Underground drainage done - look ok to you guys?

Appreciate this is a dangerous game to ask some of you pros to critique my DIY drainage, but would like some feedback if anyone can see any glaring errors with what I've done before BC come round.

At the front I've dug down, cut into the existing clay surface water drain (as per plans submitted to BC as no room for soakaway at front), connected a 450 inspection chamber at 1.1m depth with the pipe coming up to be connected straight to the gutter drain pipe:



At the rear I've broken into the existing clay fowl pipe with a Y piece - had originally planned to go straight into the original inspection chamber and create a new channel but BC suggest the Y connection and another manhole to save digging/drilling through the thick concrete wall of the inspection chamber.





Runs along to another 450mm inspection chamber which was simply to help me with the angles and not want to dig up/remove existing paving and decking. Then the waste water connections start with a bottle gully, before a 300mm inspection chamber at 0.5m depth with a swept 45 angle to get me round the tight spot in-between the neighbours fence and the foundations (The foundations are actually in - just covered with sand as they were done 12 months ago!). Then along to another bottle gully, before the final connection to a sewerage pipe.





Finally, I installed a soak way at the rear for the surface water, this crosses over the sewerage pipe but with about 300mm in-between. I'm a bit annoyed it's wonky, but hopefully it'll be ok for BC.



BC saw the unconnected soakaway on their last visit, and said I could cover it over... hence the partial fill.

Everything has been laid on 10mm pea shingle (2 tons of it). Ironically BC when they came out, after I'd order the pea shingle, said that I could have just used the existing sand as the bed as the regs state material below 10mm.Therefore, subject the BC sign-off I plan to simply back-fill with the excavated sand (removing and stones/waste as I go).

Thanks in advance for any feedback.

Oh no, that’s not good. You need to rip it out and start again.

This is because...








































.. I’m joking, all looks good to me

The wonky long pipe is just a minor thing, but more pertinantly why have you got a bend and a junction just outside of a manhole?

^woody^ said:

The wonky long pipe is just a minor thing, but more pertinantly why have you got a bend and a junction just outside of a manhole?

Click to expand...

If you mean the long radius bend, it's because due to the foundations there isn't enough space immediately on the corner to have sited the manhole right on the corner without having to dig under the fence into next door's garden (and thus leaving the manhole cover under the fence). I thought the swept bend was the best way to get around this situation and should still be roddable from either end.

What would you have done instead?

With both the bend and the junction, it looks like the manholes could have been moved to the side so that all pipes meet in the manhole.

Strictly manholes should be at all major junctions and bends as they are a point most likley to be blocked, but if your inspector feels that the risk of blocakage is low he would normally accept it.