Is your chimney liner still doing its job? If you’re not sure, it might be time to take a closer look. A damaged or worn-out chimney liner can lead to serious safety risks, including chimney fires and carbon monoxide leaks. In this guide, we’ll cover the top signs your chimney liner needs replacing - and what can happen if you don’t.

Key Signs You Need a New Chimney Liner

1. Visible Cracks or Deterioration

Look for cracks, holes, or missing sections inside the flue. Damaged liners allow heat and toxic gases to escape into your home’s structure.

2. Rust or Damp Patches Around the Chimney

Moisture issues often signal liner problems. Rust on your stove or fireplace components is another tell-tale sign.

3. Debris or Tile Fragments in the Fireplace

Finding bits of clay tile, soot, or liner material in your fireplace? Your chimney liner could be crumbling.

4. Poor Draught and Smoke Blowback

If your stove or fire is difficult to light, or smoke isn’t drawing up the flue properly, a damaged liner could be restricting airflow.

5. Persistent Chimney Odours

Strong smoky or chemical smells - especially when your appliance isn’t in use - usually point to creosote build-up or a failing liner.

What Happens If You Don’t Replace a Damaged Chimney Liner?

Putting off a chimney liner replacement can lead to:

Increased risk of chimney fires
Carbon monoxide leaks into your home
Structural damage to your chimney and property
Expensive long-term repair bills

Keeping your liner in good condition is essential for safe, efficient heating and protecting your home.

How Long Does a Chimney Liner Last?

Stainless steel chimney liners: 15–20 years (or longer with good maintenance), this depends on the quality of the liner that has been installed and also that the correct fuel type has been used for the type of liner you have. For example 316 stainless steel is only suitable for burning wood, whereas 904 grade stainless steel is suitable for multifuel, so if you burned multifuel on a 316 grade liner it will deteriorate much more quickly. Our Ultraflex flexible flue liners come with a lifetime warranty and are available in both 316 and 904 stainless steel.

Clay tile liners: Can deteriorate much faster, particularly in older chimneys or with frequent use

Twin Wall Flue Systems: Our Twin Wall Flue Systems come with a 25 year warranty and are suitable for use with solid fuel and gas/oil appliances where no existing chimney stack is available.

Book a Chimney Inspection & Shop Replacement Liners

If you’ve noticed any of these warning signs, arrange a professional chimney inspection without delay. At National Chimney Supplies, we offer a full range of high-quality chimney liners for wood burners, open fires, and gas appliances - plus expert advice to help you choose the right product.

Browse our range of chimney liners here or get in touch for a free consultation today.