Thermal insulation of stoves: how to guarantee protection of the wall behind the stove

When using a stove or fireplace, a nearby wall will become heated to varying degrees. Of course, this can be unsafe if this point is not taken into account when planning the project. In this article we will talk about how to ensure a solution to this problem - safety when operating furnaces.

It is logical that the entire “thermal shock” from the stove during its operation is received by the nearby wall, which means that it can either prevent a fire or become its root cause. The safety of the building in this case will be determined by two conditions: 1. whether the required distance from the stove to the wall will be maintained; 2. Will the wall be protected with fireproof materials? Let's begin...

Where to install the stove

You can’t just put a stove in the middle of the steam room; it’s important to take into account the location of the air ducts, correctly calculate the distances from the walls, and think about protecting the walls of the bathhouse from heat.
If you look at the “Appendix to SNiP 41-01-2003”, you will find lines where it is clearly stated that if the walls of the bathhouse are not flammable, that is, they have a fire resistance limit of 60 minutes or more, then a metal stove is allowed to be installed at any distance, but it is better when there is more than 380 mm of free space between the steel stove and the wall. If you look at the “Appendix to SNiP 41-01-2003”, you can find lines where it is clearly stated that if the walls of the bathhouse are not flammable, then there is a fire resistance limit 60 minutes or more, then a metal stove is allowed to be installed at any distance, but it is better when there is more than 380 mm of free space between the steel stove and the wall.

It is quite difficult to find completely brick or concrete walls in a bathhouse without cladding; often the finishing is done with highly flammable wooden paneling.

It’s another matter if the wall material is wood. In this case, you should adhere to the following rules:

• When purchasing a factory stove, ask for instructions for it and carry out the installation strictly according to the manufacturer’s diagrams. This rule is stated in SNiP 41-01-2010, namely in paragraph 6.6.2.19 (Individual stove heating);
• there should be more than half a meter from the hot walls of the unit to the walls not protected by screens;
• the wall or partition through which the fuel channel is discharged must be made of non-combustible material from the floor itself to a mark of 25 centimeters above the combustion door;
• the thickness of the non-combustible wall through which the fuel channel is routed must be 12.5 cm;
• if the ceiling in the steam room is thermally insulated and protected with plaster over a metal mesh or similar, then the distance from the top of the metal stove to the ceiling should be more than 80 cm;
• in cases where the ceiling is not protected by fireproof materials, the distance from it to the stove should be more than 1.2 m;
• from the fire door to the opposite wall there should be more than 125 centimeters;
• Leave 3 cm between the wall and the front wall of the stove with an external firebox.

Fireproof distances from the stove to the walls

When choosing the best location for your own furnace, take into account the location of such elements as external heat exchangers, wall-mounted heaters, hot water tanks, and pipelines for remote tanks. These elements must be freely accessible for repair and maintenance.

The wall behind the stove! Option to protect a wooden house from accidental fire

The wall behind the stove (more precisely, its protection) is a very important issue of fire safety. This issue is especially relevant if the house is wooden. And for good reason! After all, a negligent attitude towards such a place as the “stove wall” can lead to disastrous consequences.

To neutralize the dangerous effects from the main heater in a building on walls located close to it, various methods and construction technologies are used. Starting from the use of protective mastics and impregnations that are used to treat the wooden surface, and ending with the arrangement of so-called “fire-retardant shields”.

In the first case, the wall near the stove retains its original appearance. Those. a wooden house remains that way internally. This option will be useful when you want to preserve the image of wood in the interior. But there is one significant drawback. Over time, wood shrinks, becomes deformed and even cracks. And this leads to the formation of “weak points”. And to neutralize the possible risk of fire, the wall behind the stove requires periodic treatment of the wooden surface with protective agents.

The second option is more durable and more reliable. He suggests that insulation of the walls from the furnace is carried out by installing a fireproof shield. Let's look at this option in more detail using an example.

The easiest way is to install a sheet of metal to the wall of a wooden house from the stove side. Yes - simple and fast. But this approach will clearly harm the interior of the house! In this case, decorative finishing of the wall behind the stove will be difficult. And, besides, the efficiency of such a design will not be the highest.

