Roof Valley Leaking
Address within 1–2 weeks to prevent further damage
Valley leak on your roof? Valleys handle the most water flow and are leak-prone. Learn repair methods ($300–$1,500) and when valley replacement is needed. Estimated repair cost: $300–$1,500. For a precise estimate based on your actual roof, get a free satellite quote at RoofVista.
Likely Causes
Valley flashing corroded, cracked, or displaced from thermal movement
Debris accumulation (leaves, branches) in the valley creates a dam that forces water under shingles
Closed-cut valley installation where shingle overlap has worn thin over time
Ice dam formation concentrated in valleys due to slower drainage
Foot traffic across the valley during maintenance crushing the underlying material
How to Diagnose This Problem
- 1
From the ground, look at valley lines — visible flashing gaps, rust, or lifted shingles indicate trouble
- 2
Check for debris buildup in valleys — clean regularly to prevent damming
- 3
In the attic, trace the valley location and check for water stains along its path
- 4
After rain, check if the valley drains completely or holds standing water
- 5
Check valley type: open (visible metal) vs closed (shingle-covered) — open valleys are easier to diagnose
Estimated Repair Cost
$300 – $1,500
Typical repair range (varies by location and severity)
When to Replace Instead of Repair
If valley leaks are recurring despite repairs, the valley flashing needs full replacement — best done during a re-roof. Valleys are the #1 leak point on any roof and should be installed with ice-and-water shield beneath the flashing.
Materials Affected
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