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Roofing/ridge vent vs. O'Hagen eyebrow vents for a cathedral roof


I explained to a roofing contractor we asked a bid from to offer us a new bid as the estimator didn't pay attention when I told him we have a cathedral ceiling but the original 1979 home builders hadn't installed any venting for the roof. Our roof right now evidences 4x4 sized concave depressions on the Ocean facing side of our roof. The woman who owns the company got back to me, saying they'd spoken to other roofing companies in our area and found out that in our case,on our hillside very near the ocean just South of S.F., a ridge vent ran a risk of allowing in driven rain during the hard rain storms that aren't unusual here.  She said that eyebrow vents (they submitted a new bid stipulating the installation of 4 O'Hagen eyebrow vents instead of a ridge vent), were a better solution. Does this make sense to you?

Ventilation is a very tricky situation. The best way to ventilate is to have even ventilation on the intake (eave or downslope end) and on the exhaust (ridge or upslope end). Each space - in the case of a cathedral ceiling this means each space between the joists - is required to have ventilation. This would mean that they will need to have the dormers include all of the spaces - I have no idea if 4 dormers is enough. I would stick with the ridge vents - they seem to be the best method of obtaining the correct amount of ventilation, particularly in a cathedral ceiling situation. There are different vents that have rain deflecting devices if you are concerned about wind driven rain that should mitigate any concern you have.
The biggest trick is insuring that there is air moving by equal intake/exhaust and insuring that the air moves correctly - there should be air space above the insulation and below the wood sheathing. If the insulation is pushed up against the wood, the air will not move anyway.
Good luck,


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Aaron Nelson


All types of questions with regard to roofing, waterproofing and sheet metal. This includes commercial and residential buildings, along with the various aspects of the construction means and methods, ventilation, steep-slope or low-slope, code requirements, installation errors and other such problems


I started in roofing fabricating and installing sheet metal flashings out of high school for a large commercial contractor. I worked for the same contractor in the office estimating and project managing commercial project for 10 years. I left the construction side of roofing and now work as a roof consultant, which I have been doing for 8-years.

RCI, Inc.

I am a Registered Roof Consultant (RRC) and a Registered Roof Observer (RRO) through RCI, Inc. RCI is a international group of building envelope professionals. I am an approved instructor for RCI educational programs.

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We have worked with many local school districts, insurance companies, HOA's, building management companies, and we have a national client with buildings located throughout the US.

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