Running new foul sewer into existing 1930's manhole

[frank999]

I will be wanting to add a new inlet (from a ground floor extension) to an existing 1930's rigid Pipe foul drain system, which from what I can judge From Thames Waters guidance literature - is a 'Private' sewer

I perceive allowing inward connections to an access chamber at the side of the property - currently there is the existing concrete chamber there - with half rigid pipes running through and out of the chamber.

Reading Building Regs document H, 2.53 - guidance is given on how branches entering should be run:
https://assets.publishing.service.g...achment_data/file/442889/BR_PDF_AD_H_2015.pdf

Is it feasible to add new inlets to the existing or would you replace the manhole altogether, it has been suggested that replacement may create more issues than its worth - then again a blocked drain at 11pm is also an issue.

Any thoughts appreciated.

 

[Ian H]

I’d replace it if it wasn’t too deep or add on if it was deep.

 

[^woody^]

Bang a new pipe through it

 

[frank999]

Umm my inclination is to keep it ... will want to make any drop or incline into the current flow as smooth as possible - or it'll make for a rank inspection chamber, will read Document H again.

 

[noseall]

We often hoof out and replace with plastic. Much better long term.

 

[frank999]

Umm - I know that with new, the bob sleigh ride would be much smoother for the descending (or assailing) detritus (and so less chance of blockages), I've noticed the poor condition of the interior of some chambers, crumbling concrete and walls - so guess that would be sorted in one foul swoop.

These days with idiots putting 'flushable' wet wipes down the dunny, a smooth a path as possible needs to be provided ...

Umm, maybe new then ... its a private sewer, from my understanding ... do I need to inform The Local water Board (Thames Water) ? ... I understand that we do not ...

 

[Ian H]

No you don’t have to tell them.

 

[John D v2.0]

Thames water won't be interested unless it's on someone else's land or someone else's waste flows through it. Technically you would have to get building control to check the new work, as it wouldn't be classed as maintenance to add the new pipe, but if you're doing the work yourself and are confident then you may not decide it's the best use of money.

 

[Hugh Jaleak]

If it only carries waste from your property, it's private. If anyone else connects at that point or upstream, it's shared, so is Thames responsibility. You dont mention depth, be aware the 450mm plastic chambers are not suitable for deeper manholes.

You say it's concrete and in poor condition? That is ringing alarm bells for me, Hydrogen Sulphide, (a highly toxic sewer gas), attacks concrete and metal, if the existing chamber is in poor condition, I would be concerned about the presence of H2S. Firstly due to the apparent damage, and secondly for you or anyone else unaware entering the chamber or any excavation to replace the chamber, without adequate precautions. 2 men died in the USA only last week after being overcome by sewer gases.

 

[Nige F]

Pictures of it's layout/condition would be useful