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What Is Roof Flashing?  What Are The Different Types Of Roof Flashing?

Posted on : January 24, 2023

What Is Roof Flashing?  What Are The Different Types Of Roof Flashing?

Are you tired of leaks in your roof? The solution lies in understanding roof flashing and the different types of flashing available. As roof flashing helps deviate the flow of water that may leak through gaps, cracks, and holes, installing them can increase the lifespan of your roof. 

If you are considering a new roof installation or replacement, you must install roof flashing to it to prevent unwanted water leaks. In the blog, we have provided an in-depth discussion on roof flashing, its different types, and the installation process. Read till the end to decide what type of flashing would be best for your roof. 

What Is Roof Flashing? 

Sections on your roof where the roof intersects with walls, chimneys, vents, and skylights on your roof leave gaps for water penetration. Those gaps, if left uncovered,  become a cause for water leakage through the roof.  Not to mention, the water that gets through the holes and cracks in the roof decreases its lifespan and affects its durability. 

Therefore, roof flashing is the best option to rely on to fill and cover gaps made by these intersecting points. Made of different materials, including copper, stainless and galvanized steel, lead, and rubber, roof flashing benefits you in the long run.  Based on the purposes they are made to serve, each type of roof flashing comes in various shapes and sizes. 

To have a better understanding of roof flashing, read our next sections in the blog, explaining the functions and types of roof flashing available. 

How Does Roof Flashing Protect Your Roof? 

Roof flashing is an essential element of any roofing system that aims to safeguard the most vulnerable areas of your roof from water damage. Typically made from metal or rubber, it is installed where the roof deck meets vertical surfaces, such as chimneys, skylights, or walls. 

In addition, flashing serves as a barrier to divert water from areas where the chance of water infiltration is high, helps to prevent ice dam formation during the winter months, and keeps the wind out. Thus it avoids the problem of water infiltrating the attic. 

Regular inspections and maintenance are crucial to ensure the flashing is operating effectively and prevent costly repairs in the future.

Where Is Roof Flashing Installed On A Roof? 

Roof flashing is typically installed in areas where the roof deck meets a vertical surface, such as:

  • At the base of a chimney
  • Around skylights
  • Along the edges of a dormer
  • At the intersection of a wall and the roof
  • At the intersection of a valley and the roof
  • Around pipes or other penetrations through the roof
  • At the edge of the roof where it meets a gutter
  • Along the perimeter of the roof where it meets the wall of the building

It's worth noting that the specific location of flashings depends on the construction of the building, the design of the roof, and the local building codes so some other locations could be used depending on the specific case.

Benefits Of Installing Roof Flashing

There are several benefits of installing roof flashing on a roof, which we have highlighted below. 

1. Prevents Water Damage

Roof flashing prevents water damage by acting as a barrier that redirects water away from areas where the roof deck meets vertical surfaces. The flashing is designed to be installed in a way that creates a tight seal, so that water doesn’t penetrate the barrier. Additionally, flashing covers any gaps or joints in the roofing system, which prevents water infiltration. 

2. Prevents Ice Dams

Ice dams form when snow and ice on the peak of the roof melt and the water runs down to the eaves and gutters but then refreezes.  The cycle of melting and refreezing creates a dam that prevents further meltwater from flowing off the roof. 

Roof flashing helps to prevent the formation of ice dams by preventing air leaks in the sections where the roof comes in contact with any walls, pipes, vents, or other projections. This way they help aid in keeping the roof at a singular temperature 

3. Improves The Look Of The Roof 

Roof flashing can increase the roof's look by hiding unsightly penetrations such as pipes, vents, and other roof projections. 

You can paint or coat the flashing to match the color of the roof and blend seamlessly with the surrounding shingles. This will improve the overall appearance of a roof, making it look more polished and well-maintained.

4. Extends Longevity

Roof flashing increases the roof's lifespan by preventing water damage, which can cause the roof to deteriorate over time. 

Water infiltration damages the roofing system and the interior of the home, as well as creates safety hazards such as mold growth. By preventing water damage, flashing can increase the lifespan of the roof and save homeowners from costly repairs or replacements in the future.

Materials Used For Roof Flashing

The type of flashing on a roof can differ based on the materials used. Here is a list of all the materials used to form roof flashing. 


Copper is a heavy-duty material used for roof flashing for its resistance to corrosion and longevity. For flashing around chimneys and other high-end roof penetrations, like on historical or high-end buildings, copper is the best choice. 

Additionally, its fire resistance properties make it a popular choice for use around chimneys.

It is worth keeping in mind that copper flashing eventually develops a patina over time, giving it a characteristic greenish color. The formation of a patina on copper flashing results from many chemical reactions with the environment, but a patina is not considered a defect. 


Aluminum is a common material used for roof flashing because it is lightweight, durable, and resistant to corrosion. In addition, it is available in a variety of thicknesses, widths, and lengths to fit the specific needs of a project. 

Additionally, aluminum flashing is available in different types, such as roll-formed aluminum and extrusions, depending on the specific application and local building codes. Roll-formed aluminum is a cost-effective option that is suitable for many applications and is easy to install.

