Today there are many ways to perform work related to leveling the subfloor for further installation floor coverings. The most common is floor screed using various cement-based mixtures. This applies to both pouring the rough leveling layer and the finishing screed. All work related to leveling the floor with cement mortars, even if done by hand, must meet certain requirements, many of which are regulated in the relevant regulatory document (SNiP).
Whichever of the mixtures used today is used for the specified purposes, it is advisable to adhere to the existing tolerances. We will discuss further what technologies can be used to produce a durable floor screed that meets the requirements using appropriate video materials, which will make it easier to perceive the information.
Requirements for floor screed
Carrying out work related to the installation of carriers building structures, the importance of meeting their specific requirements should be taken into account. This also applies to floor screeds, both rough and finishing. After all, the durability of the flooring materials, which will be installed later, will depend on their strength. So, before carrying out the work yourself, it makes sense to familiarize yourself with some of the fundamental requirements set out in the latest edition of SNiP, which a high-quality floor base must meet. Which technical specifications are prescribed in SNiP for cement floor screeds, which are important when arranging them with your own hands in residential premises? Here are the main ones:
- minimum thickness;
- bending strength;
- the need for waterproofing;
- minimum layer over pipe communications;
- the need for reinforcement;
- location on the floor map expansion joints.
The minimum layer directly depends on the mixture used. The thickness of the cement-sand composition, according to SNiP, in residential premises should not be less than 30 mm. For ready-made polymer-cement mixtures, especially those with reinforcing fibers included in the composition, smaller deviations are allowed (at least 15 mm). If pipe communications are located under the screed, the minimum layer is 40 mm, regardless of the characteristics of the solution used.
The strength of the coating is difficult to determine without special technical means. Whether or not the basis meets these requirements, which are prescribed in SNiP, can only be determined indirectly. To be sure of the strength of the manufactured surface, you must observe the proportions and quality of the components used to prepare working mixtures and follow the technological sequence when constructing both the rough and the finishing base.
A waterproofing barrier is needed in those cases, and this is indicated in SNiP, when there is a threat of waterlogging of the screed due to various reasons, as well as when pouring liquid mixtures, in order to ensure proper hydration of the cement included in the mixture. This is necessary for high-quality crystallization of the binder during its maturation, on which the final strength of the structure directly depends.
A screed made using any technology is reinforced if its thickness exceeds 50 mm. This standard is prescribed in SNiP for rooms with a small and medium load on the floor surface, that is, residential. Reinforcement provides the base of the floor with additional strength and protects it from cracking. Indoor screeds less than 50 mm can be reinforced under certain operating conditions (temperature changes above a heated floor system, for example). Rough cement bases do not need reinforcement, since the main load falls on the overlying finishing layer.
A technological map of the floor, taking into account all the parameters of the screed, is developed when filling large areas. The map is a technological guide, a kind of project, which indicates the sequence of work, the characteristics of the materials used, the location of expansion joints and the distances between them, and other technical information.
When creating a floor map, engineers coordinate all the nuances so that the resulting surface meets the requirements specified in SNiP for the structure in accordance with the expected loads and operational features. When arranging rough and finishing subfloors on Not large areas, in developing technological maps There is no particular need, since the work is not voluminous and does not last long.
When pouring a cement screed with their own hands, home craftsmen rarely pay attention to the requirements set out in SNiP. It is more important for them to know the rules for preparing the solution, the technological sequence of work, and the availability of visual information, which can be gleaned from videos of the corresponding content. Especially when we're talking about on the production of a finishing base from ready-made mixtures, it is assumed that manufacturers must ensure that their product complies with the requirements of SNiP and other regulatory documents. To correctly lay the screed, including the rough screed, with your own hands, all you have to do is carefully read the manufacturer’s instructions and do the work in accordance with the recommendations.
Basic technologies for screeding with various mixtures
Among the technologies that are used today for arranging subfloors for various functional purposes inside residential premises, the main ones are the following:
- classical concrete pouring and its varieties;
- semi-dry screed using German technology;
- production of surfaces for laying floor coverings using ready-made packaged mixtures;
- final leveling with self-leveling mortars.
Each of these technologies has its own priority area of application. When it is better to use what when constructing a floor base with your own hands, we will consider further.
