Shower waste water configuration

[JobsfromtheMrs]

Hi
I'm currently doing the pre-planning for my next DIY project fitting a shower tray and enclosure from scratch. I'm confident of being able to do the job but not being a plumber not sure the best way to go about it so would appreciate any advice.
The current upstairs room has a black waste water pipe running between the joists from one end to the other where it then drops downstairs. There is currently a sink plumbed into a boss on the toilet pan connector at the start of the run. This then feeds into the start of the black waste pipe. I want to add a shower tray and plumb the waste water into the same black waste pipe just before it drops downstairs so this will be downstream of the toilet. Because I only have the depth of the joist with which to connect the shower tray waste into the black waste pipe i don't have room for it to connect into the top of the black waste pipe. Can I add a 40mm pipe boss and connect into the side of the black waste just above centre? Also is having this connection downstream of the toilet going to pull the shower trap when the toilet is flushed. Thanks in advance

 

[SimonG]

Pictures would make so much more sense.

 

[JobsfromtheMrs]

When we had the extension built a few years ago the plumbers put this solvent weld in there ready for a bath waste or whatever but is now completely useless and in the way so will just have to cut it down and put a plug in it as its solvent welded. I'm thinking of putting a new collar to the left of it then putting a flexi hose between the trap and the collar. I've put the trap in the photo to show the depth and yes those wires will have to be moved.

 

[Deleted member 120897]

Hard to tell from photo, but the soil connection looks like push fit, so could that be turned towards the shower trap?

 

[JobsfromtheMrs]

Hard to tell from photo, but the soil connection looks like push fit, so could that be turned towards the shower trap?

Unfortunately not it's been welded.

 

[Deleted member 120897]

Don’t use a flexi. Personally I’d cut the section and use a bossed pipe connector.

 

[JobsfromtheMrs]

Can the connector come out of the side of the waste as not enough clearance out of the top.

 

[Deleted member 120897]

Yes it can come out of the side

 

[ShaunCorbs]

The whole soil pipe Chris means not the boss so you should be able to move it with a strap wrench

 

[JobsfromtheMrs]

Thanks Shaun. I didn't want to force it round as thought it was solvent welded as per the others, but a bit of a strong arm and it has indeed twisted round. Many thanks