Floor screed repair with tile adhesive. Cracked floor screed and what to do about it? Like most people do

If the rules for pouring a concrete screed are not followed, numerous defects appear on the coating. Repairing the floor screed helps prevent further damage to the integrity of the rough base. The article will consider do-it-yourself floor screed repair, as well as the main types of defects, effective methods their elimination, recommendations for laying concrete mortar.

Causes of defects

Why does the floor screed crack? In fact, there are plenty of reasons for the appearance of flaws on a rough foundation. As practice shows, cracks, dents and potholes can occur even in the case of professional pouring of the solution. What is it connected with? It should be noted that defects in most cases appear after the installation of the cement screed. When laying semi-dry and gypsum mixtures cracking of the coating occurs much less frequently.

Peaks and troughs in the coating inevitably appear after the installation and dismantling of beacons. The reason for the formation of flaws lies in physical and mechanical properties the solution itself. The cement mixture has low plasticity, adhesion and a fairly high coefficient of linear expansion. Therefore, even if a little time passes between the installation and dismantling of beacons, this inevitably leads to the appearance of small holes and cracks.

What are the main reasons for the formation of defects in the screed?

• Incorrect mixing of the solution, in which the concentration of water becomes too high;
• Rapid (forced) drying of the coating;
• Uneven drying of the screed along the perimeter;
• The absence of a membrane base (polyethylene) under the solution;
• The presence of high temperature drops and drafts;
• Pouring too thin a layer of mortar;
• Direct connection cement mixture to the wall and communications;
• The use of a fine-grained mixture unsuitable for pouring the solution;
• Absence or non-compliance with the prescribed distances for expansion joints.

The reasons for the appearance of flaws on the draft base are varied and are not limited to the list presented. The quality of the concrete pavement can also be affected by:

1. Improper laying of heat and waterproofing;
2. Poor quality cement mixture;
3. Heterogeneity of the prepared solution;
4. Lack of necessary tools for pouring and leveling concrete;
5. Non-observance of proportions in the process of preparing the working composition.

Floor screed repair is a responsible event that requires strict adherence to the rules for the restoration of an old and freshly poured screed. To repair the base without any problems, before performing the procedure, you should pay attention to the following nuances:

1. First you need to accurately find out the cause of the formation of flaws;
2. Check if there are expansion joints on the coating;
3. Find out how the cement mixture was poured, on what basis the mortar was laid (concrete, wooden);
4. If there are no expansion joints on the floor, before repairing cracks and potholes, it is advisable to take care of their laying;
5. To determine if there is a localized delamination of the concrete, it is advisable to tap the coating with a rubber mallet.

If you ignore all of the above recommendations, after a couple of months, potholes, dents and “slamming” concrete will appear on the base again. You can learn more about how to eliminate flaws on a cement screed from the video clip.

Main types of defects

When repairing an apartment, many masters are faced with such a problem as a violation of the integrity of the screed. If we take into account that when pouring a concrete mixture, it is almost impossible to achieve uniform drying of the solution, the risk of flaws increases significantly. How to repair the coating in this case?

First of all, it is worth deciding on the type of deformation. The method of eliminating defects will also depend on the degree of damage to the concrete floor:

• Microcracks up to 15 mm in size. Occur in case of uneven drying of the coating. If there are few cracks on the surface, you can use tile adhesive to putty them;
• Large crack, 2 cm. Such types of damage often occur against the background of the absence of expansion joints and mechanical impact. When repairing apartments, it is not recommended to use caustic compounds, therefore, sealing glue or cement mortar is often used to eliminate crevices;
• "Thundering" concrete. The mobility of the concrete floor is due to air pockets under the coating. If it becomes necessary to seal the swollen areas, the exfoliated concrete is cleaned off, and the resulting potholes are filled with cement mortar;
• Local irregularities up to 5 mm high. The bulges are simply cleaned with a grinder, and small dents are filled with tile adhesive or mortar with M300 or M500 cement;
• Pits and potholes larger than 15 mm. It is quite difficult to repair numerous damages locally. Therefore, in this case, experts recommend pouring a new screed with a small layer thickness - up to 4 cm.

Apartment renovation is a problem for most home craftsmen. In the process of laying the concrete mixture, it is very difficult to prevent drafts. But it is they who in most cases become the cause of uneven drying of the base. And in order to make a high-quality restoration of the apartment floor, you need to use solutions and adhesives with good adhesive performance.

expansion joints

You need to understand that the repair of the floor screed should begin with the elimination of the causes that caused the problem. If cracks have formed on the coating, and you assume that the reason lies in the absence of expansion joints, first of all, they need to be done.

So, in order to properly make expansion joints, you should:

1. Make in concrete base recesses at a distance of approximately 5 m from each other;
2. Then, in the resulting crack, make a strobe to expand the gap to 2 cm;
3. After that, prime the crack and fill it with non-shrinking adhesive;
4. Once the glue has hardened, remove the excess with sandpaper.

You can see how to make expansion joints in the video below. When repairing an apartment, experts recommend that the rooms being renovated be well ventilated, since non-shrink compositions may contain harmful volatile substances.

Is the crack widening?

The cement mixture itself is very susceptible to flaws. At the same time, it is very important to find out not only the cause of their formation, but also the dynamics of the increase in crevices in the screed. In particular, this practice applies to apartments in which interfloor ceilings are not particularly rigid. How to understand if there is a tendency for a crack to increase in the base?

