Chimney Liners Explained
One of the most common questions we are asked by customers wanting to buy a stove is, do I need my chimney lined? In this article, we will try to cover all the important things you need to know about stove flue liners.
Article Breakdown:
- What is a Chimney Flue Liner?
- Which Size Flue Liner Should I Buy?
- The Reasons Why a Chimney Liner is a Good Idea
- Should I Install a Flue Liner with my Log Burner?
- Chimney Sweep; Is it Necessary & Who to Use
What is a Chimney Flue Liner?
Quite a simple answer really... A flue liner, which is often referred to as a chimney liner is a flexible stainless steel tube that hangs from your chimney pot or stack down to the stove pipe that connects to your stove. The flue liner sits on the inside of your chimney and carries the fumes from your log burner or gas stove up your flue liner instead of releasing them into your chimney cavity.
Related Blog: What are the Different Types of Chimneys and Flues?
What are the Different Grades of Flue Liners?
There are two different grades of flue liner available; 316-Grade flue liner and 904-Grade flue liner. We recommend 316-grade chimney liners for stoves that will be used for burning seasoned wood and for occasional use of smokeless coal. We recommend a 904-grade chimney liner for stoves burning a mix of seasoned wood and smokeless coal or smokeless coal on its own.
Both these grades of flue liner should last as long as the stove it is installed with. A good quality flue liner (like the one we supply) can last up to 25 years if maintained correctly and used with the right type of fuel.
What Size Flue Liner Do I Need?
You must always use the recommended flue size for your specific stove or fire and never reduce the diameter of the flue. When buying a log burner or gas stove from our website we provide the diameter of the flue collar within the specifications and this is often a good guide to gauge the correct sized liner required for the stove. The size of the stove collar however does not always correspond to the size of the flue liner you need so ensure you check the manufacturer's instructions before you purchase.
Useful tips:
- You can use a 5” diameter flue liner if you have a DEFRA-approved stove and the manufacturer has confirmed this is compatible (you do not need to increase the flue size).
- If the collar of the stove measures 5” in diameter but you need a 6” flue liner there are adapters available that allow for the increase in diameter.
When measuring the length of your flue liner our main piece of advice is a simple one, you must ensure it is long enough to reach from the top of your chimney to the bottom of the fireplace opening. Connecting two pieces of flue liner together is against regulations; we certainly do not advise this. We would recommend ordering an extra metre or two of flue liner to cater for any bends or offsets within your chimney.
The Reasons Why a Chimney Liner is a Good Idea!
Here we will explain the purpose of a flue liner and why we think it is a no-brainer to fit one with your new stove.
Line Your Chimney for Improved Safety
Older chimneys will often require a flexible flue liner solution as over time they may lose their integrity. Any cracks that form in your chimney that you are unaware of can leak fumes into other parts of the home, a flexible flue should prevent this potential hazard.
This brings us nicely to the cleanliness of your flue/chimney. A wood-burning stove creates smoke which is a product of the combustion, this in turn creates a build-up of soot within the chimney. Excessive amounts of smoke will dirty the inside of your chimney and can form creosote; creosote is incredibly hard to shift and as it builds up within the flue it can create blockages.
A Flue Liner Could Improve the Efficiency of a Stove
An older chimney that does not have a flue liner can be a cold and damp space, it can be difficult for the hot gases to rise and the result is a poor up-draught. Large chimneys measuring over 200mm in diameter may affect the performance of an appliance. Some stove manufacturers specify smaller flues for efficient operation.
Should I Installer a Flue Liner with my Log Burner?
Although it is not a legal requirement to fit a flue liner with a wood burner, most retailers and stove installers recommend that you do. Without a flue liner, it is difficult to determine the quality and performance of the chimney just by looking at it. Issues like poor flue draught, lighting difficulties and shorter burn times are less likely to occur if you opt to fit a flexible liner.
Before installing a wood burner your chimney should be checked by a professional. A newly built chimney may still require a flexible flue liner in order for it to be suitable for a wood-burning stove. For example, if a gas flue liner was originally installed it may not be suitable for a solid-fuel stove (they’re often single skinned which won’t take the heat that a wood burner produces). Finally, a chimney liner should not be used in place of a suitable chimney, if your chimney has internal or external damage, you must repair it even if you have a chimney liner in place.
To summarise, we have found that a flue liner will help to protect your chimney and save you money from potential repairs in the future but if you decide not to fit a flue liner ensure you meet the requirements of Document J Building Regulations.
How Often Should You Sweep a Chimney
Sweeping your flue liner is an essential part of maintaining your stove or fireplace. The best times to have your chimney swept are just before the start of the heating season and then again after you've stopped using your stove which is usually after the Spring. Both HETAS and The National Association of Chimney Sweeps (NACS) encourage that you have your chimney swept at least twice a year when burning wood or bituminous house coal and at least once a year when burning smokeless fuels.
Regular sweeping of a flue helps to prevent blockages or debris that can put you at risk of a chimney fire. A professional chimney sweeper will also be able to look out for any other hazards you may be unaware of. It doesn’t matter the type of chimney you have, whether it be brick, clay, twin wall or a flue liner, they all need regular sweeping.
Who Should Sweep My Chimney Liner?
You should always contact a reputable chimney sweep to be sure you’re getting the best advice and service. The NACS and HETAS are reliable sources of chimney sweeps.
Will a Chimney Sweep Make a Mess?
Chimney Sweeps are usually very mindful of making as little of a mess as possible they are trained in the prevention of dust & soot escaping while they carry out the sweep. A little mess however comes with the territory especially if the chimney is blocked or it has not been regularly swept, under these circumstances, it is difficult to guarantee a mess-free job.
How Much Does a Chimney Sweep Cost?
The average chimney sweeping cost is approximately £80 but may vary, you also need to consider that sweeps may charge more if your chimney has abnormal blockages or hasn't been maintained properly; Source: Local Yorkshire Chimney Sweep.
