extension close to minor sewer

[andrewf75]

Hi all,
Our builders are starting work on our extension on Monday morning and we have just found out through a neighbour that a sewer pipe runs along the line of where we are building up to. They did the same but before the transfer of sewers to public ownership. So basically its probably 20cm max away from where we want to go out to and its about 50cm below ground. We submitted full plans and the sewer is on no maps so if it wasn't for chatting to the neighbours we wouldn't have found it til digging the foundations. Its a red clay pipe.

Obviously we need a build over agreement, but is this going to delay us or can the builders get on with digging out the foundations while we get the application in? Any idea how long it may take?

Or will they even let us build that close?

Really worried about this. Help!!

 

[tony1851]

From a practical point of view, it shouldn't be a problem as long as the foundation is at least as low as the invert of the drain - which it almost certainly will be - and as long as the drain is adequately protected during the build, and carefully backfilled.

But strictly you will need an agreement from the utility co., and that will incur delay and cost. They can also request a survey of the drain = £££.

Many people just get on with the build and don't open cans of worms.

 

[DevilDamo]

You should apply before any works start on site. This could affect the contractors quote so they should have carried out a few checks too.

Apply to Thames Water here...

https://www.thameswater.co.uk/developers/693.htm

It can take up to 28 days but can be sooner if Thames Water are provided with the application form, payment & drawings. The application few is approx. £300.00.

I'm surprised Building Control didn't pick it up. If it wasn't picked up as a condition, they'd normally just make you aware that sewers were transferred, which may now warrant approval.

 

[andrewf75]

Thanks. We're keen to do it by the book really, but I guess we'll see what the builder says when he arrives on Monday. I suppose we could just pretend we haven't found the sewer. How closely do building control inspect the footings?

 

[andrewf75]

I'm surprised Building Control didn't pick it up. If it wasn't picked up as a condition, they'd normally just make you aware that sewers were transferred, which may now warrant approval.

They didn't pick it up because there is no official record of the sewer!

This thing must happen all the time. So if you're digging the foundations and find the sewer do you really have to stop work til the application is approved?

 

[DevilDamo]

They would check the excavations are deep enough... for the whole extension & would then check they've been concreted... for the whole extension so they would pick up an existing (public) sewer.

In response to your last post... like I said, if it's not mentioned as a Condition, it is usually mentioned as an informative and to make you aware there may be a public sewer & approval may be required.

 

[andrewf75]

They would check the excavations are deep enough... for the whole extension & would then check they've been concreted... for the whole extension so they would pick up an existing (public) sewer.

But the sewer runs just outside the proposed extension so how would they pick it up unless it is exposed?

 

[DevilDamo]

Oh right. In that case they may not. Just hope the sewer isn't damaged by any of your works that could result in enforcement action being taken. For a public sewer of 150mm dia. Thames Water usually ask for a min. 600mm cover from the edge of the foundation to the edge of the sewer. Will you have that?

 

[andrewf75]

doubt it - if its 200mm out from the line of the extension 500mm deep, our footings are supposed to be 900mm deep. Would have to do some maths, but I think it would be closer than that!

 

[DevilDamo]

Well the protocol is if you're building over or within 3m so you know you'd have to apply to Thames Water & 99.9% of the time they approve applications. They're also helpful in advising once the relevant documentation has been provided.

 

[andrewf75]

I'm sure they would approve, especially as next door have done the same albeit before the rule change in 2011

But my worry is delay. The builders are supposed to be starting Monday. They have some demolition to do and then dig the footings. Do you think they can do that while we apply?

 

[noseall]

Just crack on!

Inform the builder there is a drain present and he will be happy with this info'. I would not be at all fazed by such a shallow drain and would just dig out and concrete the footings. If the drain was disturbed or damaged then we would do a repair.

If you intend utilising this drain for your own purposes then just apply for the permissions, or get your build over agreement in due course.

A lot of this type of work is common sense. As long as your builder is not slap dash and shoddy then he will have the brains and skill to deal with the drain as and when he needs to.

All the water authorities want is for the drain to be in as good a nick as it was before you started or better. If you can achieve this then don't lose any sleep over it.

Had the drain been 300mm wide and 2.5m down (like on our current dig) then I would be a tad bothered.

 

[andrewf75]

Thats what I want to hear, thanks very much. We don't need to use the drain at all as our manhole connects to a completely different line and we will just connect into that.