Where does the construction of any facility begin? Naturally, with laying the foundation. To create good solid foundation concrete is required. It is one of the most popular and inexpensive building materials. But the quality of the components of the concrete mixture is currently not always high, so additional components are needed to extend its service life.
In order to increase the strength of concrete, they put into the structure steel reinforcement, that is, they create the basis of reinforced concrete.
There are many ways to strengthen concrete. There are several quite worthy means on the construction market.
These are special impregnations from various foreign and domestic manufacturers.
Moreover, they are almost identical in quality. The main function of impregnations is to strengthen the concrete mixture for the floor, blind area, and foundation. Without such mixtures, the concrete base has low wear resistance, and if the coating is applied outdoors, then cracks appear due to constant temperature changes or vibration. The composition gradually crumbles, and it is almost impossible to save the coating. Such disintegration of the concrete coating also occurs if the cement itself is of poor quality or, when filling the solution, the correct proportions of the components of the concrete material are not observed.
The most effective polymer or polyurethane impregnating mixtures for strengthening concrete composition. When the top layer of the screed is filled with polymer impregnation, a new, higher quality layer of concrete polymer is formed on its surface. The quality of expected floor strength will depend entirely on how deeply the strengthening compound penetrates. The surface becomes stronger and, accordingly, the service life of the coating increases. One of the main advantages of strengthening impregnations is the ability to apply them to surfaces at air temperatures down to -30 degrees.
Application of additives
Scheme of a pilot plant for impregnation of porous concrete with liquid radioactive waste: 1-container with porous concrete; 2-probe; 3-pump; 4-pressure gauge; 5-liquid radioactive waste storage tank; 6-protective box; 7-pipeline.
- After you have purchased a reinforcing screed, you need to prepare the surface. Already applied in a standard way The concrete must be smooth and always damp. Applying impregnation to a frozen dry screed is not permissible;
- The dry strengthening mixture is applied to the wet screed in an even layer. After this, it immediately begins to interact with the surface layer of the floor. The result of these actions will be a floor covering that is resistant to chemical and mechanical influences. If the screed is located outdoors, then impregnation will protect it from exposure sun rays. In terms of aesthetic qualities, appearance the sex becomes much more attractive;
- when concrete is strengthened in production and industrial premises where the surface area to be treated is large, additional Building tools: Grinder, distribution trolley and seam cutter. They are necessary for faster processing of the wet concrete layer;
- Using a strengthening mixture, you can create room decor. Modern manufacturers take this fact into account and produce strengthening compounds of various colors. At the same time, the main technological qualities of impregnations do not decrease, but increase. Colored compounds protect any concrete covering not only from mechanical impact, but also reduce dust formation. Such mixtures are used in trading floors and in warehouses.
Types of impregnations
Currently, the most popular are impregnations made using polyurethane materials. Modern technologies make it possible to produce them for concrete pavement located in any room or outdoors.
If the basis of the future surface is soil, then screeding of concrete and floors can be carried out using impregnation for concrete grade M150-M350. This composition allows you to saturate a layer 3 mm deep. In this case, the concrete itself in the upper layer becomes similar in strength to grade M600. The surface will be more resistant to dust formation, and the base will be more airtight.
Scheme for repairing concrete defects with exposed reinforcement: a – concrete defect with exposed reinforcement; b – removal of destroyed concrete, application of a protective layer to the reinforcement; c – restored section of the structure. 1 - building construction; 2 - fittings; 3 – material “KTtron-primer”; 4 – thixotropic repair material “KTtron” (depending on the project).
The biggest advantage when using polyurethane reinforcements is their ability to increase chemical resistance concrete covering. For example, a floor with such impregnation lasts for many decades and does not require additional effort when cleaning. They are easy to clean with regular detergents.
