Extension Advice

[Academic]

Afternoon all,

I want to build a two-storey extension on the back of my house. It was set to be 3m x 7m but there happens to be a waste water sewer pipe and manhole access cover running exactly 3m from the back of my house

So the choices are, I can come back towards the house 0.5m to avoid it but that would defeat the purpose of the extension - not worth the cost for the reduced room size

I could pay to have the water board move the pipe - any ideas what this will cost?

Or, I was wondering if I could build over the pipe and manhole with the access point being inside the new building. Is this possible?

Any advice welcomed. Cheers.
_________________________________
lynda, moderator

please note forum rule 9

 

[^woody^]

If it is a public sewer, then the water authority will have to agree your proposals, and most likley would want access chamber outside the buidling. Building within 3m of a sewer will require their permission, as well as building control approval

Otherwise your options are to divert the pipe, or you could have an internal chamber.

 

[Static]

I could pay to have the water board move the pipe - any ideas what this will cost?

Cost.. lots.. probably last restort

Or, I was wondering if I could build over the pipe and manhole with the access point being inside the new building. Is this possible?

Need to change the manhole to a screw down type and make sure its accessable internally if needs be

 

[noseall]

does the sewer pipe, drain any other properties other than your own?

if so, the chances are, you and your neighbours co-own the sewer, unless your property was built prior to 1937.

if not, it is solely your responsibility, and therefore yours to do as you wish. as woody says, the best solution would be to re-route the drain to the outside perimeter of the building.

 

[diyisfree]

I built an extension to the side of my house. I live in a late 40's built semi on a hill.

I am the end house at the bottom of the hill and the next 2 semis up from me drain all their sewerage in to my manhole. I simply pre dug a new manhole and construction all necessary inlets and outlets and tapped into the main sewer.

Once all that was done I informed my neighbours to cross their legs for a couple of hours while i diverted there flow into the new manhole.

BC came up once completed, looked said fine carry on and backfill He had one concern and made me fit a rodding eye but apart from that all was done in a couple of days.

 

[NS215]

i had the same problem with an extension on my property that i've just completed,
the company wrote to BC saying it was a public sewer
(house only built in the 60's)
so BC wrote back to them and asked for permission to concrete over (obviously bridging pipework), BC told me they had 28 working days to reply or if no reply you can carry on regardless as you can presume there happy with your proposal, so left 6 weeks and no reply so carried on

 

[^woody^]

I thought it was unlawful to build over a public sewer without the water authorities permission?

And they could insist on you removing any work not approved by them, which could potentialy affect the sewer.

The LA's around me will not give permission to carry on work, untill the water company has approved the design - and this includes the water company insisting on the homeowner providing a CCTV survey at their own expense and paying a fee to them for checking the plans

 

[jeds]

Woody is right. Building over or diverting a public sewer of your own accord is simple in terms of the work involved but you leave yourself exposed to several potentially serious problems going forward.

Firstly the sewerage company could remove your extension and charge you the costs for doing so. They won't hesitate to do this if they need access to the sewer for any reason. Secondly you will most likely be blamed for any problems occuring with that sewer in the future. If that involves flooding of a neighbouring property - or your own property come to that - those sort of costs can run into many thousands. Thirdly you may have some difficulty selling the house if the buildover/diversion is not properly documented.

 

[Academic]

I've been in contact with the water board and apparently it's a private sewer. The house is the end terrace in a row of 3 and the sewer serves the 2 houses above me as well as a couple down the road before it joins the public line. Therefore apparently (on reciept of confirmation), I can build over the existing pipe as long as I dig foundations deeper than the pipe and lintel over it so that the pipe has no load on top of it. The manhole access would then be just inside my new building, fitted with a double lined manhole cover. Does this sound right? The access from inside wont be a problem, it's going to be right next to french doors so will have nothing on top of it apart from floor covering.

I'm not sure how a lintel would be placed over the pipe though. Any ideas on this? Does it involve an extra layer of blocks from the base of the foundations to a height just above the pipe?

 

[NS215]

Woody is right. Building over or diverting a public sewer of your own accord is simple in terms of the work involved but you leave yourself exposed to several potentially serious problems going forward.

Firstly the sewerage company could remove your extension and charge you the costs for doing so. They won't hesitate to do this if they need access to the sewer for any reason. Secondly you will most likely be blamed for any problems occuring with that sewer in the future. If that involves flooding of a neighbouring property - or your own property come to that - those sort of costs can run into many thousands. Thirdly you may have some difficulty selling the house if the buildover/diversion is not properly documented.

not off my own accord a letter was sent to the LA and no reply was given so was informed by BC that i can carry on as LA have 28 days to respond and no response was given
i'm quite lucky also that i live at the bottom of a hill and my house is first on the run so any problems would only inconvenience myself and i could carry out any repair myself

yes build the blockwork footing leaving a 6inch gap around the sewer then lintel over the pipe onto the blockwork either side of the pipe

 

[mk85]

I'm going to have a similar problem when i start my extension. The manhole is within the extension area. Is there a way to find out if my neighbours waste drains through my manhole on a website or something or will i have to contact the water board? Its a terraced house, 3rd one from the end. Its in london and was was built in 1894.

 

[jeds]

What you really need to know is if it's a public sewer or a private drain? The water board will be able to tell you this. If it is public, this is the thing that may hold up your works. It is therefore best to establish this early on and negotiate any buildover detail with the water board before you get too far down the line.

If it is private the water board will most likely not have any records.

 

[noseall]

What you really need to know is if it's a public sewer or a private drain? .

read the post by Academic wrote about 3 above yours.

 

[jeds]

My post was in response to mk85.

 

[noseall]

My post was in response to mk85.

doh.