Help & Advice: 
4" Ultraflex 316/316 Flexible Flue Liner
Ultraflex 316/316 Stainless Steel Flexible Chimney Flue Liner – HETAS Approved
Upgrade your chimney system with the Ultraflex 316/316 Stainless Steel Flexible Flue Liner, ideal for relining existing brick or masonry stacks. Made in the UK, this high-quality liner features a triple lock design and is built with 316 grade stainless steel on both the inner and outer layers for long-lasting durability and corrosion resistance.
Suitable for use with solid fuel, gas, and oil appliances, it is HETAS approved and designed to perform reliably under high temperatures—up to 600°C for solid fuel and 250°C for oil and gas.
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35-year guarantee (lifetime under certain conditions*)
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Triple lock construction – crush and corrosion resistant
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Suitable for dried seasoned wood, gas, and oil
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Flexible, easy to install, and UK-manufactured
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Designed for relining brick/masonry chimney stacks
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Not to be fitted directly to the appliance
Please Note: Connect to the appliance using a short length of vitreous or 316 stainless steel pipe, ideally with a clean-out door for sweeping.
| Area | Delivery | Order Value | Price (ex VAT) |
|---|---|---|---|
| UK Mainland | Next Day* | Below £150 Net | £15.00 |
| UK Mainland | Next Day* | Over £150 Net | Free |
| Scottish Mainland | 1-2 Days | Below £150 Net | £15.00 |
| Scottish Mainland | 1-2 Days | Over £150 Net | Free |
*Orders must be placed by 2pm for next-day delivery. Deliveries are made Monday to Friday during regular working hours. Orders placed on weekends, public holidays, or bank holidays will be dispatched the next working day.
Pallet Delivery
Some items incur a £50.00 (ex Vat) pallet delivery charge due to their weight and size. This will be calculated at checkout. Also listed below.
| Product | Incuring Limit | Delivery |
|---|---|---|
| All Stoves | All Stoves | 2-4 days |
| 4" & 5" Flue Liner | 16 metres & Over | 48 hours |
| 6" Flue Liner | 13 metres & Over | 48 hours |
| 7" & 8" Flue Liner | 2 metres & Over | 48 hours |
| Vermiculite | 10 bags or more | 48 hours |
| Garden Stove | Per item | 48 hours |
All Pallet deliveries are curbside only. Some orders, especially those containing stoves, may arrive in multiple deliveries due to different suppliers, stock availability, and logistics.
For more information, please visit our Delivery Information page.
Internal Diameter: 100mm
External Diameter: 105mm
Various lengths of flexible liner are available (up to 40 metres).
- Made of 316 grade Stainless steel inner and 316 outer (Triple lock).
- Suitable for burning the following fuels: dried seasoned wood, gas, oil.
- This liner comes with a lifetime guarantee* (conditions apply).
- Normal operating temperature of up to 600°C for solid fuel and 250°C for Oil and Gas.
- HETAS approved product.
- Manufactured in the UK.
- Corrosion and crush resistant.
At Flue Finder, customer satisfaction is our priority. You can return unused items within 14 days of receipt, except for Stoves and cut-to-length Flue Liners (including liner kits).
If your goods are missing, defective, damaged or not as described please contact info@fluefinder.co.uk.
To initiate a return, please email us at returns@fluefinder.co.uk. We will send you a returns form and the return address.
Important: Returns must be reported in advance.
For more detailed information on the returns process and conditions, please visit our Returns Page.
*Stoves are non-returnable*
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What Our Customers Say
We value our customers' feedback and are proud to share their experiences with FLUE FINDER. Here’s what some of them have to say:
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Alex T
Just placed my first order on the new site and I’m impressed. Everything was easy to find, and the whole process from browsing to checkout was seamless. Looking forward to receiving my order!
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Julie
The new website is fantastic, much faster and more user friendly. Found exactly what I needed and got my confirmation email instantly. Great job!
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Martin
Love the layout of the new site. Everything is clearly explained, especially the technical details. Makes ordering the right parts so much easier.
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7" Ultraflex 316/316 Stainless Steel Flexible Flue Liner
£24.82 to £744.77 Excl. VAT
£29.78 to £893.72 Inc. VAT
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