Ceiling Joist Support Beam Span

View joist rafter tables.

Ceiling joist support beam span.

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. Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters. It covers 2 common lumber species and sizes at 20 pounds per square foot load. Ceiling joist span use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size.

Simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12. Although 2 x 4 s are included in the official table they are not listed because it is never advised to use them. This ceiling joist span table is based on the 2012 irc for uninhabitable attics with limited storage. Sixteen inch oc spacing of ceiling joists made from 2 southern pine allows for a maximum 13 inch span length.

Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. 2 x 12 s are not listed because you can span pretty much whatever you want.