When checking the coating for the possibility of further deformation, you need to do the following:

1. Stick a strip of paper on the crack;
2. Do not touch the glued area for a month;
3. If after a specified period of time the paper breaks, we can talk about a trend towards an increase in the size of the crack.

What to do in this case? Often these problems arise when self repair apartments. Why? Failure to comply with the rules for mixing and laying concrete mortar inevitably leads to material damage. To correct the situation, it is advisable to seek help from specialists. Of course, the price for subfloor restoration can be quite high. But in this case, you can be sure of the quality of the work done.

Elimination of minor defects

Doing the restoration of the screed with your own hands in the presence of small cracks is quite easy, for this you need:

1. Using an angle grinder with a diamond disc, widen the crevice a little;
2. Remove loose pieces of concrete along the edge of the crevice;
3. Prime the resulting cracks;
4. Fill cracks with tile adhesive.

Renovating an apartment comes with some challenges that are worth mentioning. If the concrete surface is cracked in the bathroom, it is impossible to repair the defects with ordinary tile adhesive. After a couple of months, it will peel off due to the high humidity in the room. If the microclimate in the room is specific, a mixture with water-repellent properties should be used to putty the flaws. You can see how to repair the screed in the bathroom in the video clip below.

Repair of large cracks

Repair of an old screed with large cracks in terms of execution technique differs little from the previous version. And yet, in this case, a mixture of cement and epoxy is used to putty the crevices. It is impossible to seal large defects with tile adhesive due to the low adhesion of the adhesive solution. What to do if the screed is cracked?

One of the main tasks of repairing an apartment is getting a flat floor. Whatever the outer coating, it is impossible to solve this problem if you do not carry out. Only with a high-quality screed will the floors look perfect.

The floor screed, like any coating, requires repair, which must be done in a timely manner so that it does not need to be completely replaced.

Self-repair of floor screed is not very challenging task, but will require the application of certain physical efforts and will require material costs. These inconveniences should not stop the owner. Any coatings age over time and become covered with obvious and hidden defects, but it is much more profitable to make a timely partial repair than a complete replacement of the screed with increased destruction.

What is the role of coverage?

In any room between the finish flooring and floor slabs there is a floor screed. It is usually made of concrete mortar of various thicknesses. AT modern designs a special mixture for self-leveling floor is used. The floor screed itself is hidden under the floor covering and therefore it may seem that it is not subject to destruction. However, in fact, the main task of the concrete pavement is to take on the main mechanical load acting on the floor. It is a damping layer for overlapping. Constant mechanical load, of course, leads to the gradual destruction of the floor screed material.

An important role of the screed is that it levels the surface and thus ensures horizontality and evenness. outer coating floor and increases its durability. Besides, concrete pavement designed to hide various communications: electrical wiring, pipes, floor heating, etc. Finally, the screed is an additional layer that provides thermal and sound insulation. The role that the coating plays in ensuring the quality and reliability of the floor is enormous, so it is so necessary to independently monitor its condition and ensure its performance.

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Types of floor screed damage

Under the influence of various loads or due to poor-quality workmanship, the floor screed is destroyed. When removing the top flooring, all the defects that have arisen become visible and can be assessed by the possibility of repairing the floor with your own hands. The main types of damage to the screed include: the occurrence of noticeable cracks or potholes, flaking of concrete from floor slabs in some areas with the appearance of air gaps, small cracking, peeling or the appearance of small shells and holes on the surface of the screed.

cracks and sometimes large cracks, are formed due to uneven or impact loads, as well as due to violations during construction: lack of shrinkage joints, insufficient reinforcement or poor-quality concrete pouring. Such damage is very dangerous due to its tendency to increase the size and number of cracks. When removing the floor covering, these defects are visible to the naked eye.

Potholes and large shells appear in areas of local powerful loads (for example, vibration of household equipment) or in places where a void appeared in the concrete during pouring. Delamination of concrete from the ceiling can occur with uneven loads or poor surface preparation before pouring concrete. Such damage is imperceptible from the outside and can be determined by a dull sound when tapped with a hammer. Poor-quality concrete or violations of pouring regimes are the cause of multiple surface damage, which manifests itself in the form of peeling of the screed surface, its heavy dusting or small cobweb cracks.

All the considered types of damage can be repaired by do-it-yourself floor screed in certain areas. The only condition for the expediency of its implementation is the disadvantage if more than 35% of the surface of the screed is damaged. In this case, it is recommended to completely replace the screed.

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Small cracks and their repair

Small cracks in the screed can be covered with ordinary concrete mortar.

Repair of small visible cracks in is carried out in the following order. With the help of a chisel, the crack expands and deepens by 10-15 mm. The vacuum cleaner carefully cleans the crack and the area around it from dust. A solution of epoxy primer in a solvent (proportion 1:10) is applied to the surface of the crack and dried. This surface treatment improves the adhesion of the grout to the crack surface. After that, a solution is poured into the crack or slot, which is a special mixture for screeding the self-leveling floor. The dried area is polished.

Small cracks in the screed can usually be repaired using cheaper conventional primers and plaster mixtures cement based. However, such repairs are likely to be short-lived, as the cause of the previous damage remains. The use of mixtures on an epoxy or other adhesive synthetic basis significantly strengthens the dangerous area and allows you to neutralize the source of cracking.

