How to cover the stove to prevent it from cracking. How to cover a brick oven. Oven grout

Even the most durable stove can crack over time. If you ignore the need for repairs, the heat source will not last long. The question is: how to cover a stove - brick or metal? The article discusses the causes of cracks and how to eliminate them.

Figure 1. Cracks in the furnace

Why do cracks appear in furnaces?

Most often, problems appear in brick fires. There are 4 main reasons for violating the integrity of the masonry:

• prolonged absence of heating in the house; if the stove stood in an unheated building during the winter, then cracks cannot be avoided - and not only in this structure, but also in the walls of the building;
• ignoring operating rules; a “fresh” stove must stand – the masonry mixture should set and the structure should dry well; heating a damp hearth will certainly lead to the appearance of cracks;
• uneven heating of furnace zones; the structure must be made in such a way that heat is distributed evenly throughout it; otherwise, the thermal contrast boundary line will become clearly visible - the masonry will crack in this area;
• difference in thermal expansion coefficients of masonry mixture and masonry; the furnace material and the solution must have approximately the same thermal expansion rates, otherwise the surface will be covered with a network of microcracks; This is not the biggest problem - cracks are not visible on a cold structure.

These four reasons lead to troubles that can be relatively easily eliminated with putty. But there are more fundamental reasons:

• improper foundation design; if the latter, for example, does not correspond to the dimensions of the heat source, the stove monolith will be damaged; the oven will begin to crack even if the shrinkage of the base does not go according to plan;
• incorrect calculation of physical characteristics of materials; for example, without a reserve in thermal seams, the metal structure will “break.”

In these two cases, putty will not help. We'll have to move the oven. Therefore, the first step is to diagnose the structure. Once you are sure that the problem can be solved with little effort, you can proceed to the next steps.

Important! Before repairing, you need to make sure that restoration can be done. There is no point in sealing cracks if the cause is fundamental

How to cover up cracks?

You can cover the stove with a purchased mixture or a solution you prepare yourself. Further about the features of the options.

Sand-clay mixture

Putty made of clay and sand is the most accessible and inexpensive option. Scheme for preparing the mixture:

• you need to take clay and fill it with water in a ratio of 1:3; after this you need to leave the mixture for at least a day;
• The clay should be thoroughly mixed, adding liquid from time to time; after kneading, strain with a fine-mesh sieve and tincture again (several hours);
• after the next infusion, you need to drain the water and make sure that the mass has a creamy consistency;
• you need to mix clay and sand - first in equal proportions.

Readiness is determined using an object used to mix the solution. If too much clay sticks to it, add a little sand. As a result, the ratio of components can be from 1:1 to 1:2.5. The composition can be considered ready when a small amount of the viscous component remains on the stick.

This recipe is approximate as clays can vary greatly. It is best to rely not on a stick with stuck clay, but on the result of experiments. Experienced craftsmen make grout with different compositions. After this, several different types of cakes are dried in a place free from sun and wind. Those pieces that are not cracked are dropped from a meter height. “Surviving” flatbreads demonstrate the optimal ratio of components.

Read also: review and preparation of material.

Fireclay putty

A slightly more expensive, but also more effective option. Fireclay clay is very heat-resistant and durable. Most often, fireclay is used for stove repairs. The material is sold by construction stores. Before sealing the structure, purchased clay is infused in water for a couple of days.

Oven adhesive

If you need the best option, use a special mixture for ovens. The solution consists of fire-resistant cement and fireclay powder. There are two main types of glue you can buy in supermarkets - viscous and hard. If you are looking for something to cover up small cracks on the stove, purchase the first type. Solid mixtures are used for plastering.

The main advantage of factory materials is the optimal ratio of components and very thorough mixing. It is impossible to achieve such quality at home. In addition, there is no need to waste time preparing grout. Another advantage of ready-made compositions is quick setting.

An alternative option is oven grout.

Factory solutions are good for everyone, except for the price. There is another opportunity to save money - use putty prepared according to the following recipe:

• the clay is broken into small lumps and infused in water for about 12 hours;
• sand is added to the mixture of water and clay, after which the components are thoroughly mixed;
• during the mixing process, crushed straw is added to the composition from time to time, which reinforces the solution;
• After the mixture becomes homogeneous, salt is added to it (about a pack).

The ratio of sand and clay is 1:4. You need about 10-15 kg of straw per bucket of clay. It is easy to see that this is a modified version of the sand-clay mixture described above.

How to cover up cracks and plaster a stove?

