Soil pipe in the way of flat roof joists, help!

[Kido44]

I am having a wall removed, due to a kitchen extension, and a flat roof fitted on the extension.
The soil pipe from the toilet runs in the way of where the steel will be going and the flat roof joists.
How can I get the soil pipe down through the steel, and the joists, without the fall being to great.
I will be getting a plumber out but I'm worried this is going to cause a major problem.

I have provided a pic, and I'd appreciate any help.

Thank you

//www.diynot.com/network/Kido44/albums/

 

[tony1851]

Did you get any plans dawn up? If so, whoever drew your plans should have detailed this.

 

[dann09]

1. Could you post a pic showing the whole rear elevation, and accurately mark on the pic where your proposed extension ceiling will meet the brickwork, and
where your proposed finished roof line is going to be?

2. How is the opening to the left supported? Maybe it's the pic, but i can't see a lintel?

3. Are you proposing any further knock-thru's?

4. In posted pics, perhaps you would move any paraphernalia or ladders out of the way?