The reason i had to do this was because the customer refused to go out the roof twice.
How to bring bathroom vents together in attic.
You obviously don t want to dump all that air into the attic.
The 2nd bathroom vent drips on the floor and is ruining the ceiling.
Those swinging flaps are not air tight to say the least.
You can usually find these on back to back sinks.
To be properly terminated bathroom fans should exit the home through stem vents that are specifically used for this purpose.
Nail the lower corners with roofing nails and tar the heads.
Here s the problem your soffit vents are your roofs air intakes and the roof vents are the exhaust.
Any person competent in installing an outside vent either thru the roof soffit or gable hip end of the house thru the siding.
These stem vents should be properly connected to the bathroom ducts to ensure that moisture is traveling to the exterior not the attic space.
This allows both drain lines to tie together in a sanitary cross.
The master bathroom and the 2nd bathroom vent through the roof and through the same opening.
Apply a bead of asphalt roof cement on the bottom of the vent.
When a bath exhaust fan is directed to flow out of the soffit area a ton of this warm moist air wafts back towards the soffit vents and will start to rot your roofs rafter tails along with allowing mildew and mold to start forming on your roof.
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.
Slide the vent under the shingles so they cover the top half of the vent flange.
Choosing a whole house fan.
Bathroom vent exhausting into attic space.
A single exhaust exits through the roof figure a.
This system is quiet too.
Well the bathroom vents if they re near each other could be brought together in the attic and then brought out to one termination point.
It s warm it s moist it s humid and it s going to ruin your insulation s effect.
One could be taking a dump or shower and the user in the other bathroom would nearly pass out from the smells moisture.
Each bath fan should be on a separate 4 or larger duct and the outside vent portion must have a baffle damper to prevent anything from coming into the duct work.
The loop vent is a solution for many freestanding sink codes.
The lower half of the flange sits on top of the shingles.
This setup requires an in line centrifugal fan mounted in the attic drawing air simultaneously from both bathrooms see photo.