the sewer is very shallow. Currently the TOP of the existing floor is only 350mm from the top of the sewer pipe, by the time you add in B&B depth, insulation, screed, tile you are way under the 300mm neede. So the extension floor would need to be higher than the existing ground floor, would...
I have a shared sewer running parallel to the back of the house (about 0.5 metre away from the house) it runs to properties both sides of me, in a staight line.
I would like to build an extension on the rear of the house, full width of my land, so will be totally over the top of this sewer...