New soil pipe into existing sewer system

[Another Steve]

Hi,


I would very much appreciate you input on my project.


Project: I am building a side extension which incorporates a new WC. My build will go over existing sewer pipes and manholes.

Status: I have planning council permission and now I wish to obtain Thames Water Build Over permission. Following this, I will have building regulations drawings created and submitted.

Aware or excluded: I am aware of what I will need to do for foundations and for ease I have excluded Surface water drainage. I am also aware that I may need to create rodding access where manholes are removed.

Questions: My new additional soil pipe will be at the Green Circle. What is the best way to plumb this new pipe into the existing sewer system? Also, what rodding access do I need to create and where?


Thanks again

 

[Ian H]

You could run it to a new connection in the manhole at the front if you came down parallel.

If it we me I'd be happy with a Y junction onto the shared section but the rules and regulations may say otherwise. That's if it's not stupidly deep and assuming the Y is fitted properly.

 

[Another Steve]

I was thinking they were the two options (FYI the sewers are not too deep, invert level approx 1 meter):

The Y fitting would clearly be easiest and I suppose I could have a rodding point off the soil pipe (To rod down the Y fitting if needed). I can't find anything either permitting of forbidding this Y fitting option. Although a couple of non-experts I know have the opinion the new drainage needs to go to a chamber/manhole. (See Regs H excerpt attach)

I still wonder if I need rodding points (pipes and access holes) for the 90 degree bend at the decommissioned manholes.

REGS H EXCERPT

 

[Ian H]

You might have to have rodding eyes but only because the rules say so. Probably outside at the back so you can come straight down and past where the manhole used to be.

If you put a Y on to connect your toilet I could pull my jetter up the junction in the unlikely event the new drain ever blocked. I could also unblock a blockage in the 90's that will replace the manholes. I'd rod from the new manhole at the rear first, if that didn't clear it I'd jet from the manhole at the front.

 

[Ian H]

Looking at the regs you posted I'd say 90's in place of the manholes and a Y junction for the toilet would satisfy them.

Just make sure whoever does it makes sure the joints are perfectly aligned and watertight.

 

[Another Steve]

Thanks Ian, that makes a lot of sense and definitely practical.
I know that I can discuss this with my Building Regs Inspectors when I get to that stage and possibly amend plans (they are actually quite helpful where I live).
However, I need to get through the Thames Water Build over agreement first... They were not the most helpful on my last project...

 

[Ian H]

Good luck with the project