home Calculation

How to lay a brick chimney with your own hands - theory and practice. How to build a brick chimney Drawings of brick chimneys

A chimney for a stove can be built with your own hands if a diagram of its laying is at hand, and the House master has at least minimal skills in working as a mason. The construction of this department requires no less serious approach than that, since the efficiency of heating, the safety of those living in the house, and the overall service life of the entire heating structure will depend on the quality of its masonry.

When working on a chimney, you must remember that its internal surfaces must be as neat and smooth as the external ones, since this factor directly affects the creation of good draft.

Types of brick chimney pipes

Chimney pipes are divided into types depending on their installation location relative to the stove itself. So, they are root, mounted and wall.

The most common design of a brick chimney is the captive one. It is installed directly on top of the heating device and is its continuation. Such chimneys are often installed during the construction of a heating or sauna stove.

The second most popular is the root chimney. This type of pipe is distinguished by the fact that it is installed next to the furnace or is included in its structure and is placed on one of its sides.

Root pipes can be installed for both brick and cast iron stoves. In addition, one root structure is often used for several heating devices. For example, in a two or three-story house, one chimney is passed through all floors and stoves are connected to it. If you plan to use a pipe in this way, then in this case, an accurate calculation of its parameters must be made, otherwise there will be no normal draft, which means that the efficiency of the stoves will decrease and the risk of combustion products entering the premises will increase.

The wall pipe is built into capital internal or external walls. But, in the latter case, the walls of the chimney will have to be very well insulated, since due to the large difference in external and internal temperatures, condensation will actively collect inside the channel, which will significantly worsen the operation of the stove, reducing draft and contributing to the rapid overgrowing of the chimney with soot.

It should be noted that although this structure is identified as a separate type, it can be either root or mounted.

Brick chimney design

The chimney has several sections. To understand its fundamental design, we can take as an example the structure of the mounted pipe, since most often this is what design engineers choose when drawing up furnace layout diagrams.

So, the design of the mounted pipe with its passage through the attic floor and rafter system includes the following sections and elements:

1 – Metal cap or umbrella. It can have various forms, but its function is always to protect the internal space of the chimney from the penetration of precipitation various types, as well as dust and dirt.

2 – The head of the pipe consists of bricks protruding outward, which will protect the neck of the structure from raindrops that will flow down the protective cap. The metal umbrella is also attached to the protruding parts of the head.

3 – Pipe neck.

4 – A cemented or otherwise waterproofed inclined surface of the otter, designed to drain water that gets onto the neck of the pipe.

5 – Otter. This part of the structure has thicker walls than the pipe neck. The otter should be located where the chimney passes through the rafter system and roof. The thick walls of the otter will protect the flammable materials of the sheathing under the roof from overheating.

6 – Roofing material.

7 – Lathing of the rafter system.

8 – Rafters.

9 – Pipe riser. This department is located in attic Houses.

10 – Fluff. This part of the chimney begins under the ceiling inside the house, passes through the attic floor and ends in the attic, slightly above or flush with the floor beams. The fluff, like the otter, has thicker walls than the neck and riser of the pipe. Increased thickness also protects against overheating wooden beams and other flammable materials of the attic or interfloor.

It should be noted that in some cases, instead of fluff, a metal box is installed in its place around the pipe, filled with non-combustible materials, such as sand, vermiculite or expanded clay. The function of this layer, which has a thickness of 100÷150 mm, is also to protect combustible floor materials from overheating.

11 – Floor beams.

12 - Insulation, which is most often made from asbestos, is in any case necessary to create fire safety, since the walls of the chimney will come into contact with the wood of the floor beams and other materials that make up the floor and ceiling.

13 – Smoke damper, located indoors, in the upper part of the pipe, which allows you to regulate the intensity of the exhaust flows of heated air and combustion products.

14 – Pipe neck, which starts at the top of the furnace - the roof.

Calculations of chimney pipe parameters

The principle of operation of the chimney system is the movement of air masses from the combustion chamber to the exit to the street, that is, from the lower point to the upper. This process occurs through the creation of draft, which occurs due to changes in temperature and pressure. It is thanks to all these factors that the chimney system functions normally.

To create optimal aerodynamic processes, the size of the pipe channel must correspond to the power of the furnace, which, in turn, largely depends on the size of the firebox. The surfaces of the internal chimney space must have smooth walls along which air flows will slide freely without turbulence, and due to this no backdraft will be created. That is why quite often an insert made of a round ceramic pipe is built into a square brick chimney, which has an absolutely smooth surface and no internal corners.

Sectional size

In connection with the mentioned factors, it is necessary to very carefully calculate the internal size of the chimney, taking into account its length, since the larger this parameter, the higher the draft in the pipe.

Of great importance for creating normal draft and high-quality functioning of the heating device is the correspondence of the parameters of the chimney passage and power, as well as the size and number of channels provided for by the design and passing inside the stove.

If the parameters of the internal dimensions of the chimney in cross-section exceed the calculated value, this will lead to rapid cooling of the heated air in it and the formation of condensation, and therefore a decrease in draft. In this case, the necessary balance will be disrupted, and the flows cooling in the upper part of the pipe may return down, creating smoke in the room.

The size of the chimney opening is calculated as follows:

The size of the chimney of a fireplace with an open firebox approximately corresponds to the proportions of 1:10 (chimney cross-section (f) / firebox window area (F)). This formula generally applies to both square or rectangular and cylindrical pipe types, but not directly, but taking into account the cross-sectional shape of the channel and the overall height of the chimney.
The size of the chimney of a stove with a closed combustion chamber has a proportion of 1:1.5. In the case when the heat transfer of a heating structure is less than 300 kcal/hour, the cross-section usually has a size of 130×130 mm or half a brick (not less). When making calculations, it must be taken into account that the cross-sectional size of the chimney should not be smaller than the inlet opening of the ash-blower.

When calculating a fireplace chimney, you can use the following table.

