Bathroom and soil pipe.

[Screech20]

Hey guys.

I'm soon to start the bathroom project and want to move the soil pipe around.

I will be getting building control involved as we've got walls to move etc but want to have in my head what i plan to do is doable or whether i need to re-think before everyone else in involved.

I've (hopefully) attached a sketch which hopefully explains what i plan.


Basically it will go to an AAV in the loft for now, then eventually it will be connected when we do a loft conversion. (This is a bungalow)

On the existing sketch, the vent pipe is a guess, as it comes out of the ground before the man hole, but not really sure how it's connected - i'm just guessing inline.

I'll need to get the bath waste into it somehow, i'm thinking of a manifold at the toilet junction?
It currently goes out to a gully, which is being done away with (hopefully)




Any advice would be appreciated.

Cheers

 

[theprinceofdarkness]

Its probabley an over sight, but your toilet has to drain uphill to the manhole in the second sketch. I would tend to go with a staright pipe from manhole to the bend near the kitchen waste, with the toilet T'd into it. This would give you a nice rodding length, with just the end 12" in the T under the toilet a bit difficult. See what the experts say!
Frank

 

[Screech20]

Sorry, yes that's not very clear, the bit between the toilet and the manhole would remain untouched apart from the existing vent to be cut and capped at ground level in some way.
That's meant to look like it going away from you as you look at it, not uphill

Cheers

 

[Nige F]

Hey guys.


On the existing sketch, the vent pipe is a guess, as it comes out of the ground before the man hole, but not really sure how it's connected - i'm just guessing inline.

I



Any advice would be appreciated.

Cheers

I'll bet the existing vent goes into the manhole @ high level

 

[Screech20]

I wondered that too, but it doesn't.


Cheers.

 

[Screech20]

Here's a photo from outside...

 

[tomfe]

You've not given enough information, are you digging up the floors?
The best option would be to run a new pipe from the old soil under the floor and not try and connect to the existing toilet, you'd end up with 3 90degree bends in the system instead of 1.
So if you run water down the stack outside does it not flow into the mane hole, I'd keep this for now, you can always cut it sorter and add an external air admittance valve.

 

[Nige F]

I think your drawing is correct - the vent is Teed off the top of the pipe to the WC. I don't think Build control would like the new pipe running horizontal and then down into the old WC outlet. Are your floors wood? if so you could run under the floor. (If you're in E.sx I can give you a name of a good guy for the loft conversion when the time comes. )

 

[Screech20]

I was hoping to not dig any floors up, but if I need to then I will.
If you look at the photo, top left hand corner where the gas pipe enters, is where I want/need the new soil pipe to run (inside)
I could run it down and out, and pick up the pipe that is currently the gulley. That just means I'll need to dig outside and inside, and get it through the cavity wall.

I think I could then cut the old stack away but keep the toilet going the same route without the vent as its within 1.3m from the drain..?

Cheers

 

[Screech20]

Yes I do have wood floors with a little void, but then I think the T would be within 450mm of the bend to the drain. I'll have to have a measure up!

 

[Screech20]

Are your floors wood? if so you could run under the floor.

So with this in mind, just done this quick drawing, which would run under the floor (200mm void) then tee into where in currently comes up from outside. As long as i've got the magic 450mm?
Tbh this is pretty much what i had in mind except would have been above the floor. So i'm thinking i've completely misunderstood



Thanks for the advice, it is appreciated!

 

[Hugh Jaleak]

I'd go with removing the gulley, and connecting the new stack to that. I don't think Building Control will be too impressed with the layout in your last sketch, bends are best avoided in the wet section of a stack, and you will struggle to get access to clean it out should the need ever arise. You either need to run at current invert level under the floor, then come up with a long radius bend, but then the existing drain appears to be running in the wrong direction as your drawing shows it turning 90° before coming horizontally, or take the stack up from the existing drain and connect the new bathroom to it at first floor level.

Leave the existing WC as is, and just plug the current vent with an AAV. You're quoting distances, not quite sure in what context, but for guidance the Regs say a ground floor WC can be directly connected to the drain provided the distance between the crown of the WC trap and the invert of the drain is no greater than 1.3m. Secondly, no connection is permissible into a stack within 450mm of the invert of the drain.

 

[Screech20]

Tbh I had a feeling that would be the best option, I was just hoping for an easier route if it was allowed. But If I've got to do some digging, then so be it if it means a proper job!

This means I'm going to need to dig down both inside and out to get a long radius bend in, am I right I'm thinking I need to lintel both inner and outer walls?

I also think I'm going to need an inspection chamber because I'll need to change direction as soon as it gets outside, as the gulley is right against the wall.
Although looking at the photo, it must currently have a 90° between the drain and gulley.

The distances I quoted were for the current WC connection, as I'm guessing it's already over 450mm, but it's also within 1.3m so it can actually enter directly as it is without the vent pipe?


Cheers

 

[Hugh Jaleak]

Yes, you will need to support the weight of the walls above where the pipe(s) pass through with lintels. Depending on depth, you may get away with a shallow (225mm diameter) inspection chamber immediately outside, but I'd dig down and expose the existing pipework from the gulley before getting too excited, it could be heading off in any direction.

I'm confused about the distances still though. Not sure what you're asking? The WC can be directly connected to the drain, (i.e. you don't need a stub stack and/or AAV), provided the drain is <1.3m deep. The 450mm is used on stacks taking waste from upper floors, no connection may be made within 450mm from the invert (bottommost point) of the drain. If you're keeping ground floor WC on a separate drain then there shouldn't be an issue.

 

[Screech20]

So things took a bit of a back step yet again but today I finally managed to get a bit of the drive dug up to find where the pipe goes.
I actually pumped through it at one point as it is just below the concrete!
Pics below.
As you can see I've taken it right back to the man hole and figured out the new route.





The vertical white mark is where it needs to go, the horizontal is the floorboard level. Ideally I need at least 450mm to that point, which I think will just about make.
The hose is the last pic shows the straight line that I can take. I could make a joint, but as I've gone all the way, should I just renew to the man hole? (How?)
Cheers