PUBLIC SEWER CLASS III RE-ROUTING.

Hi all, we are planning an extension for which we have already submitted plans but have just had a letter from thames water telling us we have a class 3 public sewer running under where the extension will sit.
A class 3 public sewer is fairly heavy duty and 492mm diameter was mentioned by the architect, as well as this there is a manhole which will need to be re-sited.
At the moment the sewer runs straight along the back of the houses and what we will need is to interupt the straight flow to site our manhole outside (roughly 9ft out).
Hope this makes sence, my concern is thames water will want to do the work as its a fairly major sewer and they want £1300.00 to do an inspection/survey!
Has anyone got any helpfull advice or had to do similair?

Are Thames water insisting on a re route?
I have seen them allow a build over a sewer with foundations re configured to protect the drain and an access chamber either side of the new build.
One thing is for certain this process will drain you of money!
Good luck
Pete

BREAKALEG said:

A class 3 public sewer is fairly heavy duty and 492mm diameter was mentioned by the architect

Click to expand...

492mm.

How deep?

Your right a class 3 is serious stuff and the survey is at your cost , in my experience our water company (anglian) very rarely grant an agreement for a class 3, as said before how deep is it ?

The pipe is appx 2 meters deep and is a class 3 trunk sewer which can not be re-routed, the reason for re-routing was that the man hole is directly above the sewer and currently where our proposed extension will sit and i'm told since 1997 manholes cannot be within a building or built over.

On a plus note the lady from thames water said our footings should be allowed as they are 1.5 metes away from the sewer although they will need to be dug deeper than the sewer!!
Also we have an outbuilding with supended timber floor built over the manhole presently and this part of the build was only going to be partially re-built and fully renovated/insulated etc so we have a arguement for leaving the manhole within this part of the building

On the down side i'm looking at a bill just under 2k (at least) to thames water plus the extra foundation works.