Commercial, Mixed-Use and Strata Roof Maintenance in Vancouver, B.C.

5 Causes Of Roof Leaks Around The Chimney And It’s Best Solutions

5 Causes Of Roof Leaks Around The Chimney And It’s Best Solutions

The warmth of a blazing fire on a chilly winter evening is a blessing for every homeowner having a chimney. Chimneys have been an integral part of the roofing system for ages. However, as the seasons pass and the chimneys get older, some problems pop up.

One of the most common issues is leaks, caused for several reasons. Such as uncovered chimneys, worn-out materials, faulty flashing, damaged chimney crowns, chase flashing, condensation, and a few more.

In this article, we will be understanding the structure of a chimney. Plus, discussing all these reasons of roof leaks around the chimney. Along with what could be done to prevent this situation.

Understanding the Chimney.

A chimney houses fire and smoke. Two elements that could completely destroy your home and health, if not managed efficiently. That’s why learning about the basic structure of a chimney is important.

Moreover, chimneys are probably the highest point of any structure. Hence, they are hit by the elements constantly. Knowing the chimney well will help you identify any issue prematurely. And address it before it escalates.

Chimneys generally consist of a basic structure made up of the following parts.

Bricks And Mortar.

The structural integrity of your chimney depends upon the bricks and mortar used in its construction. These are the basic components used to build a chimney. Good quality construction material will result in a long-lasting chimney.


The flue of a chimney is the vertical shoot that lest the smoke and combustion material exit you’re home.


Liners contain the fire within the fireplace. In many countries, it’s mandatory to line the flue with a chimney liner. These liners are often made up of clay tiles, due to their durability and relatively cheap cost.

If you spot a crack in these liners it’s necessary to replace them, before using the chimney again.


The topmost part of the chimney is the chimney cap. It’s often made up of metal, to avoid unnecessary debris and animals from entering the chimney.

Chase Covers.

Chase covers are commonly spotted on prefabricated, factory-built chimneys. These covers cover the opening of the chimney. They are made up of a variety of metals including, copper, Aluminum, and Stainless steel.

Chimney Flashing.

Flashing is placed on the exact location where your chimney intersects with your roof. It’s made up of vinyl and various metals.

Chimney Crown.

A slab of cement that covers the mouth of the chimney, except the flue, is called the crown. It’s also referred to as the wash of the chimney. It performs the same functions as the cap of the chimney.

Fireplace Damper Or Throat Damper.

Fireplace dampers are located at the throat of the chimney above the firebox, hence the name. Its primary job is to prevent heat from escaping the house, once the chimney is put out. When it’s re-lit the dampers are open to let smoke pass.

Smoke Chamber.

It’s situated right between the throat damper and the flue. A smoke chamber assists in compressing the combustion byproduct, for it to exit via the flue. And not return to the firebox below.

Things That Make A Chimney Leak. (Roof Leaks Around The Chimney)

As professional roofers, we tackle roof leaks almost every day. And in many cases, the culprit is the chimney. When one or multiple parts of the chimney are damaged it may lead up to roof leaks.

Let’s see some common causes of chimney leaks. (Roof leaks around the chimney)

Uncovered Chimney.

An uncovered chimney invites, rain, animals, and other debris into it. When water enters the chimney, it causes certain parts to rust. Also, when animals, animal excreta, and other dirt accumulates in it, it blocks smoke from getting out. Furthermore, if this dirt decomposes within your chimney, it may cause CO poisoning. Which have harmful effects on health.

A chimney could be missing a chimney crown or the flue could be without a cap. Either way, this could be the primary reason for a leaking or malfunctioning chimney.

Wear and Tear.

Just like the house itself, chimneys deteriorate with passing time. Although the masonry may be designed to last for decades, it does not sustain against the weather without proper maintenance.

Chimneys are made of bricks and mortar, which are ultimately made up of earth and water. As the chimney becomes older, the mortar chips and falls, leaving gaps between the bricks. When water seeps through these gaps it is absorbed by the old bricks.

As the temperature fluctuates, the water freezes and expands causing the bricks to crack. Eventually, these cracks will expand, weakening the core structure of the chimney. This results in more water seepage and the cycle go on, causing leaks and other evident damage.

Missing or Improperly Installed Flashing.

One of the most vulnerable spots on the roof is where the chimney intersects with the roof. This area is much more prone to leaks than the rest of the chimney.  Simply, because the roof and the chimney are two different structures connected to one another.

Sometimes there are gaps around this area, which create an easy gateway for water. These gaps could be sealed with sealants as exterior caulks. However, to make sure no water seeps in, metal flashings are used.

Flashings are an important part of the roofing system. They create a tight waterproof seal around the edges and joints. If these flashings are damaged, faulty, improperly installed, or missing altogether. Leaks are inevitable.


In 1900 when wood fueled the chimneys, chimney liners were hardly needed. As the soot and smoke were completely dry.

A few decades later, where gas is burnt in chimneys instead of wood. Its residual fumes contain moisture due to decreased temperature. This causes condensation inside the chimney. Which manifests itself in the form of leaks.

If your chimney is old or had been converted to gas at some point in time. Then make sure you have suitable liners lining the inner walls of the chimney.

What to keep in mind to prevent roof leaks around the chimney:

Chimney leaks can be easily avoided by practicing a few precautions.

Regular maintenance.

Regular roof inspection and follow-up roof maintenance should not be skipped. Even if your chimney looks fine, it may be internal damage.

Roof maintenance handles small roof issues and notifies you of the possibility of any future major roofing problems.

This service is an investment towards your roof and not an expense. It helps you get the most out of every roofing part including the chimney and roof leaks around the chimney.

Periodic Cleaning.

A regularly used chimney may have the remains of the burnt fuel. A chimney brush can be used to get rid of this dirt blocking your chimney and sticking to its walls.

This will considerably reduce the chances of condensation and leaks.

Chimney Caps.

Install a chimney cap. This acts as a tarp or an umbrella and prevents rainwater from directly entering the chimney. Eliminating the possibility of leaks due to the downpour of rainwater.

This is a small solution to a big problem.

Prevent Pooling Around The Chimney. (Roof leaks around the chimney)

Water pooling may be a common phenomenon occurring on flat roofs. However, it’s observed that water pools behind the chimney on a sloped and low-sloped roof too.

The wall of the chimney act as a dam collecting rainwater. This could be countered by installing flashing and using silicone exterior caulks. Moreover, there needs to be a peel-and-stick membrane detail under the flashings. As metal flashings will encourage condensation which then encourages the plywood to rot by the effect of moisture

Also, chimney back pans must have a slope. In not the accumulated water will rust the metal back pan. This will allow the rainwater to flow off the roof into the gutters. Causing no leaks in the process.


I hope this article offers you a good insight into chimney leaks, roof leaks around the chimney. And the tips above help you to enjoy your chimney. If you have any further questions let us know in the comment section. We would love to answer them.

Moreover, if you are looking for a reliable roofing service to deal with your chimney or roof in general get in touch with us TODAY!

Leak-Stop is a one-stop destination to meet your roofing-related requirements. We offer roof repair, replacement, maintenance, and inspection services all over GVRD (Greater Vancouver Regional District).

We offer a free inspection to first-time clients. Connect with us TODAY at 1 866 777 0084 for immediate assistance!

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