- a rough coating that allows you to level the building base, mask defects, raise the floor and improve the sound and heat insulation of the room. This design is performed different ways, including using a concrete solution. There are several types of similar materials and, in order to make the right choice, it is recommended that you familiarize yourself with the properties of each product. Lovers who equip the screed on their own are advised by the masters to study the technology for making such a rough coating.
There are several types of concrete floor screed, depending on the method of forming the rough coating:
There are several types of solutions for arranging a concrete screed:
To prepare such a solution, cement and sand are used in proportions of 1: 3. To knead a quality product, it is recommended to use quarry sand. This material provides the strength of the solution and protects the material from cracking and the formation of other defects. Before mixing the product, it is recommended to sift the sand through a metal sieve with fine meshes. Next, cement and sand are combined and water is added so that a composition of medium density is obtained. The liquid solution shrinks after solidification and does not have sufficient strength. Such a product also does not level the surface, since it will not be possible to distribute the product using the rule due to the liquid consistency. If you make the composition too thick, then the material will not be distributed over the surface. For this reason, it is important to add enough water to create a liquid solution. Certain standards have been established for the ratio of liquid and cement-sand composition. However, such proportions are applicable for the arrangement of reinforced concrete pavements on an industrial scale. For home furnishing of the screed, it is recommended to be guided "by eye". Usually, masters take a liter of water for 5 kg of the mixture. It is important that the water is clean. This affects the quality of the screed. Do not use technical liquid, since such water contains oils and other foreign substances. A concrete mixer is used to mix the product. After that, a solution is obtained that is easily distributed over the building base, creating a reliable support without air voids.
In order not to independently select the proportions of materials for the preparation of the solution, it is recommended to use ready-made dry mixes for the screed. In such products, the required amount of each element is optimally selected, and the exact amount of water required to mix the solution is indicated on the packaging.
Ready-made mixtures have the following advantages over self-prepared formulations:
The only drawback of ready-made dry mixes in comparison with the material prepared independently is the high cost.
To make your own floor screed, it is recommended to adhere to the base pouring technology.
Zero-level concrete floor helps to flatten the screed by correcting surface differences. To make the markup, you need laser level... Since this is an expensive device, it is recommended to rent the unit, which will save a significant amount of money. You can also use a water or building level.
To make the markup, proceed as follows:
The minimum point value is the maximum height of the parcel. After setting the zero level, the screed height is calculated:
Before performing the screed, the building base is prepared. The preparation algorithm depends on the type of surface. If the screed is made for a private house, which stands directly on the ground, they act as follows:
The building base in the apartment is prepared as follows:
After that, the screed is performed.
In order to evenly distribute the solution over the surface, beacons are placed. Before fixing the guides, make the appropriate markings:
After that, the profiles are installed directly. They do this in several ways, but most often they use self-tapping screws:
To prepare a solution using a concrete mixer, proceed as follows:
If you use an industrial mixer or a drill with a mixer attachment, then proceed as follows:
Algorithm for pouring a building base with concrete:
After pouring the solution, the beacons are dismantled. To do this, wait for the mixture to set and remove the guides, carefully stepping on the building base. All voids are filled with a solution. The material is spread over the surface with a trowel, removing excess mixture. Take a break of 28 days. During this time, the material finally solidifies and gains strength. For several days after pouring, the surface is sprayed with water to prevent cracking. After the material has dried, the surface is sanded and a floor decorating coating is laid.
To extract the mortar from a concrete mixer, professionals recommend equipping a gutter. This design will direct the mixture to the right place and prevent contamination of the device.
Professionals also recommend raising the mesh reinforcement over the building base. They do it this way - a mesh is laid on the surface, a small amount of solution is placed, after which the reinforcing material is slightly raised so that the composition is distributed between the cells, lifting the mesh. This will protect the product from displacement during mechanical loading on the surface.
The video in this article demonstrates the rules for arranging a concrete screed.
The concrete screed is a durable rough surface. This element of the floor structure helps to improve the sound and thermal insulation performance of the room.
The most reliable and durable base for flooring is a concrete screed. It has high performance characteristics such as strength, wear resistance, resistance to mechanical stress. In addition, the screed helps to hide floor irregularities and other defects. Due to this, it is often used for flooring in residential buildings and industrial facilities.
In order to create a high-quality screed, it is necessary to approach its device comprehensively, use only high-quality materials and follow the technology.
The materials used for the screed can be:
The choice in favor of any material is made depending on what kind of floor covering will be the finish.
At overhaul premises or during the construction of a new building, the screed is made only of cement-sand mortar or aerated concrete.
At the same time, it is preferable to cement-sand mortar, if the screed is performed at home, without specialized equipment.