Pipe height N, m		5	6	7	8	9	10	11
		f/f ratio in %
Pipe section	Round	11.2	10.5	10	9.5	9.1	8.7	8.9
	Square	12.4	11.6	11	10.5	10.1	9.7	9.4
	Rectangular	13.2	12.3	11.7	11.2	10.6	10.2	9.8

Pay attention to the direct dependence of the chimney cross-section not only on the parameters of the firebox, but also on the height of the pipe. Probably, sometimes when making calculations it will be more expedient to start from this parameter. For example, a pipe 11 meters high on a one-story country house would look completely ridiculous.

The same dependence, but more accurately presented in graph form.

Let's say you need to calculate the cross-section of a chimney pipe for a fireplace with a firebox, the window dimensions of which are 500×700 mm, that is, the total area – 0.35 m². It is assumed that a pipe with a total height of 7 meters.

Let's look at the graphical diagram:

- for a round chimney cross-section, the optimal ratio is f/f = 9.9%;

- for square - 11,1% ;

- for rectangular - 11,7% .

It is easy to calculate the optimal cross-sectional area of the chimney channel:

- circle: 0.35×0.099 = 0.0346 m²;

- square: 0.35 × 0.11 = 0.0385 m²;

- rectangle: 0.35 × 0.117 = 0.041 m².

Now, using the simplest geometric formulas, it is easy to reduce the areas to linear dimensions:

- diameter round pipe: d = 2×√S/π = 2×√0.0346/3.14 ≈ 0.209 m = 210 mm.

- side of a square pipe: a = √S = √0.0385 ≈ 0.196 m = 196 mm.

- a rectangle can have various options- For example 0.130 × 0.315 m or 130 × 315 mm.

The calculation will be much simpler if you use the calculator below, which already contains all the mentioned dependencies.

In new private houses equipped with heating boilers, they are installed to remove flue gases. traditional brick chimneys, and also increasingly used chimney systems made of steel or ceramics.

Which chimney should you choose? How to properly make a chimney for a boiler in a private house? Where can I buy quality chimney pipes of steel?

For a solid fuel boiler - a brick chimney

A brick chimney is usually costs less, than modern chimney systems. Traditional chimney pipe made of ceramic bricks easily withstands high flue gas temperatures. The pipe can even withstand ignition of soot accumulations in the chimney.

A brick chimney for a boiler in a private house is a rather heavy structure. The chimney is located on the foundation or a solid reinforced concrete floor. The construction of such a chimney requires certain skills; it is better to entrust the laying of a sealed and durable chimney to a qualified stove mason.

Channels and chimneys and ventilation are often placed in a brick chimney

Masonry chimney made from high-quality solid ceramic bricks of a grade not lower than M125 using ordinary masonry mortar. The upper section of the pipe, above the roof, can be laid out of facing or clinker bricks. The thickness of the chimney walls must be at least 120 mm(half a brick).

Brick chimney laying. Ventilation ducts are usually placed next to the chimney in one vertical block. Templates make it easier to lay even channels with smooth walls.

The size of the chimney and ventilation channels is chosen as a multiple of the brick size, taking into account the thickness vertical seams. For example, the channel cross-section can be 140x140 mm(1/2x1/2 brick) or 140x200 mm(1/2x3/4 bricks), or 140x270 mm(1/2 x 1 brick). In practice, a smoke channel is often made measuring 20 x 20 cm(3/4x3/4 bricks). If necessary, it is easy to select and insert a round steel or ceramic liner of the appropriate diameter into such a channel.

The flue gases in the chimney duct should not be very cool. Therefore, they try to build the chimney into the masonry interior wall at home or attached to a wall. Sections of the chimney that pass through an unheated room (attic) or outside the house insulated with mineral wool.

Brick the chimney serves reliably and for a long time only at high flue gas temperatures, which prevents condensation from forming in the pipe. As a rule, this condition is met when the chimney is operated with a conventional one.

When working with modern gas or liquid fuel boilers, as well as with solid fuel pyrolysis boilers, pellet and others, operating for a long time in a slow burning mode of low intensity, the brick chimney is destroyed quite quickly.

Modern boilers are designed in such a way that the exhaust gases have a fairly low temperature. As a result, condensation of water vapor contained in the flue gases occurs in the chimney. The pipe walls are constantly moistened. In addition, when combining with other combustion products, water forms aggressive chemical compounds on the inner surface of the pipe.

In particular, the exhaust gases of boilers contain sulfur, which, interacting with water, forms sulfuric acid in the chimney, which corrodes its walls. External signs of destruction are dark wet spots on the outer surface of the brick pipe.

The operating mode of a solid fuel pyrolysis boiler also contributes to the formation of aggressive condensate in the chimney, which quickly destroys the brick chimney.

Rough chimney walls contribute to the accumulation of solid soot particles on them. The roughness of the walls and the rectangular shape of the chimney duct make it difficult to clean the chimney from deposits.

For connecting gas and other boilers with low flue gas temperatures to a brick chimney, in a brick channel it is necessary to place an insert - a steel or ceramic chimney pipe.

A chimney made of ceramic pipes is a universal solution for a boiler in a private house

Chimneys made of special ceramic chimney pipes can be used for all types of boilers. The material is resistant to high temperatures and to any aggressive chemical compounds that may form in the chimney during combustion different types fuel. This type of chimney is the most durable.

Ceramic chimney pipes are distinguished by the permissible maximum temperature of the exhaust gases.

A brick chimney, which is famous for its good draft and aesthetic appearance, cannot be replaced metal structure. It retains functionality much longer than the pipe. To create a chimney from bricks, you need to clearly understand what this structure is and learn the special rules regarding the features of the masonry.

Advantages of a brick chimney

A chimney made of bricks is most often mounted on a stove, taking into account its advantages such as:

the ability of the material to resist fire;
duration of operation;
ease of brick laying;
no need for specialized maintenance;
easy repair.

The brick channel can withstand high temperatures, but clogs relatively often

A brick chimney can also be characterized on the negative side: it is rough inside and therefore quickly becomes contaminated with soot, the accumulation of which negatively affects the draft force. The disadvantages of a brick chimney also include its heavy weight, which often requires placing the stove on a separate base.

Construction of a brick chimney

You must undertake the construction of a chimney from bricks, being thoroughly prepared for this process.

Chimney laying requires special skills and care

Brick selection

In most situations, the building raw material for constructing a chimney is ordinary red brick. But since there is an opinion that simple material will not withstand high temperatures, some lay out the chimney from refractory bricks, the price of which is much higher.

