What Is Roof Flashing?

What Is Roof Flashing?

By Angelina Zhuravleva  •  November 29, 2022  •  3 min
What Is Roof Flashing?

Roof flashing is a thin material used by professional roofers to direct water away from critical areas of the roof. Flashing surrounds roof features like vents, chimneys, and skylights. It prevents water and other elements from entering the roof system and damaging the building by creating a waterproof barrier at these vulnerable points. It also helps to extend the life of your roofing system.

Roof flashing is a vital part of the roofing system and should be installed by a qualified contractor.

In this article, we'll take a closer look at roof flashing and explain its importance in protecting your home from water damage.

What is Step Flashing?

Roofers use various installation methods, but step flashing is the most common. It is created by installing metal flashing on the vertical surface and then overlapping it with another piece of flashing installed on the roof. This overlapping creates a 'step' that funnels water down and away from the critical area.

The purpose of step flashing is to prevent water from running across the top of the shingles and toward the house. This helps keep water from leaking into the home by directing it to the next piece of flashing.

What Is the Purpose of Roof Flashing?

A flashing installed on the edge of the roof directs water into a gutter.

Roof flashing is used to direct water away from the side of a roof. Water should run down the flashing side and be directed to the shingles instead of the roof deck. The purpose of roof flashing is to create a barrier that will stop water from traveling down the roof's surface and entering the building. Flashing surrounds roof features, such as vents, chimneys, and skylights, and it's an integral part of any roofing project.

What Are the Different Types of Roof Flashing?

New plain red clay roofing tiles and flashing on a pitched roof

There are different roof flashing types, each designed for a specific roof part. They include:

  • Continuous flashing is also known as "apron flashing" because it acts much like an apron. It's a long, single metal that carries water down to the shingles below. Long pieces of continuous flashing have built-in expansion joints to move with the home.
  • Chimneys require two pieces of flashing, called base flashing. This ensures that rain always meets a flashing surface that directs it downwards. When the materials expand and contract with the weather changes, the two pieces can move, so the system stays secure.
  • Counter-flashing is a flashing opposite to the base flashing or above the base flashing. This completes the two-part flashing team.
  • Step flashing is a piece of thin metal slipped between every shingle.
  • Sometimes a skylight manufacturer doesn't include flashing as part of their product. In that case, roofing professionals must create or purchase skylight flashing separately.
  • Valley flashing protects this critical area of the roof.
  • Drip edges are thin metal flashing to help water drip off without damaging the home or causing a leak.
  • Kickout flashing bridges the gap between the step flashing and the gutter and directs water away from the wall into the gutter.

Metal Roof Flashing

Red metal roof with brick chimney and base flashing

Metal roof flashing can be made from aluminum, steel, or copper. Contractors often use prefinished steel if they need a long flashing on a wall. It's more rigid than aluminum yet has good corrosion resistance. If they want to do a long run of flashing on a curved surface like around the eaves of a building, they use copper because it's more flexible than aluminum or steel. It will last longer than either material, but it's more expensive than aluminum or steel.

Please read this article to learn how to measure your roof and calculate roofing squares.

Directorii: Best Roofing Contractors Near You

Improper roof flashing is one of the most common causes of roof leaks. The improper installation of flashing around the chimney, roof cricket, or dormer can lead to wood rot and even deck collapse. At Directorii, we don't recommend that anyone install a DIY roof. Leave this job to professionals with experience installing all types of roofs and roof flashing.

At Directorii, we provide a list of pre-screened roofers near you who have been state-licensed and certified by leading roofing companies.

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