You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
Wood floor joist span chart.
Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters.
Our joist span charts are for wood joists with a maximum dead load of 10 pounds per square foot and a live load of 40 pounds per square foot.
Simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12.
Joist span table use these tables to determine floor joist spans based on grade of lumber size of joist floor joist spacing and a live load of 30 lbs ft 2 or 40 lbs ft 2 these tables can also be used to determine deck joist span.
Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.
While every effort has been made to insure the accuracy of the information presented and special effort has been made to assure that the information reflects the state of the art neither the west coast lumber inspection bureau the american wood council nor its members assume any responsibility for any particular design prepared from this online span calculator.
This chart is for basic reference only.
If you have any questions.
Live load represents the weight of furniture snow etc.
View joist rafter tables.
Also available for the android os.