Builders claim that the use of refractory bricks is justified in cases where it is necessary to build an overmount chimney. It will be exposed to gases with the highest temperature.

The myth that ordinary red brick is not suitable for building a kiln can be debunked. Ordinary bricks are not at risk even at temperatures above 800˚C. And it doesn't get that hot inside the chimney.

Red brick is actively used for the construction of chimneys, as it is resistant to high temperatures.

Simple bricks will not become a reason for frustration if you take their choice seriously. It is worth taking only material with smooth side walls. Bricks with an uneven surface will make inner space the chimney will become even rougher, which will lead to significant contamination of the pipe with combustion products.

Irregularities that appear on bricks during the process of laying and creating joints must be eliminated with a sponge moistened with water.

Sand-lime brick is definitely not suitable for the construction of a chimney. This construction raw material, when heated, releases toxins into the environment, which is why it can be used exclusively for finishing a house with outside.

Sand-lime brick is never used for the construction of chimneys, because it emits harmful substances when heated

When purchasing bricks, it is important to examine the edges on several pieces. They should be completely even. A good brick is one that is distinguished by an ideal parallelepiped shape, sufficient strength and uniform firing.

It is better to lay the chimney from bricks measuring 25x12x6.5 cm.

Brick for chimney over roof

It is strongly recommended to cover the chimney in the area where it exits the roof with facing bricks. True, there are opponents of this rule, who believe that the material used for cladding will collapse almost immediately, which cannot happen with other construction raw materials - clinker bricks.

The part of the chimney above the roof can be created from rough bricks and then covered with clinker material. But there is another option: to immediately assemble the “top” of the pipe from clinker construction raw materials - about 50 bricks.

To give a brick chimney beautiful view, it is lined with facing bricks

Calculation of brick pipe parameters

It is impossible to build a pipe without deciding on the cross-sectional size inside the structure. This parameter is very important because it affects the stove’s ability to get rid of fuel combustion products. The width of the smoke channel always depends on the power of the furnace equipment.

To find out what the internal cross-section of the pipe should be without resorting to complex calculations, you can use one of three standard sizes:

“four”, formed by a line of four bricks and creating a pipe with a cross-section of 12.5x12.5 cm, - perfect option for the smoke duct of a low-power stove;
“five”, formed by a row of five bricks, resulting in a rectangular chimney with a cross-section of 25x12.5 cm, is a version of the pipe for heating and cooking stoves and fireplaces;
The “six”, created in a row of six bricks and allowing the construction of a square smoke channel with a cross-section of 25x25 cm, is a variation of the chimney suitable for fireplaces and Russian stoves, in which it is necessary to organize minimal resistance to the movement of heated combustion products.

Calculation of the chimney cross-section can be simplified if you are guided by standard sizes, which differ in the number of bricks in one row

Another significant parameter for the smoke channel is height. When calculating the length of the pipe, take into account where the pipe exits onto the roof (in relation to the ridge).

A chimney, one and a half meters or less away from the ridge, should rise 50 cm above the roofing material. When the interval between the highest point of the roof and the chimney is 2 or even 3 meters, the height of the smoke duct above the roof is made equal to this distance.

The height of the pipe depends on the distance at which the smoke exhaust duct is removed from the roof ridge

Mortar for smoke duct made of bricks

The mortar used to glue the chimney bricks together is a composition of water, sand and clay. Thanks to these components, the mixture becomes similar to brick in terms of linear expansion. This means that the solution will protect the masonry from the appearance of defects.

The clay used as one of the components of the solution must be clean. There are no other requirements for it, so it’s okay if the taken natural material will be fatty or lean.

The clay mined to prepare the solution should not contain earth or other impurities

Sometimes the clay for preparing the solution does not need to be mixed with sand. We are talking about a situation where the found clay is already saturated with sand in a ratio of 1:3 or 1:4.

If the clay portion is too large, the solution will become covered with cracks when it hardens. And an insufficient amount of this component in the special mixture leads to its crumbling in a dry state.

In masonry mortar, it is important to maintain the correct proportions of components, otherwise it will not be able to perform its functions

You can find out whether the content of components in the solution is optimal simple method: knead the mixture with your fingers. If there are no deviations from the requirements, then the mixture will feel neither slippery nor rough, like a piece of sandpaper.

Sand has different requirements. It’s good if its grains have a large diameter - 1 mm. Raw materials of this size feel rough to the touch. Pulverized sand mined in the floodplain of a stream or river should never be used.

To prepare the solution, you need to take coarse sand, which can form good connection with clay

Preparation of the composition

The solution for creating a chimney from bricks is prepared as follows:

For fear of making a mistake with the quantity of mortar components, you can purchase a ready-made masonry mixture of sand and clay in dry form. The main thing is that the purchased composition is fireproof, otherwise it will not be suitable for laying bricks.

Making a brick smoke channel

Most stoves are suitable for a pipe with a cross-section of 25x12 cm. A smoke channel with these dimensions is created from bricks, which must be specially divided into 2 parts. The bricks are sold in this form. But if you wish, you can cut them yourself using a grinder with a mounted diamond blade.

Brick can be cut not only with a grinder, but also with a saw with a special blade

When laying bricks, the mortar must be applied in a layer no more than 1 cm thick. A thicker layer may crack as it expands due to heat.

It makes no sense to build a relatively complex brick chimney for metal furnace. For such equipment, it is better to find an ordinary iron pipe.

To assemble the correct brick pipe, you will need to complete the masonry according to all the requirements, including the creation of fluff, otter and other parts of the structure

To assemble a smoke channel from bricks, certain tasks are performed:

They are armed with tools, that is, a rubber hammer, a grinder, a spatula, a building level and a tape measure. Measure the distance from the stove to the damper and flue flap.
Starting from the stove, the first lines of bricks are laid out. For each laid out row using building level control the evenness of all four planes. Having created the next 3 lines of bricks, remove the excess sand and clay composition with a damp cloth.
There, a gate will be placed and the frame is secured. Due to its installation, the upper plane of the bricks should not bend. Therefore, you need to make a hole in them the same size as the gate frame.

