How to install a pipe on the roof. Installation of a chimney on the roof. Sheet metal sheathing

Heating devices are a necessary attribute of any residential building, providing a comfortable temperature for life during the cold period, which lasts 9 months in most regions of Russia. However, additional comfort comes with a certain degree of fire risk. Therefore, special attention is paid to the chimney, through which smoke and combustion products are removed from the heat generators and removed to the outside of the room. This article will tell you how to bring the chimney through the roof in compliance with all safety requirements.

As a rule, the work of a stove-maker or an installer of gas equipment does not include chimney installation services; the homeowner must provide the passage of the chimney through the roof on his own. The imaginary simplicity of the task makes home craftsmen refuse the services of professional roofers. However, poor-quality output of the pipe to the roof threatens with serious consequences:

Through the leaky passage of the pipe, moisture seeps into the masonry, gradually destroying it.
High humidity inside stimulates the spread of molds and fungus. Spores of some types of fungus are dangerous for the human condition, so it is not safe to use an infected tube. In advanced cases, both the chimney and the stove masonry are subject to replacement.
The penetration of water into the passage of the chimney pipe through the roof reduces the thermal insulation properties of the insulation by half. Moreover, after the thermal insulation layer has dried, its characteristics will never return to the previous level.
Even the truss system suffers from poor-quality removal of the pipe through the roof, since moisture penetrating into it through a leaky passage leads to decay and destruction.
Slots near the pipe passage disrupt the normal air circulation inside the attic, leading to increased energy losses and heating costs.

By the way, not only stove chimneys are brought to the roof, but pipes from gas boilers and ventilation outlets are also placed there, for the installation of which they use the same methods.

The choice of the location of the chimney outlet and its height

The first condition for a high-quality outlet of the pipe through the roof is the correct placement of the chimney on the roof. The functioning of the entire heating system depends on this factor, therefore, in order to avoid errors, installation is carried out in accordance with construction and fire safety requirements:

Chimney pipes are placed in the immediate vicinity of the highest point of the roof, at a distance of 1-1.5 m.
The recommended height of the chimney relative to the roof ridge to ensure normal stove draft is 0.5-1.5 m.
The greater the height of the chimney, the greater the traction force in the furnace or gas boiler it provides.
The lower the chimney is located on the slope, the longer it must be in order for the recommended height of the chimney above the roof to meet the recommendations.
Parameters such as the height of the chimney, the diameter of the section are selected according to the recommendations of the manufacturer of the thermogenerating device or on the basis of a calculation.
The chimney consists mainly of vertical sections of pipes, the length of horizontal segments should not exceed 1 m.
The outlet is placed between the elements of the truss system so as not to violate its integrity.

The main difficulty in passing the pipe through the roof is that during the passage of smoke, the temperature of the walls rises, which poses a risk of ignition of combustible materials of the truss system.

Elastic penetration

Most often, in private construction, they are faced with the installation of metal pipes of circular cross section. To ensure the tightness of the passage, use a special device - an elastic penetration. This product is made of high-strength silicone or rubber, having the shape of a funnel with a wide flange in the form of a square or circle, called an apron. Elastic penetration, due to its properties, takes any shape, adjusting to the angle of inclination of the slope. It withstands extreme high or low temperatures, exposure to harsh chemicals and has a wide palette.

When purchasing an elastic penetration, they are guided by the diameter of the pipe and the color of the roofing material. Universal models, in the form of a stepped pyramid, are suitable for any size, adjustment is carried out by trimming the penetration to the desired level. Installing an elastic apron on the roof is very simple, you need to put it on the chimney passage, put a metal circle with holes for fasteners, process the joint with a fire-resistant sealant and fix it with a screwdriver. For roofs with steep slopes, a special type of plastic penetrations is used with a given flange mounting angle.

Metal spigot

In hardware stores, you can find another type of penetration for round pipes - a metal pipe through. It is used to pass the chimney through a roof that does not have a relief. The prefabricated alloy steel spigots have a standard roof angle, which is matched to the roof slope. To complete the installation, you must:

Cut a suitable hole in the roof. To do this, using a marker, markings are applied to the surface of the roof. Depending on the roofing material, cutting is performed with a grinder or sharp scissors, stepping back 1-2 cm inside the circle.

Remove the waterproofing and thermal insulation material from the hole made, freeing the passage for the chimney. If necessary, remove the elements of the crate by carefully sawing them off.
On the underside of the roof, fix a sheet of fire-resistant material with a hole of the required diameter of such an area that there is a margin of 15-20 cm on each side of the chimney.
Push the pipe module into the hole, dock it with the laid chimney, tightening the junction with a clamp.
Put the outlet pipe on the pipe, fixing it on the slope surface with fire-resistant sealant and self-tapping screws with a rubber cap.
Attach the pipe with new segments so that the height of the chimney reaches 0.5-1.5 m above the level of the ridge.

Some craftsmen prefer to use a different method - they pre-solder the chimney pipe into the passage pipe, cover it with thermally insulating material, for example, stone wool, and only then this design is mounted in the passage.

Conclusion of rectangular and square pipes

Made of brick, most often square or rectangular, so other methods are used to bring it to the roof. This task is for an experienced kiln master, and not a home craftsman, because a special masonry technique is used in the process. When the chimney approaches the roof, a hole of the appropriate size is cut out in it with an allowance of 2-5 cm, through which the stove-maker leads out. Although heat-resistant brick perfectly retains heat inside the pipe, asbestos sheets are chipped from the inside of the passage to protect the rafters from fire.

A soft waterproofing tape on a lead or aluminum base is attached to a brick pipe using a metal profile, the lower edge of which is fixed to the roof with a sealant. After that, the unsightly waterproofing is closed with a special decorative apron. It consists of four additional parts and is installed under the roofing material, making the passage neat and well protected.

