How to repair cracks in a brick oven. How to plaster a stove so it doesn't crack. Sealing cracks and crevices on the stove

21.10.2023Heading: Solution

After a long winter, many go to the dacha for the first time this season and, getting ready to relax, light the stove in the house or in the bathhouse. And they are very surprised when they feel carbon monoxide entering the air in the room - after all, nothing like this happened last year. After a preliminary inspection, they are convinced that smoke has penetrated through the cracks that have appeared and immediately think about how to cover up the cracks on the stove.

After calling the stove maker, it turns out that there are many problems with the structure and it requires major repairs. Without telling you how to coat the stove, he immediately issues an impressive bill, which not everyone can afford to pay. In this article we will talk about the rules for troubleshooting problems of this kind, that is, we will figure out how to cover the stove so that it does not crack.

There may be several reasons for smoke in a house or bathhouse. If you see a small crack, this does not mean that carbon monoxide is coming through it; it may not be through. Therefore, you first need to correctly determine the cause of the smoke and only after that you can start thinking about how to cover up the stove.

The first option may be to clog the smoke duct with soot. If such a problem is detected, you should simply.
In the second option, cracks may appear in the chimney or the stove itself. In this case, the air supply through the ash pan decreases, the temperature of the exhaust gases decreases, and the combustion process worsens.
Smoke may occur due to improper internal masonry, or the riser itself may be clogged with brick waste. Such a malfunction can only be corrected by cleaning, or the entire chimney must be restored.
Leaving the stove for a long time can also lead to smoke. The riser itself becomes overcooled. But this malfunction can be easily eliminated: before kindling, you just need to burn a little paper, placing it in the cleaning door, and the channel will begin to work in the desired mode.

Repairing cracks

When laying and plastering a stove, it is almost impossible to ensure that the surface does not crack; cracks can occur in any equipment intended for heating. Almost anyone can eliminate this deficiency. You just need to come to the store and ask the seller what to cover the stove with. Trade workers will offer many types of putty to eliminate cracks in metal, but don’t get your hopes up too much, since a crack in metal can only be welded - any putty can only help for a very short time.

Spider web cracks

Many people observed that the plastered surface of the stove was cracking, forming a web of small cracks located close to each other. These are small, non-through cracks that spoil the appearance of the structure. You can and should get rid of them, as the shedding of the plaster will only increase. The surface of the plaster cracked as a result of the solution being prepared incorrectly. How can this defect be corrected? The work order is as follows:

Clean the surface. Use a chisel to knock out the cracks.

Attention: do not knock out one crack at a time. Completely clear the area of formation. Moreover, cleaning should be done to the hard surface of the brick. If you don't do this right away, the cracks will reappear.

Clean the hard surface with a metal brush.
Moisten the surface thoroughly with primer. To do this, you can simply mix cement with water and bring the solution to a liquid state. Lubricate the cleaned area with the resulting solution using any brush.

After breaking up the cracks, we get planes that need to be plastered again. The surface is primed and dry. At this time, you need to prepare the correct solution for the plaster. Plastering a stove in a bathhouse or in a house should be done with a clay solution. For the correct proportion of clay and sand, the fat content of the clay should be determined, this can be done like this:

We make five test samples of clay mortar. We mix clay with sand in different proportions.
Sift the resulting mixtures through sieve with a cell of 1.5 mm.
Add water and bring it to a plasticine state.
Making balls diameter 5 mm and drop them from a height of 1 m onto a hard surface. The one that won't break will have the right ratio of sand to clay.

After determining, we knead in the required quantity and begin plastering the area where we cleaned. The area was treated with primer. If it is completely dry, it should be moistened with a spray bottle to keep it moist.

Using a trowel, apply the clay mixture to the wall of the oven. Use the spraying method (the solution in small parts is simply thrown onto the wall and sticks).
Using a large wooden grater, level the surface, while lightly pressing the tool.
We are waiting for the mixture to dry.
We fill cracks and depressions with clay mortar using a triangular trowel. If the finishing area falls on a corner, we apply a wooden plank to this place and use it as a limiter.
We take a wooden grater and treat the surface with it. We wet and rub in a circular motion, pressing the tool slightly.
Let the surface dry.
Using a metal trowel, spray the final layer of mortar, moving from bottom to top.
Let it dry and use a wooden grater, previously soaked in water, to rub it in a circular motion until the unevenness completely disappears.

