The clay on the stove is cracking, what should I do? How to plaster a brick oven

One of the features of brick kilns is the appearance of cracks during operation. This may be caused by objective reasons, or perhaps by defects in the stove or errors in the masonry. In any case, it is advisable to seal them. Especially those that are located near wooden parts. This is basically what the current repair of brick kilns consists of.

Quite often cracks in the seams occur in brick kilns. Most often they appear at the junction with the casting: different temperature expansion affects it. Cracks can also occur due to local overheating, as well as due to errors in masonry. If the solution does not pour out, there is no particular cause for concern, but the cracks in the oven need to be sealed.

Repair of small cracks - up to 5 mm - can be done using any of (clay + sand; clay + sand + a little cement). Ready-made formulations diluted according to the manufacturer’s recommendations are also used. If you know what kind of solution the stove was placed on, it is better to use the same one; if not, any will do. Only the color difference will be visible.

It is better to cover deeper cracks in the furnace masonry with a solution containing crushed fireclay and aluminous cement. If such cement is not available, you can use Portland cement, but you will need a finely ground additive for laying stoves. The presence of ground fireclay reinforces the solution, preventing cracks from appearing again.

How to cover up the cracks in the stove masonry? The operating procedure is as follows:

heat the oven a little,
widen the cracks
clean them from dust,
moistened with water,
cover with the selected solution.

Actually, that's all. We wait for the solution to dry, then you can heat the stove again, but not to the full load, but about half. Then you can heat it as usual.

Wider cracks and the mortar spills out....

In addition to covering the cracks in a brick oven with mortar, you can fill them with soaked asbestos cord, and cover everything on top with mortar. Just be careful when working: asbestos in a dusty state is harmful. Better work wearing a mask.

Brick kiln firebox repair

If the firebox is made of red rather than fireclay brick, sooner or later the brick begins to crumble. It sometimes falls off in quite large plates. There is no point in covering it up or reinforcing it with something. The temperatures will cause everything to fall apart.

It is possible to stop the destruction of bricks in the firebox of a brick kiln only by reducing the impact of temperatures. To do this, it is necessary to make additional lining - install barrier walls that will take on the main thermal load. That is, the firebox (entirely or just the collapsing walls) is sheathed/covered from the inside with some kind of material. It could be:

The last two materials are rarely used, but they can be used if the volume of the firebox is small and you don’t want to reduce it with fireclay. The only thing is that you will need to come up with a fastening system, since in each case it is different. And keep in mind that the slabs should also not be placed close to the walls of the firebox, but with a small gap.

Such repairs to the lining of a brick kiln make it possible to avoid, or at least postpone for some time, more serious work, which sometimes includes a complete overhaul of the kiln, replacing damaged elements, and sometimes changing the design.

What to do if there are cracks around the casting

Due to the large difference in the magnitude of the temperature expansion of metal and brick, cracks often form at the junction. To avoid them, during installation, recesses are made in the brick, which allow the metal to expand when heated without destroying the masonry (the recesses are 3-5 mm larger than the casting shelf). To soften the impact, the casting is wrapped in thermal insulation material. Previously, they used asbestos cord or cardboard, but now they often use mineral wool cardboard cut into strips or a special sealing cord (asbestos is harmful). When choosing cardboard, pay attention that it must withstand temperatures of 800°C and above.

If cracks do appear, they are repaired as described above - using a solution with the addition of fireclay. But if the damage is such that the door wobbles, as do the bricks above it, if the design allows, it is better to disassemble and reattach everything, tighten the fastening wire and re-wrap the casting with heat-insulating material.

Cracks around the casting - around the doors, near the stove - require repair

To prevent the cast iron stove from cracking

Another common problem with using brick stoves, not purely bath stoves, but heating and cooking stoves, is cracks in the cast iron stove. They are not terrible if the stove is made correctly, but if there are errors in the masonry or design, smoke and carbon monoxide can leak through the crack, which is many times worse.

In principle, a well-cast slab made of high-quality cast iron should not crack, but the trouble is that such things are very rare. However, trouble can be helped. When firing for the first time, you need to slowly heat the stove, avoiding local overheating, and cool it down just as slowly. This can be done by laying bricks on the surface of the cast iron or pouring a good layer of sand. Remove the brick and sand after the stove and stove have cooled completely. These materials distribute heat without allowing large temperature imbalances, and therefore cracks. Also, a uniformly loaded hob will sit smoothly, without distortions, which can also cause stress and cracks.

How to plaster a stove so that it does not crack during everyday use? This question arises for those home owners who have just acquired this heating device, and in cases when the time has come to repair a stove that was built a long time ago.