At cosmetic repair and replacing the floor, leveling compounds can be used, and this will be enough.
Concrete screeds differ in what types of structures they have, methods of installation and performance.
Screedson a related basis
With this option, the screed is poured onto the base, which is pre-cleaned, prepared and primed. Such preparation helps the screed to better bond with the substrate, and therefore it will better withstand high loads in the future.
The quality of operation will depend on how humid it is in the room. Such a screed must be arranged on a dry floor slab.
Screedson a separating base
The device of such a screed assumes that a layer of waterproofing will be previously laid on the base. For this layer, roll, coating or paint waterproofing is used, such as polyethylene film, bituminous mastic, roofing material. Waterproofing does not allow moisture to enter the upper layers of the floor. The height of the screed in this version should be 32 millimeters. A screed on such a basis has high waterproofing characteristics, but at the same time it is not very strong and wear-resistant. It is used mainly for outbuildings and technical premises, where there is high humidity.
Screedson an insulating base
Such a screed is used to create a base that has high performance in operation. Most often it is used to create a base for underfloor heating, where high waterproofing and heat protection are required. In this version, a heat-insulating layer is placed under the screed, and it is poured independently of other layers. Its thickness is 48-55 millimeters, and for proper operation, additional reinforcement is necessary. Such screeds are used in the floors above the basement, basement or on the first floors in a residential or public building.
Screeds on a reinforced base.
In order to create such a screed, a metal mesh or fiberglass is used.
- for the screed device, take a fine mesh, with a mesh size of 4-5 centimeters.
The mesh is mounted using special props on the base of the floor. Its use improves the performance of the floor. But at the same time, it oxidizes and collapses, which can lead to cracks in the screed.
Fiberglass- this material began to be used in order to increase the reliability of concrete screed. Thin microfiber is made from polymer granules by extrusion and modification. It is flexible, resistant to deformation and damage, economical and easy to install.
According to the number of layers, concrete screeds can be single-layer or multi-layer.
Before performing the basic work on the screed device, you need to decide what materials and tools you may need.
Substrate preparation - for the screed, it is necessary to thoroughly clean it from dust and dirt using a broom or, if available, a construction vacuum cleaner.
It is better to moisten the surface a little before cleaning so that less dust is released into the air.
After all the dust has been removed, it is necessary to carefully examine the base for irregularities, cracks, and height differences.
beacons are usually used to assess floor differences. They are installed throughout the room, and usually these are screws screwed into the base.
Threads are pulled between them, which form a network along the floor of the room. This will be the zero level, which you need to focus on when further work Oh. A lot of beacons will allow you to identify all the unevenness of the floor.
Screed preliminary layer - if there are strong irregularities and drops of more than three centimeters on the floor, then it is necessary to pre-fill the floor with cement of the M150 or M200 brand.
Surface priming - after installing the lighthouses and slight differences in the floor, or with significant differences after the preliminary layer has dried, a primer must be applied to the base. This is done so that the screed gets good adhesion to the base.
Thermal insulation and waterproofing - these layers are laid in the case when they are necessary. Waterproofing is used most often film or roll.
Waterproofing sheets are laid with an overlap relative to each other, and overlapping the walls. The joints between the sheets can be treated with a sealant. If a coating waterproofing is used, then the joints of walls and floors, corners, heating pipes and floor height differences, such as steps and podiums, are coated with it.
Expanded clay or expanded polystyrene sheets are used for the thermal insulation layer. The sheets are laid on the base, the joints between them are fastened with tape. Expanded clay is poured evenly onto the base and compacted.
Screed reinforcement - to strengthen the screed structure, use a reinforcing mesh. It is laid around the perimeter of the room so that there is space between it and the base.
Fiber is also used for reinforcement, which is added to the composition when kneading.
first, in a large container, sand and cement are kneaded, in a ratio of three to one. Then water is added to the mixture at the rate of one liter per 5 kilograms of the mixture. The mixture is stirred with a metal spatula until all lumps are removed. After that, it is interfered with with a construction mixer or a drill with a special nozzle for about 5 minutes, allowed to settle a little and stirred again for two minutes. The consistency of the finished mixture should be such that when squeezed in the palm of your hand, it does not spread, it is dense and viscous.
Filling the screed - the laying of the mixture begins with a shovel or scoop from the edge of the floor, from the far corner, in order to prevent the waterproofing layer from sliding, and gradually move to the middle. The mixture is laid a little more so that it overlaps the top of the lighthouses, and then it is leveled as a rule, removing the excess. If grooves form in the coating, add a little mixture and level again. After the mixture has set a little, the beacons are removed. And when the screed is completely dry, the holes from the lighthouses are sealed with the same mixture, focusing on the level of the already finished screed.
