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Plumbing

Can I use an AAV and stub stack on new 1st floor bathroom?

Dan 27/10/2026 - 7.59 AM

Hi guys, I’m adding a new bathroom which will need a new soil pipe connecting just from this room and terminating in the existing inspection chamber on the drive. Other runs into this chamber from the rest of the house have a standard vent above roof level. Question is, does this count as the same drainage ‘system’ and can I therefore use an internal stub stack, or do I need to fully vent? Many thanks

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1 Answer

Evolvembed - Plumbing Heating and Air Con

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Dunstable

Hi, Because the new bathroom is on 1st floor, the answer to your question is NO. For a stub stack the distance between toilet floor level and the underground pipe at the first bend ( the swept bend at the base of the stub stack) cannot be more than 1.3m according to current regulations.

Answered27 October 2026