Flashing for your roof
To understand if roof flashing is necessary, let’s describe what is roof flashing. Roof flashing is a thin strip of metal that is installed around protrusions of the roof like chimneys, dormers, skylights, vents, and where roof changes meet. The purpose of roof flashing installation is to redirect water from these critical areas. 
Roof flashing material is typically a thin galvanized metal. Depending on the roofing material, the architectural style of the house, and the customer’s budget, roof flashing also come in aluminum, copper, lead, stainless steel, and zinc alloy for a home that an architectural metal with a coating is more appropriate. Among those metals are architectural metal roof flashings are metals with a coating such as anodized aluminum, galvanized steel, lead-coated copper, terne-coated copper, galvalume, and metals akin to stone-coated metal.
What are the different types of roof flashing?
Now that you know the types of metal that roof flashing comes in, let’s talk about the different types of flashing and their purpose:
- Apron or Continuous: Apron or continuous flashing is a long piece of metal that takes water to the shingles below it, which is why it is often referred to as apron flashing. It isn’t a flexible piece of metal, so as a roof contracts and expands, this piece of metal sometimes needs replacing.
- Base: A roof with features like a chimney, requires two pieces of flashing. This strip of flashing ensures that rain meets the flashing surface and directs it down. Installation around the chimney can be challenging, and when the roof contracts and expands, it can cause it to come loose.
- Counter: This flashing is installed above or opposite to base flashing, to complete the base flashing.
- Step: This is a rectangular piece with a 90 degrees angle in the center and is used at the wall. There are multiple pieces in the layers of shingles to ensure water is directed down and away from the wall.
- Skylight: Some brands of skylights come with the flashing to fit the product. If the skylight is already installed, a professional roofing contractor can install it separately.
- Valley: A valley is where two roof angles meet, and the metal roof flashing ensures the water is redirected.
- Drip Edges: The drip edge roof flashing is a thin metal that redirects the water off the roof so that it doesn’t damage the house.
- Kickout: This roof flashing creates a bridge between where gutter and step flashing meet.
Does flashing go over or under shingles?
Water is a roof’s enemy, regardless of the structure’s age. Yet this is the one component of a house that is neglected. Roof flashing is installed on top of shingles. Some area, it is layered with the shingles, using step flashing.
Do roofers replace flashing?
Yes, roof flashing is part of the roofing and is installed by the roofer. If you’re needing replacement roof flashing, a general contractor with roofing experience can replace bent, damage, and missing roof flashing.
What does flashing on a roof look like?
A professional roofing contractor that has the experience, they will install the roofing in a way where it blends in with the roofing material. It will be installed so that most of it will not be visible from the street, and what is visible is slight. 
How do you fix roof flashing?
Some roof leaks are where the metal roof flashing is (or isn’t) along the edges, in the valleys, and along junctions around chimneys, dormers, vent pipes, etc. Because a roof contracts and expands with the weather and roof flashing doesn’t, corroded spots or small holes can form that need to be repaired. First, with sandpaper or a wire brush, roughen around the hole then clean it off. Cut a patch larger than the area you’re repairing. Next, apply roofing cement to cover the patch. Corroded or damaged flashing will need to be replaced, which requires removing some of the shingles, some of the mortar, and the damaged flashing. A professional roofing contractor best does this.