During the installation of the screed, it is periodically moistened to prevent cracking.
A high-quality screed creates a good base for subsequent floor covering, making it strong and durable.
You can perform work on its device at home, you just need to follow the technology of work and show care and thoroughness.
The concrete subfloor is currently perhaps the most widespread both in residential and industrial construction. It is suitable for almost any topcoat or, after appropriate processing, can be used independently. Its main advantages, subject to the casting technology, are high strength, resistance to destruction, durability of use. It is not surprising that when conducting private construction or when renovating an apartment, in the overwhelming majority of cases, homeowners choose exactly this technology for arranging the floor.
Is it worth inviting construction specialists, or is a do-it-yourself concrete floor screed quite an affordable process for the average home owner? This publication is devoted to the answers to these questions.
Concrete floor screeds may have different design, be performed using slightly different technologies and intended for different purposes.
- They can be single-layer, that is, poured simultaneously to the entire design height. This is usually used in industrial, utility or auxiliary non-residential premises, where there are no increased requirements for the evenness of the floor.
- Multi-layer screeds are poured in several stages. Typically, the first layer serves as a rough base, while the top creates a level surface for further flooring work. This approach is also used in cases where the total thickness of the required screed reaches too large, and it is more expedient to perform it layer by layer.
- Tied screeds have direct contact with the base. Of course, with such a pouring technology, the maximum homogeneity of materials and their high adhesion to each other should be ensured. Such coatings are characterized by good strength properties in terms of withstanding high mechanical loads. However, the condition of the surface layer will largely depend on the moisture level of the substrate. Such screeds are mainly performed on dry floor slabs on the floors of buildings.
- In the event that the base does not have sufficient waterproofing, a dividing layer sleep screed is used. A layer of waterproofing material (roofing material, polymer film, coating composition) becomes an obstacle to moisture penetration from below, and the screed itself does not have contact with the base. With this technology, the layer of the mortar to be poured cannot be less than 30 mm and, as a rule, needs reinforcement.
A similar technology is often used when installing a screed on the ground, for example, in garages, sheds, basements, on the first floors of houses without basements. They also resort to it in rooms with a high level of humidity.
- Where reinforced thermal insulation of the floor is required or there is a need for sound insulation, floating screeds are used. In this case, a concrete solution is poured over a layer of insulation of one type or another. The screed turns into completely independent design- a slab that is not connected either with the base or with the walls of the room. The minimum fill thickness in this case is at least 50 mm, and the reinforcement of the screed becomes a prerequisite.
The moisture content of such a screed is absolutely independent of the state of the base, a good insulation and effect is achieved. Disadvantages - excessively large thickness, and therefore the load on the floor. Usually, such screeds are used only on the first floors of residential or auxiliary buildings, especially if the filling is carried out on the ground.
- The addition of a cement-sand mortar of expanded polystyrene chips significantly increases the thermal insulation qualities of the coating.
Typically, such screeds require a second, reinforcing and leveling layer.
- Where screeds of large thickness or with increased thermal insulation qualities are required, expanded clay is added to the concrete solution.
Expanded clay concrete has sufficient strength, but for the flooring of some coatings, it will also be necessary to pour the face layer from a conventional solution. And here ceramic tiles it will be quite possible to lay directly on such a base.
Screeds with micro-reinforcement show good performance fiberglass... This technology makes it possible to dramatically increase the strength of the coating to mechanical stress, to tension, bending.
Such screeds usually do not crack, they are less susceptible to shrinkage during solidification, and they have less dust formation. They are great for underfloor heating systems.
It is quite natural that, if necessary, pouring a concrete screed, first of all, you will need to decide on the type of solution. In this matter, some options are possible.
According to the existing SNiP canons, the minimum strength of an ordinary concrete screed, regardless of the type of its further facing, must be at least M-150 (the coating can withstand a force of 150 kg / cm²). If used self-leveling jellied composition, here the requirements are even higher - from M-200. In accordance with these requirements, the solution must be selected.
1. The "classic" concrete mortar used for pouring a conventional floor screed is a cement-sand mixture in a ratio of 1: 3. This "recipe" is time-tested and fully justifies itself. However, there are several nuances, without which you can easily spoil the future screed:
The presence of a small amount of the gravel component of the fine fraction will not affect the strength properties of the screed. However, if a flat surface is required, it will be necessary to sift the sand through a sieve.
First, an overly liquid solution will definitely shrink when it cures. A flat surface, in accordance with the set level, is not to be expected in this case. And secondly, a violation of the cement-water balance will necessarily reduce the strength properties of the hardened concrete. The surface is loose, unbound, with increased dust formation.
