You don’t need a chimney liner in an old chimney unless they have become unreliable due to damage, a blockage, or if they are leaking- if you are unsure, or suspect that things aren’t quite right up there, get it checked out. If you have a wood-burning stove, then you usually need a chimney liner if the old chimney is leaking for some reason.Leaking chimney

If you have an open fireplace, you only need a liner if your chimney is leaking.

Is a liner for open fires a legal requirement?

If you have an open fireplace, you may be wondering where you stand on this, with regard to the law.
The age of your property is the only factor that affects your answer.

When you use an open fireplace in a newer home, a liner is not essential if you have a new chimney. This requirement is outlined in Document J of the Building Regulations. This is a government document that lays out rules for the safe installation and use of heating appliances, stoves, etc.

It's different if you live in an older house. If you plan to renovate an old open fireplace, Document J states ‘Where it is proposed to bring a flue in an existing chimney back into use or to re-use a flue with a different type or rating of the appliance, the flue, and the chimney should be checked and, if necessary, altered to ensure that they satisfy the requirements for the proposed use’.

As long as an open fireplace can still vent smoke and combustibles away from a fire, it can be reused without a chimney liner.
In order to do this, a chimney professional should carry out a CCTV inspection of your chimney as part of a level 2 chimney inspection.

Smoke leakage test, full pressure test, and exterior and interior CCTV inspections are all part of a level 2 chimney inspection and sweep.

A chimney sweep who performs a level 2 inspection can provide you with a report and video footage of the chimney's interior. You can use this as evidence if a local building inspector objects to your open fireplace. So, it's definitely worth getting your chimney inspected.

Line your chimney with a stainless steel linerChimney fire

Even if you aren't legally obligated to use one, we strongly recommend you use a chimney liner with an open fireplace.
Why? There are a host of benefits to doing this.


The safety of your chimney is significantly improved by using a good chimney liner.
With an open fireplace, your chimney accumulates soot and creosote, which is combustible.
Creosote buildup in your chimney can cause blockages, which can sometimes lead to chimney fires if allowed to build up.
By funneling combustible materials up and out of existing chimneys, liners reduce the chances of this from happening.


Furthermore, a quality chimney liner protects your chimney in the same way.
A class 1 chimney that's unlined (i.e. bricks and mortar), or an older clay masonry chimney, needs this attention. Clay tiles just don't do the job as well.
As combustion by-products, such as creosote, are caustic, they can corrode bricks and mortar, and cause chimney leaks over time.
Smoke can leak into your living space from chimney leaks, not to mention into your neighbour's as well!
It extends the life of your chimney by preventing flue gases and caustic combustible by-products from coming into contact with it. Avoid the need to repair existing chimneys by establishing the proper lining systems.


Using flexible metal liners can prevent chimney problems through installation, such as combustible materials and condensation.
Using metal flue liners can reduce the build-up of condensation since it keeps the flue gas warm as it travels up and out. It also expands and contracts as it warms up and cools down, which prevents creosote formation. This doesn’t eliminate all the potential problems forever, but it certainly improves things significantly.


If you want an efficient fireplace, you really do need a chimney liner.

Having sufficient ‘draw’ through the fireplace and up the chimney is the key to creating a well-functioning fireplace in your home. During combustion, your open fireplace should naturally draw air in from its surrounding room.

It is vital, however, that your room is sufficiently ventilated in order to ensure a good draw.

There are a lot of older chimneys that are too big in diameter for the fireplace and the wood burner or stove. The smoke from one of these chimneys rises too slowly and leaves condensation on the way up. Eventually, this leads to creosote deposits, condensed water, and dampness inside the chimney.

Besides leading to a poorly burning fire, this can result in smoke and combustibles drifting back down the chimney walls, and into your living room in the worst cases.

Not ideal!

With high-quality chimney liners, smoke and combustibles can travel up your chimney well-ventilated.
This will result in a better draw for your fire.

You will also experience less smoke and guttering, less chimney downdraft, and they will burn better and burn more fuel efficiently.