To prevent the stove from cracking, you need to take a competent approach to its construction and operation. But if cracks do appear, they need to be eliminated as quickly as possible. Regardless of the type of mixture, the structure should be prepared before restoration. The surface is cleaned of dirt and debris, and the cracks are deepened and widened. If there are bumps and sagging on the base, they are knocked down.

Remember! If the oven begins to crack due to insufficient shrinkage, you need to let it sit completely. Otherwise, after repairs, the structure will again become covered with cracks.

Before coating, the hearth must be heated. Due to the high temperature, the furnace materials will increase in volume. This will avoid repeated cracking immediately after post-restoration heating.

If there are few “seams”, they are sealed locally before plastering. Otherwise, a complete coating is used - the entire surface is covered with liquid heat-resistant putty.

Scheme of work

In general, the procedure is as follows:

• clean the base and perform other additional work;
• cover the surface with a thin layer of liquid mixture and allow the putty to dry;
• reinforce the base (or cracks, if the repair is local); for this purpose, a metal mesh with small meshes is used; fasten the reinforcement with nails or dowels; as an alternative to the mesh, you can use burlap soaked in putty; It is preferable to use it to seal cracks pointwise;
• after the starting layer has dried, the fireplace is plastered; the oven is coated in two layers - the thickness of each layer is no more than 5 mm.

The next steps are at the discretion of the stove owner. The structure is covered with whitewash or decorated in another way.

How to eliminate cracks in a metal structure?

The main solution to the problems of cracks in metal stoves is obvious - welding is used. But if this option is not suitable, you can use special fire-resistant putties.

Recipes for preparing mixtures are presented in the tables.

Conclusion

To prevent the stove from causing trouble, you need to think about possible problems already at the design planning stage. But if the heat source does crack, in most cases it can be fixed with caulking and plastering. And only if this does not help, the oven will have to be disassembled and rearranged.

The condition of the furnace requires regular monitoring. The refractory brick, bonded with fireclay clay mortar, from which the stove is made, although capable of withstanding high temperatures, does not last forever. Over time, cracks may appear in the furnace masonry due to uneven heating the material. Using a fireplace with through cracks poses a danger to human health, since harmful carbon monoxide penetrates into the room through them.

Consequently, the questions arise: how to cover the stove in order to prevent the appearance of cracks in a timely manner, how to eliminate the damage that has appeared, and what to do so that it does not crack anymore?

Material for filling cracks

There are many sold in hardware stores for filling cracks. The heat-resistant mixture will only need to be diluted with water, and it will ready for use.
You can resort to traditional methods, which are no worse. The most common remedy is a solution of clay and sand, which should be used to coat the damage. Asbestos, lime or salt can be added to such a solution for better effect.

If the solutions are ineffective, you can resort to more radical methods. For example, for the manufacture of a metal frame.

It will be necessary to make it from aluminum sheets pieces of metal according to the size of the furnace. They should be secured to the heating element on the sides with metal corners. Then it is recommended to apply heat-resistant radiator paint to the metal.

Damage repair technique

If the stove is cracked, immediate action should be taken. If you follow all the rules that will help solve the problem efficiently, your stove will last a long time.

Furnace diagnostics

First, you need to carefully inspect the stove, both outside and inside, and determine the extent of damage. If the oven has serious defects, it will need to be completely repaired. disassemble and restore. If there are small cracks, then it will be possible to coat and plaster them, having first removed the layers of finishing and plaster down to the brick.

How to coat a brick oven? The issue is relevant not only for residents of villages and hamlets, but also for owners of summer cottages. As you know, the functions of the simplest brick oven in a village house are: the process of cooking food and at the same time heating the room. However, even the most well-installed brick stove begins to become covered with cracks over time.

In this regard, there are several compositions of mixtures that can be coated with a brick oven, so that even small cracks do not subsequently cause global destruction of the structure and allow it to serve for many years.

The main signs indicating that it is time to start restoring the furnace are its smoke and poor heating of the room. The reasons for this may be through cracks formed between the bricks, which will subsequently need to be rubbed or covered up.

Classic grouting of cracks in a brick kiln consists of the following main steps:

1. Wetting the cleaned area of ​​the area to be coated with primer.
2. Preparing a solution from fireclay heat-resistant clay, river sand and ordinary water in a 2:1:1 ratio, to which you will then need to add dry construction adhesive in a small amount (for the best adhesion of the solution to the surface to be sealed).
3. Cleaning - knocking out places where cracks form using a chisel and subsequent treatment with a metal brush, cleared of excess, already old elements of the damaged surface.
4. Plastering the dried brick oven area after priming with clay-sand mortar.