There are, of course, specially the amount of water in the concrete solution, but they are usually adhered to by the technologists of enterprises for the production reinforced concrete structures and large mortar units.In home construction, they often rely on their own experience, intuition and common sense. In addition, it is very difficult to accurately calculate the amount of water and the fact that it largely depends on the moisture content of the filler. The sand can be wet, heavy - and this is also water, which will participate in the process of preparing the solution.
Ideally, the concrete solution should turn out to be dense, but plastic enough, so that when it is poured and leveled, no air voids remain in the floor. You can roughly focus on the following ratio - a liter of water per five kilograms of cement-sand dry mix.
It is important to choose the right " the golden mean"So that the solution is both dense and plastic It is very difficult to qualitatively mix the screed solution by hand, using a shovel. It is better to use a concrete mixer or a construction mixer of sufficiently high power for this. First, the dry components are mixed in the desired ratio (you can - with a little moisture), and then very carefully, in portions, add water.
An important condition for the quality of the future concrete screed is the purity of the water. It is forbidden to use industrial water containing fats, oils, oil residues, etc. Also, you can not use dirty oily containers to carry water to the place of mixing concrete.
2. The modern assortment of building materials on sale makes it possible to significantly simplify the process of pouring the screed. For these purposes, ready-made dry building mixtures can be used.
Compared to using the usual cement-sand mixture, this technology has a number of advantages:
All this will be true only if a high-quality dry mixture is purchased. Alas, there are a lot of fakes or low-grade mixtures on the building materials market in this segment. It is best to choose formulations from reputable manufacturers, be sure to check the certificate so as not to run into counterfeit products. It is also important to check the shelf life of the material - it is limited, and an expired mixture can significantly lose its qualities.
The only drawback of this approach to filling the screed is that the price for it may turn out to be slightly higher than with self-production solution. Well, convenience and quality come at a price.
Screeds and self-leveling floors
The surface for pouring the screed is prepared in different ways, based on the conditions:
- The soil is selected to a depth of 500 mm.
A pillow of sand, 100 mm thick, is poured, carefully rammed. A gravel layer is poured over it in the same way.
- Rough pouring with concrete is made with the addition of expanded clay to a height of 150 — 200 mm - for thermal insulation of the floor surface.
- After the base has solidified, it must waterproof- roofing material or dense plastic wrap to exclude the ingress of ground moisture from below. The waterproofing material must necessarily come out on the walls on a height slightly higher than the height of the planned screed. If necessary, it will be possible to fill in another layer of insulation from above, and then fill in the reinforced finishing screed.
- Firstly, old screed does not guarantee integrity, since it can peel off, crack, and these deformations will be transmitted to the newly poured layer.
- Secondly, do not forget about the maximum permissible loads on the floor slabs. So, in the serial high-rise buildings of the old building permissible load about 400 kg per square meter - static and 150 kg - dynamic. And the west of one square meter of concrete screed, 50 mm thick, approaches 100 kg. Therefore, all work related to the thickening of the screed will have to be coordinated with the design organizations, and it is far from a fact that such a permit will be obtained.
- And thirdly, the height of the canvases in apartments is usually not so significant that one could afford to greatly raise the floor level.
The old screed is dismantled with a hammer drill, but very carefully to prevent destruction or damage to the floor slab. The remains of chipped concrete are removed, and then a thorough cleaning and dust removal of the surface is carried out.
Defects are repaired with a repair mortar, epoxy putty or ordinary concrete mortar. In the case of large defects, polyurethane foam can sometimes be used.
The corners between the walls and the floor are especially carefully checked and repaired - water from the concrete solution when pouring the screed can penetrate deep into the ceiling or even leak to the neighbors below.
The soil is poured over the surface in strips and spread evenly with a roller. IN hard-to-reach places, for example, in the corners, it is better to use a brush.
Schematically - a waterproofing film and a damping tape for a screed on a separating layer After the polyethylene has been laid, the damper tape is glued in the same way as mentioned above.
In order to achieve the horizontal screed and its required height, it is necessary to create a system of beacons along which the leveling of the concrete solution will be carried out.
It is very good if the farm has or has the opportunity to take it from friends. In this case, the work will be much easier - it will be much easier to beat off the horizontal stripes on the walls and control the level of the guides.
If this is not possible, then no worse can you set beacons using water and regular building level.
The water level consists of two cylindrical transparent vessels with the same scale applied, connected by a long elastic thin hose. According to the physical law of communicating vessels, the level of liquid in them is always at the same height from the horizon. Thus, having made one mark at a certain level, it is possible to transfer it with high accuracy to other surfaces within the length of the flexible hose.
