https://blogfreely.net/staydryroof/2o3fu8cnw2">https://blogfreely.net/staydryroof/2o3fu8cnw2. A quality roof will have them installed throughout the edge of the roofline, where vertical walls satisfy the roof incline, https://lewisrwyy956333.blogoscience.com/46150318/stay-dry-roofing-truths