Bathroom waste pipe fittings help

[Ali]

*Not a plumber, but can usually make things work out OK with a bit of guidance...however this also needs to satisfy the building inspector.

In my upstairs bathroom I've got toilet, basin and bath waste all along one wall as below.

The current arrangement from outside (really old photo, it's what I've got to hand - you get the idea, everything is in the same place)

Previously the bath and basin exited straight through the wall into their own downpipe to a gulley and met the soil pipe under the ground. The main soil stack was almost directly behind the toilet. With a new extension being built the drains are being re-laid, the main soil stack will be re-located to allow for a downstairs toilet. So I now need to re-plumb the bath and basin upstairs to somehow meet the new soil stack. The new 110mm pipe will be boxed into the new roof.

I'm trying to get my head around how to do this, I've seen these things -

Are they designed to allow bath / basin waste to drain into the pan connector, or is that just a vent? (The Screwfix website describes them as 'Universal Vent' but the McAlpine website just says 'Universal boss'

I can't see emptying a bath into one of those working out well, and it would be too high anyway.

Do I just run a second 40mm pipe outside meeting up with the main soil stack lower down? Now I think about it, this seems like the sensible way and it can all be boxed in anyway.

I do remember the drain guy I had round to map everything out saying it would be a good idea to have a rodding point inside for the toilet - I can't find any toilet connectors specifically saying they have access for rodding, but presumably you could rod through one of these universal vent / boss arrangements. I'll probably end up changing the pan connector anyway, so I could just get one of these.

 

[Ali]

Perhaps on the outside in a larger diameter (70mm?), maybe with rodding access at the bath end.

 

[Jaeger_S2k]

You will probably have vacuum issues with the red lined drawing.
The loo will vacuum the bath and basin traps (it'll get smelly) and the bath will vacuum the basin trap, more smelly.

I'd leave loo as is with new fittings, no need to vent the loo the open stack does that. The fitting you mentioned, I'd leave off, you don't need a vent and you won't be able to rod through it.
Is there not a face plate near the bottom of the vented stack, what is the distance from base of stack to manhole?

I'd recommend a standard 40 mm trap, for the bath and the HepVo self sealing waste valve 32mm for the basin.
Does away with any venting problems and are fully approved by BC. Shop around they've become quite expensive, these are brilliant for under shower trays with flow issue and venting problems, they are a dry trap.

Take them out together to the outside in 40 mm, but not to the open collector. I'd enter the stack with a 40 mm adapter and keep it all sealed.

 

[Jaeger_S2k]

I'm not even sure I'd put a rodding access to the 40 mm, but if wanted fit a equal T outside with a welded access cap, like this pointing to the bath

you would fit it like an elbow, sept profile coming from the bath to the stack, the other tail takes a plug with screw on access.

 

[gaz1]

toilet keep the same just get a pan connector

as goes for sink and bath no point running into the soil stack run them towards the hopper

bath one will be too low for the pan connector anyway

alternative run the sink into the bath but you will need anitvac traps on both sink and the bath with 2 seperate pipes no need for antivac traps on sink or bath

building inspector wont bother as no change to original pipes that was used before

 

[Jaeger_S2k]

Not good practice to run soiled water into an open collector, actually illegal in Scotland.
Encourages smells at both the open collector and the open gully at ground level, scummy soapy water never is a good look. If you have the bubble bath ladies, that can cause a foamy backfill in both too. There are no good reasons to be lazy.

There is no need for a HepVo on the bath, the basin, not the sink, will act as an automatic air admittance valve for the setup.

Soil stack is being relocated, BC will be on this like a cheap suit.

Why core drill 2 holes when 1 will suffice?

Are you doing the internal services yourself, @Ali?

