Ceiling Joist Support Beam Span

Large room joist spacing.

Ceiling joist support beam span.

Ceiling joist span use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size. View joist rafter tables. Sixteen inch oc spacing of ceiling joists made from 2 southern pine allows for a maximum 13 inch span length. It covers 2 common lumber species and sizes at 20 pounds per square foot load.

This ceiling joist span table is based on the 2012 irc for uninhabitable attics with limited storage. 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. Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters. 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.

Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. Although 2 x 4 s are included in the official table they are not listed because it is never advised to use them.