Roof valleys handle more water than any other area of a sloped roof. When valleys are detailed well, the roof performs. When they’re not, leaks tend to return—even after “patches.”
Valley styles: open vs closed
Open metal valleys
- Pros: sheds water and debris well, easier to inspect, often durable.
- Cons: metal is visible (some homeowners prefer hidden valleys).
Closed-cut valleys
- Pros: clean look with shingles covering the valley line.
- Cons: can trap debris if not maintained; cut line and nail placement matter.
Woven valleys
Woven valleys can work on certain shingle types, but heavy architectural shingles can make weaving bulky and prone to uneven wear.
Why valleys leak
- Nails driven too close to the valley centerline
- Missing or inadequate waterproof membrane beneath the valley
- Debris dams that back up water in storms
- Improper metal overlaps or corrosion
- Cut shingles that don’t lie flat or are poorly sealed
Maintenance tips that prevent valley failures
- Keep valleys clear of leaves and roof grit (especially under trees)
- After storms, look for concentrated debris piles and remove them safely
- Make sure gutters/downspouts can handle valley discharge
- Inspect nearby flashings—valleys often connect to walls or dormers
Repair vs replacement for valley leaks
Some valley leaks can be fixed with targeted detail rebuilds. If the valley is leaking because the roof is broadly worn out, a replacement plan is usually more cost-effective long-term.
Next step
If your leak seems to track along a valley line, use our leak-finding checklist and then schedule an inspection. For fast help, visit roof repair or request an estimate.