Symptoms
- Leak location traces back to where two roof sections meet
- Debris buildup visible in the valley from the ground
- Water stain runs in a line rather than a single spot
Likely causes
- CommonWorn-through valley flashing or shinglesValleys see more water volume than flat roof areas, wearing materials faster.
- CommonDebris damming water in the valleyLeaves and twigs collect in valleys and force water sideways under shingles.
- PossibleIce buildup in the valleyValleys hold snow longer and can form localized ice dams.
What to do
- From the ground, look at the valley for visible debris, moss, or bare spots in the shingles.
- Use a leaf blower or garden hose from a ladder at the eave to clear light debris from the lower part of the valley without climbing onto the roof.
- Check the attic underneath the valley for staining or daylight.
- Note whether the leak only happens in heavy rain, suggesting the valley is overwhelmed, versus any rain, suggesting a hole.
- Trim back overhanging branches that drop debris into the valley.
- Schedule a roof inspection to check the valley material and reline it if it's worn or improperly installed.
- Keep the roof clear of debris going forward, especially before fall and winter.
Tools and parts
- Ladder
- Leaf blower
- Garden hose
When to call a pro
Call a roofer to reline or repair the valley if leaking continues after debris is cleared.
Safety
Use caution
Clear debris from the ground or a ladder rather than walking in the valley, which is often steep and slippery.