Concrete base and its varieties
Previously, there was no alternative to concrete, so screeds were made only from this material. Nowadays, concrete is used less and less for finishing screeds inside living spaces. However, due to its low cost, concrete remains indispensable for rough pouring, when it is often necessary to form thick leveling layers. Moreover, to form the rough base, a depleted solution with a low content of binder components is used.
Concrete floor screed, the manufacturing technology of which is ideally suited for a rough foundation, has recently begun to be constructed from modified materials, where instead of heavy and cold crushed stone, lightweight fillers with thermal insulation properties are used. The most used of them are expanded clay concrete and polystyrene concrete. The first is used only to form a rough layer, since expanded clay granules are large in size, which makes it difficult to form an even, smooth surface very problematic.
Polystyrene concrete, where polystyrene foam granules are used as filler, can be leveled more thoroughly, so this material can be used for both rough and finished floors.
Polystyrene concrete, having good strength, has a very low density(200-300 kg/m3), thereby providing high-quality thermal insulation floor surface. This one is awesome polymer material for pouring the base of the floor, it is easy to prepare with your own hands using a regular concrete mixer.
Semi-dry screed
To construct the base of the floor using this technology, which is also called German, a cement-sand mixture with a limited water content is prepared. In addition to the main components, the composition includes plasticizers, polymer additives and fibrous components. To prepare the working material, professionals use special mixers. However, as practice shows, a regular concrete mixer is also suitable for these purposes. So, if you wish, you can prepare such a mixture with your own hands.
The technology for laying semi-dry mixtures is somewhat different. The prepared material is scattered onto the surface not over its entire thickness at once, but layer by layer, while being compacted. When the layer exceeds the level of the beacons, the excess is cut off with a rule and smoothed out with it. You can see how they work with the semi-dry mixture in this video below, which shows not only the process of forming a horizontal surface, but also its finishing. In the video, smoothing of the main part of the screed surface occurs mechanically. This is usually done over large areas. This can also be done manually (using a metal grater) with the same result. It will just take a little longer.
A screed made using the technology demonstrated in the video has a number of advantages compared to classic liquid pouring of concrete. The following advantages can be highlighted:
- the surface is absolutely flat, that is, suitable for laying any type of floor covering without additional leveling;
- the base does not require strengthening of the top layer (topping), does not form cement dust and does not wear out;
- the technological break in work associated with the setting of the screed is much shorter, as well as the period of drying and complete crystallization of the binder;
- There is little shrinkage of the material during maturation, so the risk of cracking or delamination is negligible.
Important! The base of the floor, made with semi-dry mixtures, is much stronger than classical concrete pouring due to the compaction of the material, which is part of the technological process. Thanks to this, voids, air bubbles and other formations that reduce strength and are characteristic of ordinary concrete or liquid cement-sand mortar are not formed.
Packaged screed mixtures
By doing extensive work, especially in new buildings, on-site prepared mixtures from individual components or ready-mixed concrete, made industrially and delivered by concrete truck, are used. If the scale is not so large, especially since the screed is installed somewhere in the apartment on the floors, it is much more convenient to use ready-made packaged mixtures (usually 25 kg bags).
The finished dry substance contains a polymer-cement binder component, often with the addition of fibrous components, and a sand filler made up of grain of different fractions. The working solution can be prepared either with a concrete mixer or with a construction mixer, according to the proportions that each manufacturer indicates on the packaging. The maximum and minimum thickness of the poured layer, setting and full maturation time and other characteristics of such materials are also always indicated. This makes ready-made mixtures convenient, especially for those who are making screed for the first time with their own hands. You can see the technology for working with such materials in the following video.
Self-leveling solutions
Self-leveling floors are ready-made gypsum-based mixtures that are capable of self-leveling, that is, self-distributing over the surface strictly horizontally and forming a flat, smooth surface. Self-leveling mortars are durable, which is why a minimum layer of about 10 mm is allowed. Such compositions are convenient to use for leveling concrete or cement-sand foundations with minor differences in the horizontal plane. This allows you to obtain a surface ready for laying any floor coverings, which quickly gains operational strength, significantly reducing the technological interruption when performing DIY repairs. How professionals use self-leveling mixtures is demonstrated in this video
Checking the base for clearance is carried out only to determine its unevenness, and not the slope. Floors can be not only horizontal, but also inclined, for example, on ramps, in showers, etc. Slopes are checked by “shooting” with a level or laser level, and unevenness (lumpy) of the base is checked by the “through the light” rule.
