Most often, screed defects appear due to various violations: in the recipe for preparing the mixture, in the pouring process. A greater number of emerging shortcomings are easily amenable to elimination in a short time. It is only necessary to clearly master the technology, to know the various causes of the formation of a particular defect.

The main types of screed defects

Vulnerabilities of the screed are both very minor and quite serious. The main problem most often encountered is cracks. They have a very different appearance - from small and barely noticeable, to incredibly rough and deep. The following widespread shortcomings are insufficient strength or evenness of the surface, poorly mixed material, slight bonding to the floor, high humidity.

The first thing you need to know is that floor screed is a specific layer of material designed to perfectly level the base. On the surface of the screed, the presence of defects is unacceptable, it should be as even as possible. Only such a surface is suitable for subsequent laying of the material.

Cracks as one of the factors of defect formation

Such well-known screed flaws as cracks often form where high stress is concentrated.

• The appearance of cracks is due to the following reasons:
• Violations of the technology for the manufacture of mortar for screed;
• During the laying of the screed, the features of the room were not taken into account;
• Inaccuracies in the process of calculating the amount of ingredients for the mixture;
• Deviations from the norm of indicators of humidity and temperature in the room;
• Use of low-quality equipment in work.

Incorrect filling preparation technology

The most common today is the "strip" fill. With this technology, it is impossible to obtain a continuous layer of screed, because it looks like strips that are not interconnected in any way.

The most important step is the competent connection of the strips by proper installation. An important nuance is the subsequent alignment procedure. If major violations are made in the technology, rather large cracks will appear on the seams of the strips.

Extra space - what is it for

During the manufacture of the screed, special attention should be paid to the so-called expansion gaps. Often they are formed near the walls, in a circle of columns. In the case when this type of gap is not made, you can encounter a lot of adverse consequences: the appearance of voids, cracks of great depth in the screed.

Adhere to one simple rule: gaps of 10 millimeters or more are required near walls or columns. If everything is done correctly, screed defects will be minimized.

Common mixing mistakes

The rapid appearance of cracks cannot be avoided if gross errors are made during the preparation of the composition. It must contain all the necessary components in the correct amount. It is recommended to knead them very carefully until the mixture reaches the desired consistency.

Remember that due to air ingress, the surface of the screed dries relatively quickly, and then shrinks faster, unlike the lower layers. This explains the crystallization of cement, which causes multiple microscopic cracks. To avoid such a shortcoming, do not forget - the surface of the screed needs constant moisture while the solidification process is in progress.

The appearance of screed defects is also highly likely in the case when water occupies a large part among the components of the mixture. Drying, large gaps will begin to appear on the screed. If there is a lack of liquid, the screed will be divided into layers. It must have the perfect consistency. Small lumps or foreign inclusions are not allowed.

When performing major repairs in a room for any purpose, special attention is required to the technical condition of the floors. After long-term operation, the coating may have a number of defects, which can only be corrected by a major overhaul of the floor screed.

After a long use of the concrete floor, it can receive both minor damage and become covered with large cracks, which can be fixed only by a complete replacement of the screed.

Defect classification

The easiest way is to completely dismantle the existing coating to the very base and arrange a new screed. Such actions justify themselves if there are no more ways to restore the old screed. Under normal circumstances, this is unacceptable for a number of reasons:

Scheme of dismantling a damaged floor screed.

1. Most often, the old flooring can be repaired and updated without resorting to such drastic methods.
2. Dismantling old screeds in a residential area is a very noisy and extremely polluting event; during the work, cement dust will spread throughout the entire volume of the apartment.
3. It is necessary to dismantle the existing screed to the very foundation, otherwise the procedure loses its meaning. However, it is not known what state the foundation itself is in. The case may end with the repair of load-bearing reinforced concrete structures, which is very expensive. Ideally, applying a scrupulous approach to the issue, it is necessary to do so in order to ensure the safe and durable operation of the premises. But in the short term, this approach may not be justified.
4. To repair the floor screed by completely replacing it is the most expensive way of all available.

It would be more correct to remove the finished top flooring, clean the surface of the existing screed and visually examine it, determining the number and size of defects. In the process of studying the entire area of ​​the concrete surface, it is recommended to gently tap with a hammer for the presence of hidden voids in the thickness of the screed as a result of delamination. A dull sound will accurately indicate the location of such a defect. After all damages and their number are determined, you can start choosing a way to eliminate them.

