Roll Ridge Vent vs. Section Ridge Vent

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Old 11-22-17, 08:27 AM
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Roll Ridge Vent vs. Section Ridge Vent

Hi!

I'm replacing my old BUR with shingles and putting in shingles with a new ridge vent. I bought the 4' ridge vent sections (AirVent's Shinglevent II) because I understood these were the 'best' but when I opened the package I saw the instructions say they are only recommended for roofs with a 3/12-16/12 pitch. As my roof is a 2/12 pitch does that mean my only option is the rolled ridge vent (like OwensCorning Ridgecat)?

Anybody have experience with these?

If it's useful information, I live in the Intermountain west, at an elevation of 3500-4000 feet.
 
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Old 11-22-17, 09:01 AM
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Most ridge vents rely on gravity to keep wind blown rain from prenetrating a ridge vent. On a 2:12 roof you barely have 3/8" of rise from the leading edge of the vent to the leading edge of the slot in your decking. That's not much, so systems that do not block wind blown rain are risky... thus not rated for low slopes.

Besides Ridgecat, similar systems rated for 2:12 are Owens Corning VentSure, and the Cobra "original" rolls of Exhaust Vent. VentSure is a little better product imo, because it is more stiff and doesn't crush as easily as you nail it. But it's all personal preference at some point. All 3 mentioned above work fine or they wouldn't sell and warranty them.

Ridgecat and others like it are rated for 2:12 roofs, mainly because a layer of asphalt roof sealant is placed between the product and the shingle, which keeps water from creeping up the roof when the wind is blowing hard.

Shingle Vent II also includes caulking in their directions, but the difference is that that air slots on Shingle vent II allow water to enter above the area that is to be caulked... somewhat counterintuitive, imo... even if your leave the weep holes open. So the mfg has decided that they will only rate it down to 3:12. This is similar to the rigid 4' Cobra vents, and many other off brands.
 
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Old 11-22-17, 11:39 AM
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Thanks for the quick reply! The literature I see is a bit confusing, as the 'Ridgecat' is also a Ventsure product. But it's different from the rigid Ventsure which is different from the 4' segments of Ventsure. Confusing! So it's a rolled product any way I look at it. I'll be sure to pick up the rigid stuff.

Thanks again!!!
 
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Old 11-22-17, 11:55 AM
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Not what you asked but 2/12 is not typically enough pitch for a roof to be shingled in the first place.
 
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Old 11-22-17, 12:03 PM
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That's not correct stickshift. With 2:12, you simply have to follow the mfg's directions when applying the underlayment. See their directions for their low slope instructions. For example, TAMKO suggests that 2:12 through anything less than 4:12 is considered "low slope".
 
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Old 11-22-17, 12:16 PM
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Works for me.
Thanks X.
 
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Old 11-23-17, 10:00 AM
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Stick,

That's exactly what I thought! I solicited bids from 3 different roofing contractors and they all said I could do shingles if I put Ice & Water shield over the whole decking. We've been liberal with the I&W (under drip edge and over it on the eaves.) I hope it's enough!
 
 

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