I just put in a new bathroom fan and noticed the previous one was vented into the attic. I understand this can cause mold after awhile. I live in WI where we see a lot of snow. I was told the roof exit style ventilation can cause an ice dam, blocking the vent. I assume that the snow melting from the hot exiting air refreezes making the ice dam. So, I'm supposed to run the duct to a soffit vent. But, the area in the attic where the soffits are have very little room to work. I think I'll have to force myself to work in the small space but what are my options?

  • FWIW, I vented out the roof in MN. No problems.
    – DA01
    Commented Mar 19, 2015 at 17:00

1 Answer 1


You should not vent out the soffit if you have soffit vents. The moist air will be sucked into the soffit vents, and cause just as much (or more) trouble as venting directly into the attic.

The best option is to vent out the gable end of the attic. Make sure the ducting is sloped slightly back towards the fan, so condensate can drain. Use rigid metal ducting, not that flexible plastic junk.

  • When I said soffit vent, I meant that I'd install a soffit vent: homedepot.com/catalog/productImages/400/ec/… connected to the fan with ducting. That said, the house does have the soffit vents: scrosroofingcompany.com/wp-content/uploads/2014/11/… My house doesn't have a gable vent though. I consider myself a DIYer but no construction exp. Would a gable vent install be too much for someone like me? I'd assume it'll cost a lot to have someone install one. Sheesh, all this for a fan.
    – vng704
    Commented Mar 19, 2015 at 17:05
  • Installing a vent in the gable isn't that difficult, it's just a matter of cutting a hole and installing the vent hardware. If you paid a builder to do it, they'd likely use a hole saw of the correct size to make the hole.
    – Tester101
    Commented Mar 19, 2015 at 17:10
  • 1
    Not clear to me if the OP has gable ends or a hip roof. Agree that the gable end is the right place for a vent, but if it has to be soffit, then be sure to block intake vents nearby. Commented Mar 20, 2015 at 14:02
  • What if your gable end rafters have vents? :p Commented Nov 20, 2016 at 3:54

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