Reconfiguring 2 X toilet outlets and 1 X bath outlet

[Tff123]

Preview​

Hi
I need to move my existing external toilet and bath outlets due to having a rear extension built and they foul the roofline.
After advice / opinions on my preferred option which I have included as a sketch.
My main concern is:
1, If I'll need air admittance valves and where they need to be positioned - if I do need them.
2, And whether it would ok / advisable to connect the bath outlet to the proposed toilet outlet....
Just to confirm the existing soil stack is vented correctly above roof level.

Any help / advice / criticism gratefully received.
Cheers Tony

 

[Ben-gee]

That looks fine, won’t need aav.

I would not connect the bath waste into the toilet outlet unless you can use a short boss pipe with the boss on the top of the ‘horizontal’ 4” ie don’t connect into the side of this pipe.
I suspect this may be too high for the bath waste , in which case run it separately and boss into stack lower down.

 

[exedon2]

No need for air admittance valves if stack is correctly vented.
Maybe look at using a access bend where it turns into stack give some rodding access.
I would personally connect the bath waste into the soil stack unless you could get bath connection into top of toilet float which would make bath waste unusually high.

 

[Tff123]

Thanks for the replies. Glad you both agree no aav required.
Good tip about providing access bend - thank you.
I'm really struggling to get the bath waste directly into the stack - but agree not a good idea to connect into the horizontal 110mm soil pipe after the toilet.
But I have thought about the below:

110mm Single Waste Adaptor 40mm | Drainage Shop

110mm Single Waste Adaptor 40mm available at The Drainage Shop. Buy Online Free Delivery Over £75. We cannot be beaten on Quality or Price.

www.drainageshop.co.uk

I've attached another quick sketch showing where it could go - apologies for the back of *** packet look....
Appreciate not really designed for this but your thoughts appreciated on it as long as it's a good secure fit.

 

[Knappers]

Can you take it through ensuite and outside wall then into stack?
If it needs a vertical drop outside you should consider going up a pipe size and/or including a vent pipe (bit old school)

 

[Tff123]

Can you take it through ensuite and outside wall then into stack?
If it needs a vertical drop outside you should consider going up a pipe size and/or including a vent pipe (bit old school)

Can't really do that as just not enough room in the WC unit due to the required 110mm junctions, the toilet outlet levels, and the proximity of the outside stack.
Could this work instead:

Viva 90° Flexible Pan Connector Inc Pipe Boss

SLINKY-FIT Pan Connectors are a very flexible pan connector which have a wire reinforced giving them strength and stability in the most flexible situations. They also have a Smart-Flo design extension tube which helps to prevent any sediment build up which could cause a future blockage.• 1¼" top...

www.toolstation.com

 

[Knappers]

What about original plan with 135° branch for bath and single waste adapter, angled up as much as is practical.
Think that's my best stab without more major work but still not loving it

 

[Tff123]

Yeah agree - not ideal but options limited. Only saving grace is pipework is easily accessible so if any problems fairly straightforward to resolve - hopefully!
Why do you prefer the 135 branch with single adapter in the middle of the bathroom run as opposed to the same adaptor at the end of the ensuite run?
Added to sketch if I've got your idea right.... There is enough room as sketch not to scale

 

[Knappers]

I guess it doesn't make any difference really, just to keep solids away from 40mm

 

[Tff123]

I guess it doesn't make any difference really, just to keep solids away from 40mm

Cheers Knappers - grateful for your input

 

[Knappers]

Less joints in the pan connector option so that has merit.
TBH I recon if it were my job and I had to guarantee the work, then I'd find a way to get it outside.

 

[Tff123]

Yeah fair comment - understand your thinking.
Cheers mate

 

[Knappers]

Goodluck