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Repair of large cracks

Large and deep cracks in the floor screed are also subject to repair. To do this, cracks with the help of a grinder expand and deepen to the floor slab or to a depth of at least 50 mm. Grooves are filled in the cracks on the side surfaces. The extended crack is thoroughly cleaned of dirt and dust. Along the crack, grooves 15-20 cm long and 20 mm deep are punched perpendicular to it. The distance between the grooves is set to 20-30 mm. The vacuum cleaner carefully cleans the crack and the adjacent area. Just as in the case of small cracks, the entire area of ​​a large crack is treated with a primer solution.

Large cracks are sealed with a mixture for self-leveling floor screed or a special epoxy mortar for concrete (for example, Rizopoks-3500 brand) filled with quartz sand. The filling of the crack is carried out in two stages. First, the crack is filled to the depth of the beginning of the grooves. Metal brackets are installed in the transverse grooves in a vertical position. The final pouring of the solution into the crack is carried out after the first layer has dried and the metal staples have been fixed in it. When repairing particularly deep cracks, the mortar can be poured in three stages. At the end of the drying of the screed repair area, all irregularities are eliminated by stripping and grinding. Doing this with your own hands allows you to reinforce the dangerous area with metal elements, which eliminates the risk of re-formation of cracks or crevices.

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Repair of potholes and surface sinks

A pothole in the screed can be repaired with a special resin-based sealant.

Potholes on the surface of the coating can occupy a significant area. Do-it-yourself screed repair in this case is carried out in several stages. First, with the help of a grinder, cuts are made along the perimeter of the pothole with a depth of 2 cm more than the depth of the pothole. If the depth of the pothole is large, cuts are made to the base. Then, using a perforator, the screed concrete is removed inside the marked perimeter to the depth of the cut. The formed recess is thoroughly cleaned of concrete residues and dust with a vacuum cleaner.

At the next stage, the bottom and walls of the recess are covered with a primer. After it hardens, it is poured with repair mortar in several layers. The thickness of each layer is usually chosen within 20 mm. Each layer is poured after the previous one has hardened. At large areas repair, it is advisable to reinforce the repaired area with metal rods, mesh or synthetic threads. After the top layer of the solution has completely solidified, the entire repair area is cleaned and polished so that its surface is strictly flush with the surface of the floor screed.

With the course of operation, the strength of the concrete floor screed decreases, which leads to the formation of potholes, irregularities, cracks. There may be problems in the area of ​​\u200b\u200bseams, increased dust formation. as a result of the development of damage, communications of the underground can be seriously affected.

Reasons for the destruction of the concrete floor:

• heaving of the subgrade. The risk of cracking increases if the screed is located in an unheated room. Such problems arise due to poor soil preparation - insufficient compaction, non-compliance with the level of the aquifer, lack or marriage of waterproofing. In this case, it is carried out overhaul, with the elimination of all causes of defects and the construction of a new structure;
• lack of care at the stage of maturation of the flooded solution. This leads to the development of shrinkage stresses, causing delamination and cracking. Delaminations also occur due to illiterate preparation of the base. During repairs, materials that provide compensatory shrinkage are often used;
• old screeds that could not withstand the actual load, action chemical substances and so on. If the number of defects is small, a set of measures is implemented to remove dust, repair potholes, cracks, and harden with polymer or chemical compositions. If the problems are global, the coating will not be able to withstand operational loads and the screed is changed to a new one.

If there are areas with exposed reinforcement on the surface, the metal is cleaned and anti-corrosion protection is applied.

Technology and materials are selected based on the actual state of the surface, operational loads. It is difficult to talk about standard schemes - it all depends on the type of object, design requirements, financial costs. An instrumental examination of the old screed may be required. However, the set of measures can be divided into complex and local.

Local repair. The work is carried out against the background of individual destruction of the concrete screed. In areas of damage, technological patches are arranged, including along cracks, potholes, and seams. The elimination of irregularities, destruction of the upper layer is being implemented, if necessary, a change of communications is carried out.

Complex repair. It is carried out during long-term operation of the premises, during the complete reconstruction of the concrete screed against the background of a large amount of destruction. During the repair, all defects are completely eliminated, alignment, hardening, and restoration are carried out. It implies the application of finishing coatings.

Concrete screed repair and preparatory measures

If we talk about major repairs, the old worn-out structure is being dismantled. The coating can be removed mechanically, resorting to the use of pneumatic chippers, picks, concrete breakers. All sludge is removed and taken out of the work site.

If dismantling can be avoided, the base is cleaned of mold, rust, remnants of old coatings. To do this, the floor is protected with metal brushes, sandblasted or treated with water under pressure.

Paint stains and greasy dirt are removed by chemical treatment (solvents).

Elimination of potholes

Potholes are the result of a violation of the installation technology and the action of high mechanical loads. Damage of this type requires immediate repair to prevent further structural failure.

Working principle:

• the pothole is embroidered with a diamond cutter around the perimeter. The depth of cut depends on the size of the defect, but usually 20 mm is sufficient;
• a puncher and an improvised tool remove damaged concrete from the disturbed area;
• sludge is removed with brushes, dust - with industrial vacuum cleaners or pressurized water;
• the excavation is covered with soil. Epoxy primers work well. The material is applied with brushes in 1-2 technological approaches;
• prepare the repair composition and fill the defect. If the depth of the pothole exceeds 5 cm, the repair mixture is laid in layers, observing the drying time of each layer;
• the mixture is leveled with a rule or a rail flush with the surface of the screed;
• when the material gains strength, the floor is polished.

