New Wc soil pipe run and regulations

[Davidalexjeffs]

We are installing a new ensuite on the top floor of a victorian terrace. Soil stack is to the rear and we need a 11-12 meter horizontal run with two vertical drops. I understand the fall required for the horiztonak run, I just need to know if I need to add a top vent- see picture
Or can I get away with a durgo valve at the top?
Happy to run either.
Excuse the rushed drawing!

I need an expert!

 

[Riley]

You will struggle with those lengths. Usually about 7 to 8 m is kind of tolerable . You will likely have to get that signed off by local building authority as a new ensuite would be notifiable

 

[gingalig]

Cant you go straight down and put in a couple of inspection chambers and then link to the existing, thats going to really ugly and a right bugger to rod if you have any issues.

 

[Sharp Point]

I had a situation like this a few years back and the BCO wanted me to fit rodding eyes on every external corner

 

[Riley]

I can’t help but think that the water is going to get away and leave the nasty in the second horizontal

 

[WC1]

BCO will want it roddable as above, you might get away with a durgo, but a properly fitted open vent gives a better result in the long run. If you're keeping the place I'd suggest open vent.

 

[Riley]

Also as mentioned this is a notifiable install so please do it for your own house and home insurance sake

 

[WC1]

Or a plumber on a self cert scheme will be able to take care of all that for you...