Definition of flashing

The word "flashing" has multiple meanings in different contexts, but in the context of construction, it refers to a thin, narrow strip of waterproof material installed at joints or angles to prevent water from penetrating a building's exterior. The origin of the term "flashing" in this sense can be traced back to the mid-19th century. At that time, roofers and builders used strips of bent or folded sheet metal, known as "suiting," "flashings," or "waterboardings," to divert water away from joints and edges of a building's exterior. The term "flashing" derives from the original process of bending or shaping the sheet metal to fit over a joint or corner, which was sometimes called "flashing up." This technique allowed water to flow smoothly over the joint and prevented it from seeping behind the building's exterior cladding or into the underlying structure. Today, "flashing" is still commonly used in construction to indicate waterproof membranes or materials used to prevent water from entering a building through joints, seams, or angles. Whether made of sheet metal, rubber, or synthetic materials, these flashing components are crucial for preserving a building's structural integrity and preventing water damage.