Large potholes require formwork and reinforcement

Pothole repair materials:

• cement dry mixes;
• thixotropic mixtures;
• epoxy, polyurethane compounds.

Crack repair

With the repair of cracks, it is better not to delay. Otherwise, the gap will grow, liquid and debris will get into it, coloring of the layers is not excluded. In addition, it is easier to repair the smallest defects. Sewing is required first. If the crack has not gone deeper than 20 mm, a 10 mm recess is cut with a cutter. If the defect is deeper - 50 mm. For long and large cracks, special channels are developed on both sides and the recess is deepened.

Cleaning of dust and sludge is carried out in a standard way. Next, the surface is coated with polyurethane or epoxy primer. The material is recommended to be pre-diluted with a solvent in a ratio of 1:10. Next, a repair compound is prepared based on polyurethane, epoxy polymers and quartz sand.

The mixture is laid in layers, after drying, grinding is carried out. For large defects, they act differently - wide cracks are fixed with steel brackets. For staples with a step of 25 cm, recesses are cut 1.5 cm wide, 2.0 cm deep. A repair compound is introduced into the slot, reinforcement is laid, the repair material is laid on top again.

Crack repair materials:

• dry cement mixtures;
• polymer compositions;
• thixotropic compounds.

How to get rid of bumps

Irregularities in the concrete screed adversely affect the quality of the finish coating. For alignment, a milling machine is used. Depth of processing - 1 cm. After milling, the floor should be sanded. Rack control required.

When the work is completed and there is no doubt about the evenness of the screed, the surface is impregnated with p / y or epoxy primersdiluted with a solvent. Any thin-layer coating is applied to the screed, leveled with a rail. After the solution has matured, the floor is polished.

Materials for leveling concrete screed:

• bulk repair mixtures;
• concrete mixtures for spray application.

Seam repair

Expansion joints are the weak point of any concrete screed.. During operation, they lose their original strength and begin to crumble. First of all, the gaps are embroidered with diamond disks. The cut should be perpendicular to the floor.

After work, sludge and debris are removed, for which industrial vacuum cleaners and sandblasting machines are traditionally used.

Metal markers are installed along the seam in increments of 2.5-3 cm. The seam is filled with a repair compound. When the material gains strength, grinding is carried out. The markers are dismantled. According to the remaining markup, a new one is cut out expansion joint. After thorough cleaning of the cavity and priming, an elastic cushioning cord is placed in the recess. which will provide resistance to water and vibration loads. From above, the gap is filled with sealant or mastics.

Seam Repair Materials:

• sealants;
• mastics (cold and hot);
• elastic pads;
• sealing tapes.

Filling voids by injection

When the screed peels off from the base, the resulting voids reduce the wear resistance of the structure. Such defects can be eliminated using the injection technique. The surface is tapped with a hammer, which makes it possible to reveal the location of the voids. Where the delamination has occurred, the tool will make a dull sound.

After determining the contours of the delamination areas, holes with a diameter of 16 mm are drilled along them.. The installation step is 25 cm. A low-viscosity repair compound is poured into the holes using a special syringe. The filling of the recess is carried out gradually, but the composition must fill the entire cavity. After 24 hours, you can deal with the installation of a protective coating.

Dedusting

Dusting is no less common problem with concrete floors than cracks and potholes. But, modern techniques make it possible to carry out repairs in such a way that complete dust removal is achieved, the strength and wear resistance of the structure increase. Three technologies work in this direction: topping systems, polishing / grinding, processing with special impregnations.

Application of grinding and polishing technologies

At large volume processing is carried out with the participation of professional mosaic-grinding machines and trowels. The operation is started 5-7 days after pouring the screed. So the concrete will gain the required strength and it will be possible to completely remove the layer of cement laitance. The second grinding is carried out after the complete maturation of the structure - on average, for 28 days. This is the solution for a screed overhaul.

If the structure is in satisfactory condition, grinding is carried out on the old basis with a mandatory assessment of its readiness for such processing. If there are loose, crumbling, flaking areas on the screed, they are cleaned off and repaired with epoxy compounds.

If the old screed does not contain serious damage, it is enough to process it with a cutter before grinding to a depth of 5-7 mm.

Grinding is implemented in the following order:

• primary processing is carried out with discs with a grain size of 30-40 units;
• it is necessary to remove the remains of old varnishes, bituminous coatings, areas with corrosion, a loose layer of cement laitance;
• when the maximum naked filler is realized preliminary alignment and application of hardening impregnations;
• finishing grinding is started after the polymerization of the coating. If you work on a fresh screed - 30 days after laying. Segments with a grain size of 100-400 units are used. and higher.

Such a concrete screed is no longer dusty, has high-strength characteristics, is smooth and even. The floor can be used for its intended purpose. If necessary, start polishing, which will increase resistance to water, chemicals and give a mirror shine.

The concrete is polished with discs with a grain size of 1500-3000 units. The choice of working body is based on the required degree of gloss (satin, crystal, etc.).

Dedusting with impregnations

Impregnations are applied after grinding. They work on concrete with inorganic lithium or sodium compounds or organic (acrylic, polyurethane, epoxy). Immediately before application, the surface is dedusted, washed with water.

Impregnations are applied to the base with brushes, rollers or doctor blades. The material must lie on the floor evenly, without dry or excessively moist areas. If the screed is characterized by a weak bearing capacity, the application precedes the priming operation.

