Since the house was raised more than four inches (20cm), and the lean-to (rear entrance add-on) was rebuilt and raised at a different time, the roof line where it was sealed to the house was compromised. The shingles buckled, and leaks occurred in heavy rains. I cut the shingles to the correct shape and sealed it with roofing tar. Ugly but sufficient.
Health issues and wind prevented me from doing more this day.