These tables can also be used to determine deck joist span.
Floor joists timber framing span tables.
Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters.
These span tables assume installation of at least three joists or rafters that are spaced not more than 24 on center.
Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.
You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
The calculated spans assume fully supported members properly sheathed and nailed on the top edge of the joist or rafter.
To use the joist span calculator below first select the species of lumber you will use for your construction project from the drop down list.
Span calculator for wood joists and rafters also available for the android os.
Straight line interpolation shall be permitted for intermediate spans and design values.
View joist rafter tables.
Also available for the android os.