wetroom form waste to 110mm

[nick9one1]

I'm converting an en-suite to a wetroom with a preformed tileable tray.

Behind the stud there is already a 110mm waste used by the sink and toilet, it is capped on the right and exits on the left.
The shower waste is 40mm, but as its below the floor I will need to join the 110mm in the side. I can't go into the top like the sink.
Is this likely to cause a problem if there is a toilet blockage coming back up the shower drain?
Any thoughts?

 

[robinbanks]

Is that a double branch? How high is the vertical section of soil pipe underneath that branch? (Or is it a single branch, lying down? That's a bit nasty if it is..)

 

[nick9one1]

The toilet is just tee'd off the horizontal. There is another tee on the left, with a Durgo about 5ft high,

 

[robinbanks]

Hmm. If that were mine I'd have looked at turning the toilet left and into its own connection to the stack, with the sink/shower on a branch below

 

[Hugh Jaleak]

I'd seriously look at getting rid of the 110mm pipework past where the WC connects, and run a separate waste for the shower directly to the stack. That setup to me is asking for trouble.

 

[nick9one1]

Thanks for the replies. It's been in 20+ years and hasn't caused a problem (yet). But will definitely change it if more knowledgeable people than me think its a bad setup.

Just to make sure I understand.

Rotate the pan connector 90 degrees so it will tee into the stack slightly higher.
Remove the horizontal 110mm branch the toilet sink and shower currently connect to.
40mm shower waste will tee into the main stack below the pan connector.
34mm sink waste into the shower waste? or also run all the way to the stack?

 

[Hugh Jaleak]

Simplify things. Change the Junction on the Horizontal section for a Bend, (or cap it off as close to the junction as you can.) Keep this dedicated to the WC. Avoids 'dead' section upstream of WC connection where waste could accumulate.

Ideally run separate wastes for shower and basin, or run in 50mm from where they join, but if you do connect both to same 40mm run, just be aware basin could pull the shower trap.

 

[nick9one1]

If I keep the WC on the current horizontal section, there won't be anywhere for the waste shower to connect (other than to the same horizontal 110mm). That's why I thought to create another tee
Also hindered by two rad pipes crossing over the horizontal.

 

[nick9one1]

On second thoughts, putting the WC on its own connection to the stack, capping the original pan connector, but keeping the horizontal would require the least work.

 

[Laurieo]

WC on its own connection and two reducers into the T for shower and sink .

 

[Hugh Jaleak]

Given how little room you've got, I'd suggest for ease, cut as close to WC connection Junction as you can, fit a collar, then double waste adaptor, e.g. https://www.drainageshop.co.uk/110mm-pushfit-soil-system/110mm-double-waste-adaptor-40mm40mm.html