After the layer has completely dried, you can start applying top coats.

Overhaul of concrete screed

If the damage exceeds 30%, a complete replacement of the structure is carried out. The old screed is removed.

Screed thickness calculation. The calculation is always carried out from the bottom up, providing for a margin in a big way.

The traditional design, taking into account thicknesses, looks like this:

• waterproofing (p / e film) - 1 mm;
• thermal insulation (expanded clay bedding, mineral wool, expanded polystyrene slabs) - from 25 mm;
• reinforcing mesh - 6 mm;
• protective layer of concrete - depends on the loads;
• finish coating.

Screed markers

The solution is leveled on rack or pin markers. Both types are fixed with a small amount of cement-sand mortar. The pins are laid in the corners and along the wall structures with a step of 0.5 m. Profiles - parallel to each other, the first with an indent of 25-30 cm, then - with a step of 1-1-.5 m.

Height marks on the pins are carried out with a tightly stretched cord and level

They start working from the corner closest to the doorway - diagonally. The second diagonal is beaten off along the primary cord. Next - pull them around the perimeter, make marks on the wall markers.

Screed overhaul procedure:

• the base is cleaned of sludge, debris, including together with special mixtures for cleaning concrete;
• the surface is treated with a concrete finishing machine, dedusted industrial vacuum cleaner. Apply to the entire area primer composition, you can use already familiar p / y or epoxy primer;
• waterproofing is laid on the dried layer (overlap 15 cm, entry onto the walls to the height of the screed + 2-3 cm). The joints are glued with adhesive tape;
• thermal insulation is provided. Expanded clay is poured, leveling it with a rolling roller. Or, mineral wool or expanded polystyrene slabs are tightly laid with a run-out of seams;
• laying of reinforcing mesh. The material should recede from the walls by 3-4 cm, overlap - 1-2 cells. The mesh is fixed into a single structure with a knitting wire;
• markers are attached to the surface. If pins are used, when the solution solidifies, the heights are beaten;
• prepare a viscous cement-sand mortar in a ratio of 1: 3 and pour between the markers. Each portion is leveled by the rule;
• when the material has hardened, the guides are removed, the recesses are filled with mortar.

Materials for the overhaul of the screed:

• thixotropic mixtures, incl. fast hardening;
• repair bulk mixtures;
• non-shrink concrete mixes.

Dusting with toppings during the overhaul of the screed

Depending on the operational loads on the floor, metallized, corundum or quartz hardeners are used. The first option is the leader in terms of strength and is effectively used on industrial floors. For higher and medium loads, it is advisable to use corundum mixtures. They reinforce the surface of the screed up to two times.

This solution is considered optimal for floors subjected to abrasive loads (warehouses, gas stations, places with high foot traffic, etc.). Quartz hardeners work under conditions of small and medium loads. They are more affordable and are characterized by high decorative possibilities due to staining with colored pigments.

How to dust concrete screed

Technology requires an exceptionally professional approach. Any errors will cause marriage and peeling of the hardener. The screed must be reinforced, with a concrete layer thickness of 7 cm or more. Toppings work on concrete M300 and above.

The readiness of the coating for hardening is determined visually - there should be a slight mark from the shoes on the surface (4-5 mm)

The freshly poured structure is well compacted by vibrators. After pouring, wait about 7 days.

• the composition is distributed on the basis of dosing carts for 2/3 of the total consumption. Sprinkling starts from the junctions, since it is there that the concrete sets the fastest;
• after soaking the topping with moisture, which can be seen from its darkening, grouting is carried out with concrete finishing machines. The mixture must penetrate into the concrete structure;
• after the first grout, the rest of the hardener is immediately added. After it has been impregnated with concrete moisture, grouting is carried out;
• finishing processing is carried out after a deep setting of the screed, when the footprint from the shoe does not fall more than 1 mm deep. In practice, 2 hours is enough for this. To do this, blades are installed on the grinder with a gradual change in the angle of inclination. The finished surface has a characteristic matt sheen.

When all work is completed, you can treat the screed with a special moisture-retaining compound. The floor needs care - for this it is covered with a p / e film. After 24-48 hours, expansion joints are arranged, acting as a seam cutter. After the screed has fully matured, the seams are sealed with polyurethane sealants.

Repair of concrete floor screeds with topping

Restoration of concrete topping screeds can be carried out using two technologies. According to the first method, the structure is repaired and prepared for the application of polymer coatings. Despite the obvious advantages, the technique also has a number of disadvantages. For example, there are high requirements for the quality of concrete preparation, which threatens with high labor intensity and high costs for polymeric materials.

In the second case, polished concrete technologies are used.. A weak surface layer is removed from the screed, dirt is removed. The floor is treated with lithium impregnations of deep penetration. Further, multi-stage polishing is implemented, which strengthens and increases the smoothness of the structure. This is a more economical option. But, in rooms with high chemical loads, polymers (the first method) should be preferred, as they benefit in terms of chemical resistance.

Polished concrete screed is obtained in the following way:

• the surface is polished by planetary type grinders. The working body is a diamond tool;
• defects are eliminated with high-strength repair compounds;
• the surface is polished with discs of different grain sizes;
• processing with lithium hardeners;
• re-polishing with planetary grinders;
• re-treatment with lithium hardeners;
• final polishing.

