Your roofing system is not actually seamless. Like other exterior home components, it has vulnerable areas that, when overlooked, can lead to a number of roofing problems. This is where the flashing (or ice and water barrier) comes into play. It refers to the thin, waterproofing material that’s fitted at the joints, edges and breaks along your roof. By keeping these weaker areas sealed, the flashing prevents rainwater from infiltrating the inside of your roof, protecting it from damage.