Chimney Flashing Leaking? What to Do with a Leaky Chimney

close up of chimney with chimney flashing around it on roof
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close up of chimney with chimney flashing around it on roof

If your home has a chimney built into it, you probably consider yourself lucky. After all, not all homeowners get to cozy up to a fireplace during the long winter months.

However, chimneys do require a certain amount of maintenance. Specifically, one of the issues you may come across is a leaking chimney flashing.

There are many things that can cause your chimney flashing to leak; likewise, there are many ways that you can fix this problem. Our informational guide will direct you to the best information, along with the best solutions.

What is Chimney Flashing?

Chimney flashing is essentially a seal that covers the surrounding area of your chimney where it meets your roof. Typically made from a sheet of metal, the flashing forms a waterproof connection that keeps rain, snow, and other elements and debris from washing up and accumulating against the chimney. It instead helps direct water down and away from the structure.

More than anything else, your chimney flashing serves as weather stripping. It’s a critical component to ensuring your chimney is protected from water damage and stays structurally sound.

Your chimney flashing has two significant parts: the step flashing and counter flashing.

These two L-shaped chunks of metal work together to form an impenetrable seal around where your chimney meets the roof. The step flashing sits under the roof shingles along the brick part of the chimney, while the counter flashing covers the step flashing and is embedded into the brick. Both of these pieces are sealed together with caulk.

How to Know Your Chimney Flashing is Leaking

Chimney flashing leaks don’t have to be difficult to repair, but leaving them untouched for too long can lead to significant and dangerous structural damage to your chimney. A leak can allow water to seep into not only your chimney and fireplace but also your attic and ceiling. These leaks can also cause roof and drywall damage through wood rot.

If you were unaware of a flashing leak and start to see signs of water damage in your ceiling or attic, it might be time to have an inspection on your chimney, as it may be the cause. Otherwise, there are alternative ways that you can regularly check for leaks.

One sure-fire method is to run a hose around the area where your chimney and roof meet. After running the water for a few minutes, check the inside of the chimney for signs of water or moisture.

Scheduling annual inspections can also help you identify any chimney flashing leaks. This is the preferred method, as you should have your chimney inspected annually anyway to locate or prevent additional problems.

Causes of Chimney Flashing Leaks

Like other areas of your home, your chimney is bound to take on typical wear and tear just from everyday use and time. Additionally, since your flashing is located outside, it also is constantly exposed to the elements and severe weather, speeding up everyday damage.

Between rain, snow, ice, and other objects that can bump and hit your flashing, you may find cracks and crevices starting to form. You might also see a gap along the caulk used to seal the seam between the flashing and chimney, resulting in the seal separating from one or both surfaces.

Cracks in your chimney crown, the effects of weather, wear and condensation on the metal flashing, and leaking bricks can all cause leaky flashing.

In a lot of cases, you can actually repair the flashing rather than replace it altogether. However, significant damage could require a complete replacement.

When to Replace Your Chimney Flashing

Of course, as soon as you notice a leak or signs of water damage, you should contact a professional about having your chimney flashing inspected and replaced.

If you haven’t noticed any signs of a leak, you may still consider replacing your chimney flashing during convenient times. You flashing comes into direct contact with water frequently since it’s exposed outdoors, so it’s bound to take on typical rust and corrosion.

For that reason, if you’re having other forms of work done on your roof, you might consider replacing your flashing while you’re at it. For example, if you are having shingles replaced or repaired, that would be an ideal time to check the flashing and possibly replace it.

You should have your flashing inspected annually to detect any problems as soon as possible. An inspector may recommend you replace the flashing if they find any of the following:

  • Flashing is missing
  • Flashing is rusted through
  • It is falling out
  • Flashing is covered with roofing tar
  • The Flashing has visibly separated from the chimney

In the above cases, it’s likely that you will have to do a full replacement.

How to Replace Chimney Flashing

Replacing or repairing your chimney flashing is best done by a professional. Doing so on your own can be extremely dangerous and can lead to a greater chance of user error.

The first step to replacing your chimney flashing is to make sure you have a safe and secure attachment to your roof. This is critical, as a fall could lead to serious injury.

After you are secured on the roof, remove the shingles surrounding the chimney flashing. At this point, you’ll be replacing the step flashing and following up with weaving the singles and flashing back in.

Finally, you will install the counter flashing, sealing everything off with caulk to ensure there are no cracks and crevices for leaks.

Installing a Chimney Cricket

Many roofs implement the use of a chimney cricket to help with water flow. This additional structure is a special kind of flashing that diverts water to prevent it from pooling on your roof. It sits at the back of your chimney, forming a pointed ridge for water to slide down.

You can have a chimney cricket installed using either wooden pieces or metal. This process will also involve using caulk and sealants to ensure water doesn’t get trapped underneath.

Can You Use Sealant on a Leaking Chimney Flashing?

For small cracks and leaks, you can use various sealants as a temporary fix for your leaking chimney flashing. However, it’s important to note the emphasis on the word “temporary.”

Cracks and leaks can quickly grow, and a sealant can only last so long.

In the case of damage to your flashing or leaks, you should always contact a professional for repair, replacements, or advice.

Get Professional Help Today

Above all else, it’s critical to get professional help when something goes awry with your chimney in any way, shape, or form.

Priddy Chimney Sweeps has been in serving customers since 1982 and possesses the experience, expertise, and services necessary to keep your chimney up and running.

Most people call a chimney sweep at the first sign of trouble, but it’s important to know that you should also call for regular inspections and routine maintenance. Book an appointment online today or call us with any questions or concerns you might have.