Output box installation

The roofing device consists of layers of several materials, the refractory qualities of which are expressed in different ways. While most roofing materials are non-flammable and non-combustible, truss systems traditionally made from timber do not. In order to safely lead the chimney through any material, a passage box is mounted:

First of all, a box is purchased or made from a refractory material, for example, metal or asbestos. The size of the box is selected in accordance with the cross section of the pipe, so that there is at least 15 cm between their walls.
After making the hole, a box is installed in it, the upper edge is aligned with the level of the roof slope.
The chimney is led out through the hole in the duct. The edges of the waterproofing film and vapor barrier are glued to the pipe using a fire-resistant sealant and reinforced tape.
Expanded clay is poured inside the box or stone wool is laid to insulate the chimney. Thermal insulating materials are placed taking into account the fact that they should not impede air circulation.
Outside, the chimney pipe, depending on the shape and roofing material, is finished with an elastic penetration, a decorative apron or a metal pipe.

A well-made chimney outlet does not spoil the appearance of the roof, does not allow moisture to pass through and is safe from the point of view of fire safety standards. Follow the correct technology for passing tubes through ceilings to protect yourself and your property.

Video instruction

During the construction of the furnace, special attention should be paid to the correct arrangement of the chimney pipe, without which the long-term operation of the heating structure is impossible. Since the services of a professional stove-maker are expensive, it is not uncommon for budget-conscious homeowners to decide to install the chimney on the roof themselves.

Features of the structural device of chimneys

It is required to install chimneys in houses where there is a Russian stove or solid fuel fireplaces. If you want to have a real heating structure made of brick or stone, you need to choose the right location for its installation. In ancient times, people first of all laid out the furnace, and only then erected the walls.

In order not to provoke the occurrence of a fire hazard situation, it is necessary to adhere to a number of rules. So it is impossible to place a large number of wooden ceiling elements above the stove, since there is a high air temperature there, which is fraught with big troubles, up to the ignition of beams and ceilings.

The performance of the smoke exhaust structure depends on how straight the chimney is located on the roof and on its length. To ensure the required traction force, it is necessary that the air blow over the chimney at the location of the ridge or not far from it.

It is impossible to allow rapid cooling of gases appearing in the furnace shaft as a result of fuel combustion. Therefore, it is necessary to ensure not only the correct installation of the chimney on the roof, but also its high-quality insulation. If this is not done, condensation will constantly appear at the point of contact of warm air masses with cold ones - it will eventually saturate the chimney and begin to descend lower, destroying the structure and clogging it.

The choice of materials for the chimney

When building a furnace, you need to properly purchase building materials, this is the only way to ensure the optimal temperature regime for the smoke exhaust channel and a long service life. Materials must heat up quickly.

For the construction of chimneys use:

ceramics;
metal;
asbestos mortars.

Each of the listed materials has its drawbacks - this does not allow us to call their choice ideal. Therefore, when purchasing this or that product, you should consider how the product is suitable for installing a chimney on the roof.

For example, metal structures look good, but only if a wall-mounted chimney is built. But to make a root model of a metal pipe will be very expensive.

When building the internal parts of chimneys, bricks or modules are used - materials that are resistant to fire and durable. For external sections of the structure, it is better to use asbestos-cement products.

Variety of chimney schemes

When building a chimney, one of the existing schemes is used, according to which the choice of building materials is made. If you choose it correctly, you can significantly save money and time for work.

Pipe layouts, taking into account the type of construction, are:

hidden - they are mounted in the ventilation ducts inside the walls of buildings;
mounted - the chimney is connected to the outlet of the air ducts of stoves or fireplaces;
external - pipes are installed on the facade or roof;
indigenous - a vertically located riser is mounted on its own foundation.

Before leading the pipe outside the building, they first equip the internal hidden areas, and then proceed to the construction of the external chimney. Root or wall-mounted schemes involve the withdrawal of chimney systems through the roof or attic.

Independent construction of chimneys

The technology for arranging a smoke channel has much in common with the installation of a conventional duct. The difference lies in the presence of more stringent requirements for the operation of the chimney. Therefore, the process of arranging pipes for furnaces requires accurate calculations, the choice of building materials, parts for fasteners, refractory putties and other things.

Pipe modular

In the event that the chimney is planned to be laid in the wall of the house, this nuance should be taken into account at the stage of building the wall, otherwise the hole will need to be punched with a jackhammer. It is possible to equip the furnace air duct in an already equipped ventilation duct, but as a result, the fire safety of the smoke exhaust structure will significantly worsen.

To implement a hidden pipe scheme, you need to use the services of an experienced architect, since during the operation of the furnace temperature deformations are possible - the dimensions of the channel increase from exposure to hot gas, thereby exposing the walls to destructive processes.

Sections of the chimney inside the supporting structures can be equipped from multilayer blocks. They are placed over the entire surface of the wall, using a temperature-resistant adhesive for fixing. This material is able to level thermal deformations, thanks to damper gaskets, and thereby ensure the integrity of the building.

The main advantage of this design is that it does not require pipe insulation on the roof of the house - the channel will go outside above the roof level inside the gable.

Mounted steel chimney

To install steel chimneys, special skills and time-consuming are not required, so they are often preferred by homeowners, and such structures are relatively inexpensive.

In doing so, it must be taken into account that:

Any metal pipe must consist of at least two parts, and be disassembled accordingly. After the first section burns out from high temperatures in a few years, it will not be necessary to change the entire structure, but only its section.
Where the chimney will be led out through the roof and wall, refractory insulation is laid, otherwise the building may ignite.
The section of the pipe located in an unheated room must be insulated with high quality so that cold air masses do not cool the gas and thus do not affect the performance of the heating unit. As a result, condensate will not collect on the surface of the pipe and it will not rust.
Be sure to equip the waterproofing of metal pipes with non-combustible materials.

Mount the metal attachment structure in stages:

The first knee is put on the screen nozzle or on the outlet of the furnace air duct.
The second ring is taken out through the attic into the room and fixed on a refractory spacer.
Connect both knees.
The third segment is led to the attic through a through opening in the roof. The place where the pipe exits to the street is covered with a spherical casing.

