I had a question that I was hoping I could get some insight into. I'm almost done my roof (finally!!!) and I left some areas unshingled as per my plumbers instructions for roof vents. I want to run a secondary vent out through the lower rear roof in the picture as my kitchen and 1/2 bath are about 30' from the main stack. I was wondering if there are any problems being near the upper overhang? I don't want to be peeling up shingles to put it somewhere else like he's suggesting now as I have about $2500 worth of Grace Ice&Water Shield covering my entire roof. I'll be using Waltite in the roof as well so I don't want to take any chances on a leak. Thanks, Sean