In brick kilns, as a rule, the main cracks most often appear in the places where such elements are attached, such as the firebox doors or the vent. Therefore, before coating a brick stove with a clay heat-resistant mortar, you must first completely remove the firebox door, then just clean the damaged area and finally begin restoration work. In order to cover the problem area with clay, it is also recommended to fasten a wire (asbestos cord) around the perimeter to the door frame until the cracks are eliminated in order to firmly fasten it to the brickwork of the stove.

Sealing cracks in brick structures with gypsum-based mortar

In traditional Russian brick ovens, sealing of cracks formed during operation is best done with a gypsum-based solution.

Necessary equipment

In order to prepare the solution and repair the furnace, you will need:

• container for mixing the mixture - a trough or tub;
• measuring bucket, construction sieve with a hole size of at least 0.3 cm, shovel;
• spatula, paint brush, construction knife, hammer, nails;
• soft mesh made of iron wire or natural burlap, asbestos cord;
• gypsum powder, cement or heat-resistant clay as the main element with the addition of river sand, asbestos and construction glue;
• lime with chalk for whitewashing.

All dry building components (materials for grouting cracks on brick stoves) must be measured in accordance with the required quantity and then be sure to be sifted through a sieve before mixing.

Cladding process

Solutions based on gypsum or cement are prepared in small portions. In this case, it is recommended to use the cement mixture for 1-1.5 hours, and the gypsum mixture for 5-10 minutes, since after this period they lose their elasticity and become unsuitable for further restoration work with them.

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Tip: it is advisable to soak fireclay or other fireproof clay in water for about a day, since in this state it will mix better with sand.

Lime, before adding the appropriate components, depending on the composition, is slaked with water. It should have a homogeneous, fairly thick consistency, which, if necessary, can then be diluted with a small amount of liquid.

Restoration work on sealing cracks in brick kilns using gypsum-based solutions must be carried out quickly enough and in small volumes, otherwise the entire preparatory part, unfortunately, will be repeated, which is undesirable for such a structure

Sealing cracks with gypsum mortar is very durable and aesthetically pleasing. After applying the mixture to the problem area of ​​the oven, it should be immediately brought to a smooth and even state using a spatula.

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The advantage of clay coating of a brick oven is that it is less complicated, but also guaranteed to eliminate cracks or cracks. In any case, the choice is yours.

The stove is the heart of the home and therefore requires constant care. In this case, the pipe can be made of bricks, stone or made of metal. Every owner, when installing a stove, dreams of its long existence. However, this element is constantly exposed to temperature changes and requires periodic repairs.

Prevention

Regular preventive inspections do not allow the stove to fail, but troubles can very rarely be avoided; cracks do appear on the surface of the stove walls. Therefore, the question of how to cover up cracks in the stove is relevant for many owners.

What causes cracks to form on the stove?

A careful visual examination allows you to detect a large number of small cracks on the stove walls, which appear due to different rates of thermal expansion of brick and masonry mortar. These cracks can be easily repaired using a stove coating mixture.

If heating occurs unevenly in different parts of the furnace, the result is rupture of the masonry joints. This problem can also be solved simply by covering the crack with a new solution.

Cracks can form as a result of improper operation, when only the folded stove begins to be fired. However, even in this case, the problem of how to cover the stove is solved with the help of masonry mortar and plaster.

More serious are cracks that appear as a result of different thermal expansion of the materials used to lay the furnace. It is worth remembering that different expansion coefficients are observed for red, refractory, refractory brick and stone. Therefore, it is necessary to understand the question of how to repair cracks in a brick stove.

The lack of reserve in thermal seams also causes rupture of masonry on cast iron appliances.

If the dimensions of the furnace and the foundation do not match, or if it shrinks unevenly, cracks also appear.

How can I cover and seal stove cracks?

One of the options for solving the question of how to repair cracks in a stove is tiling. Moreover, you can use clinker tiles, porcelain stoneware, terracotta or tiles. If you follow all the subtleties of working with these materials, you can forget about stove repair for a long time.

However, this option is not available to everyone, since such finishing materials are quite expensive. Therefore, there is a budget finishing option - plastering the surface. Moreover, it is very important to know how to rub the stove so that it does not crack.

