# How would you vent this bath fan?



## wopachop (Feb 12, 2008)

Yes both have showers. Thinking about turning the left side soffit into a hidden sealed dual exhaust. Downside would be losing that sq ft in attic ventilation.


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## tenon0774 (Feb 7, 2013)

wopachop said:


> Yes both have showers. Thinking about turning the left side soffit into a hidden sealed dual exhaust. Downside would be losing that sq ft in attic ventilation.


:blink:

Attic ventilation?

No back flow considerations through a "dual soffit exhaust"?

How about discoloration of that "secret" exhaust through the soffit, based on all that moisture exiting the building and condensing on the exterior "screen" or interior attic space?


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## CarpenterSFO (Dec 12, 2012)

Not only would the roof be better, it would be easier too. Just enough pitch to flash reliably, little enough pitch to work on easily. And no crawling around in those shallow eaves.


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## Tinstaafl (Jan 6, 2008)

tenon0774 said:


> You probably don't like skylights either, eh? :whistling


They're very pretty when done tastefully. 

But honestly, do you really feel that they're as impervious to problems as uninterrupted shingling? Come on, man.


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## Jaws (Dec 20, 2010)

Tinstaafl said:


> They're very pretty when done tastefully.
> 
> But honestly, do you really feel that they're as impervious to problems as uninterrupted shingling? Come on, man.


I agree, uniform shingles are ideal, but every roof has penetrations. 

In my experience, its all about the proper flashing. Ive seen chimneys without crickets that are 30 years old not leak, with step flashing.

It is ideal to vent through a gable if accessible, roofs not a problem to me though. Unless its an ascetic problem.


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## tenon0774 (Feb 7, 2013)

Tinstaafl said:


> They're very pretty when done tastefully.
> 
> But honestly, do you really feel that they're as impervious to problems as uninterrupted shingling? Come on, man.


True. Not as "impervious" to water damage as "uninterrupted" shingles.

No, skylights are NOT impervious to problems. I've replaced a few.

The UV light, blows the gaskets after 10-15 years.

Three tabs have a "guarantee of 25 years". *

Laminated, 35 years-50years. *

I've also helped installed Eco-Star, when they first came out. 50 year warranty* 

:whistling

I would rather, go after a reputable skylight company, to replace a frame, or sash, then try to go after one of the shingle manufacturers to get a warranty on 10 squ. that they're going to "conditionally" warrant, anyway.


Can you say Eternit Synthetic Slate?

Sorry to go off on this tangent, but a roof vent, is not that big a deal:

especially in SAN DIEGO!






Jaws said:


> I agree, uniform shingles are ideal, but every roof has penetrations.
> 
> In my experience, its all about the proper flashing. Ive seen chimneys without crickets that are 30 years old not leak, with step flashing.
> 
> It is ideal to vent through a gable if accessible, roofs not a problem to me though. Unless its an ascetic problem.



I was making assumptions about proper flashing.

I think the aesthetic problem would be going through the frieze.

Thanks J.


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## wyly (Aug 23, 2011)

MarkJames said:


> Nothing wrong with exhausting at the soffit. Any room to put them side-by-side?


it will eventually rot the sofit.

roof is the only option.

don't even think about venting it in the attic.


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## Creter (Oct 13, 2009)

Hard piped to within a foot of gable vent is acceptable.

(best to do early in the morning this time of the year)

Besides another downside to the soffit vent is in case Aunt Edna is over for a patio party and decides it's time to make a deposit in one of the bathrooms. (Exhaust to the patio making people run for their lives.)


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## MarkJames (Nov 25, 2012)

Let's install a couple skylights and a couple soffit vents for these bathrooms. Next, someone has to wait around to see which one fails first.


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## ArtisanRemod (Dec 25, 2012)

wyly said:


> it will eventually rot the sofit.
> 
> roof is the only option.
> 
> don't even think about venting it in the attic.


Rot the soffit? I better start running dryer vents up through the roof too.


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## wyly (Aug 23, 2011)

ArtisanRemod said:


> Rot the soffit? I better start running dryer vents up through the roof too.


humidity rises if it condenses on the sofit it's just a matter of time before the rot sets in.

I have a bathroom vent running to an outside wall but it's a main floor bath and the sofit is 12ft above it and within code. It just looks ugly stuck in the middle of wall instead of on the roof with all the other vents. The contractor who put it there just took the easy route.


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## wopachop (Feb 12, 2008)

Doing a google search but coming up short. Does anyone make a roof vent designed for 2 bath fans to hook into it? A single vent but with 2 separate outlets? That might work better than using a Y or having to install 2 roof vents.


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## CarpenterSFO (Dec 12, 2012)

ArtisanRemod said:


> Rot the soffit? I better start running dryer vents up through the roof too.


I've seen a dryer vent mess up a car parked in the driveway. Vented right under the engine. Car had been sitting there a while.


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## wyly (Aug 23, 2011)

> Doing a google search but coming up short. Does anyone make a roof vent designed for 2 bath fans to hook into it? A single vent but with 2 separate outlets? That might work better than using a Y or having to install 2 roof vents.


I've not heard of one.

ideally a separate duct for each fan.

two into a Y works fine there are dampers on the fans to prevent one ducting into the other if the vent and blowing air will take the path of least resistance up and out.


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## wyly (Aug 23, 2011)

CarpenterSFO said:


> I've seen a dryer vent mess up a car parked in the driveway. Vented right under the engine. Car had been sitting there a while.


not permissible in the building code here for any vent to be in a carport or even route through a garage, potential CO danger for home.


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## CarpenterSFO (Dec 12, 2012)

wyly said:


> not permissible in the building code here for any vent to be in a carport or even route through a garage, potential CO danger for home.


Was sitting in an open driveway, here in San Francisco, where the weather's almost always cool enough that the vapor condenses right away.


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## wyly (Aug 23, 2011)

CarpenterSFO said:


> Was sitting in an open driveway, here in San Francisco, where the weather's almost always cool enough that the vapor condenses right away.


was that within code or was it a DYI install?


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## CarpenterSFO (Dec 12, 2012)

wyly said:


> was that within code or was it a DYI install?


fftopic:
Inspected, not DIY, and I don't know why it wouldn't have been to code. As far as I can tell, the California Mechanical Code says very little about the termination location, in the case of both moisture and gas exhaust - basically that it needs to be exhausted to the building exterior, and according to manufacturer's instructions. No building openings nearby.

Back to the regular scheduling programming....


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## CO762 (Feb 22, 2010)

Rich D. said:


> I like to vent out a wall. Easiest imo. Like previously stated when vented out a soffit it can collect moisture in the attic.


Would that be much of a problem in san diego?


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## Rich D. (Oct 14, 2011)

Bathroom exaust is humid..

Hot humid air venting by the soffit can find its way into the attic and condense on the roof ply.

It dosnt get cold there everyonce in awhile?


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