One often contentious issue when it comes to chimneys is whether or not they need lining when fitting a solid fuel burning appliance.
While it sounds like a relatively simple question, sometimes you will find you get a different answer from everyone you ask! However, beware that there are a lot of misconceptions around chimney lining, including whether or not they are a legal requirement and what their exact purpose is.
So, we thought we would try to set the record straight. In this guide, we collect all the facts and information you need to know to finally provide an answer to the question, “does my chimney need a liner?”
What Are The Chimney Liner Building Regulations?
When it comes to your chimney, there is one major piece of legislation that needs to be referred to called ‘Document J’. The current version was introduced under building regulations in 2010, and covers the building work and installation surrounding all domestic combustion appliances - including wood burning stoves.
You can see Document J for yourself here.
It is a long document, so you would be forgiven for not wanting to read through it yourself. So, here are some of the main points that relate to the question of whether you need to line your chimney:
- “Combustion appliances shall have adequate provision for the discharge of products of combustion to the outside air” (J2)
- “New masonry chimneys should be constructed with flue liners and masonry suitable for the intended application” (1.27, page 22)
- “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 an appliance, the flue and chimney should be checked and, if necessary, altered to ensure they satisfy the requirements for the proposed use” (1.36, page 24)
Now, what does this mean exactly?
Confusion often arises around chimney lining because nowhere in the document does it specifically state whether a chimney liner is legally required. Rather, it states that a chimney must be in good working condition so that it safely removes all combustion fumes without risk of leaking them back into the house.
For many chimneys, the safest, easiest and most cost-effective way to guarantee this is to install a stainless steel flexible flue liner.
- All chimneys are required by law to be in good working condition.
- Lining your chimney is the best way to ensure this.
- Check Document J for full chimney regulation details.
Why Do You Need to Line a Chimney?
Let’s move onto the next misconception which is often around why you need a chimney liner at all.
The most common reason most people think they need to line their chimney is to prevent smoke from leaking out - and this is 100% true. A huge reason why you would need to line your chimney is to protect your home from carbon monoxide fumes.
However, there are more reasons why chimney liners are a good investment for your flue. Here are some of the main ones:
- Improved efficiency. Steel chimney liners retain heat better than brick, which improves the draw of gasses, resulting in better efficiency for your stove
- Cleanliness. Stainless steel liners also reduce the amount of creosote build-up. Creosote is almost impossible to remove, so keeping it away from your chimney walls is very helpful.
- Reducing chimney size. It could be your chimney is too wide for your stove to operate at its best. Installing a flexible flue liner can help reduce the size, which also improves efficiency.
- Lower risk of chimney fires. Installing a flexible flue liner helps to reduce the amount of soot and tar build up, which in turn reduces the potential for chimney fires starting
- Easy to install. Today’s flexible flue liners are so easy to install, it isn’t a lot of extra hassle to add the extra precautionary step to your flue system.
There are many reasons why you would choose to line your chimney. Safety, efficiency, cleanliness and even convenience all make fitting a flexible chimney liner a good choice, whether it is legally necessary or not.
Does My Chimney Need a Flue Liner?
While fitting a chimney liner does have plenty of benefits, you might still like to know whether your chimney actually needs one.
Let's look into the history of chimney liners to clear a few more things up.
For houses built before 1965, there were no regulations in place for lining chimneys. They were often built from brick or stone and commonly experienced faults that led to carbon monoxide fumes leaking out into living areas. In 1965, this was corrected with regulations that stated that new chimneys must be lined with clay or concrete.
Many chimney liners you can buy today are made from flexible stainless steel which is versatile, strong and durable. But, your chimney may already be lined with clay or concrete if it was built after 1965.
If this is the case, you might think you don’t need to install a new flexible chimney liner at all - and you might be right. However, you will need to have a qualified and HETAS registered inspector confirm that the clay or concrete liner is still fully intact and does not pose any risk of leaks. If it is deemed unsafe, it will require relining with a new flexible flue liner.
For many people, they choose to install a stainless steel flue liner even if they have an intact clay or concrete lining. This is because they are more reliable, efficient and offer extra peace of mind against carbon monoxide leaks.
If you live in an older property that pre-dates 1965, a new chimney liner is at the very least a good idea. As there was no requirement for chimney lining when these properties were built, it is likely that they pose a safety risk by today’s standards. If the chimney hasn’t been inspected in recent times, it is vital to enquire with a qualified expert on whether a new liner is needed.
- Houses built after 1965 may already have concrete or clay liners.
- Older properties will probably need a new liner installed.
- If your existing chimney liner is damaged, it will need fixing or replacing with a new one.
Do you need more help or advice regarding lining your chimney? Feel free to contact us for a friendly chat about your chimney lining requirements.
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