View joist rafter tables.
Floor joists timber framing span tables.
These span tables assume installation of at least three joists or rafters that are spaced not more than 24 on center.
Floor joist span tables for various sizes and species of wood 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.
Also available for the android os.
Simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12.
Next use the buttons in the table to select the maximum length in feet or metres in brackets that your floor joists must span.
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.
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.
Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.