Before you find out how to insulate a chimney, you need to study a number of factors that will eliminate the causes of damage and increase the service life of the exhaust pipe. Let's look at all these nuances together and find out how to insulate the chimney exhaust pipe of a residential building.
Why insulate a chimney - let's look into the details
The chimney is considered one of the most important elements of the heating or stove system of a residential building. In order for a metal pipe to function normally, it needs to be insulated. At first glance, this event may seem very simple, but before installing non-flammable insulation for the chimney, we advise you to familiarize yourself with certain recommendations and safety rules when working. The first thing you should do is study the reasons for installing protection on the pipe.
This part is often subjected to heavy loads: pressure and hot air. A lot of combustion products regularly pass through the chimney. Under certain conditions, the latter enter into chemical reactions with air and moisture. As a result, the corrosion process accelerates significantly, and this negatively affects the operation of the entire exhaust system of the house. The service life can only be increased if the chimney iron pipe is insulated. This will reduce the risk of chemical and mechanical corrosion of the element. All costs for the purchase and installation of protective materials will be fully recouped, because without them you will have to change the pipe, and this will cost many times more.
Before insulating the chimney, we suggest that you familiarize yourself with the main reasons for performing this procedure. Experts identify the 2 most dangerous factors that gradually destroy the pipe: chemical components and moisture. Moisture on the walls of the pipe is nothing more than condensation formed when flows of cold and hot air meet. Accumulating in large quantities, moisture contributes to the development of corrosion. The catalyst for this process is high temperatures.
The second dangerous enemy of the pipe is the aggressive chemicals that are formed as a result of fuel combustion. They can form active compounds of alkali, salt or acid, which seep into the pipe walls and contribute to the occurrence of chemical corrosion. The influence of destructive factors on the chimney, to one degree or another, depends on changes in the temperature of the walls of the pipe itself and the air flow that rises upward from the firebox. The lower the temperature of the first, the faster its walls are destroyed.
What are the advantages of a protected chimney
Installing a chimney pipe protection yourself provides several significant advantages. Firstly, it minimizes the influence of chemical compounds and moisture. The main task performed by the protective material is to raise the level at which condensation forms to the very top of the pipe cut. This can be achieved by increasing the temperature on the surface of the exhaust duct and reducing the temperature difference between the pipe and the steam flow.
Insulation for chimney pipes significantly increases their service life and service life. In addition, less time and money will be spent on system repairs. Reliable means of protection make it possible to completely remove dangerous chemical compounds from the stove. In addition, protection helps make the structure more resistant to winds and precipitation. Fire-resistant material reliably protects the upper part of the chimney in case of fire, preventing it from igniting. You can buy the required amount of protective agent at any hardware store at a low price. Moreover, if you install it yourself, you can save a decent amount of money.
Selecting insulation – basalt, steel or wood?
Before insulating a chimney pipe, we recommend that you familiarize yourself with the most effective materials that are best suited for this event. First of all, each of them has a high degree of thermal insulation. All the materials described below protect the chimney from external factors. Manufacturers offer a huge range of products that help make the chimney completely insulated and protected.
Answering the question: “How to insulate a chimney pipe?”, many experts immediately recommend installing protection based on basalt. This material is made from fibers obtained, in turn, as a result of the melting of gabbro-basalt. Basalt chimney insulation has excellent thermal insulation and high strength. Other advantages of such protection include:
- the ability to retain up to 90% of heat inside the pipe;
- the ability to allow moisture vapor to pass through;
- resistance to all types of corrosion;
- resistance to the formation of fungi and mold;
- vibration protection;
- ignition protection;
- environmental friendliness;
- resistance to UV rays.
Another popular method is to install a stainless steel casing. This product helps to increase the strength of the entire structure and protect the pipe from the influence of moisture and chemical compounds. The casing has a diameter slightly larger than the chimney pipe itself, so it is installed on the outer walls of the latter. The resulting space is filled with any quickly hardening agent. For example, they are often used for this.
