Call Us Today

What Is Flashing on a Roof?

A shingle roof has many components that work together to create a high-performance system that effectively shields a home's interior from the elements. Though many property owners know about shingles, flashing on a roof is equally important to the roofing system. So, what is flashing on a roof, and what does it do?

As Marietta's top-notch roof repair experts, Georgia Roof Advisors consistently deals with different types of roof flashing. As a result, their professional roofers know all about roof flashing, its purpose, and its common problems. Below, their team shares everything you should know about this essential roofing component.

What's Roof Flashing?

If you're asking, "What is flashing on a roof?" you're not alone. Roof flashing is a thin strip of metal that roofers install on shingle roofs to help divert water away from specific areas. You're likely to find metal flashing on parts of the roof where the shingles touch another structure like a skylight or roof valley.

Is Roof Flashing Necessary?

The purpose of installing flashing on a roof is to prevent water from seeping through the roof's most vulnerable points like its seams, edges, and joints. Instead of rainwater soaking these vulnerable spots and causing moisture damage to the roofing materials, underlayment, and the home's interior, the flashing keeps the water out. 

Roof flashing is one of the most important parts of a roofing system since it protects its structural integrity and shields against water damage. When roofers install these thin metal strips on shingle roofs, they often include them under the shingles and over the roof underlayment. Flashing also helps protect metal roofs by sitting on top of the roof panels in critical areas. 

Common Types of Roof Flashing

There is more than one type of roof flashing. A roofing contractor will install the appropriate kind depending on the roof structure, layout, and protrusions. The most common varieties include:

  • Apron Roof Flashing: This L-shaped metal strip usually fits around a wall, dormer, or roof penetration to keep water out of roofing systems and windows. 
  • Counter Flashing: Counter flashing materials also fit along walls, but they're also suitable for sealing chimneys. They're ideal for preventing water from getting behind a roof's headwall.
  • Roof Valley Flashing: When two sloped roof planes touch, they create a valley that needs valley flashing to protect the seam from leaks.
  • Chimney Flashing: As the name suggests, chimney flashing creates a waterproof seal around the space where a chimney and roof meet to prevent water damage to the chimney.
  • Base Flashing: With base flashing, a roofer will install the metal strip where a vertical protrusion and a roof plane meet. Usually, base flashing needs additional metal strips to go on top of it since the two original pieces don't connect.
  • Continuous Flashing: A long metal strip along a roof where a vertical wall sits is called continuous flashing. It's effective at directing water away from weak spots on the roof. 
  • Vent Flashing: Vent flashing or plumbing vent booth flashing is necessary to protect roof vents with a cylindrical shape from water damage. Instead of going over the shingles, roofers install this flashing under them to create a slight elevation.
  • Kickout Flashing: Kickout flashing helps prevent water damage to the roof and a home's siding by directing water into the gutters. 

Popular Materials for Flashing on a Roof

Knowing the answer to "What is flashing on a roof?" means understanding that flashing is thin metal that protects homes from some types of roof damage. Still, homes with asphalt roofs can have flashing in different metals including the ones below. 


If your home has a copper roof or other exterior features on your property consisting of copper, you may have this metal as your roof flashing material. The copper flashing will complement those features well and give your property's exterior a cohesive look.


Most properties have galvanized steel flashing. This material is one of the most popular choices for roofing contractors and homeowners because the metal is visually appealing and doesn't detract from a roof's aesthetics. Galvanized steel also has excellent corrosion and rust resistance. 


Another common flashing material is aluminum. It's lighter and more flexible than steel, so it's easy for roofing companies to work with. Yet, this metal needs a special coating to prevent premature degradation due to exposure to salty air or other alkaline substances. 

What to Know About Maintaining Roof Flashing

Like other parts of your roof, the roof flashing will need periodic maintenance to keep the metal strips in excellent shape and prevent water damage. You should regularly inspect the roof and its flashing to ensure the strips don't have rust, corrosion, or other damage. You don't want to ignore this step because the flashing covers some of your roofing system's most vulnerable areas. 

At least once a year, you should schedule a professional roof inspection from a reputable company. The roofing contractor can assess the flashing and make necessary repairs, replacements, or adjustments to ensure the flashing's ability to perform. 

When to Call the Experts for Flashing Repair or Replacement

It can be confusing to know when you should contact a professional for help with roof flashing if you're unsure what to look for. If you notice any of these signs, it may be time to contact a qualified contractor for a roof inspection and flashing repair:

  • Warped flashing
  • Roof leak
  • Interior water damage
  • Loose flashing
  • Missing nails 
  • Holes or rust in flashing
  • Dried out or missing sealant

Trust Marietta's Roofing Experts for Your Roof Repair Needs

Now that you know the answer to "What is flashing on a roof?" turn to Georgia Roof Advisors. As one of the top roofing contractors serving residential and commercial customers in Marietta, Georgia, their roofing professionals have the expertise, training, and equipment to service all types of roofs. With more than 15 years of industry experience, they can repair roof leaks, install flashing, replace roofing systems, and more.

Georgia Roof Advisors' licensed and insured roofing technicians always use the highest quality products and industry-leading techniques to provide outstanding services. Experience them firsthand by contacting them today for a free estimate.

© 2024 Georgia Roof Advisors. All Rights Reserved.
Privacy Policy
Privacy Policy
Georgia Roof Advisor Payment Logo