There are many options for arranging a shield. And here is one of them. The wall near the stove is lined with non-flammable thermal insulation to reduce the impact of hot air on the wood, and the top is covered with non-flammable sheet material to prevent the surface from igniting when a coal or spark hits it. It usually consists of a sheet of metal (not the best option), fireproof gypsum plasterboard, LSU, etc.

So, we've sorted out the materials. Next, let's look at an example of how a wall near a stove is insulated from harmful influences.

First of all, the wall behind the stove is prepared for work. We remove sawdust and other debris that is on it. This, of course, is not necessary, but it will not be superfluous.

Next, a metal profile and self-tapping screws are used. With their help, we equip the frame of the future “thermal shield”.

When the frame is ready, we install thermal insulation slabs of stone wool into it...

... and sew it up with LSU sheets.

This is how the wall is insulated from the furnace by installing a “fireproof shield”. This design also meets fire safety requirements and is suitable for further decorative finishing. Most often, ceramic tiles are used for this. As a result, the wall near the stove will be fireproof and beautiful (after applying a decorative coating).

Protective screens near (around) the stove

Protective screens are insulation panels that cover the side surfaces of the furnace and reduce the intensity of thermal radiation. Screens can be metal or brick. As a rule, they are used for metal furnaces.

Method #1 - metal screens

The most common protective screens are factory-made steel or cast iron sheets. They are installed around the stove, at a distance of 1-5 cm from the walls of the firebox. Depending on the need to insulate one side or another of the furnace, you can purchase side or front (front) screens. Many metal furnaces are initially manufactured with protective screens in the form of a protective casing.

Protective screens make it possible to reduce the temperature of external metal surfaces to 80-100°C and, accordingly, reduce the fireproof distance to 50 cm. The total distance from the firebox to the wall (including a gap of 1-5 cm) will be 51-55 cm.

Installing protective screens is not difficult. Thanks to the presence of legs, metal panels are easily bolted to the floor.

Method #2 - brick screens

A brick screen can cover all the side surfaces of a metal furnace, representing its outer cladding. Then the stove will be in a casing made of brickwork. In another case, a brick screen is a wall separating the stove and the flammable surface.

To lay the protective screen, solid fireclay bricks are used. The binder is cement or clay mortar. It is recommended to use half a brick (thickness 120 mm). But, if there is a lack of material, it is possible to make a wall of a quarter of a brick (60 mm thick), although in this case the thermal insulation properties of the screen will be reduced by half.

Small openings (sometimes with fire doors) are left at the bottom of the shield for air convection between the brick wall and the stove.

The brick walls of the screen must end at least 20 cm above the top surface of the oven. Sometimes the masonry goes all the way to the ceiling.

The brick screen is not installed flush against the walls of the stove, the optimal distance is 5-15 cm. The acceptable distance from the brickwork to the flammable wall is 5-15 cm. Thus, the use of a brick screen allows you to reduce the distance from the stove to the wooden wall to 22-42 cm (stove - ventilation gap 5-15 cm - brick 12 cm - ventilation gap 5-15 cm - wall).

Products used

The following materials can be used for chimney insulation:

• mineral wool;
• glass wool;
• brick;
• slag slabs or heat-resistant cement mortar.

The insulation of a chimney depends on the material from which it is made. If the pipe is steel, then construction wool is used. The design consists of 2 parts (length does not exceed 1.5 m), which simplifies compaction of the insulating material. The size of the casing should be 12 cm larger than the diameter of the pipe.

The first part of the structure is first put on. Then the insulation is applied evenly. The second part of the chimney is installed. The building is insulated. The pipe is installed with a slight slope. The resulting gap is covered with cement mortar.

A steel chimney consists of 2 pipes of different sizes. A protective casing is placed on the smaller pipe (chimney). A thermal insulation layer is laid between the pipes. A pipe with a smaller diameter is placed in a structure with a larger diameter. The gap formed between the pipes is filled with construction wool.

A brick chimney is insulated using the following technology:

• applying the base;
• installation of reinforced mesh;
• sealing cavities and cracks with a solution;
• applying plaster in several layers (their thickness should not exceed 5-7 cm);
• complete thermal insulation;
• mineral wool is cut taking into account the size of the chimney;
• fixing the heat insulator with metal tape or wire;
• lining the pipe with ceramic or asbestos slabs;
• plastering the surface.

This method of thermal insulation allows:

• reduce heat loss by 2 times;
• seal the chimney;
• prevent the formation of condensation and destruction of the chimney;
• improve quality and safety.

