Ridge vents in snow


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Old 02-23-04, 10:31 AM
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Ridge vents in snow

I would like to get opinions on the effectiveness of ridge vents in areas with a lot of snow.

I'm looking at the roof of the storage shed and the 3 season porch I built a few years back that have ridge vents. Both ridge vents are covered with about 8" of snow and that snow has a pretty good crust on it now. I have to seriously question whether they do any good in the winter; in both of my cases it probably doesn't matter because they are both over unheated spaces. But what about houses where it does matter? Has anyone seen any kind of independent testing done for this? I've thought about asking the manufacturers of the ridge vents, but their business is to sell them, so...

I should probably know this myself, but I do only commercial design, so has not been something I've ever had to research. So, folks, what do you think?

Bruce
 
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Old 02-23-04, 02:42 PM
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Generally, I don't like to put ridge vents on any slope less than 6:12, and am happier with 8:12 and up. Since in our area it is not unusual to get more than 12 inches of snow on a roof, the ridge vents on a lower slope will be completely covered. If the slope is steep enough, the snow will end up moving/blowing lower down, and the vents will not be obstructed.

In our area, a product known locally as the "Maximum Vent" is very common, mainly because it has a vertical shaft about 1 foot high, topped by a series of shielded louvres. The height puts the air openings above most of the snow. Looks rather ugly and bulky, but works very well in snow country.
 
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Old 02-23-04, 03:11 PM
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You will probably get a bunch of answers to your question. It seems like ridge vents is always a touchy subject. Of course, most know my opinion of ridge vents. I always say "Why would anyone cut a hole in a perfectly good roof, just to insert another hole in it" ? Just my opinion. Good Luck
 
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Old 02-24-04, 12:42 PM
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Dont like them ,dont use them. Most of the time when you look up in the attic. The guy that put them on left the felt over the little hole he cut anyway .Also on one www. There was talk about a wind test . That the wind from one side like would block the the vent off so no air would get into the attic from the lower vents like from the over hang ED
 
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Old 02-28-04, 07:58 PM
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If there is enough volume of air moving through the system, it will usally not plug up all of the way. The intakes (soffet vents) must be bigger than the area of the ridge vent. The plenum along the ridge must be unblocked. Sometimes the entire ridge will be buried except for a "hole" where the vent is blowing. In sun Valley, true cold roofs with 3 1/2" air spaces work under many feet of snow.
Jim
 
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Old 03-01-04, 03:16 PM
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Jack & Ed..

In your opinion's What is the best way to vent the attic space without a ridge vent? I was going to get Ridge Vent II

Thanks
 
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Old 03-02-04, 04:45 AM
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I believe that standard gable vents are best. Ratio of 1:300, 1:150 is better.
Jim
 
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Old 03-02-04, 04:10 PM
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Mike I think you said you had hip all around. So you can take and go out on two of them with what we 'd call a false gable. This well give you lots of air. On that 1 to 150 sq 1/2 in and 1/2 out. You'l get that roof on yet . ED
 
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Old 03-02-04, 04:50 PM
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No Ed. Its a simple split level home with gable ends and a addition off the back with a third gable. The addition has vaulted ceiling so it needs a ridge vent I think , but has none. Iv got that cupola drawing still Ed. But my home is not the right style for one.

Gable end vents work well for that corner of the roof but not for the whole roof from what Iv read. Mine has a 52 foot ridge.

I was just wondering if the moderators & pros here liked mushroom vents (lamanco 750's) better than ridge (shingle vent II or trimline).
 
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Old 03-03-04, 04:40 AM
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One of the reasons I started this thread is that I have gable ends on my home with louvers. I was debating if I should add a ridge vent, but I don't think I will after reading the replies and seeing the snow covered vents I have on my 3 season porch.

GiantScale: With vaulted ceilings, I sure don't see a good alternative to ridge vents. In fact, my 3 season porch has vaulted ceings, which is why it has a ridge vent. The only other possibility I can thing of is some type of structure at the peak that would allow the installation of a continuous louver. Would be a tough design problem to make it look like something, though, and not sure if it wouldn't drift over with snow anyway.

Bruce
 
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Old 03-05-04, 04:44 PM
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Some jobs have cupalos (sp) or "birdhouses" built periodically along the ridge, every 40" ft or so. A plenum must be cut into the roof framing (roofed over) and soffet venting is required. The louvers are in the sidewalls of the cupalo. I did one of Copper 4" shingles with a weathervane on top a few years ago. It was about 3' high. The Stien Erickson Lodge in Deer Vally has these...they get tons of snow.
Jim
 
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Old 03-05-04, 05:54 PM
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So we could get a good vent set up there above the vaulted ceilings. Is why we went to the scissors trusses years ago.

ED
 
 

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