Building near a sewer in 1998

[ConfusedBuilder]

We have had some issues with our neighbour during our planning application (we tried everything to get them on side). Long story, short, we have approval but we know they are going to cause trouble with the Part Wall Agreement (they already signed up to a Surveyor) so we are looking at ways of reducing the scope of issues/cost.

There is a ~100mm clay sewer line that passes across our property, into theirs and along their brick extension/conservatory built in 1998. This sewer is about 1.45m down, less than 30cm from the extension and the main property foundations are 90cm deep.

How deep would they have had to built their foundations for the extension/conservatory?

I would be eternally grateful for any help​

 

[Notch7]

We have had some issues with our neighbour during our planning application (we tried everything to get them on side). Long story, short, we have approval but we know they are going to cause trouble with the Part Wall Agreement (they already signed up to a Surveyor) so we are looking at ways of reducing the scope of issues/cost.

There is a ~100mm clay sewer line that passes across our property, into theirs and along their brick extension/conservatory built in 1998. This sewer is about 1.45m down, less than 30cm from the extension and the main property foundations are 90cm deep.

How deep would they have had to built their foundations for the extension/conservatory?

I would be eternally grateful for any help​

in theory 150mm below invert level and or subject to ground conditions

if its a conservatory with no building regs it will be whatever the builder felt like doing

 

[^woody^]

How deep would they have had to built their foundations for the extension/conservatory?

Now, 1.40m, then 0.6m.
Or now 1.40m, then 1.40m.
Or 0.9m then and now.
Or 1.10m now and then

It depends on your or their persepctive and purpose for asking.

Tip, dont serve a PW notice. Assume your foundations will not be as deep as theirs, whatever they are.

 

[tony1851]

I suspect the OP is concerned that he needs to form the foundation at least as low as the drain, but that will possibly mean that his foundtion will then be lower than the conservatory foundation? in which case the Act would apply?

 

[ConfusedBuilder]

I suspect the OP is concerned that he needs to form the foundation at least as low as the drain, but that will possibly mean that his foundtion will then be lower than the conservatory foundation? in which case the Act would apply?

For our design we wont need Party Wall Agreement for the actual building but Thames Water want the pipe reinforced as we will be building over it

 

[^woody^]

For our design we wont need Party Wall Agreement for the actual building but Thames Water want the pipe reinforced as we will be building over it

Do you mean they want you to bridge over it or reinforce it (encase in concrete)?

 

[Ian H]

Or reinforce it internally with a liner.

 

[ConfusedBuilder]

Or reinforce it internally with a liner.

Do you mean they want you to bridge over it or reinforce it (encase in concrete)?

Apologies, I should have been more accurate - Bridge over and pea gravel

 

[ConfusedBuilder]

Thank you all for your input, it is much appreciated

 

[^woody^]

Sorry I half typed a reply but did not send at the time.

Normally, you could use an argument that at the time you did not think that you needed to dig lower than the neighbour's foundations so the PWA would not apply.

But in this case, as the prestart design work and application to the water authority clearly shows that you are aware that you need to dig to 1.5 meters, then as there is no reason to suspect that the neighbour's foundations are that deep too, you can't use that argument.

You could wing it and blast ahead, but that would need you to risk assess the chances of the neighbours trying to stop you with an injunction.