One of the simplest methods is the installation of wooden panels. They are made from a wooden frame, on top of which boards are mounted. Slate or other roofing material is attached on top of them. It is important that the “shell” of the shield and the roofing material of the house are the same. The space that has formed between the shield and the chimney must be filled with asbestos or felt. At the seams it is necessary to lubricate with a thick layer.
The last of the most popular means of protection are cinder concrete and reinforced concrete slabs. This insulation of the chimney from the outside allows you to achieve a good effect at low financial costs. When installing blocks, remember that the gaps between them and the chimney should be minimal. The free space is filled with mesh or steel wire. In addition, the gaps are filled with clay, sand or gypsum. We apply cement mortar at the joints between the slabs, and plaster will need to be applied on top of the slabs themselves.
Installation of protection - how to extend the service life
Chimneys in residential buildings in our country differ in design and the material from which they are made. The most common are brickwork, chimneys in the form of an iron pipe and asbestos-cement slabs. The insulation of a home chimney pipe directly depends on the material from which the latter is made. First of all, let's look at how to install protective material on brick chimneys. There are several options for this.
The first method is to apply plaster. To do this, attach a steel stack to the outside of the chimney. On top you will need to apply a layer of plaster at least 3 cm thick. Once the first layer is completely dry, apply a mixture of a small amount of cement, slag and lime on top of it. For more effective protection, apply a third layer of the same mixture. Once it dries, it will need to be sanded, puttied and painted.
The second method is based on the use of mineral insulation. To do this, you need to “put” several basalt sheets on the pipe. Asbestos-cement boards are attached to the sheets from the outside, and plaster is applied on top of them. Although the second method is more complex, it provides several advantages. Firstly, heat losses of the heating system are reduced by 2 times. Secondly, the likelihood of condensate accumulating on the pipe is reduced. Thirdly, the strength of the chimney increases several times.
If you are considering how and how to insulate an asbestos-cement chimney pipe on the street, then for this you will need to use this method. First, make a metal casing. Take a sheet of galvanized steel and wrap it around the chimney. If the chimney is very high, then several sheets will need to be wrapped around it, laid in the shape of a cylinder. In this case, each of the top sheets should “overstep” the bottom sheet by 10 cm. The gap between the casing and the chimney should not be more than 6 cm. Fill the space with mineral wool, compacting the material tightly. Pour cement mortar over the mineral wool.
Chimneys made of steel can be protected using a separate iron pipe of larger diameter. In this case, the difference in width between the pipes should not exceed 3 cm. Fill the space with basalt wool. Just as in the previous case, carefully compact the material between the pipes.
How to insulate a chimney in the attic of a residential building
In addition to installing protection on the outside of the building, chimneys often require additional measures to be taken in the attic. This is due to the fact that in some houses there is no heating in this part. To protect the attic part of the chimney, we recommend using wooden panels. They are ideal for such work, since precipitation does not reach the attic. Therefore, water will not get on the wooden frame. First, make a frame. Take several wooden blocks, the length of which should be no less than the height of the chimney in the attic.
After this, make the shields yourself from boards treated with transparent protective varnish. Connect the beams to the boards to make a tall box. Install the structure around the chimney. The distance between the two products should be no more than 3 cm. Fill the resulting space with felt and sand, then fill the upper part with mineral wool. At the end, all that remains is to prime the shield and apply paint to it. If the attic is not used for living, then you can do without decorative design of the structure.
Insulation of the chimney pipe has become a significant problem with the advent of modern stoves with iron and asbestos chimneys. For classical stoves, chimneys were always made of brick. They were laid out and plastered in a certain way to avoid negative aspects from overcooling the chimney.
When installing a new stove or reinstalling an old one, you need to know how to insulate a chimney pipe with your own hands. This is not difficult to do. The main thing is to know the technology, choose the right materials and follow some rules.
