Select an appropriate valley flashing method (open metal, closed-cut, or woven) for a given shingle product and roof condition.
domain: nrca.net · 5 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
Steps
Review the shingle manufacturer's current installation instructions, since many manufacturers restrict or void warranty coverage for woven valleys on laminate/architectural shingles.
For open metal valleys, confirm metal type/gauge, minimum width, and underlayment/ice-barrier lap requirements per manufacturer instructions and general NRCA guidance.
For closed-cut valleys, confirm the manufacturer's minimum offset nailing distance from the valley centerline and correct layer sequencing (first side run full-width, second side cut back).
Confirm valley underlayment/ice-barrier coverage extends the required distance on each side of the valley centerline per code and manufacturer requirements.
Document the chosen method and rationale (aesthetics, expected water volume, manufacturer restriction) in the job file.
Known gotchas
Woven valleys are frequently disallowed by shingle manufacturers for laminated/architectural shingles even where local custom favors them — check the specific product's install sheet, not general industry habit.
Nail placement too close to the valley centerline in closed-cut valleys is a common cause of leaks; confirm the manufacturer's minimum offset distance rather than using a rule of thumb from a different product line.
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