The gate is mounted so as not to disturb the horizontal level of the masonry plane
The bricks are placed in rows until they reach the place where the fluff is installed. At this moment, count the number of lines from which the expansion of the pipe will be formed at the intersection with attic floor. It is taken into account that one row of bricks increases the perimeter of the smoke channel by 1/4 of the width of the brick.
The fluff is built so that it adjoins the ceiling beams without gaps. In the case of a significant distance between the chimney and the lower surface of the building's floor, special structures are created in the form of frames that help strengthen the fluff. The fact is that a leaky connection between the bricks and the ceiling will lead to loosening of the pipe and leaks in the attic and in rafter system. By the way, the fluff can be not only square, but also rectangular.

The fluff is assembled so that in the middle there are rows of more bricks
Step by step, they move from fluffing to masonry according to the dimensions of the chimney. Rows of bricks are placed until the chimney reaches the roof.
They begin to build an otter on the lower tier of the roof. Here you will have to act extremely carefully, since the expansion of the channel must be carried out step by step, taking into account the degree of inclination of the roof. To facilitate this work, builders recommend placing pieces of sheet metal into the otter during the laying process and fixing them on the rafter legs.

The otter is assembled with a gradual expansion of the chimney channel, taking into account the angle of inclination of the roof
The end edges of the bricks are shortened to reduce the gap between roofing materials and an otter. If you don’t want to cut with a grinder, then metal sheets are installed at the junction of the lower zone of the otter and the roof. With their help it will be possible to avoid leakage into load-bearing structure raindrops from the roof.
Create a decorative part of the smoke channel - the head. To do this, the outer perimeter of the chimney is expanded by a quarter of a brick. The head is formed literally from one row, after which they begin laying out the finishing line of bricks. A metal mesh is installed in the last chain of material - a barrier for birds.

The head of the brick pipe is made with a quarter-brick extension
The top of the chimney is covered with a protective cap using dowels. After two days, during which the mortar between the bricks hardens, the oven is heated for testing purposes. If you detect weak traction, there is no need to panic: the situation will improve after several times of operation. heating equipment. Seams brickwork carefully rubbed down so that the chimney looks aesthetically pleasing.

The protective cap is attached to the head and protects the pipe from precipitation

If you doubt your ability to lay a chimney out of bricks, you can resort to test assembly of the smoke channel. This involves doing the work on the ground without using mortar.

Photo gallery: brick chimneys

The four-brick masonry scheme is used in chimneys for small stoves. On top of the chimney is closed with a special cap - a weather vane. It protects against precipitation getting inside the pipe and can serve decorative element Such large chimneys are built mainly for powerful gas boilers. Some chimneys are covered on top with a protective cap with a ventilation outlet. Most often this is required for gas boilers

Video: example of building a brick chimney

Lining a brick pipe

Lining is a method of restoring the tightness of a chimney by inserting a stainless steel pipe inside it. The need for such an operation arises for certain reasons.

The meaning of the chimney liner

In any case, you will have to deal with deterioration in the operation of the chimney, because the internal walls of the channel become contaminated with soot over time. It is formed quickly and in large quantities if the temperature inside the chimney constantly changes and the combustion products contain chemicals.

It is most common to become clogged with fuel combustion products. brick structures. This is due to the roughness of the internal surface of the brick chimney.

A pipe clogged with soot does not remove smoke well

A smoke channel clogged with soot stops functioning normally, causing backdraft to occur - a phenomenon due to which gases go not up, but down - straight into the house. To normalize draft, they resort to lining the chimney, which allows you to transform the uneven walls inside the chimney into a perfectly smooth surface. In addition, after sealing the channel becomes more airtight, easy to clean and retains heat better.

Most correct option sleeves are a pipe with an oval or round cross-section. A product of a different shape will allow soot to accumulate in the corners.

The liner extends the service life of a brick chimney, as it protects it from soot

Instructions for lining the chimney

Lining a smoke brick channel involves performing the following actions:

Video: chimney lining

Brick pipe repair

To put the pipe in order, you can go in two ways: restore the masonry or perform lining - process the channel inside by special means.

Reconstruction of masonry

In case of minor damage to the chimney masonry, they act quite predictably - instead of destroyed bricks, whole ones are installed. To do this, the crumbled elements are carefully cleaned of the solution and removed. The empty cell is scraped out, after which a new element is placed in place of the taken brick, using a fresh mixture of clay and sand.

In case of minor damage to the masonry, it is restored by replacing individual bricks with new ones

Sometimes a situation arises when cracks appear in the pipe, through which moisture seeps in during heavy rains. In these cases, the outer surface of the pipe above the roof is primed and then plastered.

When the bricks in the masonry are damaged by more than 20%, o partial renovation a chimney is out of the question. The smoke channel with severely damaged elements is completely dismantled to create a new masonry.

Video: one way to repair a brick chimney

Brickwork

Lining is an excellent way out of the situation if the problem is the loss of smoothness and strength by the chimney walls. To complete this task you need a mixture of Masan or Mordax. These compositions simplify the restoration of the chimney’s functionality and do not reduce its cross-section at all.

It will take only a few hours to complete the lining. The operation consists of the following steps:

You may need several different brushes during the lining process. This is explained by the fact that the cross-section of the chimney in certain areas may not be the same. In general, the size of the brush should correspond to the parameters of the smoke channel.

If you comply with the requirements for the masonry process in a house or bathhouse, you can create a safe and durable chimney. A self-made structure can look no worse than the structures of real masters. If you have learned how to build chimneys with your own hands, then you can also make repairs of any complexity without outside help.

The traditional brick chimney for a gas boiler is quite in demand, despite many existing shortcomings and low thermal characteristics. Despite the apparent simplicity of the design, during the construction of a brick channel, it is extremely important to adhere to the existing standards set out in SNiP. Operational safety and operational efficiency depend on compliance with the requirements. gas equipment.

Is a brick chimney allowed or not with a gas boiler?

Existing standards allow the use of brick chimneys for gas boilers. At the same time, the conditions that the smoke exhaust system must meet are separately specified. If violations are detected, the gas service inspector may refuse to put the heating equipment into operation.

