Roof Joists Span Tables

The tables below give maximum spans for rafters and beams.

Roof joists span tables.

Notches are not to exceed 0 125 of the depth of the joist and are to be located between 0 07 and 0 25 of the span from the support. Span calculator for wood joists and rafters also available for the android os. For lesser grades spans should be shorter. Straight line interpolation shall be permitted for intermediate spans and design values.

The calculated spans assume fully supported members properly sheathed and nailed on the top edge of the joist or rafter. Design properties 16 floor span and load tables 17 allowable holes 18 roof span and load tables 19 cantilevers 20 21 framing connectors 22 23 section 3. If this is the case with your structure use the floor joist table to determine maximum joist length load. Joist and rafter span tables.

Span tables for ceiling joists to bs 5268 7 3 span tables for flat roof joists to bs 5268 7 2 imposed loads of 0 75 kn m for maintenance and snow load are applicable where there is no permanent access no fixed ladder or staircase and most areas where the altitude does not exceed 100 metres refer to bs 6399 3. Also available for the android os. These span tables assume installation of at least three joists or rafters that are spaced not more than 24 on center. Design information for all joists tji joist floor framing 24.

The figures are based on quality materials. Joists rafters simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12. View joist rafter tables. Joist span tables use these tables to determine lengths sizes and spacing of ceiling joists.

These span tables apply only to flat roof and roof with a slope of up to 10 degrees. You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths. For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2. Roof span and load tables 12 13 framing connectors 14 15 section 2.

Keep in mind that these are maximums in other words shortening spans slightly will result in a more solid structure. Ceiling joists of the first floor of a two story structure often serve as floor joists for the second floor.