Furnace insulation is a necessary procedure for a high-temperature furnace used to heat a home.

Thermal insulation work can be done with your own hands, following the recommendations described above.

Application of protective screens

Screens are shields made of brick or metal that protect walls from intense thermal radiation. Similar protection is used when installing metal stoves.

1. Metal screens are made from steel or cast iron sheets, these

casings surround the heat source with a distance of 3-5cm.

Advice! When purchasing a metal sauna stove, you should give preference to a model equipped with a metal casing. Its cost is not much higher, but the issues of wall insulation are eliminated.

Additional frontal or front shielding, which is located on the walls depending on the location of the stove, will not hurt. The protection guarantees the wood from overheating, reducing the temperature by 100 degrees or more, and provides the opportunity to save space in the steam room. A stove protected by a casing can be installed at a distance of 50-55cm from the wall.

Installation of screens is simple. The casing, equipped with legs, is secured to the floor by side or front screens - with galvanized nails or self-tapping screws.

1. Brick screens are masonry used to cover the stove with

on all sides, the same casing, only made of brick. Another method is to lay half a brick between the firebox and a wall made of solid fireclay bricks laid on a solution of clay and cement. The width of the wall should be 120mm, although there is an opinion that it is permissible to put 60mm in a quarter of a brick, but it should be remembered that in this case the thermal insulation value is reduced by exactly half. It is recommended to raise the height of the masonry 20-30 cm above the surface of the firebox, but if you raise it to the ceiling, it will not be worse.

The screen should be placed at a distance of 10-15cm from the wall, 5-15cm from the stove, that is, the space saving is 30-40cm

Important! Functional openings for heat exchange should be made at the bottom of the masonry. Protective screens are effective, they reduce the temperature to a level acceptable when using high-temperature fuel units

The same function is performed by wall cladding made of non-combustible materials.

Protective screens are effective; they reduce the temperature to a level acceptable when using high-temperature fuel units. The same function is performed by wall cladding made of non-combustible materials.

When is this required?

There are times when there is no need to protect walls. If the stove is located at a safe distance from the wall from a fire safety point of view, the installation of protective screens and other measures can be neglected. The distance from the walls that is required to reduce the heat from the source varies:

• A stove laid in a quarter of a brick should be located no closer than 35-40 cm from the wall;
• A metal stove without lining should be placed a meter away and no closer;
• A metal one with a lined furnace can be installed 70-75cm from the wall.

However, not every steam room has the opportunity to fulfill these requirements, due to the small area. The layout of steam rooms with an area of ​​6-8 m² can hardly accommodate the necessary set of items for the steaming procedure. Therefore, the need to insulate walls with special sheathing is relevant.

Protective screens near or around the oven

Such a system will need to be implemented when installing a potbelly stove in the corner of the room. You can mount or lay out several screens from brick, installed at a short distance from each other. In this case:

• The first screen protects a person from touching the iron stove and getting burned. It is usually made of refractory or fireclay bricks;
• To protect walls made of flammable material, a second layer of protection is provided. It can be made of brick or covered with a barrier made of sheet steel with a mirror-like front surface. In this case, heat waves will be reflected from the mirror and spread faster throughout the room;
• if the foundation is insufficient in size or it is impossible to manufacture it, it will be necessary to lay a protective screen made of durable fire-resistant material on the wooden floor. This can be a sheet of steel or a decorative layer of heat-resistant clinker tiles or porcelain stoneware. The surface will first have to be covered with a layer of thermal insulation.

Installation of metal screens

This is the easiest way to make surface protection. It is better to use sheets with a polished front surface. Before fastening, the wall surface at the required level along the height of the screen is covered with a layer of thermal insulation. In this way, we protect the surface of the walls from the effects of heat.

You can lay a layer of thermal insulation or fasten the metal with self-tapping screws with inserted ceramic spacers. But it is better to attach the screen to strips or a metal profile treated with a layer of protection. In this option, the air gap will not allow heat to pass freely to the walls, and reliable insulation of the stove from the wooden wall is ensured.

A special gap is made at the bottom of the wall for the passage of cold air, ventilation of the wall and screen. When arranging a wall with a layer of thermal insulation, a number of longitudinal guides are installed on the surface. The space between them is filled with a layer of mineral wool or other material. Then sheets of metal are installed and screwed to the sheathing with self-tapping screws.