There are several types of wear on old concrete floor coverings:

Delaminations occur due to temperature changes and the effect of moisture on concrete.

1. Cracks of various depths and degrees of opening occur over time in the thickness of the coating as a result of loads and temperature effects.
2. Potholes and depressions appear during operation after constant mechanical impacts on the concrete layer. This may be the movement of heavy pieces of furniture or musical instruments (for example, a piano) or vibration load from a washing machine. In industrial premises, the range of loads on floors is very wide.
3. Delamination of concrete in a certain area is formed with the simultaneous effect of moisture and temperature changes.
4. The low strength of the surface layer of the screed is the result of an initially low grade of cement-sand mortar or concrete. On such a surface, dust of cement and sand from the slightest mechanical impact is constantly present.

Elimination of minor damage

Repair of small cracks begins with opening them in width and depth. For this, an angle grinder with a cutting wheel for stone and concrete is used. On both sides of the defect, the screed is cut in a circle to a depth of 5 cm so that after removing pieces of the old mortar, a rectangular groove 2-3 cm wide is obtained. It is cleaned and dust is removed to assess the sufficiency of the cut depth. If it turns out that the crack goes to the very base, then you will have to do the same work as in the case of through wide cracks.

Sequence of screed repair.

The cut groove is sealed after applying a primer to its walls, which will lead to dust removal and hardening of the existing concrete layer. It may be necessary to prime several times, especially when it is noticeable that the surface strongly absorbs the applied composition. To complete the last stage of the repair, you need to prepare a special cement-sand mortar on PVA glue. The recipe is as follows: glue is mixed with water in a ratio of 1:3, after which the mortar itself is mixed on this basis, the ratio of cement and sand is 1:3. Since the amount of work is small, it is best to do the batch in a plastic bucket (possible from under the paint) with an electric drill with a mixing nozzle. If the latter is absent, you can use a piece of wire with a diameter of 6 mm, one end of which is bent up or in the form of a ring, and the other is fixed in the chuck of a power tool.

With the help of a trowel and a rule, the cut crack is filled, and the surface is smoothed, removing the remnants of the solution. Subsequent work can be carried out no earlier than 20 days after the completion of the repair, this applies to all types of work to restore the screed. The same method can be used to repair potholes and other mechanical damage in the surface of a concrete screed.

Deep Crack Filling Technology

The scheme of sealing cracks in a concrete screed.

Through wide cracks are expanded to the very base with a perforator, broken pieces of old mortar and dust are removed. For this purpose, it is best to use compressed air to blow out any excess debris. If a crushed stone pillow is found as a base, it will need to be compacted and filled with liquid cement milk at the cutting site, if possible. In this case, the milk should fall under the cut edges of the screed, after which you need to give time to solidify. The base in the form of a reinforced concrete slab must be primed together with the edges of the resulting groove.

Further repair of the screed consists in filling the groove with a special compound. You can do this work by preparing the same solution as in the previous case, and smoothing it out with a rule. But it should be understood that cracks of this size do not occur in the screed just like that and can reappear, so it is recommended to withstand the technology. In this case, you should not save on self-preparation, it is better to purchase a ready-made thixotropic mixture for repairing the floor in the distribution network, at the same time buy a special damper cord-seal, this is used for the construction of expansion joints.

After stirring, the entire cut-out niche is filled with the mixture, while vertical markers made of thin steel wire are installed along the entire crack. When the thixotropic mixture sets, the markers can be pulled out so that they come out more easily, they should first be lubricated with grease.

The next stage is the laying of a damper cord, under which a narrow groove 5 cm deep is cut. After this operation, the groove is sealed with a plastic sealant based on silicone or polyurethane. As can be understood from the technology, the result of such a repair is the construction of an expansion joint at the site of a large floor crack. Whatever the reasons for its occurrence, new defects will not appear in this place.

