1. Visual inspection.
If the surface has a "steely" shine, it means that the solution has an excessive "fat content", i.e. increased amount of cement. But of course, if you follow the screed care rules, this should not have fatal consequences. Further, there should be no cracks on the screed.
2. Checking evenness. It is necessary to check the evenness of the screed with a two-meter rail-rule or the level of the rule. It is necessary to apply the rule to the screed surface in different places, orienting it in different directions. According to quality criteria, the gap between the rule and the screed in any place should not exceed 4 mm.
3. Checking the slope of the surface to the horizon. You can check any quality level. The permissible value is considered 0.2%, but not more than 50 mm. For example, if you have a room length of 5 meters, the permissible deviation of the screed from the horizontal should be no more than:
(5 m \u003d 5000 mm)
5,000 / 100 * 0.2 \u003d 10 mm.
4. Tapping. Take a wooden block and tap the entire surface of the screed with its end. The sound from the blows should be the same over the entire area of \u200b\u200bthe screed, "hard", "ringing". If in some places you hear the sound "dull", "void" - it means that there are delamination of the screed from the base, then the screed is "bunching", which is unacceptable.
Each country has its own quality standards and these standards differ slightly among themselves. From the point of view of the customer, the comparison will not be in favor of the Russian SNiP.
And if the builders promise you "renovation", it would be better to ask them to indicate in the contract that the quality standards of all works must comply with the European DIN standard, and not the Russian SNiP.
If a defect is found, we recommend calling an expert. Determining the scale of a disaster and how to deal with it will require professional knowledge and experience. And of course, it's better to talk to the bunglers for a professional. In this case, the work of the expert will be paid by the culprit of the marriage.
If you want to figure out the situation yourself, you can advise you the following:
In a situation in which you yourself want to understand the situation without an expert, you will need to do the following:
Further all your actions must be documented!
If the quality standards are violated, they must be recorded on paper, and it is also desirable to photograph them. Moreover, if the builders refuse to sign a bilateral act, then it is necessary to call the attesting witnesses and act on the marriage independently.
With an uneven screed surface or with an unacceptable slope, it is necessary to oblige the builders, of course at their expense, to eliminate the marriage. It will be better if you apply a leveling compound, which must be applied in a thin layer so as not to increase the thickness of the screed.
If there are cracks in the screed, then it is necessary to "open up" the cracks, prime and cover with a thick cement mortar with BUTS (Non-Shrinking Cement) or cast resin. Well, if you have a lot of cracks, then the screed will need to be completely removed. And of course, much depends on the nature of the cracks, and in such cases it is better to invite an expert.
If there are voids in the screed, which are determined by tapping, you will need to remove the exfoliated areas, prime and then refill. It may be necessary to completely remove the tie, without inspection it is not determined.
Today, there are many ways to carry out work related to leveling the subfloor for further laying of floor coverings. The most common is the device of floor screed with various cement-based mixtures. This applies to both the filling of the rough leveling layer and the finishing screed. All work related to leveling the floor with cement mortars, even if they are 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. What technologies can be used to make a durable floor screed that meets the requirements of the floor, we will discuss further using the appropriate video materials, which will facilitate the perception of information.
Floor screed requirements
When performing work related to the device of supporting building structures, the importance of meeting their specific requirements should be taken into account. This also applies to floor screeds, both rough and finishing. Indeed, the durability of the floor materials, the laying of which will be done after, will depend on their strength. So it makes sense, before doing the work with your own hands, to familiarize yourself with some of the fundamental requirements set forth in the latest edition of SNiP, which must comply with a high-quality floor base. What technical parameters are spelled out in SNiP for cement floor screeds that are important for their DIY arrangement 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 of expansion joints on the floor map.
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 with reinforcing fibers included in the composition, deviations downward (at least 15 mm) are allowed. If there are pipe communications under the screed, the minimum layer is 40 mm, regardless of the characteristics of the mortar used.