Stainless steel

One of the properties of stainless steel that sets it apart from other types of flashing is its ability to withstand high temperatures. Made up of a combination of iron, chromium, and other alloys, stainless steel is resistant to heat and can maintain its strength and properties even in extreme temperatures. 

This makes it particularly useful as flashing in high-heat areas, such as around furnace flues or in industrial settings where temperatures can get relatively high. Other materials, such as aluminum or copper, may warp, bend or even melt under the same conditions.

Galvanized Steel

Galvanized steel is used for roof flashing due to its durability and resistance to rust and corrosion. This is achieved by coating regular steel with a layer of zinc, which protects the steel from the elements. Moreover, It is often used to protect vulnerable areas of a roof, such as pipes and other roof penetrations. 

Galvanized steel is one of the best options for flashing as it is available in different sizes to fit the specific needs of a project. One of the key benefits of using galvanized steel flashing is its cost-effectiveness and durability. It is a budget-friendly option that you can use for various applications.


Did you know that lead has been used as a flashing material for hundreds of years? The material is soft and pliable, making it easy to shape and mold to fit any roof contour. In addition to its flexibility to bend and reshape, lead flashing is knowns for its fire resistance and corrosion-free properties. Though commonly known as a toxic material, lead flashing is used to seal and protect the areas of the roof that are vulnerable to water damage. On your roof, this material is completely safe since you are not touching it, or breathing in its fumes. 


Rubber flashing is a versatile and durable material used to seal and protect areas vulnerable to water damage. Made from synthetic rubber such as EPDM or neoprene, it can withstand exposure to UV rays, the atmosphere, and extreme temperatures. This makes it a suitable option for areas that are frequently exposed to moisture or salt spray. 

Roof Flashing
Roof Flashing

Different Types Of Roof Flashing

To serve different purposes, there are different types of roof flashing available. Some are as follows: 

Step Flashing

This is a type of flashing used on roofs where the roof meets a vertical surface such as a chimney or wall. It is installed in a "step" pattern, with each piece bent at 90 degrees, and overlapping the previous piece below it.

Step flashing is an important component of a roofing system, as it helps to prevent water infiltration around the vertical surfaces, and is a type of flashing that can go behind other roofing materials. 

Counter Flashing

Counter flashing covers the top edge of step flashing and is typically made from metal or rubber. The purpose of counter flashing is to provide an additional layer of protection against water infiltration around vertical surfaces such as chimneys, walls, and skylights.

Chimney Flashing

Chimney flashing is a material used to seal the area where a chimney meets the roof. It is generally made of metal, such as aluminum or copper, and is used to prevent water from leaking into the home through the chimney. 

Valley Flashing

Valley flashing seals the area where two roof planes meet, forming a valley between them. Roof valleys are common areas where leaks occur, as water can easily collect there and then seep into the home. Valley flashing is made of aluminum or copper and is used to direct water away from the valley and into the gutter system.

Factors To Consider When Choosing Roof Flashing Materials

Before you purchase any flashing materials for your roof, you must consider the factors that affect its longevity and durability. 

Climate And Weather Conditions

The type of roof flashing material you choose will depend on your project’s location and climate. If you live in a humid area, look for materials that stand up well to moisture, such as copper. In dry areas, aluminum is the better choice. An expert can help you decide what is best for your project based on the existing conditions and expected weather patterns.

Durability And Corrosion Resistance

When selecting roof flashing materials, durability and resistance to corrosion are important considerations. The roof flashing should be able to withstand extreme weather conditions and resist damage from ice, water, and debris.

Cost And Availability

Cost and availability are always a big consideration when choosing a material. The more familiar you are with specific products, the easier it is to find out if one will cost more than another option.

Roof Flashing Installation Process

The proper installation of roof flashing is an important step in protecting your home from water damage.

  • Measure the areas on the roof where flashing is needed, such as around vents, chimneys, and skylights.
  • Remove the old flashing and clean the area to ensure a smooth surface for the new flashing.
  • Cut the new flashing to size and bend it to fit the roof's contours.
  • Securely nail or screw the flashing into place, ensuring a tight seal.
  • Apply a waterproof sealant to the edges of the flashing for an additional layer of protection.
  • Inspect and ensure correct installation of flashing for effective protection from water damage.

To keep your flashing in good condition and make sure it doesn’t develop rust, corrosion, mold, or mildew, it is important to paint and maintain it in a timely manner. Maintenance and regular upkeep can extend the lifespan of roof flashing, and increase its durability. 

If you are planning to replace your roof, read our blog on why should you replace your roof before it's too late.

Best Roofing Company In Pittsburgh

Roof flashing is an important aspect to consider when installing and replacing roofs. Particularly, when you live in storm-prone areas where the chances of roof damage is high. 

To conclude, you could say roof flashing is the key that helps keep your roof safe and increases its longevity and durability. The gaps between your roof deck and the intersections around walls, chimneys, or other protrusions, if left open, can become a serious cause of roof damage.

Considering all the factors mentioned above, if you want to install top-quality roof flashing during a roof replacement in Pittsburgh, McClellands Contracting and Roofing, LLC is a great choice as your chosen contractor. 
We are a team of professional roofers serving residents and business owners with our roof installation and replacement services. Call us today at (412) 206-6718 for a quick consultation.

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