Flashing are pieces of metal or roll roofing used to prevent seepage of water into a building around any intersection, projection or termination point on a roof, such as vent pipes, chimneys, adjoining walls, dormers and valleys.

When there is a crack in the flashing or sealant has deteriorated due to UV rays, or severe weather wearing, water will leak into those areas and eventually cause a leak. An undetected leak in attics and behind walls may damage the structure of your walls and insulation.