Layering of concrete in the thickness of the screed can be eliminated by injection. As soon as all places with this defect are found, it is necessary to drill holes in the screed within these areas using a perforator and a drill with a diameter of 12 to 20 mm, the distance between the holes is 250 mm. Next, a special composition based on epoxy resins should be carefully poured into them. If possible, it is better to use a syringe. Pouring should be carried out until all voids and pores are filled, the process should be done intermittently, allowing the composition to soak into the concrete. Repairing a floor screed with this method is not difficult work, but it requires attention and patience. After the epoxy glue hardens, which will occur within a day, you can proceed to further work.

The weakened surface layer of the screed can be made stronger with modern building deep-penetrating compositions based on polyurethane. Such impregnations allow you to raise the grade of the screed solution from M50 to M300 to the required depth. After the floor is treated with polyurethane compounds, the formation of cement dust will stop, and a protective film up to 200 microns thick will appear on the concrete surface.

By performing restoration work on concrete flooring, you can significantly save money, which will inevitably be spent during the dismantling and installation of a new screed.

When performing major repairs in a room for any purpose, special attention is required to the technical condition of the floors. After long-term operation, the coating may have a number of defects, which can only be corrected by a major overhaul of the floor screed.

After a long use of the concrete floor, it can receive both minor damage and become covered with large cracks, which can be fixed only by a complete replacement of the screed.

Defect classification

The easiest way is to completely dismantle the existing coating to the very base and arrange a new screed. Such actions justify themselves if there are no more ways to restore the old screed. Under normal circumstances, this is unacceptable for a number of reasons:

1. Most often, the old flooring can be repaired and updated without resorting to such drastic methods.
2. Dismantling of old screeds in a residential area is a very noisy and extremely polluting event; during the work, cement dust will spread throughout the entire volume of the apartment.
3. It is necessary to dismantle the existing screed to the very foundation, otherwise the procedure loses its meaning. However, it is not known what state the foundation itself is in. The case may end with the repair of load-bearing reinforced concrete structures, which is very expensive. Ideally, applying a scrupulous approach to the issue, it is necessary to do so in order to ensure the safe and durable operation of the premises. But in the short term, this approach may not be justified.
4. Repairing the floor screed by completely replacing it is the most expensive way of all available.

It would be more correct to remove the finished top flooring, clean the surface of the existing screed and visually examine it, determining the number and size of defects. In the process of studying the entire area of ​​the concrete surface, it is recommended to gently tap with a hammer for the presence of hidden voids in the thickness of the screed as a result of delamination. A dull sound will accurately indicate the location of such a defect. After all damages and their number are determined, you can start choosing a way to eliminate them.

There are several types of wear on old concrete floor coverings:

Delaminations occur due to temperature changes and the effect of moisture on concrete.

1. Cracks of various depths and degrees of opening occur over time in the thickness of the coating as a result of loads and temperature effects.
2. Potholes and depressions appear during operation after constant mechanical impacts on the concrete layer. This may be the movement of heavy pieces of furniture or musical instruments (for example, a piano) or vibration load from a washing machine. In industrial premises, the range of loads on floors is very wide.
3. Delamination of concrete in a certain area is formed with the simultaneous effect of moisture and temperature changes.
4. The low strength of the surface layer of the screed is the result of an initially low grade of cement-sand mortar or concrete. On such a surface, dust of cement and sand from the slightest mechanical impact is constantly present.

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Elimination of minor damage

Repair of small cracks begins with opening them in width and depth. For this, an angle grinder with a cutting wheel for stone and concrete is used. On both sides of the defect, the screed is cut in a circle to a depth of 5 cm so that after removing pieces of the old mortar, a rectangular groove 2-3 cm wide is obtained. It is cleaned and dust is removed to assess the sufficiency of the cut depth. If it turns out that the crack goes to the very base, then you will have to do the same work as in the case of through wide cracks.

The cut groove is sealed after applying a primer to its walls, which will lead to dust removal and hardening of the existing concrete layer. It may be necessary to primer several times, especially when it is noticeable that the surface strongly absorbs the applied composition. To complete the last stage of the repair, you need to prepare a special cement-sand mortar on PVA glue. The recipe is as follows: the glue is mixed with water in a ratio of 1:3, after which the mortar itself is mixed on this basis, the ratio of cement and sand is 1:3. Since the amount of work is small, it is best to do the batch in a plastic bucket (possible from under the paint) with an electric drill with a mixing nozzle. If the latter is absent, you can use a piece of wire with a diameter of 6 mm, one end of which is bent up or in the form of a ring, and the other is fixed in the chuck of a power tool.

