Over time, will the 25 ft. 26-Gauge Galvanized Steel Roll Valley Flashing rust?
Here is some information about steel roll valley flashing.
The roll valley flashing has a galvanized finish, which will deter rust. Galvanizing is one of the most widely used to methods for protecting metal from corrosion. The zinc in the galvanization helps to protect the raw steel and when the coating is scratched, zinc will still “sacrifice its anode” easier than the base metal does – which protects it from rusting. Under normal conditions the flashing will typically outlast your shingles.