There are several negative aspects that can be prevented by properly insulating the chimney:
- Preventing destruction of the chimney itself.
- Preventing roof destruction.
- Protecting the building from fire.
Combustion products contain many aggressive volatile substances. Some of them, when mixed with water, form aggressive substances - acids. Moisture condenses on the cold walls of an uninsulated chimney pipe, and acids destroy the structure. This acts especially quickly on metal pipes, which literally corrode over several heating seasons.
Note! High-quality thermal insulation of metal chimneys extends their service life by 2-3 times.
In addition to the destructive effect on the walls of the smoke channel pipe, condensate clogs the internal lumen when operating stoves in the long-term burning mode. A black, viscous mass with a specific odor flows from the walls of a cooled chimney and poisons the life of the owners. The pipe must be cleaned frequently. This is a labor-intensive, unpleasant task.
During intensive use of the stove, which in our natural conditions lasts more than 3-4 months a year, the heated chimney pipe is constantly in contact with the cold roof. Temperature changes have a destructive effect on the roof of a building. Burnout or overheating of a chimney in severe frosts is perhaps the first cause of fires in the private sector.
High-quality thermal insulation prevents temperature differences between the hot combustion products of fuel and the wall of the chimney.
Steam, carbon dioxide and soot freely leave the chimney channels, leaving it dry. The roof remains cold. When a pipe burns out, additional layers protect the roof from hot gases and sparks.
But not every insulation can be used to thermally insulate a chimney pipe.
Types of insulation
- The following requirements apply to the insulation for the chimney pipe:
- the material must be available for DIY installation;
- it must be non-flammable;
it should be suitable for insulating your type of chimney.
Correctly selected insulation for a chimney allows you to make the pipe as airtight as possible, protected both from strong heat, the characteristic acid-alkaline environment, and from external influences and atmospheric factors. Mostly, insulation of the chimney pipe is carried out at the stage of its installation, since in this case, you can simplify this process as much as possible. Otherwise, you will probably have to violate the integrity of not only the system itself, but also the roof.
What causes a chimney to deteriorate?
- The thermal insulation of a chimney does not always guarantee its long service life and full satisfaction of all your expectations. Quite often, when doing insulation with your own hands, pipes can soon begin to collapse, lose their tightness, and become deformed. There are certain reasons for this, the most common of which you can read below:
- Even basalt insulation for a chimney, if the pipe itself is incorrectly positioned or the installation process is violated, may become unusable. In this case. Increased dampness occurs in the system. Excessive humidity is caused by the settling of warm air vapors on the inner surface of the system, which in turn form condensation, which leads to destruction;
Without knowing how to insulate a chimney, it is important to remember that during the use of a heating unit running on solid fuel, the surface and materials are exposed to various sulfuric, carbonic, and nitric acids, which can also cause destruction. This is especially likely if you use the fireplace or stove irregularly, with a lot of downtime.
A metal chimney system can be installed even in a wooden house
Important: by choosing non-flammable insulation for the chimney, you can make all the processes described above more gentle and reduce the likelihood of these problems occurring to a minimum. If the pipe is left unprotected, you will be able to observe the first negative changes, malfunctions, after the first winter season spent without heating.
Advantages of insulated chimneys
Chimney insulation is an excellent option that can significantly increase the service life and operation of pipes with your own hands. Of course, you will not be able to completely protect the material from the effects of atmospheric factors and acids, but it is quite possible to reduce them to a minimum.
What advantages are achieved through insulation:
- In this case, all the resulting acids that negatively affect the chimney system do not settle on the surface and are almost completely removed to the street along with the smoke masses;
- Temperature differences between hot vapors and cooled walls are minimal;
- Insulated pipes are primarily economical. This way, you can reduce the percentage of heat loss, which will be stored longer and distributed throughout the house. As a result, you simultaneously increase the efficiency of the installation and save fuel;
- A layer of internal insulation makes the system simpler, more reliable, and more stable. Thus, it tolerates bad weather conditions and strong gusts of wind well.
