Replies

1. Expert Member
   Dana Dorsett | Jul 07, 2019 12:51pm | #1

   Snow is air permeable, and the depths at ridges are small. Even if temporarily restricted by a big dump of maritime sludge snow, it clears in PLENTY of time. At the snow density and depth of Spokane snowfall this is NOT a problem.

   For a building at say 5000' on the western exposure of Mt. Baker it could theoretically be an issue in a high snow year, but even then the ridge vent isn't the greatest concern.

2. 
   Jon_R | Jul 07, 2019 12:57pm | #2

   I believe that you are in an area with a light enough snow load (< 60 lb/ft2) that, with proper R-value and air sealing, venting is optional for preventing significant ice dams. So don't worry if the vent is sometimes restricted.

   Measurements indicate that snow blocked venting does increase attic temperature, so in heavy snow areas, it's a legitimate concern. An option to solve this is to enclose just below the ridge (a mini-attic) and use gable vents in this.

3. 
   JohnBovey | Jul 07, 2019 04:32pm | #3

   Thanks for the replies. Just logically thinking about it, it seems like something more arched like this (https://www.lowes.com/pd/Owens-Corning-VentSure-15-in-x-48-in-Black-Plastic-Stick-Roof-Ridge-Vent/3311988) would be better than something more flat like this (https://www.lowes.com/pd/Air-Vent-14-in-x-48-in-Black-Plastic-Stick-Roof-Ridge-Vent/50113110).... right?

   The pictures for both look like they could easily be clogged, but I've never done this before, so I'm not sure. Appreciate any additional thoughts you all have.

1. Expert Member
   MALCOLM TAYLOR | Jul 07, 2019 05:06pm | #4

   I'm pretty sure those are the same vents. One is just shaped for steeper pitched roofs than the other.

1. 
   JohnBovey | Jul 07, 2019 05:21pm | #6

   Malcom Taylor: That's what I was thinking at first too, but then in the Q & A section of the more arched one, someone asked, "What is the maximum pitch that this can be used on? It says virtually any pitch. However I have 12's and 16's on my roof & want to make sure it works." The reply from OwensCorning was, "...the VentSure 4-Foot Strip may be installed on roof slopes of 3/12 to 16/12."

   Our roof will be a 4/12, so it seems like it would work, but it might look a bit odd... if you look for that sort of thing. Thoughts?

1. Expert Member
   MALCOLM TAYLOR | Jul 07, 2019 07:34pm | #8

   You are right they have slightly different openings at the bottom.

   I've used similar ones. The only problem I had with them was they clogged very easily with conifer needles. I prefer this design, although it does mean you can't cover the ridge vent with cap shingles. https://www.pac-clad.com/products/airflow-systems/pac-ss-ridge-vents/

1. 
   JohnBovey | Jul 09, 2019 09:22am | #9

   Malcom Taylor: Is that link you provided just for metal roofs? The pics. on that site seem to indicate so.

   Thanks.

2. Expert Member
   MALCOLM TAYLOR | Jul 09, 2019 11:17am | #10

   If you look at the diagram below the photo on the link I provided it shows the vent on a shingle roof. How that looks is an open question.

4. 
   Deleted | Jul 07, 2019 05:20pm | #5

   Deleted

5. 
   730d | Jul 07, 2019 07:05pm | #7

   My question is how much of a concern is it for ridge vents over a cathedral ceiling to get blocked by snow?
   Not much, they open fast and vent as designed in short order. In my experience. Unfortunately I have climbed around a a few in the winter.