With the help of a trowel and a rule, the cut crack is filled, and the surface is smoothed, removing the remnants of the solution. Subsequent work can be carried out no earlier than 20 days after the completion of the repair, this applies to all types of work to restore the screed. The same method can be used to repair potholes and other mechanical damage in the surface of a concrete screed.

Back to index

Deep Crack Filling Technology

Through wide cracks are expanded to the very base with a perforator, broken pieces of old mortar and dust are removed. For this purpose, it is best to use compressed air to blow out any excess debris. If a crushed stone pillow is found as a base, it will need to be compacted and filled with liquid cement milk at the cutting site, if possible. In this case, the milk should fall under the cut edges of the screed, after which you need to give time to solidify. The base in the form of a reinforced concrete slab must be primed together with the edges of the resulting groove.

Further repair of the screed consists in filling the groove with a special compound. You can do this work by preparing the same solution as in the previous case, and smoothing it out with a rule. But it should be understood that cracks of this size do not occur in the screed just like that and can reappear, so it is recommended to withstand the technology. In this case, you should not save on self-preparation, it is better to purchase a ready-made thixotropic mixture for repairing the floor in the distribution network, at the same time buy a special damper cord-seal, this is used for the construction of expansion joints.

After stirring, the entire cut-out niche is filled with the mixture, while vertical markers made of thin steel wire are installed along the entire crack. When the thixotropic mixture sets, the markers can be pulled out so that they come out more easily, they should first be lubricated with grease.

The next stage is the laying of a damper cord, under which a narrow groove 5 cm deep is cut. After this operation, the groove is sealed with a plastic sealant based on silicone or polyurethane. As can be understood from the technology, the result of such a repair is the construction of an expansion joint at the site of a large floor crack. Whatever the reasons for its occurrence, new defects will not appear in this place.

Layering of concrete in the thickness of the screed can be eliminated by injection. As soon as all places with this defect are found, it is necessary to drill holes in the screed within these areas using a perforator and a drill with a diameter of 12 to 20 mm, the distance between the holes is 250 mm. Next, a special composition based on epoxy resins should be carefully poured into them. If possible, it is better to use a syringe. Pouring should be carried out until all voids and pores are filled, the process should be done intermittently, allowing the composition to soak into the concrete. Repairing a floor screed with this method is not difficult work, but it requires attention and patience. After the epoxy glue hardens, which will occur within a day, you can proceed to further work.

The weakened surface layer of the screed can be made stronger with modern building deep-penetrating compositions based on polyurethane. Such impregnations allow you to raise the grade of the screed solution from M50 to M300 to the required depth. After the floor is treated with polyurethane compounds, the formation of cement dust will stop, and a protective film up to 200 microns thick will appear on the concrete surface.

By performing restoration work on concrete flooring, you can significantly save money, which will inevitably be spent during the dismantling and installation of a new screed.

Why is it important to have a level subfloor? The fact is that not only the quality of laying the decorative flooring, but also its service life depends on the quality of the preparation of the base. In this connection, before starting work, it is necessary to study the condition of the subfloor. It would be more correct to say what defects the floor has. And then, depending on the selected flooring, take measures to eliminate or not eliminate the identified defects.

Depending on the material and construction of the floor, there may be various defects that require attention. Conventionally, they can be divided: defects in the screed, defects in the wooden floor. Next, we will consider in detail possible floor defects, ways to eliminate them, and analyze what effect this or that defect has on such floor coverings as ceramic tiles, linoleum and laminate.

Screed defects

The most common defects in the screed are potholes, bumps, cracks, dust and unevenness (height difference, waves), rarely broken off parts.

Elimination of potholes and pits

Potholes and pits are among the most innocuous defects and the most easily fixed. If potholes or pits of a small size are not more than 5 mm, then you can ignore them. If they are larger (up to 5 cm "approximately"), then they will not be able to have a big impact on the laying and operation of tiles or laminate. But on the linoleum, they will definitely appear their mark, which in turn will spoil the entire interior. In other words, potholes will appear on it. If the size of the potholes is larger, then they should be eliminated, regardless of the type of future flooring.

