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The Different Types of Roof Flashing and When to Use Them

Roof flashing is an essential component of any roofing system that helps prevent water leakage at vulnerable areas where the roof meets walls, chimneys, skylights, vents, and other roof penetrations. Flashing is designed to direct water away from these critical junctions and protect the underlying structure from potential water damage. In this article, we’ll explore the different types of roof flashing and when to use them to ensure a watertight and durable roofing system.

1. Step Flashing:

Step flashing is commonly used along the intersecting area between a roof and a vertical surface, such as a chimney or sidewall. It consists of small, L-shaped metal pieces that are layered in a “stepped” pattern. Each piece overlaps the one below it, creating a barrier against water intrusion. Step flashing is typically used in conjunction with roofing materials like shingles or tiles.

When to Use Step Flashing: Use step flashing when there are sidewalls, chimneys, dormers, or any vertical structure that intersects the roof. This type of flashing is particularly effective at preventing water from seeping into these vulnerable areas.

2. Continuous Flashing (Counter Flashing):

Continuous flashing, also known as counter flashing, is used to cover and protect the upper edges of step flashing. It is usually made of metal and is custom-fitted to cover and seal the step flashing, creating a continuous barrier against water infiltration.

When to Use Continuous Flashing: Counter flashing is used in combination with step flashing to provide an extra layer of protection at the intersection of the roof and a vertical structure. It is commonly used with brick or stone walls and is especially effective in areas with heavy rain or strong winds.

3. Valley Flashing:

Valley flashing is employed in roof valleys, where two roof planes intersect to form a “V” shape. It is typically made of metal and directs water down the valley to prevent water from pooling and seeping under the roofing materials.

When to Use Valley Flashing: Valley flashing should be used in all roof valleys, as these areas are particularly susceptible to water runoff. Proper installation of valley flashing is crucial to ensure water is efficiently directed away from the roof surface.

4. Vent Pipe Flashing:

Vent pipe flashing is used around vent pipes and other roof penetrations to create a watertight seal. It usually consists of a rubber or metal boot that fits snugly around the vent pipe and is secured to the roof.

When to Use Vent Pipe Flashing: Use vent pipe flashing around any roof penetration, such as plumbing vents, exhaust vents, or chimneys. Properly sealed vent pipe flashing prevents water from seeping into the roof through these openings.

5. Drip Edge Flashing:

Drip edge flashing is typically installed along the edges of the roof to provide a neat finish and to direct water away from the roof’s fascia. It is often made of metal and extends slightly over the edge of the roof.

When to Use Drip Edge Flashing: Drip edge flashing is recommended for all roof edges to protect the fascia board from water damage and prevent water from running down the roof edge and under the roofing materials.


Understanding the different types of roof flashing and their purposes is crucial for maintaining a watertight and durable roofing system. Step flashing and continuous flashing protect intersections between the roof and vertical structures, valley flashing directs water in roof valleys, vent pipe flashing seals roof penetrations, and drip edge flashing protects roof edges and fascia. Proper installation and use of the appropriate flashing materials are essential for preventing water leakage and maintaining the integrity of your roofing system. If you’re unsure about the flashing requirements for your specific roof, it’s best to consult with a professional roofing contractor to ensure the proper application of flashing and protect your home from potential water damage.

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