Foul Sewer Advise

[mowgli789]

Hi all,

 

Firstly, I'm not a plumber, so work on the assumption I know nothing.

 

We are building a 2 story extension on the back of our chalet bungalow. Currently the foul sewer runs along the back of the house from one side to another and then away to an inspection chamber on the edge of our property about 19m away. The fall between the first inspection chamber and the one on the edge of the boundary is about 30cm. So significantly less than 1:40.

 

Any new foul sewer will need to go under / through the foundations of the new extension. The length would increase to about 23m. I think that would make the fall about 1:100.

 

Given the lack of fall, and the foundation issue, would an external pumping station be necessary, of with the right diameter pipe do you think the current setup could work?

 

I've attached a quick sketch to better show my issue. 

 

Any advice would be appreciated.

 

Thanks

 

Ben