The holes need to be patched. For these purposes, any mixture based on cement is suitable. It is most convenient to buy a specialized mixture than to make the solution yourself. Why? The fact is that ready-made mixtures, as a rule, contain additives that give the solution such important properties for these works as plasticity, adhesion to the base, and drying speed.

To eliminate such floor defects as potholes, you should use a solution made on the basis of the same component as the screed, i.e. mostly cement. Otherwise, the putty will soon move away from the base. It does not hurt to pre-treat the surface with a primer, this will improve adhesion and improve the quality of puttying.

Pits and potholes of small size will not affect the laying of tiles or laminate. However, any screed defects will appear on linoleum. Pits and potholes are eliminated by puttying with a cement-sand mortar in a cement:sand ratio of 1:3, or using a specialized mixture.

Elimination of bumps

This floor defect is bad for any topcoat, and must be eliminated without fail. An exception can only be when laying tiles, and then only if the bumps are smaller in height than the layer of tile adhesive.

In fact, in this case, bumps can be eliminated by raising the level of the floor, i.e. make a new layer on top of the existing screed, this is a universal way to solve problems with all floor defects. Another way is to cut the bumps. However, this method is not always possible to implement.

How to cut the bumps on the screed? You can go two ways. First, pre-cut them with a chisel or puncher, and then grind them with a grinder. Or use only the grinder. The choice in favor of one or another method is determined mainly by the size of the roughness and the presence of a tool. It should be noted that in order to eliminate this floor defect by grinding, it is necessary to purchase a special wheel for cutting and grinding stone, the so-called diamond wheel. It will be very problematic to do this work with ordinary circles.

The bumps on the screeds can be cut or sanded. The bumps are cut down with a chisel or perforator. However, the surface after such treatment remains uneven. You can grind the bumps with a special diamond wheel and a grinder.

Crack repair

Such a defect as cracks, if we are not talking about a split and swinging screed, do not have a big impact on the laying and operation of the floor covering. Except if the crack is the size of a "ditch". Most likely she will perform on linoleum. Then it needs to be removed. To do this, it needs to be embroidered, i.e. remove all poorly holding pieces and putty by analogy with cavities.

Removing dust from the screed

A fairly harmless floor defect, which is often forgotten. But at the end of the repair, especially after laying the laminate, they wonder why the floors are always dusty. And the fact is that the screed is dusty. It is imperative to get rid of this defect, and before laying the coating, it is not difficult to do so.

The best moment is when all the rough finishing is done and you can start finishing. You need to start by removing the maximum amount of dust mechanically. It is convenient to use a dirt vacuum cleaner for this purpose, i. industrial vacuum cleaner. He will get the job done and not mess up. After that, the floor should be treated with a primer.

Irregularity or difference in height of the concrete floor

With regard to this floor defect, it can be said unequivocally that it is the result of a poor-quality screed device. In the vast majority of cases, it can be corrected only by pouring a new layer of screed. The main criterion for assessing unevenness can be the recommendations of laminate manufacturers. This height difference should not exceed about 2 mm per 1 m.

What is fraught with this defect of the floor for floor coverings?

Linoleum. All irregularities linoleum will easily go around. As a result, there will be similar drops and drops on the surface of linoleum.

Laminate. If there are differences, the laminate panels will play, and as a result, the strength of the interlock will decrease. Then the process is very simple. The lock diverges and dust and moisture get there when washing the floors, the laminate quickly fails and needs to be replaced.

Ceramic tile. If there are significant surface differences, then it is very problematic to perform high-quality tiling. In addition, there will be excess consumption of tile adhesive, which will also increase the cost of work. If the surface is even, then even a novice master can lay the tiles, and the glue consumption will be minimal, as per the instructions.

If irregularities in the form of a height difference or waves are detected on the screed, then the easiest way to eliminate such defects is self-leveling self-leveling floors. A self-leveling mortar is poured onto the surface of the screed, which, under the force of gravity, assumes a strictly horizontal position. With small differences, the solution layer will be small, and the increase in floor level will be insignificant. As a result, after 3-5 days you will have a perfectly flat floor suitable for laying any floor covering.

wood floor defects

The main defects of a wooden floor are creaks, loose boards, gaps between boards, floor play and rotten boards.

