Chimney Lining

FLUE LINERS

A flue liner is a gas tight flexible steel tube that carries the flue gas from the stove to the chimney top.

When fitting a woodburner to a brick chimney we always use a flue liner, as due to the much smaller heat output to the chimney, without a liner there is the danger on a very cold night of a cold stone chimney failing to keep the draw, dropping cold air into the stove from above. This is how smoke and carbon monoxide can enter a room from a woodburner.

As an open fire puts much more heat into the chimney due to being much less efficient, it does not need a liner.

When the woodburner is used properly the flue liner keeps the whole house safe and allows efficient operation.

FLUE LINER INSTALLATION

We install liners from the chimney top, either using ladders, a cherry picker or scaffolding for access. We use ropes and harnesses whenever required.

The liner is then connected to the stove with a solid black flue pipe, the chimney is sealed around the pipe the bottom with a metal plate, and capped off at the top with a cowl fitted with bird guard.

We use heatproof spraypaint to finish off all metal parts in the fireplace, this gives a lovely uniform finish.

USEFUL INFORMATION

There are two liner choices available - Twenty Year 316L, for wood burning, and - Twentyfive Year 904L, for coal type fuels as well.

Coal can be burned with a 316L liner, but for no more than 5% of the fires. A coal burn should always be followed with a hot wood burn.

The 904L is made of higher grade steel so has a longer service life, but with good use the liners should far exceed the time stated.

316L and 904L are types of steel alloy, all liners are made from one or other, so the quality is in the construction and thickness of the material.

We have studied and tested premium brands of liner and found Technoflex 316L and 904L liner to be the best for these reasons:

We conducted these practical tests to compare liners.

The stand on test:

  • Technoflex - can be stood on without collapsing
  • Duraflue - collapsed and split
  • Multiflex - collapsed
  • Ebay - Budget collapsed and split

Beyond the bend radius test:

  • Technoflex - Folded without splitting, the hardest to get round a chimney bend
  • Duraflue - Split
  • Multiflex - Folded without splitting, the easiest to get round a chimney bend
  • Ebays Budget - Split easily

Smoke testing a crushed liner (crushed almost flat with breeze-blocks!):

  • Tecnoflex - Pass
  • Duraflue - Fail (visibly split)
  • Multiflex - Pass
  • Ebays Budget - Fail (visibly split)

Weight (thickness) test:

  • Technoflex - By far the heaviest
  • Duraflue - Light
  • Multiflex - Medium
  • Ebays Budget - Medium

Construction:

  • Technoflex - Twin coil wrap (standard)
  • Duraflue - Twin coil wrap with smooth inside (good)
  • Multiflex - Twin coil wrap (standard)
  • Ebays Budget - Single coil wrap

NOTE - Since selecting Technoflex in 2012 we have fitted thousands of meters of it, and it really is one of the hardest liners to install, so we were delighted when it became the first 316L liner to have a 20 year warranty. Proving that it is the best liner available!