FuranFlex25 Black

FuranFlex25 Black

FuranFlex25Revolutionary change in the field of chimney lining

T200 P1 W 2 OXX
EU classification (ETA-12/0346)
Certification temperature: 200 °C
Maximum heat resistance: 500 °C

What is FuranFlex25 Black?

FuranFlex25 Black

FuranFlex25 Black is the only method, by which chimneys of any shape, dimension and length can be lined with joint-free airtight liner of steel hardness composite material that is resistant to corrosion, flames and heat. FuranFlex25 Black is a Glass Fibre Reinforced Thermosetting Resin lining and is suitable for gas and oil heating applications.

The liner is installed into the chimney as a flat flexible hose, inflated with air at only 0.2Bar minimising any stress on the existing structure. The liner is then “steamed”, this process begins a reaction in the resin and once the resin reaches 100° Celsius it sets as hard as steel. Once this reaction has taken place the liner is cured and ready to use.

FuranFlex25 Black has been tested by many leading European accredited testing houses including BSRIA in the UK and is CE approved. FuranFlex25 Black gives a highly corrosion resistant lining, totally waterproof and gas tight and tested to 400° Celsius. FuranFlex25 Black linings have been used for over 12 years in 27 European Countries and well over 3,000,000 metres have been successfully installed with over 12,000 metres successfully installed in the UK over the last 24 months.

Only Kompozit’allUK factory trained and accredited engineers are allowed to install FuranFlex25 Black to ensure high standards of installation are maintained. FuranFlex25 Black is only 2.5mm thick and can be installed freestanding inside the chimney/duct or pipe. It can also be installed to mould to take the shape of the existing chimney/duct or pipe to maximise the cross sectional area of the chimney. This reduces the need to fit boost fans or chimney fans saving time, money and maintenance costs.

FuranFlex25 Black is available in diameters from 50mm to in excess of 1000mm and in one-piece lengths up to 100 metres. FuranFlex25 Black linings are usually installed in one day and the appliances can be used immediately after the lining is “cured”.

Why composite material?

FuranFlex25Black is made of thermosetting resin material with fibre glass reinforcement (composite) that has physical (steel strength) and chemical (acid-resistant, alkali-resistant) properties that are perfectly suited for lining chimneys. Its special resin composition guarantees high thermal resistance.

Row of houses

Why Choose FuranFlex25 Black Over the Alternatives?

  • Heatproof up to 400°C
  • Flexible diameters from 50 mm to 1000 mm +
  • Lengths of up to 100 m
  • One of the highest fire resistance ratings – tested and proven
  • Matches the precise shape and size of any ventilation system
  • Installation can take as little as four hours
  • Long life span with minimal maintenance
  • Fast and easy to clean
  • Independently quality tested and CE marked
  • Fully comprehensive 25-year guarantee
  • Supplied and fitted by our teams of factory trained, fully certified and accredited installers



FuranFlex25 is a waterproof and gas tight chimney relining system which normally only requires access at each end of the chimney for a quick, clean and speedy solution


FuranFlex25 has been used in many U & SE Ducts. It gives a smoother one-piece waterproof lining, and we can also recommend suitable replacement boilers and fan system to ensure efficient operation with condensate collection at the base. This will improve the efficiency of the heating system by approximately 33%


When lining a vertical riser there are no joints so no need for inspection hatches. This is very useful on existing twin-wall and single wall chimneys where there is no access to install inspection hatches to bring it up to current regulations. On horizontal sections there would still be a requirement to ensure adequate supports.

Why Choose an Accredited Kompozit’allUK Installer?

FuranFlex25 Black Installed

FuranFlex25 Black is fast and easy to install by engineers with the relevant training, skill and product knowledge. Kompozit’allUK engineers are factory trained and experienced to ensure your installation is completed within budget and timeframe, and subsequent maintenance issues are avoided.

Some independent, unlicensed installers may claim to offer FuranFlex25 Black solutions. However, we strongly recommend only working with a Kompozit’allUK registered installation partner.

Our partners have the equipment and training to provide accurate CCTV surveys and efficient installations. This is essential for you to get the right specification and size of lining. Each engineer and surveyor is required to renew their certification on an annual basis; keeping their skills and knowledge up-to-date.

Request a Quote

For a fast, no obligation quote, or for any queries about installation, please call 01622 717374 today, or send an email to inquiry@kompozitalluk.com.