Roof Joist Span Table
If this is the case with your structure use the floor joist table to determine maximum joist length load.
Roof joist span table. These 46 tables are based upon design values for visually graded southern pine dimension lumber that became effective june 1 2013. Joist and rafter span tables. Table r802 4 1 ceiling joist spans for common lumber species uninhabitable attics without storage live load 10 psf l δ 240 check sources for availability of lumber in lengths greater than 20 feet. 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.
You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths. Span tables use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads. Tables listing maximum spans for southern pine joists and rafters are detailed below. 1 inch 25 4 mm 1 foot 304 8 mm 1 pound per square foot 0 0479kpa.
For each application a pdf download is available. Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters. View joist rafter tables.