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Question DetailsAsked on 5/16/2013

Are Roof Ridge Vents good?

I am interested in a GAF Cobra Ridge Vent or a the Vent Sure by Owens Corning and am wondering if they are any good and will hold up?

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9 Answers

1
Vote

Acontinious ridge vent is the # 1 cheapest, best, investment in your homes health and energy conservation. Every day it allows the attic of your home to vent. In the summer warm air and even more important in the winter the moisture that used to build up in the insulation (and greatly reduce its effectiveness). Remember to feed it by installing soffit vents with shutes to keep the insulation from clogging the airflow, Shutes are available from big box stores, (lowes etc) and staple between the roof rafters. Soffit vents are usually aluminum louvered and cut into the overhang. Talk to utility company for ratio of vents to continious ridge vent. Do Not use gable vents to feed air to ridge vent. It defeats the purpose of pulling air from the the attic, If possible close them off from inside. Handyman can provide the labor or you, Use a plastic rake in the attic to move insulation. See my blog on radiant barriers for further energy conservation tactics.

Jim Casper Old Energy Auditor

Source: www.heartlandmastershield.com

Answered 3 years ago by jccasper

0
Votes

Absolutely! The lab tests show that ridge vents coupled with soffit vents do more for the ventilation of your attic than other options. This is backed by real-world tests. As air heats in your attic it rises, pulling fresh cooler air from the soffit vents. The hot air escapes through the ridge vent. The overall temperature of your attic is decreased. It's as simple as that. Gable vents are more dependent on cross flow air from a breeze. Simple "turtle" vents work the same way as the ridge vent but don't allow the hottest air collecting at the peak of the roof to escape.


Todd Shell

Todd's Home Services

San Antonio, TX

Answered 3 years ago by Todd's Home Services

0
Votes

I agree with the first two answers! Good advice in both.

Source: www.bayareacool.co

Answered 3 years ago by BayAreaAC

2
Votes

A couple of hints on ridge vents:

1) In snowless or no-snow regions Do Not continue them out the ridge to the overhanging eave portion - it weakens the plywood sheathing connection and can cause your roof sheathing to peel back in this area in heavy winds. You do not need them here anyway - only the enclosed attic portion needs them. In areas with roof snow load common in the winter, continue them to the end of the roof ridge but do NOT cut away the sheathing below them in the overhang area. Explanation why in 2) below.

2) Be sure the ones you are getting have a labyrinth cross-section or exterior baffle that will trap blowing rain and snow. Snow especially (although storm-driven rain can too, especially in thunderstorm and hurricane prone areas) blows up along the roof right in under the ridge vent overhang, so if it is not designed to trap that snow and water and direct the water back onto the roof it will end up in your attic insulation and ceiling. I don't have enough fingers and toes to even begin to count the number of times I have seen cheap direct shot ridge vents or the "steel wool" appearing mesh ones let masses of blown snow into an attic. In one there was over a foot of snow standing on the insulation - and of course melting down into the house below.

3) In the case of a house with good attic insulation, there is not a lot of heat in the attic, so the ridge vent does not melt the snow and can have winter-long snow cover. This is VERY common where you have about 8 inches or more of snow cover for extended periods of time. In my area, you can tell the moderately to well-insulated attics by their ridge vents being fully snow covered and useless all winter long. This means, if you have closed off your gable vents, that household moisture coming into the attic (and there will ALWAYS be moisture) is trapped inside, and builds up as frost on the top of (or within) the insulation and on the underside of the roof. I have seen up to 6 inches of frost buildup from this.

Therefore, for this reason I use three things in my designs for heavy snow areas like where I live:

1) run the ridge vent full roof length and leave the ends open, so the two ends are exposed to open air and not buried in snow pack, allowing end venting. However, do NOT cut the sheathing gap slot in the gable overhang section - just apply the ridge vent over the sheathing and ice and water shield, to provide a vent area in an area where the snow commonly metls off faster. This works only with vents tht have a continuous opening down their length - with the cross-baffled type with no central opening this does no good.

2) leave the gable vents open. This does not really hurt the eave-to-ridge venting, as the most significant part of that airflow occurs in the space between the joists right under the roof, and the gable-to-gable or eave to gable air passes underneath that zone. Also, if moist or hot air escapes through the gable vents rather than the ridge vent, it is still gone. Also, gable vents only work significantly when there is at least a small breeze or pressure differential between ends of the house, in which case natural drafting will be sucking much larger amounts of air than usual through the ridge vents at the same time anyway.

