Replies

1. 
   jpainter | Jul 27, 2004 09:09pm | #1

   John:

   I don't like the roll type because they tend to be wavy.  I also hate when roofers don't bring the vent profile all the way to the end of the ridge-- it looks stupid to me, like they were too cheap or too lazy to finish the job!

   Anyway, you should install a continuous soffit vent with the same airflow rating as the ridge vent if site conditions allow.  Then lose the gable vents and fan or the ridge went will draw from those areas and the cooling effect on the whole roof will be diminished.  At LEAST turn off the fan.

   J Painter

1. 
   slykarma | Jul 28, 2004 05:31am | #5

   It's all in the eye of the beholder I guess. I prefer to NOT continue ridge vent to the gable end because it looks odd from the ground, sort of industrial somehow. I'd rather see a clean straight line to the ridge when looking a tthe gable end on.

   The coil style (Cobra is the most common brand here, part of the GAF system) seems to have the same cross sectional area as the plastic style and they both cost the same. The Cobra vent comes with dedicated fasteneers that have a spacer built in to prevent crushing and loss of air flow. Either system will look wavy and uneven if you don't snap a line along the ridge to keep it straight.

   Lignum est bonum.

1. 
   wrudiger | Jul 28, 2004 08:26am | #6

   I am interviewing designer/builders now for remodel that includes reroof.  I ask every one about ridge vents, 'cause they seem like a good idea to me. 

   So far responses are running 80% against for various reasons (leak in cross-wind, not enough square area for good venting, not wide enough to adequately attach to roof are the main ones).  This may be due in part to where I live (San Francisco / East Bay) or lack of quality ridge vent choices here or their own ignorance (most are not able to answer the question "How do you keep up with changes in building technologies and best practives?").

   However, several did strongly recommend "Eyebrow" vents.  Not sure what those are but they seem to be more popular here. 

   Anyone here used these? How do they compare to ridge vents?

1. 
   xMikeSmith | Jul 28, 2004 01:18pm | #7

   rudiger.... we live on an island in the atlantic... ShingleVent ii does not leak and has more proven flow than the competition

   try this link and look for ShingleVent II

   http://www.airvent.com/homeowner/whyVent/types.shtml#Mike Smith   Rhode Island : Design / Build / Repair / Restore

1. 
   seeyou | Jul 28, 2004 02:56pm | #8

   Mike,

   How much snow do you get? I've had to replace ShingleventII twice because of fine wind driven snow entering. I couldn't ascertain any installation or product flaws either time. I've never had a problem with Cobra roll type. It does take some care to install to make it look good.

2. 
   xMikeSmith | Jul 28, 2004 04:41pm | #9

   does your SVII have the blue filter fabric ?   we get a lot of snow or none at all... one year we had 27 snow storms... so as soon as everyone and their brother bought a 4 wheel and a new plow , it didn't snow fro the next 3 years...

    wanna buy a plow ?

   i personally don't like cobra, no baffle.....and no test results to show air flow (maybe i missed the test results ?)

    i've been an AirVent  user since about '78.. and i do remember fine snow.. but none since they put the filter fabric in...Mike Smith   Rhode Island : Design / Build / Repair / Restore

3. 
   seeyou | Jul 28, 2004 11:48pm | #12

   It's been several years since l've used SVII. I had two problems in the same storm. None since. One of them was installed by my guys, one by someone else. No other problems. Don't know the spec's on Cobra, but I've got it on my house and can tell a difference since I installed it. 1750 sq ft of attic (5/12 hip) with one static vent before I installed the Cobra.  Other brands may perform better. I've also used Ventsure by OC and like it pretty well.

4. 
   xMikeSmith | Jul 29, 2004 12:40am | #13

   green.. if i had to guess, i'd guess that Cobra is the number 1 selling ridge vent.. hand's down..

    but i really, really like SVII....

   course.. now i'm trying to get rid of roof vents whenever possible and just go with hot roofs...so.. if i need to vent because of code or customers, i use vented soffit, baffles ( like PropaVent)  and SVII on the ridge

   s Mike Smith   Rhode Island : Design / Build / Repair / Restore

5. 
   DanH | Jul 28, 2004 05:51pm | #10

   We've had ShingleVentII for 10 years now and never had a problem with any significant amount of snow blowing through (this in SE Minnesota).

   Unfortunately, the shingles themselves haven't held up nearly as well. (We got some of the bad batch of Certainteed shingles.)

6. 
   captainjohn | Jul 28, 2004 08:50pm | #11

   Just wanted to say thanks to everyone for taking the time to respond to my questions.

   John

2. 
   hammer | Jul 28, 2004 01:21am | #2

   John;

   Nothing better or less maintenance than ridge vents. I prefer the plactice 4' sections. The ones that look like a sponge won't move the air. As was stated, make sure to have adequate continous eave vents. Make sure the insulation is free of the air cases with using poly chutes, etc.

   remove and cover the old vents and if your re-roofing take the power fan out.

   Interesting how some people belive they save money with fan venting a attic. What does that fan run on?

3. 
   Hubedube | Jul 28, 2004 01:26am | #3

   As long as you have proper R value insulation in the attic area, you can NEVER have too much ventilation. A general rule of thumb is: for a 2/12 or greater roof slope you need a minimum of 1 sq ft of vent to every 300 sq ft of attic floor area. The more the better ........

   50  percent is coming in via the soffits and 50 percent going out via the ridge or other high positioned  vents. Don't be concerned about adding more vents to the gable ends as since hot air rises, the more the better. Gravity is still the best and most economical approach to venting a roof's attic space. Some home owners HAVE to add gable Fan assisted vents because some builders tend to skimp on the amont of required ventilation in the first place, thus the addition of an un-necessary fan... Good luck   Hube

1. 
   xMikeSmith | Jul 28, 2004 05:12am | #4

   when we use a vented roof.. we use soffit vents and ridge vents.. the gable end vents must be blocked or removed..

    the only brand we will use is ShinglVent II.. they have a baffle , a filter, and complete testing to prove their efficiency....

    none betterMike Smith   Rhode Island : Design / Build / Repair / Restore