It should be noted that cracking most often occurs when there are violations in the technology of the plastering process or in the preparation of the surface for applying the finish, as well as due to improper preparation of the solution.

To plaster the brick walls of the kiln, traditional sand-clay mortars and professionally prepared plaster mixtures are used, which can be bought today at any construction or specialized store.

But whatever type of plaster is chosen, it must meet certain requirements, such as heat resistance, high adhesion and an adequate response to the expansion of the wall material when heated.

Why plaster the stove at all?

In what cases and why are stoves plastered? The answer to this question is no less important than the first, since, having learned it, you can understand whether this process is worth carrying out at all, or whether you can leave the stove without finishing, or decorate its walls with ceramic or fireclay tiles.

Reasons that require finishing walls with plaster include:

If the stove is old and was previously plastered, but for some reason the finishing cracked and began to fall off, and sloppy masonry was discovered underneath.
If the stove is old and there is a danger of cracking of the masonry mortar in the seams and the penetration of carbon monoxide into the room.
If there is a need to transform this structure, giving it neatness and aesthetics, for example, when updating the entire interior and changing its design style.
Over time, various insects can take up residence in the seams between rows of bricks, especially in cases where the masonry was made using natural materials. Timely processing and plastering will help prevent their occurrence.
If the stove has just been erected, but the masonry is done sloppily, without jointing, and the structure does not look aesthetically pleasing, plaster will help correct this situation.

The advantage of plaster over other finishing materials:

It should be noted that plastering the stove is the most affordable and easiest way to tidy up the surface of the stove.
By choosing plaster for wall decoration, you can save a lot, since the price of ceramic tiles or stove tiles is several orders of magnitude higher than the price of plaster mixture.
Plastering can be applied to any of the existing types of stoves, both for the restoration of an old stove and for finishing a newly built one.
Plaster increases the thickness of the wall, which increases the heat capacity of the building and leads to fuel savings, since the stove takes longer to cool down.
Plaster increases the level of fire safety and reduces the possibility of carbon monoxide entering the room.
The plastered surface can be covered with water-based paint, whitewash or decorative plasters.

Tools for getting the job done

The quality of plaster application and its ideal distribution on the surface of the furnace walls directly affects the adhesion of materials and longevity operation. In order for the plastering process to be easy and bring the expected result, it must be carried out with high-quality tools, which include:

Spatulas - from medium for taking the solution from the container, to wide, used for applying it to the wall.
Plaster hammer used for driving plaster nails.
Trowel (trowel) for applying and distributing mortar on stove walls.
A cam hammer used to work with chisels, trojans and gears.
Standard scissors for cutting fiberglass mesh. If the walls are covered with chain-link mesh, then metal scissors will also be required.
Grater and grater. These tools are used to level and smooth plastered surfaces.
The trowel is used to bring the surface to perfect smoothness.
Chisel. Using this tool, notches are made on the surface of the furnace walls for better adhesion of materials.
Brushes of different sizes for applying primer compositions, and when using some techniques - both the plaster itself and to give it a textured surface, if provided.
Brush with metal bristles - for cleaning surfaces and seams when removing old plaster.
Construction level for checking the vertical and horizontal planes.
A plumb line is used to control the evenness of walls and applied plaster.
The rule helps to align the plaster applied to the walls according to the beacons installed on them.

Types of plaster solutions

As you know, the oven is exposed to constant temperature changes, so the plaster layer must be resistant to this phenomenon. When making up the solution yourself and selecting the proportions of materials, you must take this into account.

The most important point is the composition of the plaster mortar

Plaster mixtures can be simple or complex:

Simple are compounds consisting of two ingredients - clay and sand.
Complex solutions are those that contain more than two components.

Before making the mixture, some of the materials need to be prepared by cleaning them from various impurities:

The sand must be sifted through a fine sieve.
The clay is also rubbed through a fine metal mesh, turning it into powder and freeing it from plant roots and small stones.

The clay for making the plaster mixture is chosen to be quite fatty, since this quality will directly affect the adhesion of the plaster and the wall. If excessive fat content of the clay is noticeable, a little more sand can be added to the solution.

Before mixing the solution, the clay is soaked by mixing with water. Next, it is left for several hours. If during this time it has absorbed all the water, then more liquid is added, and so on until the water covers the clay from above by 100 ÷ 150 mm. After this, the mixture is mixed - it should have the consistency of thick sour cream and have good plasticity.

Prices for heat-resistant plaster

plaster for stoves and fireplaces

Video: tips for properly soaking clay for mortar

Asbestos, which is added to the solution, plays the role of a reinforcing component. Instead of asbestos, hemp, finely chopped straw or shredded fiberglass (microfiber) can be used.

