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Too soon old,
Too late smart
posted
We have a 3 story house with a hip roof. The builder put a ridge vent in along with adequate soffit vents. Also have an exhaust fan.

We're now in the process of getting estimates for a new roof. Both roofers that came for estimates recommended that the ridge vent be closed off. They said the soffit vents and ridge vent counteract each other.

I know people have differing opinions on attic ventilation, usually about the pros & cons of an exhaust fan.

But I'm reluctant to seal off the ridge vent. What say the forum?


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I wouldn't let anyone do to me what I've done to myself
 
Posts: 1487 | Location: NoVa | Registered: March 14, 2009Reply With QuoteReport This Post
Nullus Anxietas
Picture of ensigmatic
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quote:
Originally posted by RogB:
We have a 3 story house with a hip roof. The builder put a ridge vent in along with adequate soffit vents. Also have an exhaust fan.

We're now in the process of getting estimates for a new roof. Both roofers that came for estimates recommended that the ridge vent be closed off. They said the soffit vents and ridge vent counteract each other.

Wow

If we're getting our terminology straight: DO NOT use either of those roofers, because they don't know WTF they're talking about.

First let's make certain we've got our terms right. A soffit is where the roof extends beyond the walls, creating an overhang. Like this:



Both soffit vents and either cans or ridge/hip vents are absolutely necessary to ensure adequate airflow through the attic space. In fact: The amount of soffit vents and roof vents (whether cans or ridge/hip) are supposed to be balanced.

When we had our roof re-roofed three years ago or so, they went to a great deal of effort to make certain all the soffit vents were clear, removed all the cans, and put in ridge and hip vents.

Our roof has a 50-year, unconditional, one-time-transferable replacement warranty backed by Dow Corning.

With adequate soffit and ridge/hip ventilation, the powered exhaust fan is probably not only unnecessary, but may even be counter-productive. Is it perhaps that to which they were referring?



"America is at that awkward stage. It's too late to work within the system,,,, but too early to shoot the bastards." -- Claire Wolfe
"If we let things terrify us, life will not be worth living." -- Seneca the Younger, Roman Stoic philosopher
 
Posts: 26009 | Location: S.E. Michigan | Registered: January 06, 2008Reply With QuoteReport This Post
Ammoholic
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Everything ensigmatic said.



Jesse

Sic Semper Tyrannis
 
Posts: 20758 | Location: Loudoun County, Virginia | Registered: December 27, 2014Reply With QuoteReport This Post
Fighting the good fight
Picture of RogueJSK
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I'd like to piggyback a related question:

Are there noticeable advantages to ridge vents over traditional box vents? Or are they about same, provided there's an appropriate level of attic ventilation overall?


We may be getting a new roof, and one of the roofers suggested "upgrading" to ridge vents if there's enough money left. Our house currently has about a dozen roof vents that look similar to this:




(We're not to the point in the process where I've had an in-depth discussion with a roofer about replacing the vents, but I'd like to have a bit of background info going into it.)
 
Posts: 32430 | Location: Northwest Arkansas | Registered: January 06, 2008Reply With QuoteReport This Post
quarter MOA visionary
Picture of smschulz
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quote:
Originally posted by Skins2881:
Everything ensigmatic said.


Agreed!


DO NOT get rid of ridge vents!
 
Posts: 22858 | Location: Houston, TX | Registered: June 11, 2006Reply With QuoteReport This Post
Too soon old,
Too late smart
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Keeping the ridge vent and disconnecting the exhaust fan sounds like the right course of action.

Thanks for the help! Have another estimate this week, will be interesting to see what they say.


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I wouldn't let anyone do to me what I've done to myself
 
Posts: 1487 | Location: NoVa | Registered: March 14, 2009Reply With QuoteReport This Post
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OP, you said "The builder put a ridge vent in along with adequate soffit vents. Also have an exhaust fan."

Then said "Both roofers that came for estimates recommended that the ridge vent be closed off. They said the soffit vents and ridge vent counteract each other."

Are you sure they didn't say the Ridge and exhaust fans counteract each other?

