitably qualified engineer or building designer against the current edition of the Standard and project-specific conditions. Structopedia accepts no liability for errors or omissions.