Drainage

[SlivenClod]

What is the maximum slope allowed on foul drainage lines? I have a sloping site with >2m fall.

House at the top and connection to main sewer at the bottom.

I am guessing a back drop(s) will be required somewhere.

[Jeremy Harris]

11 minutes ago, SlivenClod said:

What is the maximum slope allowed on foul drainage lines? I have a sloping site with >2m fall.

House at the top and connection to main sewer at the bottom.

I am guessing a back drop(s) will be required somewhere.

 

 

Vertical if you wish.  There used to be a maximum slope many years ago, but the regs were changed when it was realised that there was no problem with having a steep slope.  Things like backdrops are now no longer really needed, as you can usually just increase the gradient on the pipe.

[SlivenClod]

Thanks for that.

I can now just use a backdrop at the point nearest the connection to the main to shorten the deep digging.

[PeterW]

4 minutes ago, SlivenClod said:

Thanks for that.

I can now just use a backdrop at the point nearest the connection to the main to shorten the deep digging.

 

Nope... don’t go with a backdrop, just go 45 degrees to get to your invert level from your drain level (easy to calculate as the depth and length are the same) and run in with the slope. Backdrops can block and are a nightmare to install and clear.