This morning after I sanded the floor in the bathroom (prior to laying underlayment for cermanic tile) I made so much dust that I started the bathroom exhaust fan (I know, they’re not made for dust). Anyway, about five minutes later I hear this “ping, ping, ping” noise. From one corner of the celing fan a rather rapid drip was dropping. Now I’m sure it is condensation… but how to stop this? The exhaust pipe goes into the attic (not through the roof) so obviously the nice warm air that I was exhausting through the fan just condensed in / on the pipe. Mind you it’s 7 degrees here today (Brrrr.).
Our guess is that the warm humid air had been drifting up through the exhaust fan and as it got into the pipe it formed frost and then when I turned the exhaust fan on it warmed and melted the frost which then of course dripped back down and melted through. So what I was wondering was whether there was a way to prevent this. Any suggestions? Thanks.
Replies
Chris, Vent it out the roof or wall and insulate the pipe. If going out a side wall, pitch to the outside.
Remodeling Contractor just outside the Glass City.
Quittin' Time
Ditto to what Calvin said.
That moisture is also slowly soaking your insulation up there and probably the wooden structural members. If it gets bad enough, your drywall or plaster ceiling will come down.
Use rigid pipe (leave the flex tube stuff on the shelf) and insulate it.......or buy rigid insulated duct and use that.
I prefer venting out the roof whenever possible and practical.
I have basically the same problem. I just bought a 20 year old house that they have both exhaust fans venting directly into the attic. Not sure how they lived with this for so long. The best part is is a 90 degree elbow bend in the flex tube where it's collects water from all the humid error.I was wondering if PVC would make a good vent tube? Insulated of course.I would prefer to vent out the roof, but worried about leaks. I guess I will go out the gable wall that is only 5 feet away.Is it possible to have two fans from two different bathrooms (both within 8 feet of each other) exhaust out of the same vent? This would be ideal as I really don't like the look the vent is going to have on the gable wall.
Insulate the duct and direct it out of the building envelope. Mold will follow the condensation if you don't. If there's a gable wall with 15-20 feet, shoot it out there, if not, the roof is you next best bet.
For insulation, I've used the blankets made for water heaters, cut them into strips, and attach using foil tape; don't use duct tape, it will fail eventually.