In this design, there is no need to leave a gap at the bottom. The air will not be able to pass through calmly, but the wall will be reliably protected from high temperatures. To protect the floor of the house, a slab made of non-flammable durable material can be used.

Brick screens

This protection option is usually installed near the stove. Thus, you can protect not only the wall, but also the person from burns. By installing a brick wall, you can reduce the distance from the stove to the wall. For laying, it is better to use ceramic or fire-resistant bricks.

The work is carried out in several stages:

• you will need to make a small foundation or remove boards from the floor along the marking lines for laying the screen and, by drilling holes in the concrete of the base of the building, insert metal rods to fasten the bottom of the wall and the foundation;
• Having leveled the floor surface, lay out a layer of mortar and lay the first row of bricks; you need to place the bricks in the same plane without distortions. This determines how level your entire wall will be. Do not forget to make small grooves for ventilation; for this you can move several bricks of the bottom row.
• checking the level and pulling the twine for laying each subsequent row, all bricks are laid on a mortar of clay and sand. Having raised the wall to the required height, the top is sealed with a layer of mortar or covered with a board. This way you can make a shelf for decorative ornaments and all sorts of little things.

The brick is laid no higher than the top of the furnace at a distance of at least 40-100 mm from it.

Using both types of protective screens, you can reduce the distance from the oven to 500 mm.

Examples of installation of protective brick screens in the photo:

SNiP standards for the location of the furnace from the walls

The standards for these requirements are specified in 2 main documents:

• SNiP III-G.11-62;
• SNiP 2.04.05-91.

Based on these regulatory documents, each owner of a solid fuel stove is required to maintain minimum clearances from the wall and ceiling, taking into account the surface material:

By maintaining the minimum dimensions, or better yet, making gaps with a small margin, every owner of a wooden house can be sure that its walls and ceiling are protected from high temperatures.

One of the main methods of protection is the manufacture of devices installed to protect the front and side surfaces near the stove itself.

Types and rules for the manufacture of fireproof cladding

Fire walls can be created using sheathing made from non-combustible materials. Today, 2 variants of such designs are used:

• reflective coverings;
• sheathing with cladding.

To produce reflective protection, thermal insulation material is attached to the wooden surface of the walls, which is covered with a steel sheet. A few years ago, galvanized and stainless steel sheets were used equally widely. However, studies have shown that when heated, galvanized steel can release harmful substances, so it is preferable to build fire walls from stainless steel.

In order for the reflective effect to be as intense as possible, the surface of the sheet must be well polished (almost to a mirror finish).

Protective screen reflector made of stainless steel

The following can be used as a heat insulator fixed under steel:

• basalt wool, which has good thermal insulation characteristics and absolute environmental safety;
• basalt cardboard, the base of which includes basalt fiber;
• asbestos cardboard, characterized by good fire-resistant qualities;
• mineralite, made specifically for shielding surfaces.

Fire walls sheathed with steel sheets are quite simple to install. The main thing is to remember what each layer of cladding should consist of:

• wall;
• a gap of 2-3 cm, providing ventilation between the wooden surface and the heat insulator;
• thermal insulation material (at least 1-2 cm thick);
• sheet of steel.

The distance from the furnace body to the steel sheet must be at least 38 cm. It is recommended to use ceramic bushings for fastening materials. They are not exposed to heat and do not deform, ensuring the safety of the ventilation gap between the heat insulator and the wood.

Construction of a fire-resistant wall

When the distance between the heater and the wall is less than 38 cm, it is necessary to use a double layer of fire-resistant material. The best choice would be mineralite. It is secured with ceramic bushings with a gap of 2-3 cm from the wooden wall and covered with stainless steel.

Protective non-combustible wall coverings

If there is no need to carry out work to protect walls using screens, in this case, you will still need to reliably protect the surfaces from exposure to high temperatures.

You can use classic mineral wool or use mineralite slabs. We get a reduction in the distance from the wall to the stove in the house, without the risk of fire and deformation of building materials.

Minerite

Installation of reflective trim

This is one of the main methods of protecting surfaces from high temperatures. To do this, you can use a sheet of thin cold-rolled metal with its glossy surface or buy more expensive stainless steel sheets with a mirrored face. This heat-reflecting protection allows you to quickly heat the room without wasting firewood and reliably protects the walls and ceiling from deformation.

