The rules for installing a flexible flue liner

Flexible flue liner in focus

Flexible flue liner, also known as twin-wall, has smooth inner walls and can adapt to all configurations of connection.

Easy to fit and less expensive than rigid liner, it is often the preferred choice in renovation work, as it is particularly suitable where the chimney flue has offsets.

⚠️ Before lining, you need to 

·     Carry out chimney sweeping of the flue

·     Check the clearance of the flue using a cone with a diameter slightly larger than that of the liner

Other key points to bear in mind:

·     As with rigid liner, the angle of offset must be less than 45°.

·     The flue must be lined over its entire length

·     The masonry flue must be ventilated

·     An identification plate filled in with the liner's specifications must be fitted

·     The accessories must be compatible : a sealing plate and a cowl are mandatory

·     The sweeping tee must be made of stainless steel of the same grade as the liner and must have an access point to allow a sweeping brush through

·     A leak test must be carried out after installation, then repeated every 3 years.