Your local AHJ needs to get with the times.
International Residential Code (IRC) 2006
**M1501.1 Outdoor discharge.** The air removed by **every mechanical exhaust system** shall be discharged to the outdoors. Air shall **not be exhausted into an attic**, soffit, ridge vent or crawl space.
Your preaching to the choir I am well aware of the IRC codes.
Charlie, I see it all the time. Most all bath vent fans terminate into the attic around here, even my home that is 10 years old, with no problems, mold or moisture. Some are 20-30 years old, and still working fine. I believe this is an issue dependent on weather conditions and local climates and codes.
I recommended a few months ago at an inspection that two vent fans be vented to the attic or outside because the vent fans did not have any tubing or ducting. So, the repair persons ran tubes through the attic to a flapper/roof vent for both bath vent fans. Later, the owner complained that the flappers were always making noises, and her bathrooms were now colder than they were previously. The rooms got colder due to the “stack-effect”. She had the ducts removed, put short metal ducts above the vents into the attic, and solved her problem. Wind blowing on roof vents will suck warm or cold air out of the venting room. If I lived in a cold climate, I would not like that either.
Definitely not allowed by code here unless it is ducted through the soffit to the exterior somehow. I am guessing there is a climate factor making it OK in warmer places, but the result here would be instant condensation or snow inside the attic when the moist humid air hits the freezing attic air. Also an attic as big and open as the one in Charlie’s pic is pretty rare here, even high attics are filled with trusses.
Yes Erik climate factor makes a big difference. I have been working in attics for over 40 years in one profession or another and I just don’t see damage from bath or kitchen exhaust fans in this area big attics or small ones. The only vent that the local AHJ requires to be external is the dryer vent. Here is a smaller attic from today. Two bathroom exhaust discharging onto the small area as shown.
This one built in 2000 and did have the kitchen exhaust through the roof. The lumber appears as shiny as the day it was installed.
no matter what. I think all venting should go through the roof with the exception probably of the dryer.which it should go to an exterior wall.
For your area that would be correct but what you think don’t count for beans in my area:twisted:
don’t be such a piss head. Are you telling me that in construction that you wouldn’t vent the bathroom exhaust fans to the roof.
If anyone thinks dumping grease laden moist air from a range hood into an attic space is a good idea., what can be said?
Don’t believe everything you find on the internet or even this message board.
Use your head and what ever common sense you have taking into account your local building practices and local climate conditions.
YMMV
A red hat does not ensure a correct answer 
I did not tell you anything I was not talking to you. Your just assuming.!!! I don’t build I just inspect according to the local AHJ requirement. I can explain it to you but I can not understand it for you;-)
OK! Assuming you know all of these.
I have one simple question to ask you… Are you ready?
Here it is…
If you were building a home would you vent the fart fans through the roof?
Yes or No would be good answers.
Yes if I was a builder in my area I would exceed the local requirements;-)
Thank you.
I’m done.
Since Charley brought this up I’m curious how many here;
OR,
I’m#2.
As we all should be.
PS: I knew that question would be asked when I made that post.
It’s called a lead in .
Codes and AhJ requirements are bare minimum standards.
I’m not a bare minimum inspector, and I don’t suggest to my clients they settle for bare minimum standards. 
Since you brought this up I would have to comment what is considered national practice is not always best practice for every area of the country in every instance there are exceptions in numerous cases.
New York Salsa is not considered as best Salsa in the SW.
I have proved my case over time that the amount of moisture discharged into a attic in my area by bathroom exhaust fans is not a determinant to wood based on local weather conditions. We don’t have extended high humidity nor extended low ambient temps.
I use some common sense in my inspecting approach which seems to be lacking by many on this MB.
Can someone please show me a pic of attic damaged in their area from bathroom exhaust fans not discharging to the exterior with a climate the same as my area. I have inspected over 10K homes and I can count maybe two homes with attic damage due to moisture but these attics had no ventilation what so ever. ??? Put up or shut up:p
Yesterdays and I have plenty more and in worse shape. This home just got remodeled so this venting is not a year old. Can’t wait to see what it looks like in a few years. 
Yipper your in
Wis can not compare it to Okla BTW where were the vent fans from the damaged area. I see a soffit baffle were the soffit vents blocked with insulation
Yes they did not install baffles in every bay.
