Ridge Vent / Gable Vent Help

 
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Old 02-26-2011, 12:00 PM   #1
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Ridge Vent / Gable Vent Help


have a customer who just goyot a ridge vent. Currently have soffits ,gable vents and attic fan. Sshould they cover the gable vents? I would think the gable vents will now disrupt air flow. Home is in north east.
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Old 02-26-2011, 12:17 PM   #2
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Re: Ridge Vent / Gable Vent Help


Leave the gable vents for added ventilation. They won't disrupt the airflow and they are added ventilation if the ridge vent becomes blocked or covered with snow.

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Old 02-26-2011, 12:19 PM   #3
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Re: Ridge Vent / Gable Vent Help


I have looked into this just recently. My thoughts were the same as yours, unfortunately unless someone comes up with something I haven't seen, it appears that the old interrupt the flow of air is not correct.
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Old 02-26-2011, 12:27 PM   #4
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Re: Ridge Vent / Gable Vent Help


Quote:
Originally Posted by enforcer View Post
Sshould they cover the gable vents?
Maybe try doing some research for yourself, and let us know what you found. Here would be a good place to start.
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Old 02-26-2011, 12:48 PM   #5
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Re: Ridge Vent / Gable Vent Help


The ventilation manufacturers and most widely accepted ventilation studies and theories show that the gable vent air flowage would interfere, also know as Short-Circuit the current soffit to ridge ventilation flowage.

It is a recognized short-coming by mold remediation companies that by having competing types of upper air exhaust systems, the probability of mold growth is increased and is recommended to cover up the gable vents when their is a properly functioning soffit intake flowage and ridge vent exhaust flowage already in place.

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Old 02-26-2011, 01:24 PM   #6
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Re: Ridge Vent / Gable Vent Help


Thanks Ed. What about the attic fan?
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Old 02-26-2011, 01:48 PM   #7
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Re: Ridge Vent / Gable Vent Help


I am doing a job next week where the lady has mold. Want to know what it's from? Having ridge-vent and gable vents. When I went in the attic, there were actual piles of snow under the gable vents.

I know Dennis doesn't think that you can short circuit ventilation but my own discoveries and research have proved me otherwise.
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Old 02-26-2011, 02:22 PM   #8
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Re: Ridge Vent / Gable Vent Help


When a Powered Attic Ventilator begins it's cycle, a great volume of CFM will look to be expelled.

Since the Attic Fan location is typically also located near the upper regions of the roof, nearest to the ridge, the Ridge Vents would then be induced into operating as a source of air intake to supply the exhaust fan, following the logic that the air flow will come from not only the nearest source, but also from the one which offers the path of least resistance.

It is not advised.

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Old 02-26-2011, 02:30 PM   #9
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Re: Ridge Vent / Gable Vent Help


Ed,

Quote:
I honestly can not say, that any of the Air Vent videos that I have seen or own, (And Paul Scelsi of Air Vent has graciously allowed me to be privy to videos that are not publicly available), has not shown any with Gable Vents added to the mixture with the smoke tests.

Personally, just in my opinion, I do tend to put more weight in the theory of "Short-Circuiting" the attic ventilation flowage from lower soffit area vents to the roof top exhaust vents when gable vents are introduced to the scenario, but I have not seen conclusive evidence to either support or denounce that theory. Although I have read continual observations from respected Home Inspectors and Contractors that do support the "Short-Circuiting" aspect, those can only be taken at face value without due consideration of knowing all of the other factors that may have been in play at the time.

So, I guess I could have just taken the easier way of making my point by stating, "It Depends".
Quote:
The ventilation manufacturers and most widely accepted ventilation studies and theories show that the gable vent air flowage would interfere, also know as Short-Circuit the current soffit to ridge ventilation flowage.
I take it you have found some new studies??? Care to share?
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Old 02-26-2011, 02:33 PM   #10
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Re: Ridge Vent / Gable Vent Help


Quote:
Originally Posted by Tinstaafl View Post
Maybe try doing some research for yourself, and let us know what you found. Here would be a good place to start.
I\

I have read about all of their articles and there seems to be no real difference, contrary to what Ed and I have been lead to believe.

That is why I was wondering if anyone has another source on this.
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Old 02-26-2011, 02:51 PM   #11
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Re: Ridge Vent / Gable Vent Help


Quote:
What about the attic fan?
Spend some time looking for a study/information on this question.

Here is some info I put together;

http://www.roofingcontractorreview.c...ttic-fans.html
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Old 02-26-2011, 03:34 PM   #12
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Re: Ridge Vent / Gable Vent Help


BamBamm,

I recently finished this roof. This winter snow blew into this dormer vent that was installed by the carpenters. Enough snow got in to cause a leak in the ceiling.

Do I blame the ridge vent for causing a short circuit?
No, because there is no ridge vent.

I blame the poorly designed dormer vent.

You might want to look into other causes for your customers mold such as insulation and air sealing issues.

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Old 02-26-2011, 08:15 PM   #13
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Re: Ridge Vent / Gable Vent Help


i remember seeing a model of a house with ridge and gable vents and smoke was introduced showing the gable vents were not competing with the ridge vent

was that yours Dennis?
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Old 02-27-2011, 07:43 AM   #14
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Re: Ridge Vent / Gable Vent Help


Hi Tom,

That was probably mine. Was it of low quality and budget and looked like it was filmed in a basement?

I don't think there are any other sites or sources of information relating to the issue. That's why I made the video. The short circuit concept didn't make sense to me.
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Old 02-27-2011, 08:04 AM   #15
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Re: Ridge Vent / Gable Vent Help


i thought it was pretty good
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Old 02-27-2011, 08:25 AM   #16
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Re: Ridge Vent / Gable Vent Help


What?

No link?

I'd like to see that vid Dennis....

Nice site BTW
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Old 02-27-2011, 11:52 AM   #17
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Re: Ridge Vent / Gable Vent Help


if the customer currently has gable vents, i would close them up if a ridge vent is installed. of course you would want to make sure there is enough intake from the soffits. installing ridge vent and then leaving the gable vents will interrupt the natural convection from the ridge. thats how it was explained to me and it does make sense. picture a vacuum and then putting a hole in the hose.
as far as an attic fan,i am not entirely sure about that. need to delve into it more.
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Old 02-27-2011, 04:57 PM   #18
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Re: Ridge Vent / Gable Vent Help


Thanks

Here's the link;http://www.roofingcontractorreview.c...cuit-myth.html

There are a couple others on the site that pretty much illustrate the idea but with a hip style roof.
http://www.roofingcontractorreview.c...f-venting.html

http://www.roofingcontractorreview.c...ttic-fans.html
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Old 02-27-2011, 05:09 PM   #19
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Re: Ridge Vent / Gable Vent Help


thanks Den thats the one

when things start to make sence to me thats when i worrymost of the things ''i was told''or ''figured out for myself''turns out not to be....why is that?
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Old 02-27-2011, 07:12 PM   #20
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Re: Ridge Vent / Gable Vent Help


Interesting videos Dennis,
Makes me wonder too about closing
gable end vents when ridge vents are installed.
I always wanted to do a similar experiment when
this argument first came up but figured that actual,
real life conditions would be hard to duplicate and
control.

One condition would be actual varying outside humidity
and temperature conditions in comparison to interior
attic humidity and the varying densities of heated
air
as it left the conditioned areas of the house.

Since any moisture laden warmer air leaving
the conditioned area of the house may be heavier
than outside air,I can't help but think that there
may still be a possibility to have a short circuit
by leaving in the gable end vents.
I like the demo but feel it has to be taken a couple
steps further to really prove this point.
Burning incense is just dry heated smoke which
I don't think can be a substitute for actual attic
conditions.

Just saying............

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