The laying of the channel must be carried out by a qualified mason. It is better to avoid installing a chimney for a brick gas boiler with your own hands, without special construction skills. As practice shows, only an experienced stove maker can take into account all the nuances associated with the calculation and subsequent installation of the structure.

Chimney requirements for a brick gas boiler

The main purpose of the chimney is to safely remove combustion products from the boiler. The essence of all requirements is to prevent possible fire, as well as carbon monoxide poisoning during the operation of heating devices. In particular, SNiP and PB indicate:

From time to time, new requirements for a brick chimney for a gas boiler appear. Even before construction begins, find out about existing standards at the Gas Service. Up-to-date information will avoid unnecessary costs and facilitate the commissioning of the structure.

Mono-brick chimneys for gas boilers

There are several options for brick chimneys, among which the mono-design has the worst thermal performance. Under constant exposure to an aggressive environment, the brick is destroyed, the seams crack and lose their tightness. For this reason, after 5-6 years of operation it will be necessary to repair the pipe and replace damaged areas.

During construction, the following conditions are observed:

The disadvantage of a brick smoke exhaust system is its short service life and high requirements for the quality of the masonry. It is difficult to lay out a chimney correctly yourself, so it is better to use the services of a qualified mason.

Combined brick smoke removal systems for gas boilers

Combined systems have better thermal performance than a conventional brick chimney. The main feature of the design is the presence of a core made of steel, ceramics or asbestos cement. Thanks to the combined installation scheme, the disadvantages inherent in brick channels are almost completely eliminated.

When choosing combined systems, you need to pay attention to technical specifications the cores ultimately determine the performance characteristics of the chimney.

Chimneys made of brick and stainless steel

Existing schemes for the construction and restoration of existing chimneys provide for the possibility of using three main modifications, differing in the material of the internal contour. The consumer is offered one of three options:

Before commissioning, old brick chimneys must be lined for use with gas boiler equipment.

Combination of brick and ceramic pipes

This design is one of the best in its characteristics. Ceramics are resistant to acids and can withstand heating up to 1000°C. A ceramic pipe has good traction, quickly warms up and reaches operating mode.

A free-standing brick chimney with an internal ceramic pipe for connecting a gas boiler is used as an alternative.

Problems with a brick chimney with a ceramic core are extremely rare. The design is distinguished by a long service life and resistance of the ceramic walls of the pipe to burnout. Given that correct installation, the chimney will last at least 50 years.

Chimney made of asbestos-cement pipe lined with brick

A chimney pipe made of asbestos pipes, lined with bricks, cannot compete in its characteristics with stainless steel and ceramics. Asbestos-cement systems have gained popularity due to their low cost and availability of the material. At the same time, pipes have several significant disadvantages:

Excessive production of condensate– an asbestos-cement pipe, even inside a brick, cools quickly, which leads to large volumes of condensation. As a result, the chimney often becomes damp and the structure collapses.
Low aerodynamic characteristics– asbestos pipe cannot be used for condensing boilers and gas equipment with a closed combustion chamber.

In terms of its thermal and aerodynamic properties, as well as the ratio of cost and durability, the leading position is occupied by a brick chimney shaft with a stainless pipe inside.

How to make a chimney pipe for a gas boiler from brick

Failure to comply with existing SNiP and GOST increases the danger of a brick chimney when gas heating. Particular attention should be paid to the choice of building material, masonry mortar mixture, and thermal insulation.

It is important to prevent the accelerated formation of condensation and provide for the possibility of regular maintenance of the smoke exhaust system.

What kind of brick is used to make a chimney for a gas boiler?

To use a chimney from gas appliances, ceramic bricks made from baked clay are used. The material retains heat well and can withstand temperature changes. Making a chimney out of sand-lime brick is strictly prohibited.

Any ceramic brick is not suitable for a smoke exhaust system, but only a certain brand. Moreover, for the manufacture of the outer and inner parts, material with different markings is used.

Fire resistance - the material is assigned class “A” or “B”. The first is intended for heating up to 1400°C, the second 1350°C.
Strength - for masonry you need a brick of grade M 250 or M 200. High density leads to an increase in heating time, therefore, use construction material those marked M300 and higher are not recommended.
Frost resistance– the chimney is made of solid ceramic bricks with a resistance factor of F300.

The wall thickness of the brick pipe should be 15 cm (half a brick). When laying, the geometry and right angles of the structure are strictly observed.

The chimney can be made from facing bricks, but the material, which can withstand frost, does not tolerate heating/cooling well. After several heating seasons, the surface begins to crack and crumble. When condensation occurs, the facing material loses its strength.

It is correct to make a brick chimney for a gas boiler in a private house, from solid brick, class “A” or “B”, with strength M 250 and frost resistance F300.

What masonry mixture is used during construction

The composition of the mixture for laying a brick chimney pipe is selected depending on which part of the structure is being built. As practice shows, it is optimal to use ready-made fireproof and heat-resistant masonry mixtures. The resulting solution is acid-resistant and able to withstand negative atmospheric conditions.

If there is no financial opportunity to purchase a ready-made adhesive composition, the mixture is made independently.

Clay mortar– is heat-resistant, used for the construction of structures located in the house. Clay gets wet when exposed to water, so the mixture is not suitable for the outer parts of the chimney.
Cement composition- use cement mortar necessary for parts of the chimney located outside the building. To increase strength and give the solution acid-resistant characteristics, special additives are added to the finished mixture. The same solution is used in the manufacture of the chimney foundation.

A brick chimney is laid out on clay or cement-sand mortar, depending on which part of the structure is being built. Ready-made mixtures are used for the entire smoke exhaust system, regardless of location in relation to gas equipment and the building.

The finished composition of the solutions includes all the necessary additives and plasticizers, which allows you to make a perfectly even seam without leaving voids. The only drawback is the high cost of masonry.

How to insulate a brick chimney

The need to insulate a brick pipe is associated, first of all, with the need to reduce the amount of condensate produced. The walls are heated above the dew point faster, which leads to a decrease in the volume of moisture that falls.

