I just had my roof replaced and while doing so I had ridge vents installed to replace the two turbines and two turtle vents. The work was done on a cloudy cold day and by a crew of seven men. I was completly overwhelmed by the speed in which they worked and tried to keep an eye on the job, but that is hard to do. when the weekend came, the weather turned sunny and hot and as I was inspecting the job more closely, I noticed that the ridge vents do not run flat and uniform, but have three humps and as the day progresses and the sun gets hotter, it becomes full of humps and waves. This does not impress me and makes me wish I had not went with the ridge vents, but stayed with my old style vents. Does anyone have an answer as to why my ridge vents do not stay flat and straight? I have neighbor, two doors down that had the same work done, last week, by another company and her ridge vents are always perfect. What gives?
My guess is that your neighbors is actually nailed down into the roof sheathing and that on yours the nails were too short or missed. Can you get in the attic and see what the ridge area looks like from below? Or try lifting the vent by hand in the problem areas to see if it is secure?