Waste Pipes under B&B Foundation without Manhole

[Patrick]

Building Control had a look into our Sewer connection plan(see below) and send  me some technical guidance for Y-connections under buildings:

 

 

 

 

 

The informal advise from some of the Wessex Water guys that came to my site was

:" just plug it back into the old system where it was connected before , and it ll be alright"

To explain>

there has been a building before in place and this has been connected to the sewer line running underneath it . So I just thought to connect it back into this exisitng connection again.

This obviously potentially brings problems with blocked pipes. The way to avoid this would be to have a Access chamber and a rodding access to each side of the building, which in my case is not possible as the main sewer runs UNDERNEATH the building (I have permission to build over sewer by water supplier in case someone asks)

So  the  method I see to follow the above Guidelines, is to not connect via the existing connection underneath the house but to connect via new Access chamber outside , roughly like this:

 

 

 

 

 

 

 

 

 

 

Or is there an option to save the trouble and still connect to the sewer via the existing connection (underneath the house) , maybe with a rodding access in the house or just outside the house .

 

Would prefer this, but obviously dont want to create problems later on ( under slab plumbing always seems a bit risky)

 

 

 

 

 

[Russell griffiths]

I prefer your second option. 

Hate the first version. ??

[Nickfromwales]

You wouldn’t have a 110mm branch just to pick up a WHB anyway so a bit OTT at first glance?

[Patrick]

35 minutes ago, Nickfromwales said:

You wouldn’t have a 110mm branch just to pick up a WHB anyway so a bit OTT at first glance?

OK. This wasn t right, I see. But the principle of having plumbing underneath the Foundation with the connection to the main sewer  being under the Foundation as well is completely unacceptable? Or just uncommon and doable?

[Russell griffiths]

Common sense should tell you not having any outside rodding access is not sensible. ???????

[Declan52]

35 minutes ago, Patrick said:

OK. This wasn t right, I see. But the principle of having plumbing underneath the Foundation with the connection to the main sewer  being under the Foundation as well is completely unacceptable? Or just uncommon and doable?

Put it like this if a brown trout gets stuck on its merry way down your pipe then how are you going to ensure its removal without a rodding point. 

[Patrick]

I understood your shit exploding hint. @Russell griffiths

@Declan52

I understand the issue. But question remains. Can I have the pipes underneath the Foundation. If the solution is to put ab access /rodding point to the other side of the house and extend pipework to there, then this might be a decent option. Better than installing a full manhole. Or do I still not get this right?

[Russell griffiths]

As long as you can rod unblock you can put it wherever you want, there are no hard and fast rules, you need to demonstrate a method that works. With your long house wouldn’t having rodding eyes at the far end be a long way to go, surely your second drawing is fairly simple. 

[Russell griffiths]

Looking at your drawing, depending on depths could you not have a manhole in the exact location in the first drawing but outside the building line, so your new pipes run shallow over the top of the sewer, then outside to a manhole, this then drops down into the sewer. 

[Patrick]

Nope. The sewer is around 40-50cm from the watercourse, so can't put a manhole outside the building. Will have to do something similar to drawing 2.

[Patrick]

On 24/09/2019 at 21:51, Russell griffiths said:

Looking at your drawing, depending on depths could you not have a manhole in the exact location in the first drawing but outside the building line, so your new pipes run shallow over the top of the sewer, then outside to a manhole, this then drops down into the sewer. 

Ok, my fault, you where right @Russell griffiths . Had a second look at it and will do as you re telling me ?. Thought that space will be too narrow between foundations and stream , but seems I can squeeze a Inspection chamber in there. And that will be a much better solution I guess .

 

It would look like this :

 

 

 

only problem there is the 90degrees bend into the IC , i think.

Is this possible/advisable ?

 

I could add a Rodding access on the other side of the building  if that makes it better, like that:

 

 

[PeterW]

25 minutes ago, Patrick said:

only problem there is the 90degrees bend into the IC , i think.

Is this possible/advisable ?

90 degrees into an IC is standard - all the side entries are either 90’or 45 to the main channel flow.