The technology for insulating an external brick chimney is as follows:

First you need to repair the brick pipe. Damaged areas are replaced. Sagging from the masonry mortar is removed, the pipe is primed.
To level the pipe and remove cracks and chips that have appeared, you will need to plaster the brick surface. Work is carried out on lighthouses. The solution is allowed to dry. It is prohibited to heat the chimney during this period.
Thermal insulation of the brick pipe is carried out - the thickness of the insulation is 5-10 cm. external cladding, is attached to a special adhesive composition, after which the plates are fixed using anchors. A reinforcing mesh is pulled over the top, embedding it in a layer of glue.
Finishing is in progress.

The material used for insulating brick gas chimneys can be any basalt thermal insulation. Stone wool does not ignite even when directly exposed to open fire.

To insulate a brick pipe in an unheated attic, use mineral wool. The material costs approximately half as much, and in the absence of precipitation, it performs well as a thermal insulator.

Chimney installation above the roof

Most often, the rules related to the passage of roofing, installation and cladding of the roofing part are violated. Rules for the passage of a brick chimney through wooden floor when heating with a gas boiler, the following:

When passing through slabs or roofing, observe fire breaks. SNiP 01/41/2003 states that from an uninsulated chimney to combustible structures there must be at least 38 cm. For insulated pipes, the gaps are reduced to 5 cm. The space is filled with basalt insulation.
For penetration, a special box is made, installed under the roofing.
The chimney head is insulated with basalt slabs and covered with ceramic tiles or covered with facade plaster.
The height of the pipe is calculated depending on the distance from the ridge. Exists general recommendation so that the brickwork in a private house is higher than the top level of the roof. In some cases, in accordance with this instruction, it will be necessary to rebuild the existing brick chimney to install a modern gas boiler.
The pipe head is covered with a deflector to increase traction force.

Connecting a gas boiler to an existing brick chimney is carried out only if the pipe is of sufficient height and after mandatory lining of the system.

How to prevent condensation and methods for removing moisture

The main factors for the formation of condensation are the following reasons:

Condensate moisture is removed using a special condensate drain that hermetically seals the chimney duct.

Repair of a brick chimney pipe from a gas boiler

Reconstruction of an old chimney may be required in several cases:

A defect discovered during regular inspection of the masonry.
Re-equipment of the smoke exhaust system, allowing the use of conventional brick stove chimneys for modern gas boilers.

Before repair work determine and eliminate the cause that led to the destruction of the brickwork.

Why does the brick on a gas chimney collapse?

The frequency of checking brick chimneys is at least once a year, before the onset of the heating season. Inspection shows the presence or absence of mortar falling out of the seams, brick cracking and other violations. The causes of destruction are:

Is it necessary to line a brick chimney and with what?

Chimney lining is required in the following cases:

To avoid destruction of the structure of the brick smoke exhaust system in the future (average service life is 6 years), lining is carried out. A stainless pipe or corrugation is installed in the chimney.

Additional sealing of chimneys in brick walls for individual gas boilers is required only if ducts intended for ventilation are used.

How to clean a brick pipe with gas heating

You can clean the pipes yourself, which, as practice shows, often leads to the destruction of the brickwork. Without certain qualifications, it is not recommended to clean chimneys, since during the work the internal walls of the channel are destroyed.

Alternatively, you can call a specialist to clean it. The work will cost on average from 600 to 3000 rubles. The time taken is 3-6 hours, depending on the degree of contamination.

Advantages and disadvantages of connecting a gas boiler to a brick chimney

Brick chimney ducts have certain pros and cons. The advantages include:

Low cost with the possibility of using an existing pipe.
Possibility of connecting a gas boiler with an open combustion chamber to a brick chimney.
Availability of construction and finishing materials.

The disadvantages of the design are:

Short service life.
High requirements for the quality of masonry and the qualifications of the worker carrying out construction work.
The need for insulation.
There are many restrictions - making a gas chimney in an external brick wall, using an old duct without liner, connecting the system to condensing boilers and equipment with a closed combustion chamber is prohibited.

Technical characteristics, in particular draft indicators, aerodynamic properties, short service life, call into question the feasibility of installing a gas boiler with a brick smoke removal system. To connect, select or.

There is not a single stove without a chimney. Removal of carbon monoxide and smoke from the firebox - necessary condition proper operation of the stove. What should the pipe be made of and how to arrange it so that it lasts for a long time and does not create additional problems? An experienced stove maker will answer without hesitation - from the same material as the stove itself. This is due to the fact that various materials the coefficient of thermal expansion is different. And if brick and metal are heated at the same time during the fire, then a gap will form at the point of their connection over time. Smoke begins to leak through the gap, this disrupts the smooth operation of the stove, and also poses a serious threat to the life and health of household members. Therefore, if you want to build a chimney for a brick stove, you must also do it from brick.

What is a brick chimney and where is it used?

Chimneys are used to remove gaseous combustion products in stoves, fireplaces and heating boilers. Smoke, carbon monoxide and soot under the influence of draft are carried out of the furnace into the pipe and discharged outside. As they move, they cool down, giving off heat to the walls of the chimney.

To remove combustion products from a brick stove, you need to build a chimney from the same material, i.e. brick

Unlike metal pipes, brick has:

But a brick chimney also has a rather significant disadvantage. IN country houses And country cottages It is not possible to fold cylindrical pipes, which are ideal for the passage of hot gases. The internal cross-section of a square or rectangular shape creates obstacles to the flow of smoke. As a result, a layer of soot quickly forms on the inner walls, which reduces traction. Accordingly, they have to be cleaned more often than metal ones.

Chimney pipe design and operating principle

The classic chimney design is a vertical tower, inside of which there is a through hole that connects the furnace firebox with the open space outside the house. According to the laws of physics, air pressure decreases with distance from the earth's surface. As a result, a draft arises inside the pipe - the desire of the air mass to move from bottom to top. If the air access from below is blocked, the draft disappears. Therefore, a smoke damper or view must be installed in the chimney, with the help of which it is possible to regulate the draft.

Using the damper, you can regulate the size of the smoke channel, and therefore the draft

Since the pipe is operated in residential buildings, it should not pose a fire hazard, therefore the masonry is carried out taking into account maximum protection from possible fire. Among stove makers, a certain terminology has been established that reflects the structure and functional purpose individual pipe elements.