If so, this is true. You want soffit vents and then one of 3 options. 1. A Ridge vent, 2. Can vents, 3. Gable vents passive or powered.

If you're running a combination your ruining the natural convective cooling.




 
Posts: 1514 | Location: Ypsilanti, MI | Registered: August 03, 2006Reply With QuoteReport This Post
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quote:
Originally posted by RogB:
Keeping the ridge vent and disconnecting the exhaust fan sounds like the right course of action.

Thanks for the help! Have another estimate this week, will be interesting to see what they say.


I think this is the right course of action. You're paying for electricity to run the exhaust that is also hurting your convection flow.




 
Posts: 1514 | Location: Ypsilanti, MI | Registered: August 03, 2006Reply With QuoteReport This Post
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The ridge and soffit vents combined make a complete system for even flow. Adding a fan changes things a bit...

The source of those guys opinion originate from this theory...
When powered vent fans are installed the closest vents are closed off to prevent ventilating just the local area around the fan. That is the basis for the suggestions you got. The fan will suck from the ridge vent and not properly pull from the soffit vents further away. (Think path of least resistance) With the ridge vents closed air will be pulled more evenly from the entire space via the soffit vents if there are enough of them.

I'm not saying they are right, just that what they are saying is a fairly widely held theory.

Personally, I would probably nix the fan and leave the static vents. Or turn the fan thermostat up where it only runs in the very hottest weather. All vents should be rated for flow (usually labeled/stamped on them) and the math could be done to figure if you have adequate venting. Powered fans have fallen out of favor here as not cost effective, but I have installed a bunch of them in years past.

Also... climate/location makes a big difference.

Many factors particular to your house can add variables.



If it ain't woke... don't fix it.
 
Posts: 4118 | Location: Middle Tennessee | Registered: February 07, 2013Reply With QuoteReport This Post
Ammoholic
Picture of Skins2881
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Just left someone's house 20 min ago with bad fan motor. He had two gable vents, housing from previous thru roof AF, ridge vents, soffet vents, a powered gable fan. Told him not to bother replacing motor as it served no purpose and will mess up convection.

Pretty standard info from a AF is 3.4a x 120v x 12hr = 4.9 kwh, or 60¢ per day. If you are going to pay that you better make sure it's effective.



Jesse

Sic Semper Tyrannis
 
Posts: 20758 | Location: Loudoun County, Virginia | Registered: December 27, 2014Reply With QuoteReport This Post
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Picture of smlsig
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quote:
Originally posted by RogB:
We have a 3 story house with a hip roof. The builder put a ridge vent in along with adequate soffit vents. Also have an exhaust fan.

We're now in the process of getting estimates for a new roof. Both roofers that came for estimates recommended that the ridge vent be closed off. They said the soffit vents and ridge vent counteract each other.

I know people have differing opinions on attic ventilation, usually about the pros & cons of an exhaust fan.

But I'm reluctant to seal off the ridge vent. What say the forum?


Absolutely NOT.
In fact, you would be violating code if you didn't have it unless you have a conditioned attic.

As said above find another roofer.

The question is do you have enough ridge line to provide adequate flow? You can go to places like www.energystar.gov and look up the calculations.
If you don't, then a power fan will help but there should not be a ridge vent nearby otherwise it will pull air from that source (least resistance).


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Eddie

Our Founding Fathers were men who understood that the right thing is not necessarily the written thing. -kkina
 
Posts: 6309 | Location: In transit | Registered: February 19, 2013Reply With QuoteReport This Post
Caribou gorn
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Soffit vents and ridge vents are what you want. I don't even think powered fans on T stats meet energy code anymore so they'd have to be continuous or manually switched, if that is even allowed.



I'm gonna vote for the funniest frog with the loudest croak on the highest log.
 
Posts: 10474 | Location: Marietta, GA | Registered: February 10, 2009Reply With QuoteReport This Post
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Additionally, your powered fan can actually pull conditioned air from your home depending on how well things like recessed lights are sealed up. Ridge and soffit vents sized correctly, supplement ridge with hip if necessary (depending on length of your ridge).
 
Posts: 345 | Location: Ohio | Registered: September 08, 2004Reply With QuoteReport This Post
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