Dry screed repair

As a rule, in systems of this type, two-layer gypsum fiber boards are used - this material does not like high mechanical loads. If the sheet is damaged, there is only one thing left: to open the finish coating and replace the element with a new one..

The main problem with dry screeds is damage. panel elements gender

A more serious nuisance is the wetting of expanded clay bedding and GVL sheets. In this case, a major overhaul of the structure will be required. Drying the screed to the end and without consequences is unlikely to succeed, without replacement, mold will form in the lower layers, which will eventually move to the walls.

The work is carried out as follows:

• dismantling of the old screed. It is necessary to obtain a solid and stable foundation;
• the surface is carefully inspected for defects. If there are delaminations, weak areas on the plate, they are removed with metal brushes or in any convenient way;
• industrial vacuum cleaner remove debris and dust;
• possible recesses and potholes are repaired with cement-sand mortars. Cracks are cut to a thickness of 50 mm, filled with mortar or silicone sealant. More defects, it makes sense to fill with mounting foam;
• the base is once again dedusted;
• the surface is primed. It is optimal to use compositions with an antiseptic effect. This will not only further strengthen the layer, but also give it hydrophobic characteristics. The soil must dry completely.

Laying damper tape, steam, waterproofing

If the dimensions of the room allow, a polyethylene film is laid on the surface in a single sheet. If not, the material is overlapped, at least 150 mm. The seams are closed with waterproof construction tape. The allowance for the walls is observed, exceeding the height of the new screed.

A compensation tape is launched around the perimeter. Modern damper materials are laid on a self-adhesive base. The material is glued to the bottom of the wall in such a way as to cover the height of the structure.

backfill

As a rule, backfilling of expanded clay is always associated with installation. sheet materials. When installing a dry screed, they work by the zonal method, when both operations are carried out together. After the first, they begin to fill in the next section.

Arrangement of lighthouses, installation of GVL plates:

• when installing a dry screed, temporary beacons are installed. They are removed after leveling the backfill before laying the rigid panels. So the sheets can lie tightly on the expanded clay;
• expanded clay is placed on the base with a layer of 80 mm;
• the profile is recessed into the thickness of the bulk material, stacked with vertical shelves to the bottom. The top shelf is aligned horizontally. The backfill level is derived from them, after which they are carefully removed and placed on the next section;
• after leveling, GVL sheets are immediately laid. Installation is carried out from the wall, after trimming the folded part of the sheet. The smooth edge is pressed tightly against the damper;
• docking is carried out along the seam ledges treated with special glue;
• rows line up with an offset of 250-300 mm;
• after landing on the glue, the panels are fixed with self-tapping screws in increments of 100-150 mm, indented from the edge of the panel by 25-30 mm.

For lighthouses, it is permissible to use special sets of guides for dry screeds or a galvanized profile 27 * 60 mm

The overhaul of the dry screed is ready, it remains only to cut off the protruding edges of the compensation tape and waterproofing, lay the finish coat.

Tools, equipment and accessories

All equipment must be in good working order, preventive inspection and compliance with safety standards are required during work.

To repair a concrete floor screed, you will need:

• pumping stations, compressors, high-pressure apparatuses;
• perforators, jackhammers;
• shot-, sandblasting installations;
• industrial vacuum cleaners;
• trowels, metal brushes, spatulas, shovels, chisels;
• grinders, grinders;
• clean container;
• construction mixer.

findings

Repair of a concrete floor screed should be aimed not only at restoring, but also protecting. When choosing the compositions and technology of work, they are based on the type of structure, the features of its operation. Modern dry repair mixes are considered to be a universal material - they are affordable and have shown high efficiency in practice.

All the nuances of repairing a concrete floor screed are shown in the video:

When repairing a room, quite often you have to deal with the fact that under the old floor covering there is a screed, on which various kinds of defects have appeared in the form of cracks, potholes or swelling. Many masters believe that in this case it is necessary to completely remove the old material and re-align.

However, if the total area of ​​damage does not exceed 30%, then it is possible to repair the floor screed, which will help save a lot of money and time.

Types of damage and their elimination

First of all, it should be noted that each individual defect requires special attention and implies its own unique way elimination. In this case, completely different materials and installation technologies can be used.

Cracks and potholes

• The main problem with old cement floors, a manual on how to repair a floor screed, considers the presence of small cracks or small chips. Such damage often occurs during prolonged use, and indicates the use of poor-quality mortar, in which there is too much sand or water.
• To work, it is first recommended to find all the problem areas and outline them with chalk.
• Then, using a chisel and a hammer, expand the crack or pothole by at least 1 cm on all sides. Also, this area needs to be deepened a little.
• At the next stage, using a vacuum cleaner, remove all debris from the surface.

• Next, it is necessary to treat the cleaned area with a deep-penetrating primer in several layers with an application interval of 4 hours. This will significantly increase the adhesion of the material and give it strength.
• After that you need to prepare cement mortar with proportions of 1 to 3. In this case, it is desirable to add a plasticizer to the composition. Many craftsmen, when repairing floor screeds with small potholes or small cracks, prefer to use glue-cement or quick-hardening leveling mixtures, which are diluted to a mushy state.
• The finished composition is filled with a cut place, leveling with the surface.
• After the solution has hardened, the place of work is polished.