The strength of the coating is difficult to determine without special technical means. Whether or not the basis meets these requirements, which are spelled out in SNiP, can only be determined indirectly. To be sure of the strength of the manufactured surface, the proportions and quality of the components used to prepare working mixtures should be observed and the technological sequence should be followed when arranging 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 overmoistening of the screed due to various reasons, as well as when pouring liquid mixtures to ensure proper hydration of the cement that is part of the mixture. This is necessary for high-quality crystallization of the binder during its maturation, which directly affects the final strength of the structure.
A screed made according to any technology is reinforced if its thickness exceeds 50 mm. This standard is spelled out in SNiP for rooms with a small and medium load on the floor surface, that is, residential. Reinforcement provides additional strength to the base of the floor and prevents cracking. Indoor screeds less than 50 mm can be reinforced under certain operating conditions (temperature differences over the underfloor heating system, for example). Rough cement bases do not need reinforcement, since the main load falls on the overlying finishing layer.
The technological floor plan, taking into account all the parameters of the screed, is developed when pouring 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 distance between them, and other technical information.
By creating a floor map, engineers agree on all the nuances so that the resulting surface meets the requirements specified in the SNiP for the structure in accordance with the expected loads and operational features. When arranging rough and finishing floor foundations in small areas, there is no special need to develop technological maps, since the work is not voluminous and not 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 a solution, the technological sequence of work, and the availability of visual information that can be gleaned from the video of the corresponding content. Moreover, when it comes to the manufacture of a finishing base from ready-made mixtures, it is assumed that manufacturers must ensure that their product meets the requirements of SNiP and other regulatory documents. To properly perform the laying of the screed, including the rough one, you just have to carefully read the manufacturer's instructions and do the work in accordance with the recommendations set out.
Basic technologies for screed devices with various mixtures
Among the technologies that are used today for arranging floor bases for various functional purposes inside residential premises, the main ones are the following:
- classic concrete pouring and its varieties;
- semi-dry screed according to German technology;
- production of a surface for laying floor coverings using ready-made packaged mixtures;
- finishing leveling with self-leveling liquid solutions.
Each of these technologies has its own priority area of \u200b\u200bapplication. When it is better to use it when installing the sub-floor with your own hands, consider further.
Concrete base and its varieties
Previously, there was no alternative to concrete, so screeds were made only from this material. Nowadays, concrete for a final screed inside a living space is used less and less. However, due to its low cost, concrete remains indispensable for rough casting, when thick leveling layers often have to be formed. Moreover, to form a rough base, a depleted solution with a low content of binders is used.
A concrete floor screed, the manufacturing technology of which is the best suited for a rough base, has recently begun to be equipped with modified materials, where light fillers with thermal insulation properties are used instead of heavy and cold crushed stone. The most used of them are expanded clay concrete and polystyrene concrete. The first one is used only for the formation of the rough layer, since the expanded clay granules are large in size, which makes it very problematic to form a flat, smooth surface.
Polystyrene concrete, where expanded polystyrene granules are used as a filler, lends itself to a more thorough leveling, so this material can be used for both subfloor and final floor.
Polystyrene concrete, having good strength, has a very low density (200-300 kg / m3), thereby providing high-quality thermal insulation of the floor surface. This chain-link polymeric subfloor grout material is easy to do-it-yourself using a conventional concrete mixer.
Semi-dry screed
For the device of the sub-floor using this technology, which is also called German, a cement-sand mixture is prepared with a limited water content. In addition to the main components, the composition includes plasticizers, polymer additives and fibrous components. Professionals use special mixers to prepare working material. However, as practice shows, a conventional 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 mixes is somewhat different. The prepared material is not scattered to the surface at once over the entire thickness, but in layers, while being compacted. When the layer exceeds the level of the location of the lighthouses, the excess is cut off by the rule and smoothed with it. How they work with a semi-dry mixture can be seen in this video below, which shows not only the process of forming a horizontal surface, but also its finishing. In the video, the smoothing of the main part of the screed surface occurs mechanically. This is usually done in large areas. This can be done by hand (using a metal float) with the same result. It just takes a little longer.
