Recommend a ridge vent?

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Old 07-02-15, 08:27 PM
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Recommend a ridge vent?

Hello,

I am looking around to buy some some specific ridge vents, hoping to find recommendations for a specific brand and model. There are more than a few to choose from and I really don't know which is garbage and which will last.

Can you recommend some ridge ventilation to me?

Thanks
 
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Old 07-02-15, 08:41 PM
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Hi GD,
I don't do shingles since they
u almost killed me 40 years ago. I guess I hear style discussed most often which in turn points to some specific brands. Air vent offers an air deflector which they claim will increase the wind generated ventilation.
Air Vent: Ridge Vents

Others might be targeted towards preventing snow and rain intrusion.

What is the slope of your roof and is it all high ridge or any hip ridges?

Others may comment on what they prefer to use.

Bud
 
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Old 07-02-15, 10:43 PM
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Hello,

Thanks for the reply.

u almost killed me 40 years ago
I didn't do it.

What is the slope of your roof and is it all high ridge or any hip ridges?
I am not up on all the roofing talk, but I think the answer is a gable roof. The height from the top of the top plate to the gable peak is a few inches shy of 4 feet, I am guessing this will translate into the pitch or slope somehow.

The ridge vent is going on an attached garage, of which the ridge itself is around 20 feet.

Others might be targeted towards preventing snow and rain intrusion.
Some people are sooo picky. (sarcasm)
 

Last edited by chandler; 07-03-15 at 03:50 AM. Reason: Removed unnecessary gif
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Old 07-03-15, 03:53 AM
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As far as specific brands, it would be difficult to narrow down to which is better. Interlocking 3' ridge vents with the capability of tacking on your own shingles seem to be the best aesthetically. Snow and ice dams present their own problems up north, since they can become blocked and inefficient. Since you are really up north, that may be a large concern.
 
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Old 07-03-15, 11:12 AM
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As far as specific brands, it would be difficult to narrow down to which is better.
It's why I asked, I am sure someone has some deeper insight, has done some comparisons and so on. How else are decisions on which product to use made?
 
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Old 07-03-15, 12:35 PM
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Snow country, low pitched roof, and gable construction.
Do you have a strong wind exposure perpendicular to the ridge where snow and rain could be issues?
Has the attic been vented with traditional soffit and gable vents?
Have you done the calculations for targeted total vent area?
How much NFA do you have for the low vents, assumed to be soffit vents?
Is it a shingled roof?
Are you replacing the entire roof (shingles) or just retrofitting a ridge vent?
Have you air sealed the attic floor, the floor to ceiling below?

What you choose can be based on more than performance. If the one you select is only available 400 miles away and that is where you would have to go for warranty, it might fall down on the list. If a contractor is installing this, they may have a preference and may also have some performance input.

Bud
 
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Old 07-03-15, 07:43 PM
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Do you have a strong wind exposure perpendicular to the ridge where snow and rain could be issues?
I doubt I could answer this question, but I imagine wind has strongly blown in all directions of my home.

Has the attic been vented with traditional soffit and gable vents?
The application is for an attached garage, the house has ventilation, the garage has zero. The attic will have ventilation, but not until I choose the ideal products, which is largely why I made this thread.

Have you done the calculations for targeted total vent area? How much NFA do you have for the low vents, assumed to be soffit vents?
I have. 105.6 square inches low vents for the 150 rule (which I think can apply here) and 211 square inches for the 300 rule.

Is it a shingled roof?
Yes. https://imgur.com/a/HegHp

Are you replacing the entire roof (shingles) or just retrofitting a ridge vent?
Retrofit.

Have you air sealed the attic floor, the floor to ceiling below?
My plan has been to complete the ventilation before insulating and putting up drywall, so no sealing of any kind has been done. I do plan to use a vapor barrier along with ideal levels of air sealing once the insulation is complete.

What you choose can be based on more than performance. If the one you select is only available 400 miles away and that is where you would have to go for warranty, it might fall down on the list.
I am hoping anything anyone might suggest can be shipped to me if needed. Thanks.
 
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Old 07-03-15, 08:43 PM
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I was just doing some reading and watching this video:
The Best Venting Ridge Vent - United Home Experts
Although the video appears to be of Air Vent origin, the University of Florida is well recognized for their many contributions to the energy sciences.

"I have. 105.6 square inches low vents for the 150 rule (which I think can apply here) and 211 square inches for the 300 rule." I'm not clear on this statement. Divide the area of your attic floor by 150 to get your total targeted vent area and then divide that number by approximately half high and half low. A 25' square garage would have 625 ft of area. Divide that by 150 and you have 4.16 ft of total suggested vent area (NFA). Using half high and half low you would need 300 in for low vent area and 300 in for high. This would be for the 1/150 guideline.

For the 1/300 guideline the suggested areas would 1/2 the above.

NFA for ridge vents will vary, but many use 18 in per linear foot. I think that is a bit high, but that is another discussion. So, your high vent requirement looks like an easy number to meet, even using the 1/150.