In some cases, a combined pipe design is practiced. The brickwork ends in the attic and then a metal or asbestos pipe is mounted to it, leading to the roof. In this case, there is no need for an otter, neck and head, which significantly saves time and money. It should not be forgotten that the cross-sectional area metal pipe should not differ from the brick cross-section in a smaller direction. The combination of a stainless steel pipe embedded in an asbestos pipe has proven itself well.

In the upper part of the chimney, where the temperature of the flue gases is not so high, you can make a transition from a brick pipe to a metal one

In both cases, the top hole must be closed with an umbrella (or deflector), which will prevent rain and snow from directly entering the pipe.

Calculation of main pipe parameters

All calculations for the chimney must be performed at the design stage of the stove. The project must be carried out by a qualified engineer or craftsman who is well versed in all the nuances of the furnace business. It is impossible to plan the dimensions of the pipe in isolation from the dimensions of the firebox and heat exchanger. Everything is interconnected and must correspond to one goal - the coordinated operation of the furnace equipment.

If, when building a fireplace, the “body” of the stove is missing, and the firebox is directly connected to the chimney, then the Russian stove additionally has heating ducts in the walls, and it is impossible not to make allowances for this. The presence of passages changes the draft and lengthens the path of the flue gases several times. Accordingly, the chimney must create greater vacuum so that the movement of gases is accelerated and soot does not settle inside the passage. A separate topic could be the calculation of chimney parameters in sauna stove. It is important here that the draft is not excessive, and that the burning fuel has time to transfer heat inside the steam room.

The stove maker’s task includes taking into account not only internal, but also external factors - the location of the pipe in relation to the roof, the characteristics of the local climate, and even the influence of the landscape.

The chimney draft can be affected by tall buildings and trees located nearby, as well as by incorrect choice of chimney height

For gas heating systems due to their increased fire hazard, the calculation of the chimney parameters is carried out by specialists who develop the boiler. The dimensions are indicated in the technical data sheet and are mandatory.

In private construction, where the combustion is carried out predominantly with solid fuel (firewood, coal, peat or fuel briquettes), you can adhere to the following rules, which will ensure correct work any oven:

internal cross-sectional area of a rectangular chimney in stoves closed type should not exceed the cross-sectional area of the blower;
the internal cross-sectional area of the pipe in open-type stoves and fireplaces is calculated in a ratio of 1:10 in relation to the firebox.

It is believed that if the chimney structure has a rectangular shape, the ratio of the short side to the long side should be equal to 1:2. In this case, the minimum permissible cross-sectional size of the channel is 14 x 14 cm.

The size of the brick chimney channel wall should not be less than 14 cm

An important factor is the height of the pipe. Correct calculation allows:

optimize the operation of the chimney and achieve better efficiency indicators for heat transfer;
ensure safe operation of the heating device, eliminate the leakage of harmful gases due to weak draft;
ensure fire safety - if the draft is excessive, sparks and flames may fly out of the pipe.

In general, the height is determined in accordance with SNiP 2.04.05–91:

the minimum distance from the grate to the top point of the chimney (excluding the protective umbrella) is 5 m;
the optimal distance is 6 m.

Such parameters ensure stable draft, i.e. the design of the chimney allows you to create a pressure drop sufficient to operate the stove at any time of the year. But in each particular case it is also necessary to take into account:

There is such an unpleasant phenomenon as backdraft. This term refers to the movement of smoke in the chimney in the opposite direction - from the chimney duct into the room. There may be several reasons for this, but the main one is the wrong position chimney. As a rule - underestimated.

An error in choosing the height of the chimney often leads to backdraft

Excess draft can always be eliminated by adjusting the air flow in the ash pan and smoke valves. Insufficient traction is exacerbated in several ways:

Pipe extension.
Cleaning the inner surface of the chimney duct.
Installing a deflector.

The deflector not only increases draft, but also protects the chimney channel from moisture, debris and birds and bats settling in it.

According to experts, by installing a deflector on a chimney, draft can be increased by 15–20%

Video: how to calculate the height of the chimney

You will learn about which pipe is best to choose for a chimney, as well as the advantages and disadvantages of materials in our material:.

Making a brick chimney with your own hands

Knowing the features of chimney construction and having in hand finished project, you can start self-construction smoke exhaust channel.

Materials and tools required for chimney construction

To build a chimney yourself, you will need the following tools:

trowel and mason's hammer;
hydraulic level, plumb line (or construction laser level);
construction bucket for mixing mortar;
building rule, jointing;
electric mixer (you can use a regular drill with an attachment);
measuring instruments - tape measure, ruler.

To build a chimney, standard tools from a mason's kit are required.

During the masonry process, you need to make smaller building elements from brick - brick plates, a quarter of a brick, a half, etc. An experienced mason copes with the task with one well-timed blow of a hammer. A novice stove maker who does not have such skills can use a grinder with a diamond blade. With its help, cutting of any required shape becomes easily accessible, although accompanied big amount dust.

Some stove makers successfully use a template made of wood or metal for masonry. The template allows you to strictly adhere to the dimensions, which is especially important for the internal hole of the pipe.

In addition, you will need materials:

red brick (in no case white - silicate) solid, hollow, fireclay, clinker;
cement mixture (can be ready-made or prepared independently from sand, cement and clay);
a set of smoke valves or views;
sheet metal or roofing.

Preparatory work before making a chimney

Before directly starting work on laying a brick pipe, it is necessary to carry out certain preparatory work:

During operation, hands come into contact with chemically aggressive solutions; it is recommended to use protective gloves to protect them.

When performing work on the roof, it is necessary to observe personal safety measures and also use scaffolding and rope belay.

At the construction site there should always be a first aid kit with first aid for wounds and bleeding. Sometimes the chimney is not located in the center of the room, but is in contact with load-bearing wall. This situation is often observed during the construction of fireplaces. In this case, you can use the wall structure of the chimney. It is pre-installed during the construction of the main wall. It is appropriate to note here that among stove makers there is a common classification of chimneys according to design characteristics:

Brick overlays. Chimneys installed directly on the stove masonry.
Brick indigenous. Pipes located separately from the furnace, standing on a separate foundation. They have the shape of a riser.
Prefabricated. Individual blocks made of refractory concrete that are stacked at the site where the chimney is installed.
Wall. They are built into a load-bearing wall, significantly saving space and volume of premises. However, it should be taken into account that it is not advisable to install wall pipes in external walls. Contact with cold outside air sharply reduces the efficiency of such a chimney in terms of heat transfer.