Root brick pipe

This type of stove chimney made of bricks will last for many years. They equip the root pipe on the foundation, which is laid separately during the construction of the basement.

The installation technology of this chimney is more complex than that of a built-in metal structure. The fact is that the root pipe must withstand the longitudinal load from the weight of the entire unit, so it is laid out from fired bricks.

Building feature:

For the construction of a chimney, a hole the size of a brick or half a brick is left. To lay out one layer, 4-6 bricks will be enough.
The layers are laid out so that the bottom joint of the row is under the whole brick.
Before you bring the chimney through the roof, in the place where it passes through the ceiling, a special module is made - to shift the axis of the section penetrating the roof relative to the axis of the part of the chimney located in the room.

The design of this type is complex, and it is mounted when there are no other options.

External chimney

A pipe mounted from metal or asbestos-cement modules is installed along the facade of the building, moving in the direction from bottom to top.

External structures have features:

in the place where the pipe enters the building, a hole is made, through which the horizontal segment of the chimney is then removed;
the junction of the horizontal and vertical sections is made in the form of a tee, in which one part is closed with a plug. This element is used when cleaning the chimney;
the pipe is attached to the facade using a detachable type of metal clamps. The lower part of the chimney is reinforced with a superstructure specially erected on a separate foundation.

Pipe exit through the roof

When removing the smoke exhaust structure through the roof slab, it is necessary to ensure:

protection of the place of its exit so that moisture or debris does not get inside the building;
reliable fire safety.

In any case, it will be necessary to build a truss system with an interrupted beam or no supporting beam at all. Therefore, additional supports will be needed, but they can not always be done, especially if there is an attic.

The chimney should not be led out at the point where two roof slopes meet, since then it is practically impossible to ensure a good connection and insulation.

When carrying out construction work, it is necessary to take into account some important nuances:

Between the roof and the rafters maintain a distance of at least 25 centimeters.
In the case when the mansard gable roof is built from flammable building materials, a gap of 13 to 25 centimeters is needed. If in this case non-combustible products were used, a few centimeters are enough.
The chimney must be removed from the crate.
To protect the thermal insulation layer from moisture and exposure to hot steam, it is necessary to equip a continuous heat and vapor barrier, but always with a small gap.
The ideal solution would be to build a box of metal sheets in the area adjacent to the chimney. It is located at a distance of about 15 centimeters from the pipe. The existing gap is filled with non-combustible thermal insulation, which is, for example, stone wool.

Chimney structure insulation

When installing a chimney on the roof, an insulated chimney has several advantages:

Increases the efficiency of the furnace, and several times.
The level of safety during the operation of the unit becomes higher.
The oven is aesthetically pleasing.

To make a three-level waterproofing on a gable roof, you need:

First, prime the structure with polymer mastic and glue the superdiffusion membrane, wrapping its edges, which will ensure a tight joint between the chimney and the roof, even when moisture gets in.
Install metal corners on top and bottom. The upper metal sheets are laid on the lower ones so that the moisture is directed downward by gravity. Experts recommend laying the bottom tie up to the roof overhang.
On the crate, nail additional bars to fix the corners.
Treat parts with sealant.
Fix the resulting structure with dowels.
Lay end-to-end ondulin, using bituminous mastic for processing seams.
Place a special apron made of ceramics, plastic or other materials in a circle over the ondulin, using the onduflash for sealing.

In order to perform the installation qualitatively, you need to have knowledge of how to properly install the pipe on the roof and have the appropriate skills. The arrangement of the chimney is associated with great risks, so you should not forget about safety measures when work is done on the roof of the house.

If it is decided not to build a separate chimney box at the bottom, it is necessary to provide a gap between the chimney structure and the combustible materials used for the walls.
The section of the chimney that will be located outside must be made without joints. When this is not possible, the joint should be made above the pipe exit point from the ceiling, without coming into contact with the battens and roofing. The joints are tightened with iron clamps, covered with asbestos material and fixed.
If you want to lay out a brick chimney, you need to purchase a special baked brick, using clay or strong cement grades for masonry.
If you are not sure that you can build a brick chimney yourself, then it is better to purchase a finished structure. The homeowner will only have to study the information on how to fix the pipe on the roof. Today, insulated and protected chimney systems are commercially available that do not need to be covered with asbestos and treated with mastic.
To improve the fire protection of the structure, you need to put a visor on it, which protects against accidental ingress of sparks and precipitation.

Heating devices that provide a comfortable thermal regime in the house are a severe necessity. The explanation for this lies on the surface, in most regions of our country the winter period lasts about 9 months, and that is why stoves, fireplaces, etc. are installed in many houses. But it must be remembered that such devices are a source of increased danger and cases when a fire occurs due to improper chimney design. Properly executed passage of the chimney through the roof will ensure maximum safety of the building.

Rooftop passage. View from the attic

What threatens the wrong chimney device?

Before running the chimney through the roof, the homeowner must understand what consequences he can expect if there are errors made at the design or direct installation stage.

If the pipe on the roof does not provide the necessary tightness, then the moisture that will accumulate there will sooner or later lead to the destruction of the brick chimney body. The presence of excess moisture in the chimney creates favorable conditions for the reproduction of mold and other harmful microorganisms. The ingress of water into the chimney leads to a decrease in the parameters of the insulation and after drying this material will never recover. In addition, as a result of errors made during the installation of the chimney, the rafters may also suffer. Since moisture that has entered the chimney can lead to the development of foci of decay on their surface. One of the most common mistakes in arranging the exit of the chimney is the presence of gaps, leading to a violation of the air movement inside the roof.

Only a small list of troubles is indicated that a homeowner who decides to independently carry out the passage of the chimney through the roof can expect. Therefore, it makes sense to invite specialists to perform such work, who can both choose the right place and decide which way the chimney pipe exits through the roof will be optimal.

