What Is Roof Flashing and What to Expect from It

a part of a house's roof with pieces of metal on it

The roof of a house has to endure a lot. External factors such as pollution, debris impact, ultraviolet rays and weather conditions are constantly causing strain on it. Roofs need to be strong and resistant because they are a house’s main protection against the environment. Without a doubt, one of the most important forms of roof protection is roof flashing. The main purpose of this procedure is to avoid water seeping in through joints and other openings. It is a versatile technique, one that can shape roof flashing in a specific way. So, you will be able to use it in various areas of a house, including crevices and other hard-to-reach spots.

What Is Roof Flashing?

Roof flashing refers to the installation of thin pieces of metal over joints and other openings. Its objective is to prevent the passage of water by forming a barrier that’s impervious to external conditions. One can also do roof flashing as a part of a weather resistant barrier system. It is used to weatherproof obstacles such as window and door openings, chimneys, vent pipes and roof-to-wall connections. Apart from prolonging a building’s life, roof flashing helps reduce mold problems. Metal roof flashing uses materials such as lead, zinc alloy, aluminum, copper and stainless steel. A roofer can also flash a roof can using synthetic products such as rubberized asphalt, butyl rubber, and acrylic.

Depending on the area of the roof where it’s applied and its overall purpose, flashing can have different shapes. Some of the most common are:

Deflective roof flashing: This term is used when flashing is placed around discontinuities to deflect water away from seams.

Roof penetration flashing: Usually made from stainless steel, this type of roof flashing is used to waterproof protrusions, pipes, cables and supports.

Chimney flashing: Used to prevent leaks around the chimney.

Pros and Cons of Roof Flashing

a roof flashing around a chimney


It’s a long-lasting, semi-permanent solution: Roof flashing is a building technique that has been around for over two centuries. Amazingly, there are houses over 100 years old that still have their original roof flashing. Because it’s made of solid metals that are impervious to exterior elements, roof flashing is extremely durable. Although there are occasions when roof flashing repair is needed, it does not happen too often.

You can either expose or conceal it: Visually, flashing constitutes a subtle addition to the overall look of the roof. It usually contains sheet metal, allowing different colors and textures depending on the type of metal used. The metal can cause a type of reflection that can sometimes be bothering.

Despite the subtlety of exposed flashing on roofs, some people choose to use concealed flashing. Hidden beneath shingles and structural components of a roof, concealed flashing is made of either sheet metal or a waterproofing membrane. Depending on the type of structure, membranes can consist of bituminous coal or plastic. Also depending on structural circumstances, concealed flashing may be rigid or flexible.

It doesn’t just prevent leaks: Although the main objective of roofing flashing is to prevent water from getting in, it keeps other unwanted substances out as well. By avoiding moisture, it eliminates the possibility of mold invading the home. At the same time, it prevents insects from getting inside the structure and causing damage.


A proper flashing is not easy to install: In order to work properly, roof flashing needs to be executed with extreme precision. After a placing strategy has been developed, the flashing needs to be constructed especially for each home. Unfortunately, a flawed installation can lead to even bigger problems in the near future, including water seepage, mold, leaks and even structural damage. For that reason, we highly recommend you to seek professional help to install roof flashing.

It can get expensive: Depending on the type of installation and the material chosen for it, roof flashing can get costly. Although the materials themselves are not terribly expensive, a proper installation requires the kind of expertise only professionals can offer. On average, each separate addition of roof flashing may cost between 250 and 500 dollars. However, professional help ensures a guaranteed, long-lasting roof flashing installation.

What to Expect from Roof Flashing

a close-up of a roof vent flashing

As we mentioned before, roof flashing is not a quick and easy process. In order to guarantee proper functioning, one must plan this process in a precisely way and execute it by hiring experienced professionals. However, despite any difficulties flashing may pose, the results will surely improve your quality of life. Even though it may not seem that way, leakage-related problems can cause terrible emotional and financial distress. At the same time, there’s nothing quite as reassuring as knowing you are safe and sound in your own home. It’s important to keep in mind that a house’s roof is its main defense against the environment.

Once you installed roof flashing, you can expect all water seeping and leakage to halt. Assuming there is no serious damage to the structure of the house, some cleaning and drying should leave everything looking as good as new. Related problems such as mold and general dampness should also disappear very quickly. Because impervious and resistant materials are its main components, roof flashing usually lasts a long time. If the roofing contractors did the flashing properly, maintenance and repairs should be sparse. Take into account that more specialized procedures such as roof to wall flashing may take longer and be more demanding.

Final Words

We can conclude that roof flashing is an indispensable part of any good roof. Although it may seem like a detail, flashing is actually a vital component of a roof’s integrity. It serves the important function of preventing water from damaging the integrity of a home. Additionally, it provides an extra layer of protection that makes a home an even safer and more secure environment. However, it’s not the kind of home improvement people without experience can do by themselves. Because it demands serious planning, a congruent strategy and precise executing, only licensed professional should do roof flashing.

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