Other types of cracks

If, then small cracks are rubbed with a solution of alabaster and chalk. Elements of the tile that have received defects as a result of heating are simply replaced with others. In this case, a clay solution is used. Before installing a new element, the mounting area should be thoroughly cleaned of old mortar and moistened. Sometimes cracks are formed due to loosening of furnace devices (doors, valves, etc.). In this case, you should remove the door from the masonry. The mounting area is completely cleaned.

A hole is made in the masonry for fasteners (wire).
A wire is attached to the door frame, and the frame is wrapped around the perimeter with asbestos cord.
After this, a clay solution is applied (the preparation process is described earlier).
The door is firmly inserted into place and secured with wire.

Sometimes cracks form in the masonry of the firebox or the first chimney channels; the brick simply remains loose in the structure. This brick needs to be moved:

To fix the problem, you should select a high-quality brick. The temperature is highest here. In other places where brick is replaced, a material of lesser quality will be suitable.
The walls of the brick must be smooth. Inside the channels, friction of gases occurs against the walls of the chimney surface, so they must be as smooth as possible.
Having pulled out the brick, we clean the surface of the old mortar using a metal brush.
Place the clay solution on the cleaned surface.
We lay the prepared brick in place of the fastener. As a rule, the internal brick is attached to the mortar on all sides. More mortar should be placed on the bottom of the brick stack so that when a replacement is inserted, by pushing the brick in, a mound of mortar is formed on its back surface and when pressed, all cavities are filled.
If cutting of bricks is required during the work, we lay it so that the smooth surface is directed towards the exhaust gas outlet. These surfaces cannot be rubbed down; the clay will dry out and crumble, which will clog the channel.

Sequence of correct furnace firing

before kindling, you should always clean the ash pan, put dry wood chips on the grate, close the ash pit and set fire to the food;
place firewood in the firebox and open the vent completely, this warm air will break through the stagnant air in the pipe and adjust the operation of the chimney; the second load of firewood should be made when the first one burns down to the state of large coals;
do not fire with peat, and especially with coal in a furnace, the solution of which is made without the addition of fireclay powder: the usual mixture can only withstand the burning temperature of firewood; under the coal, fireclay powder is added to the batch, which increases the heat resistance of the structure;
coal combustion is not carried out on grates made of metal and metal furnaces: metal burns out extremely quickly from the high temperature of the coal;
Load the corner after the oven has warmed up strongly.

Attention: if you call a stove-maker who does not ask what the stove is heated with, this should raise concerns about his competence. Remember: when using peat and coal briquettes in the firing process, repairing masonry and sealing cracks in the furnace are carried out only with the addition of fireclay powder.

Repairing cracks in metal furnaces

Sometimes cracks occur in metal structures. And here you shouldn’t think about how to coat the stove; only welding will help in this matter. As a rule, they appear after improper use of the structure, which is also affected by rapid loading of solid fuel. But this problem can be fixed:

We prepare the crack. If it is small, you need to make holes along the edges of the crack, but in metal that has not yet been fractured. This is done using a drill with a drill bit that is twice as large as the crack itself.
After preparation, we perform welding with a welding machine. We make a wave welding seam.
After welding, we clean the seam with a grinder.
If the crack is large enough ( width more than 5 mm), you should cut it out with a grinder, make a metal patch according to the thickness of the oven wall and weld it.

Attention: if the stove has just been laid, and the next season cracks already form in the masonry and several bricks fall out in one place, do not try to repair it, it will be wasted money. In this case, most likely, the channel was laid out incorrectly or poor-quality material was used during installation. If you do not completely redo this section of the structure, you will pay for cosmetic repairs every year.

When installing the stove, monitor the quality of the material and the correctness of the work. This will help you avoid cracks and breakages.

Every owner of a heating unit certainly faces the problem of how and with what to coat the stove so that it does not crack, even if it is made of refractory bricks and sealed with a mortar using fireclay clay. Sooner or later, cracks may appear on this structure.

Why do cracks appear on the stove?

The reasons why they are formed are:

violation of masonry technology;
use of low-quality building materials;
uneven heating of the stove surface.