The lumen is checked in two ways.
Method one. The two-meter rule is installed on the floor surface in an arbitrary place, the worker kneels down, bends down and looks to see if there is a gap between the bottom plane of the rule and the base of the floor. If there is a gap, it is measured with a tape measure; a gap of 2 mm is acceptable. If more, then the base needs to be leveled. After the first check for clearance, the rule is shifted approximately 1000 mm to the left, then the same distance to the right and the clearance is checked again. In this way, several checks are made, for example, in the center of the room and at all walls. This method of checking the base is not very accurate, since the rule may end up on a hillock and begin to sway, but it is sufficient for a high-quality floor installation (Fig. 29).
Rice. 29. The first way to check the floor for light
Method two. Under a high-quality floor covering, we attach the same thickness to the rule at both ends wooden spacers. Thus, as a rule, even if it hits the hillocks, it will not swing, as it did in the first method. In this case, there is always clearance under the rule, and the curvature of the floor is calculated by measurements. Let's consider this method using the example shown in Figure 30.
Rice. 30. The second way to check the floor for transmission In the first case, the rule fell on the slopes of two hillocks; measuring the distances and calculations show that the base is quite flat and the height difference does not exceed ±2 mm. However, shifting the rule to the right or left (on bumps or in pits) shows irregularities already of +4 mm and -4 mm, which indicates the inadmissibility of using this base, since the permitted tolerances with any sign should not exceed 2 mm. Conclusion: the base needs to be leveled, despite the fact that the first measurement showed acceptable gaps.
According to Russian regulatory documents, the clearances between the screed and the rail should not exceed for:
- linoleum coverings, PVC tiles, textile carpet materials, piece parquet, parquet boards and panels, laminated flooring - 2 mm;
- coverings made of ceramic tiles, artificial and natural stone, mosaic-concrete slabs and mosaic mixture - 4 mm.
When purchasing flooring, always read the instructions and pay attention to the tolerances for unevenness of the base that the manufacturer of the flooring allows. It can be one, two, or three millimeters. Do not try to experiment and exceed the tolerances, even if you are not very interested in the perfect flatness of the floor, as violating the tolerances can lead to the destruction of the floor covering. For example, gaps in laminated floors that are larger than permissible will lead to a “break” of the floor at the joints.
Often, laying floor coverings and installing floors is done based on personal considerations, as well as expediency. But in fact, the design of floors and screeds should be based on a regulatory document that regulates the main technological processes. These documents are constantly used in the construction and design of buildings, but also House master must know the requirements set out in SNiP, because floors and screeds have a serious scope of requirements. Let's look at the most basic ones.
Floor screed according to SNiP
When it is necessary to prepare a concrete slab for a decorative floor covering, a floor screed is done. There is also a separate section for this in SNiP. If you familiarize yourself with the requirements, recommendations and standards, the result is the most stable and durable foundations.
Naturally, these standards are mandatory only for capital construction projects, but many are guided by them for home repairs.
Determining the screed function
If you look at the building regulations, a floor screed is a layer of mortar based on sand and cement, which is poured onto the base base. The main function of the screed is to form the most even base for the future finishing floor covering. The standards also provide for such a floor screed device to ensure a sufficiently high strength of the base against mechanical damage. SNiP specifies all the necessary standards.
Documentation
Subfloors should be designed according to special regulatory documents. Previously, SNiP 2.03.13-88 was considered the main document on rough concrete foundations. However, despite the fact that floor installation techniques in residential buildings have not changed, new materials and construction technologies, because the standards have changed.
Today the document SP 29-13330-2011 is in force. It updates the edition of the standards for flooring.
Requirements for the screed device
The requirements for floor screed, which are provided for in SNiP, allow you to obtain quality foundation. It is better to use these standards and requirements in the project for your apartment.
Thus, the minimum layer thickness when laying on a concrete base is 20 mm. If an additional insulating layer or soundproofing materials are laid, the thickness will be 40 mm. If a pipeline or other communications are installed in the screed, then the layer above the communications should be no less than 20 mm.