How to choose a place for the output of the pipe

In order to perform the correct passage through the roof, it is necessary to observe a number of simple conditions defined by the rules. The flue pipe must be placed at a distance of 1 to 1.5 m from the top of the roof. The height of the pipe relative to the highest point should be between 0.5 and 1.5 m. The thrust will reach its maximum if the maximum allowable pipe height is used. In general, when determining the diameter and height of the pipe, it is necessary to be guided by the requirements that the manufacturer of the heating device determines.

The chimney on the roof is a set of pipes located in vertical and horizontal planes and drawn through the ceiling. In this case, the length of horizontal sections should not exceed 1 meter. The pipe outlet must be placed between the components of the truss system in such a way as to reduce the likelihood of a significant increase in the temperature of the surrounding elements. Otherwise, the prerequisites for the appearance of a fire source will be created.

Penetration for a chimney pipe - when is its device required?

The passage through the roof is performed in the following cases:

construction of a new building;
roof overhaul;
arrangement of heating devices, including stoves, in the existing building.

During the construction of a new building, there are no difficulties with the arrangement of the chimney. All necessary solutions are laid down at the design stage. Questions about how to run the chimney through the roof begin to arise when the homeowner decides to install an additional heat source (fireplace, boiler, etc.). He must solve many issues related to the arrangement of hydraulic insulation and the implementation of measures related to ensuring the fire safety of the structure. Of course, he must know how to correctly bring the pipe to the roof.

By the way, as an option, some owners of suburban real estate equip chimneys passing along the walls of buildings with their own hands. This solution is acceptable if the installed thermal equipment runs on liquid fuel. Residents will be deprived of the opportunity to inhale fumes emanating from the fuel and its combustion products.

Consequences of going through the roof

The passage of the chimney through the roof must ensure fire safety. The gases generated during the combustion of fuel create a high temperature in the chimney, which can cause the roof elements to ignite. This is especially true for systems constructed from materials with low fire resistance. So, if the supporting system of the roof is made of wood, then it is necessary to mount an additional crate at the place where the pipe passes.

Considering that many roofing materials contain polymers that are not highly resistant to fire, the pipe must be protected by thermal insulation and the distance between it and the edge of the material that can catch fire must be at least 13 centimeters. If the pipe is not equipped with thermal insulation, then this distance should be increased to 30 cm.

The passage of the pipe through the roof violates the integrity of the coating, including layers of thermal and hydraulic insulation. If you do not provide high-quality cutting of the roof around it, then, most likely, the insulation will get wet, with all the ensuing consequences.

In addition to reducing the parameters of hydraulic and thermal insulation, there is a decrease in the strength of the truss structure. This can happen if the arrangement of the chimney is done by hand in an operated building.

Options for the passage of a brick chimney through the roof

There are several ways to bring the pipe through the roof. If the pipe is made of brick, then a hole must be made in the roof, the size of which should be 25 centimeters larger than the size of the chimney section. If the roofing material is not combustible, then this size can be reduced. The main thing is the correct passage of the chimney through the roof.

The passage through the roof, lined with tiles, is additionally equipped with an additional structure, consisting of rafters and battens. A non-combustible material must be laid between the chimney and wooden structures, as a rule, mineral wool is used for this. In addition, the wood used in the arrangement of the roof must be treated with compounds that prevent them from burning and rotting.

IMPORTANT! If, when arranging the chimney outlet, it rests against the ridge beam, then it must be cut, and the free ends should be installed on vertical racks.

On the roof, it is necessary to make a metal apron, which with one edge must be wound onto the chimney itself. And the other end should be hidden under the roofing material. This design is acceptable for chimneys located at a distance from the ridge. If the pipe is located in the immediate vicinity of the ridge beam, then a protective apron must be placed under it. At the same time, it must be fixed with fasteners and treated with a moisture-resistant sealing compound.

Wiring with elastic materials

As usual, during the construction of private houses, one has to deal with the installation of pipes made of metal. To ensure the tightness of the passage of the pipe through the roof, a device called elastic penetration is used. For the manufacture of this device, polymeric materials are used, for example, silicone or rubber. This detail is made in the form of a funnel, at the base of which a square or round flange is formed. The physical and technical properties of this part allow it to take the form that the slope forces it to take. In addition, the elastic penetration is resistant to high temperatures, chemically aggressive substances, etc. The use of various pigments in the manufacture of this part allows them to be produced in various colors.

Running the chimney through the roof is an important part of the installation.

When choosing an elastic penetration, the consumer should be guided by the diameter of the pipe and the color of the roof. Such details are in the form of a funnel or pyramid. They fit most chimney diameters through metal tiles and other materials.

The installation of this part is quite simple. To do this, it is necessary to cut a hole in its body equal in size to the diameter of the pipe. Then it is necessary to put it on the pipe and, using a metal ring, in which holes for fasteners are made, fix it to the roof surface. Of course, the junction of the outlet must be treated with a flame-resistant sealant or a chimney roof sealant must be used. For roofs with a steep slope, specially made elastic cones are used. By the way, such details are used in the arrangement of the chimney through corrugated board.

metal pipe

On the construction market, you can find another version of these products, made from a metal sheet of alloy steel and designed to lead a chimney. Finished products, as a rule, are performed with a standard slope angle. They are used for roofs on which flat roofing material is laid. To install this part, it is necessary to cut a hole of the required shape in the surface of the roof. An angle grinder or roof shears can be used to make the hole. After that, it is necessary to remove layers of hydro and thermal insulation from it. On the reverse side of the roof, it is necessary to fix a sheet of fire-resistant material, in which a hole has already been made in advance.

Then, the chimney component must be inserted into the holes made, docked with the already installed chimney module. A clamp must be put on and tightened at the connection point. The outlet pipe must be installed on the chimney pipe and fixed on the slope surface. In this case, we must not forget to treat the junction with a sealant resistant to fire. After the last output segments are installed on the assembled connection, and their height is 0.5 - 1.5 meters, the work on creating the passage can be considered completed.

