It eliminates the need for routing ductwork through the house and these fans usually dry the bathroom more quickly.
How to vent a bath fan through the roof this old house.
Heath shows that most bath fans have the fan mounted right over the register but there is an option where the fan is located elsewhere often an attic or basement and is ducted to both the bathroom register and the vent to outside.
This will serve as a reference point for positioning the wall cap.
From inside the attic drive a nail through the roof directly above the bathroom vent fan.
Other venting options includes running the duct up through the roof or down through the soffit.
This involves running ductwork from the fan usually though an attic and out through the roof.
Depending on the location of the bathroom it may be easy to vent the exhaust fan through the roof.
This article describes routing bath exhaust fan duct upwards through an attic or roof space or downwards through a floor or crawl space.
In this video this old house general contractor tom silva shows how to properly install a roof mounted bath fan vent.
If you vent through a soffit where attic vents are often located the moisture will get sucked back up into the attic or roof venting.
In all cases the ducting needs to conduct the exchaust to the building exterior and needs to terminate in an animal proof vent cover.
Vent your bath and kitchen exhaust fans through the roof through a special roof hood.
The best exhaust fan venting is through smooth rigid ducts with taped joints and screwed to a special vent hood.
From the roof find the nail and use the utility knife to cut roof shingles from.
From outside use 4 inch hole saw to cut hole for wall cap.
If you vent through the roof condensation will drip back into the interior.
Here this old house general contractor tom silva shows the proper way to install a bath vent fan.
The master bathroom and the 2nd bathroom vent through the roof and through the same opening.
I recommend that my clients vent their bath fans out a gable wall if at all possible when not using an hrv or erv that is.
Do not vent through a soffit.
In this particular installation tom ran the exhaust duct into the attic and through a sidewall to the outdoors.
Venting through a roof vent or exhausting them in the attic could cause moisture problems and rot.
In this video this old house general contractor tom silva explains how to vent a bathroom fan.
Bathroom ventilation fan duct routing routing a bath vent duct down out or up through an attic or roof out.
Center the nail between two rafters.
If that s not possible go through the roof.