Lack of insulation can lead to premature pipe failure, reduced heating efficiency, and freezing
It’s interesting to know: chimney insulation has a positive effect not only on the condition of this system, but also on the roof itself. It becomes more protected and withstands exposure and sudden changes in high temperatures. At the same time, roof repairs with an insulated chimney are carried out much less frequently.
Insulation materials
Insulation of an asbestos or steel chimney can be done with your own hands using various materials, each of which has its own positive qualities, characteristics, and disadvantages.
Since any solid fuel heating unit heats up quite strongly, it should be remembered that only completely non-combustible materials that can withstand temperatures of at least 300 degrees are selected as insulation.
Without knowing what material you can use to do the insulation yourself, both outside and inside it can be done with foil, aerated concrete, glass wool, or mineral wool. The insulation must be suitable for the pipes you use, which can be made of brick or stainless steel.
Metal chimneys lead to the roof and rise above the highest point
Metal chimneys can be installed and installed indoors
Interesting to know: for modern sandwich systems built with your own hands, you can carry out initial plastering of the surface. The use of stainless steel sleeves is also allowed.
Advice: when choosing a thermal insulation material for subsequent DIY work, you need to ensure that the weight of the pipe matches the weight of the roof. Regardless of what the chimney is made of, stainless steel or brick, choose a lighter material, such as foil or mineral wool.
Among the ready-made variations, you can find cylindrical insulation in the assortment of specialized stores, which is additionally equipped with a protective screen made of foil. This variation is perfect for brick chimneys and systems assembled with your own hands from stainless steel.
How to insulate a metal pipe with your own hands
You can supplement your furnace unit with pipes made from a material such as stainless steel. First of all, before carrying out subsequent manipulations, you need to make sure that the system fully complies with all requirements and safety standards.
Requirements for stainless steel chimneys:
- To create a properly functioning traction mechanism, it is necessary that the total height of the pipes be at least five meters;
- Between a pipe made of brick, stainless steel and the roof, other non-combustible materials, it is necessary to leave a small gap, a free space of at least 30 centimeters;
- Outside, at the very top of the chimney, a spark arrester is installed, which can protect the surface of ondulin, slate, and roofing felt from accidental fire.
When passing through ceilings, this surface is sealed and insulated accordingly
Do-it-yourself insulation of a metal two-layer pipe
Advice: the stove unit must be equipped with a smoke exhaust. In addition, a certain fire-prevention distance must be maintained between the ceiling of the room and the ceiling of the stove installation (for metal stoves it is about one and a half meters).
The last step is to wrap the stainless steel pipes around the outside. For what? In order to maximally strengthen, insulate, and seal the structure. But you can do the winding only after you are completely convinced that the design is working correctly, without interruptions.
Material for winding stainless steel chimney pipes
For internal insulation, you can use mineral wool, foil or any other material. However, several other materials are suitable for winding:
- If the stove unit performs a decorative function or is not used as a regularly used heating device, the metal pipe can be treated exclusively with plaster mortar. This option is also suitable for brick chimney systems;
- You can buy a ready-made solution, which is diluted in the required proportion with water and then mixed well;
- Using a spatula, we distribute the solution over the entire surface of the pipe. For additional reinforcement and retention of a thick layer of plaster, it is necessary to fix a reinforcing frame or fiberglass mesh to the surface.
This chimney system is quite bulky with a relatively small weight
When installing, carrying out the system from the side of the building facade, additional fasteners and supports are installed, with an interval of not about one and a half meters
Advice: in order to carry out high-quality winding with your own hands, it is preferable to use mineral wool on the surface of a pipe located in the attic. Fastening is done with masking tape. This method is only used for completely sealed and closed systems.
Insulating metal pipes of a gas furnace
The simplest, most accessible variation, which you can install yourself if you wish, is sandwich pipes. They are two pipes of different diameters inserted into one another. The space between them is filled with mineral fiber insulation. The pipe with a larger diameter serves as a protective sleeve, while the one with a smaller diameter performs a smoke exhaust function.
The winding in this case is made of stainless steel or galvanized steel.
How to properly form a sandwich structure:
- We make a certain number of holes in the roofing, so that their diameter is 20-30 centimeters larger than the cross-section of the chimney;
- We carry out the winding with a slight overlap. In this case, we use mineral fiber, the thickness of which will be at least 6 centimeters;
- We secure the cotton wool with wire, which is wrapped 2-3 times;
- Next, we put on a pre-prepared casing of larger diameter. If necessary, we perform screeding or fixing with adhesive tape (if the steel is very thin).
The best draft will be for the unit whose chimney rises higher than those located on the roof or near the house
Scheme for insulating a chimney in a private house
At the last stage, the pipe must be fixed with the pipe of the stove unit and passed through the roof ceiling. The space around the riser must be filled with non-combustible materials.
From this video you will learn how and with what to insulate a metal chimney pipe:
The operation of the bathhouse must be absolutely safe for humans. To prevent fires from coming into contact with a hot stove or chimney pipe, walls and ceilings, as well as hot surfaces, should be thoroughly insulated. We will tell you in detail how to insulate a chimney pipe in a sauna in this article.
As sad statistics say, during 2014, up to 70% of fires in private baths occurred due to incorrect thermal insulation of metal pipes. Therefore, to help our readers protect themselves and their guests, we will tell you about the materials, as well as the technology for insulating pipes in a bathhouse.
Variety of insulating materials for baths
The favorite material for bathhouses in Russia is wood. However, it tends to be very flammable. To avoid this, people have long learned to insulate the chimney in the bathhouse, as well as the stove and all surfaces - walls, ceilings. For these purposes, any available means were used - clay, asbestos or any other non-flammable materials with a low degree of thermal conductivity.
Another argument in favor of thermal insulation of the chimney is that in this case the pipe will cool much more slowly and condensation will not accumulate in it.
It is a mistake to think that a good solution regarding how to insulate a pipe in a bathhouse would be to mount sheet iron on the ceiling. The metal can heat up very quickly, which in no way prevents fire, so it is not suitable for thermal insulation.
As an alternative to lining the pipe in the bathhouse, you can use red refractory brick. However, for such a design it is necessary to foresee the size of the room in advance, strengthen the foundation and select a design.
Among the modern materials that solve the question of how to wrap a metal chimney pipe in a bathhouse, the following are offered on the market:
- folgoizol;
- thermal insulation
Let's look at each of them in more detail.
Folgoizol
It is a two-layer material consisting of a heat-insulating component and foil. Thanks to the reflective layer, the room does not cool down so quickly, because up to 90% of the heat is retained inside the bath, so it is a very high-quality insulator.
Folgoizol is highly environmentally friendly, because thick food foil is used as a raw material. This material is not afraid of ultraviolet radiation and strong temperature changes - the operating range is from -65 ºС to +175 ºС. Therefore, it will be a completely worthy choice for wrapping a pipe in a bathhouse.
Note that foil insulation is often installed not only around the chimney, but also on the walls and ceiling of the steam room. It serves for high-quality vapor and waterproofing, and also insulates the bathhouse well.
The sauna, lined with foil insulation, can be compared to a thermos based on its operating principle. It heats up quickly and cools down very slowly.
Teploizol
One of the options for wrapping a pipe in a bathhouse is thermal insulation. To produce thermal insulation, foamed polyethylene is used, hidden between two layers of foil, and the top layer of foil in the material is designed to protect the chimney from overheating.
Teploizol appeared on the building materials market relatively recently. The thickness of such material ranges from 2-10 mm.
Thermal insulation is easy to manipulate - you just need to wrap it around the chimney and secure it with metallized tape.
