Flashing is the metal or plastic covering that is placed on locations of your roof where two surfaces meet, in order to keep water from seeping through your roof and into your home, where it can cause mold growth and water damage. Flashing is most commonly made out of aluminum (due to its natural anti-corrosive qualities), but it also comes in a wide variety of different materials. Understanding what the different types of flashing are and where they are located can help make roof maintenance much easier.
Valley flashing is the flashing that is installed where two planes of a roof meet each other, forming a spout that will carry water down to the gutter system where it can be removed from the roof. Valley flashing is extremely important, as it works as a channel to carry water. If it begins to degrade, water will very quickly enter your home, and your gutter system may not be able to carry out its function efficiently. Valley flashing is usually installed underneath the shingle layer, so that roof maintenance and replacement will not remove the flashing as well.
Vent Pipe Flashing
Vent pipe flashing is designed to fit directly over flues and pipes, which require circular instead of straight flashing. This type of flashing is cone shaped, and has a base that is neither underneath nor below the shingles of your home, but rather acts as a shingle itself. This means that the shingles are simply cut away to make way for the vent pipe flashing, and it is integrated into the roofing layer.
Drip edges are somewhat different from other types of flashing, and are installed on the edges of your roof, along the eaves. They extend outwards away from the roof, over the gutters or the sides of your home, to prevent water from getting between the fascia boards and inside your home. They are found around the entirety of your roof. Like valley flashing, they are installed underneath the shingles so that the roof can be repaired or replaced without removing the flashing.
Step flashing is the flashing that goes around the sides of a dormer, chimney, or any other installation that extends out of your roof. It sits at a right angle, flush to the side of the installation and the roof at the same time, and is usually sealed with roofing nails and cement to ensure water cannot get beneath it. Step flashing is usually installed over the shingles, as it has to be replaced much more often than valley flashing or drip edges.
Contact a local roofer, like Absolute Roofing, if you have questions or concerns about your flashing.