Old Gutter Guard Metal Left Under Shingles

Old gutter helmet metal gets left underneath the new shingles. This made the shingles weak and wavy at the edge of the roof.

https://youtu.be/ybxkhbi-pu0

A couple of things here, these edges of the roof get the most abuse. The starter shingles need to glue to the dimensional shingles. Cant happen when the starter shingles are upside down or backward. The metal left from the old gutter guards is also a big problem.