It should be noted that for plastering compositions it is better to choose natural, environmentally friendly materials that, when heated, will not emit harmful fumes that are unsafe for the health of the residents of the house.

Some craftsmen add salt to the solution and explain this by saying that it makes the solution stronger. However, this is not quite true. Salt does not strengthen the clay, but it increases its hygroscopicity, which makes it more plastic, preventing it from drying out, so the plaster cracks less. In addition, salt plaster does not harbor various insects, which is also very important for a private home.

The table below shows several recipes for plaster mortars for stoves.

Composition Number	Clay	Sand	Fluffed asbestos	Lime	Cement	Gypsum
1	1	2	0.1	-	-	-
2	1	2	0.1	1	-	-
3	1	2	0.1	-	1	-
4	1	1	0.2	2	-	1
5	1	1	0.2	2	-	-
6	-	1	0.1	2	-	1

Separately, it is necessary to say about such a material as gypsum, which is one of the components of some plaster solutions. For example, in mixture No. 4, it is used instead of cement as a fastening agent. Gypsum hardens very quickly, it sets almost immediately after application to the wall, and after 10 ÷ 15 minutes the plaster layer using it will already harden.

This building material is often used together with lime, as it gives strength to the solution and promotes rapid drying. But, having chosen a solution with the addition of gypsum, you need to take into account its properties and prepare small portions of the mixture, otherwise it will harden and be unsuitable for work. It is definitely not possible to extend its “life” even for a short time by diluting it with water.

We plaster the stove with our own hands

Preparatory work

Plastering will not be of high quality if the surface of the furnace walls is not well prepared for applying the finishing material. Therefore, the first step is preparatory work that will create good conditions for the adhesion of the plaster mortar.

If an old stove or fireplace is being repaired, then its surface must be freed from the plaster on it, knocking it down manually using a chisel and hammer. After the walls are freed from the old layer, they are well cleaned of dust - this process is carried out with an iron and ordinary brush.
The fresh masonry of the stove must also be cleaned, since the remains of masonry material may linger on the bricks, which will reduce adhesion, which will lead to the plaster falling away from the wall.
Next comes the deepening of the seams, and this is carried out both for a new stove and for a restored one. Dry mortar from the joints is selected to 5 ÷ 10 mm. Then the seams are well cleaned of dust.
After cleaning, the walls are primed well, and it is necessary to cover the buried seams with a thin brush.

Sometimes it is necessary to apply several layers of plaster - this need arises if the walls of the furnace are very uneven. This method of plastering requires additional reinforcement of the surface with a metal or fiberglass mesh with cells of 15 ÷ 20 mm. Reinforcement will secure the plaster well on the walls and make it less vulnerable to temperature changes. In addition, a thicker layer will increase the heat capacity of the oven. The metal mesh is attached to the surface using nails with wide heads that driven into the seams between bricks.

The fiberglass mesh is embedded in oncarried the mixture is applied to the wall, or the solution is placed on top of the mesh, leveling it. Fiberglass is mainly used if the surface is fairly smooth.

To maintain or restore the evenness of the corners of the stove, steel or perforated aluminum corners are mounted on them with an adhesive mixture.

In order to achieve evenness of the wall with large differences, beacons made of metal profiles are placed on top of the reinforcing mesh, fixed to the surface with a gypsum mixture that dries quickly, which practically does not slow down the work. If time is of the essence, then the beacons can be placed on a clay solution. But this method is possible if the mesh is adjacent to the wall.

The walls of the stove can be leveled to perfect smoothness for whitewashing or painting, or the surface can be left smooth, but rough, to be covered with decorative relief plaster. It should be noted that it is recommended to apply a not too thick preparatory finishing layer under laying ceramic tiles or decorative plaster.

There are various ready-made compositions or additives that help imitate natural stone of different types. In this case, the surface of the furnace, with the correct composition of the solution, will be impossible to distinguish from natural material.

The table shows the recipe for preparing decorative plaster solutions.

Component sucking of decorative plasters imitating the texture of natural stone, in parts by volume
Material	White marble	Yellow marble	Red marble	Gray granite	Labradorite
Portland cement M400	1	1	1	1	1
Lime dough	0.2	0.15	0.1	0.1	-
Marble flour	0.1	0.05	0.1	0.1	-
Marble chips up to 6 mm in size	3	3	3	3	3
Mica (based on cement volume)	0.1	0.1	0.1	0.1	0.1
Paint (based on cement volume), %	-	Ocher 3 ÷ 5	Iron minium 5÷10	Manganese peroxide 1÷5	Manganese peroxide 6÷8

Preparation of plaster mixture

A solution composed in the correct proportion and well mixed is one of the factors on which high-quality plastering of the stove depends. To mix the mixture you will need a drill and a mixer attachment.

