How To Install Roof Vent Flashing: Guide to Waterproof a house

Roof flashing refers to the process of using a durable metal barrier to prevent water from finding its way into your rooftop! Due to the crucial role flashing plays in protecting your roof, the installation of flashing is widely recommended.

If you install a bathroom fan or venting system, you will have to install a venting system through the roof. It is important that the flashing around this vent is properly installed to avoid water leaks.

However, many homeowners are unsure of how flashing is installed. Plumbers often get called out for water leaks that turn out to be the result of poor installation of the roof. Let’s see how we can get it right!


How you install roof flashing depends on the design and layout of your roof. Pre-formed flashing parts can be readily purchased to be easily installed. While it’s possible to take a DIY approach to this installation, this should only be attempted by those with the applicable knowledge and skills.

If you’re looking to install roof flashing, we’re going to break down what you need to know about this process. Firstly, we’ll look at the overall process of installing flashing. Once we’ve done this, we’ll discuss the different types of flashing that can be used to properly protect your roof. 

How Is Roof Flashing Installed for a roof vent? 

Flashing is one of the most crucial components of any homeowner’s rooftop. Essentially, the installation of flashing protects areas of the roof that are prone to developing leaks. Flashing is made from thin metals, such as aluminum, steel, and copper. 

These metal barriers prevent water from leaking into your roof’s underlying system. However, these metal components also direct water away from your rooftop. Flashing can be purchased in various styles, making them easier to install on your roof. 

When it comes down to the installation of roof flashing, there are two main options to consider. By hiring a professional for this project, you can skip this time-consuming process. Professionals are recommended for complex roofs with features like chimneys, skylights, and vents. 

However, if your roof’s layout is more straightforward with few features, it is also possible to install the flashing yourself. To do this, you’ll need to follow the manufacturer’s instructions, which will vary depending on the pre-formed flashing styles you need to use. 

If you decide to attempt this installation by yourself, you’ll need to ensure you’re comfortable working on a rooftop. You’ll need to clear any debris from your roof before installing the flashing. 

If there’s existing flashing on your roof that needs to be replaced, the roofing nails will need to be removed so it can be replaced. 

For those with shingled roofs, the shingles will need to be removed before the flashing can be installed. However, when a new roof is being installed, the flashing can be installed before the shingles. When installing shingles on top of flashing, you need to work from the edge of your roof to the peak. 

To install the flashing itself, you’ll only require the flashing parts, a hammer, and some nails. Of course, the exact installation procedure will depend on the design of your roof and the pre-formed flashing pieces that need to be used. While some types of flashing are easier to install than others, the process generally remains the same. 

Installing Different Types Of Roof Flashing

As we explained above, the process of installing roof flashing generally remains the same for different pre-formed parts. However, in order to install roof flashing, you’ll need to determine which pre-formed styles you require to finish the job and ensure your roof is protected against the elements. 

Continuous Flashing  

Continuous roof flashing is a large piece of metal that is used to carry water to the shingles below. In order to install continuous flashing, the metal will need to be embedded into your roof’s cement and nailed to the appropriate shingles. 

For a more detailed overview of installing continuous flashing – which is also known as apron flashing – you can check out the following YouTube video! 

Step Flashing

Step flashing functions as an alternative to continuous flashing. Instead of using one large piece of flashing, two overlapping parts are used. The use of step flashing can also be used on the corners of your roof as an alternative to drip edge flashing.

You can check out this video if you want a closer look at how step flashing is installed! 

Drip Edges

Drip edge flashing is installed in the corners of your roof. By installing drip edges or step flashing by the corners of your roof, you ensure that rain runs off the roof and does not result in any leaks or damage to your rooftop. While step flashing can be used as an alternative to drip edges, it is also possible to use these types of flashing together. 

To see the processes of installing drip edges, you can check out the following video on YouTube! 

Base Flashing 

When a roof feature like a chimney requires additional pieces of flash, base flashing can be used. By adding base flashing to these features, homeowners can ensure that their flashing is watertight. 

If you want to learn more about installing base flashing on your roof, you can check out the following YouTube video!

Counter Flashing 

Counter flashing is used alongside base flashing. Essentially, counter flashing protects the upper edge of the base flashing. When used together, homeowners can ensure a stronger seal. Of course, this is crucial to protecting your rooftop. 

If you want to find out more about installing counter flashing in conjunction with base flashing, you can check out the following tutorial! 

Valley Flashing 

Where two sloped sections of a rooftop meet, a type of valley forms. To properly direct water from the rooftop, valley flashing should be used in these areas. Valley flashing can even prevent the buildup of dirt and debris on your rooftop. 

If you’d like more insight into installing valley flashing, you can check out this video! 

Vent Flashing 

As the name suggests, vent flashing is used to protect vent pipes. This type of flashing is cylindrical and is fitted around a vent itself. This type of flashing allows water to run around the vent pipe. 

If you want to see how vent (pipe boot) flashing is installed on a roof, you can watch the following video on YouTube. 

Chimney Flashing 

To properly protect your home’s chimney from the elements, chimney flashing should be used on your rooftop. Given that chimneys are prone to developing leaks, chimney flashing is a crucial part of your rooftop flashing. This type of flashing can be used in conjunction with base and counter flashing. 

To see how chimney flashing is installed, you can check out the following video, which visually guides you through the process! 

Skylight Flashing 

While some skylight manufacturers provide flashing for their products, other homeowners will need to install skylight flashing themselves. As the name of this flashing suggests, this type is used to protect skylights from developing leaks. 

To see skylight flashing being installed, you can watch this YouTube video!


The design and layout of your rooftop will determine how you install flashing. You can purchase pre-formed flashing parts for a simple installation. Although it is possible to perform this installation on your own, you should only attempt it if you have the necessary expertise. Alternatively, a professional contractor can be hired to install your roof’s flashing. 

We have discussed roof trusses here.


How to Install Step Flashing and Continuous Flashing along a Chimney or Wall on a Shingle Roof