There is another impregnation option with deeper penetration. It is intended for concrete grade M300. The composition used penetrates the floor to a depth of 5 mm. When applying this mixture, it is necessary that the ambient temperature be at least +5 degrees. Strengthening mixture deep penetration, as a rule, is used for floors with a weak layer of concrete M150. When working with this composition, for maximum hardening, the floor with already applied impregnation should be covered with a polyethylene film. In this case, the impregnation will penetrate the floors much deeper. The deep penetration impregnation technology allows it to be used for high-strength concrete bases and wet bases.
In addition to polymer impregnations, there are other varieties that are more modest in cost. This is fluate impregnation. Despite the low cost of the material, its qualities are no different from its polymer analogues. The strength of the concrete coating increases up to 50%, and the appearance of the floor does not change and is pleasing to the eye. In addition, after applying this impregnation, a film does not form on the surface of the floors. All types of strengthening mixtures can reduce dust formation in the room.
Strengthening large volumes of concrete
If the task is to strengthen a larger volume of concrete for large areas, then a complex of different modifier additives should be used. They are mainly used in the construction of large, high-strength structures to strengthen concrete. Additives are introduced into the ready-mix concrete mass. They help the concrete mass achieve strength grade M700 and higher. Wherein technical staff the bulk does not change.
So, with the help of strengthening impregnations, you will not only achieve the strength of the floor covering, but also create unique interior in your premises.
Violation of technology during construction and repair work inevitably leads to large or small troubles, which subsequently have to be eliminated, spending a lot of effort and considerable money. This axiom fully applies to incorrectly performed floor screed, as a result of which various defects. It can crumble, crack and, as builders say, buckle.
If cracks appear in the floor after screed work, then the simplest, and most importantly, inexpensive option would be to make regular repairs.
How can you repair small cracks?
Firstly, after detecting such a defect, it is necessary to carefully examine the floor and determine the root cause of the cracks. There are several reasons why this problem can occur. This is a poorly measured coating layer, rapid drying of the applied layer, problems with moisture in the solution - too much or, conversely, too little water. Forgetting to install the gasket also leads to cracks. edge tape, as well as the absence of expansion joints.
If it turns out that the cracks were due to unmade seams, it is necessary to urgently make the seams for shrinkage. The depth of such a shrinkage seam should be no less than a third of the base. They must be done in increments of up to 5 meters. The seams must be sealed with a sealant based on polyurethane.
We will find cracks, especially if they are very thin, they need to be widened, for which we can groove them. Remove any dust that has formed in the crack and prime it. Such cracks must be sealed with non-shrinking material using a regular staple. Some subtlety - if it is laid on the floor tile, and the cracks that appear on the screed are very small, then you don’t need to do anything with them. Larger cracks are sealed special composition which is easy to do with my own hands. It includes cement, PVA glue and water. The resulting mixture must have a liquid consistency so that it can be poured into the cracks formed without any problems. After the poured mortar has hardened in the cracks, you can begin all subsequent work, for example, covering the floor.
Concrete floors are characterized by high strength, durability, unpretentiousness, affordable price. But at the same time they also have weak sides. The most obvious of them is the tendency to destroy the top layer. Over time, cracks, potholes and chips appear on the surface of a concrete floor. To prevent this process, use various technologies strengthening concrete.
Basic ways to strengthen a concrete floor
Strengthening concrete floors prevents their further destruction and returns them to their previous performance properties. Exist different technologies strengthening concrete. The specific method is chosen depending on the condition and age of the floor.
Currently, to strengthen a concrete floor, the following are most often used:
- grinding;
- topping;
- special impregnations.
Topping is a relatively simple and economical technology, allowing you to obtain high-strength, dust-free floors. After applying the topping, the concrete surface becomes 5 times more wear-resistant and 2-4 times more impact-resistant. Floors with topping are recommended for use in production workshops where heavy loading equipment operates, in shopping malls, garages and parking lots. But such floors are not suitable for rooms where chemical spills are possible.
For rooms with high humidity Special impregnations that compact the structure of concrete are more suitable. They penetrate deep into the concrete, creating the effect of sealing and densifying the material. Impregnations are widely used to strengthen old and weak screeds, as they can increase their strength and resistance to abrasive loads several times.