Plastering without cracks is possible only if a certain sequence of work is observed, and this applies to both the initial application of the solution and repairs:

• The installed stove must stand for at least 6 months for complete shrinkage and drying.
• Before covering the stove with clay, it is recommended to warm it up thoroughly. This will expand the volume of the masonry and prevent the formation of cracks immediately after coating.
• Before coating the oven with clay, the surface must be thoroughly prepared. To do this, remove the old coating, widen and deepen the cracks, and smooth out the sagging.
• The prepared surface of the stove walls is covered with a thin layer of liquid mortar and left to dry.
• Next, burlap or a metal mesh with small cells is fixed to the wall. This will make the plaster layer more durable. Before laying, the burlap should be soaked in a liquid plastering solution. The metal mesh is secured with nails, which are driven into the masonry joints.
• For spot repairs, it is enough to cover the cracks with a thick layer and cover with burlap.
• The plaster itself is applied in two layers, the approximate thickness of each layer should be about 5 mm. Thicker application may result in uneven and unstable coverage (read also: " ").
• The slightly dried surface is rubbed and leveled.
• A finishing layer of lime mortar or chalk whitewash can be applied on top of completely dry plaster. In both cases, the use of heat-resistant pigments is allowed.

Methods for filling cracks - coating mixtures

When deciding what to coat the stove with to prevent it from cracking, it is important to carefully consider all the options.

If a clay solution was used for laying bricks, then it is recommended to cover up the cracks with it too.

To prepare the solution, you need to take clay and sand, and in different situations different proportions of materials are used.

Most often, sand and clay are taken in a 1:1 ratio, but depending on the type of clay, the proportion may vary.

To choose the correct answer to the question of how to cover the cracks in the oven, you need to prepare several solutions and make cakes and balls from them. After drying naturally for a certain time, select the least cracked cake.

The next experiment is carried out with clay balls, which are thrown from a height of about a meter. And again they choose the strongest figure.

The most suitable solution for solving the question of how to coat a brick oven is a mortar from which the figurines are not cracked or crumbling.

When preparing the solution, remember that a large amount of sand reduces the strength characteristics. However, the solution shrinks slightly.

In the question of how to dilute clay to putty a stove, the amount of water in the solution is also of great importance: with an increase in the amount of liquid, the risk of cracking decreases.

A high-quality solution has a homogeneous structure, so it is necessary to sift the sand and strain the clay before adding it to the solution.

If you plan to add asbestos to the putty for the stove for strength, then the fibers should be thoroughly ground. It is also worth remembering that this material requires careful use, as it poses a danger to human health.

Additives in the form of wood ash, salt, gypsum, lime and cement help increase the strength of the solution.

Ready-made putty for stoves is used if the masonry mortar was mixed on a similar basis.

How to seal on metal stoves

The problem of how to cover up cracks in a metal stove can be solved by welding. However, if this is not possible, they resort to recommendations for making putty that is resistant to high temperatures.

Aqueous solutions can be prepared from the following ingredients:

• 30 parts clay, 4 parts metal filings, 2 parts manganese dioxide, 1 part salt, 1 part borax.
• 10 parts magnesite and 3 parts liquid glass.

Drying oil-based solutions are prepared from the following components:

• 4 parts clay, 2 parts zinc white, 1 part manganese oxide.
• 12 parts graphite, 4 parts lead and 3 parts chalk.

For flawless operation of the stove, it is necessary to carefully consider not only its design features, but also choose materials that will maintain heat in the house.

It still remains a very popular method of heating private homes. Accordingly, all issues related to this process are very relevant today. Most often, the stove fails due to the presence of a large number of cracks, which make its operation unsafe, since carbon monoxide penetrates into the room through them.

Faced with such troubles, owners of private houses ask the question: “how and how to cover the stove so that it does not crack?” It is this problem that we will pay attention to in this article.

Reasons for furnace failure

Before looking for the best way to fix the problem, it is necessary to determine the causes of cracks. It could be:

Low quality of the solution used;

Violation of finishing technology;

Shrinkage of a brick structure;

Uneven heating;

Failure to comply with the rules for operating the stove.

If the stove sank due to an improperly poured foundation, smoke will pour out of all the cracks during the fire, the doors will no longer close tightly, and the brick will gradually begin to collapse. If such problems are discovered, the entire structure should be immediately disassembled, manufactured and re-laid. However, in some cases you can do without radical measures.

The fact is that a slight shrinkage of the stove in the first couple of years is considered quite normal, and if we are talking about small cracks, they can simply be repaired correctly.

All other reasons can be easily eliminated; it is only important to figure out how to cover the stove so that it does not crack.

Determining the extent of damage

Before getting started, you should consider the damage and determine the scope of work. If small cracks appear on the surface of the stove (even if in large numbers), to eliminate them you will need to remove the lining and clean the brick from the plaster.

