"yourname" wrote in message news:0R8ff.68$N44.6@trndny08...
Chas Hurst wrote:
"yourname" wrote in message
news:2l7ff.13164$Rb.2712@trndny04...

I have a hard time believing that in actual practice, this

is really an issue. It's done on most of the homes here in NJ that
I've seen and hasn't been harmful.


I've got the fan vented thru the soffit. In cold weather the vented air
condenses quickly making it visible. It's quite obvious that it blows

away

from the house and does not get sucked back into the adjoining vent.




Ya know, last year I put two vents in through the roof. They don't cost
much, don't take long and don't leak. It's just a bad ida to vent them
in the attic period


So you put 2 holes in your roof and I didn't. Furthermore I vented out
thru
the soffit not in the attic. I hope your holes in the roof turn out
better
than your reading comprehension.


And thus my house is up to code and yours isn't. there is no difference
between a vented soffit and the attic. I am happy that your insulation
isn't soaking wet, but you won't be working on my house anytime soon.
Hey, the gas furnace usually vents away from the house too, but you don't
put it right next to the window.

Since I merely pointed out that it was not a big deal to put it through
the roof, the same way that the soil stack does for the very same
bathroom, an is not prone to leaks, I think it is your reading
comprehension that is questionable.

You keep talking about "the code". Please tell us where you live (not the
street address) so we can look up your states building code on line. If
there is a restriction from venting a bath fan into the outside air through
a dedicated hole in the soffit I would really like to see it.

I would want to see "the code" that says this.
I think a lot of people are confusing the hack job of pointing the end of
the ducting into a vented soffit, with the proper installation which is to
run the duct out *through* the soffit terminating with a grill or louvered
vent cap.

"gary" wrote in message
news:u7bff.528245$tl2.166178@pd7tw3no...
That is not done here and I believe it is against code. The moisture in
the winter builds up ice and causes problems in the soffit and with any
wood in there.


wrote in message
oups.com...
" Through the sidewall or the roof. A poor third would be through the
soffit, which may not be code locally. "

I don't know where venting a bathroom fan out the soffit is a code
violation? Here in NJ most homes are done that way and we are about as
regulated as it gets. I don't see anything wrong with doing a soffit
vent.

" I would want to see "the code" that says this.
I think a lot of people are confusing the hack job of pointing the end
of
the ducting into a vented soffit, with the proper installation which is
to
run the duct out *through* the soffit terminating with a grill or
louvered
vent cap. "

I agree!

wrote:
" I would want to see "the code" that says this.
I think a lot of people are confusing the hack job of pointing the end
of
the ducting into a vented soffit, with the proper installation which is
to
run the duct out *through* the soffit terminating with a grill or
louvered
vent cap. "

I agree!

i have a 1962 built ranch in cols ohio. the above is what i did when
i replaced a bath fan. put the metal pipe about 1/2" or more past the
original wood soffit. it has vinyl soffit over that. i then used the
vent soffit over the pipe. next vent opening 2 to 3 feet away. my only
question is when i did this the old fan had no vented piping at all.
just emptied into the attic. there was no damage over the last 30 plus
years. so if the attic has good ventilation you may not have to worry
which way you go depending on you climate?

I used 6" flex duct myself for a fan that I recently put it.
(I used the insulated stuff too)

I vented it to the soffit and put on a auto opening
grill to vent the bathroom air to the outside.

Nothing like having a 200 cfm van venting the bathroom.
No more smells, no fogging the mirrors nothing.
Just sucks the hell out of the heat in the house

Didnt want to go with a through room install. My feelings
are the less holes in my roof, the better off I am.

Tom

According to :
"I seem to recall, either in Fine Homebuilding or a CMHC publication
that
under certain circumstances in cold climates venting up through the
roof
can lead to thermosyphoning hot air continuously when the fan is off.
"

Veeery interesting! I had never thought about that. I suspected a
similar and worse effect occurs when people run a bath vent to the
underside of a roof mounted fan. When the roof fan runs in summer, it
will suck cool airconditioned air from the bathroom, even if the
bathroom fan is off. I would think as you pointed out, that just
having a straight up run from the bathroom to a regular roof vent would
provide and ideal path for convection.

As I mention, that's merely wasteful... It gets vastly worse if you
have condensation dripping into the room.

