Drainage layout advice

[Daveo119]

Hi,

can anyone advise if the layout shown in the drawing and photo is likely to be ok? I’m in the process or replacing the drains in advance of new patio. When I dug it out I discovered a combination of 45deg bend and 90deg junction just before the run into the sewer under our extension,with no access. I’m trying to put it back with better access but constrained by the high invert (approx 350mm below DPC), and space to get the access chamber any closer to the house. The run into the sewer has no access so I assume it’s a 45 deg junction to the main. We have access to a manhole approx 5m higher up the main.

BTW it’s a combined system, I understand it’s been this way since the house were build in 1920s. Ground is heavy clay so soak away not an option.

Many thanks.

 

[^woody^]

Looks ok if the falls work.

Remember to trap the Acco's

 

[Daveo119]

Thanks. In the end I couldn’t get the falls to work so had to change the layout slightly. I end up with the gullies abutting the house about 90mm below DPC. Not what I wanted but it’s similar to how it was for the last 20 years.