New toilet connection to underground.

[NickH]

The poor standard of workmanship in new builds is hardly relevant to the preferred layout of a drain.
If there are existing stacks with vents, which presumably there are as this is not going to be the only bathroom, then for a ground floor WC so close to a manhole you just wouldn't have an external stack.

 

[Gilesda]

Thanks for all the replies they are much appreciated.
I'll try and load some pics later but I'm not sure they will help.
The utility and this room are an extension of the main house which is a late sixties build. The extension was built in the early eighties I believe.
It's flat roofed and very cold with little or no insulation in it. I've improved that in the utility room with a Celotex hybrid roof and Celotex on the walls and floor.
I'm doing the same in this so called bathroom and as I'm now about to batten the floor and insulate it I thought I should give a bit of thought to the plumbing.

The room has one outside wall where I was going to position the toilet. I planned to core drill through this wall and drop straight down underground. The sewer pipe runs along this wall with a manhole at each end. The front manhole has an interceptor (that occasionally blocks at its exit hole) before the sewerage goes off to a neighbour's property which has a main drain on it.

The manholes are about 700mm deep which is how far I have to dig down to connect to the pipe. I was going to cut a section of this out and put in a plastic swept Tee. The existing pipe is glazed clay which I hope will cut with a Stihl type saw. I've got an inflatable balloon type of thing to block the flow at one of the manholes while I do the cutting and connecting.
What I didn't know was having to tell the water company about this work. The house is a semi and next doors sewerage passes through my drains. There are no other houses connected to it.

I hadn't thought about the extensions foundations either. Going straight down the wall I'm likely going to hit them.
The shower outlet will be 2m from the outside wall. I was planning to raise this up on a plinth kit. I'd rather not go through the floor with any of this.

I kind of visualised it like the picture below though I don't know what an air admittance valve is or where to fit it.

"A stub stack would be typically found where an additional downstairs WC has been installed and it is often easier to bring the pipe work through the external wall then excavate the floor inside the property, it is always prudent to install some kind of access point on a stack and the one shown allows access into the drainage system and also direct access to the back of the pan should a blockage ever occur.

The image shows a sub stack that serves a toilet only, if a waste pipe from a hand basin was connected to the pipe work an air admittance valve would be required inside the property. "

 

[Rob Foster]

Thanks for all the replies they are much appreciated.
I'll try and load some pics later but I'm not sure they will help.
The utility and this room are an extension of the main house which is a late sixties build. The extension was built in the early eighties I believe.
It's flat roofed and very cold with little or no insulation in it. I've improved that in the utility room with a Celotex hybrid roof and Celotex on the walls and floor.
I'm doing the same in this so called bathroom and as I'm now about to batten the floor and insulate it I thought I should give a bit of thought to the plumbing.

The room has one outside wall where I was going to position the toilet. I planned to core drill through this wall and drop straight down underground. The sewer pipe runs along this wall with a manhole at each end. The front manhole has an interceptor (that occasionally blocks at its exit hole) before the sewerage goes off to a neighbour's property which has a main drain on it.

The manholes are about 700mm deep which is how far I have to dig down to connect to the pipe. I was going to cut a section of this out and put in a plastic swept Tee. The existing pipe is glazed clay which I hope will cut with a Stihl type saw. I've got an inflatable balloon type of thing to block the flow at one of the manholes while I do the cutting and connecting.
What I didn't know was having to tell the water company about this work. The house is a semi and next doors sewerage passes through my drains. There are no other houses connected to it.

I hadn't thought about the extensions foundations either. Going straight down the wall I'm likely going to hit them.
The shower outlet will be 2m from the outside wall. I was planning to raise this up on a plinth kit. I'd rather not go through the floor with any of this.

I kind of visualised it like the picture below though I don't know what an air admittance valve is or where to fit it.

"A stub stack would be typically found where an additional downstairs WC has been installed and it is often easier to bring the pipe work through the external wall then excavate the floor inside the property, it is always prudent to install some kind of access point on a stack and the one shown allows access into the drainage system and also direct access to the back of the pan should a blockage ever occur.

The image shows a sub stack that serves a toilet only, if a waste pipe from a hand basin was connected to the pipe work an air admittance valve would be required inside the property. "

I really would get building control involved there are a whole load of issues here
centralheatking

 

[Gilesda]

I've done 2 jobs in the past with building control involved. I had no problems but I'd rather not involve them here. I'm putting plenty of insulation in the room but the amount they ask for these days would affect ceiling heights etc. I figured it's already classed as a bathroom so I'm just improving an existing.

 

[Rob Foster]

I've done 2 jobs in the past with building control involved. I had no problems but I'd rather not involve them here. I'm putting plenty of insulation in the room but the amount they ask for these days would affect ceiling heights etc. I figured it's already classed as a bathroom so I'm just improving an existing.

Parts of this might be planning permission, or change or establishment of use, but certainly what you plan would come under building regs, which might make your property un saleabke or un insurabkle ...just friendly advice centralheatking

 

[Gilesda]

Parts of this might be planning permission, or change or establishment of use, but certainly what you plan would come under building regs, which might make your property un saleabke or un insurabkle ...just friendly advice centralheatking

That's fair enough Rob Foster, I appreciate it's friendly advice.
I'm starting to have second thoughts about doing this now. I was talking to a neighbour earlier today who has just finished building an extension on the side of his house similar to mine but bigger. He paid the water authority £800 and with building regs approval paid £2500 before he laid so much as a brick.
He's done a lot more than what I was going to do though. He removed a manhole, his front interceptor and laid a new sewerage pipe that runs under his extension. That gave him a downstairs toilet and a extension to his kitchen. Plus he got rid of his interceptor that has also like mine blocked up in the past.
Anyway I'm not sure what to do now so I'll say thanks for everybody's help

 

[Gasinspect]

Builder I work with sometimes, doesn't use the Local Authority Building control, but uses an independent Approved Inspector, much more approachable and reasonable, both in approach to issues, and cost. They tend to be very experienced and knowledgeable from what I have seen.