Current situation

My bathroom looks like this:

bathroom plan + pictures

The problem is that I face some mild humidity issues (on ceiling and tile grout), as it is difficult to extract air after having taken a shower.
Indeed, it happens that the door is virtually air-tight.

This makes that none of the ventilating strategies below is really effective:

Strategy Extractor fan Window Door Result
1 on closed closed Fan is not powerful enough to suck enough air through the door, so the flow doesn't seem sufficient to prevent condensation on walls and ceiling.
2 off open closed Usually not sufficient enough, plus is a bit of an issue in winter as the dormer window can't be open/closed easily (too high); plus leaving it open constantly isn't very pleasant in the morning).
3 off closed open Humidity goes in the flat, and low air circulation within the bathroom makes that there is still condensation.
4 on open closed The air extracted by the fan… is mostly that that just entered through the window, so it's not effective.
5 on closed ajar Works, but the sound of the fan — despite being not very loud — is bothering as the bedroom & home office are located right in front of the bathroom, so still not optimal.
6 off open ajar Most effective solution, yet leads to draught and slamming doors ; plus isn't really possible during winter months.

So I think that strategy #1 would be ideal… should the hallway → bathroom air flow be greater. I don't think a more powerful extractor fan would be of much help in the current configuration… plus it's likely to be even noisier.


  1. Would trimming the bottom of the door (to let more air from the hallway in) be a good idea?
  2. If so, how much should I trim?
  3. Would a circular saw (with a guide) be the right tool to do it?
  • 1
    How humid is the house? When do you turn the fan on? Have you checked if the fan and duct is clean? This link might give some more ideas. diy.stackexchange.com/questions/175284/…
    – crip659
    Sep 11, 2021 at 11:07
  • @crip659 1/ The house is globally sound and dry. 2/ I turn the fan when I enter the bathroom. It can take a good few hours (with fan on/door closed) for most of the humidity to be extracted. 3/ Except a bit of dust and some light cobweb, the duct is unobstructed and the air can flow freely. I've cleaned the fan. 4/ Thanks for your comment and the link.
    – ebosi
    Sep 11, 2021 at 11:16
  • I have also considered removing/thining the skirting board (that is taller than floor level), but 1/ I'm not sure it's a good idea and 2/ I can't seem to be able to remove it without damaging it (or the flooring on either side).
    – ebosi
    Sep 11, 2021 at 11:19
  • The fan is close to the door. Most extra air coming though the door will go right to the fan and not help much. Think a small fan to move the air around the room will help more.
    – crip659
    Sep 11, 2021 at 11:24
  • 1
    A door air vent near the bottom of the door would look better than a gap under the door. Sep 11, 2021 at 11:35

1 Answer 1


Can't tell what's above the room, but if possible, a ceiling vent would be a good idea. As far away from the fan as possible - and it wouldn't look out of place, would save the door, and be simple to change with a piece of plasterboard later if needed.

  • Thank you for the suggestion — I'm sorry I didn't mentioned I live in an appartment, so drilling through floor/ceiling is not an option in my situation.
    – ebosi
    Sep 11, 2021 at 15:05

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