But, looking at the picture, that soffit shows only one small vent strip. I assume that something different will be used.

If you can bring your low soffit number up to match the new ridge vents you should have more than enough venting, especially for a garage.

To reduce costs, it should fine to use less than a full ridge of vent material, maybe half?

Bud
 
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Old 07-03-15, 11:49 PM
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I was just doing some reading and watching this video:
I actually checked out their channel not long ago. I am not saying I know their products to be good or bad, but the internet is filled with shills and astroturfing. The reason I make threads like this is I hope to learn about these things from those with unbiased opinions.

I'm not clear on this statement.
I mislabeled the 150 rule and 300 rule bits.

Here is the math I used for each.

The 1/150 rule;
20'x22'=440 square feet.
440/150=2.93
To convert to square inches I multiply by 144. So 2.93*144=422.4 square inches.
Take 422.4 and divide by 2 to find the high and low, which brings me to 211.2.

The 1/300 rule;
20'x22'=440 square feet.
440/300=1.47
To convert to square inches I multiply by 144. So 1.47*144=211.2 square inches.
Take 211.2 and divide by 2 to find the high and low, which brings me to 105.6.

But, looking at the picture, that soffit shows only one small vent strip. I assume that something different will be used.
That soffit strip is blocked, there is zero ventilation. I haven't settled on the soffit vents yet, but I feel like making that decision alone is much less risky.
 
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Old 07-04-15, 03:09 AM
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Your math is good. Your choice as to 150 or 300. Being a garage it could be subject to periodic heavy snow and water from vehicles, for which you might want the 150. But, no showers, cooking, or people adding to the daily humidity.

As far as the 150/300 rules, they evolved from 1942 and no one what criteria was used to pick those numbers and no one has bothered to test to see if more or less is better. All we have is the test of time and the fact that codes have adopted them. As for the 50/50 divide the only reasoning for anything different is one engineer proposing 60% low with 40% high in cold climates to lower the pressure differential across the ceiling plane. Again, being a garage it probably makes little difference.

I realize you would like a roofer to speak up and say, use this brand and why, so I'm keeping the thread at the top to see if that guidance is coming.

Bud
 
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Old 07-04-15, 06:35 AM
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While I have been reluctant to advocate one brand over another, I have used this brand and it works well with prescribed ridge shingles in the complimentary color. Builders Edge 11 in. x 48 in. Ridge Vent Plus (10-Pieces / Box)-151000000002 - The Home Depot

Now, as disclaimered, these were used in the South. Who knows what your loads and blockages will be in the winter? Sooner or later you will need a very local observation by a professional roofer to determine the best in your neighborhood. Looking to us for a definitive answer is like looking at a YouTube video. We can't possibly cover all the bases you want covered from a distance and in generalities.
 
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Old 07-04-15, 06:46 AM
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I am personally fond of these vents

Roof Turbine Vents | Ask the Builder

I have seen too many issues with ridge vents in a northern climate that I try to avoid them when possible. Plus I dont believe they have nearly the venting capacity they claim to have.
 
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Old 07-04-15, 06:57 AM
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Turbines with higher clearance would make a better choice, IMO. How do they handle the snow pack, etc., Keith?
 
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Old 07-04-15, 07:00 AM
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I have never seen one get blocked by snow ( which is the main reason I don't like ridge vents ). Of course, under extreme snowfall conditions, it is possible for it to become snow packed, but that is the case for just about any roof vent. Most snowfall events happen with wind anyway, so I am guessing the turning of the vent helps prevent snow from packing around it.
 
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Old 07-05-15, 01:03 PM
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I work for a lumber yard in NE Ohio and 80% of our roofing contractors use a continous rolled ridge vent. Try Lomanco's Omni Roll or the Venture product by Owens Corning.

The Lomanco product can be installed with an air nailer, and both products are covered with a color matched shingle.

As for ice damming, I have never heard of it occurring at the ridge in my part of the country. If it is an issue then something more serious is going on.

Center vent vinyl soffit is the bulk of the local market for intake ventilation. They are only required at the eaves, but occasionally will be run up your gables as well. If you don't use center vent soffit, use one full vent soffit for every three solid soffits.

Best of luck!
 

Last edited by Perryjr84; 07-05-15 at 01:04 PM. Reason: Grammar
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Old 07-05-15, 01:22 PM
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As for ridge vents becoming totally blocked I agree it is rare, at least here in central Maine. When we have snow I like to take note of how heat loss patterns are showing up and how ridge vents are doing. In most cases the worst that occurs with the ridge vents is one side gets blocked, but they usually clear within a day or two. Except one particular snow storm this last winter, a combination of sleet and snow that fell straight down, no wind. That storm left 3 to 4" of snow on top of all ridge vents and blocked them solid. And, they remained that way for several weeks. However, that was a rare occasion and I did see a few home owners take note and reach up there with roof rakes and clear some of that snow away.

I will assume the 2' snow storms do block many as well, I just don't bother looking.

Bud
 
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