A chimney flashing is an area that connects your chimney to your roof, creating a waterproofing seal that protects both structures from moisture that could lead to related damages.

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In this article, you will understand more about vertical chimney flashings, their importance, some common types, installation, and other tips concerning them.

The Importance Of Vertical Chimney Flashing

There are various aspects of a chimney, and all of them have critical roles. If a part of your chimney is cracked, completely damaged, or missing from its place, the safety of your home is at risk, and there’s no exception in regards to chimney flashing.

People often talk about mortar tuckpointing, chimney liners, and other chimney services, but flashing is usually taken for granted if not disregarded completely. However, chimney flashing is especially important for the functionality of your chimney.

Common Types Of Chimney Flashing

Now that you have a general perception of chimney flashings, you’re going to want to learn about the various types. When determining which of these sorts to acquire, think about where you live and the weather you’ll be dealing with

You should also consider your roof’s shape, size, and material. Below are the four types of chimney flashing.


Aluminum flashing is one of the most frequent or conventional types of flashing. It is usually less expensive and can be installed on most, if not all, types of roof materials. Although aluminum does not rust, it can corrode.

In addition, it comes in large rolls and can be cut to match any shape, this type of flashing is a popular choice among contractors because it is both cost-effective and versatile.

Vinyl And PVC Flashing

Vinyl flashing is a more lightweight option for a chimney’s construction material, and it’s a favorite choice among contractors. It is more expensive than aluminum. However, it is not the greatest material for chimney construction. 

However, it’s not unheard of in locations where severe weather isn’t a regular occurrence. On the other hand, vinyl can get brittle, leading to cracking and other issues, making it unsuitable for places with a lot of rain or humidity.

In addition to that, vinyl isn’t the most durable material for enduring heat, which is why it’s rarely used in chimney construction.

Steel And Galvanized Steel Flashing

Steel is a heavyweight material frequently used to construct roofs and chimneys. It’s one of the most durable flashing materials, and it doesn’t corrode as easily as other types. 

Most steel flashings are zinc-coated to increase longevity. The zinc treatment on steel flashings will corrode first rather than the steel itself. 

Because of its weight, constructing a steel chimney takes longer, and mounting the chimney takes much longer. Because it is more expensive, it is rarely used for complete roof applications. It is, nevertheless, ideal for chimneys.

Copper Flashing

Copper is the best material on the market for chimney and roof flashing construction. It’s light, doesn’t fracture or shatter easily, and withstand high temperatures and harsh weather. However, it is also one of the most costly of the four possibilities.

However, copper is also difficult to shape, making chimneys with rounded or complex angles hard to construct. To effectively install copper flashing, you’ll need a special sealant. The sealant will add an extra layer of defense against infiltration.

Watch Out For Leaking Flashings

If you have moved into a new home lately or haven’t done any work on your current chimney in a long time, you should keep a lookout for signs of damages and faulty flashing. Chimney flashing is a common contributor to leakages and can cause major concerns if not managed correctly.

Chimney flashing failure could damage your roof and attic. Roof damage is not to be taken lightly, so it is critical to find a roofing company to help you fix any damages you notice at once. Not to mention your actual chimney could sustain heavy damages from poor flashing.

How To Install Vertical Chimney Flashings?

If you notice your ceiling has water stains, take a look at your chimney flashings. You might see that your flashings are damaged or completely rusted.

In this case, you might need to replace your chimney flashing. To help you install vertical chimney flashings, here are the steps you need to follow:

1. The first step is to remove the old flashing. Scrape away old flashing and cement with a hammer and chisel.

2. Next, cut the base of the flashing. If you don’t want to cut the flashing yourself, you can have this done before at a sheet metal store. 

3. After that, use tin snips from the base of the flashing to fit neatly along the front of the chimney. Then bend the flashing on one side around one of the chimney’s edges.

4. Now, you will need to secure the flashing. Place the flashing to fit against the front of the chimney. The roof’s shingles should overlay the part that levels with the roof. The angled edge should fit around one of the chimney’s corners.

5. The next step is to clip the flashing where it meets the chimney and bend it around it with more tin snips. Then hammer in four galvanized nails equally spaced into the flashing part that touches the roof.

6. From here, install the corner and step flashing. Fit a piece of square step flashing measuring eight inches (or 20.3 cm) on the top-front of the chimney’s corner. 

7. Apply a little caulk to the chimney’s corner, where the roof meets the chimney. The step flashing can be placed over the caulk and onto the chimney.

8. Then hammer two roofing nails to join the flashing and the roof. Then, using a hammer and roofing nail to fix a shingle over the corner flashing.

9. Next, place a piece of flashing eight inches (or 20.3 cm) against the chimney. The initial piece of flashing must be slightly overlapped by the shingle covering it.

10. After that, use a nail to secure a shingle over the second piece of flashing. Keep doing this process until you’ve gone all the way around it. And you’re done.

Professionally-Installed Flashings Protect Chimney

Remember that brick and mortar joints will be susceptible to cracks if damages from faulty flashings are not resolved and risk the chimney’s structural solidity. The best option is to get a chimney inspection at least once a year to prevent this situation from happening.

It’s better to be safe than sorry. Repairing any minor flashing damage is better than having to repair your entire roof and chimney because of too much water damage. If you are unsure of what to do when installing chimney flashings, it’s best to consult a professional.

Editorial Contributors
Matt Greenfield

Matt Greenfield

Matt Greenfield is an experienced writer specializing in home improvement topics. He has a passion for educating and empowering homeowners to make informed decisions about their properties. Matt's writing focuses on a range of topics, including windows, flooring, HVAC, and construction materials. With a background in construction and home renovation, Matt is well-versed in the latest trends and techniques in the industry. His articles offer practical advice and expert insights that help readers tackle their home improvement projects with confidence. Whether you're a DIY enthusiast or a seasoned professional, Matt's writing is sure to provide valuable guidance and inspiration.

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