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Been hearing lately that ridge venting is unnecessary and considered over-venting, unless you live in a really cold climate. Out here they are saying ridge venting is necessary in the mountains only. Any body agree with that? I never knew there was such a thing as over-venting. I was under the impression that the best roofing job would include soffit vents combined with a ridge vent.
 

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My father, a 30 year roofing pro only recomends it on roofs 8/12 and steeper. He was called to a massive sq 4/12 complex some years ago that had ridge vent and was having some leaking problems. When he crawled in the attic area he noticed 3-4 foot snow drifts in some areas! He was payed to remove the ridge vent and instal some 150 air vents. There are so many various brand though it's tough to know which ones are good and which ones are junk.
 

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I disliek placing it on anything less than 4/12. Ridge vent ONLY works with equal or greater intake. If you have no intake DONT USE ridge vent, use something else.

From the seminars I have attended sponsored by the ventilation manufacturers,a nd from everything I have ever read: there is no such thing as over ventilating (unless you are mixing ventilation systems). A good balance of intake, exhaust and insulation is essential. The insulation has nothign to do with the ventilation except keeping your energy bills down and it does actually help keep humidity out of the attic to a degree.

www.airvent.com has the cadillac of ridge vents. We usually use www.rollvent.com unless requested to use the "baffled" ridge vent.

Even some roofers I have spoken with don't understand how a ridge vent works. Air Vent has periodic seminars I encourage anyone who works with sloped roofing to attend. I thought I knew ventilation until I started attending these seminars and speaking with the engineers who design the products. Definite eye opener.
 

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I agree w/Grumpy....you can't overventillate a roof. IRC & UBC require venting ratio of minimum 1:300. More is better.
Jim
 

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Rare indeed would be the overventilated house. The wind can create a suction as it passes over the ridge vent. If there is adequate intake at the soffit, this is a good thing as it pulls the air from down low. If there is not enough intake, the suction will pull air from somewhere. This could be from the conditioned space if it isn't tight (that's come expen$ive air) or even from another section of the ridge vent.
I recently was called upon to examine a 3 year old fiberglass 3-tab roof that was showing a lot of curling. The ridge was 100% vented, there were gable vents, but 0 soffit vents. This was creating a ventilation short circuit. There was lots of airflow at the top, but virtually nil down low. Where do you suppose the curling was the worst? Down low.
 

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Specialist, that's exactly what I said... You need equal or greater soffit ventilation when a ridge vent has been installed and don't mix ventilation systems. A ridge vent simply won't work unless installed properly, and who could expect it to? Not much of anything will work properly when installed improperly!
 

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Mike, the new thing here is called 'controlled attic space'. In essence the attic space is entirely sealed with a sprayed polyurethane foam. Maybe this is what you are hearing about.
 

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Specialist, that's exactly what I said... You need equal or greater soffit ventilation when a ridge vent has been installed and don't mix ventilation systems. A ridge vent simply won't work unless installed properly, and who could expect it to? Not much of anything will work properly when installed improperly!
What do you guys think of power vents? Many people seem to believe in them...I don't.
 
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