Sewage on extension with external insulation

Hi
We are currently putting in a downstairs toilet into our converted garage. The builders have been found out as dodgy and while I was at work put the sewage pipes from the toilet through the rear wall and to the sewage system OVERGROUND. We are a bit shafted now as I, stupdily assumed the system had been put in underground etc.
The reason they said they did it this way was because the ground level where the toilet is is lower than where the sewage tank is - does actually seem to be the case.

I am looking for solutions. We have external insulation so one option we are thinking of is running the pipes through the insualtion and directly into the tank. That is, to excavate the insualtion, run the pipes against the wall of the house and then replace the insulation, render etc. The pipes will no longer be exposed. There are obsivious issues if there is a leak but I am stumped for money and it is cheaper than the digging option.
Also, this is how the sewage from upstairs WC is taken from house (i.e. within insulation). does this seem viable option. Really appreciate suggestions! (Apart from fire the builder!)

Who designed your sewage system?

Who is overseeing your build?

Is a professional on board?

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.

We have an engineer signing off on the different stages. I think there were a lot of assumptions made - he assumed they were running the sewage pipes under the suspended floor to the tank at the back. It was only when they threw this up that the issue was raised.
I know the next comments will be that this could be avoided by getting professionals/suitably qualified people to plan each bit to the t and to stand over the build. Reality is that I got a builder to come in a quote for doing a garage conversion and I hired an independent engineer to keep an eye on the construction and sign off on the different stages. The reality of this scenario is that unless the engineer is there every minute of the day things will go missed. I am annoyed that this wasnt spotted before this stage but again its all assumptions assumptions by everyone with no one accepting responsibility.
The issue is there now and I am looking for advise on solving the problem and not advice on best practice. Would appreciate any help.

Hi CBGB

I didn't comment, I asked three questions.
This is not something that could have been missed.
It is a simple matter of matching levels to allow a self-cleansing fall.
Here are two more questions to try and zero in on the responsibility for this.

• Have you no other downstairs loo that this pipe could go into?
• Why isn't the new loo at the same level?

Choose which of the builder or engineer you want to pay for this error and threaten to sue them unless its put right.
Unless you were standing over them forcing them to do this work in this specific way I would find it very hard to blame it on you.
Unless there are previously issued engineers drawings showing the loo in at the wrong level I think the fault lies with the contractor.
In the absence of such drawings instructing the builder to build in this spefic fashion, the engineer may be able to claim its not his responsibility.
If the builder acted without even engineer's advice, the contractor should re-install the loo to the correct level since he is obliged under law to build compliantly.

Let me end this comment by stating that the reason I always advise people to employ competent building professionals is to help keep them out of sticky situations like yours.

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.