Water from Bathroon Exhaust Fan


  #1  
Old 11-25-04, 05:53 PM
RIGS26
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Water from Bathroon Exhaust Fan

I was wondering if anyone has an advice/tips for the following issue.

Water has been dripping out the bottom of the bathroom exhaust fan and damaging the dry wall around the vent. I originally thought it was a leaky roof, but after further inspection I believe it is condensation that is freezing in the attic where the vent goes. When the temparature warms up, the water leaks back down after thawing. Does this sound plausible? I live in Colorado, and the dripping seems to start after a big snowfall and then a warmer period.
Thanks for any advice to remedy this problem.
 
  #2  
Old 11-25-04, 07:25 PM
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IHI
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That's exactly what is happening. Code here requires us to installed insulated elephant ducting and have the bath fan vent to a outside wall, not soffit or roof vent.
 
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Old 11-25-04, 07:27 PM
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RIGS26,

First off is the exhaust vented to the outside or inside the attic?
What size is the bathroom?
What's in the bathroom? Tub, shower, whirlpool, etc.
Is the current fan of proper size?

What it sounds like it is just going into the attic.

If you would look at what I provided here, you should be able to rectify your problem once and for all!

I think this will help....

http://www.shopfnc.com/bathfan1.htm

http://www.doityourself.com/electric...exhaustfan.htm

http://www.lowes.com/lkn?action=howT...c=howToLibrary (it shows soffit vent option)


1. Exhaust airflow must take the air all the way to the outside of the building.
2. Duct runs should be short and as straight as possible.
3. Use smooth, rigid ducting whenever possible.
4. Slope ducting to the outside to allow any condensation to weep to the
outside of the building.
5. Ducting running through unheated spaces must be insulated.
6. Exhaust hoods must prevent birds or animals from entering.

Only apply what seems important to your needs,

It's not that I always want to use larger fans but depending on the use and size of room, it is essential to avoid problems. I have had clients use 50 - 110 cfm units and when the family takes long hot showers, they are having problems.

It's an issue that needs to be addressed and when one installs a steam shower bath, heated whirlpools, it's even more critical.

Trouble with fan sizing, they don't take into account what is acually in the bathroom, like 2 sinks or one, like 3 fixture bath, 5 fixture bath and how many are in the family. These factors are more important than the actual size of the room. To top it off, then you get a house full of company, then what? The other issue is that if a family is taking more showers than baths, more moisture is emitted into the room, again, this is more important than room size.

Another issue is vaulted ceilings - or taller than 8' is also an issue so this is another factor. 9 or 10 ft ceilings create more need for larger fan size.

I do agree though that trying to get a quiet fan is the hard part as they are more expensive but what is more important?

Good site for bath fan sizing,

http://steamsaun.com/panasonic/sizing.html

Good sites to look at sones

http://www.broan.com/product-categor...CategoryID=501

http://www.positive-energy.com/pages...nCeiling2.html

I prefer Panasonic but Nutone-Broan are just as good. It's a matter of quality versus price, as always.

Hope this helps!
 
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Old 11-25-04, 08:40 PM
RIGS26
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Thanks

Originally Posted by IHI
That's exactly what is happening. Code here requires us to installed insulated elephant ducting and have the bath fan vent to a outside wall, not soffit or roof vent.
Ill have to look in to possibly getting a different kind of ducting. What we have here is very thin and flexible. Do you think wrapping the ducting in a blanket would help?
 
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Old 11-25-04, 08:44 PM
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RIGS26,

Wrapping it may help depending on the length.

Is it sloping the wrong way?

Is the exhaust fan of proper size for length?

Is this vented thru roof or out through the soffit?

If it is just vented into the attic then you need to correct this.
 
  #6  
Old 11-25-04, 08:50 PM
RIGS26
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Vented into Attic

Thanks for your help! Believe it or not code here in CO says it's OK to vent right into the attic. Doesn't seem right to me. I think the fan is the proper size. It is a small bathroom with tub/shower. The ducting goes about 6ft. straight up in the air with a little bend at the bottom near the fan unit.
 
  #7  
Old 11-25-04, 09:06 PM
RIGS26
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Possible Solution?

Would this work?
Shorten the ducting and insulate it. The moisture would vent into the vaulted crawl space/attic. We live in a dry climate, 11% humidity (the reason they allow the ducting to stop in the crawl space). I'm not so sure I would be able to get the ducting outside plus the length would be over 10 ft. and I'd still have a freezing issue.
Thanks again.
 
 

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