Rectangular pipe outlet

Stoves, fireplaces and some other heating systems most often have rectangular (square) chimneys. To correctly remove the chimney, you must perform the following operations.

As the chimney is brought to the roof, a hole is cut out in it, the dimensions of which should have an allowance of 2–5 cm, to the side of the hole. Through it, a conclusion to the roof will be made. The equipped passage must be lined with asbestos or mineral wool. For this, you can use asbestos sheets. They will protect the passage unit, for example, through an ondulin roof, from fire under the action of high temperatures emanating from the chimney. After the pipe is brought out into the street. Around its base, it is necessary to lay a layer of waterproofing and close it with an apron made of bent aluminum sheet. These sheets are called additional elements, and they must match the color of the roofing material in color.

Lead box

Finishing the pipe on the roof can be done using a special box. The roof is made of several types of material, which have different resistance to flames. And therefore, for a safe output through a wooden wall, a special box is equipped on the roof. It is made of fire-resistant material with dimensions that must match the size of the chimney. The distance between the walls of the box and the outlet pipe of the chimney must be at least 15 cm.

After installing the box in its place, its upper edge is compared with the level of the roof slope. To increase its protective properties, expanded clay or similar material is poured into the space between the chimney and the box.

The system for the safe removal of combustion products from furnaces, boilers, instantaneous water heaters is one of the most serious problems solved during the installation of such equipment. Moreover, safety issues are very diverse: this includes ensuring the correct operation of the heating equipment itself, and eliminating the likelihood of building structures igniting from overheating, and guaranteed prevention of toxic gases entering the premises. All this range of problems can be solved by competent, in strict accordance with the requirements of technology, installation of modern kits.

Such products are produced in a wide variety of components, which allows you to assemble chimneys of any degree of complexity, optimally fitting into the architectural specifics of each particular house. A layer of insulation between the inner and outer walls can significantly reduce the volume of the pipe formed in the channel due to a sharp temperature drop of condensate, and such chimneys are very often located outside buildings, which greatly simplifies general construction and installation work.

However, quite often there are situations when the external installation of the chimney is impossible, impractical, or the owners simply refuse this approach for reasons of aesthetics of the facade of their house. The solution is obvious - to install a chimney from sandwich pipes through the roof. True, this method seems to be more difficult, if only because of the need to carry out a safe and well-insulated penetration through floors and roofs. However, there is nothing impossible in this.

What is a sandwich chimney pipe. Advantages and disadvantages of the system

The use of ordinary metal pipes as chimney channels is not a novelty - they were used quite widely before, for example, for stoves or stoves. This wave is understandable - a number of benefits before, for example, brickwork:

The installation of such a chimney does not take much time, since the installation is made from large parts.
The round section of the channel is optimal for the best traction, since it does not create unnecessary turbulence in the gas flow.
The smooth inner surface of the pipe, which does not create unnecessary resistance, also contributes to good traction, and besides, soot buildup is formed on it to a much lesser extent.

But at the same time, such a scheme also has pronounced shortcomings , moreover, so serious that they are able to outweigh all the advantages listed above.

Metal (steel in particular) has an extremely high thermal conductivity, that is, in open areas of the chimney or when it passes through unheated rooms, the gas flow will cool very quickly. And this leads to a decrease in thrust in the pipe, and in addition, the magnitude of thrust becomes highly dependent on current weather conditions.
Combustion products of any type of fuel always contain a large amount of water vapor. The above-mentioned temperature difference inside and outside the channel causes abundant formation of condensate, which causes rapid soot overgrowth of pipes and activation of metal corrosion processes.

If we are talking about corrosion, then we must not forget that the exhaust gases always contain very aggressive chemical compounds, in particular, sulfuric acid. Under such conditions, the service life of pipes made of metal that is not resistant to corrosion will be very limited - they will quickly burn through. And this is a direct path to the fire.
Finally, the metal's high thermal conductivity means that pipe indoors and through building structures will always be a potential safety hazard. Thus, enhanced precautions will be required to prevent overheating and ignition of the building structures of the house, in order to exclude thermal burns if the chimney is accidentally touched in the areas of its passage through the premises.

Chimney prices

To preserve all the advantages mentioned, but at the same time to minimize the disadvantages of a metal chimney, a system of insulated sandwich pipes was developed. In fact, this is a "pipe in a pipe", separated by a layer of heat-resistant thermal insulation material. An exemplary device diagram is shown in the illustration below:

1 - the chimney itself. Special requirements are imposed on it - it must be made of high-quality steel with pronounced resistance to corrosion, and the manufacture of the pipe must only be welded, using argon welding in a protective gas environment (TIG technology). A pipe with a seam seam is absolutely not acceptable.

2 - outer metal casing. Most often it is also made of stainless steel. However, budget options are also on sale - from galvanized steel. In addition, it is possible to purchase sandwich pipes with an external decorative coating, for example, if it is necessary to maintain the appearance of the facade or the interior design of the premises through which the chimney passes.

3 - thermal insulation layer. As a rule, this function is performed by heat-resistant mineral wool made of basalt fibers, with a density of 120 to 200 kg / m³. The thickness of the insulation layer may vary - it is selected in accordance with specific conditions: the type and power of the heater, the layout of the chimney, the climatic conditions of the region and other criteria.

4 - pipes are equipped with special elements for quick and reliable installation. In most cases, this is a system of sockets and constrictions, which, when connected, together with the sealants used, form a sealed assembly. For greater reliability, additional tightening of these connecting nodes with the help of clamps is provided. There are other ways of mounting, for example, in some models, flange connections with threaded fasteners are provided.