Begin marking by determining the zero level of the future screed. To do this, first of all, you need to draw a base horizontal line. This is done as follows:
The measurement point that will give the minimum height of this distance will correspond to the highest part of the base.
It is advisable to make markings for beacons and guides immediately after breaking off the zero level, guided by the following principles:
Previously, for the beacon system, various materials at hand were used as guides, for example, wooden blocks or unnecessary pipes. Today, metal profiles are mainly used for these purposes.
There are many ways to install a beacon, and it is impossible to consider everything. Let us dwell on just a few of them.
- At the far end of the room, at a distance of 250 - 300 mm from the corner between the opposite walls, a strong cord is stretched strictly at the zero level (for example, a fishing line or a thick nylon thread). It is important to pull it to the maximum so that there is no sagging in the center.
- At the intersection of the line of the extended cord with the line closest to the wall, directing to semi drilled a hole where a plastic dowel is hammered and a self-tapping screw is screwed in. Using a screwdriver, it is screwed in in such a way that the top edge of its cap exactly coincides with the zero level.
- A similar operation is repeated in the opposite, closest to the exit, side of the room.
- Two self-tapping screws, defining the line of the guide, are connected together with a tightly stretched cord, so that it passes along the top of their caps.
- On this segment, holes are marked and drilled for dowels, distributing them evenly so that an interval of 350 ÷ 400 mm is maintained between them.
- Self-tapping screws are screwed into the dowels until their caps coincide with the stretched cord. It is imperative that a check is carried out using the building level - if necessary, the required adjustments can be made.
- In the same way, a line of self-tapping screws is made on the opposite guide, and then on the intermediate ones. In this case, the check should be carried out in all directions - longitudinal, transverse and diagonal.
- After all the lines have reached the same zero level, the stretched cords are removed. A thick concrete solution is prepared. It is laid out in small slides along the line of screwed in self-tapping screws. Then a U-shaped profile is put on top and pressed into the solution. The transverse flange of the profile should rest against the head of the self-tapping screw. It is important that the profile "sits" evenly on both sides, without distortions.
Installation and fixation of metal profiles - guides - After the mortar has set and securely fixes the profiles in the installed position, you can proceed to pouring the screed.
With plaster profiles it turns out to be somewhat more complicated - it is more difficult to fix them on the heads of the screws. For these purposes, special fasteners can be used - "ears" that are put on self-tapping screws, and their petals are pressed against the side shelves of the profile.
Another subtlety is that the plaster profiles also have their own height, and this must also be taken into account when setting the self-tapping screws to the zero level.
In addition, much more solution for fixing will be required - flesh to the point that I resort to laying out even a solid shaft, into which the profile is embedded with an emphasis on the caps of the screws.
— Exposed self-tapping beacons they tied with a thin wire, thereby creating a kind of reinforcing cage. Then a slightly excessive amount of solution is laid out along the entire line, so that the resulting shaft is slightly above the zero level.
- When the mortar begins to set, a guide plane is formed. Using the rule, the upper edge of this shaft is compared and smoothed down to the caps of the screws.
- After hardening, excellent guides will be obtained, along which it is quite possible to work as a rule, and then they will enter the structure of the poured screed.
To speed up the readiness of the lighthouse system, tile glue is often used instead of the usual solution - its curing time is much shorter. But gypsum compositions are unacceptable. Firstly, they practically do not shrink, unlike cement ones. Secondly, gypsum compositions have completely different indicators of water absorption, adhesion, strength, plasticity, etc. We can say with absolute certainty that there will be bumps on the screed in the places where the lighthouses are located.
Of course, this measure is useful, especially with thick screeds. Used for this, most often, metal grid made of galvanized steel wire with cells from 50 to 100 mm - it can be purchased ready-made in stores. Only when placing it, many people make a serious mistake.
If you look at the numerous photographs on the Internet, you can see on them the mesh laid directly on the floor slab or on the waterproofing layer. There are many doubts about the usefulness of such reinforcement. Ideally, for the reinforcement belt to play its role, it should be located in the thickness of the mortar to be poured, approximately in the middle of the height of the screed.
For this, you can purchase special polymer coasters. However, it will not be t ore to make supports from wire or even raise the mesh on the lining from pieces of broken tiles or fragments of an old concrete screed. Under no circumstances should wooden linings be used.
Obviously, it is necessary to install the reinforcing grid before setting the guides. Most often, the installation of a system of beacons and fittings is carried out in parallel, and the mesh can also be fixed on those slides of cement into which metal profiles are embedded.
