Chimney linings and why?
Understanding the terminology associated with the lining a chimney
1) FLUE - The flue is the passageway through which the products of combustion travel to the outside from the stove.
2) CHIMNEY - This is the structure surrounding the flue/flues.
3) FLUE LINER - The material used to from the flue.
4) STOVE PIPE - The pipe connecting from the appliance to the flue within the chimney
For a stove to work successfully it must be connected to a sound and properly sized flue.
The purpose of a chimney is to remove the products of combustion from the appliance to the outside, without causing harm to the occupants or risk of setting the house on fire.
Operating a stove at a low temperature for long periods, or cold air leaking into the flue, will cool the flue gases down and affect the performance of the chimney. A stainless steel liner improves chimney draft by promoting hotter gases in turn a good draft improves fuel efficiency through more complete combustion.
Before flue liners were ever manufactured flues were usually parged on the inside with mortar. This parging over a period of time would have deteriorated from the corrosive properties within the flue gases, resulting in deterioration and leakage. This can usually be noticed by a sandy-powder like material falling down inside the chimney. That sandy material would be the plaster that has deteriorated over a period of time; also the mortar between the bricks will have deteriorated in the same way.
Chimneys are often constructed on the outside of the house and are exposed to the elements. This combined with the fact that there might be no insulation around the flue liners all adds up to a cold flue.
Please remember that stoves are efficient heating appliances and will produce anything up to 85% of heat from the fuel burnt into the room, unlike an open fire that can lose up to 95%. With little heat loss from an efficient stove, it is clear how essential to retain a reasonable flue gas temperature in order to achieve a consistent draw.
A properly lined and well insulated flue will produce a safe and efficient appliance. Unlined chimney flues can result in very costly rebuilding of the chimney and/or your home.
REASONS TO LINE
There are a number of reasons why a chimney should be lined or relined:
- Creosote or moisture are seeping through the chimney walls causing staining on the outside or inside the building.
- The flue is too large for the type of appliance being vented.
- The flue is leaking smoke and carbon monoxide into rooms or parts of the building.
- The flue is too cold, especially if it is on the outside wall, and not drawing properly.
- The chimney is old and was built before flue liners were ever manufactured.
- The flue liners are cracked due to a chimney fire, causing leakage.
- The flue liners were never installed properly and have gaps in between the flue liners.