As a result, the chimney structure assembled from such modules acquires new positive qualities:

Due to the stability of temperature indicators inside the chimney duct, regardless of the weather and the location of a particular section of the system, stable even draft is ensured.
The formation of condensate, although not completely excluded, is still minimized.
The outer surface of the sandwich pipe does not heat up to critical temperatures, and will not pose a danger to people living in the house, if it is necessary to pass it through the premises of the upper floor, attic, attic.
It becomes much easier to organize pipe penetrations through ceilings and roofs. In addition, many manufacturers immediately provide special feed-through modules of the required size in the manufactured kits.
The chimney system itself, assembled from sandwich modules, does not have a significant mass, and it is quite possible to arrange it according to the plug-in principle, that is, the chimney rests directly on the stove or boiler. It will not exert excessive load on the supporting structures of the house when attached to them.

A wide variety of components for assembling such a system allows you to create a chimney of the required degree of complexity, diameter, insulation thickness, height, and the assembly process itself is simple and intuitive for any technically “savvy” homeowner.

How to choose the right kit for installing a sandwich chimney

The choice of accessories for the installation of the chimney must be approached with the utmost responsibility. First of all, since the chimney will be installed indoors, with a passage through the ceiling and roof, the issues of ensuring the complete safety of its operation come to the fore. Well, it is clear that such work is carried out with the expectation of long-term use, and so that after a few years the owners are not disappointed, the purchased components must be of high quality, certified, accompanied by documented manufacturer's warranty obligations.

Prices for sandwich chimneys

sandwich chimneys

The choice always comes down to the evaluation of several criteria:

The manufacturing quality of the components of the sandwich chimney and the materials used in the production process.
The capacity of the chimney channel, that is, the cross section of the inner pipe.
The thickness of the required thermal insulation layer.
The prepared installation scheme and the parts and assemblies necessary for its implementation.

Let's go through these points in turn.

Material for the manufacture of sandwich chimney pipes

Such systems for the removal of combustion products in our time are in extremely high demand. Unfortunately, the increased demand, as it, alas, usually happens, is accompanied by the appearance on the market of low-quality products, either “without identification marks” at all, or masquerading as a particular brand.

It is clear that a self-respecting owner will not purchase obviously low-grade goods in incomprehensible outlets or from hands - there is no need to wait for quality guarantees here. But it happens that in large stores no-no, and counterfeit goods will appear. So the documentation (and the registration certificate must be mandatory) pay increased attention.

It also happens that sellers interested in selling at any price do not try to draw the attention of consumers to the features of the metal used for the manufacture of pipes. But the stainless steel outwardly looks almost the same, and often an ignorant buyer purchases a product that, in principle, is not suitable for the existing or planned operating conditions of the chimney system.

As a result, a situation becomes very likely when, after installation and, it would seem, several months of flawless operation (or even two or three years, which is also extremely short for such a design!), An outwardly “beautiful and shiny” chimney suddenly begins to show signs of leakage gases into the room. And this is already a serious signal that far from everything is in order with him, and a serious accident is not far off, fraught with burning out of the inner pipe, which often ends in fire hazardous situations.

Therefore, be sure to pay attention to the grade of stainless steel from which the inner and outer pipes of the sandwich chimney are made. If there is no mention of this, the acquisition should be categorically abandoned.

The following table will help you choose. Of course, not all grades of stainless steels are represented in it, but only those that are usually used for the manufacture of sandwich chimneys and are most often found on sale.

Stainless steel grade according to AISI (USA), EN (EU), DIN (Germany), GOST (Russia) standards				Brief description and recommendations for use
AISI	EN	DIN	GOST
AISI 430	1.4016	X6Cr17	12X17	One of the most affordable options. Suitable for use exclusively in non-aggressive conditions. Thermal resistance - low, weak resistance to corrosion. Poor quality welding. Suitable only for the outer casing of the chimney.
AISI 439	1.4510	X3CrTi17	08Х17Т	The difference from the previous brand is the presence of titanium additives, which increases the thermal and anti-corrosion resistance of the metal. As a material for the inner pipe of a sandwich chimney, it is permissible to use with heat generators or instantaneous water heaters that operate only on gas.
AISI 304	1.4301	X5CrNI18-10	08X18H10	This steel has good heat resistance, but resistance to acid corrosion is low. It is not used for the inner pipe of the chimney, since corrosion can eat such a pipe literally within a few months, and for the outer lining it is quite suitable.
AISI 316	1.4401	X5CrNiMo17-12-2	08Х17Н13М2	Austenitic chromium-nickel-molybdenum steel, resistant to very aggressive flue gas environments, including those with a high content of sulfuric acid. Thermal stability is average, therefore it is better to use for gas-fired equipment with a maximum temperature of combustion products up to 450ºС.
AISI 316Ti	1.4571	X6CrNiMoTi17-12-2	10X17H13M2T	Steel similar to the previous one, but with much higher heat resistance. Withstands heat load up to 800 ÷ 850 ºС, that is, chimneys with an inner pipe made of such material can be used with solid fuel equipment.
AISI 316L	1.4435	X2CrNiMo18-14-3	03Х17Н14М2	In this variety, the emphasis is on anti-corrosion and chemical anti-acid resistance, especially in the area of welded joints. True, due to a decrease in the overall heat resistance, which is limited by a threshold of 425 ºС, when this value is exceeded, the strength qualities of steel decrease sharply. Great option for any gas equipment.
AISI 321	1.4541	X6CrNiTi18-10	08X18H10T	Steel with high corrosion resistance and heat resistance. According to its parameters, it is a kind of "golden standard" for use in combustion products removal systems. The maximum temperature regime of operation is 800 ºС, that is, it is suitable for equipment with any type of fuel.
AISI 310S	1.4845	X12CrNi25-21	20X23H18	Stainless steel, which belongs to the category of heat-resistant steel, withstands, without any loss of quality, operating temperatures reaching up to 1000 ºС. It is used for chimneys installed on solid fuel pyrolysis boilers of high power.

Currently, from the countries of Southeast Asia, a stream of products made of stainless steel that meets AISI 201 - 202 standards has begun. This is often presented by sellers as a “step forward” - in the sense that the development of new technologies has ensured the production of steel, which is not inferior in its performance to the same AISI 321, but is almost one and a half times cheaper than it.