The presence of through cracks poses a potential threat to the health of everyone living in the house. Carbon monoxide begins to penetrate into the room through them. Therefore, it is so urgent to solve the problem than to cover up cracks in a brick oven. In this case, repair work must be organized immediately.

Crack repair work

This process can be divided into several stages:

Diagnosis of existing damage.
Preparation of the solution.
Plastering the heating structure.

Stage one – damage diagnosis

Before coating the stove, you should assess the extent of the existing damage in order to find out the scope of the work to be done. If the cracks are minor, then surface measures will be sufficient. To do this, the bricks are cleaned of finishing materials and plaster, the damage is repaired and the stove is plastered.

If there are large through cracks, damage to the masonry or cladding, the heating unit must be disassembled to make repairs.

Stage two - preparing the solution

Regardless of the size of the damage, you need to prepare a special solution to putty the oven. Depending on financial capabilities and the availability of materials, certain types of mixtures are used when carrying out repairs.

They are:

from fireclay clay;
from sand and ordinary clay;
in the form of grout for the stove - you can make it yourself or buy it ready-made;
from oven glue.

Fireclay clay

Most often, fireclay clay, which has excellent fire resistance, is used to restore a brick structure. Stoves made with this material are reliable and durable. Many people don't know where to get clay. This clay is sold in every hardware store - it is packaged in paper bags weighing 20 kilograms.

Sand and clay

You need to follow the procedure for preparing clay for coating the oven. It is first soaked in water and left for 2 days. The cost of fireclay clay is affordable.

A mortar made from ordinary clay and sand is the most inexpensive solution than covering up cracks in a stove between bricks. It is used quite often, since the mixture is plastic, and after firing it becomes durable and strong.

How to prepare clay

This solution is prepared in the following sequence:

The clay is poured with water in a ratio of 1:3 and allowed to brew for 24 hours.
After a day, it is stirred by adding water. The resulting mixture is filtered through a sieve with a mesh size of 3x3 millimeters and settled.
The water is drained, after which the thickness of the clay should resemble the consistency of sour cream.
Sand and clay are mixed in equal proportions.
The readiness of the solution is determined by stirring it with a stick. If there is a lot of clay left on it, then you need to add sand to the mixture. The solution is ready when small clots stick to the stick.

Usually take 2.5 parts sand to 1 part clay.

Special putty is what you need to coat the oven with to prevent it from cracking

You can buy this mixture for eliminating cracks or make it yourself. Fireproof putty for stoves and fireplaces purchased at a building materials store is ideal for repairs. It perfectly withstands temperatures of 1000 degrees. Before applying it, the stove and cracks should be treated with water.

You can do the grouting yourself, following the instructions:

Pour clay into a container and break up the lumps.
Fill it with water and leave for 12 hours.
Pour sand into the clay and knead the mixture.
Finely chopped straw is added in small portions.
Add one pack of salt.

Sand and clay are mixed in a ratio of 1:4. For 4 buckets of clay you will need about 50 kilograms of straw.

Oven adhesive composition

Building materials stores sell special glue designed for repairing stoves, which is durable and heat resistant. For its production, refractory cement and fireclay powder are used.

They produce plastic and solid mixtures. The first of them is used to fill the cracks, and the second is used to plaster the entire stove surface. The main advantage of oven glue is that it dries quickly.

How to coat a stove with clay

The choice of how to seal the stove so as not to crack depends on what mixture you decide to use. But first you need to clean the bricks from the plaster and the layer of finishing material. They are then treated with a solution.

If you decide to use a clay mixture, then you need to follow the instructions on how to properly coat the stove with clay:

The prepared solution is stirred one more time.
They check its quality. To do this, roll the mixture into a ball and if it starts to crack, then add water.
Before coating the stove with clay to prevent it from cracking, the damaged areas are moistened with water.
The cracks are filled with the solution.
Then the oven can be plastered.
Despite the fact that the repair of the brick kiln is completed, you should not rush to heat the unit, since the solution must dry completely.

If you carry out repair work in full accordance with the instructions on how to coat the stove with fireclay clay to eliminate cracks, then you can forget about them for a long time.