Concrete grinding
The surface layer of a concrete floor is not very durable, so when it is exposed to mechanical loads, changes in temperature and humidity, it begins to crumble, which leads to a reduction in the life of the floor. In addition, the process of concrete maturation is always accompanied by the release of cement laitance to the surface. When hardened, this milk forms an extremely fragile layer, which often becomes the main source of the formation of cement dust. To prevent dust formation, it is necessary to remove the top weak layer of concrete and expose a stronger surface. To do this, grind the concrete floor.
Sanded floors have a number of positive qualities:
- high strength and wear resistance. Floors after sanding can withstand any increased loads well;
- chemical inertness. Sanded floors become resistant to various technical liquids and chemical solutions;
- dust-free, hygienic. After grinding, a concrete floor stops generating dust, making it easier to maintain;
- decorativeness. After grinding and subsequent polishing, concrete floors become aesthetically attractive and can be used not only in industrial areas, but also in residential areas.
There are different technologies for installing polished concrete pavement, so they can consist of a different number of stages. The number of these stages depends on many factors, including the initial state of the concrete floor, the conditions for this process, and the type of tool used.
In any case, the process includes the following main steps:
- preparatory work. At this stage concrete base cleared of debris and dust. If there is any floor covering, it must be dismantled and the surface leveled as much as possible. Next, you should repair all existing cracks and chips;
- after preparatory work perform rough grinding concrete surface. For this they use diamond tool 80 Grit;
- after rough grinding, impregnation is applied to the concrete to harden its surface;
- after the impregnation has dried, perform fine grinding, using a tool with grits from 150 to 400 Grit
- on next stage The floor is being polished. Its surface is brought to perfection by successive applications of fine-grained tools, starting from 1000 to 3000 Grit;
- floor surface after polishing cleaned of dust and coated with several layers of polyurethane varnish.
Grinding can act as an independent procedure to strengthen a concrete floor or as a preparatory stage before applying reinforcing compounds, since it increases the adhesion of the concrete surface to any construction mixtures and solutions.
Sanding is used for both freshly laid floors and old substrates.
The first pass on a freshly laid floor is made no earlier than 6-7 days after pouring the concrete mixture. This is necessary in order to remove the layer of cement laitance and open it for better ripening more durable layer. Final grinding is performed no earlier than a month later, that is, after the concrete has fully matured.
Before grinding an old concrete base, its readiness for this procedure is first assessed. “Weak” areas - looseness, peeling, crumbling - are unacceptable. If such defects are present, it is necessary to carry out repair work using epoxy compounds.
More details about repairs with epoxy mastic are described in the article Eliminating defects in a concrete floor using epoxy mastic
If the damage covers more than 30% of the floor area, a new screed is poured.
Other methods of repairing a concrete floor are described in the article Basic methods of repairing a concrete floor
Benefits of strengthening with topping
The technology of strengthening concrete floors with the help of special dry mixtures (toppings) has proven itself when used at various facilities, and therefore is now very popular. Topping can be used to strengthen a concrete surface, which will be used independently in the future, or to strengthen the base for any other floor covering. This technology involves applying a special dry mixture to freshly poured concrete concrete and its subsequent grouting using a trowel. The smoothing blades of this machine press the topping into the hardening concrete. In this case, a hardened surface layer is formed.
Concrete floors, after strengthening with topping, acquire the following advantages:
- high strength. After topping, concrete grade M400 acquires strength equal to grade M800;
- the strengthened surface acquires best performance characteristics, and caring for it becomes easier;
- concrete floors with topping stop generating dust and become highly resistant to abrasives;
- treated concrete acquires antistatic properties;
- using topping you can improve the decorative effect of a concrete floor, giving it a variety of textures: grainy, smooth, mirror-like.
Basic technical specifications floors with topping are determined by the components of the rubbed mixture. This mixture contains cement, mineral pigments and fillers.
