Which metal is NOT listed as a corrosion-resistant material for roof valley linings?

Stainless steel is indeed recognized for its corrosion resistance and is commonly used in various applications, including roofing, due to its durability and ability to withstand corrosive environments. The question specifically asks for a metal that is not listed as corrosion-resistant for roof valley linings.

Aluminum, galvanized steel, and cold-rolled copper are often used in roofing applications for their resistance to corrosion. Galvanized steel has a protective zinc coating that prevents rust, while aluminum naturally forms a protective oxide layer. Cold-rolled copper is known for its ability to oxidize and develop a patina, which also offers a level of protection against further corrosion.

In contrast, stainless steel stands out as an appropriate choice for areas that require resistance to corrosion, especially in harsh conditions, making it a suitable material choice for roof valley linings. Thus, selecting stainless steel as not being a corrosion-resistant material is inconsistent with its recognized properties and applications in the industry.