Which material is known to be used as a protective barrier against moisture in flashing applications?

Metal is widely recognized as an effective material used as a protective barrier against moisture in flashing applications. Its durability, resistance to corrosion, and ability to form a secure seal make it ideal for directing water away from critical areas of a structure, such as roofs, chimneys, and windows. Being impervious to moisture, metal flashing can prevent water infiltration, ultimately protecting the underlying components of the building from damage such as decay, mold, and structural weakness.

Other materials like fiberglass, wood, and plastic, while they may have other useful properties, are not as commonly employed as metal in the context of flashing. Fiberglass can be susceptible to water absorption, wood is prone to rot, and although plastic can be used in some applications, it may not provide the same longevity or effectiveness as metal flashing under varied environmental conditions. Hence, metal is the go-to choice for effective moisture barrier applications in construction.