First, the sheathing strips are secured. The bars should be selected taking into account the thickness of the insulating material. A thermal insulation layer is embedded in the spaces between the sheathing parts. On top of it, sheets of reflective sheathing are attached to wood or metal screws (this depends on the material of the bars).

Using this method of protection, you can reduce the distance from the stove to the wall to 380 mm.

Protecting walls from the heat of the stove can be used as decorative decoration for premises.

Examples:

Photo 1

Photo 2

Installation of sheathing with cladding

This method will require increased costs for the purchase of materials, but will also make your home cozy and beautiful. Porcelain stoneware or expensive tiles can be used as cladding, it all depends on the capabilities of the owner of the house.

Work on the protection and decorative finishing of walls is carried out in several stages, the result is a kind of cake:

• a ventilation gap is made on top of the wall, 20-30 mm thick;
• then a layer of thermal insulation is laid and fire-resistant drywall is attached on top of it;
• A layer of decorative finishing is laid on fire-resistant glue or mastic using beacons to ensure an equal gap between the rows. It is important not to use large tiles. Such parts are more susceptible to deformation, unlike small tiles.

Using this method, you can reliably isolate the stove from the wall and make a gap of 150 mm between them.

Example

Step-by-step instruction

Thermal insulation work is carried out taking into account certain rules and safety standards. It is first recommended to decide on the method of insulating the stove. The following elements are thermally insulated in the furnace structure:

The first structure is insulated in the following cases:

• reduction of heat consumption - thermal insulation work is carried out when the fireplace or stove is not designed correctly, when all the heat comes out through the chimney (due to excessive draft or the use of materials with high heat transfer);
• insulation retains heat;
• elimination of condensate: if the pipe is not insulated, condensate collects in it, it destroys the pipe masonry or welded coating joints.

Experts recommend insulating the surface of the stove located close to the walls of the house. Otherwise, cracking of the brick will occur due to temperature fluctuations. Thermal insulation between the wall and the stove is carried out using the following materials:

• asbestos slabs;
• thermofoil (as a heat reflector).

The method under consideration is used if the space between the stove and the wall exceeds 5 mm. If the distance is small, then asbestos cannot be used (due to the composition of the material).

It is possible to carry out thermal insulation work using the following technology:

• strengthening the wall using metal sheet hangers;
• installation of slabs of ceramic or asbestos insulating material;
• filling gaps and seams with mineral wool;
• winding the pipe with an external reflector (foil).

Since mineral wool does not tolerate condensation, a special material should be used to insulate this seal. A similar technology is used for furnace thermal insulation. At the same time, the wall does not heat up or heat up.

Other methods of insulating walls from the furnace

Thermal insulation of a stove from a wooden wall can be carried out using modern materials, with which it is possible to apply a sufficient layer of thermal insulation not only to the walls, but also to apply it to the stove:

• Sheets of environmentally friendly basalt wool with an outer layer of foil. This material can withstand temperatures of at least 7000. This material can be used to insulate fireplaces and chimneys;
• Gypsum fiber sheets. They are produced by pressing natural gypsum material and cellulose. This material does not require additional surface treatment with a layer of waterproofing. Can be used for thermal insulation of the combustion chamber and the body of the potbelly stove from the outside;
• The use of calcium silicate allows you to reliably insulate the firebox and internal surfaces of fireplaces. But the material is expensive, so it is not in high demand.

  
  Calcium silicate panels

Conclusion

Thermal insulation materials for stoves are an important component of the stove itself, without which it will not be possible to properly arrange the work.

Also, it is worth adding that it is very important to choose the right material, install it firmly and not overpay a lot of money for it. Fortunately, there are now a huge number of materials and by studying them, you can understand for yourself which one will suit your stove or wall

Fireproof decorative panels for stoves can not only protect you, but also complement your interior. Experts say that choosing insulating material should be like choosing wallpaper. Sheets, panels or slabs must fit correctly into the overall picture of the room, especially if we are talking about a stove inside the house.

Heat-resistant insulation for furnaces is not a luxury, it is a necessity. You could even say that this is an important element of the stove, which you cannot do without. When equipping your stove, do not forget to immediately make a list of the necessary materials for thermal insulation of the surface around the stove.

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