# bathroom vent



## dirk18 (Oct 30, 2008)

Has anyone in here ever had his bathroom exhaust vented through the roof? This is my last option. Right now, I have it running about twenty-five feet across my roof and out the side of the house. I'm getting condensation and a little mold growing on the bottom of my roof.


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## Still Wait'n (Nov 25, 2005)

We usually vented them through the soffit if possible.


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## ESOX (Nov 20, 2000)

mold is exactly why many cities are not allowing baths and dryers to be vented out the soffit anymore. The warm moist air gets pushed out the hose, turns around and rises back into the attic nearby.
You can get a quality roof exhaust vent with a flapper and a hook up for a 3 or 4" hose for around 11 bucks at a roof supply house. (Not a box store, they sell second rate crap for more money).


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## Craig M (May 17, 2000)

dirk18 said:


> Has anyone in here ever had his bathroom exhaust vented through the roof? This is my last option. Right now, I have it running about twenty-five feet across my roof and out the side of the house. I'm getting condensation and a little mold growing on the bottom of my roof.


We just re-did the roof this past fall and yes, the bathrooms in my house are now vented through the roof.


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## Still Wait'n (Nov 25, 2005)

ESOX said:


> mold is exactly why many cities are not allowing baths and dryers to be vented out the soffit anymore. The warm moist air gets pushed out the hose, turns around and rises back into the attic nearby.
> You can get a quality roof exhaust vent with a flapper and a hook up for a 3 or 4" hose for around 11 bucks at a roof supply house. (Not a box store, they sell second rate crap for more money).


We would go though the soffit with a solid connection like a dryer vent. Not actually into the soffit. I would of thought that snow would be an issue when going though the roof.


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## ESOX (Nov 20, 2000)

> We would go though the soffit with a solid connection like a dryer vent.


It doesn't matter how you do it, if you are dumping the air out under the soffit, it will get picked right back up and brought back into the attic. If the roof ventilation system is working correctly, soffit vents are always intakes.


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## N M Mechanical (Feb 7, 2008)

Run it through the roof but get a flapper a must
_Posted via Mobile Device_


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## Still Wait'n (Nov 25, 2005)

This subject sparked my curiosity. So I just got off the phone with our local building inspector. He also says to run the vent out the soffit, and that running it out the roof you stand a chance of having problems with the snow. I brought up the idea of the soffit vents being an issue drawing the moist air back into the attic, and he said that the air is usually disbursed enough before it re-enters the attic. He also says that most contractors will either run them out of the soffit or a wall if they can.


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## N M Mechanical (Feb 7, 2008)

I agree that side vent is the way to go 75% of our jobs are side vent. With the soffit you must block off two around the vent so it is not getting sucked back in
_Posted via Mobile Device_


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## jakeo (Sep 14, 2004)

When buying one......make sure you grt one with a big enough motor to push air period. some are junk and wont bush the air 5 ft. 
Get one a bit bigger in CFM's for the bath size.
This might help you.http://www.bapihvac.com/CatalogPDFs/I_App_Notes/Determining_Air_Flow_CFM.pdf

Also.....if possible, use hard pipe(sheet metal) as much as possible for best air flow.


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## MEL (Jul 17, 2005)

ESOX said:


> It doesn't matter how you do it, if you are dumping the air out under the soffit, it will get picked right back up and brought back into the attic. If the roof ventilation system is working correctly, soffit vents are always intakes.


This


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## Rumajz (Dec 29, 2005)

N M Mechanical said:


> With the soffit you must block off two around the vent so it is not getting sucked back in
> _Posted via Mobile Device_



That's exactly what we have to do in our area to pass inspection.


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## Big Reds (Oct 14, 2007)

Installed two three weeks ago. Simple install which took about 20 minutes each. Bought them from Lowes as a kit. They are very similar to a pot vent. Can't imagine snow would be a problem though. A few minutes of use should clear away enough snow to work properly.


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## jakeo (Sep 14, 2004)

MEL said:


> This


??......


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## jakeo (Sep 14, 2004)

dirk18 said:


> Has anyone in here ever had his bathroom exhaust vented through the roof? This is my last option. Right now, I have it running about twenty-five feet across my roof and out the side of the house. I'm getting condensation and a little mold growing on the bottom of my roof.


I re-read and would bet that there is hardly ..if any air being pushed out of the vent after running 25'....even if run in hard pipe. Thats a long distance for those lil fart fans.


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## MSUICEMAN (Jan 9, 2002)

is the pipe insulated? seems to be a lot of temperature difference there not to insulate. one of mine is not, but i really can't get to it easily. maybe in a couple years when my nephew is a bit older i'll pay him 5 bucks to wrap it.


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## fishenrg (Jan 9, 2008)

Still Wait'n said:


> This subject sparked my curiosity. So I just got off the phone with our local building inspector. He also says to run the vent out the soffit, and that running it out the roof you stand a chance of having problems with the snow. I brought up the idea of the soffit vents being an issue drawing the moist air back into the attic, and he said that the air is usually disbursed enough before it re-enters the attic. He also says that most contractors will either run them out of the soffit or a wall if they can.


Though there are exceptions, in most cases a local building inspector is not who I would go to for building science advice. If I wanted advice on how to meet the code, they're perfect.


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## Still Wait'n (Nov 25, 2005)

fishenrg said:


> Though there are exceptions, in most cases a local building inspector is not who I would go to for building science advice. If I wanted advice on how to meet the code, they're perfect.


I was just trying to satisfy my curiosity on what he suggested. It's actually up to the mechanical inspector. I wasn't trying to make this out to be science either, just trying to help. I can see where people would want to run it through the roof and that's fine.


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## Flyhack (Jul 12, 2009)

fishenrg said:


> Though there are exceptions, in most cases a local building inspector is not who I would go to for building science advice. If I wanted advice on how to meet the code, they're perfect.


Agreed. Yes they know the code, but everyone should know that building code is the *minimum* requirement. They can't tell you how to exceed it. That is the job of a design professional. In many cases exceeding the minimum requirement is highly recommended.


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