I am a smoker who lives on the first floor of a 100 years old 3 stories condo. During the winter, I smoke in my bathroom with the exhaust fan (on the ceiling) turned on to draw the smoke out. Each of the units has its own exhaust outlet on the exterior wall, so I guess the vent pipes should be independent of the other units.

However, I recently received complaints from the upstairs residents for cigarette smoke smell in their bathrooms, which are directly on top of mine. Is it possible the vent pipes are interconnected and it was the normal practice at that era (1910-1820)?

  • how would they know you were smoking to complain to you? Do you have laundry in your apt, or in a common area?
    – dandavis
    Commented Jan 22, 2022 at 2:39

3 Answers 3


Many building like that were built without actual duct work but used the space between the joists, ceilings and floors. Running your fan would increase the pressure in that space and smoke would find it's way through any openings... like your neighbors vents. There is also the possibility that there is duct work but that it wasn't connected right when the exhaust fans were installed or replaced. You'll need to do some investigating to see if ducts are there to your bathroom fan and connected right. Also check the exhaust outlet for ducts being connected to it.

  • I understand your answer, which is very true and my smoke can find its way to the second floor through the ceiling space, but the third floor? Which reported smell is limited to their bathroom only. This really puzzles me.
    – r13
    Commented Jan 20, 2022 at 0:18
  • 1
    It could be traveling through holes or raceways for the plumbing pipes, vents, drains etc.. maybe the second floor people don't notice it or don't care.
    – JACK
    Commented Jan 20, 2022 at 0:41
  • 2
    If the building was build in the 1910's, @r13, it could be balloon framed. That would allow smoke and other smells to travel all the way from the foundation to the rafters.
    – FreeMan
    Commented Jan 20, 2022 at 13:41
  • 3
    If the bathroom exhausts are lined up vertically on the outside wall, yours is switched on, theirs is switched off, and if there is any negative pressure in their apartments created by a kitchen exhaust or an unvented high efficiency water heater or even a window fan in a bedroom ... your smoke could be sucked into their bathrooms.
    – jay613
    Commented Jan 20, 2022 at 15:17
  • 1
    @AloysiusDefenestrate Yes. I can smell myself if I don't smoke for a few days :)
    – r13
    Commented Jan 20, 2022 at 19:00

You're not supposed to build vents like that, but a lot of people build things they're not supposed to. Anything's possible. First thing I'd do is look on the outside of the building and try to find the vent outlet(s) - that'll give you some clues. If you don't see any vent outlets at all, that's also a clue - it could mean that it's vented into the walls, which is a big no-no.


It may not be related to the fan vents at all. Even with the fan on, the smoke smell will disperse in the air faster than the fan will push it out. And once it is outside, it can easily come back in (through their vent exhaust if it's right above yours). When I walk to my mailbox, if my neighbor has a window open, I can smell the smoke smell 100 ft away. When you search online regarding the smell of smoke entering homes, you will find people that complain they smell the smoke from a completely different house even with all windows closed. I used to have issues with carbon monoxide coming back into the house on the 2nd floor through the roof soffits, so I'm sure smoke smell can easily come back in the same way.

  • Thanks. Your answer makes sense in certain times or houses with old windows without a good seal. A stronger smoke smells outdoor and affects locations farther away from the house should indicate the fan is powerful and works.
    – r13
    Commented Jan 20, 2022 at 18:55

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