3) I require an ice and water shield strip (typically about 8-12 inches wide), covering (and stapled to) the edge of the sheathing vent slot at the ridge, downslope past the edge of the ridge vent, and exiting on TOP of the shingles at the downslope edge of the vent. What this does is capture any water from snow and rain dropping within the vent and keep it from getting on the exposed shething at the slot or under the shingles, and carry it away back to the roof surface. Some ridge vents have a solid aluminum or plastic bottom base piece that does this so the ice and water shield is not needed in that case.

I have not seen Cobra vents but from the pictures I found, it looks like they are wide open to snow and rain infiltration like the mesh ones - although maybe the Snow Country version is better - could not find a closeup of the design. Vent Sure I have used and like - it has good baffling and moisture shield to prevent water from getting down into the attic.

Source: http://www.finehomebuilding.com/how-t...

Answered 3 years ago by LCD

2
Votes

Do not use the roll out Cobra vent. That system, even slightly mis-installed, can create huge issues but not venting properly.


Be sure to use one of the rigid systems like the Snow Country, AirVent, or the OC venting system.



Answered 3 years ago by WoWHomeSolutions

1
Vote

The GAF Cobras are used by the very best roofing companies in our locale - rare snow here when coupled with adequate soffit venting.


They have both the fabric defense as well as maze design openings.


The installation is flawless if the installer is experiences, trained & certified.


They hold up and also are semi protected by the shingles themselves.


As you are aware, you can upgrade these shingles that top this vent.


The ridge vents are only allowed within a foot of a protruding wall or end of attic space below; they should be capped at ends, else 1) rain will blow inside, 2) wasps love to build nests here = dangerous for roof maintenance later.


These have the type of base that do not require special underlayment weaving into the shigles - shingle as normal ... that said, any roof penetration or valley deserves the sticky backed Ice & Water shields


Gable vents should care for heavy snow venues' attic humidity problems


When solar venting caps become less costly, the payback numbers might make these a solution for those lving in improperly designed/vented housing.

Answered 2 years ago by tgivaughn

0
Votes

If the best roofing companies in your area are using a Cobra vent, I hate to see what the bad ones are using.


Cobra vent is crap. It isn't baffled, it doesn't flow as much CFM as the rigid vents do, its subject to installation error, its ugly, etc...shall I go on.



Answered 2 years ago by Davidhughes

1
Vote

GAF Cobra offers many vents, thankfully even one that competes with Fypon's fascia vent when soffits are nil

but

back to you ...

I'm sure it's tempting to some in your area to buy the cheapest vent Cobra makes then hang/burn the Cobra name universally.

TO put a finer point on Cobra being used by the best + "no baffles" what I referred to was

http://www.gaf.com/Roofing/Residential/Products/Roof_Vents/Cobra_Rigid_Vent_3

and anyone with a finger can test out these baffles

anyone with an eye can appreciate the shingles appearance


I doubt anyone could be a hater of this Cobra 3

but I realize that shrimp lovers can come to hate this food after just one bad experience at a cheap drive through diner.


Answered 2 years ago by tgivaughn

0
Votes

Proper attic ventilation is a key component of a well thought out roofing SYSTEM. The first question to answer is "Do I have enough ridge length to use a Ridge Vent exhaust system?"

A good roofing company can determine the how much ventilation your attic space will need for both intake and exhaust ventilation. Once they have calculated this, they will be able to advise what the best intake/exhaust vent options are for your home.

If your roof has enough ridge length to use a Ridge Vent exhaust system, I would suggest a product with a baffle set up that does not have an inner cloth liner. The baffle combined with a good breeze will create a low-pressure effect that will PULL air out of your attic space. Inner cloth liners or filters tend to clog in areas with large amounts of dust or pollen in the air. (You change your homes air filters every 6 months, If you have a filter on your exhaust vent you can't expect it to last as long as the other parts of your roofing system.)

If I had to recommend a ridge vent: Lomanco Lo-Omni Roll. This fits the requirements and is a low profile, easy to install product.

*Proper attic ventilation test: is your attic space approximately the same temperature and humidity level as the outside air? If the answer is No, there is a problem with your ventilation system.


Great Video explaining the baffle system.


Calculate your needed attic ventilation.

Answered 1 year ago by KnowledgeBase




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