If compressible materials are used as heat or sound insulation, then the strength of the sand and cement fill is increased. It should be no less than 2.5 MPa. In this case, the thickness of the screed should prevent any deformation.
The minimum strength of the solution is 15 MPa, and if the decorative finishing layer is a polyurethane self-leveling floor, then the strength is made equal to 20 MPa.
If a self-leveling mixture is used to form smooth surfaces, then the thickness of the layer of this coating should be no less than 2 mm.
To control the plane of the coating, the regulations provide for the use of a rule. If it is necessary to check the geometric characteristics of the layer, use a tool 2 m long.
According to SNiP, it is allowed if the floor screed has deviations, but not more than the specified values:
- For parquet, laminate, linoleum and self-leveling floors on polymer mixtures, 2 mm by 2 m is allowed;
- For other types of coatings, up to 4 mm per 2 m is allowed.
When monitoring the surface, deviations from these standards are leveled out first, since they have a great influence on how well the finishing floor covering will be laid.
Technologies and general requirements for the basic foundation
Before laying the sand-cement layer, prepare the base. IN regulatory documents There are special recommendations for this.
Thus, the foundation should be planned according to the profile or marks in the design documents. If it is necessary to add soil, the layer is compacted and leveled as much as possible. A mixture of sand and gravel is often used as backfill.
If floors are laid on the ground, then work can only be done when it thaws. If the soil surface is weak enough, replacement or additional strengthening is required. It is recommended to strengthen with crushed stone with a fraction of 40-60 mm. In this case, the strength must be no less than 200 kgf/m2.
If as a base concrete slab, then it is cleaned of debris and dust. Then the surface is washed with water. If there are joints between the slabs, they are filled cement-sand mortar. In this case, the filling depth must be no less than 50%. For these purposes, a solution of grades 150 or more is used.
Materials
- Sifted sand;
- Cement from M150 for industrial premises and M300-400 for residential premises;
- Gravel and crushed stone with a fraction from 5 to 15 mm. The strength indicator should be from 20 MPa.
Reinforcement
Floor screed reinforcement is used to give the structure greater strength. SNiP recommends the following materials:
- Wire mesh with a cell of 100×100 or 150 mm;
- Mesh made of polymer materials;
- Frame made of twigs;
- Fiber reinforcement – fibers of steel, polypropylene, basalt.
This procedure is necessary where the height of the screed is more than 40 mm. For residential premises where there is no provision high load on floors, screeds up to 70 mm are not reinforced.
The laying of reinforcing materials is carried out at the preparatory stage. To ensure that the reinforcement fits correctly, special plastic supports are used.
Screed pouring technologies
The base base is processed according to all the previously described recommendations. Then you need to treat the surface with primers. After the primer composition has sufficiently polymerized, a cement mortar is prepared in a ratio of 1:3, where 1 part is cement and 3 parts sand.
If sound or heat insulating materials, then a damper tape with a thickness of 10 to 25 mm is installed around the perimeter of the room. Also, beacon slats are installed on the floor, and then the screed is poured.
The floor will be ready no earlier than in 24 hours. You should not walk on the base with your feet. If there is a lot of time, it is better to give the screed 30 days. Then you can begin sanding and laying the topcoat.
Object of inspection: concrete screed
Address of construction examination: Moscow
The purpose of the construction examination: assessment of the quality of the completed construction and installation work on screed installation for compliance with the requirements of the current regulatory and technical documentation (screed examination).
Technical control equipment used at the facility: laser rangefinder DISTO classic/lite, Canon digital camera, metric tape measure GOST 7502 - 80, Pulsar ultrasonic tester.
During the inspection and drawing up the expert opinion, regulatory documents were used.
General provisions for determining quality
A technical inspection of the Customer's facility was carried out with the aim of making an examination of the screed. The basis for conducting a technical inspection is the Construction Expertise Agreement, which specifies the purpose of the inspection and the list of work that needs to be performed. When carrying out the inspection work, the data obtained was taken into account and defects were photographed. The survey results that served as the basis for this conclusion are given as of October 5, 2010.
Diagnostic examination
Inspection of building structures of buildings and structures is carried out, as a rule, in three interconnected stages:
- preparation for the examination;
- preliminary (visual) examination;
- detailed (instrumental) examination.
