Chimney Relining - Introduction
Why do I need to reline my chimney?
Below is a picture taken looking down inside a 1960's chimney (see image 1). The original lime mortar liner that was smeared over the internal bricks has gone leaving an uneven passage of bare bricks for the smoke, in most cases only the internal plaster on the chimney breast holds the dangerous fumes in.
When using a wood burning stove the flue temperature is much lower than with open fires. The control of the stove allows you to stop the smoke inside the flue. Cooling smoke turns to creosote which can seep into the very structure of the chimney, making it impossible to clean properly, increasing the chance of a chimney fire. With all types of fuel, carbon monoxide is released when burnt.
Below is a picture of an unlined chimney after 2 years of use with a wood stove (see image 2). The tar is easily ignited and would cause significant structural damage
Fitting an appliance of any fuel type to this age of chimney without relining is very hit and miss and so, very dangerous.
Our unique experience of liner installation compliments the high level of quality that our products demand and ensures long lasting safe operation as should be expected in the 21st Century.
The soft clay bricks used in construction and the age of many of our local houses requires a certain standard of installation. Always remember deciding not to reline or to reline badly is putting the occupiers or neighbours at risk of fume inhalation or a house fire.
Relining a chimney properly enhances the efficiency of your chosen fire, gives you piece of mind and allows us to sleep at night.
What Type of Liner Do I Need?
Class 2 Chimneys
For certain gas and oil appliances (stoves, boilers etc.) a stainless steel flexible single skin liner with a minimum internal diameter of 125mm is required.
Class 1 Chimneys
For larger 'open' gas fires, a Class 1 stainless steel twin wall flexible liner with a minimum diameter of 175mm is required.
Wood burning/multi fuel stoves require a class 1 stainless steel twin wall flexible liner with a minimum flue diameter of 150mm (depending on stove size). For wood burning a 316 grade stainless steel is adequate. If coal is the intended fuel, 904 grade stainless steel is recommended.
Open wood burning/coal fires require a Class 1 liner with a minimum diameter of 200mm. Open fires with larger fireplace openings (usually freestanding grates) will need larger flue sizes calculated alongside the height of the chimney.
There are many types of liner, each designed, sized and graded for different requirements. To determine the exact flue product needed for your chosen appliance, always check the manufacturers' recommendations. Most old brick chimneys were built for small open fires and the internal flue size was usually 225mm x 225mm (one brick) square. The largest stainless steel flexible liner we can fit into a typical chimney as a standard reline has a 175mm internal diameter. Larger concrete/pumice flues can be added with further structural disturbance. In some cases, due to your existing chimney being undersized or badly built a unique method of installation will be governed by the age and style of property.
Inglenook chimneys, usually found in properties over 300 years old, were designed to cope with masses of heat and smoke produced by large open fires used for heating, cooking and in some cases for the occupiers' trade (baker, blacksmith etc.). The oversized flues do cause problems with modern living as, even when not in use, the chimney rapidly pulls air from your house. This may be fine in summer, but in winter an inglenook can remove all of the heat produced by central heating in a room every 10 minutes. The perfect answer is to add a smaller, more controllable fire that needs a greatly reduced flue size. We find that stainless steel flexible or rigid flue systems are best to use in inglenooks, as the method of installation allows the least disturbance to the ancient structure.
The main aim of insulating a flue is to ensure the unburned gasses (smoke) from an appliance reach outside without cooling and solidifying on the way, creating a sticky tar build up. With inglenook chimneys it is usually not practical to back-fill around the new flue using vermiculite, therefore an insulating wrap is used.
In properties with thatched roofs, it is necessary to use a rigid stainless steel chimney system that is supplied ready insulated. This will guarantee heat cannot be transferred through the brickwork, which can and does ignite the thatch.