Can I install my own chimney flue liner?

Yes, it is entirely possible to install chimney flue liner yourself, especially if you have experience in building and DIY projects. However, there are some important considerations, which we’ll look at here.

Installing a flexible chimney liner is a more complex task that may require ladders or scaffolding for external access to your roof. However, it's still a manageable job that involves removing any chimney capping, dropping the liner down the chimney stack, or pulling it up from the bottom.

If you're confident in your building skills and comfortable working at heights, you can definitely attempt this project.

Tools & equipment required

You’ll need access equipment, such as ladders and scaffolding to get to the chimney.

If pulling the liner from the top , you’ll need a suitable length of rope.

A sturdy knife, tin snips or hacksaw will be required to trim any excess liner.

Pliers & screwdrivers will be useful for installing the cowl.

Materials required

In addition to the correct length & diameter of flexible flue, depending on your project, you may need some or all of the following:

• Chimney cowl
• Bedding mortar
• Backfill insulation
• Chimney register plate
• Stove pipe adaptor
• Fire cement /fire rope
• Nose cone (for pulling liner through)
• Smoke bombs

Installing a flue liner from the bottom.

One person should position themselves on the roof, while the other stands by the opening of the fireplace.

Next, the person on the roof will carefully drop a long piece of rope – longer than the length of the chimney – down the flue, with a weight attached to the end.

Meanwhile, the person by the fireplace will catch the rope and securely tie it to the top of the flue liner, making sure to attach a nose cone.

Back on the roof, the first person will then pull on the rope, hauling it up the chimney. The person on the bottom will assist by pushing when needed, ensuring a smooth and efficient process.

How to install flue liner from the chimney

Again, it's essential to have one person on the roof and another by the fireplace. This will ensure a safe and efficient installation process.

The chimney liner will need to be uncoiled and carried up to the roof. Next, you'll drop a rope down the chimney, just like before, but this time, tie it to the bottom of the flue liner. Make sure to attach a nose cone to the end of the rope to help guide it down smoothly.

Now, you can start feeding the liner down the chimney. Meanwhile, the second person should pull on the other end of the rope to assist and ensure a smooth descent.

Note:  Flexible liner must be installed in one direction so check for arrows showing which way to install it.

Beware of bends

If you have any bends in your chimney, you might find that the liner gets stuck at some points during the fitting process. If turning it and giving it a few different pushes and pulls doesn’t help, you could try reversing your method to either top-to-bottom or bottom-to-top installation. If you still find it gets stuck, it might be that you need to knock a hole in the chimney to help you push it through - which will need repairing safely, too.

Insulation and capping

The next step is to backfill any gaps between the liner and stack with vermiculite loose fill insulation and fit a suitable chimney cowl .

Safety and Legal Requirements

Remember to notify your local council's Building Control department, and they'll inspect and sign off on your work once it's complete. Alternatively, if you hire an installer approved by a Competent Persons scheme, such as HETAS, they'll test & sign off the project and provide you with a certificate.