Water is patient and opportunistic — it finds the path of least resistance. The areas most vulnerable on any roof are the transition points, where different materials or surfaces meet:
- Flashing — anywhere metal flashing is used (chimneys, skylights, walls, valleys) is a common leak point, especially as flashing ages, lifts, or was installed incorrectly to begin with
- Valleys — the V-shaped channels where two roof slopes meet concentrate water flow and take more wear than flat field areas
- Pipe penetrations — every pipe or vent that comes through your roof is a potential entry point if the boot or seal around it fails
- Ridge line — particularly if ridge venting was improperly installed or if the cap shingles are aging
- Eaves and gutters — in Montana especially, ice dams form at the eave edge and force water back up under shingles where it was never meant to go
- Skylights — the perimeter seal and flashing around skylights are common culprits, especially on older installations
If you’re seeing water intrusion and aren’t sure where it’s coming from, don’t assume the entry point is directly above where you’re seeing it inside. Water travels. A professional inspection is the most reliable way to trace it to the source.