Downstairs Shower Room

[Barney12]

I’m having a real brain fog moment with the layout of our ground floor WC/Shower.
The wastes are going to have to be in the slab so I’ll need to create a channel former so I can run the wastes. 
I’n my rather crude drawing below I’ve got a section of soil pipe that runs underground and then two separate wastes (50mm for the shower and 40mm for the basin) going to that stub (which will be below the slab level).

Or could I get away with extending the 50mm and 40mm wastes to just the one stack used by the toilet. The run would be circa 3.5m for the sink.

 

All this is going to be slab level so will be inaccessible so I want it to be right.

 

Input hugely appreciated.

[Ian]

@Barney12

I'd be tempted to go with the 2nd option and run the small diameter wastes direct to the WC soil stack. Could you not take a direct route to the WC stack instead of introducing 90 deg junctions?

[Barney12]

1 minute ago, Ian said:

@Barney12

I'd be tempted to go with the 2nd option and run the small diameter wastes direct to the WC soil stack. Could you not take a direct route to the WC stack instead of introducing 90 deg junctions?

 

Its an interesting point. I did think that but some some reason I have this thought that services should always run round the outside of a room. What that thought is based on though I'm not entirely sure  

[Ian]

14 minutes ago, Barney12 said:

...but some some reason I have this thought that services should always run round the outside of a room. What that thought is based on though I'm not entirely sure  

@Barney12 Maybe you're thinking of positioning electric cabling on a wall (no diagonals allowed there!)

Edited April 11, 2017 by Ian

[ToughButterCup]

Just a thought...  I expect I've missed something....

 

Each waste exits the house under the nearest wall and the foul  drain runs round the outside of the house. That means minimum  faff in or under the slab.

Ian

 

[Barney12]

6 minutes ago, recoveringacademic said:

Just a thought...  I expect I've missed something....

 

Each waste exits the house under the nearest wall and the foul  drain runs round the outside of the house. That means minimum  faff in or under the slab.

Ian

 

 

So are you saying you're even taking 32/40/50mm wastes outside through the nearest wall? 

If yes how are you then interfacing them to the 110mm soil pipe once outside?

Or are you taking a 110mm stub to every point?

 

(P.S. I like your logic though ref "faff")

[Nickfromwales]

Option 2 is fine, but I'd use 2 x 45* bends instead of 1 x 90* on each run. 

Youll be able to rod back from the shower to the soil with ease, and if you do the same at the invert for the basin you'll be able to back rod that all the way to the soil too. .