GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Bath fan to nowhere

user-6504396 | Posted in Mechanicals on

I first have to say that I really appreciate this forum and all to contribute to it.

My question has to do with repairing a bath fan in the house we are living in. I opened up the fan in an attempt to find out why I wasn’t getting any air flow through it. I found out that when it was originally installed no duct was ever attached. I can reach through the hole and grab the insulation! The insulation was packed right up against the flapper valve, keeping it from opening. The good news I guess is that not a lot of hot humid air wasn’t being dumped into my attic space.

I am looking at alternatives for repair. The attic space is only over the master bath and closet space and it is not very tall, maybe 3 feet at the peak. It is not accessible without cutting a hole in the ceiling. Then routing the duct work in there will be tricky. Are there any other good options? The bathroom is on the upper floor and has an exterior wall.

I guess the easiest solution would be to plug up the hole and shower with the bathroom doors open.

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. Expert Member
    Dana Dorsett | | #1

    What climate zone?

    In not-so-snowy areas going through the roof is fine, but in snowy or very cold areas there are good reasons to look for a horizontal exit plan, to avoid condensation running down the duct into the fan, and to avoid starting ice dam problems by melting snow at the roof vent.

  2. user-6504396 | | #2

    We are in climate zone 4C, marine. We don't get much, if any, snow. The roof is cement tile.

    I was hoping maybe there was an option that could fit in a 2x6 wall and vent horizontally, but then routing the power to it might be challenging without getting into the attic space.

    Would it be possible to take out the existing fan, cut a hole in the soffit for a proper down vent and install an insulated flexible duct without ever getting into the attic space? The soffit is only about 4 feet from the fan. I'm just not sure it can all be done from below the ceiling plane. There appears to be a 2x? running along one side of the fan opening, not the other 3.

  3. GBA Editor
    Martin Holladay | | #3

    If your roofing consists of concrete tile, I don't suggest that you vent the fan through your roof -- although it's certainly possible to do so.

    It's worth mentioning that remodelers cut holes in drywall all the time to improve access. It may seem daunting, but if that's what you need to do to get into the attic, you (or the contractor you choose to hire) can certainly do that. It's fairly easy to repair drywall.

    The good news is that I don't think you need to get into your attic. Instead, install a new wall-mounted exhaust fan on the exterior wall of your bathroom. Remove the ceiling-mounted fan, add insulation in the void, and patch the hole in your ceiling.

  4. Robert Opaluch | | #4

    I would suggest looking carefully and pushing upwards on the ceilings in closets on the second floor to check again that there is no way into the attic. Sometimes attic hatches are difficult to notice. I missed one once!

  5. user-6504396 | | #5

    You've given me some good options to pursue here. The main reason I'm trying to avoid cutting into the drywall is that it is textured. I've never had good luck trying to match the texture or make the repairs disappear. Making a hatch out of a removed piece of drywall may also be an option here.

    Thanks for the input, I appreciate the help!

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |