Insulation of a brick chimney outside

It’s essential to insulate a brick chimney outside of your house to preserve energy efficiency and guard against future damage. In addition to minimizing the chance of moisture seeping into the masonry, which over time may cause structural problems, you can minimize heat loss during the winter months by adequately insulating the chimney.

Even though they are strong and attractive, brick chimneys can lose a lot of heat if they are not properly insulated. Uninsulated chimneys can act as a thermal funnel in the winter, sucking heat out of your house and driving up your heating bills. Enhancing energy efficiency and retaining interior heat can be achieved by insulating the outside of the chimney.

There are numerous efficient ways to insulate the exterior of a brick chimney. One popular method is to use materials like mineral wool, fiberglass, or foam board to apply insulation directly to the chimney surface. Because of their ability to withstand heat, these materials are used in chimney walls to reduce heat transfer.

Ensuring the longevity and effectiveness of the insulation requires proper installation. In order to stop air leaks, the insulation needs to be tightly fastened to the chimney structure, paying close attention to sealing any joints or gaps. Its performance and longevity can also be increased by covering the insulation with a weather-resistant barrier, like a sturdy cladding or customized chimney wrap.

Correct ways to insulate the chimney

When designing a heating system for a private home, insulation for the chimney may become necessary. Preventing condensate loss is essential as it can cause harm to the pipes and interfere with the building’s operation.

Where you need to insulate

In locations where the warm pipe surface comes into contact with ambient air, insulation is necessary. This occurs after the roof is taken off and in the confines of a chilly attic. When doing DIY projects around the house, you should be mindful of ventilation ducts, which also require insulation, in addition to chimneys.

Every time warm air passes through, condensation always occurs. This will occur inside the pipe in the chimney’s case, causing damage as well as rolling moisture down to the heating device and weakening of the thrust. The pipeline must not be allowed to cool in order to avoid this.

Chimney thermal insulation

The choice of material

Accomplishment with fire safety technique requires accurate selection of thermal insulation material, which you must do yourself.

It is strictly forbidden to use combustible and smooth materials for insulation in chimney pipes, which serve as conduits for heated air.

Mineral wool is the only substance that satisfies these specifications. You can use heat-insulators, which are made of mats rolled into rolls or specifically designed forms for pipes, to insulate the pipes (though these are not appropriate for brick chimneys). Safety precautions should be followed when installing mineral wool insulation on your own. The following personal protective equipment should be carried by every worker:

Good thermal-insulating substance

  • mask or respirator;
  • glasses;
  • gloves;
  • Closed clothes.

This is required to prevent the material’s particles from getting on the skin, in the eyes, or in the light. Minvates fibers have the potential to seriously irritate and itchy skin and mucous membranes.

The temperature of the generated gases, the outside temperature, and the pipe’s location are taken into consideration when choosing the insulation’s thickness:

  • for external – within 70-100 mm;
  • for the building located inside – within 30-50 mm.

The following types of mineral wool can be used: slag, glass wool, and basalt. Read the manufacturer’s instructions before using the heat insulator. Apart from this useful substance, a brick fight is also occasionally employed as a low-cost substitute.

Insulation of a brick chimney

To prevent freezing and condensate loss in the pipe, there are two methods to perform maintenance:

First, you will need to take the following steps in order to protect the pipes with your hands:

  1. Fixation of the reinforcing mesh to the surface of the wall. Before that, the design is cleaned of dust and dirt.
  2. Preparation of plaster solution. To do this, mix lime, cement and slag with the addition of water. It is possible to use modern "warm" plaster, which has good thermal insulation characteristics.
  3. Applying the solution to the surface. The thickness of one layer is 20-30 mm. If necessary, the composition is applied to several layers. Each subsequent is laid after the previous. The last layer of plaster solution is aligned and wiped.
  4. After the plaster drying, the surface is checked for the presence of cracks and bumps. If necessary, they are eliminated. The work ends with the color of the pipe with lime or chalk paint to protect the plaster layer from the negative effects of the environment.

Plaster layer application

This is not a productive method.

Shield the pipe from the chilly mineral wool more consistently. If you prefer to handle everything by hand, follow the following plan:

  1. The surface is cleaned of pollution and deposits. Inspection for the presence of irregularities and eliminating them if necessary.
  2. The collection of the frame on which the insulation will be mounted. The crate consists of metal guide profiles, which are fixed with dowels. The step between the guides is selected so that it is convenient to lay the insulation.
  3. The appearance of gaps and cracks should not be allowed. They will lead to thermal losses and the occurrence of cold bridges.
  4. Consolidation of vapor barrier with an overlap 15–20 cm. The joints of the joints are glued with construction tape.
  5. Pipe lining performs a decorative and protective function. When performing work with your own hands in a cold attic, you can use drywall sheets.

Mineral wool for thermal insulation

Warming of stainless steel and asbestos pipes

The components that are shielded by this technology are an extra protective pipe and an internal pipeline that is encased in an insulation casing. Steel that has been galvanized makes up the exterior.

Mineral wool in rolls or specialty pipes for pipes can be used as insulation.

It’s crucial to adhere to the following guidelines when performing work:

  • When warming the chimney made of stainless steel located outside, the heat insulation thickness should be no more than 100 mm;
  • For plots located inside the building, the maximum thickness of thermal insulation is 40 mm.

Transient thermal shielding

It is possible to insulate chimney pipes made of asbestone in a straightforward manner without incurring significant labor costs. This choice works well as a stopgap to shield the chimney from the elements and condensate leaks. He doesn’t last long. This is how the work is completed:

  • prepare mineral wool in rolls;
  • wrap the tube with this material (if necessary in several layers, depends on the required heat -insulation thickness);
  • tighten and fix the material with brackets.

This technique should only be applied in a cold attic. Without a protective layer, the material is susceptible to moisture and the damaging effects of the medium, making it incapable of functioning in external environments.

In order to implement complete insulation, the subsequent set of actions must be completed:

Steel pipe’s thermal insulation

  1. Make a galvanized steel casing. When selecting the width of the sheet for manufacture, take into account the necessary diameter of the inner pipe (so that the insulation of the desired thickness is placed between the two layers of the galvanizing). With a large length of pipes, it is recommended to make an outer pipe from components, the maximum length of which is 150 cm.
  2. The surface of the pipe and place for work is cleaned of dirt, dust, garbage.
  3. Fix the lower part of the galvanized casing. Fill the space between the pipes insulation. Install the next element of steel and repeat the process. It is important to ensure a tight adjustment of the casing elements to each other.
  4. Having reached the top of the chimney, the structure is installed with a small slope. All existing gaps are eliminated using a cement mortar.

The absence of traction and violation of the structure’s design mode won’t concern a competent insulator of the pipeline used to remove combustion products.

The design of the chimney affects the insulation technology. Expert advice will assist you in selecting the best plan and appropriate materials.

"It is essential to insulate a brick chimney from the outside in order to increase energy efficiency and shield your chimney from weather damage. Homeowners can minimize moisture buildup that can cause structural deterioration and prevent heat loss during the winter months by wrapping the chimney in insulating materials like foam boards or specialty wraps. This procedure is a wise investment in long-term home maintenance because it not only helps to maintain a steady interior temperature but also increases the chimney’s lifespan."

Insulation of brick chimneys

In our area, the heating season lasts for six months. During this period, heating appliances operate nearly every day. When natural gas is available in a home, the combustion process continues almost nonstop. Additionally, turning on the furnace and heating the entire house is a necessary practice in homes with stove heating that are used daily (or twice a day on cold days).

Why insulate the chimney?

There are days when starting a fire is really challenging. Condensate, which enters the chimney and exacerbates the flow of gases, is one of the causes. Heat transfer from hot gases resulting from fuel combustion is observed to the environment if the pipe is insulated. A high temperature differential within the enclosing structure’s walls creates the conditions for a "dew point."

The following are formed in the combustion products of various fuel types:

  • water vapor, in fuel there is necessarily hydrogen, which, when burning and forms a water molecule. It is the same white smoke or water vapor visible during the operation of the furnace;
  • carbon dioxide – carbon burning product. When using black carbon coals, there is more carbon, but if brown coals are used, then the fraction of carbon is reduced in them, and the presence of hydrogen increases. When the carbon dioxide and water vapor is combined, weak carbonic acid is formed. The connection is unstable, but has a clearly expressed sour reaction;
  • sulfur gas – a product of sulfur combustion. Sulfur is a by -product present in almost all types of solid or liquid fuel. It also connects to air oxygen, releasing heat. When combined with water steam, rather caustic sulfuric acid is formed. It destroys almost any structural material used in construction;
  • Phosphorus oxide is formed when firewood or fuel briquettes obtained on the basis of plant raw materials. When combined with water steam, orthophosphoric acid is formed. This acid has the ability to accumulate in porous structures, destroying them.

Acid is transformed from a steam-shaped (gaseous) state into a liquid in the presence of condensate. They actively interact with the clay, lime, and other materials that are used to make the chimney when they are liquid. Masonry is consequently destroyed.

It has been observed that the brick pipe’s external insulation aids in transferring the combustion products only in a gaseous form outside the pipe.

Outside the duct, the so-called "dew point" moves from the inner layer. If acidic compounds do develop, they do so outside of the heating system. Occasionally, you can see how condensate snowflakes, or frozen ice grains, emerge from extremely cold frost caused by smoke fumes. An acidic reaction or the presence of the same acids produced when combustion products combine with water steam are indicated by chemical analysis. Condensate snowflakes with a milder acidic reaction already form when natural gas heating systems are in operation. This fuel’s predominant component, hydrogen, controls the makeup of the gases that result from combustion.