In wooden houses, the junction of the pipe with the combustible elements of the building is accompanied by a thickening of 1–1.5 bricks. To avoid fire, joints are additionally laid with asbestos or felt sheets. The felt is pre-soaked in a liquid clay solution.

Step-by-step instructions for building a brick chimney

The construction of a chimney involves laying bricks in strict accordance with the plan for the arrangement of material in each row - the order. This plan must be drawn up when preparing a project for the construction of a smoke exhaust duct.

Each row of chimney masonry has a strictly defined arrangement of bricks

We can only add that for the best bonding of bricks with mortar, it is recommended to adhere to the following installation settings:

The mortar is applied in a layer of 1.5–2 cm, the brick is wetted and coated with the mortar. After installing the masonry in place, the brick is pressed down so that the final thickness of the seam is 1 cm.
When laying each brick, it is necessary to check its position horizontally and vertically, and also maintain a joint thickness of 1 cm
As the masonry progresses (after 5-6 rows), it is recommended to do mopping - grouting the seams between the bricks inside the chimney duct. A smooth internal surface will ensure good passage of exhaust gases and reduce the risk of soot deposits. Grouting can be done with a wet cloth.
Internal seams are leveled and rubbed with mortar as the masonry progresses.
The installation of a smoke damper is usually carried out between the second and third rows of bricks. But this is not a strict rule - you can adjust the installation location depending on the situation. Immediately after installation, the valve is closed so that the cement mortar does not fall into the furnace.
A separate valve is installed for each smoke channel
In the external masonry - on the roof - a mortar with increased strength and moisture resistance characteristics is used. To do this, the mixing proportion is changed, increasing the cement content (instead of 1/4, make 1/3). Moreover, the cement selected is grade M 500 or M 600. For the head, not a cement-sand composition, but a cement-clay composition is often used. It is made by adding 1 liter of cement to 10 liters of sand-clay mortar, which is used for laying the furnace.
When using hollow bricks, the internal cavities are filled with cement mortar
It is important to keep the solution clean. It is unacceptable for debris, especially of organic origin, to get into it.
Straight sections of the chimney are laid out plumb. To do this, strong silk threads are pulled in each corner and aligned vertically. The right angle is controlled using a square every 4-5 rows.
It is convenient to control the vertical position of the chimney walls using cords stretched in each of the four corners

Video: DIY chimney for a fireplace

Features of the operation of brick chimneys

After the construction of the chimney is completed and the pipe has been successfully put into operation, it is advisable to familiarize yourself with the features of using a brick stove. In order for the heating unit to serve for a long time and without accidents, it is necessary to follow simple but important rules.

The main enemy of brick is sudden temperature changes. It is better to heat more often, but for short periods of time. It is not recommended to make more than 2 fuel loads per firebox. This is especially true for coal, the combustion temperature of which exceeds 1000 degrees.
Timely cleaning of the pipe from soot unlimitedly extends the service life of the chimney duct.
If cracks occur on the stove body and chimney in particular, measures should be taken immediately to eliminate them. Neglected cracks tend to progress quickly and pose a threat not only to the integrity of the brickwork, but also to human health. Carbon monoxide, which is colorless and odorless, but poisonous to all living things, penetrates into the living space through small cracks.
The slightest malfunction in the doors of the firebox or ash chamber (ash chamber) first significantly reduces the heat transfer of the stove, and then leads to an avalanche-like accumulation of soot on the chimney channels. If you find a door, view or valve that does not close tightly, you should immediately repair or replace it.
At least once a year it is necessary to carry out preventative maintenance on the furnace. It is best to do this at the end of summer, before the start of the heating season. A daily preventative procedure includes opening the blower door for 15–20 minutes. This simple action will allow you to briefly create maximum draft, which will pull the soot deposited on the walls into the external environment.
The use of damp firewood has an adverse effect on the cleanliness of smoke ducts, especially in winter time. It is more rational to use fuel briquettes, the humidity of which is much lower. Firewood should be prepared ahead of time - drying wood naturally is a long process (from a year to two).

Chimney cleaning and repair

For cleaning pipes they are used as traditional ways, and modern, based on the achievements of technological progress.

From time immemorial, stove maintenance was carried out by people whose profession was called chimney sweep. Today, finding a professional chimney sweep is problematic. They were replaced chemicals, which, however, are also often called “Chimney Sweep”.

Finding a professional chimney sweep today is very difficult; this profession is a thing of the past.

Thus, a product called “Log Chimney Sweeper” has proven itself well. It contains salts copper sulfate and other active chemical compounds. Burning in the firebox, the vapors of these substances interact with carbon deposits deposited on the walls of the pipe. Under the influence of heat, the reaction continues for several weeks and leads to the fact that the solid structure of the soot crumbles and, falling back into the firebox, burns. According to manufacturers, using “miracle logs” twice a year allows you to completely remove soot from the pipe. The consequence of this is good traction and high percent heat transfer of the furnace.

Manufacturers of the “Log Chimney Sweeper” product claim that its use twice a year allows you to completely clean the chimney of soot

From folk remedies the following can be noted effective ways prevention, such as burning salt or soda once every 2 months (about 0.5 kg per firebox). The powder is poured into the combustion chamber at the moment when the firewood is well lit and the temperature is at its maximum. After this, you need to close all the doors tightly, as the reaction can be quite violent.

Dry aspen firewood helps clean the chimney well. The fact is that the aspen tree burns with large release heat, the flames are long and penetrate deeply into the passages.

If you don’t have aspen or soda, you can use potato peelings. To do this, you need to accumulate about half a bucket of potato peels. When burned in a firebox, the released substances bind the soot and cause it to burn to the end.

The combustion temperature of aspen wood reaches 800 degrees, so the soot on the walls of the chimney burns out

When performing work on installing chimneys, especially in the area of installation of the neck, otter and cap, you should carefully observe safety standards. If you work carefully and follow the necessary instructions and technologies, you can easily build a brick chimney with your own hands.