The flue is the part of the installation nobody sees and the part that decides whether the stove draws, stays clean and stays safe. An existing stack gets a flexible stainless liner sized to the appliance, sealed at the top with a proper cowl and closed off at the bottom with a register plate. Where there is no chimney at all, we build one: an insulated twin wall system up the gable or internally through the roof, set out so the terminal ends up in clean air rather than in the lee of a ridge.
316 grade for wood, 904 grade where smokeless fuel is the main fuel, sized to the appliance outlet rather than to the stack.
Insulated twin wall flue where there is no chimney, run externally up a gable or internally and out through the roof.
A sealed register plate with an access hatch at the bottom and the correct terminal and cowl at the top.
Every flue we fit can be swept from the room without dismantling anything, because it will need sweeping every year.
In practice, nearly always. An old stack was built to take the volume of an open fire, so it is far too big for a stove outlet, and a flue that is too large runs cold, draws badly and condenses tar. A liner brings it down to the right size, seals any leaks between flues and gives you a smooth surface that can be swept. There are sound masonry flues that pass a test without a liner, and they are the exception rather than the rule.
The grade of stainless steel. 316 is the standard grade and is fine where wood is the fuel. 904 has a higher nickel and chromium content and stands up far better to the acidic condensates that smokeless fuel produces, which is why we specify it wherever smokeless is going to be burned regularly. Liner guarantees are usually longer on 904 for the same reason.
A correctly specified liner, burning dry fuel and swept annually, should give you many years and comes with a manufacturer guarantee to match. What kills liners early is wet wood, smouldering a stove that is too big for the room, burning house coal in a 316 liner and skipping the sweep. None of those are the liner's fault, and all of them are avoidable.
A twin wall insulated flue system, which is a complete chimney in its own right. It can go up the outside of the gable wall, which is quicker and cheaper and leaves the flue visible, or internally through the ceilings and out through the roof, which is neater inside and more work. Both need the terminal to finish at the correct height above the roof, and both are fully notified and certificated the same as any other install.
Yes, when it is installed to the manufacturer instructions. Twin wall flue has an insulated jacket and a published distance to combustibles, and where it passes through a floor or a ceiling it gets a firestop plate and a properly framed opening keeping timber the correct distance away. Where it passes through a habitable room the sections are usually enclosed in a boxed casing with ventilation as required.
Not until the stack is sound. A liner does not hold up a chimney, and there is no point dropping one into brickwork that is cracked, spalled or missing its haunching, particularly on a coast where wind and salt do the damage faster. Repointing, rebuilding the top few courses or renewing the flaunching is often part of the job, and we will tell you at survey if that is what yours needs.
Send a photo of the chimney breast and David will come back with a price.