Vent in the Bathroom

art2670

Hello,
I am going through a major renovation in the recently purchase house and have a question with respect to Bathroom Vent installation.
Currently there is no duct that would let all of the moisture outside from the Bathrooom. My contractor is suggesting to install the vent with an exit to the attic. Currently the clearance between the ceiling and the roof in the attic is about 2 feet high. Is this a standard practice? Any advice would be greatly appreciated.

Thanks,
art2670

RippySkippy

It's not in the mid west. I hope he's saying vent it into the attic an then through the roof. I would never vent into an un-heated attic...it's a recipe for disaster. Is it 2 feet because the ceiling is vaulted, or because the fan location is near the edge of the house?

art2670

The roof in the house is flat. It is a duplex house attached from both sides. I suppose the attic is vaulted, since the vent is about four or five feet from the side of the house. What type of disaster are you referring to? I would like to know in order to discuss this issue with the contractor.

Thanks for your reply.

RippySkippy

In the winter time, the moisture from the bath area (read: warm and very humid) is dumped into an unheated space. When the Temperature is sub-freezing, the vapor will make it as far as the first cold thing it encounters; could be a rafter, insulation, the roof deck, anything that's cold. When it warms up, the moisture that's collected will melt and dampen the insulation and ceiling drywall. Insulation is way difficult to dry out, and drywall under insulation is virtually impossible.

I suspect some will say that the roof venting will eliminate the moisture, I wouldn't rely on it. Roof vent's are designed to remove excess heat from the attic space.

The contractor may be looking to take the easy way out. If there's only a couple of feet from the roof to the ceiling, I would think he could fasten the INSULATED flexible duct to the fan housing before installing, and when the roof vent hole is cut, he could reach into the attic retrieve the duct and fasten to the roof vent. He may not have to enter the attic space.

Check out these diagrams and DAGS

KUIPORNG

Looks like the challenge is to cut the roof hole with all the roof materials installed... etc... you know... got to make sure no leak as well.... is this somthing difficult.... than cutting the brick wall ? I cut hole in brick wall before.. it is an hour or more job.... anyway... I agree though... venting to the artic is definitely not a good idea and kind of a short cut....

art2670

Thanks for replies!
One additional question. What do you think about ductless fans? It is another option that was presented to me.

Thanks!

MechanicalDVR

What is the point to a ductless fan? Kind of like a hamburger without meat.

slakker

Ductless fans may be good in a smoking room but in a bathroom, at best it'll make the stick from a "number 2" go away quicker...

AtlanticWBConst.

NEVER EVER Install any exhaust venting into an attic. Especially, a bathroom exaust vent. A ductless fan would not be acceptable by code for such an application (for obvious reasons).

Frankly, I am quite shocked that any "contractor'' with any kind of a brain would suggest such a thing. (I apologize for my bluntness, but it is, what it is...)
Moist air should always be vented OUTSIDE with an appropriate sized exhaust fan and ducted. The fan needs to rated for the bathroom's cubic area.

__________________
- Build Well -

dmaceld

Does your jurisdiction follow the International Residential Code? If so, note this paragraph from the 2006 IRC.

"M1506.2 Recirculation of air. Exhaust air from bathrooms
and toilet rooms shall not be recirculated within a residence or to another dwelling unit and shall be exhausted directly to the outdoors. Exhaust air from bathrooms and toilet rooms shall not discharge into an attic, crawl space or other areas inside the building."

New work, including remodeling, should be done according to the latest adopted code.