The size of the filler fractions is selected depending on the type of concrete used to fill the floor. When choosing, you must remember that any fine filler has the least adhesion to the concrete base, so the likelihood of such topping peeling off is much higher.
The use of a larger fraction gives the floor increased strength, but greatly reduces the ductility of the mixture.
Depending on the type of filler, mixtures are divided into:
- quartz;
- corundum;
- metallized.
Quartz mixtures
Operational and technical properties quartz hardeners allow their use for floors subject to moderate wear loads. With the help of quartz toppings they strengthen floors in stores, administrative buildings, in warehouses and garages with low loads.
Concrete floors at various facilities are described in the articles below.
Polished concrete floors in parking lots and garages
Usage quartz sand as a filler, it can increase the strength of a concrete floor by one and a half times. The main advantage of quartz topping is its affordable price.
Corundum topping
Corundum hardeners are used when it is necessary to create a particularly stable concrete floor subject to high loads. Floors reinforced with a corundum mixture can be exposed to increased abrasive and shock loads, but at the same time cracks and other damage will not appear on them.
Corundum chips, used as one of the components of the strengthening mixture, give the floors special strength. With the help of corundum topping, the strength of a concrete floor can be increased by 1.7 times. But compared to a quartz mixture, corundum is more expensive. The price difference is approximately 20-30%.
Metallized topping
Metal shavings are used as a filler for this topping, which gives it special strength. Metallized topping is recommended for use on floors that experience increased loads. These could be floors in workshops industrial enterprises where heavy loaders are used or in garages designed for heavy equipment.
But it should be borne in mind that metallized mixtures cannot be used in rooms with high humidity, since a floor with such a topping will quickly become unusable due to the rusted metal component. The floor screed for metal topping must be cast from concrete of a grade not lower than M300. Otherwise, the concrete base will quickly crack.
More details about the technology of applying topping are described in the article Technology of applying topping
Strengthening concrete with impregnations
Concrete impregnations are one of the most common ways to strengthen concrete floors. They represent liquid composition on an organic or inorganic basis. Inorganic impregnations are called fluates. After application they enter into chemical reaction with concrete components. As a result of this reaction, a strong protective film from chemically inactive compounds.
Organic (polymer) impregnations are considered a more effective material for strengthening concrete. When using them, the pores of the top layer of concrete are filled with polymer, so it is modified into a concrete polymer with improved strength characteristics. Moreover, the degree of strength obtained will largely depend on how deep polymer composition penetrated into the concrete thickness.
Unlike topping, impregnations should be applied to concrete no earlier than 10-15 days after it is poured. Before applying the impregnation, the floor surface must be thoroughly cleaned and sanded to remove the layer of cement laitance.
Main types of impregnations for concrete
All strengthening impregnations available today are divided into:
- impregnating compositions-fluates;
- polyurethane;
- deep penetration.
At the moment, the most popular are polyurethane impregnations. The high demand for impregnations of this type is explained by the fact that they allow not only to strengthen concrete, but also to create additional tightness, protection from dust, and increase immunity to temperature changes and various chemicals. The depth of the reinforcing layer reaches about 3 mm.
The main limitation on the use of polyurethane impregnation is the moisture content of concrete: it should be no more than 5%.
In cases where it is necessary to strengthen the concrete coating as much as possible, deep penetration impregnations are used. These compounds give concrete floors specifications, identical to those they acquire using materials of the first group, but only the latter can be used in rooms with high humidity.
As a result of treatment with deep penetration impregnations, the strengthening layer is 5 mm.
Impregnating fluate compounds are the cheapest materials for strengthening concrete. With their help, you can strengthen the concrete base by at least 50%. The main advantage of using fluates is their low cost.
Depending on the method of action, film and penetrating impregnations are distinguished.
- The first form on the floor surface protective layer, but do not strengthen loose foundations.
- Penetrating, on the contrary, reacts with concrete and holds unstable surfaces together.