Sandwich pipe as a chimney
Recently, various manufacturers have begun to produce new safe sandwich pipes for baths and saunas. With such a design, there is no longer any need to worry about how to protect the pipe in the bathhouse (more details: " "). The design of such pipes involves quick and convenient assembly of sections inserted into each other. Moreover, it is optimal to use such pipes with an iron stove.
The sandwich pipe is a multilayer structure, inside of which there is a stainless steel frame, then insulation made of mineral or basalt wool is laid, and a galvanized casing is placed on top. Thanks to this structure, soot does not accumulate inside the chimney, the outer layer of metal does not experience overheating, and the entire structure looks beautiful and laconic.
However, we note that it is advisable to install sandwich pipes in dry saunas. But for traditional Russian baths with high humidity, you should choose slightly different thermal insulation options.
Method of insulating a chimney in a Russian bath
If a heater is installed in the bathhouse, then fire-resistant bricks are used to build the chimney. It is able to remain warm for a long time.
When building a brick chimney, you should not save, but it is advisable to approach this issue very responsibly, because its durability depends on the quality of the work performed.
In this case, the best way to isolate a pipe in a bathhouse from the ceiling, roof and other roof elements is to attach sheet metal to these surfaces.
As an option, you can install a protective screen around the chimney into which expanded clay can be poured. It will serve as additional fire protection for all wooden surfaces of the bathhouse, and will also serve as a heat accumulator.
However, complete safety in a bathhouse cannot be achieved by insulating pipes alone. Similar actions must be performed with the stove, walls and ceiling.
Insulation of the stove in the bathhouse
Currently, bathhouses often use simple metal stoves, which are lined with sheet metal on the sides and back, and installed directly on the foundation. To ensure that heat is retained in the bathhouse for a long time and to make it presentable, the stove can be lined with red refractory bricks.
Currently, asbestos sheets are no longer used for stove insulation, since it releases toxic substances when heated.
It is advisable to use natural felt to insulate the stove. Although this material is quite expensive, it is an excellent insulator. In addition, when a spark hits the felt, it does not flare up, but begins to smolder, so you will immediately notice the problem by the characteristic pungent odor.
When installing the stove on a wooden floor, you should first lay felt in two layers, and then lay the brick in three rows. Sheet metal is mounted on the walls and floor around the stove in pieces 50-70 cm high.
We hope that this article was able to answer the most frequently asked questions among novice builders. Let us remind you that high-quality thermal insulation of the chimney, stove, as well as all surfaces of the bathhouse will not only keep you warm longer, but also protect yourself and your loved ones.
When deciding how to insulate a chimney pipe, one most often chooses among traditional non-combustible thermal insulation materials. There is also a demand for new approaches to arranging chimney structures in the form of sandwich pipes, which can be easily implemented into the chimney system with your own hands.
The gas removal process is accompanied by the accumulation of particles of combustion products on the walls of the smoke channel and the formation of condensate, which negatively affects the performance of heating equipment. Insulation of an asbestos, ceramic or metal exhaust pipe helps to level out problems with a decrease in the efficiency of the device, therefore it is recommended to perform high-quality thermal insulation of the chimney at the construction stage. If necessary, insulate the gas exhaust channel during operation, using a suitable material with a low thermal conductivity coefficient.
What does chimney insulation provide:
- The risk of exposure to factors that cause damage to the surfaces of metal, ceramic or asbestos gas exhaust pipes is reduced. Thus, the presence of high-quality thermal protection helps eliminate problems with condensation. In this case, a significant increase in the potential of the exhaust channel is observed.
- Problems with deteriorating traction are leveled out. With reliable thermal insulation, the level of thermal conductivity of the pipe material is reduced. This explains the decrease in the temperature difference between the combustion product flows and the surface of the smoke exhaust line. As a result, the level of deposits on the walls is significantly reduced and the risk of deterioration in traction is eliminated.