Once all the finishing has been removed, you can start caulking the cracks. At this stage, everyone is wondering what solution to cover the stove to prevent it from cracking.

For these purposes, you can use one of the following mixtures:

Made of clay and sand;

From special grouts for ovens;

From fireclay clay;

From oven glue.

Can’t decide what to cover the stove with to prevent it from cracking? Consider each option individually.

A mixture of clay and sand

Sealing cracks with clay mortar is the simplest and most economical way to restore a stove. At the same time, the quality of repairs will be no worse than using newfangled and expensive materials.

For these purposes, you can take absolutely any clay, the main thing is that it contains as few impurities as possible. After soaking, high-quality raw materials should become oily, homogeneous and plastic. Before covering the stove with clay (to prevent the surface of the fireplace from cracking in the future), pay attention to the specifics of preparing this solution.

How to make your own clay putty

Mixing the mixture is carried out in several stages.

1. Before mixing clay with sand, it should be soaked in warm water for at least 12 hours.

2. The wet solution should be thoroughly mixed and all lumps formed should be broken up. In this state, the clay combines with sand much better.

4. If you do not plan to whiten the stove, add lime to it at the stage of mixing the solution. All components are mixed until the consistency of sour cream. The finished mixture is covered with plastic wrap and left for 12 hours.

5. The settled solution is kneaded again. To check if there is enough water in it, take the putty in your palm and roll it into a ball. If it starts to crack when you squeeze it, add more water.

6. The oven should be lightly heated, water should be poured over the cracks, after which you can begin sealing.

7. To prevent the appearance of new cracks in the clay, you can add straw, but a more reliable way is to use a plaster mesh. If you apply a clay solution to a stove lined with such material, you can forget about the cracks for a long time.

Fireclay clay

Very often, this material is used for the restoration of old stoves. This material is characterized by fire resistance, so stoves finished with its help are reliable and durable.

You can purchase this type of clay at any construction market. It is sold in 20 kg bags and is not expensive at all. The working solution is prepared strictly following the instructions on the packaging.

Grout

To seal a brick oven, you can purchase a special grout. In stores there are various formulations that are produced specifically for these purposes. It’s worth noting right away that this option will cost you quite a lot, however, it is optimal for fireplaces.

If you cannot afford to purchase a specialized composition, prepare it at home. To do this you will need the following components:

The clay needs to be thoroughly kneaded, filled with water and set aside for 12 hours. After the specified time has passed, the required amount of sand should be added to the mixture. In the process of kneading the two components, finely chopped straw and salt are gradually added to them. Clay and sand are taken in a ratio of 4:1, with about 50 kg of straw and a pack of salt added for every 4 buckets of clay.

The resulting composition can withstand temperatures of more than 1000 degrees.

Oven glue

To prevent the stove from cracking in the future, you can use it to repair it. It belongs to the category of ready-made materials for finishing fireplaces, which are sold at construction sites. Its main qualities include resistance to high temperatures and durability.

This adhesive mixture contains fireclay powder and fire-resistant types of cement. Today, there are two types of glue - plastic and hard.

The first option is used for sealing cracks, and the second is intended for plastering the entire surface of the stove.

The main advantage of oven glue is its very fast drying, so you should not mix the solution in large quantities.

Work technology

When the material for the restoration of the heating structure has already been selected, it’s time to figure out how to properly seal the stove (so that the lining and the brick itself do not crack).

The method of applying putty is selected depending on the type of solution.

So, if you decide to eliminate cracks using a homemade mixture of clay and sand, the process will not cause you any particular difficulties.

1. First, the brick is cleaned of old finishing material and plaster.

3. Now you can start sealing the holes. First, the solution must be firmly pushed into the cracks, and the residue must be spread over the surface in an even layer. The work can be done with bare hands, as this composition is absolutely harmless.

4. The final stage will be plastering the external surfaces.

Please note that you can light the stove only after the solution has completely dried!

Now let's look at how to seal the oven (to prevent it from cracking) with heat-resistant glue. This process is almost identical to the previous one, but differs in that after sealing the cracks with a plastic composition, the entire surface of the furnace is treated with solid varieties of adhesive fire-resistant mixtures.

Since the glue dries in less than 30 minutes, you can begin decorating the stove on the same day.

In this article, we looked at what and how to cover the stove so that neither the structure itself nor the lining cracks. In conclusion, I would like to note that even the best and most expensive refractory compounds are not able to protect your stove from cracks. Here the main role is played not by the quality of the material, but by strict adherence to the technology of construction and repair of the heating structure. Carry out the work thoughtfully and slowly, and then your stove will serve you for many years.