I have a geodesic dome that needs plumbing. I really do not want to make holes in the side of it for plumbing vent. Is it at all possible to design the venting so it would go outside somehow from below? I am not a plumber and just started learning about it. I threw a quick drawing of what I was thinking with dashed line indicating the venting path via pipes inside the walls. Would something like this work or not?

P.S. I have some guesses of its issues, but I am looking for your answers what is wrong with it and if there are solutions to my problem other than air admittance valves (AAV).

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  • It's like a "whole house island venting scheme". IDK if it could be made code-compliant but it seems like it could be made to work. A couple of problems to solve: 1. The entire vent system needs to drain into a drain. So in your diagram the part under the floor would need to be sloped appropriately and have an exit into the drain system, in such a way that it doesn't become inundated with water. 2. The vent exit needs to be higher. Normallly above the roof line, so gases are dispersed there. Again IDK what code would say in this case.
    – jay613
    Commented Apr 17, 2023 at 13:39
  • 1
    AAVs might be more practical and more readily compliant.
    – jay613
    Commented Apr 17, 2023 at 13:41
  • Is there a good reason for not wanting to go though the roof? There are fitting/devices to seal the hole to be leak free. Your location is probably important to go by the local regulations.
    – crip659
    Commented Apr 17, 2023 at 13:42
  • I don't see any problems with draining as it would go underneath (not part of my drawing), but yes - I wonder what would happen to sewer gasses in my design.
    – i--
    Commented Apr 17, 2023 at 13:43
  • The problem with venting thru roof is also aesthetical. Np good and easy way to hide the pipe inside as my walls are in the middle and not touching the dome sides.
    – i--
    Commented Apr 17, 2023 at 13:47

1 Answer 1


idk code where you are, but in the UK you don't need to go up & over, you could go straight underground if your final waste drops lower than that level [which it almost certainly should]. That way, your little pop-up vent with an AAV would be fine [without an AAV it must go above the roofline.]. The AAV must be at least 200mm above the highest entry point - the wash-basin overflow from your diagram.
You don't need to vent each individual utility, only the final drainage line.

enter image description here

Regular P-traps assumed in all the right places.

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