R502.4

Section R502.4 is titled 'Joists under bearing partitions' and covers the strength and arrangement of floor joists which support bearing partitions, both parallel and perpendicular to the joists. Joists supporting bearing partitions must be designed by calculations - the code does not provide prescriptive designs for this. Where the perpendicular bearing partition is offset more than the depth of the floor joists from the supporting girder, beam, wall, or partition which supports it, the joists must be calculated to determine they can handle both the floor load and bearing partition load. The purpose of this section is to provide structural stability.

The model shows:
•Joists grouped together supporting a parallel bearing partition;
•Separated double joists with blocking (with a pipe installed in between them) supporting a parallel bearing partition; and,
•Joists supporting a perpendicular bearing partition, which is moving to highlight the maximum offset from the beam below without needing joist calculations.