Oddly enough, but the process of pouring the screed itself looks, in the series of all technological operations, probably the most uncomplicated. If everyone preparatory work done correctly, this stage of complexity will not present.
If the sand has not been sifted and large fragments (pebbles or shells) remain in it, then certain difficulties may arise - these inclusions can leave furrows and you will have to suffer a lot, removing them and smoothing out irregularities in order to bring the surface to an ideal state.
The concrete solution is added as needed so that the work goes on continuously. Excess mortar at the end of filling the room is carefully removed.
After the filling is finished, you need to foresee measures excluding accidental entry of people or pets into the premises during the first 5 - 7 days. In order for the process to go effectively from maturation, the surface must be moistened daily (starting from the second day) with water, keeping it moist. In case of intense heat, it makes sense, after the initial setting, to cover it with a film, in order to avoid drying out.
If an ordinary sand-cement mortar was used, then the readiness of the screed with the operational one can be said not earlier than after 3 weeks. When using dry building mixtures, the timing may be different - they must be indicated in the attached instructions.
After the screed is ready, it is checked for evenness and surface quality. To do this, set a rule on the embedded guides and measure the resulting gap in the center. There is no escape from concrete shrinkage, and if the gap does not exceed 1 - 2 mm, then it will be within the normal range.
Often, a thin-layer composition is poured over the screed to make the surface perfectly smooth. However, this is already a topic for separate consideration.
Concrete screed is used for leveling large surfaces, most often the floor. For a rough or finish floor covering, a specific one is used for screed, since similar floors are for outbuildings, garages, storage facilities or other buildings with high level humidity is the best option a rough protective layer for floors in residential and non-residential premises from the destruction of wood by mold or fungal infections. The budget of such a design also attracts - it is simple for a screed, and the solution can be kneaded to fill the floor with your own hands, so that you get a strong and reliable concrete surface, little susceptible to mechanical stress.
The construction mixture for the formation of a monolithic floor includes three main components: lime cement, coarse river or open pit cleaned sand, and clean water... To increase the workability of the mixture, various synthetic additives can be added to the solution, for example, to increase the viscosity or plasticity, but correctly mixed solution and the sustained ratio of free-flowing and liquid materials give excellent results, and the mortar is excellently leveled and adhered to the prepared floor surface without the purchase of additives that will cost a pretty penny.
Building materials markets sell ready-made packaged dry concrete mix for floor screed. Their advantage is that it is possible to more accurately dose the proportions of concrete for the floor screed and quickly fill the working surface. There is only one drawback of such dry mixtures: they cost 1.5-2 times more than a mixture prepared on their own. Therefore, in order to save money (and in individual construction, this goal is constantly pursued), with the task set, to fill the floor on the ground at a minimum cost of building materials, the solution is prepared on its own. In this case, it is necessary to observe the following proportions of concrete for pouring the floor inside a residential or non-residential building (in weight or volume proportions):
When mixing concrete, the developer has to independently measure the volumes (weight) of bulk or liquid substances and mix them, so the result (ready-made solution) will be much cheaper than the factory packaged mixture. For M 400 and M 500, the ratio of the components listed above will correspond to the concrete grade M 150. A similar grade of concrete is used for flooring in a garage or other unheated premises with high humidity.
The solution that will be poured and operated outdoors differs in composition and proportions from the solution for internal use. A screed in an open space is constantly exposed to changes in temperature, humidity, weathering, solar radiation, therefore, its mechanical properties a priori should be better. 
| Portland cement, brand | Concrete mortar, brand | Portland cement | sand | crushed stone (weight, kg) | Portland cement | sand | crushed stone (volume, l) | Mortar volume from 10 liters of Portland cement |
| 400 | 100 | 1,0|4,0;6,0|7,0 | 10|41|61 | 78,0 |
| 500 | 1,0|5,0;8,0|8,1 | 10|53|71 | 90,0 | |
| 400 | 150 | 1,0|3,0;5,0|5,7 | 10|32|50 | 64,0 |
| 500 | 1,0|4,0;5,0|6,6 | 10|40|58 | 73,0 | |
| 400 | 200 | 1,0|2,0;8,0|4,8 | 10|25|42 | 54,0 |
| 500 | 1,0|3,0;5,0|5,6 | 10|32|49 | 62,0 | |
| 400 | 250 | 1,0|2,0;1,0|3,9 | 10|19|34 | 43,0 |
| 500 | 1,0|2,0;6,0|4,5 | 10|24|39 | 50,0 | |
| 400 | 300 | 1,0|1,0;9,0|3,7 | 10|17|32 | 41,0 |
| 500 | 1,0|2,0;4,0|4,3 | 10|22|37 | 47,0 | |
| 400 | 400 | 1,0|1,0;2,0|2,7 | 10|11|24 | 31,0 |
| 500 | 1,0|1,0;6,0|3,2 | 10|14|28 | 36,0 |
An example of a concrete structure that will constantly be exposed to all kinds of atmospheric influences on the street is a concrete blind area around the circumference of a house or garage. In this case, the grade of concrete for the garage foundation should be M 150 and be made up of the proportions of the components given below. 
