This actually is a multi-part question but I'll try to keep it short. I've got a gambrel roof that is due for a re-roofing. The last time it was done about 21 years ago, we used dimensional shingles (Timberline) and the roofer said that the shingles that make the bend from the upper pitch to the lower pitch would lay down and seal - which they never completely did on the north side of the house. From what I understand, that's the way to do it with 3-tab shingles which are thinner and bend more easily. So now we are looking for the right way to go (cuz we still don't want 3-tabs). The search led me to drip edge...and that led me to vented drip edge. One roofer strongly advised us not to go with the VDE (vented drip edge) ( I'm getting tired of typing it all out). He says water will find it's way in, especially in the winter. Another is willing to do it, but now I have doubts. So, does this stuff do the job well? And here's the second part of the question. How do I know if I REALLY need VDE? I have a ridge vent at the top of my roof and the attic is dry, so I know the upper portion is vented ok, but I have no way of knowing if the lower portions (mansards?) are vented. They have soffits at the bottom, but I can't tell if they have airflow where they meet the upper roof I'll see if I can find some helpful pictures when i get back home.