Choosing the correct liner size for NEW chimneys.

“New masonry chimneys should be constructed with flue liners suitable for the intended application”.

This statement from Building Document J is critical; however, a common issue is that many newly built chimneys rely on flexible liners to allow a stove installation, because the typically 225mm clay/concrete system specified has too wide a diameter for the appliance.

The usual solution is to drop a steel flexible steel liner down, incurring additional time and expense (up to £1,000 per property) and contravening Building Document J.

Document J clearly states: “Flexible flue liners should be used only to RELINE a chimney and should not be used in a new chimney”.

Schiedel Chimney Systems Isokern and ceramic liners start at 150mm and 160mm diameters respectively, removing the need to install a flexible liner, saving both time and money.


  • Liners start at 160mm so no need for an additional steel liner
  • Ideal for both new build or relining existing masonry chimneys, where a rigid steel chimney would require inspection hatches
  • The most cost-effective way of installing a chimney into a newbuild property
  • Suitable for gas, oil, solid fuel,  biomass and pellet stoves
  • Suitable for both high and low temperature applications
  • Certified to EN1857 1 & 2 with the designation T600 N1 G

Click here to see the range in the Shop.

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