What roof valley means
A valley is the inside angle where two roof slopes meet. It carries more water than any other part of the roof, so it gets its own lining under the shingles or metal.
Also called valley.
Where it matters on a roofing job
Valleys are cut open, woven or lined with metal, and the method changes the labor and the look. Write the valley method into the estimate. On measurements, valleys add waste because every shingle that meets one gets cut.
What the model code says
- Valley linings go in before the shingles, following the manufacturer's instructions. (IRC 2021, Chapter 9)
Check which code edition your building department enforces for roof valley before you quote.
What it costs
Koira's roof repair cost guide puts a typical job at $1,100, with most between $390 to $1,850. The guide shows its sources and what moves the price. The roofing materials calculator prices a job line by line.
Work it out
- Free calculator: Roofing materials calculator
- Cost guide: Roof repair cost
- Licensing: Roofing license rules by state
- Tools, templates and guides: Free roofing resources
Sources: 2021 International Residential Code, Chapter 9, Roof Assemblies (ICC). Checked October 9, 2026.