You can insulate in different ways

Plaster solution can be applied thickly to pipe masonry. It is known that burned clay, or brick, has a heat transfer coefficient of 0.76 W/(m*° C). In a plaster solution that is complex and contains a light filler, the value is approximately 0.21 W/(m*° C). The simplest insulation is this one. The chimney pipe is plastered after a grid is stuffed on it outside. The thickness of the thermal insulation layer is increased by repeating this process multiple times. Expert experts raise it to 80 or 100 mm. Thermal insulation has a strong relationship with the foundation.

According to statistics, an insulated brick chimney with a plaster layer has a three- to four-fold increased "life."

Chimney insulation can be applied in different ways. The foundation of these is the utilization of materials with extremely low heat transfer coefficients, 0.02–0.04 W/(m*° C). Glass wool, mineral wool, basalt fiber, and other materials are examples of such heaters. However, due to their low mechanical strength, a metal frame must be made in order to use these materials.

How to implement good insulation in a real design?

In this case, a metal sheet serves as the casing. Where heaters are installed, a minimum 50 mm space must be left between the casing and the pipe. After priming, atmospheric paint is applied to the casing. The brick pipe’s insulation system is now shielded from moisture’s outside effects.

Some experts, who are not very skilled, wrap mineral wool around the brick chimney and secure it with a wire so that it is not hermetically sealed. Claiming to have finished their work, they cover the exterior with foil. A layer of porous material becomes wet as a result of atmospheric moisture penetrating it.

The thermal insulation layer’s thermal conductivity is drastically decreased. The pipe is vulnerable to corrosion from both the exterior and internal walls. Moisture moves into the pipe’s body, where it destroys the material even more severely because there is nowhere for it to evaporate.

When building cottages, the practice of swapping out square canals for round ones is used to minimize the labor-intensive bricklaying process. Simply install an asbestos-cement pipe inside to achieve the desired effect. Around it is a heater. Next, create a brickwork surround. Thus, the insulation is consistently concealed behind a layer of brick inside the pipe itself.

A temperature distribution analysis of such a pipe was conducted in 1997 at the Tashkent Polytechnic Institute’s Department of Heat Engineering. The analysis demonstrated how effectively insulation functions in a multi-layer pipe. The temperature increased by just 1-2 °C on its surface. A 50 mm insulation was heated by 20–30 °C in other combinations (without lining with a brick wall), indicating a decrease in the intensity of heat transfer caused by both convective and thermal conductivity. Consequently, you can arrange insulation more effectively by shielding the insulating material from the exterior with a second layer.

Recent years have seen the proposal of an intriguing and promising polystyrene concrete by researchers and developers working in the building materials field. Because of this material’s strength, supporting walls can be built out of it. Its own thermal conductivity is 0.065… 0.085 W/(m*° C), which is extremely low. The indication is sufficient.

Concrete made of polystyrene is not limited to blocks. When it’s liquid, it can be poured into various shapes, used to make bricks, or used to coat the chimney to provide external thermal insulation. The experience with using this modified concrete demonstrates that it has excellent potential for use as both a heat-protective material and the primary structural component.

It is sufficient to cover the pipe with a polystyrene concrete casing in order to provide dependable insulation. Typically, this casing is made of straight and corner bricks adhered with a special glue. Using only a binder, it bears a resemblance to the designer "Lego," ensuring the strength of the finished product. The thermal insulation of the brick chimney is dependable.

Why is the chimney insulation is needed?

The chimney’s insulation is one of the most crucial tasks in getting ready for winter. Properly installed thermal insulation prolongs the service life of the dialing pipes and prevents hypothermia of heated gases. After all, the elements—cold, changing moisture levels, and time—degrade any material used to build a chimney.

The most common materials used to construct a stove chimney in a private home are asbestos pipes, steel, or brick. Both benefits and drawbacks are present. However, it is necessary to complete the chimney’s heat insulation.

Why the chimney insulation

Many owners do not know why the chimney should be insulated. Smoke is produced when a steam or gas boiler operates, warming the furnace discharge walls. The craving shifts when the boiler’s pipe walls warm up. As a result of its decrease, carbon monoxide starts to enter the space and can be poisonous. Furthermore, insulation of the chimney pipe is required to avoid condensate-induced cracking of the discharge walls.

The chimney’s exterior section is colder due to its insulated interior section. This contributes to fire safety.

Necessary tools

Steel chimney.

The chimney is a coaxial structure made up of two stainless steel pipes with varying diameters. A chimney heater is installed in the space created by the pipes being inserted one into the other. These chimneys heat up more quickly than brick. Mounting them with your hands is simpler. If the steel chimney is shielded from direct exposure to moisture, its service life will be extended.