Registerplate for flue for an open fire place

How should I line my open fireplace chimney?

You may now be wondering what type of is best for your open fireplace. 
Consider these factors when choosing:

  • Liner material.
  • Liner diameter.
  • Liner length.

What material or grade flue liner should I use for chimney liners?

A functional chimney liner should be made of the correct material first and foremost.

904-grade stainless steel liner and burning coal:

Open fireplaces that burn coal require steel liners made from 904 grade. Please note that traditional coal is now banned in the UK, and came into effect in May 2023. If you have been burning coal, you can buy alternative fuels from your coal supplier instead.

The molybdenum content of 904-grade stainless steel makes it highly corrosion-resistant. The high alloying content also prevents stress corrosion cracking.

Consequently, chimney liners made of 904-grade steel will provide a long service life and will be able to handle coal fire byproducts that are caustic and combustible.

Here at Flue Pipes, we sell 904 grade stainless steel liners that are manufactured with two treated skins, making them highly and extremely durable, and ideal for long-term use. Trust us for choosing the perfect stainless liner!

316-grade stainless steel liners

An open fireplace that burns seasoned wood should only use stainless steel 316 grade.
The molybdenum in 316-grade steel makes it corrosion-resistant and long-lasting. Check out our stainless steel liner range here.
We recommend buying a 904-grade flue liner if you plan to burn both seasoned firewood and coal in your open fireplace.

How thick is a fireplace chimney liner?

The thickness of the liner itself is 1mm. You can get accessories such as a pot hanger and even a bird guard, like the ones below, for your chimney. Check out all these products in our Flue Liners.

How long is an open fireplace flue liner?

It is essential to consider your chimney height when choosing the correct length flue liner.
It is common to draw a flexible flue liner down the chimney by rope from the top and then affix the top of the chimney liner to the chimney by standing on the roof. A pot hanger is typically used to secure the liner to the chimney.

The installation process requires a long flue liner, so we recommend that you buy one that's longer than you need.
Building Regulations prohibit sticking together two separate liners. Flue liners can be cut down to size.
Flue liners are ideal for open fireplaces if you pay attention to their diameter, length, and material/grade.
Please contact our friendly expert team if you are unsure which flue liner is best for your individual circumstances. 

What material or grade liner do I need?

It's important to choose the correct, effective flue liner. The type of flue liner you need will depend on the type of fuel you burn. It is important that you consult the manufacturer’s instructions to make sure the chimney liner is properly installed. The liner should also be inspected regularly to ensure that its material is in good condition. 


Open fireplace: how to care for these liners

Your flue liner should be swept regularly to prolong its life. It's recommended that you have your flue liner inspected and swept quarterly (e.g. four times a year) if you burn wood or coal in your fireplace regularly.

Sweeping a metal flue liner requires the right tools. Ball-topped polypropylene brushes of the right diameter must be used. Any damage to the chimney liner can be avoided by using these kinds of brushes.

A qualified chimney sweep is always recommended to get your chimney cleaned.


How to choose a liner for open fire

Find chimney liners and flue liner kits that are suitable for burning seasoned wood or coal in an open fireplace.

Accessories for your liner

Whenever you install a new liner, make sure you have the other necessary parts that you need to complete your project. This can include a rain cap or a CO2 detector.

Carbon monoxide detectors are an absolutely essential fireplace accessory. In fact, under proposed new regulations, a carbon monoxide alarm will be mandatory whenever a new fireplace is installed.
We strongly recommend getting ahead of these changes now by buying a CO2 alarm.

Designed for homes of all types, our Carbon Monoxide Detector has a sealed lithium battery that will last at least seven years, plus a 15-to-30-year guarantee!

Did We Miss Anything? 


Hopefully, you just got all the answers you need, but maybe you still have a question. If you want to know about this or any other topic relating to domestic burners and flue pipes, then please check out our FAQ page.

Here is our guide to UK regulations or our installation guide.

If you have a more specific problem, or you need your purchase sorted out quickly, then take advantage of our years of experience and head to head to our contact page.