Advice!
If the old screed is shallow, then embroider damaged places and cracks are better for all its depth.
This will prevent further breakage and ensure good adhesion to the surface.

deep cracks

• This type of defect appears as a result of installation errors associated with the preparatory work and the quality of the solution.
• To eliminate such damage, you first need to embroider them to the full depth.. In this case, the repair manual recommends using a puncher and circular saw on concrete. The fact is that with an ordinary chisel and a hammer you cannot go deep into long distance without expanding the area of ​​​​the place of work.
• After cutting the crack, a strobe is made perpendicular to it with a depth of several centimeters so that it crosses the recess, going beyond it by 5-6 cm. Further, recesses of 2-3 cm are drilled at the ends of the strobe.

• The next step is to remove the debris with a vacuum cleaner..
• Then the primer is poured into the resulting recesses and left to dry completely..
• To produce quality repair cracks in the floor screed, you need to prepare a cement mortar in a ratio of 1 to 3. In this case, the filling will be carried out in several stages, the first of which involves the use of a liquid mixture.
• First, pour a small amount of liquid solution into the place where the crack was.. Its consistency should resemble sour cream, and it will allow the material to leak even into the most inaccessible and inconspicuous places.

• At the next stage, we prepare a normal cement mortar and pour it into the crack to the level of the passage of a perpendicular strobe. After that, it is necessary to withstand the time until the mixture solidifies completely.
• Then it is necessary to make a bracket from a piece of reinforcement or thick wire, which is installed in the strobe so that its pins fit into the drilled grooves.
• After that, everyone is covered with a solution, in which a little plasticizer can be added and leveled with the surface.
• At the final stage, the repair of the old floor screed involves. It is done in order to remove the excess solution and disorder the place of work.

Advice!
To facilitate installation, it is best to first make a bracket, and only then prepare a seat for it.

Bloating

• Defects of this kind occur in cases where, before installing the screed, debris was not removed from the surface. You can find swelling with a hammer or a metal rod. They tap the surface, and where the sound is deaf, there will be a peeling of the coating from the surface.
• Some masters believe that such damage must be opened and done, or at home again. However, if this defect does not affect the evenness of the surface, and at the same time there are no cracks and chips on it, then a cheaper method can be used, which will save a lot of time.

• First you need to determine the area of ​​\u200b\u200bdamage with a hammer. After that, it is outlined with chalk or a marker.
• Then you need to take a drill, on which a drill bit for concrete with a diameter of 16 mm is installed. With its help, holes must be made in the surface of the swelling area to the entire depth of the screed. In this case, the distance between them should be about 240 cm.
• Further do-it-yourself repair of a floor screed, which has damage in the form of swelling, involves a primer. In this case, the material must be poured into the holes made so that it flows throughout the cavity. You can use a hair dryer to speed up drying.
• The next step is to decide on the fill material. The fact is that the installation method involves the use of a construction syringe or a plunger pump. So ready mix should be plastic, have good fluidity and not contain lumps.
• Glue-cement or a special mixture for leveling ceilings with large differences is best suited for these purposes. These materials have almost the same qualities and can be used in this type of repair. However, it is worth noting that the price of adhesive cement is much lower, which gives it an additional advantage.

• It is necessary to fill the cavity gradually so that the material inside can flow and fill the entire space. In this case, this process must be carried out until the solution completely fills the holes.
• Drying of the filler takes from 12 to 24 hours. During this time, you can put a load on the surface.
• After the allotted time has passed, the injection sites of the solution are polished.

Advice!
It should be noted that after any repair, the screed over the entire plane must be cleaned of debris and treated with a primer.
It will bind upper layer and protect it from crumbling.

Conclusion

In the presented video in this article you will find additional information on this topic. Also, based on the text presented above, we can conclude that when repairing the screed, it is necessary to detect and eliminate all small damages on its surface. Moreover, each individual defect requires its own method of restoration.

The strength and reliability of a concrete screed has its limits, and whether we like it or not, but over time it may be necessary to repair or completely replace the screed. Mechanical loads and time do their job, cracks, potholes and delaminations appear in the concrete screed, and dust appears on the surface. Of course, it is possible to carry out a complete replacement of the concrete screed, but this is justified in the case when more than 35 - 40% of the total volume of the screed is damaged. The simplest solution would be to repair the floor screed. In addition, you can repair the screed yourself, the main thing is to know what and how to do.

It makes sense to repair a concrete floor screed only if no more than 30% is damaged.

Most often, damage to the screed can be detected when repairing or replacing the flooring. Only after completely tearing off the old coating, such damages as delaminations and cracks in the screed, potholes, and an abundance of dust on the surface become apparent. If the screed is made in the basement, garage or other utility room and is a topcoat, the above damage can be detected visually and the necessary measures to eliminate them can be taken. Finding the damaged area in time and repairing it, you can save not only strength, but also money, avoiding a complete replacement of the screed.

Repair of cracks in the screed

One of the most common screed damage is cracks. They most often appear in places of greatest tension of the screed. Even in a recently poured screed, cracks may appear, which indicates a violation of the screed drying technology and non-compliance with the requirements for concrete mortar.

If this damage is detected in a timely manner and appropriate measures are taken, it is possible to avoid the expansion and deepening of the crack, moisture ingress and prevent the slow but sure destruction of the entire concrete screed. If this damage was found during the replacement or laying of the finish coating, then it will first have to be eliminated and only after that proceed with further work. Otherwise, it will lead to the destruction or deformation of the floor covering.

