# attic venting - ridge vent with soffit inlet AND gable vent



## raycyrx (Jun 1, 2014)

I recently had my entire exterior redone.  Started with the roof and had a ridge vent installed with the redo.  New soffits were then done with 100% vented pieces (the nice hidden vents in the groove). 

When the siders did their part, they were supposed to install DECORATIVE vents on each of my three gables, but instead put in functional vents.  

My question is, will the ridge vent with soffit intake still do their job properly WITH the functional gable vents or should I cover up the gable vents from the inside?


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## oldognewtrick (Jun 1, 2014)

Take some plastic and close off the gable vents. You will short cycle the air circulation. 

And  to House Repair Talk!


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## Wuzzat? (Jun 1, 2014)

Or you may want to block off the gable vents all year, or part of the year, for other reasons.  At least now you have the option.


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## nealtw (Jun 1, 2014)

Close the gable vents.


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## Wuzzat? (Jun 2, 2014)

This seemed to me controversial and usually that means everyone is right at least some of the time no matter what their position on this.

I couldn't find a building science pdf link on this and running experiments with thermometers and looking up Cooling Degree Days is burdensome.

Oh, well. . .


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## nealtw (Jun 2, 2014)

Wuzzat? said:


> This seemed to me controversial and usually that means everyone is right at least some of the time no matter what their position on this.
> 
> I couldn't find a building science pdf link on this and running experiments with thermometers and looking up Cooling Degree Days is burdensome.
> 
> Oh, well. . .



You don't need code to figure it out. The idea is to cool the roof as much as posible, winter and summer. As warm air leaves at the ridge it suck air in the soffets causing air flow under the whole roof. Dewpending on the wind the gable vent will introduce air instead of using soffet air or soffet air will leave by the gable vent leaving the ridge hot. So no gable vent unless there is no other choice.


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## Wuzzat? (Jun 2, 2014)

nealtw said:


> You don't need code to figure it out. The idea is to cool the roof as much as posible, winter and summer. As warm air leaves at the ridge it suck air in the soffets causing air flow under the whole roof. Dewpending on the wind the gable vent will introduce air instead of using soffet air or soffet air will leave by the gable vent leaving the ridge hot. So no gable vent unless there is no other choice.


Why doesn't the gable air cool the ridge?  
I'd think as long as the air is moving, outside air is cooling the entire attic volume by some route and the Stack Effect mostly assures all the air is moving upward.

All of this ASHRAE stuff is complex, it's worse than other types of engineering, although civil engineering does also depend somewhat on climate.


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## nealtw (Jun 2, 2014)

http://homeenergypros.lbl.gov/forum/topics/the-short-circuit-theory-keep-or-remove-those-gable-vents

This one agrees with you all the way to the end when they make one mention about wind. My question is who lives where there is no wind.


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## Wuzzat? (Jun 2, 2014)

I saw that one early on and then saw the NACHI people heatedly arguing, so that's when I decided it's controversial. 

Usually, asking for specifics for each option, dollars saved or comfort gained or shingle lifetime extended, makes most people pick up their marbles and go home.

When all else fails and the issue is important, read
http://www.amazon.com/dp/1400065666/?tag=skimlinks_replacement-20

This book says 'extraordinary claims require extraordinary proof' but the claim of either side is not extraordinary.  

I have gable vents, no soffits & no ridge, and for a long time I had an attic fan which finally failed, and then some people said the cost of elec. to run the fan is more than the savings.

???


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## nealtw (Jun 2, 2014)

As with anything else,as long as someone is making nice looking gable vents, they will be adding to the confussion

http://www.airvent.com/professional/resources/troubleshooting.shtml


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## oldognewtrick (Jun 3, 2014)

I still say close them, why? Because that's what the manufactures say to do. Not following the shingle MFG's installation specs will void their warranty.


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## Wuzzat? (Jun 3, 2014)

nealtw said:


> As with anything else,as long as someone is making nice looking gable vents, they will be adding to the confussion
> 
> http://www.airvent.com/professional/resources/troubleshooting.shtml


Your link hints at laminar flow, with the wind from gable vents maybe causing turbulent flow, and laminar is better for heat transfer.
This gets interesting.

http://www.google.com/search?client...=gable+ridge+soffit+"laminar+flow"+pdf&rls=en


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## Wuzzat? (Jun 3, 2014)

oldognewtrick said:


> I still say close them, why? Because that's what the manufactures say to do. Not following the shingle MFG's installation specs will void their warranty.


Now that you mention it, "Does it void the warranty?" should be the first question asked and the answer should pull more weight than many Internet searches.


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## oldognewtrick (Jun 3, 2014)

No shingle MFG will warranty their product over an unapproved method of ventilation. Certainteed, will warranty their shingles over a non-ventilated, insulated roof deck, but require proper venting on ventilated roof structures. GAF and the others do not warranty over insulated/spray foam surfaces.

In the installation manuals they will specify to close off the gable or dormer vents.


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## nealtw (Jun 3, 2014)

I am sure the MFGs have their reason and mostly money. Like I said before, just because there is a debate dosn't make both sides right. There lots of people selling nice looking vents for the gable, ask them to warranty the roof. It is all about the money like big oil and GW.


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## oldognewtrick (Jun 3, 2014)

Ventilation has been a moving target the last 20 years. There are as many opinions as well, you name it. Only thing I can tell you is, what works on one house usually doesn't preform well on the next door neighbor. There are so many factors that figure into the equation that I got to the point that the MFG has the ultimate say, cause they are the one taking care of product failure if it occurs. If I as an installer deviate from their requirements, I put my customer in a bad position, cause I didn't do what they hired me to do. 

Guess I'm getting to old to reinvent the wheel.


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## nealtw (Jun 3, 2014)

The wheel has been around for a while, there are people who tell they make a better one.


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## oldognewtrick (Jun 3, 2014)

nealtw said:


> The wheel has been around for a while, there are people who tell they make a better one.




I'm on my second set of Toyo'S on my F-350 that will hit 60K.


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## nealtw (Jun 3, 2014)

You are just not keeping up


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## inspectorD (Jun 4, 2014)

oldognewtrick said:


> I'm on my second set of Toyo'S on my F-350 that will hit 60K. View attachment 6627



Wow...I would love to get that kind of wear on my 6 tires.....


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## inspectorD (Jun 4, 2014)

As for the Attic venting, Oldog is right on. Every home is different. follow what the Manufacturer wants, or no warrantee. Pretty simple actually.


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## Wuzzat? (Jun 4, 2014)

nealtw said:


> ask them to warranty the roof.


In other words, they should put their money where their mouth is.


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