2 soil stacks 1 vent - will it work?

[mrose1976]

Hi,

I'm wondering if this is allowed or will work in the UK. We currently have all our waste water connecting to a single vented stack. The pipes from the toilets etc connect to the vertical stack via a horizontal pipe as you would expect. I'm about to renew all the soil pipes. We have 2 entry points in the ground to connect to. One is the current stack connection (outside), one is currently not in use (inside). The one not in use is essentially internal now having had an extension added many years ago - its in the garage. So, what i'm thinking is to divert the soil into the internal sewer connection and keep the outside vertical stack as the vent. So i have 2 questions. Will it work? And, is it allowed under UK regulations?

I've added a rough sketch of the current and proposed situations.

thanks in advance,
Mike

 

[Ben-gee]

Yes it will work fine if your direction of flow is marked correctly.

 

[ShaunCorbs]

As above I would install a durgo / aav on the left hand toilet also

 

[fowlerboi]

Definitely need a durgo. Think you're allowed something like 6m of unvented pipe run but you would only ever do that last resort. You would never get away with 2 toilets connected to one pipe with no vent, thats asking for issues

 

[mrose1976]

Thanks, I think its a case of stick with the existing then. I might struggle to get an AAV fitted to 200mm above the wet entry point. I assume the wet entry point is where the toilets connect to the soil pipes?