Exhaust fan...exhuast routing?

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Jed1154

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So i moved into a house that is pretty much new. It has bathroom exhaust fans in every bathroom. I found the directions for the exhaust fans and cannot find an answer. Two of them have short pieces of duct coming out inside the cieling...they pretty much just lay there in the dead space. The other fan doesnt even have that much. My question is, is this where the bathroom 'stink' is supposed to go...just in the dead space under the floor or the attic? My older home had a similar setup, and i know it did not exhaust OUTSIDE, but i am not sure where it DID come out in the attic, so i was curious.
 

Jimbo

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The "stink" is not an issue. But the moisture exhausted out of the bathrooms is a BIG issue. What you have will lead to mold, mildew, and dry rot problems. You should take steps to route all the exhausts to the outside of the building.
 

Jed1154

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I know it probably doesnt matter, but we don't use them during or after showering.

Its sort of a problem to route them anywhere since they are sort of under the floor on the second floor of the house. Not sure what to do to route them at this point.
 

msimon

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When you say the house is "pretty" new, is it still under warranty? The vents don't sound like they're up to code. Also, did your home inspector miss that one when you were getting ready to purchase the home? My first step would be to contact the builder.
 

Jed1154

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Well, its outside the city limits...im not sure how much code was there. I dont know about all that stuff.

Its not something you can really see. I mean, the inspector didnt pull up the floor or pull down the exhaust vents to check for proper ducting. Im pretty sure there is a lot of stuff that isnt 'to code'.

The house was built in 1999....its out in the country.
 

Gary Swart

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There still should by county and state codes that apply. You're no different than most of the rest of us non-professionals. We really don't know what is proper by code. Suffice it to say, before undertaking any plumbing, electrical, and/or structural modifications, find out what is code before plowing willy-nilly ahead. As far as the exhaust fans are concerned, they must be vented to the outside. What you have now will cause mold in the attic which I promise you do want.
 

Jed1154

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hmmm...well, thats quit an undertaking to get he fan plumbing to the outside, under the floor, especially since there is insulation in between the foor joists. i know its not right, but its not something i can tackle anytime soon. Its been that way for 9 years now, so, i dont know. I can't pull up the floor, there is no way around that. Any ideas?

Can they be vented into the OPEN space in the attic? I ask because we have VERY generos soffits, so the weather outside is the weather inside, that includes humidity. I can't go to the sidewall (12" thick concrete wall + limestone). I have a metal roof, and the floor joists are filled with insulation. The only thing protruding from my roof is a chimney, and one plumbing vent for the entire house.
 
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Jed1154

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So i have been thinking about this. I have three bathroom vents in my house. they vent to the dead space under the floor, between the joists. Its a two story home. The home has no warranty, so if they are incorrect, its up to me to fix them. I understnad i can vent them to the soffit. What do i need to do this? Where can i get the soffit vents? Im going to have to make a 15 foot run to get to the soffit. I can't really go through the roof since its two story and the are on the first story under teh floor. If i cannot get through parallel to the joists (because of cross blocks) then i will have to come up through the floor behind the wall, across it and back down to the soffit...that would be at leat 3 bends. Is that OK?

Whats the solution?
 
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Jadnashua

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Each fan has a limit on the length of the duct run. There is no generic answer. Each elbow effectively decreases the total length as it slows the air flow down. There are standard values of how much an elbow adds to the resistance, but without knowing how much the fan can push, it doesn't mean much.

At least the fan from a full bath is normally run when trying to exhaust the excess moisture resulting from a bath or shower. This is NOT good to exhaust into your insulation. Running it out a soffit vent is akin to dumping it into the attic since the air is likely hotter than that outside, and will come back in an adjacent vent, cooling off along the way and adding moisture you don't want that could condense. You are right that trying to install ductwork in a joist bay that already has insulation in it and you have little access will be nearly impossible without either tearing up some ceiling or floor. The reason you have trouble finding soffit vents for a fan exhaust is that they typically aren't recommended. If you don't have an end wall where you could exhaust them, a good roofer could make a watertight penetration through the roof. Combining the outputs is problematic unless they are designed specifically for it; most fans are not. Fan-tec makes some that use one fan motor, remotely mounted, that can pull air from multiple locations. While maybe tough, venting through a stone/concrete sidewall could be done, but expensive.

It's a tough situation. Code requires a bathroom to either have an operable window or a working exhaust fan (to the outside!), so you technically may not be up to code and that could bite you when it comes time to sell. If you try to dump a lot of moisture into closed spaces, you may end up with mold issues.

Not sure what to do since I can't see what you have to evaluate alternatives. Keep searching, something may click eventually.
 

Jed1154

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When i said dump it to a soffit, i meant actually duct it to the sofft, cut a hole in the soffit and attach the duct to it, so the vent actually goes to teh outside. I don't see how thats any different than going through the roof. Im honestly not sure how many bends i have to make....maybe only one. These fans are not used for exhausting moist air (thats not an excuse). One of the bathrooms doesnt even have a shower. They are not run when the shower is going anyway. My master bath is set up such that its a giant room....but then inside that room is a small room, a very small room with the toilet, that room has a small exhaust fan in it. I don't think its a problem really, the way they are set up, but I would like to make them 'correct'.

Technically speaking, the master bath...the large room has two giant full sized windows in it, the other bathroom with a shower also has two large windows. The only other bath with a fan has no shower.

As an example of what i was thinking of doing, here is a link....i don't think anyone is an idiot, im just putting this out there in case soemone doesnt know what i mean.

http://www.blackenergy.com/index.ph...d=1696&zenid=f5f960734ff006f7c4b0c4b8a2002420
 
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