 

[gaz1]

now since ive reread the post

my error on the previous post as hadnt read its internal and will be within the roof void of the extension, except for connecting to the pan connector

for start off you will only beable to pipe the sink into the pan connector as the bath waste pipe is too low to connect into it

so that means you will need to run a pipe to the soil stack and use a boss strap around the soil pipe

so back to the fitting of the soil pipe

run the upstairs toilet towards the new stack place at this point its fit a soil tee as you need an air admitance valve above the tee
pipe over both the sink and bath towards the stack

you have 2 choices here run as one pipe or run as 2 waste pipes with one pipe you need antivac traps on both the bath and sink wastes 2 pipes dont need it you will also need to strap/support both pipes as they do sink with hot water rather well when in use

then connect into soil stack with boss strap/s

 

[iNf]

It would be easier to give advice if we know where the extension is going and the proposed new location of the stack.

 

[Ali]

Not good practice to run soiled water into an open collector, actually illegal in Scotland…

Yes, as mentioned it will be in the roof void so must be enclosed, unlike the current setup

Are you doing the internal services yourself, @Ali?

Yes, drainage contractors will lay the underground pipes and I will do everything above ground (all under the watchful eye of BC). I’m getting my head around it now, I was off to a false start as I was thinking it would be necessary to run internally for maintenance access, but I’m pretty sure I can run a tee at the bath end with an access cap like you mention, and put an access panel in the wall where it’s boxed in.

It would be easier to give advice if we know where the extension is going and the proposed new location of the stack.

You’re quite right, and I’ve also got some questions about the drainage for the proposed downstairs loo so I’ll do a proper layout next time I’m at a PC.

Thanks for all the tips.

 

[Jaeger_S2k]

If the stack relocation is within the roof void, then @gaz1 is correct, an "elephant foot" AAV will be needed, but you don't mention if that's the case.

Would be nice to see plan and elevations of services plans for a better understanding. Already assumptions are being made, that contradict each other, you're red line plan locates the stack on the exterior wall and wouldn't make sense to come back to an internal termination.

 

[gaz1]

now im going to give you something to think about



with the pic above if your going full width of the back with an extension then place the soil stack to the left of the pic where the doorway is

you can do it with very little change there as there is already a drain there and that also means its external piped

now with this being done all bathroom pipes can be run to the left instead of the right within the pic

with it running that way everything is external no need for air admitence valve either and you can also still use the original soil stack thats been moved forward but thats on how deep the original soil and underground pipework is or you also run that external too

that means you can reuse the old soil stack as run off water collection or which might be the case of you for another kitchen area further forward in the new extension part

i havent seen your plans i dont know the depth of your original drains these are the things you need to know and drainage of the council will want to know these details

this also means you can play around with the bathroom rather well

my drawing to the right

toilet and sink can be swaped around but also gives different ways for connections to the outside soil pipe

its your bathroom you know the sizes which you need but the closer that toilet is to a soil pipe the better but remember this that soil pipe can exit down the side of the house and connect into the soil stack down the side of the extension

which removes any pipework within the extension with replanning the downstairs rooms you can have the dowstairs toilet at side of the house

if you intend to keep the new toilet where it is just fitting an air admitence valve near the new toilet is ample enough

the upstairs bathroom will go to the new side soil stack and external side drain which also collects water from the top house gutter new pipe to the drain

the extension is refed with a new drain for roof water and if you intending a new kitchen in the new extension

 

[Ali]

now im going to give you something to think about

View attachment 501759

with the pic above if your going full width of the back with an extension then place the soil stack to the left of the pic where the doorway is

you can do it with very little change there as there is already a drain there and that also means its external piped

now with this being done all bathroom pipes can be run to the left instead of the right within the pic

with it running that way everything is external no need for air admitence valve either and you can also still use the original soil stack thats been moved forward but thats on how deep the original soil and underground pipework is or you also run that external too

that means you can reuse the old soil stack as run off water collection or which might be the case of you for another kitchen area further forward in the new extension part

i havent seen your plans i dont know the depth of your original drains these are the things you need to know and drainage of the council will want to know these details

this also means you can play around with the bathroom rather well

my drawing to the right

toilet and sink can be swaped around but also gives different ways for connections to the outside soil pipe

its your bathroom you know the sizes which you need but the closer that toilet is to a soil pipe the better but remember this that soil pipe can exit down the side of the house and connect into the soil stack down the side of the extension

which removes any pipework within the extension with replanning the downstairs rooms you can have the dowstairs toilet at side of the house

if you intend to keep the new toilet where it is just fitting an air admitence valve near the new toilet is ample enough

the upstairs bathroom will go to the new side soil stack and external side drain which also collects water from the top house gutter new pipe to the drain

the extension is refed with a new drain for roof water and if you intending a new kitchen in the new extension

View attachment 501763

Thanks Gaz, but steady on - all the drawings, planning, building control are complete and it’s not changing now! I’ll upload some proper drawings of what’s happening later. I’m definitely not rearranging the bathroom anyway.

