Free Delivery


Free shipping on orders over £125 Net.

*(excludes Scottish Highlands, Northern Ireland, Eire, and Uk Islands)



All Our Products Are Competitively Priced
Without the Compromise On Quality.

Safe & Secure


Sagepay & Paypal is a safer, faster, more secure way to pay online.

Chimney Liner

Flexible Flue Chimney Liner

Here is what`s trending on national chimney supplies right now


There are many types of flue liners on the market for wood burners and it's often difficult to know what to choose.

Chimney liners for wood burners and stoves should be durable and capable of standing up to the force of being pulled through the chimney stack. The liner should also be able to withstand the high temperatures generated when the wood burner is in use and during damp conditions that often occur inside chimneys. 

At National chimney supplies we only sell superior solid fuel flexible liners that are manufactured from the best grade of stainless steel. This will ensure that the liner you choose will last for many years and we offer a lifetime warranty on our flue liners*. Also make sure that the liner you buy is the right size for your Installation. We offer our liners in diameters from 4" - 8".

Introducing Ultraflex chimney liner

Made with “triple lock” construction and complete with a  lifetime guarantee, in a choice of 316/316 and 904/904 stainless steel grades, these flexible chimney liners are perfect for ensuring proper draft and preventing the dangerous accumulation of smoke byproducts like tar and creosote. Suitable for chimney repairs or new wood-burning stove installations alike and compliant with UK building regulations, Ultraflex liners are HETAS approved for use with DEFRA approved stoves, fireplaces, and appliances.

Do I need a chimney liner?

In most situations you will need to line the chimney flue when installing a wood burning or multi-fuel stove appliance or fitting an open fireplace. The main reasons are:

Protecting the chimney structure

The liner acts as a barrier between the combustion byproducts and the chimney's masonry or metal structure, preventing damage to the chimney walls from heat, corrosive gases, and acidic condensation, and thus prolonging the life of the chimney.

Improved draft

A properly sized chimney liner ensures an optimal draft, essential for the efficient function of the system and ensuring proper ventilation.

Enhances safety

By containing high temperatures and preventing heat from coming into direct contact with combustible materials, liners reduce the risk of fire and structural damage as well as preventing harmful gases, like carbon monoxide, from leaking into the living spaces of the home.

Increased heating efficiency

A well-insulated chimney liner minimizes heat loss through the chimney walls, ensuring that more heat is retained within the home and improving the overall energy efficiency.

Easier maintenance and cleaning

 A smooth, continuous liner makes it easier to clean and maintain the chimney, preventing the buildup of creosote and other combustible  products that can lead to chimney fires or obstruct the flow of gases. To improve the lifespan of liners, we recommend occasional chimney inspections, cleaning &maintenance ( a chimney sweep can do this for you).

What is the difference between 316 and 904 flue liner?

The main difference between 316 and 904 flue liners lies in the grade of stainless steel used in it’s manufacture. These grades refer to the specific alloy composition and properties of the stainless steel. Here's a comparison between the two:


316/316 chimney liner

904/904  chimney liner

Material composition

316 grade stainless steel inner & outer layer, containing 16-18% chromium, 10-14% nickel, and 2-3% molybdenum.

904 grade stainless steel inner and outer layer, containing a higher percentage of nickel (23-28%) and chromium (19-23%), and 4-5% molybdenum.

Corrosion resistance

Good corrosion resistance and are suitable for most residential applications, such as wood-burning stoves, gas fireplaces, or oil furnaces.

Higher corrosion resistance, making them more suitable for more demanding environments, such as coal and peat fires, or in situations where higher temperatures and more corrosive byproducts are expected. Also ideal where increased durability and longevity are required.

Durability and lifespan

Durable and can last for many years in typical residential applications. Lifespan might be shorter in more demanding environments or with more corrosive fuels.

Longer lifespan due to their enhanced corrosion resistance and improved durability, making them a better choice for heavy-duty applications or when a longer-lasting liner is desired.

Suitable for

Dry seasoned wood, gas, oil and low sulphur coal.

Dry seasoned wood, gas,oil, low sulphur coal, coke, peat and smokeless fuels.


Cheaper than 904/904

More expensive than 316/316

How long does the chimney liner last?

The Ultraflex brand of chimney liners, in both 316/316 and 904/904  both come with a lifetime guarantee, applicable for as long as you own the property.

Buy Your Chimney Liner Online From National Chimney Supplies 

How to order

Simply find the items you need on this website and checkout securely, or call our sales team on 01143 583399 for assistance.

Fast Uk delivery

Delivery to the UK Mainland is 2 -3 days, with Scottish Highlands, Islands, Channel Islands etc up to 5 days. Please see our delivery information page.

Order with confidence with our returns guarantee

We will happily receive returned goods that have been over-ordered or ordered by mistake, please note we will pass any return courier costs onto the customer for this. Please contact us if this is required and we will inform you of the costs.

Should you wish to cancel an order placed with us please let us know ASAP by telephone (you will find the number on the Contact us page) Cancelling orders normally incurs no cost unless products have been specially produced for you order. We will advise you of this on cancellation.

Please note that replacement items can only be sent FOC if the delivery has been signed for as damaged. Other than this any replacements and delivery cost will need to be met by the customer.

Vat no. 173389871- Company No. 08618240 - Registered Name: Chimney Supplies Ltd t/a NCS - Copyright © 2023-present National Chimney Supplies