A screed made according to the technology shown in the video has a number of advantages over the classic liquid concrete pouring. You can highlight the following advantages:
- the surface is completely flat, that is, suitable for laying any type of flooring without additional leveling;
- the base does not need 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 less, as well as the period of drying and complete crystallization of the binder;
- material shrinkage during maturation is negligible, therefore the risk of cracking or delamination is negligible.
Important! The base of the floor, made with semi-dry mixtures, is much stronger than the classical pouring with concrete due to the compaction of the material, which is included in the technological process. Due to this, voids, air bubbles and other formations that reduce the strength and are characteristic of ordinary concrete or liquid cement-sand mortar are not formed.
Packaged mixtures for screed
When performing large-scale works, especially in new buildings, on-site mixtures of individual components or ready-made concrete made by an industrial method and delivered by a concrete truck are used. If the scale is not so large, the more the screed device takes place 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 sandy filler composed of grains of different fractions. You can prepare a working solution both with a concrete mixer and with a construction mixer, according to the proportions that each manufacturer indicates on the package. The maximum and minimum thickness of the cast layer, the time of setting and full curing and other characteristics of such materials are also always indicated. These ready-made mixtures are convenient, especially for those who make a screed for the first time with their own hands. You can watch the technology for working with similar materials in the following video
Self-leveling solutions
Self-leveling floors are ready-made mixtures on a gypsum base, which are capable of self-leveling, that is, they are independently distributed over the surface strictly horizontally and form a flat, smooth surface. Self-leveling mortars are durable, therefore a minimum layer of about 10 mm is allowed. It is convenient to use such compositions for leveling concrete or cement-sandy bases with minor differences in the horizontal plane. This allows you to get a surface ready for laying any flooring, which quickly gains operational strength, significantly reducing the technological break when doing DIY repairs. How professionals work with self-leveling mixtures is demonstrated in this video
The structure of building rules, which include SNiP for floor screed, is currently formed as follows: the basis is the federal law "On technical regulation" (No. 184-FZ of December 27, 2002). This is followed by the federal law "Technical Regulations on the Safety of Buildings and Structures" (No. 384-FZ of 12/30/2009).
Its norms are applied without fail, because they define conditions safe design, construction and operation of buildings and structures. Its provisions are of a framework, general nature. Clarification of the relevant parameters occurs through the publication and application of building rules or updating the old ones, adopted during the years of the existence of the USSR. At a certain stage, difficulties arose with understanding which SNiPs (currently referred to as codes of practice) should be used without fail. For this, on June 21, 2010, the Government of the Russian Federation issued, which approved the List of standards and building rules (in whole or in part), the application of which on a mandatory basis ensures the fulfillment of the requirements of the technical regulation. In addition, another list was approved by order of Rostekhregulirovanie (No. 2079 dated 01.06.2010). It includes rules and standards, the application of which to voluntary basis assumes compliance with the terms of the technical regulations.
Floor arrangement rules
The screed is an element of the overall floor structure. It is designed to create a flat and solid base for laying flooring. It perceives and distributes the loads that arise during the operation of the premises. In most cases, the course applies cement strainer... May 20, 2011 was put into effect updated the set of rules "SNiP 2.03.13-88 Floors" (see the order of the Ministry of Regional Development of Russia No. 785 of December 27, 2010). It replaced the previous rules, which were published back in 1988 (see).
By that time, a number of provisions of the previous SNiP of 1988 had already been included in the “mandatory” list approved by order No. 1047 (we are talking about sections 1, 2 (paragraphs 2.1-2.5, 2.6-2.9), 3-7 of the old rules). It is expected that during the transition period this list will be updated taking into account the new sets of rules (their content and structure). Up to this point, the old rules apply, since they are mentioned in the government order, i.e. new joint ventures have not yet canceled the old SNiP (see Letter of the Ministry of Regional Development of Russia dated 15.08.2011 N 18529-08 / IP-OG).
