How to Seal Corner Flashing (and Why it's Important)

How to Seal Corner Flashing (and Why it's Important)

Do you ever get the feeling that your roof is vulnerable? If you do, you must ensure you have excellent flashing like custom flashings.

An example of flashing is corner flashing, a crucial part of a roof that protects the structure. Without corner flashing, roof corners can be vulnerable to leaks and structural damage.

If water leaks through, the rot it causes can cause massive structural damage to the roof and house, which is expensive to repair.

However, for flashing to be successful, you must seal it properly.

Read our guide to learn how to seal corner flashing and why it’s essential for a roof.

What is Corner Flashing, and Why is it Important?

Corner flashing are moulded pieces of metal that installers form around the roof’s corners when they install it. They also cover the joints of the roof, not just the corners.

They are vital for roofs because they are a frontline barrier against elemental damage like rainwater leaks. While other roofing materials can also provide this role, the corners and joints are some of the most vulnerable parts, so protecting them is critical.

First, corner flashing completely seals off the corners and joints so water cannot get in. Additionally, it helps to stop water from melting ice dams from entering the corners. It also helps to prevent water from affecting other parts of the roof like a box gutter.

Corner flashing also helps to preserve the structure of the roof and house by preventing water from entering the roof. For example, if the roof corners get wet, they are susceptible to mould, which can grow and compromise the roof’s structure. Corner flashing helps to avoid this by keeping the corners dry.

What Problems Can You Face if You Don’t Seal Colorbond Corner Flashing?

Although corner flashing is incredibly helpful, it can be useless if you don’t seal it properly using a high-quality sealant like Colorbond angle trim.

To prove why sealing your corner flashing is vital, we will detail some problems you may face if you don’t.

Here’s what can happen when you don’t seal the corner flashing:

  • Water can infiltrate the roof through the edges of the corner flash. This can cause rot and structural damage, which is expensive and time-consuming to repair.
  • If water gets through and causes mould and rot, it can disrupt the air condition in the house. This can cause multiple problems, including lung infections. These infections are especially common in children, so sealing the corner flashing can save lives if you have a family.
  • If water gets through the corner flashing, it can compromise the insulation in your attic. If this happens, it can cause the cost of your energy bills to increase significantly.
  • As well as damaging the structure, rot caused by water leaks can damage the house’s foundation, making it dangerous to live there.
  • Water leaks can affect the aesthetics of your home's interior. For example, they can cause peeling paint, stains, and discoloured walls.

How Do You Seal Corner Flashing Like Colorbond Flashing?

Now that you understand the consequences of incorrectly sealing your corner flashing, we can detail the sealing process.

Here is every step you must take to seal your corner flashing.

Pick the Right Sealant Product for Your Roof

Before sealing the corner flashing, you need to choose a sealant. Sealant isn’t a one-size-fits-all product; there are multiple different options. 

Research a wide range of sealant types and find one that fits your needs and budget. If necessary, consult with local experts to get their opinion.

You also need to assess if the material will be compatible with the roof materials it will touch. You can find this out from the manufacturer or on the product page. 

Ideally, find a sealant to perform in strong weather like high winds and heavy rain. A weak sealant will degrade in intense weather over time and be ineffective at keeping water out.

Prepare for the Sealing Job By Gathering Materials

Before beginning the sealing job, you must gather all the necessary materials.

Here is a checklist of everything you need before sealing corner flashing:

  • The sealant itself; ensure that it is compatible with the weather in your local area and will work with your building materials.
  • A caulking gun that’s in good condition so you can apply the sealant accurately.
  • Tools to clean the roof surface before sealing. Some of this includes a putty knife for scraping debris and cleaning cloths.
  • Safety gear like a hard hat, safety goggles and gloves.
  • A roof ladder and roof ladder hooks if you have a high roof.

Inspect the Roof and Existing Flashing

The first step to sealing the corner flashing is inspecting it.

You must check the flashing thoroughly and look for any damage or corrosion.

If you find any damage on the flashing, replace it before applying sealant. If you miss this step, water can penetrate the roof through the cracks in the flashing.

Prepare the Roof and Flashing By Removing Debris

You want a work surface that is as clean as possible, so you need to fully prepare the roof corners before sealing the flashing.

First, you must remove all debris from the area near the corners. Debris mainly includes tree branches and leaves.

Also, a cleaner surface around the flashing allows for the best chance for adhesion, so clean the flashing and the gaps around it with a cleaning solution. Also, let the surfaces completely dry before applying the sealant. Doing this increases the chance of the sealant being a strong adhesive.

Apply the Sealant Thoroughly

After completing all the preliminary steps of the sealing process, apply the sealant to the corner flashing by following these steps:

  • Load the caulking gun with the sealant.
  • Apply the sealant consistently along the entire corner of the flashing.
  • Use your putty knife to smooth over the sealant until it completely covers all the gaps.

Final Tips and Tricks for Sealing Corner Flashing

Here are our last tips and tricks to know to seal your corner flashing properly:

  • Ideally, do it when the weather conditions are optimal.
  • Although you must fully seal the flashing, avoid excess because it can create a messy finish.
  • After you apply and smooth the sealant, perform one final check to see if you missed any gaps.

What Benefits Can You Experience When You Properly Seal Corner Flashing?

If you follow all the above steps correctly, you will have completely sealed corner flashing, which will reap numerous benefits, including:

  • An enhanced structure for your roof.
  • Improved indoor energy efficiency because of the insulation protection.
  • Protecting the insulation also allows you to save more on your energy bills.
  • It extends the life of your entire roof.

Final Thoughts on the Importance of Sealing Corner Flashing

In summary, ensuring that your corner flashing has no gaps around the edges is crucial and offers multiple benefits. Most importantly, it can significantly help prevent water from infiltrating the roof. It can also maintain good air quality in the home, support the house’s structure, and reduce energy bills.

In addition to the sealant, you must purchase a high-quality flashing product to extend the roof’s life and defend it from water leaks. Combining this with an excellent sealant is the best way to protect your roof corners.

We have multiple high-quality flashing products on Roofstuff for you to consider on your roof. We can also answer many of your roof protection questions in our Roofstuff blog.

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