Help/Advice for small rear extension (drain issues). inc pics...

[pb2012]

Hi all,

I'm looking to buy a new property and it hinges, to a fair degree, on the ability to create a little more living space.

I've attached 4 images to this post.

basement-floorplan-options.jpg:

What I'd like to achieve. option is 1) is a fallback, Option 2) is preferred, and option 3) would be no extension at all (not so much of an option!).

back1.jpg:

Full view of the rear.

back2.jpg:

Isolation of manhole/drain cover.

back3.jpg:

Illustration of planned extension in relation to pipes etc.

My questions are:

1) How much of an issue would you think that the manhole is? I'm happy to not move or build over it, but I need to at least go right up to it. I'm hoping no unexpected extraneous work would be needed with this.

2) Can you see any issues with re-routing the central drain pipe, and current internal sink pipe? Can I just run these off in to a relocated drain further down the garden?

3) Could the manhole to the left be used when re-configuring the current drain pipes?

4) are there any other issues I should be aware of that would kill or limit the extension plan?


If anything is likely to create a lot of complicated work and extra cost that would be an issue.

Thanks in advance for any help!

 

[^woody^]

It's all probably. Don't buy a house based on some random forum opinion - even if its quite good opinion.

Get it surveyed and instruct the surveyor to comment on the viability of whatever you want to do with the place.

 

[pb2012]

It's all probably. Don't buy a house based on some random forum opinion - even if its quite good opinion.

Get it surveyed and instruct the surveyor to comment on the viability of whatever you want to do with the place.

Fair enough. I think if it turned out that an extension was simply impossible for any reason I'd still go for it. It would just be a bit less ideal.

I think that forum opinion and comment is still valid. Perhaps I can get some ideas I'd not thought about, and be better informed when it comes to having conversations with builders and planners.

 

[Notch7]

rainwater downpipe is no issue.

Kitchen gully no problem

Manhole -problem!
if its a sewer run joining other properties -very common on terraced houses, you will need a build over agreement from your local water authority (which is not guaranteed). Build over should really be called build near to -as agreements are required if you build within 3 metres (from memory). If you build to miss the manhole, you prob need to be 500mm away.

foundations need to be 150mm below invert level -so you need to know how deep the pipe is.

You will be building within 3 metres of the neighbours foundation so may need a party wall notice.

Hopefully you dont have bats, newts, roman remains, knotweed, TPO trees or anything else requiring an expensive report

 

[pb2012]

rainwater downpipe is no issue.

Kitchen gully no problem

Manhole -problem!

Yea, damn that manhole! I think a 500mm clearance would just about be an issue. I'd ideally like to build just beyond the back door which would be pushing it.

I suppose I need to get the cover up and see what's going on under there.

If it is of any consequence, the main sewers and their access seem to run at the front of the property. There are lots of standard manholes along the pavement and in the middle of the road.

I have a suspicion there is a sewer run under that back-garden cover and this house is at the end of it, then leading under the property to the main sewer.

 

[^woody^]

Of that age, all the drains are likely to be public sewers (maybe combined?) so you are in the hands of the water authority as to what they will allow.

If there are other similar extensions then its possible you could have one too.

Otherwise you are into a load of guesswork on here about what may and may not be possible. Looking at it, its a straightforward extension with the usual technical solutions. But what they may be and at what cost you wont get here.

 

[Ian H]

If the drain starts at your kitchen gully then goes left into the neighbours it would be much easier. You need to lift the lid.

 

[pb2012]

I have a bit of an update on this.

I got a sewer map for the property and area. As you see below, the manhole/drain isn't recognised on the properties plot (No.47). We can also see that the property is at the start of the run, not the end (which must be a good thing):



It leaves a question regarding a build-over agreement. Would my proposed extension go within 3 meters of a public sewer?

Looking at the 2011 sewer transfer regs, it seems the drain/sewer on no.47's plot is not public sewer, and the run through to next door is also not public, but 'lateral':



I 'think' this puts me in the clear, but would need confirming. Does anyone know who I'd need to get out and confirm it? Would it be someone from the Water Company themselves, or just a planning officer from the local building regs department?

 

[Ian H]

I'd just crack on if I were you.