Make sure that the duct is mechanically attached to and sealed to that exhaust hood. If it were to fall back into the attic, all that bathroom moisture will most likely rot out your roof. Seal the fan box itself and seal it to the bathroom drywall. Then bury it all heavily under the attic insulation. I always prefer to run ducts down through
The extractor fan (exhaust fan) removes humidity and moisture from the bathroom. The fan sucks in air from the bathroom and blows it out of through a vent that is runs behinds above the ceiling. It works in the same way that a kitchen exhaust hood does except moisture is being moved instead of smoke.
The exhaust ducts can discharge through the roof, soffit or gable siding -- but a dampered Vent Hood should be installed as well. If this installation is to be done by an average Homeowner or Handyman, I typically recommend a siding-mounted vent.
Proper bathroom vent / exhaust fan placement becomes critical if you have any sources of hot, moist air in the bathroom area (tub, shower, steam room, etc.), and the best strategic vent location would be directly above or as close as possible to that source, but still high up.
Q: I currently have a bathroom with no bathroom fan in it. I don't have a gable wall to install the venting into and I don't want to put another hole in my roof. Is it better to vent through the soffit (putting in a new vent specifically for the fan), or run the venting pipe up near an existing roof
Vent your bath and kitchen exhaust fans through the roof through a special roof hood. Venting through a roof vent or exhausting them in the attic could cause moisture problems and rot.