- The energy efficiency of the heat generating device is optimized. An insulated chimney ensures correct consumption of fuel resources, as energy costs for maintaining the required temperature level in the combustion chamber are reduced.
- The strength characteristics of the structure are improved. Using a thermal insulation frame, a kind of reinforcement of the structure is performed, which is especially important when arranging the chimney section above the roof level. Reinforced with a reliable layer of heat-protective materials, the smoke channel is not afraid of significant wind loads, temperature changes and other external factors.
High-quality thermal insulation is important not only when installing thin-walled steel smoke exhaust pipes. Insulation with materials with a low thermal conductivity helps to improve the efficiency of brick chimneys and purlins made of asbestos, metal and ceramics.
Insulation materials for thermal insulation of chimneys
According to the regulations, only non-combustible materials can be used to insulate a chimney to ensure the fire safety of the structure. Among the popular means of thermal insulation of smoke ducts, there are 3 categories - plaster, slag and stone wool.
Plaster
When planning how to insulate a brick or stone chimney on the street, you can use a heat-resistant plaster mortar. To apply the finishing mixture, the surface must be reinforced with a metal mesh.
Broken brick or slag
If a brick duct or iron chimney is to be insulated, a casing is constructed from available materials, and the voids are filled with broken bricks or other non-combustible material.
Stone wool
When deciding how to insulate a metal smoke exhaust pipe with your own hands, they most often give preference to basalt wool. Insulation options in the form of cylinders are of interest: the material is presented with different internal cross-sections. You can also use basalt mats. Thermal protection made of stone wool is wrapped around an iron pipe and secured with clamps or metal wire. The structure is then equipped with a sealed steel casing.
Criterias of choice
The key criteria for choosing a material for insulating a chimney structure are a high level of non-flammability and a low thermal conductivity coefficient of the product. Also, when choosing insulation, take into account the following points:
- the mass of the thermal protection structure must be commensurate with the withstanding potential of the roofing system;
- if insulation with mineral wool is planned, the thermal insulation layer should be protected from the harmful effects of moisture. For this purpose, a sealed steel casing is made;
- To insulate a metal chimney with your own hands, you can opt for ready-made cylindrical insulation with a reflective surface made of foil.
When choosing heat-protective products, it is necessary to take into account the features of insulation of the smoke duct, depending on the base material. Thus, for steel and asbestos chimneys with a height of more than 6 m, a thermal insulation layer 10 cm thick is required. When installing brick smoke exhaust ducts, it is recommended to use materials with a total thickness of up to 8 cm.
Before purchasing insulation products, you should work on the installation diagram and calculate the materials in accordance with the parameters of the structure being installed.
Thermal insulation methods depending on the chimney material
Work on insulating a chimney structure varies depending on the base material, but in each case a preliminary inspection of the object is required for the reliability and fire safety of the system.
Insulation of a brick chimney
When arranging thermal insulation for a chimney in the form of a brick shaft, plastering is mainly used. This reduces heat loss by up to 25%.
Plastering technology includes the following steps:
- Based on a heat-resistant mixture, a very dense mortar is prepared, which is used to seal the seams of the brickwork, filling all the voids.
- Fix the reinforcing mesh and begin applying the first plaster layer with a thickness of 3-4 cm.
- The second layer is performed after the previous one has set, the thickness is 5-7 cm.
- After the plaster coating has dried, apply the finishing layer. To do this, the surface is carefully leveled, rubbed with a trowel, and the resulting cracks are covered.
The final stage is performed using bleaching solutions, which are applied in 2-3 layers for greater decorativeness.
How to insulate a brick chimney with mineral wool?
After inspecting the structure for defects and eliminating them, mineral thermal insulation is attached to the brick surface using wire piercing. In this case, it is necessary to ensure that no voids are formed; special attention is paid to the joints. Next, the finishing coating is made of galvanized steel sheets; the metal casing helps eliminate the risk of reducing the performance properties of the mineral insulation.