Before you start cooking, you need to consider some points:

Soaked clay, if it is used in a solution, must swell for at least two to three days. If, after standing for this time, it continues to absorb water, then it is not ready for kneading and you should add more water to it and leave it to swell for a while.
The sand added to the solution must not only be sifted, but also dried - this will help in maintaining the correct proportions when preparing the mixture.
Lime will be a good plasticizer for the solution - its viscosity will make the mixture more adhesive. In addition, it will help the solution to set quickly enough, which will shorten the work period. In principle, a small amount of it is recommended to be added to mixtures consisting of any ingredients.
The most suitable grade of cement is M400. It begins to harden 17 ÷ 20 minutes after mixing, sets in 3.5 ÷ 4 hours, and its final hardening and strength gain occurs after two ÷ three days.

If you purchase a ready-made dry mixture, it is easy to prepare:

Water is poured into a clean container of suitable size.
Then the powder is poured into the container, the proportions of which in relation to water are indicated on the packaging.
Using a mixer, the solution is mixed until a homogeneous mass is formed without lumps or dry inclusions.
The solution is kept for 7 ÷ 10 minutes, then mixed again, and after that it is ready for use.

If the solution for plastering is prepared independently, using traditional materials, then the process is carried out as follows:

The required amount of clay mass is laid out in the container. Dry sand, slaked lime and cement are added to it in accordance with the specified proportions.
The mixture is also mixed with a mixer until smooth. If necessary, a small amount of water is added to the solution during the mixing process.

This solution is used immediately, since the cement and lime set quickly enough.

Plastering process

As mentioned above, the plastering process can take place in different ways, some of which will be discussed below.

First way

This method is used if there are large distortions on the surface, and it requires radical leveling by applying a layer with a thickness of 50 to 80 mm.

In this option, the first step is to attach the leveling beacons. They are set to the building level, achieving perfect evenness.

After this, the oven is heated until warm.
Next, the entire surface of the oven is wetted with water using a wide brush or roller. Water will drive particles of dust and dry mortar into the seams.
After this, the walls are primed. The primer layer must dry, creating a layer that will promote adhesion of the surface and the applied materials.

Sketch of the solution, or “spray”

Next, by “spraying” (sketching), the first plaster layer is applied, which should not be thicker than 4 ÷ 5 mm. The solution for this layer should have the consistency of medium-liquid sour cream. The mixture is applied with accentuated movements, since the solution must get into the seams between the masonry rows. After completing the sketch, the solution is allowed to dry thoroughly.
After it dries, the next layer is applied, which should protrude above the installed beacons by 8 ÷ 10 mm. The solution is applied from the bottom of the wall, approximately 400 ÷ 500 mm, and is immediately leveled using the rule that follows the beacons. Next, the solution is poured onto the next area and leveled again, and so on, until the entire surface is covered with a leveling plaster layer.

While the mixture is still wet, carefully rub it with grout, sanding the surface.

Stove-makers have one secret that promotes uniform drying of the plaster layer, which reduces the risk of cracks appearing on its surface. The entire oven, after applying the mortar and sanding, is covered with damp burlap. If it dries quickly, it is moistened one or two more times.

When the surface has dried, the matting is removed, and if cracks are found, they are immediately rubbed and smoothed with a smoothing iron with a rubber surface.

The third layer, the “covering”, is a smoothing layer, so the solution for it is made quite liquid and applied with a thickness of only 1.5 ÷ 2 mm. This layer is applied if the surface of the oven is to be covered with paint or whitewash.
Difficulty always arises when drawing out corners, even if they are reinforced with metal corners. The easiest way to apply the solution evenly and level it well is to use an angled spatula.

Prices for corner spatulas

corner spatula

To create a corner, some craftsmen use a wooden strip on one side of it, and after the applied solution has dried, they move the strip to the other side of the corner and apply the mixture to the one where the guide was installed earlier.

It is recommended to round the very edge of the corner, which can be achieved by using a corner spatula. This must be done, first of all, for the safety of small children living in the house. Also, a rounded corner is less susceptible to chipping, for example, during repairs and moving furniture.

Second way

When using this method of putting the oven in order, a metal mesh is used, which reinforces the surface of the oven and sets the thickness of the plaster coating.

Use a metal mesh to level the surface, moving it away from the wall in the right places at a distance of up to 25 mm. For rigidity, a wire is placed under it, which can be hooked onto the mesh itself or metal slats.