I don't know whether putting a "trap" (S curve) into the vent (as
others have mentioned) will be sufficient to break the thermosyphon.
I would suspect not in most cases, but, at least it should prevent
condensation draining _through_ the fan... But, the "trap"
might get rather yucky after a few years.

Yeah, running the bathroom vent to the underside of a roof mounted fan would
be bad even in the summer too if you had AC.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

This may be a little OT, but if a person was dead set for some reason
on venting to the attic OR they came across such a set-up, you can
simply change your habits to minimize risk of attic condensation.

For instance, don't run your fan when it gets chilly enough outside to
see your breath (or thereabouts). In cold weather, heated interiors
experience a drop in humidity and can absorb lots of moisture without
the humidity getting high. It may be a good idea to run your
forced-air furnace and keep the bathroom door cracked when you take a
shower to keep an influx of low-humidity air into the bathroom. In the
winter, I can take a shower without running the vent fan and the
mirrors don't even begin to "steam up".

wrote:
I used 6" flex duct myself for a fan that I recently put it.
(I used the insulated stuff too)

I vented it to the soffit and put on a auto opening
grill to vent the bathroom air to the outside.

Nothing like having a 200 cfm van venting the bathroom.
No more smells, no fogging the mirrors nothing.
Just sucks the hell out of the heat in the house

Didnt want to go with a through room install. My feelings
are the less holes in my roof, the better off I am.

Tom




Yes, I did the same thing. Insulated flex duct out to the
soffit. Very nice setup.

TP

MOLD! Homes that have poor venting that just vent into the attic
eventually grow MOLD. MOLD is unhealthy! People don't buy moldy
houses!

I've had my best friend walk away from 3 houses because the inspections
found mold in the attic due to poor ventilation. 1 house was bulldozed
after inspections found it was uninhabitable.

ALWAYS vent to the outside air. It may cost a bit, but well worth it
if your house is your nest egg. Nothing worse than seeing your nest
egg bulldozed because of toxic mold.

MOLD! PEOPLE PLEASE DO YOUR RESEARCH!
New Jersey has some of the worse mold cases/stories because old
contractors and do-it-yourselfers vented into the attic and not to the
outdoors!
Home inspections now often include mold inspections when the house is
older; my friend has walked away from 3 homes in New Jersey because all
had toxic levels of mold. 1 house was bulldozed recently because it
was unihabitable due to mold. Nice home, wasn't trashy BUT THE OWNER
VENTED THE BATH INTO THE ATTIC FOR 15 YEARS!

Good the picture came through.


"gary" wrote in message
news:Wkmff.527398$1i.336885@pd7tw2no...
New bathroom fan install with "trap"

"gary" wrote in message
news:j6bff.524440$1i.262605@pd7tw2no...
That is done on all new buildings here. I just took a picture of one
today.
Can I upload binaries here? Do you really think a slight U in a 4" pipe
is
going to fill up with water from the minimal amount of snow or rain that
might get into the pipe? If you get that much water in there the trap is
NOT your problem. You have other problems. If you do not put the
"trap"
there where do you think that water goes. Right into your fan, your
motor
and your grill (if metal) and causes rust.


"Dennis" wrote in message
newsP9ff.22603$5R4.2331@trnddc06...
Your kidding right? Trap the duct?

"gary" wrote in message
newslRef.522479$tl2.34263@pd7tw3no...
Use insulate flex ducting to prevent moisture condensation and put a U
in
it so that any water that might get in the pipe through the top of the
vent does not drain back into your fan.

Gary, I just can't agree. There should be no water or snow infiltration in a
properly designed termination. (It has a damper in the exterior cap to
prevent just that.)

By adding unnecessary twists and turns, you are adding some back pressure
for the blower to overcome, which would degrade its performance (to whatever
extent would depend on the specific system.) Also adding a trap could
possibly cause some moisture in the air stream to condense prior to being
evacuated (this would especially true if your roof cap has no damper and
allows rail to enter). This would be undesirable as standing water could
deteriorate the vinyl ducting over time. (I prefer metal ducting as the high
heat in an attic can cause plastics to deteriorate over time).

In any case, a duct that runs as straight as possible is the most desirable
way to vent, and millions of homes exist with roof terminations where this
presents no problems at all.