According to clause 1.1 of the joint venture as amended in 2011, the rules apply to cases designing floors. Production the works themselves on the manufacture of floors are carried out in accordance with SNiP 3.04.01 (see clause 1.4; in the text of the document, these rules are indicated without an index indicating the year of their adoption; now - 1987). These rules for the most part regulate the conduct of finishing work (determine, in particular, the types of finishes, as well as the associated runs). However, the provisions are not included in the list provided for by decree No. 1047, i.e. their observance is optional.
The provisions of the updated set of rules, normalizing individual indicators of screeds, are provided for in section 8 (old SNiP - section 5). In particular, the rules define:
- the appointment of screeds (clause 8.1);
- minimum layer thickness (clauses 8.2, 8.6, 8.7, 8.9);
- its strength;
- tolerances in terms of angular deviations (clause 8.13);
- conditions for the device of expansion joints (pp 8.14 and 8.15).
Requirements for flooring
According to clause 8.13 of SP 29.13330.2011, the clearance between the two-meter lath and the screed surface should not exceed 2 mm for coverings made of linoleum, parquet, laminated parquet.
In accordance with clause 4.24 of the old SNiP 3.04.01-87, the horizontal deviation of the screed should not exceed 0.2% (and in any case not more than 50 mm).
It should also be borne in mind that the structure of the floor must comply with the content of the sanitary rules, and in particular, ensure the sound insulation of the premises in due measure - in particular, prevent the propagation of impact noise. For this, technologies "" are used.
In a specialized section of our website, you can also familiarize yourself with the rules of the device - both the requirements and tolerances of a general nature, and the standards that determine the manufacturing technologies for certain types of leveling layers.
SNiP for semi-dry floor screed
Recently, the technology of mechanized production of screeds has become widespread in the market of construction services, which is called "semi-dry screed" in Russia. This method of leveling the base of the floor came to us from the countries of Western Europe along with the penetration of specialized mobile units designed for the automatic preparation of the solution and its supply to the work site.
There is no specialized SNiP for a semi-dry screed. The existing rules are applied on a general basis: for the design of floors - SP 29.13330.2011, and for their manufacture - the not yet updated rules 3.04.01-87, which regulate the conduct of work on the application of insulating layers.
The mandatory application of these rules is established on a general basis: only those provisions are mandatory that are listed in a special resolution of the government of the Russian Federation.
The article currently lacks reference to links on this topic.
- In recent years, the technology of mechanized floor screed, or, as it is also called, semi-dry screed... We talk about it in a separate article on our website. In preparation for its writing, we asked our engineers and foremen to summarize their experience in conducting these works directly in Moscow and the Moscow region.
Notes
No article notes found. We regularly edit dictionary entries. It is possible that additional materials will be posted on this site soon.
Cost of work: 600 rubles / m2material: 650 rubles / m2
- sand concrete
- plasticizer
- noise insulation PPU 2mm
- perimeter cutoff
In this article, we will tell you about the things that any customer who plans to perform a screed should know - both about the technology itself and about ways to avoid being deceived by careless builders.
One of the main requirements of a high-quality screed is a perfectly flat horizontal surface. How to determine the screed level?
Stage 1. Determine the horizontal level of the screed
The first thing in this business is to decide on a zero level. In the absence of laser devices, an ordinary water level is quite suitable for this purpose (it is also called a spirit level). The level used by carpenters is unacceptable for this purpose.
The zero level should be "beaten off" in all rooms at once, the height of the beating can be any, although the optimal level is 1.3-1.5 m above the floor level.
It is done this way: in the room, the first "beat" is made anywhere. With the help of the level, it is transferred to all other walls, both inside this room and in other rooms. The result is marks at the same level relative to the “ideal sex” (which in fact does not exist). The marks within each room are connected in series with each other with straight lines. This will be our zero level, against which we will work. We do not think it is worth saying that the quality of the entire screed will depend on the accuracy of the "beating" of the zero mark. Step 2. Identification of the maximum level of the available floor and the height difference
We need this in order to correctly select the level of the screed. It should not be higher than the highest point of the floor level. Also at this stage we can roughly figure out how much material we need for work.