Most often, when it comes to defects in a wooden floor, it implies its suitability for laying a particular floor covering. Therefore, we can immediately say that not one of the above defects is unacceptable, and all of them must be eliminated.

In order for the decorative flooring to serve for a long time, it is necessary to ensure that the wooden floor is even and hard. Accordingly, the first step is to remove any rotten parts and replace them with new ones. Next, plywood or chipboard is laid on the floor and rigidly fastened to the floor base. Plywood is more commonly used due to the fact that it is easier to work with.

In this simple way, you can get rid of all the defects of the wooden floor. Despite the fact that this is a fairly simple job, you should pay attention to one feature. If it is supposed to be linoleum as a decorative floor covering, then you should make sure that the edges of the plywood sheets do not protrude relative to each other. The fact is that these edges can appear on the surface of the linoleum.

There is only one method for leveling a wooden floor. Rotten and broken boards are removed. Logs with the help of anchors are firmly fixed to the ceiling. Plywood is laid on the floor in a checkerboard pattern, and pulled together with boards with self-tapping screws in increments of 15-20 mm. To level the wooden floor, plywood 10 mm thick is used; you can increase the strength of the floor by laying plywood in two layers.

We examined all the most common defects in screed and wooden floors, and their impact on the operation of various floor coverings. In order for the floor covering to be easy to install and serve for a long time, most defects must be eliminated. However, minor floor defects generally do not affect installation or the life of the floor covering.

Inspection object: concrete screed

Address of construction expertise: Moscow

The purpose of the construction expertise: to assess the quality of the completed construction and installation work on the installation of the screed for compliance with the requirements of the current regulatory and technical documentation (screed expertise).

Technical means of control used at the facility: DISTO classic/lite laser rangefinder, Canon digital camera, metric tape measure GOST 7502 - 80, Pulsar ultrasonic tester.

When examining and drawing up an expert opinion, regulatory documents were used.

General provisions for determining quality

The technical inspection of the Customer's object was carried out in order to make an examination of the screed. The basis for the technical survey is the Construction Expertise Agreement, which specifies the purpose of the survey and the list of works to be performed. When performing survey work, the obtained data were taken into account, defects were photographed. The results of the survey, which served as the basis for this conclusion, are given as of October 05, 2010.

Diagnostic examination

Inspection of building structures of buildings and structures is carried out, as a rule, in three interconnected stages:

• preparation for the survey;
• preliminary (visual) examination;
• detailed (instrumental) examination.

In accordance with the requirements of SP 13-102-2003 clause 6.1 Preparation for surveys provides for familiarization with the object of the survey, design and executive documentation for the structure and construction of the structure, with documentation for the operation and repairs and reconstruction that took place, with the results of previous surveys.

The expert made an external inspection of the object, with selective fixation on a digital camera, which meets the requirements of SP 13-102-2003, clause 7.2. The basis of the preliminary examination is the inspection of a building or structure and individual structures using measuring instruments and devices (binoculars, cameras, tape measures, calipers , probes, etc.).

Measurement work was carried out in accordance with the requirements of SP 13-102-2003, clause 8.2.1 The purpose of measurement work is to clarify the actual geometric parameters of building structures and their elements, to determine their compliance with the project or deviation from it. Instrumental measurements clarify the spans of structures, their location and pitch in plan, cross-sectional dimensions, height of rooms, marks of characteristic nodes, distances between nodes, etc. Based on the measurement results, plans are drawn up with the actual location of structures, sections of buildings, drawings of working sections of load-bearing structures and junctions of structures and their elements.

Classifier of the main types of defects in construction and building materials industry

• Critical Defect(when performing construction and installation work) - a defect in the presence of which a building, structure, part or structural element is functionally unsuitable, further work under the conditions of strength and stability is unsafe, or may lead to a decrease in these characteristics during operation. A critical defect is subject to unconditional elimination before the start subsequent work or with the suspension of work.
• Major Defect- a defect, in the presence of which the operational characteristics of construction products and their durability are significantly impaired. A significant defect is subject to elimination before its concealment by subsequent works.

In this case, a defect is every single deviation from design decisions or non-compliance with the requirements of the standards.