In this method, the plaster mixture is also applied in several layers until the mesh underneath is completely covered.

Finishing using such reinforcement is more durable and securely fixed to the surface.

The first layer is also applied using the “spray” method - the solution must pass through the mesh and adhere well to the wall. Having sprayed this surface, the walls are left to dry. After they dry, the mesh will become motionless, and it will be easy to apply subsequent, leveling layers of the solution over it.
After leveling and drying the top, last layer, the resulting cracks are covered and rubbed.
The next stage is the installation of the decorative coating.

Third way

The third method of plastering is used if the walls of the furnace are quite smooth and they only need to be “refreshed” a little.

The solution for this method is applied in one or two layers with a thickness of no more than 2 ÷ 3 mm.

The wall is also prepared and primed.
Then, if necessary, thin metal guide rails, which will help you navigate the thickness of the layer. Slats may not be used if the surface is flat and there is no need for them.
With this finishing method, it is best to use a solution with the addition of fireclay clay and crushed asbestos, which will act as a reinforcing component.
The mixture is applied starting from the bottom of the oven using a wide spatula, and immediately leveled with a rule along the metal slats. If beacons are not used, then the solution is smoothed, focusing only on the evenness of the surface.
In this case, the corners are also drawn out using a corner spatula.
When the walls of the oven are completely covered with mortar, they are carefully smoothed out with grout without pressing.

It is good to lay ceramic or fireclay tiles on this finish, as well as apply decorative relief plaster.

Decorative design of the stove

Decorative finishing of the stove can be done to suit every taste. If the plaster turns out smooth, then bake can be covered with whitewash - this method can be called traditional, since it has been used for a long time. Whitewash was often painted with water-based paints, which gave the room originality and emphasized national traditions. Most often, ornaments were chosen that were characteristic of the area where the building was located.

Today, with the advent of new technologies and materials, the stove is often decorated with plasters that can create patterns on the surface that imitate one of the types of stone or a uniform relief structure.

There are other elements of three-dimensional drawings - in this case everything will depend on the imagination of the master. To create them, improvised objects are often used, for example, plastic film, brush, broom, mesh for cleaning dishes and other materials or accessories.

If you have a predisposition to creativity, you can use decorative plaster to create relief compositions that protrude beyond the walls of the stove even by 7 ÷ 10 mm, and then cover them with coloring compounds. Paints are applied over damp decorative plaster - then they are well absorbed into its surface and become more durable. After the entire surface has dried, painting can be done one more time.

In addition to decorative plaster, the stove is often decorated with terracotta or ceramic tiles. The availability of corner finishing elements on sale greatly simplifies its installation and makes it possible to make corners and all surfaces neat and aesthetically pleasing. The tiles are mounted on a special cement-based adhesive composition, which has the ability to withstand the effects of temperature changes.

Video: plastering a stove followed by finishing with terracotta tiles

What do you need to consider when starting plastering and finishing?

When plastering a stove, you need to take into account some points that may affect the quality of the work performed.

You cannot apply plaster to a newly erected stove structure. A “fresh” stove should not only be well dried, but also go through the stages of shrinkage. To do this, it is used for two to three months, and only after this period can finishing work begin.

To paint a plastered surface, only water-based paints can be used. Other coloring compounds containing drying oil or organic solvents will release harmful substances and unpleasant odors into living spaces when the stove is fired.

For all plastering and decorative work on the stove, it is recommended to use natural-based materials, without any synthetic additives that are harmful to human health.

It should be noted that all the methods discussed in the article are not as easy to implement as they seem at first glance. Therefore, if you have a complete lack of experience in this work, you should not take risks and translate quite, sometimes, expensive materials. It is better to entrust these important activities to real professionals who know first-hand the secrets of masonry and subsequent finishing of the stove.

Evgeniy AfanasyevChief Editor

Author of the publication 28.08.2015

During prolonged use of the oven, cracks may appear on it. As a rule, this is a consequence of uneven heating of the brickwork, as well as the evaporation of moisture from the surface of the walls.

The formation of cracks can complicate the operation of the heating structure and also create unsafe conditions for users. In most cases, the problem in question occurs at the seams between the individual components of the stove. This type of masonry is usually made of refractory bricks.

What materials can be used

Traditionally, ordinary clay is used for such tasks. This is a proven material that is quite common in furnace repair work. There is also nothing unusual in preparing the solution.

It is enough to mix clay and river sand in equal proportions and mix it in such a way that there are no lumps.

To improve the properties of the solution, pass it through a sieve with large mesh.

To check the quality of the prepared solution, form a ball from the resulting mixture and throw it on the floor. If cracks appear, add more clay. Otherwise everything is fine.

How to caulk a stove correctly

To complete all the work efficiently, first of all, take gauze soaked in a liquid clay solution and apply it to the masonry. Wait until everything is completely dry. This will prevent the formation of new cracks in the future.

Before starting work, prepare the following:

Container for mixing clay mortar.
A small ladle for applying the solution to the oven.
Master OK.
Rubbing.

You can use an improved solution, which consists of the following components:

Clay.
River sand.
Horse beam or chaff.

To prepare, take 4 buckets of clay and fill them with a bucket of water. Leave the tincture container for five hours.

After the required time has passed, you need to mix the clay well and add sand (1 bucket). Continue kneading. Gradually add chaff, which will need up to 50 kg.

After preparing the mixture, cover it with oilcloth and leave until the morning. Then stir it again.

Before you begin to cover the cracks, moisten the surface to be treated with water and apply the solution in 2 layers. Apply the last one when the previous one has already dried a little.

Once you have finished coating the oven, allow it to dry completely. This process requires at least 14 days. Only then can you plaster the stove with a solution of river sand and starch.

After plastering, you need to wait another month and only then it is recommended to start whitewashing.

Features of clay

Clay is an excellent material used in the construction of home stoves, as well as their repairs. Even when dried, it has plasticity, which is regulated by the composition of the prepared solution.

Treating the furnace with cement, unfortunately, will not give such a result and soon new cracks will form on such a coating due to temperature changes.

The traditional home stove is a fairly old invention that has already stood the test of time. Accordingly, proven materials in the form of clay and sand are used in the construction and repair of such structures.

Some experts add table salt to clay to improve density and thermal conductivity characteristics. How much to add is an individual matter. In most cases, no more than a glass of salt is used for the entire solution.

Choose high-quality clay that is reddish in color. Make sure there is a minimum amount of sand in the material. Clay can be stored for the future, when it is needed for the next repair.

The unused solution will also be useful for later use. All properties of the mixture do not suffer over time. The same solution can be used to repair the chimney (also seal the cracks).

How to care for the stove

In order to repair the furnace as little as possible, the structure must be properly looked after:

Repair small cracks promptly.
The absence of minimal damage will protect the oven from major damage, which is very difficult to repair.

Thus, all furnace equipment will always be in “working” condition.

Furnace repair is a labor-intensive task. But with the right attitude and perseverance, anyone can do it. During the work you will not need to use special tools or skills. The experience gained can be gained in the future when caring for other heat sources in the house. For example, it could be a fireplace. Both of these designs have a lot in common.

When sealing cracks, pay attention to the condition of the following elements:

Doors.
Deadbolts.
Vents.
Ovens.

If there are cracks, they also need to be repaired as quickly as possible. The solution used is the same.

To prevent the stove from cracking in the house, it is necessary to responsibly carry out the work during the construction of the building. The main causes of the malfunction are laid down at this stage. But if the problem has already arisen, it is important to resolve it promptly. How and how to do this, you will learn about this in the article.

Collapse

First you need to understand why cracks are spreading along the wall of the stove.

Reasons for appearance

Before properly and reliably caulking the stove, in order to prevent repeated malfunctions, you need to know what can affect the integrity of the stove coating:

during a long break in heating the house and sudden temperature changes;
the furnace was laid using low-quality mortar;
Perhaps the reason is the settlement of the building or foundation. In this case, it will be necessary to carry out major repairs to the foundation, increasing its size and strength;
after laying the stove, the process of normal drying of surfaces was disrupted;
when plastering the stove, a low-quality solution was used or a thick or very thin layer was applied;
Perhaps the reason is faulty ventilation and condensation deposited on the walls of the furnace.

Is it possible to use a stove with cracks?

The answer to this question is unequivocal - you will need to cover up a faulty, smoking stove immediately; it is not recommended to use it. Such requirements are explained not by a violation of the appearance of the walls, but by cracks that allow carbon monoxide to enter the room. Poisoning from combustion waste can lead to dire consequences.

Firefighter statistics show that most people die in a fire because of the gas, and not from the fire.

Damage diagnostics

Therefore, at the first sign of smoke in the house, you will need to do the following:

diagnose the furnace surfaces and find the fault;
after this, immediately prepare a solution or buy ready-made material for filling cracks;
cover the walls and plaster them again.

But first of all, diagnostics will help determine the size of damaged surfaces and the approximate amount of materials to be repaired. If the mortar has simply cracked due to high temperatures, you simply need to remove the layer of plaster and apply a new layer of high-quality materials.

It’s worse if the cracks are through and continue to expand after the work has been done. In this case, it may be necessary to call specialists to identify the causes and lay a new stove. Stone stoves are a complex structure, so you shouldn’t try to lay it out from a book; it’s better to entrust this work to an experienced stove maker.

Such cracks can no longer be simply covered up

In this example, you shouldn’t cover it up either. The brick was badly cracked.

If the cracks are small and their size does not increase, you can begin to troubleshoot the problem yourself. To do this, it is important to prepare a high-quality solution and apply it correctly to the wall. How to cover up cracks in a stove so that it does not crack from the heat - knowledge of the basic materials for making the mortar will help in this matter.

Examples of small cracks:

How to cover up cracks?

For these purposes, you can use several options that will reliably seal cracks in the walls and prevent gas from escaping into the room. Let's look at each method in more detail.

Fireclay clay

Before you cover cracks in the stove with fireclay clay, you need to know its advantages:

the material is resistant to temperature during fuel combustion;
high level of vapor permeability;
resistant to moisture when heated;
environmentally friendly material, safe for humans and animals, therefore can be used in residential premises.

To make the solution you will need to mix several ingredients:

1 part cement grade 500;
2 parts fireclay clay"
7 parts river sand.

The solution is mixed well and water is added. The consistency depends on the skill and type of work, but you should not make it very liquid or thick. To get rid of stones and lumps, the clay can first be soaked in water for several hours and the lumps of material can be crushed, and the cement and sand can be sifted. Such a solution will be plastic and laid on the surface in an even layer.

Plastering walls is easy if you have a certain skill. To do this, it is important to install beacons and, distributing the solution, level the layer on the wall. You will need to prepare a trowel and spatula, the size of which depends on the surface area.

Clay and sand

This is the most affordable, inexpensive solution for plastering surfaces. Such a solution for the oven has sufficient plasticity and is not subject to destruction under the influence of high temperatures.

It’s easy to prepare the solution for use; for this you will need:

prepare a large trough in advance, add the required amount of clay and completely fill the layer with water. For 1 bucket of clay, pour 3 buckets of water. The clay should soak for 24 hours;
then mix the solution and add more water to it. We pass the slurry through a sieve, get rid of lumps and let the solution settle;
drain the excess water, making the solution as thick as homemade sour cream;
add river sand in a 1 to 1 ratio and mix the solution.

Expert opinion

Pavel Kruglov

Stove maker with 25 years of experience

Important! At this time, you can determine the quality of the solution. Having lowered the shovel holder into it, and seeing the adhering clay, in this case you will need to add a little sand. Only after seeing small clumps of sand and clay solution on the holder can you start plastering the walls of the stove.

With this solution it is necessary to repair all cracks that appear, after wetting the surfaces and then plastering the stove in several layers. In villages, they still use the old method, adding horse manure to the prepared solution. This solution is obtained with increased thermal insulation properties. Hay plays the role of air layers that prevent the free passage of heat.

Grout

This oven putty is sold ready-made, but it’s easy to make yourself. The main advantage of this material is the ability to retain its properties even when heated to 10,000. Industrial materials are used for arranging and repairing stoves and fireplaces, but the price of such grout is high, so home craftsmen do it with their own hands.

The mixture for coating the oven is made in several stages:

knead large lumps of clay and pour it into a trough;
fill it with water and leave for 10-12 hours;
pour part of the sand into the soaked clay, maintaining a ratio of 1 to 4, mix the solution well, adding 5 parts of chopped straw in small portions;
Add 1 kg of coarse table salt to the finished putty and finally mix the solution.

The finished grout can be used to fill gaps between bricks, crevices, cracks and complete the first rough layer of plaster.

Furnace glue

In order to repair a cracked stove, you can buy heat-resistant special glue at a hardware store. Due to its properties, it is not exposed to high temperatures for a long time. It consists of the addition of fireclay clay and cements with high fire-resistant properties.

A plastic and hard adhesive mixture is produced. Using hard materials, the surfaces of the stoves are plastered. Plastic glue is used to fill cracks and seams between bricks.

When using this material, you must follow the instructions when diluting and using the heat-resistant substance. You should not make it in large portions; it dries out quickly and becomes unsuitable for work.

How to properly coat a stove?

In order to reliably cover the cracks in a brick kiln, work is carried out in several stages:

How long does it take to dry?

It is not recommended to use the oven until the solution is completely dry. When using different materials, this period may vary. Using heat-resistant glue as a putty, the layer of solution will dry within a few hours.

It will take more time for the solution of clay and sand to dry and form. In this case, you will be able to use the stove only after a day. Then the brick oven, protected from cracks with mortar, will remain crack-free for a long time.

