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Fixing a discovered bath exhausting to attic

sippycup | Posted in General Questions on

Hi all, I own and reside in a 1943 home in climate zone 4a home, largely renovated but some not details not so well.

I discovered my master bath’s exhaust vent terminates in the attic. No mold issues, and I looked, but still interested in DIY improving this little issue. I would like to both install an in-line check valve and try to vent to the exterior. The attic has soffit vents, a ridge vent, and small-ish gable vents (2x, probably 2 sqft each in area).

My initial plan was to somehow vent through the soffit (cutting into the soffit and installing a vent assembly) , or through the existing gable vent, but I understand many are concerned with re-entry of the exhausted air.

I understand many regard a roof or gable-wall penetration as ideal. However, I am not comfortable with cutting into the roof. Similarly, the gable-wall has asbestos-containing siding that shall not be disturbed.

That leaves the soffit vent as the only viable DIY option (I guess the other option would be to leave it alone).

Just curious of the audience’s impressions. I know that many on this board are prefectionists, I myself am weaning myself of this pernicious habit, but all thoughts would be appreciated 🙂 .

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Replies

  1. Malcolm_Taylor | | #1

    sippycup,

    Venting through the soffits is fine. Try and locate it as far from the exterior wall as possible, and use a termination that directs the air-flow away from the house. Something like these:

  2. sippycup | | #2

    Malcom, thank you very much. I found the following thread:

    https://www.greenbuildingadvisor.com/question/panasonic-whispergreen-with-flimsy-flap-damper

    My plan is to remove one of the plastic "ventilated panels," replace with a "non-ventilated" panel, and install a soffit vent in the style you present. The linked thread mentions 3' from any attic intake location, these steps will buy me 3' with some margin from the remaining soffit ventilation.

    Thanks again!

    1. Malcolm_Taylor | | #3

      sippycup,

      I now have two soffit mounted vents. One for the dryer, and one a bath exhaust. If I go outside on a cold day when either is running I can see the air is being pushed well clear of the house.
      Your plan sounds good!

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