Soil pipe under concrete floor

[LinearPancakes]

So it turns out that the drainage aspects of our plans that our builder is working to weren't really thought out. So we're having to think on our feet as to the best route for the soil pipe to take to the main chamber.

 

Our builders preferred route includes a 9.5m run underneath the soon to be installed concrete raft. It's the shortest route overall and requires only a single additional chamber/change in direction before reaching the main chamber. Other routes are a couple of metres further, require at least one more chamber and run through tighter spaces.

 

Simpler is better, but can't shake the concern that if there were any structural issues with the drain in the future, it would be near impossible to fix them. There are mature trees nearer that route too, hence the need for the [piled] raft. That seems like increased risk for root damage at any joints, etc.

 

I'm sure drains are ran in similar situations all the time, so I'm not sure if I'm just overthinking here. Any advice appreciated.

[RJHumphrey]

Hello, 

There are no dig repair options available, this all depends on the extent of the damage, there are liners that can be inverted into sewers from manhole chambers, which effectively gives you a new pipe inside the existing pipe, also cutters to remove obstructions from within the pipe, As long as you have access, you did mention a chamber.
 

slightly off subject, I am working on a job where a homeowner has lived in a property for a number of years and just started having issues with the shared sewer running under the property. Water company survey the drain and identify a steel pile driven through it. This pile was installed when the previous owner had work done to support the bay window 20 years earlier, the new home owner is liable for the costs to remove this pile. Lesson learnt by me, survey sewers prior to purchasing a property.
YouTube sewer lining.
hope this helps.

[markc]

If you can go around the outside then do it! The extra bit of cost will be outweighed by peace of mind.

couple of years ago saw a new build where drains were run under properties and one needed the whole ground floor digging out after settlement destroyed a pipe run. Then again the mass builder also didn’t dig footings - they heaped type1 on the inside and soil outside to form trenches 🙈

[Russell griffiths]

I like to get a pipe outside as soon as possible, but a run under a slab is very common, just make sure the pipe is fully supported on a bed of weak concrete and fully compacted all around, not pea shingle. 

[LinearPancakes]

Many thanks all. We made a slight rearrangement that I'm hoping will make it a bit easier to take one of the other routes and avoid the roots/long stretch under the raft.

 

Asked the builder for help achieving it, so see how it goes from here. 🤞