"gary" wrote in message
news:j6bff.524440$1i.262605@pd7tw2no...
That is done on all new buildings here. I just took a picture of one
today. Can I upload binaries here? Do you really think a slight U in a 4"
pipe is going to fill up with water from the minimal amount of snow or
rain that might get into the pipe? If you get that much water in there
the trap is NOT your problem. You have other problems. If you do not
put the "trap" there where do you think that water goes. Right into your
fan, your motor and your grill (if metal) and causes rust.


"Dennis" wrote in message
newsP9ff.22603$5R4.2331@trnddc06...
Your kidding right? Trap the duct?

"gary" wrote in message
newslRef.522479$tl2.34263@pd7tw3no...
Use insulate flex ducting to prevent moisture condensation and put a U
in it so that any water that might get in the pipe through the top of
the vent does not drain back into your fan.

Unlikely. You would actually have to chance the laws of thermodynamics to
make a difference. One area you might not be considering is that it's not
only against code, it's also more expensive to heat the home. Bath (and
kitchen) fans carry a tremendous amount of moisture. Dump this into the
attic in cool/cold weather will cause this moisture to settle into the
insulation; degrading the performance and moving the dew point closer to the
heated side. It's not out-of-the question to consider a R-value loss of 50%
or more (one test showed much more) on cold days.

This may be a little OT, but if a person was dead set for some reason
on venting to the attic OR they came across such a set-up, you can
simply change your habits to minimize risk of attic condensation.

"Dennis" wrote in message
news:ZbNgf.2937$F%3.2805@trnddc05...
Gary, I just can't agree. There should be no water or snow infiltration in
a properly designed termination. (It has a damper in the exterior cap to
prevent just that.)

By adding unnecessary twists and turns, you are adding some back pressure
for the blower to overcome, which would degrade its performance (to
whatever extent would depend on the specific system.) Also adding a trap
could possibly cause some moisture in the air stream to condense prior to
being evacuated (this would especially true if your roof cap has no damper
and allows rail to enter). This would be undesirable as standing water
could deteriorate the vinyl ducting over time. (I prefer metal ducting as
the high heat in an attic can cause plastics to deteriorate over time).

In any case, a duct that runs as straight as possible is the most
desirable way to vent, and millions of homes exist with roof terminations
where this presents no problems at all.

"gary" wrote in message
news:j6bff.524440$1i.262605@pd7tw2no...
That is done on all new buildings here. I just took a picture of one
today. Can I upload binaries here? Do you really think a slight U in a
4" pipe is going to fill up with water from the minimal amount of snow or
rain that might get into the pipe? If you get that much water in there
the trap is NOT your problem. You have other problems. If you do not
put the "trap" there where do you think that water goes. Right into your
fan, your motor and your grill (if metal) and causes rust.


"Dennis" wrote in message
newsP9ff.22603$5R4.2331@trnddc06...
Your kidding right? Trap the duct?

"gary" wrote in message
newslRef.522479$tl2.34263@pd7tw3no...
Use insulate flex ducting to prevent moisture condensation and put a U
in it so that any water that might get in the pipe through the top of
the vent does not drain back into your fan.








The OP isnt showing, so....

The proper way to run a bathroom vent is simple, and to do it by code is
simpler yet..

If the run is over 14 Feet, it needs to be metal snap lock pipe. Period.
If water is getting into a vent pipe that feeds to the roof, the wrong cover
is on it.
If condensation is an issue, then you have the pipe obviously not ran in the
best location and it should be relocated if possible, and again, if over 14
feet, metal ducting used, and if needed, insulate with proper duct wrap.
Condensation, can also occur when you are using a fan with too low of a CFM
for the space, or, trying, as others have said to make it harder than it
needs to be, and installing a bunch of so called traps (that are not to code
here anyway) and raising the static pressure of a tiny POS fan..unless you
are using Panasonics.

Dennis wrote:
Unlikely. You would actually have to chance the laws of thermodynamics to
make a difference. One area you might not be considering is that it's not
only against code, it's also more expensive to heat the home. Bath (and
kitchen) fans carry a tremendous amount of moisture. Dump this into the
attic in cool/cold weather will cause this moisture to settle into the
insulation; degrading the performance and moving the dew point closer to the
heated side. It's not out-of-the question to consider a R-value loss of 50%
or more (one test showed much more) on cold days.

This may be a little OT, but if a person was dead set for some reason
on venting to the attic OR they came across such a set-up, you can
simply change your habits to minimize risk of attic condensation.

