Roof Joist Span Table

Span tables use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.

Roof joist span table.

Simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12. Span calculator for wood joists and rafters also available for the android os. Joist and rafter span tables. For example the highlighted cell below shows that a 2 x 6 southern yellow pine joist with a grade of 2 and spaced 24 apart can have a maximum span of 10 feet 0 inches 10 0 if you are designing your structure to support a plaster ceiling.

Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters. If this is the case with your structure use the floor joist table to determine maximum joist length load. 1 inch 25 4 mm 1 foot 304 8 mm 1 pound per square foot 0 0479kpa. View joist rafter tables.

These 46 tables are based upon design values for visually graded southern pine dimension lumber that became effective june 1 2013. You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths. Tables listing maximum spans for southern pine joists and rafters are detailed below.