The expert carried out a diagnostic survey of the object with the determination of the quality of the construction and installation works performed in accordance with the requirements SNiP. The survey was carried out by the method of measuring quality control.

When assessing the quality of the performed construction and installation works on the device, the following was established:

When tapping the concrete screed coating on numerous areas of the floor surface, changes in the nature of the sound were recorded. This fact testifies to a poorly executed base, as a result of which there is no adhesion of the upper floor covering to the base.

Construction expertise comment

According to the Decree of the Government of the Russian Federation N 1025 of August 15, 1997, On the Approval of the Rules for Public Services for the Population in the Russian Federation, “If a law or other regulatory legal act of the Russian Federation adopted in accordance with the law provides for mandatory requirements for the quality of a service (work), the performer is obliged to provide a service (perform work) that meets these requirements.

According to GOST R 52059-2003 Household services. Services for the repair and construction of housing and other buildings. General technical conditions, clause 5.20 “Main work on the repair of basements, cellars, floors of all types, roofs, cladding of external or internal walls with various materials, plastering walls, ceilings, columns, filing ceilings, as well as facing, painting, wallpaper, glass , insulation work must be carried out in accordance with SNiP 3.04.01.

The changes in the nature of the sound detected during the survey when the floor covering is tapped are a violation of the requirements of SNiP 3.04.01-87 “Insulating and finishing coatings”, table 25, according to which “when checking the adhesion of monolithic coatings and coatings made of hard tile materials with underlying floor elements tapping should not be a change in the nature of the sound.

The main requirements for finished floor coverings are given in Table 25:

Table 25

Technical requirements
Deviations of the coating surface from the plane when checking with a two-meter control rail should not exceed, mm, for: earthen, gravel, slag, crushed stone, adobe coatings and pavement coatings - 10 asphalt concrete coatings, on a layer of sand, end, from cast-iron slabs and bricks - 6 cement-concrete, mosaic-concrete, cement-sand, polyvinyl acetate-cement concrete, metal-cement, xylolite coatings and coatings made of acid-resistant and heat-resistant concrete - 4 coatings on a layer of mastics, end, cast iron and steel plates, bricks of all types - 4 coatings from cement-concrete, cement-sand, mosaic-concrete, asphalt-concrete, ceramic, stone, slag-ceramic slabs - 4 polyvinyl acetate, plank, parquet and linoleum coatings, roll coatings based on synthetic fibers, from polyvinyl chloride and superhard fiberboards - 2
Ledges between adjacent products of coatings made of piece materials should not exceed for coatings, mm: from paving stones - 3 brick, end, concrete, asphalt concrete, cast iron and steel slabs - 2 from ceramic, stone, cement-sand, mosaic-concrete, slag-ceramic slabs - 1 plank, parquet, linoleum, polyvinyl chloride and superhard fiberboards, polyvinyl chloride plastic - not allowed
Ledges between coatings and floor edging elements - 2 mm	Measuring, at least nine measurements for every 50-70 m2 of the coating surface or in one room of a smaller area, acceptance certificate
Deviations from the specified coating slope - 0.2% of the corresponding room size, but not more than 50 mm
Deviations in coating thickness - no more than 10% of the design	The same, at least five measurements, acceptance certificate
When checking the adhesion of monolithic coatings and coatings made of rigid tile materials with underlying floor elements by tapping, there should be no change in the nature of the sound	Technical, by tapping the entire floor surface in the center of the squares along a conditional grid with a cell size of at least 50x50 cm, acceptance certificate
Gaps should not exceed, mm: between plank boards - 1 between parquet boards and parquet boards - 0.5 between adjacent plans of piece parquet - 0.3	Measuring, at least five measurements for every 50-70 m2 of the coating surface or in one room of a smaller area, acceptance certificate
Gaps and gaps between skirting boards and floor coverings or walls (partitions), between adjacent edges of linoleum panels, carpets, rolled materials and tiles are not allowed	Visual, the entire surface of the floor and junctions, the act of acceptance
The surface of the coating should not have potholes, cracks, waves, swellings, raised edges. The color of the coating must match the design	The same, the entire surface of the floor, the act of acceptance

When examining the floor, numerous cracks were recorded in the screed with an opening width of up to 2 mm.

