2) For design parameters, refer to figure 7.26. View Joist & Rafter Tables. Pergola Rafter Spans for 600 mm and 900 mm Spacing. Listed are 46 tables based on common loading conditions for floor joists, ceiling joists and rafters. Span tables allow users to choose an appropriate size and stress grade to achieve spanning needs. Wind Classification N1 & N2. Internal Floor Joist Spans for 450 mm and 600 mm Joist Spacing Single Span Joist Spacing 450 mm Joist Spacing 600 mm Treated Pine Span Tables. AS1684.2 and 3. Span Tables F7 Rafters A maximum roof pitch of 25 degrees is assumed. Notes: 1) Refer to general notes for information that is relevant for all span tables. • Readily available preservative treated against borers and termites. Headers & Beams Simplified maximum span tables for selected visual and mechanical grades of Southern Pine lumber in sizes 2×4 thru 2×12. Stress grades and timber sizes combine to determine the spanning ability of load carrying members. For simple construction, such as domestic construction, this can be determined from span table supplements in AS1684.2 and AS1684.3. The following table provides an easy comparison of popular seasoned softwood grades and sizes for joists in residential domestic internal floor applications.