You entirely missed what I wrote. The whole idea is NOT to dump
moisture into the attic by NOT running the fan during cool outside
conditions.

Hi Dennis, did you see the picture I posted. That is how all the new
buildings have their bathroom fans installed now.


"Dennis" wrote in message
news:ZbNgf.2937$F%3.2805@trnddc05...
Gary, I just can't agree. There should be no water or snow infiltration in
a properly designed termination. (It has a damper in the exterior cap to
prevent just that.)

By adding unnecessary twists and turns, you are adding some back pressure
for the blower to overcome, which would degrade its performance (to
whatever extent would depend on the specific system.) Also adding a trap
could possibly cause some moisture in the air stream to condense prior to
being evacuated (this would especially true if your roof cap has no damper
and allows rail to enter). This would be undesirable as standing water
could deteriorate the vinyl ducting over time. (I prefer metal ducting as
the high heat in an attic can cause plastics to deteriorate over time).

In any case, a duct that runs as straight as possible is the most
desirable way to vent, and millions of homes exist with roof terminations
where this presents no problems at all.

"gary" wrote in message
news:j6bff.524440$1i.262605@pd7tw2no...
That is done on all new buildings here. I just took a picture of one
today. Can I upload binaries here? Do you really think a slight U in a
4" pipe is going to fill up with water from the minimal amount of snow or
rain that might get into the pipe? If you get that much water in there
the trap is NOT your problem. You have other problems. If you do not
put the "trap" there where do you think that water goes. Right into your
fan, your motor and your grill (if metal) and causes rust.


"Dennis" wrote in message
newsP9ff.22603$5R4.2331@trnddc06...
Your kidding right? Trap the duct?

"gary" wrote in message
newslRef.522479$tl2.34263@pd7tw3no...
Use insulate flex ducting to prevent moisture condensation and put a U
in it so that any water that might get in the pipe through the top of
the vent does not drain back into your fan.

only against code, it's also more expensive to heat the home. Bath (and
kitchen) fans carry a tremendous amount of moisture. Dump this into the
attic in cool/cold weather will cause this moisture to settle into the

It occurs to me that this isn't necessarily true of half-baths,
though.

Your right, I didn't get that from what you originally wrote. But that
defeats the whole purpose of ventilation, doesn't it? The purpose it to
ensure use year round. But I have to admit, you are correct. If you don't
use the fan, not much moisture will get trapped in the attic.

You entirely missed what I wrote. The whole idea is NOT to dump
moisture into the attic by NOT running the fan during cool outside
conditions.

I think the AHJ needs to talk with that builder. It's not to code that I'm
aware of. (But hey, I've seen worse...)
Have a great Thanksgiving.
Dennis

"gary" wrote in message
news:TpRgf.571676$oW2.418298@pd7tw1no...
Hi Dennis, did you see the picture I posted. That is how all the new
buildings have their bathroom fans installed now.

I've never looked at the Panasonics. You like them?

here anyway) and raising the static pressure of a tiny POS fan..unless you
are using Panasonics.

Less to be certain. But just the air by itself carries a lot more water
vapor than can dissipate in cold air, and a fan will draw air from outside
the half-bath. It still will be moisture-laden air and that moisture will
collect on the insulation. Not as much or as fast, but it will affect the R
value to some extent. Best it goes outside in the winter (whenever
possible).


"Goedjn" wrote in message
...

only against code, it's also more expensive to heat the home. Bath (and
kitchen) fans carry a tremendous amount of moisture. Dump this into the
attic in cool/cold weather will cause this moisture to settle into the

It occurs to me that this isn't necessarily true of half-baths,
though.

"Dennis" wrote in message
news:9s7hf.1263$R42.743@trnddc01...
I've never looked at the Panasonics. You like them?

here anyway) and raising the static pressure of a tiny POS fan..unless
you are using Panasonics.



They cost a bit more, but you cant hear them run, you cant beat them for
what they do, and they aint too shabby looking either.

The best

"CBHVAC" wrote in message
...

"Dennis" wrote in message
news:9s7hf.1263$R42.743@trnddc01...
I've never looked at the Panasonics. You like them?

here anyway) and raising the static pressure of a tiny POS fan..unless
you are using Panasonics.



They cost a bit more, but you cant hear them run, you cant beat them for
what they do, and they aint too shabby looking either.