Expert commentary

This fact is a violation of the requirements of SNiP 3.04.01-87 "Insulating and finishing coatings", according to which:

Requirements for finished flooring

4.43. The main requirements for finished floor coverings are given in Table 25.

Table 25

Expert opinion

The presence of cracks indicates a loss of strength and integrity of the floor structure.

When checking cracks using an ultrasonic tester, the maximum depth of their occurrence was set to 35 mm.

Expert commentary

The revealed value of the depth of occurrence of cracks indicates the absence of solidity of the floor.

When examining individual exposed sections of the floor screed, the soundproofing layer was filled with expanded clay with a fraction of 15 mm.

Expert commentary

The revealed fineness of loose soundproofing material - 15 mm, is a deviation from the requirements of "SNiP 3.04.01-87 Insulating and finishing coatings, p.4.20", according to which the fineness of loose soundproofing material should not exceed 10 mm.

SNiP 3.04.01-87 Insulating and finishing coatings

4. Installation of floors general requirements for soundproofing

4.18. Loose soundproofing material (sand, coal slag, etc.) must be free of organic impurities. The use of backfills made of dusty materials is prohibited.

4.19. Gaskets must be laid without gluing to floor slabs, and slabs and mats - dry or with gluing on bituminous mastics. Soundproof pads under the logs must be laid throughout the entire length of the log without breaks. Tape gaskets for room-sized prefabricated screeds should be placed in continuous strips along the perimeter of the premises close to walls and partitions, under the joints of adjacent slabs, and also inside the perimeter - parallel to the larger side of the slab.

4.20. When installing sound insulation, the requirements of Table 18 must be observed.

Table 18

Technical requirements	Limit deviations	Control (method, scope, type of registration)
The fineness of bulk soundproofing material - 0.15-10 mm		Measuring, at least three measurements for every 50-70 m2 of backfill, work log
Moisture content of bulk material between the lags	No more than 10%
Width of soundproof pads, mm: under logs 100-120; for prefabricated screeds with the size "per room" along the perimeter - 200-220, inside the perimeter - 100-120		Measuring, at least three measurements for every 50-70 m2 of floor surface, work log
The distance between the axes of the strips of soundproof gaskets inside the perimeter of the prefabricated screeds with the size "per room" - 0.4 m		The same, at least three measurements on each screed slab, work log

The expert measured the propagation velocity of ultrasound in the floor screed structure to determine the average compressive strength, class and brand of concrete.

Measurements were made by ultrasonic tester Pulsar, according to GOST 17624-87 “Concrete. Ultrasonic method for determining strength. The number and location of controlled sections on the structures are established taking into account the requirements of GOST 18105-86 “Concrete. Strength control rules.

According to the measurements performed, calculations of the average strength of concrete were made, the grade and class of concrete compressive strength were determined.

The results are listed in Table No. 1.

Table #1

	Propagation speed ultrasound in areas	The nearest concrete strength class for compression	Strength grade of concrete for compression

According to the results of ultrasonic examination, the strength grade of concrete was M 200.

Construction expertise conclusion

The conclusion of the construction expert on the inspection of the screed

The purpose of the survey: to assess the quality of the completed construction and installation work on the installation of the screed for compliance with the requirements of the current regulatory and technical documentation.

The quality of construction and installation works performed by the Contractor does not meet the requirements of regulatory and technical documents, namely:

The floor covering device was made in violation of the requirements of the current regulatory and technical documents. According to the examination, these violations of regulatory requirements are the result of:

• non-observance of work production technology;
• lack of proper control over the work by the contractor;

As a result of violations of regulatory requirements, this coating cannot provide the design bearing capacity. The fact that part of the floor covering is subject to changes in the nature of the sound when tapped (fixed during the survey) indicates the presence of voids in such areas.

According to the examination, the areas where voids were found are also subject to cracking, which can subsequently lead to the complete destruction of the upper floor covering.

Thus, the audit found that the elimination of the identified violations is not possible without partial dismantling of the upper floor covering in areas with cracks.

To bring the quality of construction and installation works in line with the current regulatory requirements, it is necessary to eliminate the above disadvantages.

To eliminate the shortcomings of the work performed with the screed, we recommend: contact the contracting construction organization with the requirement to bring the quality of the work performed in accordance with current regulatory requirements.