Steel Joists with slopes less than or equal to ½ inch per foot are selected directly from the joist tables. Steel Joists with slopes greater than 12" per foot are given the label XXGSP; they are not selected from the tables. The SJI manual indicates that the tables are only valid for slopes less than or equal to ½ inch per foot, so for those whose slope is between ½ inch per foot and 12" per foot, the program selects the joist size from the table and appends "SP" to the label to indicate that the actual design needs to be dealt with specially by the joist manufacturer.

In the selection of sloping joists from the tables, the length used is the actual length, not the horizontal projected length. The loads are used and shown on the Report are the vertical loads, applied perpendicularly to the joist. This is not consistent with the way loads are applied and shown for other beams in the program, but it is consistent with the way sloping Steel Joists are commonly designed. (For other beams, the perpendicular component of the vertical load is applied perpendicularly to the beam and the axial component is ignored; for Steel Joists the entire vertical load is applied perpendicularly to the joist.) This means that for Steel Joists the applied perpendicular load is greater than actual, to try to make up for the axial component which is not applied. This methodology is generally accepted and gives reasonable approximate designs, but the design of sloping Steel Joists should be verified by the joist manufacturer.