In accordance with the requirements of SP 13-102-2003 clause 6.1, preparation for surveys involves familiarization with the survey object, design and executive documentation for the design and construction of the structure, with documentation on the operation and repairs and reconstruction that took place, with the results of previous surveys.
The expert carried out an external inspection of the object, with selective recording on a digital camera, which complies with the requirements of SP 13-102-2003, clause 7.2. The basis of the preliminary examination is the inspection of the building or structure and individual structures using measuring instruments and instruments (binoculars, cameras, tape measures, calipers, probes, etc.).
The measurement work was carried out in accordance with the requirements of SP 13-102-2003 clause 8.2.1 The purpose of the measurement work is to clarify the actual geometric parameters of building structures and their elements, to determine their compliance with the design or deviation from it. Instrumental measurements clarify the spans of structures, their location and pitch in plan, dimensions cross sections, height of premises, 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 load-bearing structures and junction points of structures and their elements.
Classifier of the main types of defects in construction and the building materials industry
- Critical defect(when carrying out construction and installation works) - a defect in the presence of which a building, structure, part thereof or structural element are 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 must be unconditionally eliminated before the start of subsequent work or with the suspension of work.
- Significant defect- a defect, the presence of which significantly deteriorates performance characteristics construction products and their durability. A significant defect must be eliminated before it is hidden by subsequent work.
In this case, a defect is every single deviation from design solutions or failure to comply with regulatory requirements.
The expert carried out a diagnostic examination of the facility to determine the quality of construction and installation work performed in accordance with the requirements SNiP. The examination was carried out using the method of measuring quality control.
When assessing the quality of construction and installation work performed on the device, the following was established:
When tapping the coating concrete screed Changes in the nature of the sound were recorded on numerous areas of the floor surface. This fact indicates a poorly executed base, as a result of which there is no adhesion of the top floor covering to the base.
Construction expert commentary
According to “Resolution of the Government of the Russian Federation N 1025 of August 15, 1997 On approval of the Rules consumer services population in 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 contractor 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 “Basic repair work basements, cellars, floors of all types, roofs, exterior cladding or interior walls various materials, plastering of walls, ceilings, columns, filing of ceilings, as well as tiling, painting, wallpaper, glass, insulation work must be carried out in accordance with SNiP 3.04.01.”
Changes in the nature of the sound revealed during the inspection when tapping the floor covering 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 rigid tile materials with underlying floor elements tapping should not change the character of the sound.”
The basic 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 rod should not exceed, mm, for: earthen, gravel, slag, crushed stone, adobe and paving stone coverings - 10 asphalt concrete coatings, over a layer of sand, end surfaces, cast iron plates 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 mastic, end coatings, cast iron and steel plates, bricks of all types - 4 coverings made of cement-concrete, cement-sand, mosaic-concrete, asphalt concrete, ceramic, stone, slag-and-sand slabs - 4 polyvinyl acetate, plank, parquet and linoleum coatings, rolls based on synthetic fibers, polyvinyl chloride and super-hard fibreboards - 2 | |
The ledges between adjacent coating products 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-and-sand slabs - 1 plank, parquet, linoleum, polyvinyl chloride and super-hard fiber boards, polyvinyl chloride plastic - not allowed | |
Recesses between coverings and floor edging elements - 2 mm | Measuring, at least nine measurements for every 50-70 m2 of coating surface or in one smaller room, acceptance certificate |
Deviations from the specified slope of coatings - 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 on a conventional grid with a cell size of at least 50x50 cm, acceptance certificate |
Gaps should not exceed, mm: between the boards of the plank covering - 1 between parquet boards and parquet panels - 0.5 between adjacent strip parquet plans - 0.3 | Measuring, at least five measurements for every 50-70 m2 of coating surface or in one smaller room, acceptance certificate |
Gaps and cracks between baseboards and floor coverings or walls (partitions), between adjacent edges of linoleum panels, carpets, roll materials and tiles are not allowed | Visual, entire floor surface and joints, acceptance certificate |
The coating surface should not have potholes, cracks, waves, swelling, or raised edges. The color of the coating must match the design | The same, the entire floor surface, acceptance certificate |
When examining the floor, numerous cracks were recorded in the screed with an opening width of up to 2 mm.