To do this, we measure the height from the zero level to the real floor. We do this as often as possible - the thicker the marks are, the better the result will be. In the course of measurements, we make marks on the wall, next to which we write the value. The lower the value, the higher the point is and vice versa.
For example, the minimum value is at 1.19 m, and the maximum is 1.29 m.Then the height difference will be 10 cm.If you have obtained a much more modest value of the difference, keep in mind: it is inappropriate to make a screed thinner than 30 mm, so how it will very quickly become covered with cracks and begin to crumble. An exception can be made only in one case: a special self-leveling type compound will be used for leveling. The minimum and maximum thickness values \u200b\u200bin this case are indicated on the packaging by the manufacturer himself.
Sometimes situations arise when different levels of screeds are needed in the same room in different rooms, which is explained by different types of coatings that they plan to use in the future.
For example, it is often in the same apartment that parquet is laid in the living rooms, and tiles are laid in the bathroom and kitchen. Parquet laying will require serious calculations, since the parquet itself is successively several layers of different materials. For example, the total thickness of a parquet can be calculated as follows:
0.2 cm of mastic (glue) + 1.3 cm of plywood + 0.1 cm of parquet glue +1.5 cm of parquet \u003d 3.1 cm.
We remove 1 mm for scraping, we get 3 cm.
For ceramic tiles, the calculations will be as follows:
0.6 cm per glue + 1.1 cm tiles \u003d 1.7 cm.
Consequently, in the places where parquet and tiles are joined, the difference will be 3 cm - 1.7 cm \u003d 1.3 cm.
These are theoretical calculations, but in practice one should add another 1-2 mm to this number. It should be borne in mind that the thickness of the parquet always remains constant, but the thickness of the tiles can be increased due to the thickness of the adhesive base.
Let's talk about the quality of the materials required to create a screed. Most often, builders use a mixture of cement and sand for this purpose, which is sold ready-made in bags. Sometimes cement and / or plasticizer can also be added there.
Always ask the builders what kind of mixture they plan to use for the screed in your premises. Please note that in pursuit of a cheap mixture, you can get a low-quality result, and buying a mixture on the market at the first available outlet can nullify all their efforts. Also, different mixtures can be designed for different construction work.
When buying a mixture, pay attention to its color. The indicator of a high-quality cement mixture is a light gray color without impurities. Red and yellow shades of the mixture are given by an excessive content of sand or clay.
If you bought a high-quality, proven mixture, there is no need to add cement to it, as this will negatively affect its properties. The same applies to PVA glue - instead, it is necessary to add plasticizers in the quantities recommended by their manufacturers.
Stage 4. Preparing the surface for the screed
The screed requires preliminary surface preparation. First, it must be cleaned of dirt, dust, moisture and cement mortar (if any). Detachments should be removed, uneven surfaces should be leveled with a thick cement mortar (ideally, if it is Non-Shrinking Cement - BCC).
To remove dust, it is best to use a construction vacuum cleaner; in its absence, thorough sweeping with an ordinary broom is also suitable. After that, the floor is primed. At the junction with the walls, a waterproofing gasket is placed in the form of a roofing material tape.
If the builders recommend that you do a complete waterproofing of the floor, this is not correct. Firstly, such a layer will impede adhesion, which will reduce the strength of the screed. Secondly, if your apartment is flooded by neighbors from above, all the water will remain in your room. It is better to pay attention to the cracks and get rid of them before the screed.
Stage 5. Putting beacons
Beacons are called guides, with the help of which the screed will be aligned one level at a time. If installed correctly, the screed will be even over the entire floor surface. Dense and rigid materials - pipes or profiles - are used as beacons. The installation method can be different: someone prefers to make small indentations in the solution, someone uses a screw fastening. The main requirement for an already installed beacon is its rigid fixation.
