Drainage plan for new extension

[Davidandkeiley]

Hi all I'm after a bit of advice with regards to our proposed new extension. We have had planing permission and building regs sign off for a single story extension. I've also had approval from southwest water with regards to removing the manhole that is 1.6m deep and approx 1m wide and moving it out of the footprint. Southwest water have said i can remove manhole and make redundant. I'm about to start getting quotes for the ground works but would like to know what the job involves. I understand the existing channels need to be replaced with round pipe. However what i am unsure about is will the concrete rings that make up existing manhole need to be removed or can these can be left in place?
I've contacted southwest water but had no reply at the moment
Many thanks
Dave

 

[Hugh Jaleak]

Going to need to get 2 decent stubs of pipework to connect onto, to bridge the gap currently formed by the manhole. I cant see you breaking the benching out without fracturing the pipe, so would expect you'll need to remove the manhole and a good chunk of the concrete base, in order to be able to get to cut into the existing drain.

 

[Davidandkeiley]

Thanks for that Hugh. I've had 2 different people around today to price. 1st one said he would do it all without removing the concrete ring as it would take to long and as it would be a live drain would not be easy and would be cheaper.The 2nd person said to do it properly he would remove it all and replace pipe as you have said then build a new manhole outside the footprint. Will cost more but its done properly

 

[frutbunn]

I always insist these be removed and new pipework installed, though I have heard some BCO's allow it to be left in place and a plate put over the top, but to be fair this was a builder telling me this when he didn't want to break out a similar manhole I was insisting had to be removed!