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Discuss Bathroom Waste Layout - Horizontal Soil Pipe in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net


I would very much appreciate some help/feedback on what I am proposing for my very small ensuite bathroom. While refurbishing it I’m proposing to add a shower. It’s just 1.2m x 1.6m. I have seen similar posts to this on the forum but not quite my situation.

I am proposing to run one 110mm soil pipe in the 180mm (7”) ceiling void, with 1:40 slope, between the joists in the bathroom floor. Connecting the shower, toilet and vanity unit into this soil pipe using 40mm and 32mm boss straps (or boss pipe connectors) for the shower and vanity unit and an 110mm equal branch for the toilet. Please see attached diagrams. The end of soil pipe will be blanked off after the connection for the vanity unit. Due to the limited void the boss connectors will be set as high as possible in the soil pipe but only about ½ to ⅔ the way up soil pipe.

I propose to fit a 92.5 bend (with access point) where the soil pipe goes through the outside wall and run this horizontally (1:40) into an equal branch into the existing stack. I plan to fit a Durgo/AAV on top of the equal branch on the vertical stack as there is a small window directly above the existing stack making a vent pipe rather awkward (and unsightly).

So my questions:-

1) Are my plans realistic, are there any issues I need to address please?
2) I have seen some people advising boss connectors rather than boss straps - what’s considered best?
3) Is the proposed Durgo/AAV on the existing stack sufficient? I could, with a lot of difficultly, put a vent pipe, with AAV, up into the roof space after the vanity unit. If considered really necessary what is the minimum size of pipework required?

Please forgive my non-technical descriptions but I am new to this. I consider myself to be a competent DIYer and would very much appreciate some expert guidance.

Many thanks, Howard


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