[sparksie]

We are looking at replacing the shingles on our roof. One of the contractors that came out to see us said that the 2 whirligig vents on our roof would have to go; he felt they weren't any good and he would replace these 2 vents with 5 flat square vents. While talking to a friend who is a bit of a do it yourselfer he said that a ridge vent is the way to go. What is better or is it simply a matter of preference?
:huh:

 

[seeyou]

A properly sized system is more important than type.

Go here for sizing specs:
http://www.airvent.com/professional/whyVent/evaluate.shtml

 

[Slyfox]

Both turtle vents {flat square} and ridge vents work when installed properly.

With that said, better then 90% of newly built homes I roof will have ridge vents installed.

On re-roofs {tear offs} we either add to additional turtle vents or switch over to ridge vents.
In my area it's very rare to find a home built prior to the 1980's with proper ventilation, unless the situation was corrected during a re-roof.

Proper ventilation:
1. Intake
2. Unobstructed Air Flow
3. Exhaust

 

[Grumpy]

Attic ventilation is a science unique to the architecture of each building. There are no one size fits all solutions. I agree with the above posters, that ammount of ventilation is more important than type of ventilation. A common problem I see with alot of my competitors is that they like to spec ridge vent on EVERYTHING. Personally very few of the hip roofs that we shingle have long enough ridge lines for adequate ventilation via a ridge vent. Therefore we must spec something else on these projects.

I personally prefer ridge vent, but won't install it if I can't acheive enough Net Free Area, or if there is no intake. There are means of creating an intake but sometimes it's more cost effective to double up the mushroom/turtle vents to acheive the proper NFA. Having said that, all ventilation will work better with intake, some ventilation like ridge vent won't work at all without on intake.