Pipes Beneath Foundation

[photonfoundry]

Hi all,

I'm in the process of designing a simple single storey box extension to be self-built.

I've reached the point of surveying the existing ground and drainage and am trying to plan the foundations. The house has a combined drainage system.

The main thing I'm struggling with is that the current soil pipe runs away from the house cutting across the proposed foundations for a significant length. I haven't dug the entirety of the pipe out to confirm exact depths, but assuming it's at a consistent pitch across the whole length I suspect the current setup is something like this;

I can understand how to deal with the kitchen drain given it's a short section.

I've not approached BC or applied for a build-over(/near) agreement yet, though from looking at the United website I don't think the build-over should be difficult to obtain given I'm not actually covering a public sewer/inspection point/manhole. I've not arranged for CCTV survey yet either.

I'm not sure what the best approach is the to presently combined drain. The gutter portion will be separated off to a soakaway, so it'll just be a matter of getting the soil through and connected.

Is shuttering the pipe and pouring footings around it in its current position unrealistic? I'm worried it might be. Obviously a lintel's not going to cover things...

Will it be easier to redirect this pipe parallel to the wall and have it pass through the rear foundations, before using a couple of inspection chambers to redirect it to the main sewer? I'd imagine that bend would end up quite sharp, however.

Would it be easier to use a strip foundation and guide the pipe through masonry instead?

Very keen to get some advice on this.

 

[noseall]

Hi all,

I'm in the process of designing a simple single storey box extension to be self-built.

I've reached the point of surveying the existing ground and drainage and am trying to plan the foundations. The house has a combined drainage system.

The main thing I'm struggling with is that the current soil pipe runs away from the house cutting across the proposed foundations for a significant length. I haven't dug the entirety of the pipe out to confirm exact depths, but assuming it's at a consistent pitch across the whole length I suspect the current setup is something like this;
View attachment 309060
View attachment 309061
View attachment 309062

I can understand how to deal with the kitchen drain given it's a short section.

I've not approached BC or applied for a build-over(/near) agreement yet, though from looking at the United website I don't think the build-over should be difficult to obtain given I'm not actually covering a public sewer/inspection point/manhole. I've not arranged for CCTV survey yet either.

I'm not sure what the best approach is the to presently combined drain. The gutter portion will be separated off to a soakaway, so it'll just be a matter of getting the soil through and connected.

Is shuttering the pipe and pouring footings around it in its current position unrealistic? I'm worried it might be. Obviously a lintel's not going to cover things...

Will it be easier to redirect this pipe parallel to the wall and have it pass through the rear foundations, before using a couple of inspection chambers to redirect it to the main sewer? I'd imagine that bend would end up quite sharp, however.

Would it be easier to use a strip foundation and guide the pipe through masonry instead?

Very keen to get some advice on this.

The gutter drain will be moved to the outside of the building footprint. His mate next to him can be re-laid along side the external brickwork (once built).
The kitchen drain can be either shuttered and lintelled over or wrapped in compressible material. Failing that, run it straight (not diagonally) through the trench into a mini access chamber and then into the main sewer chamber.

 

[^woody^]