moving sewer for extention advise

D

Davidandkeiley

Joined
18 Sep 2019
Messages
44
Reaction score
1
Country
United Kingdom
Hi all I'm after a little bit of advice. I am looking into the idea of having a extension to the rear our semi detached property. We currently have a conservatory [already built when we bought house] and we would like to get rid of this and build a 3m x 3m extension in its place. We would then knock through to create a kitchen dinner. The problem is that there is currently a manhole/sewer in the middle of the conservatory that serves us and the neighbours. The manhole has got a cover on that is bolted down and has been fully tiled so at the moment I am unable to lift it without causing a lot of damage to the floor. I've spoken to next door and he said that his drain is about 6ft deep and have a pipe feeding in from one side then out via the other side and it also has our connection [basic drawing below]. All neighbours have a manhole in their gardens. We will be getting some builders in over the next few weeks to have a look but would like a basic idea of what work would need to be done with the drains to see if it is a viable option or not.
many thanks
Dave

upload_2019-9-18_19-41-57.png
 
Sponsored Links
Unless your water company permits internal manholes, you're stumped.

I'd be sceptical about any builder's opinion.
 
6' is very deep. All your new foundations will have to be a little deeper and any alterations to the existing sewer will require WA approval and it will be difficult work.

The obvious solution would be to re-hash the drain so that the IC lands outside of the proposed extension footprint and down-stream (in the 'patio' area). It will be a difficult messy job with a permanent risk of collapse and the need for mechanical digger access. Expensive too.
 
Last edited:
Sponsored Links
Thanks for the replys as soon as he said how deep the manhole was i thought it would be a no go. Hopefully will be able to get mine up today to check. The searches we had back from southwest water show no public drains in the rear gardens however i guess they are wrong.
Dave
 
I've managed to get the cover up in the conservatory and the manhole is in the picture added. It's actually about 4.5ft deep does that make any difference or is it still going to be a nightmare.
Many thanks
Dave
 

Attachments

  • 20190919_125232.jpg
    20190919_125232.jpg
    238.9 KB · Views: 311
Its not necessarily a showstopper, but it could cost a few £k......and there may be no solution acceptable to the water company.

If you really want the extension, maybe the cost would be worrh it.
 
We had a similar problem when we built our extension. We didn't want any manholes inside, so our solution was to send the sewage pipes out away from the house and into a sump pump at the end of the garden. This allowed for the loss in fall of the pipes. The pipework from the pump then kicks back and joins into the original sewage pipework.
Cost a few ££ to do, but worth it. Just means we have an electric box in the utility with an alarm if anything ever went wrong and a cover in the garden for access to the pump.
 
Being my local waterboard, SWW will not allow an internal manhole, they will expect it to be relocated on the system somewhere within your plot if you wish to pursue it. So the extension will need to be designed to accommodate a new manhole on the system somewhere beyond the extension perimeter, falls and bends permitting.

At the time of writing they will charge you about £180 for the Build Over agreement (for which you will need to provide a CCTV survey at about £160), £247+VAT for the manhole removal and another £247+VAT for making a new connection/new manhole though if you can coordinate it so they only need to inspect both new bits on a single inspection then you should get away with just the one £247+VAT fee. The builder or whoever will be doing the drain works will need to demonstrate they are competent and provide method statements and risk assessments and fill in some crappy forms for each element of the works.

You’ll also need to apply for a Full Plans Building Regulations Approval (as opposed to doing it on a Notice) and include some plans showing the existing and new drain runs, their inverts and some drain sections demonstrating the depth of the new foundations in relation to the drain which will all need to be sent off SWW when you apply for the Build-Over.

You’ll need all these approvals in place before works can go beyond the drains.
 
Thanks for all your replys its much appreciated. I've got sww development department calling me back tomorrow so i can discuss it with them. I've looked at both the neighbors manholes and they are about 6m either side of mine and run in a straight line so depending on cost we will try and go ahead if we can justify the cost. It's that or move house . We would look to locate it on the patio as extension will be on the same foot print as the conservatory
 
Davidandkeiley said:
Thanks for all your replys its much appreciated. I've got sww development department calling me back tomorrow so i can discuss it with them. I've looked at both the neighbors manholes and they are about 6m either side of mine and run in a straight line so depending on cost we will try and go ahead if we can justify the cost. It's that or move house . We would look to locate it on the patio as extension will be on the same foot print as the conservatory
Click to expand...

A job I did in Surrey cost about £3k -to move a 110mm public drain. That needed the public drain moved by a couple of metres and a new brick build manhole formed. All the pipework had to be clay not plastic (they insisted on replacing like for like). Obviously that price doesnt relate to your project, but maybe it gives you an indication of scale of cost.

Thames water sent their own CCTV team to do a before and after check.
 
Sorry if this sounds stupid but who would it be best to use on drain projects? Is it ground work company's or civil engineering type company's
 
noseall said:
Hello Freddie. How was HMP?
Click to expand...
Comfortable, apparently.
He did not want to break free. :cautious:

I took this picture in August when I was walking the spaniels on Dartmoor. I felt compelled to knock the door and ask how this got through planning in an AONB, and the governor said the bloke on the top floor assured him it was PD. I said you better check that mate, as the advice seems a bit dodgy.
foto_no_exif (13).jpg
 
D

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
You must log in or register to reply here.
Sponsored Links

Similar threads

S
Moving Sewer Inspection Covers
Replies
7
Views
3K
andemz
A
S
manhole advice
Replies
6
Views
2K
stevie12345
S
W
build over foul sewer
Replies
4
Views
2K
^woody^
^woody^
J
Drainage plan for extension
Replies
10
Views
1K
^woody^
^woody^
W
Building/Extending Conservatory - Sewer Problem
Replies
2
Views
1K
wingcoder
W
Back
Top