Penetrating compounds can be used at low temperatures. Their main advantage is relative savings: film impregnations must be periodically renewed, while penetrating ones are applied once.
But it should be noted that the use of penetrating impregnations is useless on screeds made of low grades of concrete and on cement-sand bases. These hardeners will not give the desired effect in this situation. For this reason, film compositions are more in demand.
Film strengthening compounds are divided into:
- acrylic film coatings that are used to protect concrete floors exposed to light and medium loads. Floors impregnated acrylic compounds, can be used without repair for no more than 3 years. After this period, the layer must be updated. Main advantages acrylic impregnations– relative cheapness and ease of application;
- epoxy impregnations allow you to protect the concrete floor from strong abrasive and chemical loads, as well as seal a fairly loose surface;
- polyurethane mixtures are used for maximum loads on a concrete floor. These compounds provide optimal protection in wet areas and can extend the life of the floor by 4-5 times.
Flat floor – required condition when renovating an apartment. It is important to keep it in good condition even after repairs. If the floor has undergone deformation, it is necessary to find out and eliminate its cause and repair the floor screed.
Peculiarities
The floor screed, even if it was made exactly in accordance with the correct instructions, becomes unusable over time. This is not surprising, because it experiences enormous loads from the weight of flooring, furniture, people’s movement and other dynamic influences. Therefore, to avoid complete loss of its operational properties, it is necessary to periodically repair the floor screed.
To get an idea of the degree of surface deformation, you must first completely remove the old coating and clean the floor of debris, dust and dirt. Next, you need to decide on the type of deformation and repair that will need to be done.
One of the following may happen:
- The smooth surface has small pits and a few cracks, and the level of dust formation is increased. These damages are not terrible; they can be easily repaired with minimal loss of time and money.
- The screed is peeling off, the surface is cracked quite deeply in selected places. This type of deformation can be repaired, but it will be necessary to use special building mixtures.
- The surface is significantly curved, the floor is covered with deep cracks. Repairing damage of this magnitude can only be done by professionals with the appropriate skills and techniques.
Before you begin repairs, you should pay attention to some procedures that will tell you which method of eliminating defects is suitable in each specific case. Necessary:
- identify the cause of deformation;
- identify the presence or absence of expansion joints (if there are none, then it is necessary to start laying);
- determine the filling method cement mixture and the type of base on which the floor was laid;
- find out whether concrete is peeling by tapping the surface with a hammer.
Types of damage
Before starting floor screed repairs, it is necessary to determine the type of damage. This can be done by removing the floor covering. A visual assessment of defects will help identify a specific type of damage, which will allow you to quickly select necessary funds and start repairs.
The main types of damage include:
- detachment of the screed (in whole or in part) from the base of the floor;
- unevenness, potholes, cracks and holes on the surface;
- excessive dust formation, which means weakening of the screed material.
The reasons for the appearance of defects can be very diverse. It is necessary to pay special attention to them in order to avoid similar mistakes and further destruction of the screed in the future.
The most common reasons are:
- Violation of mixing technology. Most often this happens when using a ready-made mixture. It is recommended to strictly follow the manufacturer's instructions, as incorrect proportions will lead to deterioration in the quality of the mixture. Also, you should not mix the solution by hand - for this purpose it is better to use a special attachment on electric drill or construction mixer so that the existing substances are mixed evenly.
- Fast drying. When working with concrete, you should always remember that its durability and strength directly depend on contact with water. The cement floor should not dry too quickly; it should be periodically sprayed with a small amount of water and covered with polyethylene to upper layer does not become dry before the concrete has completely hardened.
- Excessive amount of water in solution. Excess water in the concrete mixture, firstly, deforms the concrete itself and reduces the strength of the screed. Too much a large number of water ultimately leads to the screed cracking and the surface becoming loose. To avoid this, after the concrete has dried, the screed must be covered with deep penetration soil, which will entail new costs and increase the repair period.
Most often, defects appear in the cement screed; when using semi-dry mixtures and gypsum compositions, the likelihood of cracking is significantly reduced.
