If you’re planning to install a wood-burning stove, fitting a chimney liner is highly recommended for safety and optimal performance. Chimney liners form a smooth, uninterrupted path for smoke and combustion gases to escape your stove efficiently. Lining your chimney can prevent the build-up of creosote and tar while also protecting the masonry from heat damage. 

In this DIY guide, we’ll walk through the complete process of installing a chimney liner step-by-step. We’ll cover measuring your chimney, choosing the right liner, preparation steps, installation, connecting to your stove, and finishing touches. Let’s get started! 

What is a chimney liner?

A chimney liner is a flexible stainless-steel tube that runs from the top of your stovepipe through the chimney flue. It protects the masonry chimney structure from the by-products of burning wood, including harsh smoke, condensation, and corrosive chemicals. Liners are made of durable, long-lasting 316-grade stainless steel. They’re also available in 904-grade and W3G Ecodesign-ready stainless steel. 

Chimney liners improve draught for cleaner burning, prevent leaks through damaged flue walls, and reduce the risk of chimney fires. Though not always required, liners are recommended in the UK to ensure safety and optimise stove efficiency. 

Choosing the right liner 

Choosing the proper liner diameter is crucial for stove performance. The liner should be as close as possible to the stove’s flue outlet size. For example, if your stove has a 150mm flue collar, choose a 152mm or 155mm liner. Never downsize the flue diameter too much. 

Measure the height of your chimney in advance so you can buy a tailored liner length. Purchase a little extra as a buffer. Liner kits include the stainless-steel tube, insulation wrap, adaptor plate, and top cap. Proper insulation helps maintain flue gas temperatures. 

You’ll also need:

  • Rope – at least 2x chimney height
  • Grinder with metal cut-off wheels
  • Hammer, screwdriver, tap measure
  • Gloves, goggles, mask, protective clothing 
  • Ladder/scaffold as needed 
  • Fire cement, bolts, seals 
  • Stove pipe sections if connecting stove 

Preparing the chimney

Start by thoroughly cleaning the chimney using rods and brushes. Then, drop a weighted rope from the top and mark the length on the rope. Add at least 460mm for installation wiggle room. Order your custom-length liner. 

Once the liner arrives, put on protective gear. You’ll need two people for this job. Attach a rope to the top of the liner. Feed the rope down the chimney while the person below guides it through. This stops the liner from getting stuck. 

If necessary, use a grinder to cut the pot flush to fit the liner top. Clear any remaining debris with the rope. Ensure the liner joints are tight and aligned. 

Installing the liner

Feed the rope back down the chimney. Carefully feed the liner down as the helper above steadily pulls up the rope. Using the rope, align the liner centrally in the flue. Have the person below guide it down, watching for snags. 

When the top emerges, fit the cap and pull the liner up to the desired height based on weather exposure. Secure with high-temp sealant/fire cement and bolts through the adaptor plate. Attach the stove-pipe adaptor and seal with fire cement. 

Connecting the stove 

Position the stove on spacers as required and mark the wall for drilling. Attach the first stove-pipe section to the collar with high-temperature silicone or fire cement. Build more sections to reach the liner adaptor, maintaining proper rise and elbow angles. 

Use self-tapping screws on all joints, sealing with fire cement. Install wall thimbles and supports. Ensure joints are airtight – leaks can be dangerous! Extend the liner above other chimney openings if needed. 

The finishing touches

Seal any gaps around the liner with fire cement or high-temperature silicone. Double-check that the joints are tight and properly sealed. Perform a smoke test by lighting paper below to check for leaks. 

When ready, light your first small fire and confirm the draught is correct, as the stove manufacturer specifies. Cure the new stove slowly over 3-4 initial fires to harden the paint thoroughly. 

Use properly seasoned wood and follow maintenance guidelines like annual chimney sweeping. Enjoy your new lined chimney and cleaner, warmer burns!