As said, my fault for not giving the full picture.

 

[gaz1]

its not that your doing away with that left drain anyway

digging down and changing its direction is worth it more so to have 2 uses on the side of the house as you can add both soil pipe and also a rainwater pipe to the rear of the property there

as goes for the internal toilet simple just plumb it in and vent it in the toilet room is all thats needed

its an easy change and planning will except it

 

[Ali]

OK, I think I've made sense of the upstairs bathroom.

(Hopefully it's obvious that everything below the roofline of the extension's pitched roof will be internal & boxed in.)

What's this about an 'Elephant's foot' though?

 

[Ali]

I also need to work out what to do for a small basin in the new downstairs W/C. The layout looks like this, so you can see why I'm moving the soil stack now -

N.B. Surface water is sorted, it's all separate from foul.

I'm not sure whether to go towards the toilet with the basin waste, towards the soil stack, or put in it's own 100mm connection underground and then come straight up. It could be boxed in at low level but the room is only about 1m wide already. I think I need to do a bit more figuring out in this room as I might be able to hide it within some shelves or a small cupboard to the RH side of the basin.

 

[gaz1]

if you come through that roof with the soil you will regret it as it will leak over time as they always do

now since your going to remove this gully in red you can change it to a soil pipe and also go through the extension side to the side of the property as long as theres no garage down the side of the house if so ignore

however what i will say is you can change that gully into a soil pipe and box up on the left side its an easy change from a gully to soil pipe

as the soil runs that way you can also boss strap into the top of the soil pipe with both the sink and the bath in blue there original holes coming out of the wall

fitting 2 offset soil elbows at the side of the extension wall will bring the soil pipe external and therefore you can run it up the side of the house



at a guess this is how your pipes run purple is the gully to the main drain this gully pipe can be moved down the side of the house and a new soil pipe up the side of the house

whilst fitting a tee you can then rod it but you wont need to do

 

[Ali]

if you come through that roof with the soil you will regret it as it will leak over time as they always do

now since your going to remove this gully in red you can change it to a soil pipe and also go through the extension side to the side of the property as long as theres no garage down the side of the house if so ignore

however what i will say is you can change that gully into a soil pipe and box up on the left side its an easy change from a gully to soil pipe

as the soil runs that way you can also boss strap into the top of the soil pipe with both the sink and the bath in blue there original holes coming out of the wall

fitting 2 offset soil elbows at the side of the extension wall will bring the soil pipe external and therefore you can run it up the side of the house

View attachment 501859

at a guess this is how your pipes run purple is the gully to the main drain this gully pipe can be moved down the side of the house and a new soil pipe up the side of the house

whilst fitting a tee you can then rod it but you wont need to do

View attachment 501860

I see your thinking, but a) yes, that's my garage and b) it's just more pipes to encase under the foundations as the new downstairs W/C has to go somewhere. It's all been thought out, I'm just figuring these last things out. Nothing is changing!

 

[gaz1]

to be honest id go to the left side easy to box in

run the new soil into the new toilet from where it is or dig and fit new drain once there you only need an air breather within the toilet whilst id rather run the waste from the sink and connect it outside

whilst your doing your extension i presume your doing away internally ive already done it

 

[Jaeger_S2k]

In a bathroom or a WC, it's a basin.

In a kitchen, it's a sink.

The plumbing is being planned for an upstairs bathroom, it's a BASIN and a downstairs WC, it's a BASIN.

 

[Jaeger_S2k]

What's this about an 'Elephant's foot' though?

Oh, it's just a nickname for an AAV (Air Admittance Valve) at 100 mm if you turn it upside down, it looks like an “Elephant's Foot”