The surface of the finished screed must be ironed with clean cement:
For screeds or floors on the ground that do not experience large mechanical and shock loads, marble, gravel or granite chips acting as crushed stone are allowed to be replaced with construction rubble: brick waste, furnace or blast-furnace slag, waste ceramic building blocks, etc.
Why is only M 150 recommended? It complies with the SNiP 2.03.13-88 regulations, where it is indicated that for pouring concrete screeds, a building material with a compressive strength of ≥ 15 MPa or 150 kgf / cm 2 should be used, and these indicators are only suitable for grade M 150.
The calculation of the volume of concrete solution is carried out based on the length and width of the room (meters), on the thickness of the screed (meters), and the shrinkage coefficient of the liquid solution. Example:
There is a room measuring 5 x 6 m, the layer of concrete screed is 4 cm, the shrinkage factor is 1.022 (the shrinkage factor is a reference value). After multiplying all the data (in meters), the result will be displayed in m 3: 5 x 6 x 0.04 x 1.022 = 1.2264 m 3 of the solution will need to be mixed or ordered from the manufacturer.
The shrinkage coefficient of a liquid concrete solution depends on several factors: aggregate fraction, percentage of impurities, moisture content of bulk components, etc. The real shrinkage ratio can be calculated only after practical tests and refined calculations. Therefore, for individual construction, in order to simplify the calculations, an average result of 1.022 is taken.
All the ratios of the components in the mixture and their proportions depend on the amount (volume) of cement in the mixture, therefore, you should first calculate how much Portland cement is required, after which the amount of dry bulk materials and the volume of water are calculated. For 1 m 3 of concrete for a floor screed you will need:
The result of calculating the amount of sand is as follows: 0.42 t x 3.5 = 1.470 t, or 0.37 t x 4 = 1.48 t.
To prepare DSP (cement-sand mixture), quartz sand in a ratio of 3: 1 is mixed with cement (three parts of sand and one part of cement). The volume of water in such a solution should not exceed 45-55% of the volume of dry building materials. Their proportions will result in a brand of solution M 100-M 200.
To facilitate the leveling of the surface filled with mortar, it is necessary to fill the mortar with a layer of ≤ 2-3 cm, depending on the presence and quality of plasticizers. DSP is perfect for screed small areas where you want to create a perfectly flat surface. If the pouring area is large enough (≥ 40-50 m 2), then it is recommended to mix concrete mortar with solid aggregates, since it is more durable and reliable in operation.
Despite the fact that concrete is a durable material, resistant to abrasion and other mechanical loads, it cracks and collapses after some time, and its condition does not depend on the brand. Therefore, primers and varnishes are used to protect the surface, for example, polyurethane-based varnish. This is the material with which concrete sites for industrial or industrial purposes are necessarily covered, but it is also used quite often in individual construction. The varnish, penetrating into concrete, forms a durable moisture-resistant film with protective properties. The color of the varnish is determined by adding any color.
Also, liquid substances on a polymer basis are used - with their addition, a self-leveling floor is made, sealed and moisture-proof, successfully withstanding high mechanical and shock loads. 
The technology of pouring a concrete screed is simple, and for its implementation the help of specialists is not needed - everything can be done with your own hands and with your own tools. The correct ratio of components, sequence of operations, accurate calculation and adherence to other technological conditions will make your floor beautiful and durable.
The practice of individual developers in pouring various forms of concrete screeds shows that for the formation of structures and concrete elements of an object inside a building of a small area, the most acceptable solution in terms of economy and quality is the purchase of factory dry building mixtures. For directly opposite purposes - the construction of an external concrete structure or pouring a screed of a large area - it is economically more profitable or DSP on its own and from its own building materials.
Concrete floor screed is considered the most performed type of floor surface repair. Thanks to physical properties, the screed made evens out any surface. This article will highlight the questions of what a screed is and how to make a concrete floor screed indoors.
The concrete screed is the foundation for the final coating, which can be implemented in all sorts of ways. This construction is realized from mortar and is usually the top of a laminated floor on the ground or on a slab floor. Making a concrete floor screed, several important tasks are achieved: a platform is created for laying the final base, a smooth distribution of the load on the concrete floor is achieved, and the solidity of the entire concrete floor as a whole is achieved.