- No expansion joints. Incorrectly routed expansion joints or their complete absence most often causes the surface to crack. It is recommended to fill the wall seam with an elastic material like polypropylene foam. It is located along the thickness of the screed, and this reduces the influence of the wall load on it. Intermediate seams divide the screed into equal parts, running along half of its thickness.
- Lack of damper tape. It is especially important to have an edge tape when pouring screed for heated floors. When heated, concrete tends to expand, thereby creating additional pressure on the walls. Thus, the absence of a pressure-compensating tape can cause the destruction of not only the screed, but also the walls themselves.
- Poor quality reinforcement. The main rule when installing reinforcement is its location in the concrete, and not under the screed.
There are many other factors that lead to the destruction of the screed. Most often, this is poor quality of the solution, low-quality cement mixture used in construction, or violation of the pouring stages. Detachment of the screed can be caused by local impact loads or improper preparation of the surface for pouring concrete.
Whatever the error, you should not ignore the detected deformation of the screed. Minor repairs on initial stage destruction will keep the floor intact and save a significant amount on its subsequent restoration.
How to repair cracks?
The types of deformation described above lead to the screed starting to crack. This is bad because over time even the smallest depressions expand, and because of them you will have to make major renovation floor. Cracks are one of the most severe types of destruction, requiring emergency removal, so they must be eliminated in a timely manner. Cracks can be small and deep.
You can repair the screed yourself as follows:
- Use a grinder to widen and deepen the crack. Special attention It should be noted that after expansion, the edges of the crack should not crumble, but should be absolutely solid. If you can’t use a grinder, you need to stock up on a hammer and chisel.
- After expansion, the cracks need to be cleaned. Only a construction vacuum cleaner is used for this purpose.
- The cleaned areas are coated with epoxy primer. This must be done several times until the mixture is completely absorbed into the concrete.
- After the primer has completely dried, the damaged areas are filled with a mixture of Rizopox 3500 and quartz sand. The mixture should fill the crack just above the surface level.
- After the mixture has hardened, the repaired areas are sanded and cleaned.
To seal very small cracks, you can refuse to purchase ready-made mixtures and use the usual tile adhesive or mixture for self-leveling floor. However, it must be taken into account that this method is unacceptable when repairing screeds in rooms with high humidity.
Repairing minor damage takes little time and allows you to do without special tools.
If large cracks have formed in the screed - more than 2 mm in width - the repair process will proceed according to the following scheme:
- As in the first case, the cracks must be cut to their full depth.
- After expanding the crack across it, it is necessary to make several grooves.
- Small repair seams (1.5 cm long) are made along the grooves at intervals of 2 cm.
- The prepared recesses should be cleaned using construction vacuum cleaner, primer and leave to dry.
- After the primer has dried, the repair joints will need to be filled with pieces of reinforcement, metal staples or wire.
- Next, the cavities are filled with liquid mortar from a mixture of sand and cement. The surface is leveled with a lath and sanded after drying.
Reinforcing the screed helps protect it from stress and extends its service life. There is also a little trick that will help you find out whether the cracks are expanding over time or not. To do this, you need to glue a paper strip to the edges; if it breaks after a while, then the forecasts are disappointing. If the piece of paper remains the same as it was, then everything is in order. But this method requires a lot of time.
Elimination of peeling
As mentioned above, the reason for concrete peeling in some places is the uneven distribution of loads. You can identify exactly where the areas affected by mechanical stress are located by hearing. To do this, it is best to arm yourself with a small hammer and gently tap the entire surface. IN repair work those places where the sound will be dull are needed, especially if they are marked with cracks and the concrete begins to crumble.
Elimination of peeling occurs as follows:
- After identifying areas in need of repair, you need to highlight their boundaries using chalk or a marker.
- Inside the damaged area, holes with a diameter of no more than 20 mm must be made in the screed. The distance between the holes should be 25-30 cm.