The stove appeared in Rus' more than 4 thousand years ago. Its prototype was a smoking hearth; later a chimney was added to it. For a long time, the design of the stove remained approximately the same and resembled a heater, which can still be found in village baths. They were rectangular in shape, low and had a size of 1x1 m. The stove was built from stones of different sizes: large, flat stones were used for the lower part, and smaller ones were used for the top. They were not fastened together with any solution. Sometimes a mixture of clay and shards of broken pots was used to seal the cracks between the stones. Over time, the stove acquired the appearance that it has retained to this day. It was built from clay or brick.

In Ancient Rus', the stove was the main attribute in the hut, and the stove maker was treated with no less respect than the clergyman. The stove warmed the house; it was used to cook food, bake bread, and even cure various diseases. Modern stoves can be divided into several types: heating, heating and cooking, Russian (oven), fireplaces and sauna stoves. Their laying requires great skill and skill and remains a difficult task in our time.

But even a well-built stove may require repairs during operation.

This is most often associated with the formation of cracks through which cold air penetrates inside. As a result, the stove begins to smoke and heat worse. It happens that the plaster on a previously whitewashed stove begins to crack and crumble and spoils the appearance of the entire room. In such cases, you should know how to cover the cracks and coat the stove.

The most reliable method for coating stoves is a clay solution.

You can now find special mixtures for coating ovens on sale. For example, experts recommend using a refractory mixture, which is ready-made clay, to seal cracks. Before use, it must be diluted with water, following the instructions, to the desired consistency, add PVA at the rate of 100 g per bucket of solution and you can seal the seams that have crumbled over time or coat the entire oven. But still, the most reliable method is considered to be one that has been tested for centuries - plastering with clay mortar. This finishing option is the simplest, most common and, with proper preparation of the mixture, will last a long time.

To obtain the solution you will need the following tools and materials:

A construction sieve with a hole size of at least 3 mm.
Sealed container (trough, bathtub or tub).
Bucket, shovel.
Clay, sand.

To coat the stove, it is better to use solutions containing crushed asbestos, which are more elastic and fire-resistant.

This is a recipe for a classic solution in which clay and sand are mixed in a 2:1 ratio. Our ancestors added fine straw or horse manure to it to avoid the formation of cracks. For the same purpose, experienced professionals advise adding table salt to the solution (300 g per 10 l). This putty should be allowed to sit overnight before use. But the use of these mixtures does not always achieve the desired quality. To coat the stove, it is better to use solutions containing crushed asbestos, which are more elastic and fire-resistant.

0.1 part asbestos, 1 part lime and clay, 2 parts sand;
2 parts sand, 1 part each clay and cement, 0.1 part asbestos;
2 parts lime, 1 part gypsum and sand, 0.2 parts asbestos.

Preparing the mixture

The clay can be pre-soaked for a day, in this state it will mix better with sand.

Materials must be measured by volume in accordance with the required quantity. Before starting work, all components should be sifted through a fine sieve. The clay can be pre-soaked for a day, in this state it will mix better with sand. The lime is first slaked with water, and the resulting milk is mixed with the other components, depending on the composition of the mixture. The prepared solution should be homogeneous and have a fairly thick consistency. If necessary, it can be diluted with water.

Mixtures with cement and gypsum are prepared in small portions. It is advisable to use a cement solution within 1 hour; a solution with the addition of gypsum is suitable only for 5 minutes. Then they lose elasticity and become unsuitable for use.

A soft mesh of iron wire will be needed to coat the entire oven.

The resulting solution can simply be sealed without further caulking of the furnace. To do this, the cracks must be thoroughly cleaned and moistened with plenty of water, then coated with the solution and rubbed. When the oven heats up too much, thin cracks may appear on it, which disappear when cooled and do not require grouting.

To coat the entire oven you will need the following tools:

Paint brush.
Putty knife.
Construction knife.
Hammer, nails.

First, you need to clean the brick and thoroughly clear the masonry seams to a depth of 1 cm. After this, you need to cover the stove with a metal mesh and nail it in a checkerboard pattern at a distance of 10 cm, getting into the seams between the bricks. The coating is made on the basis of this mesh. It is recommended to carry it out on a hot stove surface, since as a result of preheating, the seams expand and will better hold the plaster. In turn, the pores of the cooling brick will also attract mortar. The oven is moistened with water and coated with the mixture in two steps. The first layer is more liquid (for this the solution is diluted to the thickness of sour cream) 5 mm thick. The second thicker one is applied on top and has the same thickness. Then the layers are leveled and rubbed. If cracks form after drying, they must be cut and the edges trimmed. Then moisten with water and rub with a thick solution.

Reading time ≈ 3 minutes

Autumn has arrived, followed by cold winter. Residents of private houses begin to light their stoves, and are surprised to see that the smoke, instead of quietly escaping through the chimney, enters the living room. In order not to think about how to cover up the cracks in the stove, they invite a stove maker. The repairman who came explains that the problems are serious, and, without telling us how to cover the stove so that there are no cracks, he issues a tidy bill, which is frightening in its size. In order not to pay unreasonably inflated bills, not to wait for a repairman to arrive in a cold house, you need to figure out on your own what you can use to coat the stove.

Causes of stove smoke

The reasons why smoke does not escape through the chimney, but spreads throughout the house, can be varied. The most common one is a chimney clogged with soot. When soot is removed, heating quickly improves and problems no longer arise.

If no one has lived in the house for a long time, then putty for the stove will not be needed. A frozen chimney begins to work incorrectly, but the malfunction is easily eliminated. It is enough to warm up the riser by burning the paper, and the smoke will follow the desired path.

If you do not know whether the stove worked before, then malfunctions in its operation may be caused by improper laying of the chimney or clogging of the channels with parts of bricks. In this case, major repairs cannot be avoided.

Well, and, of course, cracks in the chimney or in the stove itself lead to disruption of its operation and the appearance of smoke in residential areas.

How to cover the stove to prevent it from cracking?

Cracks in the stove are inevitable, but any person can fix minor problems.

The most common cracks that appear on heating appliances are spider webs. A network made up of small, non-through cracks that spoil the appearance. They must be removed because they will gradually cover a significant surface area.

Before repairing the stove in the house, you need to thoroughly clean the damaged area and knock out areas where cracks have formed with a chisel. The cleaned surface must be cleaned with a metal brush. After this, the cleaned part is moistened with a primer. When the primer dries, the cleaned area is plastered with a mixture of clay and sand.

Often cracks appear in places where stove elements are attached, for example, the firebox door or ash pan. Before coating the stove to prevent it from cracking, in this case you must first completely pull out the door, thoroughly clean the damaged area, and only then can you begin restoration work.

Before caulking the stove, it is necessary to secure a wire to the door frame so that it does not fall out in the future. An asbestos cord must be laid around the perimeter of the door, and all other work must be done in the same way as when eliminating cracks with cobwebs.

Heating a room in private homes using a stove remains a popular heating method today. Therefore, solving problems associated with this process is relevant. The most common damage in a furnace is the presence of cracks. In this case, it becomes unsafe to operate the stove, since carbon monoxide, even through small cracks, will seep into the room.

When faced with troubles, owners often think about how to repair the stove.

What causes defects

Before repairing damage, it is necessary to find out the causes of cracks. These include:

low-quality mortar used when laying the stove;
violation of the finishing process;
shrinkage of the structure;
sudden heating;
violation of the rules for using the stove.

If the stove shrinks due to the foundation being poured incorrectly, the doors will not close tightly. Then the masonry will begin its destruction, and smoke will then pour out of all the cracks. In this case, it is urgent to dismantle the entire furnace structure, strengthen its foundation and lay out the furnace in a new way. Sometimes you don't have to resort to such radical measures. Small shrinkage in the first two years is considered acceptable. If small cracks appear, it will be enough to simply seal them.
The remaining causes of defects are easily eliminated. It is important to properly seal the stove so that it does not crack in the future.

Troubleshooting

First, you need to carefully examine the damage to determine the scale of the work. If the surface of the structure is riddled with many small cracks, you will first need to free it from the cladding, then clean the entire masonry of plaster. Next, you can begin to cover the cracks. Here the question arises: what solution is needed to protect the stove from further damage. To do this, you can use one of the mixtures proposed for consideration:

composition of clay and sand;
grouts designed specifically for ovens;
fireclay clay;
special glue for the oven.

What kind of putty should I use?

Clay and sand

Covering cracks with a clay mixture is the most economical and easiest way to restore a stove structure. You can use any clay. It is important that it contains a minimum amount of impurities. If the raw material is of high quality, then after soaking it should have an oily, homogeneous and, most importantly, plastic structure. At the same time, the quality of restoration is no worse if the stove was repaired using expensive modern means. Before you start covering with clay, you should understand the features of preparing the solution.

How to make clay putty yourself

The preparation of the mixture is done in stages.

Before mixing the components, the clay must first be kept (soaked) in warm water for 12 hours.
Knead the softened clay until smooth so that there are no lumps left in it.
To obtain a mixture for putty, you need to take clay and sand in a ratio of 4:2, respectively. The last component should be pre-sifted. The amount of liquid is taken depending on the moisture level of the components.
If you want the stove to be white, add lime to the putty and knead everything thoroughly until a homogeneous consistency is obtained. The prepared mixture is covered with polyethylene and kept for 12 hours.
The settled compound is kneaded a second time. Roll a piece of putty into a ball in your palms and squeeze it. If it starts to crack, you need to add water to the mixture.
Lightly heat the oven, spray water into the cracks, and then start caulking.
To prevent new defects from appearing, straw is added to the clay. A more reliable method is to use a plaster mesh. If the solution is applied to a surface covered with this material, you will forget about cracks for a long time.

Fireclay clay

Fire clay is often used to repair old stoves. The material has increased fire resistance. Furnace structures finished with it are durable.
This material is sold in all construction stores and markets in 20 kg bags. It's inexpensive. The working mixture is prepared strictly according to the accompanying instructions placed on the packaging.

Grout

As a putty for brick stoves, you can use grout designed specifically for this purpose. Various similar formulations are sold in stores. They are expensive, but they are the best option for lining brick stoves, as well as fireplaces.
If you are on a budget, prepare this remedy yourself. To do this you will need clay, sand, water, straw and salt. The clay should be thoroughly kneaded and filled with warm water. After 12 hours, add sand four times less than the first component to the mixture and knead, gradually adding finely chopped straw, not forgetting the salt. For four buckets of clay mixture, take 50 kg of chopped straw and a package of salt. The resulting composition can withstand temperatures exceeding 1000 degrees. Celsius.

Furnace glue

To prevent the formation of cracks in the stove structure, heat-resistant glue is used. This is a ready-made building material used for lining fireplaces. Sold in all construction stores and markets. Its main properties are heat resistance and durability. The adhesive composition consists of fireclay flour and cement with fire-resistant qualities. Glue for stoves can be soft or hard. The plastic product is used to seal cracks. The second is for plastering the surfaces of the stove. The main advantage of the glue is its almost instant drying. Therefore, it needs to be mixed in small quantities.

Sequence of work

The method of applying the sealant depends on the type of mortar.
To repair cracks using a homemade mixture of clay and sand, the work will not cause any particular difficulties.

First, the brick should be cleaned of the previous facing building material and plaster.
Then you need to warm up the oven a little and spray all the cracks with warm water. This must be done so that the dry masonry does not absorb liquid from the caulking composition. Otherwise, it will lose its qualities along with moisture.
Now you can start the main work. To begin with, you need to press the product tightly into the cracks, and spread the remaining mixture evenly over the surface. These actions can be performed with your hands without construction gloves, since homemade putty is an absolutely harmless building material.
The final stage is plastering of the masonry. Keep in mind that you can use the stove after the putty has completely dried!

Let's consider the option of covering the stove so that it does not crack in the future with heat-resistant glue specially designed for this purpose. The process of restoring a heating item is similar to the previous one. The difference is that upon completion of the elimination of cracks using an elastic composition, the surface of the stove is covered with a solid fire-resistant adhesive mixture. The glue dries quickly enough, in no more than 30 minutes. Therefore, the decorative design of the stove can be carried out on the same day.

In this story, we discussed how and, most importantly, how the stove structure can be restored so that in the future neither it nor its lining is damaged. In conclusion, I would like to note to you: even high-quality fireproof and expensive products will not be able to protect the stove from cracks. The main thing here is not the quality of the caulking material. The technology for constructing a heating structure and its repair is what must be strictly observed. If you build a stove according to the rules, slowly and thinking about every step, it will serve you for many years.