The installation of the lighthouses should be done so that they are parallel to each other, and between two adjacent lighthouses it was possible to support a rail with which the solution will be leveled.
Where the screed drops will be maximum, plywood formwork can be used, which will prevent the penetration of material from one area of \u200b\u200bthe screed to another.
Stage 6. Preparing the mortar and filling
Today, few builders are engaged in manual preparation of the solution - more often small concrete mixers come to the rescue. And this affects the quality of the solution well - the concrete mixer mixes it more thoroughly.
If, nevertheless, the builders stir the solution by hand, pay attention that they do not add more water to the solution than it should be according to the instructions - so they can try to simplify their task and stir the solution more quickly. This will make the tie less durable and you will be the loser.
To determine the optimal liquid content in a solution, fairly simple instruments are used. Professional builders with extensive experience can cope without instruments, "eyes", and they do it quite accurately. Outwardly, an ideal solution should look like a thick dough. There should be no lumps in it, it should not crumble or, conversely, excessively spread over the surface.
Fresh solution must be used within 60-90 minutes. You cannot leave the solution for later, pouring a layer of water over it. Pouring is done in one pass; several stages within one room are unacceptable.
Tip: when making a screed, pierce the solution as often as possible with a thin metal rod. This will help prevent air-filled voids from forming.
Stage 7. We take proper care of the screed.
Improper care of a fresh screed is the reason for a large number of defects, although in fact the rules for care are very simple. In the room in which the screed has just been made, it is necessary to maintain a high level of humidity for 7-10 days. This is required so that the solution does not just dry out from dehydration, but it hardens. If the surface dries, it will be difficult for deeper layers of mortar to do this.
To prevent premature drying of the screed, it is moistened with plain water several times during the day. On the third or fourth day, the lighthouses are taken out, and the depressions remaining from them are covered with fresh solution. After that, the screed is covered with foil and left so for 12-14 days.
Haste in this matter can be disastrous - it is better to wait a few days longer than to redo all the work from the beginning.
Stage 8. We accept the work of builders.
The result can be assessed in several ways.
1. Visual assessment. A high-quality screed looks like a flat surface of the same color throughout its entire area. It should not shine or have cracks.
2. Checking the level. Reiki rules are used for this purpose. It is applied to the screed in several areas of the room. According to building codes, the maximum discrepancy between the rule and the screed should not exceed 4 mm.
3. Determination of the slope in relation to the horizon. Any level can be used for testing. A value less than 0.2% is within the normal range, but not more than 0.5 cm (for example, if the room is 4 meters long, the deviation should not exceed 8 mm).
4. Tapping. Perform with a wooden block and listen to the sound. On the entire surface, the sound should be the same - sonorous. A dull sound signals the presence of voids.
In Russian construction standards, the quality of the screed device is regulated by SNiP 3.04.01-87. In Europe, they use the DIN 18560 standard. Both standards have a number of discrepancies, so if the builders guarantee you to make a European-quality repair, then you must evaluate the quality of the screed according to the second standard, otherwise it will be a gross violation of your agreements.
If a defect is found, it is better to call an external specialist for assessment, since determining the level of damage requires experience and practical training. It is logical if the work of this specialist will be paid for by builders who have performed their work poorly.
If you still want to follow through on your own, take these tips:
- record all actions and agreements on paper, providing them with bilateral signatures;
- if possible, photograph defective areas.
In the case of an obvious defect, oblige the builders to eliminate it at their expense. This can be done with a self-leveling compound - not the cheapest way, but quite suitable for the builders to realize their guilt and pay in full for it. If you doubt that the people you hired will be able to cope with this task, hire another team and pay for their work at the expense of the first.
If there are cracks in the screed, they are primed and covered with BUTS. If there are a lot of cracks, the entire screed will need to be removed and redone. If there are voids in the screed (revealed by tapping), the upper sections are peeled off, removed and filled with the composition again.