Therefore, we do not advise you to rush, immediately flooding your Russian stove with a stove bench. Repairing cracks in a furnace is a simple but important job. The choice of material for the solution is a purely individual matter. The main thing is to do the work carefully and responsibly. Then your house will always be light and clean, without the smell of burning and smoke penetrating through the cracks in the walls of the stove.

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If there is a stove in the house and the smell of smoke or carbon monoxide periodically appears, then there are cracks in it. And even a structure made of refractory bricks and fireclay clay is not immune to cracking. Although such furnaces can withstand high temperatures - up to 1000°.

Through cracks, gas enters the room, which negatively affects human health, even in small quantities. Therefore, you should not bring your furnace to a critical state; it is better to periodically carry out maintenance and cover it up.

Why do cracks appear?

There are several reasons why a stove may crack:

Poor quality putty was previously used;
Violation of finishing technology;
Improper drying;
Drawdown.

And if you can deal with the first three reasons yourself by covering the stove, then in the latter case you will have to completely relay it from the foundation to the chimney.

However, cracks are not always the cause of carbon monoxide penetration. The smell of smoke or gas may occur if:

The chimney is clogged;
Blockage in the stove riser;
The inside of the oven is not folded correctly;
Hypothermia of the riser.

The blockages will need to be removed; the supercooled riser can be warmed up with a burning newspaper. If the stove was built in violation of technology, major repairs will have to be made.

Video: Clay mortar for stove repair

Diagnostics

The first step is to inspect the stove for damage and, based on this inspection, determine the scope of work. If no major damage is found, you can get by with minor repairs, simply covering up the cracks and plastering.

If through cracks are found, major repairs will have to be carried out. In any case, when doing your own repairs, you will have to prepare a fireproof one.

Preparation of the solution

You can prepare the mixture for sealing cracks in the oven yourself or buy it ready-made. Let's look at the most popular:

clay + sand;
fireclay clay;
oven grout;
oven glue.

A mixture of clay and sand

The cheapest way to seal a stove. This option is the most common, not only because it is cheap. The prepared material has such qualities as: plasticity and viscosity. And after firing it becomes fireproof, strong and durable.

This solution is prepared as follows:
The clay is filled with water and left for 24 hours. Proportions: 1 bucket of clay and 3 buckets of water.
The next day, the clay is mixed and kneaded; water can be added as needed.
Strain the solution through a sieve with a mesh of 3 × 3 mm. and let it settle.
Drain off excess water. The mixture should have the consistency of sour cream.
Add sand as much as clay (1/1).

Stir the mixture with a stick and determine the degree of readiness. If there is a lot of solution left on the stick, it is too greasy and you need to add more sand. If a small amount remains on the stick, in the form of clots, the solution is ready for use.

The amount of sand depends on the fat content of the clay; on average, 1 bucket of clay requires 2.5 buckets of sand.

On a note! You can check the quality of the prepared solution in this way:
Take a little thick solution, make from it: a cake (diameter 10 cm, thickness 1 cm) and a ball 5 cm. Leave them to dry at room temperature and observe if cracks appear. After drying, the ball should not fall apart when dropped from a height of 1 meter. If the products crack or the ball falls apart, you need to add clay to the solution.

Before applying this mixture, the oven can be additionally reinforced. To do this, take gauze, soak it in clay milk and stick it on the stove. After drying, the oven can be sealed.

Fireclay clay

Fireclay clay is used in metallurgy, for the repair of steel smelting furnaces. It is often used in the restoration of ordinary ones. Sold in any hardware store, packaged in 20 kg bags. To prepare it, fill it with water for 48 hours.

Proportions and manufacturer's instructions for preparation can be read on the packaging. The cost of fireclay clay is not high, so it is also popular when repairing home stoves.

Oven grout

Stove grout is a rather expensive material, but it is an ideal option for renovations or fireplaces. Capable of withstanding temperatures exceeding 1000°. If this option seems too expensive to you, then you can make an analogue of this grout yourself.

To do this you need:

Pour clay into a container.
Fill with water for 12 - 24 hours.
Add sand and mix.
Add chopped straw.
Add 1 pack of salt.

Proportions: for 4 buckets of clay, 1 part sand and 50 kg. straw.

Furnace glue

This is a heat-resistant and durable material that can be purchased at hardware stores. Made from refractory cement and fireclay powder. Available in the form of plastic or solid mass.

The plastic mixture is used to cover cracks, and the hard mixture is used to plaster the entire surface. The grout is mixed in small volumes, as it dries very quickly.

Important! You can heat only after the solution has completely dried. And this can take up to a month, after which it can be whitened and used.

Video: How to repair a stove