How To Install Sidewall Flashing On A Metal Roof

Feb 19, 2024

When it comes to protecting your home from the harsh elements of nature, sidewall flashing is a crucial component that shouldn’t be overlooked. Especially in metal roofing systems, proper installation and upkeep of this feature can help prevent water intrusion and subsequent damage, prolonging the lifespan of your roof. This article delves into the purpose of sidewall flashing in metal roofing systems, shedding light on its significance.

The Purpose of Sidewall Flashing

Sidewall flashing serves a critical role in waterproofing your home, acting as a barrier between the roof and walls. Its primary purpose is to effectively direct water away from the interface of the roof and walls, preventing it from seeping into the structure and causing potential damage such as rot, mildew, and mold.

Specifically in metal roofing systems, sidewall flashing is installed at the points where the metal roof meets the side walls of the house. This could be at dormers, chimneys, skylights, or any other structures protruding from the roof. Here, it carries out the important task of sealing the joints and gaps, which are highly susceptible to water infiltration.

In addition to this essential waterproofing role, sidewall flashing also contributes aesthetically to your home. Available in a variety of materials and colors, it can be matched with the existing roof or siding to create a harmonious and appealing exterior.

However, for sidewall flashing to effectively fulfill these roles, it must be correctly installed and properly maintained. Incorrect installation or lack of maintenance can result in water seepage, leading to expensive repairs and potentially compromising the structural integrity of your home.

Understanding the purpose of metal roofing flashing is the first step towards ensuring the longevity and performance of your roof. The following sections will provide further insights into the different types of sidewall flashing, how to choose the right type for your home, and how to maintain it effectively for optimum protection.

Remember, a well-protected roof translates to a well-protected home. Investing in quality sidewall flashing and giving it the attention it deserves can save you from future headaches and costly repairs.

The Different Types of Sidewall Flashing

In the realm of roofing flashing, there are several types of sidewall flashing that homeowners can opt for. Each of these types varies in their material composition, durability, and aesthetic appeal. Knowing the different types and their advantages can help you make an informed decision when it comes to protecting your home.

Aluminum Flashing

Aluminum flashing is a popular choice among homeowners due to its affordability and ease of installation. It’s lightweight and can be easily shaped to fit any area in need of flashing. However, if you’re residing in a region where severe weather conditions are common, aluminum flashing may not be the best option as it may not withstand extreme weather conditions.

Copper Flashing

If you’re looking for a more durable and aesthetically pleasing option, copper flashing is the way to go. This type of metal roof flashing is exceptionally resistant to corrosion, making it an ideal choice for those living in coastal areas. Keep in mind that copper flashing is more expensive than aluminum and other common types of flashing.

Galvanized Steel Flashing

Galvanized steel flashing is a great option for those looking for durability at a reasonable price. This type of metal roofing flashing is coated with a layer of zinc, which adds to its resistance against rust and corrosion. However, the cutting and bending process of galvanized steel flashing might be a bit challenging due to its thickness.

Lead Flashing

Lead flashing is known for being extremely long-lasting and capable of withstanding the harshest of weather conditions. However, it’s important to note that while lead is highly durable, it can pose serious health risks if not handled properly, especially during the installation process.

Zinc Flashing

A lesser-known yet highly effective option for sidewall flashing is zinc. It is incredibly resistant to corrosion and has a self-healing property which means that minor scratches or damages can fix themselves over time. However, zinc flashing can be difficult to install due to its rigidity.

In conclusion, when it comes to choosing the right type of sidewall flashing, consider factors such as your budget, the climate of your region, and the design of your house. Make sure to consult with a professional roofer to ensure you choose the best option that suits your needs.

How to Choose the Right Sidewall Flashing

Choosing the right sidewall flashing for your metal roof is crucial to ensure its longevity and reduce the risk of water damage. A multitude of factors come into play when making this decision, including the type of metal roofing, the climate, and your budget. Here are some steps to guide you through the process:

Understand Your Roof Type

Before choosing your metal roofing flashing, it’s important to understand the type of roofing you have. Some roofs may require specific types of flashing due to their shape or material. For instance, copper roofs often pair well with copper flashing, as these materials expand and contract at the same rate.

Consider the Climate

Your local climate is another essential factor in choosing the right roofing flashing. Areas with heavy rain or snow require durable and waterproof flashing to prevent leaks. In contrast, in regions with strong sunlight, UV-resistant flashing would be ideal to avoid material degradation.