Thermal insulation of asbestos pipes
To insulate asbestos-cement smoke ducts, mineral wool is used complete with a metal casing.
Stages of work:
- it is necessary to prepare the calculated amount of fiber insulation and a tubular structure of the required size made of galvanized steel. Most often, a folding casing of several elements is used, the cross-section of which should be 6 cm larger than the diameter of the asbestos chimney pipe;
- the lower part of the casing is fixed to the base of the chimney structure and the gap between the walls of the asbestos-cement pipe and the steel cladding is carefully filled;
- then fix the second casing element and continue to fill the voids with insulation. This way they will work the entire length of the asbestos chimney duct.
The upper boundary of the gap is carefully sealed with cement mortar to ensure the tightness of the thermal insulation.
Nuances of insulating a steel chimney
Thermal protection of a steel chimney structure is carried out in various ways:
- equip a frame from improvised means and fill the gap with non-flammable insulation in the form of mineral wool, household brick, screened slag;
- wrap a metal chimney with mineral wool, install a facing structure made of galvanized steel sheet on top;
- For thermal insulation of an iron chimney, a ready-made heat-protective cylinder is used.
To build a frame for insulating a gas vent from steel, a box is made of lumber and the structure is sheathed with asbestos slabs. Between the perimeter of the metal smoke exhaust duct and the inner surface of the duct, a distance of 10 cm is maintained, depending on the type of insulation chosen.
It is recommended to give preference to lightweight thermal insulation options made from basalt wool, glass wool or slag wool. This allows you to reduce the local load on the roof. If the load-bearing capacity of the roofing system is beyond doubt, broken bricks or screened slag can also be used. The upper end of the box and the joints should be protected from moisture penetration; for this, cement mortar is used.
If insulation in the form of a basalt cylinder is selected, a workpiece of the required diameter is selected taking into account the parameters of the steel gas outlet being installed. The finished cylinder is installed (put on) on the pipe, having previously treated its inner surface and tongue-and-groove connecting elements with a heat-resistant sealant. Next, the sandwich chimney is equipped with an outer metal covering. It is necessary to ensure that there are no gaps or voids between the main chimney and the external one. If a seamless tubular structure is used as the external element, sealant is used to seal vulnerable areas of the end.
Features of insulation of chimneys of various shapes
When installing chimneys of square or rectangular shapes, thermal insulation is performed using a frame. Using the same technology, you can also insulate smoke ducts with a round cross-section. For example, to insulate an asbestos chimney consisting of several pipes, the construction of a frame box is required.
Sequence of work on insulating smoke shafts of square or rectangular configuration:
- maintaining an interval of 10 cm from the perimeter of the object being equipped, assemble a frame from metal profiles or a wooden block. Fastening is carried out using galvanized nails and self-tapping screws 30-50 mm long;
- the space between the sheathing and the walls of the gas outlet shaft is filled with mineral insulation;
- the outer perimeter of the frame is sheathed with asbestos panels 10-12 mm thick.
At the final stage, the joining seams are filled with heat-resistant plaster, as is the upper perimeter of the frame, to ensure the tightness of the structure.
Common mistakes when insulating
Among the main mistakes when thermally insulating a chimney are incorrect calculation of the thickness of the insulation and poor-quality sealing of the thermal protection. During a test fire, you can diagnose the quality of the work performed using a hand-held thermal imager. The level of heat loss is reflected on the equipment screen if thermal energy leaks into the area of walls and joints.
If condensation is observed on the internal surfaces of the chimney after thermal protection work, this indicates that the thickness of the insulation layer is insufficient. Inadequate tightness is fraught with burnout of the chimney. In both cases, you will have to do the work again. To do this, remove the outer metal cladding/casing and carry out thermal insulation in compliance with the technology.
To avoid malfunctions in the operation of the heat-generating device and disruptions in the roofing system, it is important to insulate the chimney in advance.