When flashing is of aluminum zinc coated steel, the minimum thickness shall be what value in inches?

• A. 0.0150
• B. 0.0179
• C. 0.0200
• D. 0.0250

Answer: (B)

The important point is choosing a thickness that will hold up when forming and sealing flashing without tearing or denting. Aluminum-zinc coated steel is used for its good corrosion resistance, but for flashing you still need enough metal to bend neatly over edges, resist puncture from fasteners, and maintain a watertight seam under weather conditions. The standard minimum thickness for this material is 0.0179 inches, which matches the common 26-gauge size used in roofing practice. This thickness provides a reliable balance of strength and workability. Thinner thickness would risk tearing or denting, while thicker options aren’t typically required for standard flashing and would add unnecessary cost.