The best exhaust fan venting is through smooth rigid ducts with taped joints and screwed to a special vent hood.
Bathroom vent through attic.
The master bathroom and the 2nd bathroom vent through the roof and through the same opening.
Venting through a roof vent or exhausting them in the attic could cause moisture problems and rot.
The vent hood will have a little flap that opens when air is blowing through the vent but at other times it will remain closed.
The 2nd bathroom vent drips on the floor and is ruining the ceiling.
Bathroom ventilation fan duct routing routing a bath vent duct down out or up through an attic or roof out.
Because the fan is in the attic you ll hardly hear it.
The 2 pipes one a 4 master and the other a 3 2nd do not go through the ceiling but into a common box that goes through the roof.
Either way the vent will have to go directly to the outside and installed with a vent hood cover.
If you vent the bathroom exhaust fan to close to the soffit vents which are vented plates under your homes outer edge and roof your home the air can be sucked right back into the attic from the soffit.
Can you vent a bathroom exhaust fan into the soffit vents.
In all cases the ducting needs to conduct the exchaust to the building exterior and needs to terminate in an animal proof vent cover.
No you cannot vent the bathroom exhaust fan into the soffit vents.
This article describes routing bath exhaust fan duct upwards through an attic or roof space or downwards through a floor or crawl space.
Look for the special fans starting at 160 at heating cooling equipment.
You mount a switch in each bathroom.
Vent your bath and kitchen exhaust fans through the roof through a special roof hood.
This system is quiet too.