- The epoxy solution is brought to a liquid consistency, after which it is poured into a construction syringe.
- Using a syringe, the solution must be poured into the holes. The essence of this method is that the composition will displace the accumulated material between the concrete and the base. air mass, will fill the space and connect the screed and the ceiling to each other.
If the air does not come out of the cavity completely the first time, the procedure must be repeated.
A day after it is carried out, you should make sure that the entire surface has been reanimated. If this operation was successful, you can begin laying the floor covering. Make sure the solution is completely dry. To speed things up, you can use a hair dryer.
It is very important to remember: if at the diagnostic stage it was revealed that more than 1/3 of the area has peeled off, then the screed will have to be completely dismantled, since similar works to strengthen in in this case won't help.
How to strengthen?
Strengthening weak tie- this is the way preventive maintenance. Carrying out some simple manipulations will eliminate the need to remove the screed to the base, and will also protect it from destruction and delay the need for urgent repairs.
If the floor screed is not made correctly, then over time it can collapse: crumble, crack, buckle. In this case, there is no need to redo it.
You can simply repair the screed, which will be a more economical option.
When cracks appear in the floor screed, it is necessary to initially determine the cause of their appearance, and then begin to eliminate them.
The reasons for the appearance of cracks in a cement screed may be an incorrect coating layer, rapid drying, excess or lack of water in the solution, lack of edge tape or expansion joints.
If the floor screed is cracked due to the lack of expansion joints, then it is necessary to cut through the shrinkage joints.
In this case, the depth of the cut should be at least one third of the thickness of the base. The distance between the seams should be within 5 meters. Seams are sealed using polyurethane-based sealant.
When cracks appear in them, you can make a groove, thus expanding it. It is necessary to remove dust from the walls of the groove and prime them. To seal cracks in the floor screed, it is necessary to use a non-shrinking substance, which is applied with a spatula.
If the cracks on the floor screed are insignificant, and floor covering there will be tiles, then you can ignore them.
Cracks in the floor screed must be sealed with a mixture of PVA glue, cement and water. All these components are mixed so that the mixture can be poured into the gap. After this, the solution must be allowed to harden and the installation of the floor covering can begin.
The floor screed has burst - what to do?
If the floor screed bursts, then mandatory This defect must be corrected before laying the flooring.
If the concrete mixture is poorly compacted, air cavities may appear in the screed, which cause cracks to appear. In this case, it is necessary to remove the screed to the cavity and fill it with solution.
In order to see the cavities, it is necessary to widen the crack. If you find it, then use a pick to knock out the solution. The walls of the resulting hole must be primed and then sealed with cement mortar.
The composition of the cement mixture, which is prepared for sealing the cavity, should include one part sand and three cements. Before pouring the mixture, the concrete must be wetted with water.
The compaction of the mortar after pouring must be compacted using the piercing method. A metal rod is used for this purpose.
After repairing the floor screed, it is necessary to ensure not too much high temperature in room. To prevent cracks from appearing on it, it is necessary to periodically moisten the place where the cement mixture is laid with water.
The screed is leaking - what to do?
If the floor screed coils, then it is made poorly. The reason for the coiling of the screed may be a poor-quality mixture for the screed, a lack of primer on the base, a dirty and dusty base that is used for the screed, etc.
In this case, it is necessary to hit the screed with the blunt edge of a hammer. If the mixture is of poor quality, then a dent will remain at the impact site. The screed may buckle in the presence of cracks or in their absence.
If the screed coils in the presence of cracks, then you can try to eliminate it. To do this, it is necessary to widen the crack. Next, the preparation is very liquid solution from sand and cement.
It would be best to add PVA glue to this solution. Next, the resulting solution is slowly poured into the expanded mixture. It is necessary to pour the solution in small quantities, allowing it to dry in parts.
If this method does not remove the coiling of the screed, then it must be completely removed and refilled. This is a rather expensive option. That is why it is necessary to carry out the screed according to strictly established rules.
Also watch a useful video with expert advice on screed repair: