The most appealing focal point in any room must be the fireplace. Be it an open fire, closed stove or room-heater, the leaping flames and glowing coals are the real heart of the home. However, for any fire to work successfully, it must be connected to a sound chimney and correctly sized flue. The functions of a chimney are to safely remove the products of combustion from the fireplace or appliance to outside without causing danger to the occupants of the house or setting the house itself on fire. A chimney works because hot air rises and always moves from high to low pressure. Factors such as running the appliance at a very slow rate or cold air leaking into the flue, will cool the gasses and affect the performance of the chimney. To keep the flue gasses warm, consideration must be given to the insulation value of the lining system chosen. In houses built since the introduction of the 1965 Building Regulations, all flues must be built with liners during their construction. This is usually done with clay liners, which should last the life of the building. However, in houses built prior to 1965, lining was less common. Flues were usually “parged” (rendered) on the inside with lime mortar. This parging suffers attack from acids and tars produced during combustion, and gradually deteriorates. The flue is then in poor condition, often leaking fumes or tars into the walls or other parts of the building. Sadly, many houses built since 1965 suffer similar problems due to badly installed flue liners and need further attention.
There are a number of reasons why an old chimney may need lining. For example you might find that the flue is leaking smoke and fumes into other rooms or parts of the building. Condensates or tar are seeping through the chimney walls causing staining, either inside or outside the building (a common problem with wood burning stoves) The flue is much too large for the type of fire or appliance being used. Or perhaps The flue is too cold, particularly if on an outside wall, and is not drawing properly. Before any new lining is installed it is essential to have the chimney thoroughly swept to remove all soot and tar deposits. This means with stiff polypropylene or steel scraper brushes. There are two distinct types of flexible metal liners available and it is very important to distinguish between them.
Solid Fuel Liners
This is a double skinned liner made from an extremely high quality stainless steel It is smooth on the inside, corrugated on the outside and must be installed the correct way up. It is specifically designed for relining flues for solid fuel and wood. Whilst stainless steel is a very tough material, it is still prone to corrosion due to the acidity of fumes from solid fuel, especially if condensation is present. Its anti corrosion properties are also reduced if heated above 900ºC for more than about 15 minutes, perhaps as the result of a chimney fire.
Gas and oil flue liners
A light gauge single skin liner, only suitable for closed gas fires and boilers, some inset fuel effect gas fires and kerosene oil appliances. It should never be used with solid fuel or wood burning
For further unbiased advice contact Yorkshire Stove Solutions
“We will never insist a liner is fit where it is not required”
3 Dale Close,