I have a hip roof with less than 10 ft of ridge so I have pot vents. Would adding a ridge vent help or would it just interfere with the pot vents working properly?
The more venting the better, but I wouldn't spend too much on a ridge vent if it isn't really needed. What's a pot vent? Is that like a turbine type?
By pot vent I mean those cheap metal square things like the following. I have 10 of them on my roof (5 on each of two sections) and the home has about a 2400SF perimeter
Sorry I didn't save the source, but when I was doing the roof on our hip I found an on-line formula that was very clear about how many square inches of unpowered vent would serve. I have only 14 feet of ridge, but used a vented shingle, plus I bought several good-sized "turtle" vents and kept the two little ones that the house originally had.
I also went to some trouble to improve the soffit venting. I think it's paid off in the living quality of the house, and it should help ensure that the asphalt roof lies flat for a long time. (We bought pretty good architectural, long-warranty shingles, and figure there's no point in undermining their useful life span with poor installation. I told my wife it was my last roof, and I hope I'm right!)