What is the recommended condition for adhering metal flashing to bituminous materials in re-roofing applications?

In re-roofing applications, the recommended condition for adhering metal flashing to bituminous materials is primed. Priming prepares the surface of the flashing and enhances adhesion by providing a suitable bonding surface for the bituminous material. This is especially important because bituminous materials have specific properties that can make it challenging for adhesives to bond effectively without proper preparation. A primed surface creates an appropriate texture and chemical compatibility that encourages the adhesive to form a strong bond, ultimately leading to a more durable and long-lasting roofing system.

Primed surfaces help prevent potential issues such as water infiltration or detachment of the flashing, which could lead to further complications in the roofing system. Therefore, proper priming is a critical step in ensuring the performance and longevity of the roof.