Cracks in the concrete screed can be filled with a special repair compound

Repair of a concrete screed with cracks is carried out as follows:

• First of all, it is necessary to expand and deepen the crack a little. This can be done with a grinder with a diamond disc. For small cracks, the recess is made up to 20 mm, if the crack is large, then the depth increases slightly.
• As the crack expands, its edges may crumble a little. Therefore, it is necessary to clean such areas and ensure that all edges are strong.

Important! During the expansion of cracks in the concrete screed, the grinder will have quite a lot of dust. Therefore, it is necessary to ensure good ventilation of the room in advance and acquire protective equipment. respiratory tract and eye.

• Along the entire length of the crack, we make cuts perpendicular to the crack with a length of 150 mm and a depth of 20 mm. All cuts are made in increments of 200 - 250 mm.
• Now that the main preparatory work completed, it is necessary to remove all dust and debris from the crack. For these purposes, an industrial vacuum cleaner is perfect.
• After cleaning, apply a deep penetration primer or a primer for mineral compositions.
• We fill the transverse cuts with a special repair compound for the screed and put metal staples inside.
• After the repair composition has hardened in cross sections, we fill the crack and the cuts to the floor level with freshly prepared repair composition, compare it with the floor level and let it dry completely.
• At the end, we grind the screed.

Potholes in the concrete screed can also be filled with a repair compound.

Repair of a concrete screed with potholes is carried out as follows:

• We take a grinder with a diamond disc and cut a pothole along a rectangular perimeter to the entire depth of the screed.
• With the help of a chisel and a hammer, and for large volumes of work, with the help of a perforator, we remove the remains of concrete from the pothole.

Removing dust with a vacuum cleaner

• We remove the remains of the screed and vacuum the resulting hole.
• Apply a deep penetration primer and let it dry.
• We knead the repair composition and fill the pothole with a spatula.
• Without waiting for the complete hardening of the repair composition, with a rail or a wide spatula, we smooth the solution flush with the floor. And let it dry completely.

We grind the screed so that the pothole filled with repair composition does not stand out against the general background

• After complete drying, we grind the surface of the patch until it is completely aligned with the floor.

Repair of delaminations in the screed

Another common damage is the detachment of part of the screed. In such places, the concrete begins to "bubble", and this is quite easy to identify. You just need to take a hammer and lightly tap on the entire surface of the screed. In those places where the concrete has peeled off, the sound from the impact will be dull, and where everything is in order, a sonorous impact will be heard. When the concrete is peeled off, “burrs” and cracks may appear, through which a cloud of dust will fly out when tapped.

Repair of a peeled screed can be carried out in two ways. The first is to cut out the entire damaged area and replace it completely. This method of repair according to the technology of carrying out is similar to the repair of potholes. The second is the injection of a screed and is performed as follows:

Repair of delaminations in concrete screed can be done with epoxy injection

• First of all, we tap the screed in places of delamination in order to reveal the entire area of ​​the damaged area.
• With a marker, we apply an approximate contour of the delamination.
• We take a drill or a puncher and drill holes with a diameter of 6–10 mm over the entire area of ​​the peeling and with a step of 25 mm.
• Using a construction syringe, we pump the repair composition into the holes. We use as a repair epoxy resin with reduced viscosity. We carry out all work in several passes, evenly filling each hole. This will make it possible to partially soak the repair compound into the concrete and then completely fill the place of delamination.
• We stop the injection after the level of the repair staff in the holes stops decreasing.
• We let the screed dry for a day and after that we begin to carry out further work.

Important! If the delamination area is more than 30% of the total area, it makes sense to completely remove the old screed and make a new one.

Dust screed repair

Over time, dust begins to appear on the surface of the screed. This is especially noticeable in rooms where screed is used as a finishing coat, such as in a garage, basement or any other utility room. Over time, the dust becomes more and more, and it is no longer possible to simply sweep it away. The appearance of dust is a consequence of high mechanical loads on the surface of the screed and its "old age". Sometimes dust begins to appear just a few weeks after the start of floor operation, this indicates non-compliance with pouring technology and low quality cement. If it is not possible to dismantle the screed and make a new one, you can repair the cement screed as follows:

• Vacuum the entire surface thoroughly.
• If cracks or potholes are found in the screed, they must be repaired using the technology described above.
• Sand the surface.
• Vacuum again.
• Apply a deep penetration primer and allow to dry.
• Cover the entire area of ​​the screed with a special polymeric dedusting compound. The composition is applied in two layers.

Important! In the event that indoors high humidity, it is necessary to use a special water-emulsifying composition. Another option for dedusting the screed is to paint it. The main thing here is to choose a special paint.

Sometimes a method of reinforcing with fiberglass is used, followed by pouring with a self-leveling mixture. All work is carried out as follows:

• Vacuum the surface.
• Apply a deep penetration primer and let it dry.

Lay fiberglass on a dusty concrete screed

• We apply a layer of glue and, without letting it dry, roll out the fiberglass on top with an overlap between the canvases.
• After the first layer of glue has completely dried, apply the final layer of glue and let it dry.

You can get rid of the "dustiness" of the concrete screed by filling it with a self-leveling mixture.

• You can sand the surface, or you can simply pour a layer of self-levelling compound on top and let it dry completely.

All work on the repair of concrete screed is quite simple and does not require special knowledge. All repair tools can be rented or purchased for personal use for the future. It may take only a few days to complete, while a complete screed replacement can take up to a month.