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Twin wall flue system

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If you are installing a new heating appliance, such as a wood-burning stove, gas coal-effect fire or an oil boiler, you will probably need an insulated flue system, you certainly will if you do not have a brick chimney stack. Twin wall systems can be constructed to produce a safe chimney system for your appliance.

Twin wall flue pipes are suitable for the creation of both indoor and outdoor flues and they can be used to pass through roofs and floors. Our double wall flues are suitable for use with wood, coal, gas and oil appliances. Our Twin wall flue system is also perfect for biomass boiler installations.

The outside diameter of twin wall flue pipes is 60mm more than the inside diameter. So a 150mm pipe has an outer diameter of 210mm.

Our twin wall flue is a class 1 insulated flue system manufactured in Europe. This double wall flue is suitable for use with wood, coal, gas and oil appliances. Made of stainless steel - the twin wall flue is also perfect for biomass boiler installations.

  • Push fit jointing system - secures using a locking band
  • 30-year warranty
  • 30mm of insulation
  • The internal joint system prevents moisture draw through
  • HETAS listed for use in solid fuel applications

All our pipes are supplied with the necessary locking bands, free of charge.

A twin wall flue pipe is a metal tube (flue) insulated with approx. 12 inches of insulation (two layers of stainless steel with insulation between). Stainless and black powder-coated systems are fully interchangeable. All of our black Twin Wall Insulated Flue products are a true MATT black finish.

Insulation is necessary to keep the gases hot. If you were to use non-insulated flue pipe for the whole of your chimney, then the gases would likely cool too much and start to slow down rather than rising, with this causing the smoke underneath to “dam”. This might cause the smoke below to exit out of the vents in your stove instead of the top of your chimney.

Cooling gases also form condensation, which collects on the inner walls of the flue and runs down into the stove (mixed with soot it is a disgusting brown liquid).

We have a wide selection of Insulated Flue Systems in 5, 6, 7 and 8-inch pipes , including twin wall insulated flue pipes, cowls, flashing and bends to ensure you can build a complete twinwall flue system.

All our double-walled flues are fully approved by HETAS, and have the EN-1856-1 test certificate.

We can help you design your flue system!

You can send us a diagram, with dimensions to or click to fill in our free FLUE DESIGN SERVICE FORM. And a member of our trained technical team will send you a complete quote for your twin wall flue system.

For information about the legislation, please see our blog about flue regulations