Thermal insulation for chimney pipes is a prerequisite due to which it is possible to extend the life of the entire heating structure and at the same time reduce heat loss in the house. The material and method for pipe insulation is selected depending on the type of chimney (stone, steel, ceramic, asbestos-cement).
Why insulate the chimney
Chimney insulation is important for several reasons:
- A pipe that removes hot smoke from a room has an elevated temperature during working hours. From outside it is affected by low temperatures, precipitation. The temperature difference outside and inside sooner or later leads to the destruction of the material, whether it be brick, metal, asbestos.
- The pipe insulated from the outside is not inclined to accumulate condensate on its walls, which is a mixture of acids and water. The absence of condensate excludes icing, metal corrosion, weighting of the roof structure, and destruction of the pipe.
- The insulated chimney pipe allows you to save heat in the room, reduce fuel consumption and increase the efficiency of the heating system.
Inside the insulated pipe, less soot accumulates. As a result, the maintenance of the flue system is reduced, the family budget is saved.
Materials for insulation
Choosing a heater to conduct insulation for the chimney, it is important to pay attention to its properties. The material must have good thermal insulation characteristics and not be combustible. It is desirable that the insulation has a low hygroscopicity.
The best options for insulating a chimney in a bathhouse or a house are several types of materials.
Mineral wool
It is a fibrous material that has an air gap. Thanks to a special treatment, mineral wool does not ignite, while retaining its shape even when exposed to high temperatures. It is inexpensive.
Mineral wool insulation has several disadvantages:
- susceptibility to deformation over time;
- ability to absorb moisture.
Mineral wool is less and less used as an external insulation, since it is necessary to isolate well exposed areas, put it in a hard shell (frame).
Basalt wool
This insulation material has the following technical characteristics:
- Low thermal conductivity, which can be compared with polystyrene, cork materials, rubber.
- High fire resistance. Basalt wool can withstand temperatures of more than +1000 ° C while not losing thermal insulation properties.
- Excellent waterproofing properties. Water is not able to penetrate the basalt wool.
- Resistance to mechanical influences. In the production of basalt wool, the fibers in it are alternately arranged vertically and longitudinally. This design allows you to withstand fairly high compressive loads.
Basalt cotton wool is produced mainly by slabs. Therefore, to insulate the chimney, you will have to build a special external duct.
Kaolin plates
Kaolin is absolutely safe for human health. It does not emit toxic substances into the atmosphere even with high heat. Kaolin stoves are resistant to fire, so they can be used to warm chimney flues, stoves with open fire.
It is easy to work with viburnum plates, as they are light in weight. The peculiarity of the insulation is that with a minimum density, its insulation capacity is quite high. And this means that when performing repair work, it is possible to maintain the usable area around the chimney indoors.
Roll Filters
Externally, they are cylinders, the outer part of which is made of foil material, and the inner one is made of foam. Roll filters are especially good for galvanized steel pipes. Such a heater withstands high temperatures, is resistant to fire and high humidity. The only condition for the installation of roll filters is reliable sealing of the joints in the upper open part of the roll from atmospheric precipitation.
The nuances of self-insulation of the chimney
It is recommended to adhere to such rules when insulating the chimney of a gas boiler or an open fire furnace:
- The outer, open part of the pipe is always and necessarily insulated.
- Pay attention to the area of the pipe in the transition between the roof and the floor of the attic. It is believed that in the attic in winter it is relatively warm and there is no need to insulate the pipe. However, at strong low outside temperatures, condensation may accumulate in this part of the chimney.
Work is best done together to insure each other in the open space of the roof.
Chimney insulation principles for different types of chimney
Insulation of the chimney from a gas boiler or open-fire stove for beginners should be done in accordance with a step-by-step guide.
Galvanized steel pipe solid fuel or gas boiler
For metal and iron pipes, the most optimal option is the use of a special shell-sandwich made of stainless steel or galvanized steel with an inner layer of foamed thermal insulation. They are selected according to the diameter of the existing pipe and simply put on top of the chimney. Then isolate the joints if necessary.
When installing such cylinders, you should adhere to the principles of the device inside and out:
- Inside the building, experts advise arranging pipes along the smoke path - insert each lower pipe into the upper one. Press joints with clamps.
- In the zone of the chimney exit to the street and from the side of the roof, the insulation is collected along the condensate. - the upper part is inserted into the lower.
For the attic area, it is advisable to use a sleeve coupling made of rubber and a heat-insulating layer. Before insulating the metal chimney pipe, it is necessary to fix it well so that the heat-insulating material does not exert strong pressure on the structure.
Asbestos pipe insulation
The best option for insulation is mineral wool or brick.
If we are talking about brick, you must first make a protective casing for the asbestos pipe, the diameter of which exceeds the cross section of the chimney by 12 cm. First, all sections of the casing are assembled around the pipe by 1.5 m. Each part of the casing is filled with beaten bricks. The joints of the sections are fully sealed.
To insulate the asbestos-cement pipe with mineral wool, it tightly wrap the chimney and tighten it with clamps in steps of 50 cm. From above, the winding from the insulation is well waterproofed. The waterproofing material also needs to be wound well around and pulled together with clamps.
Brick chimney insulation
A brick pipe can be insulated in two ways:
- Plastering. A special layer of plaster is laid on a reinforcing mesh. Thanks to this layer, it is possible to reduce heat loss by 25%. Before performing work, it is necessary to close the furnace gas valve of the chimney (if we are talking about a gas boiler). Plaster should be applied in 3-5 layers.
- Cladding a brick pipe with basalt wool slabs.Plates can be planted on special building umbrellas. They are also plastered from above. Squares of basalt wool should be laid according to the type of brickwork, with an offset. This reduces the likelihood of cold bridges on the chimney outside.
When insulating the chimney pipe, attention is paid to the joints. These areas are a potential risk to the pipe. Condensation forms through the cold bridges, which later leads to icing of the ceiling structure and increased heat loss.
