Robert Allison wrote:
JD wrote:

I'm in the process of getting a new roof and the first roofer wants to
install ridge vents, which I wasn't familiar with. I've done some
research and ridge vents seem to be a good idea? I have some questions:

I have a hip roof so do the ridge vents go on every ridge or just the
top or highest ridge?

It goes on every ridge that is over attic space. The "ridges" on the
side of your hips are not ridges, but hips.

I found a web page that talks about the relationship between the
amount of ridge vent and number of soffit vents.

http://www.rd.com/familyhandyman/content/18231/0

If you scroll about half way down the page they talk about Minimum
Venting Requirements. Is the information they provide correct? It says
a 1,500 sq ft attic will need 10 sq ft of venting, half on the roof
and half on the soffits. They say the factor is 1 sq ft of venting for
each 150 sq ft of attic. Is that correct?


It is a good rule of thumb. As much as you can get is the better answer.

The key being one needs the same amount of soffit and roof vent Net Free
Vent Area or you have bad ventilation. The upper vent can't remove more
than the lower vent can provide. One needs an equal amount of in and out
vents. No? It's a flow problem.

--
JD..