Due to their use in a mixture of water, these screeds are called "wet". In addition to water, cement is included in it, as well as sand, which is mixed in proportions.
The concrete screed is a monolithic base and is realized in connection with the base or with separating, as well as insulating layers. All of the varieties presented are endowed with weak and strong points.
Installation of such a screed is carried out immediately on the base, which is prepared by applying a primer with deep penetration... This method guarantees the best grip and is able to withstand severe g-forces. For example, a similar concrete one is being implemented.
A similar device of a concrete screed assumes that a waterproofing layer was laid during the manufacture of the base, only after that the prepared mixture was poured.
Roll, coating or painting materials can act as insulation. With this type of concrete floor screed, the technology requires that the thickness be at least three centimeters. This design is endowed with excellent indicators of moisture resistance, but the strength indicators are slightly reduced.
The use of mesh for reinforcing concrete screed is still the most common type of reinforcement. To create it, a metal mesh mesh is used, laid on an insulating material on special bedside tables, so that when pouring the solution, the mesh is in the center of the screed.
The web provides the framework with improved strength and reliability. But it does not eliminate the possibility of cracking during the curing of concrete. The metal also oxidizes and over time the concrete can delaminate in the place where the network was, and this will lead to a general weakening of the product.
A new material designed to replace the reinforcing metal in floor bases - this is fiber. This material is a polymer that is added to the mortar during mixing and serves to reinforce the mortar. Also, due to the polymer, the plasticity of the entire structure is improved, which sharply reduces the likelihood of cracking.
The disadvantage of such an element is that it is necessary to very accurately observe the dosage of the fiber, if it is violated, then the concrete screed will simply collapse and it will be very difficult to repair it.
Before the concrete screed is poured, you need to take a number of measures, as well as purchase the material.
The following tool is required:
Materials to be prepared:
After purchasing all the necessary parts, you can start repairing. And the next step is to prepare the foundation.
The preparatory phase depends on what kind of flooring you have in your room. If a concrete floor screed is placed in a new house over the ceilings, then it is quite simple to clean the floor of dirt and immediately proceed with further installation.
The old floor needs to be prepared more thoroughly. It is necessary to perform an inspection, if after it no cracks, significant chips and pits were detected, then after cleaning you can move on, but if such defects are present, then they need to be repaired, and then the repaired places are polished.
But if the defects occupy an area of 30%, then you need to completely dismantle the old coating and fill in the rough screed and sand.
Often it is necessary to perform a screed along wooden floors, in this case, the production technology should be very strictly observed in order to avoid the destruction of the entire structure.
To avoid this, the following algorithm of actions is done:
After all the above actions, the foundation can be considered prepared.
To achieve an even concrete floor screed, beacons must be installed, and in order to position them correctly, you need to find a zero level.
If a laser level is used, then the procedure looks very simple:
If you are using a water level, then the procedure looks more complicated:
In this way, the basic level is obtained. Then we measure the distance from it to the base, recording the obtained values on any medium.
After all measurements, subtract the smallest value obtained from the largest.
For example:
160 - 157.5 = 2.5 cm
2.5 cm is the size of the required screed, but in order to achieve maximum strength, the structure must be at least 5 cm, so the screed must be made at least this thickness.
160 - 5 = 155 cm
Thus, we got 155 cm, the value that needs to be measured from the base level already drawn on the wall and draw a line along the walls. This is how you got the zero level, which you need to navigate so that the concrete floor screed is even.
Before starting the installation of beacons for a concrete screed, lay out the waterproofing and, if necessary, thermal insulation.
For the correct placement of the lighthouses, you need to screw the screws into the walls at the zero level and pull the fishing line between them without deflection. Thus, a reference point for leveling is created.
Then a small amount of mortar is prepared and placed in slides along the lines of installation of beacons.
Next, the acquired profile is placed on these slides and set according to the line level, while the adjustment takes place using the level. Time is waiting for the mortar to set and you can move on.
The distance between the beacons should not exceed the size of your rule. Otherwise it will be impossible to correct and polish the base.
In a container, we mix the components with the addition of water, and a mixture resembling yogurt should be obtained. The prepared mixture is laid out between the lighthouses and aligned with the rule of the lighthouses. Styling in the same room should be done in a day, and no more than three hours should pass from the beginning of the procedure to its end.
Then you need to leave the screed until it dries, after a couple of days the surface is poured with water and covered with a film. Moistening is carried out for 5 days, and then it is left to dry completely in an unventilated room. At the same time, answering the question, we can say that at least four weeks. Then, if desired, the surface is sanded.
This article deals with the question, the screed and how it is performed. Based on this article, you can make repairs yourself.
