What flashing means
Flashing is thin sheet metal or membrane worked into a roof or wall wherever the surface is broken: at walls, chimneys, valleys, skylights and pipes. Its job is to turn water back out onto the roof or wall face instead of letting it run in behind.
Where it matters on a roofing job
Most roof leaks are flashing leaks, not shingle leaks. When you chase a leak, start at the flashing above the stain. On a reroof estimate, say whether flashing is new, reused or resealed, because that one line is the difference between a warranty you can stand behind and a callback.
What the model code says
- Metal cap flashing must be at least 0.019 inch thick, nominal. (IRC 2021, Chapter 9)
Check which code edition your building department enforces for flashing before you quote.
What it costs
For flashing, the closest koira.ai price is the roof repair cost guide, near $1,100 for a typical job and $390 to $1,850 for most. The guide shows its sources and what moves the price.
Work it out
- 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.