Consider Your Budget

While it’s vital to select high-quality flashing for your metal roof, you also need to consider your budget. Higher-end materials like copper or stainless steel provide excellent durability but come at a higher cost. On the other hand, aluminum or galvanized steel flashing can be a cost-effective alternative with decent longevity.

Evaluate Flashing Profiles

Finally, evaluate the different profiles of sidewall flashing available. These profiles include L-shaped, step, and continuous flashing. The choice largely depends on the architecture of your house and the roofing system. An experienced roofer can guide you in selecting the most suitable profile for your roof.

Choosing the right sidewall flashing for your metal roof flashing requires careful consideration of various factors. By understanding your roof type, considering the climate, weighing your budget, and evaluating flashing profiles, you can make an informed decision that ensures the long-term performance of your roof.

Take Professional Help

When in doubt, don’t hesitate to seek professional advice. Roofers with experience in metal roofs can provide valuable insight and suggestions. Their knowledge can save you from costly repairs in the future and ensure you choose the most suitable sidewall flashing for your metal roof.

How to Install Sidewall Flashing

Installing sidewall flashing can seem daunting, but with the right steps, it can be a manageable task. Here’s how to do it.

Gather Your Materials

Firstly, you’ll need your metal roofing flashing, a measuring tape, a pencil, metal snips, a drill, and roofing sealant. It’s crucial to choose high-quality metal roof flashing material for longevity and effective protection against water damage.

Taking Measurements

Start by measuring the length of your sidewall. Be sure to add a few extra inches to each side to ensure full coverage. Use your pencil to mark these measurements on your roofing flashing.

Cutting and Bending the Flashing

Using your metal snips, cut the flashing to the appropriate length. After cutting, bend the flashing into an L-shape. One side of the L-shape will be against the wall while the other will lay flat on the roof.

Installing the Flashing

Position your newly cut and bent flashing against the sidewall, ensuring it extends a couple of inches beyond the roof edge. Drill holes through the flashing into the sidewall and secure with screws. Apply roofing sealant to the seam where the flashing meets the wall to create a watertight seal.

Adding the Counter Flashing

For added water protection, consider installing a counter flashing. This is a piece of metal that covers the top of the sidewall flashing. It’s bent at a 90-degree angle, installed into a cut in the sidewall, and sealed with sealant. This directs water away from the seam and onto the roof.

Remember, installing sidewall metal roofing flashing is vital for protecting your home against water damage. Take your time, follow the steps carefully, and you’ll be successful in your installation.

What to Do If You Have a Leak

If you have discovered a leak in your home, it’s important to address it swiftly to prevent further damage. Leaks can lead to pest infestations, mold, structural damage, and other costly problems. Here’s what you can do if you suspect a leak in your metal roofing flashing:

Identify the Source

Start by identifying the source of the leak. Remember, water tends to travel before it drips down visibly, so the actual leak may be located somewhere other than where you see water. Check your sidewall flashing as it’s a common place for leaks to occur in metal roofs. Look for signs of rust, cracks, or gaps in the flashing.

Temporary Solutions

If you have identified the source to be a leaking sidewall flashing, you can apply a temporary solution until professional help arrives. Use a sealant or patch to cover the leak. However, remember that these solutions are temporary and not meant to be long-term fixes.

Contact a Professional

Once you have managed a temporary fix, it’s important to get in touch with a roofing professional. They can assess the damage and provide a permanent solution. Whether it’s a simple repair or a complete replacement of your metal roof flashing, a professional can ensure it’s done correctly and safely.

Prevent Future Leaks

After addressing the current leak, it’s important to take steps to prevent future leaks. Regular inspection and maintenance of your metal roofing flashing can help in early detection of potential issues. Ensure the sidewall flashing is properly installed, as improper installation is often the main cause of leaks.

In summary, leaks in metal roofing flashing should never be ignored. Start by identifying the source of the leak, apply a temporary solution, contact a professional for a permanent fix, and take preventive measures to avoid future leaks. Remember, the health of your roof is critical to the overall health of your house.

FAQs About Leaks in Metal Roof Flashing

Can I fix a leak in my metal roof flashing by myself?

While minor leaks can potentially be fixed with a patch or sealant, it’s always best to contact a professional to ensure the job is done properly and safely.

How can I prevent leaks in my metal roof flashing?

