On 11 Nov 2004 16:49:42 GMT, email@example.com (Joe Bobst) wrote:
Bingo! I decided years ago that if there is enough air movement (wind
or temperature difference) to spin a turbine, there is enough for
ridge or gable vents to do the job.
I'm in Texas with ridge vents.
I suggest you look at the Building Science Corporation web site.
It provides climate specific researched information.
Attic venting in hot humid climates is not always a good idea.
As for turbines, I agree with the position that they do no more than a
hole in the roof.
Phone number for a roofing materials pro is 1-800-ROOFING.
That's the number for Owens-Corning. And their warantee says
that if you don't have at least 1 square foot of venting for every
300 square feet of vented space, you have no shingles warantee.
Better to have twice that much, it's the minimum.
Even a 12" turbine is not even a square foot. Only 113 square
inches, a square foot is 144.
I say go with ridge vents suited to heavy winds with plenty of
Ask the folks at Owens -Corning. You might even consider
a roof-edge vent, too. Functions like a drip edge, gives more
'soffit venting'. Certainteed also has one.
And ignore the knuckle-draggers that base what you should do
on what others in the neighborhood have done. After all, I seen
people put garbage bags over their turbines for the wintertime.
Either to stop them from spinning and the noise being troublesome,
or to trap all that nice warm moist air in the attic. What idiots.
It's an easy decision: use both.
Turbines exchange the attic air based (mostly) on wind velocity - ridge
vents exchange attic air based on the heat in the attic being greater than
the outside air. They work differently.
Turbines don't work very well when there's no wind, so the ridge vents will
provide some relief. With a modest wind, the turbines will way out-perform
the ridge vents.
I've got FOUR humongous turbines and about 30' of ridge venting on a 3000'
That said, you can't have too many soffit vents. Use this construction
period to double whatever you've got.
Ridge vents work good down here in the south on hot summer days, as long as
good matching and continous sofet venting is used to ensure that each are
between the rafters have air flow and that there are no blockages.
When the sun heats up the roof on my house, you can feel the gust of air
moving between the rafters up and out the ridge vents.
The house orignally did not have ridge venting. After installed the attic
seems no to get as hot and the last shigles on the roof are lasting much
longer without getting baked as before.
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