Flexible flue liner in existing chimney

Your existing chimney, ready for a modern stove

If you have a brick chimney, a flexible stainless steel flue liner is almost always the smartest option: lining it for 80 to 130 euros per metre makes your old chimney gastight and tailored to your new appliance, without demolition work and in just 1 working day. Fully installed, you pay between 900 and 1,800 euros.

That is 800 to 1,200 euros less than building an entirely new flue, with the exact same certification and safety compliance. And because everything is fitted within your existing stack, your roof remains sealed and your facade untouched.

An old chimney is rarely useless: with the right liner, it becomes the most cost-effective flue system you can buy.

How we install the liner

1. Step 1: chimney inspection

   First, we inspect your chimney with a home camera inspection: diameter, cracks, obstructions, and soot deposits. This ensures the lining will fit perfectly and operate safely.

2. Step 2: sweeping and preparation

   The chimney is swept and any loose debris is removed. Sweeping is included as standard in our installation price, you pay no extra fees for it. A clean stack ensures the flue liner drops smoothly and prevents damage to the stainless steel.

3. Step 3: inserting and connecting the liner

   We lower the flexible liner into the chimney stack from above, tailored to your stove specs: 80 millimetres for pellets, 150 to 180 millimetres for wood. At the bottom, we create an airtight join with an adapter plate, while the top is fitted with a terminal plate and rain cowl.

   The liner hangs freely within the stack, allowing it to expand and contract naturally during every fire. The connection between the stove pipe and the chimney breast is finished with a decorative collar and heat-resistant sealant, sleek and draft-free.

4. Step 4: test burn and certificate

   Following a draught measurement and a test burn, you will receive your official certificate for insurance and warranty purposes immediately.

   Expect the whole job to take half to one full working day: we start the inspection in the morning, and by late afternoon your stove is burning on its new flue system.

When do you need a liner?

Almost always when converting from an open fireplace to a closed stove: the old chimney is too wide, causing flue gases to cool down and condense. A lining is also the standard solution for cracks, poor draw, or fitting a pellet stove into a masonry chimney. After years of disuse or a chimney fire, an inspection is essential first, as old damage is often hidden from view.

An open fireplace features a flue that is 25 to 40 centimetres wide, whereas a closed stove only requires 8 to 18 centimetres: without a liner, smoke cools down in that wide space, forming condensation and tar.

What is the cost of installing a flexible flue liner?

The lining material costs 80 to 130 euros per metre, and fully installed with adapters, top plate, and certificate, total costs range between 900 and 1,800 euros for an average home. A practical example: 6 metres of liner costs 480 to 780 euros in materials, plus the installation kit and half to a full day of labour.

For homes over 10 years old, a reduced 6 percent VAT rate applies, saving you around 150 euros on this example. Bends or narrow sections in the stack make the work slightly more complex, which our camera inspection highlights upfront. Should your chimney stack require structural repair, you can review potential scenarios in our chimney renovation price guide.

Liner or a brand new flue pipe system?

If the chimney is irreparably damaged or your stove is placed in a new spot, we install a twin wall flue system through your roof or exterior wall. During the chimney scan, we present both options side-by-side with fixed pricing, allowing you to decide based on clear facts.

Single wall flexible vs double wall smooth bore?

Flexible liners come in 2 distinct grades. The single wall version is an entry-level option for dry wood smoke in chimneys with strong natural draught. The double wall smooth bore liner features a smooth interior lining that reduces soot buildup and improves airflow, making it the industry standard for pellet stoves and intensive burning.

Quality built to last decades

We work exclusively with 316 grade stainless steel flexible liners, double-walled and fully resistant to acidic pellet and wood combustion gases. This includes a 10-year warranty and an expected lifespan of 25 to 30 years, provided it is swept once a year. Technical compliance guidelines can be found on the Buildwise standards page.

Itemised, transparent quotes

Your quote is always fully itemised: liner per metre, each bend and adapter listed separately, with labour and finishing costs on their own lines, clearly showing applicable VAT rates. This allows you to compare our rates fairly and know precisely what you pay upfront.

This approach is core to our stove and flue quotation service, delivering a fixed price within 48 hours of site measurement. Standard components are kept in stock, meaning installation typically takes place within 2 to 3 weeks of your approval.

After installation

A flexible liner is just as easy to sweep as a rigid pipe. We can include it in your annual chimney sweep or combine it with our combined stove and flue service.