Expertise comment
This fact is a violation of the requirements of SNiP 3.04.01-87 “Insulating and finishing coatings”, according to which:
Requirements for the finished floor covering
4.43. The basic requirements for finished floor coverings are given in Table 25.
Table 25
Expert opinion
The presence of cracks indicates a loss of strength and structural integrity of the floor.
When checking cracks using an ultrasonic tester, the maximum depth their occurrence is 35 mm.
Expertise comment
The revealed value of the crack depth indicates the absence of solidity of the floor.
When examining individual exposed sections of the floor screed, it was revealed that the soundproofing layer was filled with expanded clay of a 15 mm fraction.
Expertise comment
Identified granularity of bulk soundproofing material- 15 mm, is a deviation from the requirements of “SNiP 3.04.01-87 Insulating and finishing coatings, clause 4.20”, according to which the size of bulk soundproofing material should not exceed 10 mm.
SNiP 3.04.01-87 Insulating and finishing coatings
4. Floor installation General requirements soundproofing device
4.18. Bulk soundproofing material (sand, coal slag, etc.) must be free of organic impurities. The use of backfills made from dusty materials is prohibited.
4.19. Gaskets should be laid without gluing to the floor slabs, and slabs and mats should be laid dry or glued with bitumen mastics. Soundproofing pads under the joists must be laid along the entire length of the joists without breaks. Tape spacers for prefabricated screeds sized “for a room” should be located in continuous strips along the perimeter of the premises close to the walls and partitions, under the joints of adjacent slabs, as well as inside the perimeter - parallel to the larger side of the slab.
4.20. When installing sound insulation, the requirements of Table 18 must be met.
Table 18
Technical requirements | Limit deviations | Control (method, volume, type of registration) |
The size of the bulk soundproofing material is 0.15-10 mm | Measuring, at least three measurements for every 50-70 m2 of backfill, work log |
|
Humidity of bulk material backfill between joists | No more than 10% | |
Width of soundproofing pads, mm: under logs 100-120; for prefabricated screeds sized “per room” around 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 soundproofing pads inside the perimeter of prefabricated screeds sized “per room” is 0.4 m | The same, at least three measurements on each prefabricated screed slab, work log |
The expert measured the speed of propagation of ultrasound in the floor screed structure to determine the average compressive strength, class and grade of concrete.
The measurements were carried out with a Pulsar ultrasonic tester, according to GOST 17624-87 “Concrete. Ultrasonic method for determining strength." The number and location of controlled sections on structures are established taking into account the requirements of GOST 18105-86 “Concrete. Rules for strength control."
Based on the measurements performed, the average strength of concrete was calculated, the grade and class of concrete compressive strength were determined.
The results are listed in Table No. 1.
Table No. 1
Spread speed ultrasound in areas | The closest concrete class in terms of strength for compression | Concrete grade by strength for compression |
|
According to the results of ultrasonic examination, the concrete strength grade was M 200.
Construction examination conclusion
Conclusion of a construction expert on screed inspection
Purpose of the survey: assessment of the quality of construction and installation work performed on screed installation for compliance with the requirements of current regulatory and technical documentation.
The quality of construction and installation work performed by the Contractor does not meet the requirements of regulatory and technical documents, namely:
The floor covering was installed in violation of the requirements of current regulatory and technical documents. According to the examination, these violations of regulatory requirements are a consequence of:
- failure to comply with work technology;
- lack of proper control over the work by the contractor;
As a result of violations of regulatory requirements, this coating cannot provide the designed load-bearing capacity. The fact that part of the floor covering is subject to changes in the nature of the sound when tapped (recorded during the survey) indicates the presence of voids in such areas.
According to the examination, areas where voids are identified are also susceptible to cracking, which can subsequently lead to complete destruction of the top floor covering.
Thus, the inspection found that eliminating the identified violations is not possible without partially dismantling the top floor covering in areas with cracks.
To bring the quality of construction and installation work into compliance with current regulatory requirements, it is necessary to eliminate the above-mentioned shortcomings.
To eliminate the shortcomings of the work performed with the screed, we recommend: contacting a contractor construction organization with the requirement to bring the quality of work performed in accordance with current regulatory requirements.
