loft conversion step to overcome with bath/shower waste

[harrylime]

I am in the middle of a loft conversion. On each side of the bathroom, rsj steels run the length of the room, creating a 3 to 4 inch step on each side, over which I need to run the waste pipes. I would like to fit a bath and separate shower although I may need to compromise and fit a shower/bath. Any ideas how to overcome this obstacle? Raising the bath and shower on plinths is tricky due to restricted height of sloping ceilings. Would appreciate any thoughts. I am not a plumber so may be missing something obvious

 

[SimonG]

Drop below and box in.

 

[Plumbus]

Very similar question posed in L3....

 

[stevetheplumber]

can you not get out under the steels ?theres usually a gap the depth of the old ceiling joists run in that space straight out through the eaves and into the stack