The chimney flue, also known as the chimney liner, serves several important functions, all of which influence the safety and overall performance of your chimney. Damage of any kind–cracks in particular–can present an urgent safety hazard, and you will need to repair it before you can use it again.

Before you call upon the certified experts at Brick + Ember Outfitters Indy to inspect, repair, or even replace your flue, make sure you understand the causes and risk factors associated with chimney damage.

What Does a Chimney Flue Do?

The chimney flue is a pipe-like liner that helps any chimney operate safely. While a chimney without any lining is technically still a chimney, the flue is considered an essential part of the structure.

Operating a chimney without a liner is extremely dangerous; however, a chimney with a cracked or otherwise damaged flue presents its own unique risks. Below we explain what a properly functioning flue does and how even minor cracks can spell trouble.

Flues allow your chimney to heat your home more efficiently

Chimney liners should be built to perfectly fit the size of your chimney. A proper fit from your flue prevents the products of your fireplace or stove from getting lost to inefficiency. Additionally, cracks in the flue can lead to drafts. Your chimney may also be more susceptible to buildup of highly flammable compounds in wood-burning appliances and carbon monoxide in gas-fueled ones.

A chimney flue prevents the rest of your house from coming into contact with combustible materials

It has repeatedly been found that chimneys that have no liners increase the risk of fires, especially when they have been built in close proximity to wood or other flammable materials. 

Without a properly fitted and functioning flue to control the movement of combustible materials, heat and gases move so quickly that they can ignite a flame when they make contact with building materials like wood or insulation.

A crack or other malfunction in your chimney flue can cause some of the same issues you would encounter if your chimney had no flue at all.

Liners protect the structure of your home from the harmful byproducts of combustion

Over time, the continual presence of smoke, ash, and other byproducts of burning can do harm to your chimney and the surrounding architecture. Stone work is particularly vulnerable to long-term damage because the gases inside a chimney are acidic and can corrode even the finest masonry work.

These gases can penetrate the bricks of your chimney, which gives them the potential to leak into your home. Carbon monoxide is especially dangerous.

This is why it is so important to inspect your chimney flue regularly for cracks, so that you can address the problem before it becomes more hazardous and costly to repair.

What Types of Chimney Flues/Liners Can I Use?

Now that you understand the dangers of a cracked chimney flue, it’s time to know what to look for when you need to repair or replace your liner. There are three main materials commonly used to line chimneys. Let’s see which one might be right for you:


Most chimney liners are made from clay tiles. Clay is a popular choice because it’s inexpensive and easy to find. Going this route does come with limitations, though.

Clay tiles cannot distribute heat evenly in the event of a chimney fire. As a result, they might struggle to contain all the liquid byproduct that results from combustion.


Metal chimney flues are often used when a chimney’s original lining requires an upgrade. Commonly made from stainless steel, metal liners are chosen for their superior durability and dependability. 


Cast-in-place liners are constructed from lightweight yet durable cement, which allows gases and toxins to escape the chimney freely. Cast-in-place flues come with a couple of key advantages: they accommodate all types of fuel and provide much-needed structural reinforcement to older chimneys. 

We Can Help!

Whether you use a stove or a fireplace, chimney safety has to stay at the front of your mind. Regular inspections can detect and prevent cracks in your chimney flue that can lead to fires or structural damage. Whenever you’ve decided your chimney is due for some care, trust the experts at Brick + Ember Outfitters Indy to get it done the right way!