Regular inspection and maintenance of your metal roof and its flashing can help prevent leaks. Also, making sure the flashing is installed correctly in the first place can prevent many issues.

Tips for Maintaining Sidewall Flashing

Ensuring that your sidewall flashing is well-maintained is crucial as it protects the roof’s vulnerable areas from water penetration. Here are some handy tips to help you manage the upkeep of your metal roofing flashing.


Regular inspection is the best way to notice any signs of wear and tear. Make sure to check the areas where your roof meets with walls, chimneys, vents or any other adjoining surfaces. Look out for corrosion, holes, gaps, or loosened sections. Early detection can prevent minor damages from escalating into major leaks.


Keeping the metal roof flashing free from debris augments its lifespan. Accumulated leaves, branches, and other debris may hold moisture and prompt corrosion over time. It’s also essential to remove any mold or algae growth as they can cause the flashing to deteriorate at a faster rate.


Ensure that all the seams and joints are adequately sealed. If you notice any gaps or cracks, use a high-quality sealant to fill them. This helps to ward off water ingress and maintain the integrity of the sidewall flashing.


Applying a coat of paint specifically designed for metal roofs can provide an extra layer of protection. It not only prevents corrosion but also enhances the aesthetic appeal of your roof.

Professional Help

While it’s possible to perform the maintenance tasks yourself, remember that working on a roof can be quite risky. Therefore, it’s advisable to hire a professional roofing contractor, especially for complex tasks. They will have the necessary expertise to ensure that your roofing flashing is maintained properly.

In essence, the key to a long-lasting and effective sidewall flashing lies in regular maintenance and prompt repair of any detected issues. An investment in the upkeep of your metal roofing flashing is indeed an investment in the longevity of your overall roofing system.

FAQs About Sidewall Flashing

In the world of metal roofing flashing, there are often many questions about sidewall flashing. Here are some of the most commonly asked questions and their corresponding answers:

What is Sidewall Flashing?

Sidewall flashing, also known as step flashing, is a type of metal roof flashing that is installed where the roof and wall intersect. Its primary function is to prevent water from seeping into the building, thereby protecting the interiors from potential water damage.

Why is Sidewall Flashing Important?

Sidewall flashing plays a crucial role in safeguarding your home from water damage. It acts as a barrier that directs water away from the areas where the roof meets the walls, thereby preventing leaks and potential structural damage.

What Materials are Used for Sidewall Flashing?

Sidewall flashing is typically made from durable materials that can withstand extreme weather conditions. Common materials include aluminum, copper, steel, and sometimes plastic or rubber. The choice of material often depends on the type of roof and the local climate.

How Often Should Sidewall Flashing Be Replaced?

Generally, sidewall flashing should be checked for damages and wear at least once a year. If you find any issues, like rusting or cracks, it should be replaced immediately. However, if properly maintained, quality flashing can last for several decades.

Can I Install Sidewall Flashing Myself?

While it’s possible to install sidewall flashing yourself, it can be a complex and time-consuming process. It’s recommended to hire skilled professionals who have experience in this area. Improper installation can result in leaks, which can lead to costly water damage to your home.

What If the Sidewall Flashing Leaks?

If you notice a leak in your sidewall flashing, it’s important to tackle the problem immediately. You should first identify the source of the leak and then either repair or replace the flashing. If needed, seek professional help to ensure the job is done correctly.

Understanding the intricacies of sidewall flashing can help homeowners make better decisions for their homes. As always, when in doubt, it’s best to reach out to a professional to ensure the longevity and safety of your roof.


Understanding the importance of metal roofing flashing, especially sidewall flashing, is crucial for maintaining the integrity of your roof and the overall structure of your home. Properly installed sidewall flashing can effectively divert water, preventing leaks and potential water damage.

By recognizing the different types of sidewall flashing and being able to choose the right one for your particular needs, you’re taking a significant step towards protecting your home. It’s also vital to know the correct installation process and what actions to take if you encounter a leak.

Maintenance is another key factor in ensuring the longevity of your sidewall flashing. Regular check-ups and timely repairs can save you a lot of hassle and prevent expensive renovations.

Lastly, do not hesitate to ask questions if you’re unsure about any aspect of sidewall flashing. Utilize resources such as professionals in the field or online communities that can provide invaluable advice and assistance.

In conclusion, investing time and effort into understanding and maintaining your metal roofing flashing can result in a durable, leak-proof roof that will serve you for many years to come.

Big G Roofing