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wrote:
Natual air flow??? What kind of air flow do you think you have
coming from the soffits to the roof line? Wind tunner perhaps? Not.

Soffit vents are generally (I am saying generally from the ones I have
seen) are a few feet apart. They are suppose to help with heat
escaping
in the summer and keeping the roof cold in the winter so water doesnt
prematurely melt and create an ice backup. (ice dam)

Correct. They help because the cooler heavier air come IN through the
soffit vents and the hot (lighter) air exits from the higher roof or gable
end vents. The natural air flow is UP.

That being said, putting a 6" hole in the soffit isnt going to disrupt
anything.
The forced air from the fan will blow the exhaust right out the vent.
More
or less a few feet away. The 'Natural Flow" of the soffit doesnt even
come close to making a measureable vacume effect that would suck in
the exhaust from the vent in the soffit.

All the air that does go through the system is "sucked" up through the
soffit vents. Where else do you think it is going to come from???

One thing that can also bit people in the butt is that when venting
moist
warm air vertically, you increase the chance of condensation flowing
back
in from the vent. Lots of insulation would be advisable. (not sure
if your in
a warm climate or cold)

That I can generally agree with.

Horizon. runs you can pitch so that the flow wont come back.

Of course you do need to provide somewhere for it to go. :-)

Just a thought...

Tom

P.S.... I personally HATE putting holes in the room. More holes,
more chance of
water coming in. Over the years, the moisture from the showers and
rust
from the vent cause some crappy looking roofs too (stains)

Good vents don't rust, but too much moisture does a great deal of damage
to homes.

--
Joseph Meehan

Dia's Muire duit