I did an inspection of a 2/12 roof today with my thermal camera and moisture meters. The current owner found 4 leaks, and I found 6 or so places of water intrusion.
The roof coverings are owens corning 50 yr with Sure-nail. They put ice guard on entire roof surface before shingle installation according to manufacturers installation. Entire roof replaced in Sept 07. Previous roof was old 3-tab that never leaked.
The problem appears to be the water is going under the shingles, due to low slope, and running into nail space to drain onto sheathing.
Has anyone seen this issue before?