Planned extension too close to sewer?

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Kent
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Can anyone please offer (or point me to) guidance on building an extension close to sewer run? Specifically, how close can the extension get to a sewer pipe (serving about 6 - 8 properties) that runs across the width of my back garden and is about 2.5m underground. Thanks.
 
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call your utility company and ask about buildover agreements..
 
Can anyone please offer (or point me to) guidance on building an extension close to sewer run? Specifically, how close can the extension get to a sewer pipe (serving about 6 - 8 properties) that runs across the width of my back garden and is about 2.5m underground. Thanks.
2.5m wow!

Get your designer to do some design work and make some calls.

How far away from the existing building line is this sewer?
 
I was allowed to bridge over, which resulted in the extension being a little larger..GREAT.
 
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standard guidance is normally for foundation to go below invert level of sewer where within 3 metres of sewer. Obviously this would likely be a pile foundation required for theses depths if following the above guidance.

As mentioned above submit a build over app and then take it from there, the water authority will have experienced theis situation before and should be able to advise.
 
What you need to do depends on your water authority. Many I think are OK, but in the South West they want you to get an extra mortgage to pay for replacement of their knackered sewers on your property.
 
What you need to do depends on your water authority. Many I think are OK, but in the South West they want you to get an extra mortgage to pay for replacement of their knackered sewers on your property.
I don't blame them.

Better to renew what is going to be below your new building rather than the water company demolish your pride and joy to get at their property.

We always advise renewing whilst we are on site with the digger etc.
 
Thanks all for the very informative replies.

It's early days as we're looking at several options to create more living space but I will call the water company (Thames Water) and hear what they have to say.

At the nearest point, the sewer is currently approx. 5.5m from the rear wall of the property. I'm thinking of extending out by approx. 4m so won't be bridging the sewer.

Interestingly, there is another sewer run, which runs beneath the side drive alongside our bungalow and joins the back garden sewer. This part of the sewer system is less deep (about 1.5m I guess) and much closer to the property's side wall - about 1m. Until fairly recently, all these sewer pipes were private.
 
What you need to do depends on your water authority. Many I think are OK, but in the South West they want you to get an extra mortgage to pay for replacement of their knackered sewers on your property.

With Severn Trent I was allowed to build foundations down to the load line from the sewer invert, i.e. to a 45 degree line upward from the invert, the idea being that load is transmitted downwards through the ground at 45 degrees.
 

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