A heater that is three to five centimeters thick is needed for the chimney’s interior section. A material that is roughly 7 to 10 cm thick is used to insulate the exterior of the chimney pipe.

Thermal insulation materials are placed on top of the discharge to insulate the asbestos-cement pipe chimney. Slag or brick is used as insulation for the pipe that runs beneath the roof over the attic overlap.

The first step is to construct a holding heat insulator, which is a galvanized iron cover that is either rectangular or cylindrical. Its diameter should be 10–12 cm greater than the chimney’s exterior diameter. The casing is composed of individual pieces, each of which should not be longer than 150 cm. This will make tamping the insulation easier.

Pieces of the casing should not be joined together if there is more than 10 cm of space between them. Up to the upper edge, asbestos cement insulation is installed around the chimney. It is necessary to mount the upper section slightly sloping.

All of the spaces left between the insulation and the iron casing are filled with cement once the insulation has been installed. Usually, an M-150 brand solution is utilized for this.

It is sufficient to use brackets to secure the mineral wool directly around the chimney pipe in situations where the external metal casing is not suitable. Chimney insulation needs to be installed with a fairly thick layer in areas with cold climates.

There are various ways to insulate brick-built chimneys. The plastering technique is one of these. By using this insulation technique, you can minimize heat loss and increase furnace efficiency.

Use lime, medium-sized slag (which must be pre-rinsed and sifted), and a small amount of cement to prepare the mixture. Multiple layers of thermal insulation are placed on top of a pre-fixed reinforcing mesh. The heat insulator’s inner layer should have a maximum thickness of 40 mm. The next layer of the mixture is applied once the solution has dried. It gets thicker until it reaches 70 mm. Five layers are possible to apply. The first layer’s mixture isn’t particularly thick. The solution gets thicker for each subsequent layer.

The final plaster layer needs to be wiped and leveled. Chalk or lime can be used to whitewash the chimney at the conclusion.

Remember to include the mineral-basalt slabs in your solution when figuring out how to insulate brick chimneys. Installing the heat-insulator slabs on the pipes can be done using:

  • wire fixing brackets;
  • heat -resistant metallized adhesive tape;
  • pins or nails with washers.

The insulation’s surface is decorated by adding ornamental brickwork or asbestos-cement slabs. The facing plates must have a thickness of 40 mm. A specialized facing solution is used to fix them. Masonry with brick faces is plastered.

These kinds of chimney thermal insulation allow you to:

  • reduce heat loss by 50%;
  • increase the efficiency of stove lifting;
  • avoid moisture condensation on pipes;
  • reduce the fire hazard of the heating system;
  • Increase the term of uninterrupted operation of the furnace pipes.

Wooden insulation during a war.

Using wooden shields, heating the chimney’s heat insulation by hand is not difficult. The following techniques are most frequently used to install this kind of insulation.

You could use a slate-lined wooden frame. The chimney’s dimensions dictate the parameters of the wooden frame. Installing prepared shields along the chimney’s contour, slightly inward from its outer edge, is required. Expanded clay, finely divided slag, or sand clog the spaces between the pipe and shields.

The second method of insulating a chimney involves installing protective shields with a maximum 0.1-meter gap along the pipe’s perimeter. The internal connecting seams need to be covered with asbestos sheath or protected with felt. You must place slate or roofing iron sheets on top of the felt. Outside, a cement mortar is applied.

The chimney’s insulation is one of the most crucial tasks in getting ready for winter. Properly installed thermal insulation will not only shield against

The comfort and energy efficiency of your home can be greatly impacted by taking into account a few important factors when it comes to external brick chimney insulation. In addition to preventing heat loss during the winter, insulating the exterior of a brick chimney can enhance the overall insulation of your house. You can lower heating costs by creating a barrier that lessens heat transfer by wrapping the chimney with the proper insulation.

Selecting the appropriate insulation material is essential for efficient thermal functioning. Materials with good insulation qualities and the capacity to tolerate high temperatures, like mineral wool and rigid foam board, are frequently utilized. To keep the material’s efficacy over time, make sure it’s weather-resistant and appropriate for outdoor use.

The secret to maximizing the advantages of exterior chimney insulation is proper installation. To avoid thermal bridging, the insulation around the chimney needs to be applied firmly and uniformly, covering all exposed areas. To guarantee that the insulation is installed accurately and efficiently, it is imperative that you adhere to the manufacturer’s instructions and think about seeking professional advice.

In order to preserve its efficiency and spot any possible problems, it’s also critical to routinely inspect the insulation and chimney structure. The performance of the insulation can be impacted over time by wear and weather, so routine inspections and maintenance can help extend its life and guarantee ongoing energy savings.

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Alexandra Fedorova

Journalist, author of articles on construction and repair. I will help you understand the complex issues related to the choice and installation of the roof.

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