Experts in the field of metallurgy recommend not to succumb to such tricks - replacing expensive nickel with nitrogen, manganese and copper additives leads to instability of the crystal structure of the material, a high risk of cracking, and very low corrosion resistance. So this “step forward” is just a product designed for mass production, and which can only be attributed to high-quality stainless steels with a high degree of conventionality.

A few words about the thickness of the pipe walls.

You can follow the following rules:

- with a diameter of the inner pipe in the range from 130 to 450 mm - the thickness of its walls is 0.5 mm;

- with a diameter of 500 mm - 0.6 mm.

- with a diameter above 500 mm - 0.8 mm.

For furnaces, gas turbine plants, that is, where the temperature of the combustion products reaches values \u200b\u200bof more than 450 ºС, the wall thickness of the inner pipe should be 0.8 mm, using heat-resistant or heat-resistant grades of AISI 321 steel, and for high-power boilers it is better AISI 310S.
Immediately after the solid fuel heater, an uninsulated section of the chimney is installed. The optimal solution for it is a mono-pipe made of heat-resistant stainless steel (AISI 321 or AISI 316L) with a wall thickness of 0.8÷1.0 mm.
For outer casings of sandwich pipes, the requirements for steel grades are not too strict, but the wall thickness must be:

- with a diameter of up to 450 mm - 0.5 mm;

- with a diameter of 500 mm or more - 0.6 mm.

What diameter should the flue duct be?

If you look at the assortment of accessories for sandwich chimneys included in the sale, you can immediately see that they are offered in a fairly wide range of inner pipe diameters - from 110 to 300 mm. How to make a choice?

The diameter of the “mono” section (it will be discussed below) and the entire inner pipe of the sandwich chimney must be such that all fuel combustion products are guaranteed to be removed, normal draft is provided and, at the same time, the heat does not fly away literally “in pipe”, that is, a certain optimal gas flow rate was created and maintained. For heating appliances, it is customary to consider this speed equal to two meters per second.

The easiest way is to decide on furnaces, factory-made boilers - they always have an outlet pipe of a certain diameter calculated by specialists specifically for this model. This parameter, in addition, must be prescribed in the passport of the heating or water heater.

The rule is simple - the diameter of the inner pipe of the sandwich chimney, under no circumstances and in any of the sections, should not be less than the standard factory pipe. There are no restrictions on increasing the diameter, but it hardly makes any sense.

It is more difficult when, for example, a sandwich chimney is mounted on a brick oven. In this case, you can do the following.

If the thermal power of the furnace is known, then the cross section of the chimney, and hence the diameter of the inner channel of the sandwich pipe, will be easy to determine using the table.


Estimated maximum thermal power of a solid fuel furnace:	kW	up to 3.5	3.6 ÷ 5.2	5.3÷7.0
	kcal/hour	up to 3000	3000 ÷ 4500	4500 ÷ 6000
Minimum section of a rectangular chimney		140×140 mm	140×200 mm	140×270 mm
Cross-sectional area of the chimney channel		19600 mm²	28000 mm²	37800 mm²
The minimum diameter of the inner channel of the sandwich pipe		158 mm	189 mm	220 mm

If the furnace has already been operated, and the owners know the mode of its furnace developed by practice, then you can focus on these data.

For such a calculation, there is a formula:

d = √(2 × Mt × Vsp × (1 + Tout / 273) / (3600 × π))

In the formula, the alphabetic characters are:

d- diameter of the inner channel of the sandwich chimney, in millimeters.

Mt- average consumption of solid fuel per hour, in kilograms. It can be determined by dividing the mass of the fuel bookmark by the time of its complete burnout.

Vsp- the specific volume of combustion products formed, cubic meters per kilogram - a tabular value determined for the main types of fuel.

Your- temperature of the gas flow at the outlet of the chimney, degrees. you can take a tabular value (see below).

π — known mathematical constant, ≈ 3.14

Table of required values for various types of solid fuels.

Type of solid fuel	Average specific calorific value of fuel, kcal/kg	Average specific volume of combustion products from combustion of 1 kg of fuel, m³/kg	Optimum temperature at the outlet of the chimney, °С
Firewood with an average moisture level of not more than 25%	3300	10	150
Pellets, wood fuel briquettes	5100	9	150
Peat lumpy or loose, air dried, humidity not higher than 30%	3000	10	130
Peat in briquettes	4000	11	130
Brown coal	4700	12	120
Coal	6500	17	110
Anthracite	7000	17	110

Not everyone likes to do independent calculations, so below is a calculator that already contains all the necessary ratios and tabular data. The calculation process will be reduced only to entering a few values.

The exit point of the smoke channel through the roof is a complex structural unit. What are the requirements for its implementation, as well as for the height and location of the part of the pipe protruding above the roof?

Let's trust the experts

Determining the height of the chimney relative to the roof ridge

As for the height of the chimney, the regulatory document (SNiP 41-01-2003 "Heating, ventilation and air conditioning") states that at a distance of no more than 1.5 m from the ridge, the pipe should rise above it by at least 50 cm; at 1.5-3 m - be not lower than the ridge, and at a distance of more than 3 m - not lower than the line drawn from the ridge at an angle of 10 ° to the horizon. But there are no clear regulations regarding the location of the chimney on the roof. What do experts say about this?

The basic postulate: the closer the pipe to the ridge, the better. In this case, the pipe head (that is, that part of it that protrudes above the roof, which means it is in the cold zone) will be very small; thus, the likelihood of condensation in the chimney in winter is reduced. The condensate containing aggressive substances that falls inside, at the very mouth or on the protective and decorative umbrella of the pipe, is by no means harmless. It can cause poor draft in a fireplace or boiler, damage to the finishing material of the head and roof, and even shorten the life of the chimney.

When placing the pipe at a great distance from the ridge, in particular in the area of the cornice overhang, it must be taken into account that it will experience increased loads during an avalanche of snow from the roof. To protect the chimney from damage, it is imperative to mount a snow retention system on the slope

Many are of the opinion that the chimney should generally be brought to the ridge line. This facilitates the installation of the junction at the exit of the pipe, and also, since snow will not accumulate here, it practically eliminates the occurrence of leaks. However, such a solution may not always be possible. Firstly, you will need a rafter system where there is no load-bearing ridge beam, or creating a gap in the beam for the chimney and reinforcing it with supports, which is problematic in the case of a mansard roof. And secondly, accessories for the output of the pipe through the ridge are produced only for channels of square or rectangular section.

What roofers categorically do not recommend doing is to displaychimney in the valley. The implementation of the junction here is very difficult, and leaks are almost inevitable, because rainwater will pour onto the pipe from two slopes at once, and in winter a whole snowdrift will grow here. In addition, it will be necessary to seriously complicate the roof truss structure.

Chimney outlet through the insulated roof

Chimney passage through the roof

As you know, the layers of vapor and waterproofing that protect the insulation in the "pie" of the mansard roof must be continuous throughout the roof. In addition, the polymer films used for this purpose are combustible. The question arises: how to comply with the fire safety SNiP requirements, which state that there should be a distance of at least 13-25 cm between the outer walls of the chimney and roof elements made of combustible materials (depending on the type of pipe)?

Experts propose to turn the section of the roof hugging the chimney into a separate zone: on the sides of the pipe - with the help of rafter legs, and above and below it - with the help of transverse beams. Thus, a kind of box is created, the dimensions of which are determined on the basis of SNiP. The volume of the box is filled with high-density stone wool, it is a non-combustible insulation, moreover, it can do without steam and hydro protection.

The adjunction of the insulating films of the “pie” to the box is performed traditionally: they are cut crosswise, the edges are brought to the rafters or cross beams and fastened with nails (staples). Joints are sealed with special tapes or adhesives.

So that the chimney does not “pierce” the supporting rafter or fall into the valley area, its location must be clearly defined at the design stage of the building

Opening for chimney

There is another approach to the problem. Since the outer walls of modern multilayer chimneys, as a rule, do not heat up more than 60 ° C in the exit zone through the roof, nothing threatens the films, and therefore, they can be brought directly to the pipe, fixing with adhesive tape. At the same time, a groove made of stainless steel (or made from the same film) must be installed in the waterproofing layer above the pipe to remove moisture that has fallen under the roof.

Important! When choosing a chimney with a heat-insulating layer, it should be taken into account that a number of factors affect the temperature of its outer surface at the point of exit to the roof: the height of the pipe, the type of heating equipment, the thickness of the thermal insulation layer, etc.

The output of a steel pipe through the eaves of an insulated roof has a certain advantage. Since there are no steam, hydro and heat insulating layers in the overhang design, there are thus no problems with the smoke channel wiring through the roofing "pie" with the continuity of all layers and a guarantee of fire safety.

It will also significantly simplify the task of bringing the pipe through a U-shaped cutout in the cornice overhang, which excludes the very presence of an junction with the roofing. True, in this case it will be necessary to provide for an additional drain in the cutout area.

However, it must be borne in mind that, being removed from the ridge, the chimney will turn out to be quite high and will experience serious wind loads. And therefore, to strengthen it, you will need a stretching system, for which you will also have to provide a sealed passage through the roof.

Attachment to roofing

Conclusion of a ceramic chimney to the roof

The main thing with its device is to ensure the removal of water from here, flowing down the walls of the head and along the slope of the roof, for which an apron is provided around the pipe. For chimneys of rectangular or square section, it is created using accessories for roofing. When ceramic roofs andcement-sand tiles plastic self-adhesive tapes (lead, aluminum) are used, which are glued with one edge to the pipe, and with the other - to the roof. To prevent water from leaking under the tape, its upper edge is closed with a metal bar of a curved profile, fixed with heat-resistant dowels and the joint is treated with roofing sealant.

On shingle roofs the apron is usually formed from a valley carpet or ordinary tiles laid with a call to the pipe, and on metal-tiled it is made from smooth sheets of the same material.

When making the junction on the side of the chimney that is higher along the slope, the apron must be brought under the roofing. Thus, the overlying roof element will cover it with an overlap, which will eliminate the possibility of leaks.

razuklonka

If the width of the rear wall of the chimney (that is, facing the ridge) is more than 80 cm, then behind the pipe it is necessary to arrange a ramp, or, in other words, a groove - a small pitched structure, which is a fracture of the roof, which will dilute water flows on the sides and will not give to accumulate here a mass of snow.

Creating a ramp is no easy task. After all, two short valleys appear in this zone, requiring the same high-quality performance as the “real” ones.

A wide chimney creates another difficulty: making it difficult to ventilate the under-roof space, it makes it necessary to install special ventilation elements on the roof - aerators, etc.

Elements of a steel modular chimney

Manufacturers of round chimneys (three-layer insulated structures in a stainless steel shell) produce ready-made elements that ensure the tightness of the junction of the pipe to the roof. These are the so-called passages consisting of a steel sole and an apron-cap fixed on it. In order to prevent their damage during temperature deformations of the pipe, the passages are rigidly fixed only to the roof, and a “skirt” is put on the joint of the cap with the pipe - a steel collar with an elastic heat-resistant gasket that does not allow water to penetrate under the apron.

The passage element built into the roof is sealed with pieces of heat-resistant plastic tape (based on lead or aluminum) or framed with a special lead detail, giving it a roof relief profile. Please note: the upper edge of the sole should be brought under the cover, and the bottom edge should overlap it.

Sometimes, in order to increase the tightness of the metal penetration, the steel sheet of the sole is mounted on top of the roof, bringing it directly under the ridge element. From the point of view of protection against leaks, the solution is reliable, but not aesthetically pleasing.