The screed is the layer between the concrete base of the floor and its top coat. It is necessary for quality alignment gender. The durability of the result of the work depends on the screed. Screed installation is needed regardless of the type of coating used: parquet, tile, linoleum, laminate, carpet, etc.
According to the manufacturing method
- Wet. Represents cement-sand mixture. A special dry composition is also sold - it is made on cement base or using plaster. They are poured and the surface is completely leveled. If cement or sand was used for the screed, the surface is reinforced. Dry mixes do not require this procedure. The option is universal, common in construction. 10 cm or less is the optimal layer thickness.
- Dry. Also called a screed. Represents a design from sheets of the large size from 15 to 30 mm thick. In the case of strong surface differences in levels, the dryness of the screed will not allow achieving the desired degree of leveling. Then, under the floor covering, a layer of dry screed is placed on top of the wet one.
- Semi-dry. It differs from the classic, wet, manufacturing method by a significantly smaller amount of water in the mixture. The advantages of this type of screed are short period time between laying the screed and the floor, no leaks. The presence of fiber in the composition of the mixture allows you to minimize the number of shrinkage cracks.
Mechanized semi-dry floor screed provides a minimum amount of construction debris after laying. The mixture is usually kneaded outdoors and fed through a hose. For convenience, you can contact the companies involved in laying semi-dry floor screed. One of these, "EUROSTROY 21 VEK" (the company's website www.prestigehouse.ru), uses modern technology and German technology.
By number of layers
- Single layer. It is laid for 1 time to the required thickness.
- Multilayer. Consists of rough and finish surfaces. For example, to ensure rigidity at the junction of the slabs with the floor, first lay a rough concrete version, and when finishing on top, it fits absolutely smooth finishing screed. Rough screed in thickness - 20 mm or more, finishing screed - from 3 to 20 mm.
By type of connection
- Solid. It is firmly bonded to the base coat layer.
- floating. Not linked to anything. It is used when it is necessary to use a film with waterproofing properties, as well as sound or heat insulation. The optimal thickness is 35 mm or more.
Screed materials
Cement is the most common screed binder, as is gypsum. The following fillers improve the properties of the mixture: sand, polymers, mineral-based additives. To obtain the desired consistency, the composition is diluted with water.
- . The screed from it is moisture resistant, it is used for any type of floor structure. Cement mixed with sand optimal ratio- 1 part cement to 3 parts sand.
There is also sand concrete - a mixture sold in stores. Sand concrete has a drawback - fast shrinkage. Therefore, it is necessary to monitor the uniformity of the composition and the thickness of the poured layer, which must be at least 30 mm, otherwise the screed will crack.
For uniform stress distribution and protection from cracking, the screed is reinforced from the inside or a part of the propylene-based fiber is added to the solution. After laying, the screed is periodically moistened, for about 10-14 days. The screed dries for a long time and for moisture-sensitive coatings - laminate and parquet - it will remain too wet for at least 20 days.
- Gypsum. Plastic, easy-to-install screed. Does not shrink, laying it in a thin layer is allowed. Complete drying - in 1-2 days. Recommended for wooden floors. But it is not suitable for rooms with high humidity, as the gypsum will become like dough. If polymers are added to the gypsum, the screed can be used in rooms with moderate humidity.
- Concrete. In terms of composition and manufacturing technology, a concrete screed is similar to a cement screed. The main difference is that cellular concrete is added to the mixture. There are types of concrete screed: foam concrete, expanded clay concrete, perlite concrete.
- Self-levelling or self-levelling compound. Sold in ready-made, designed for various floor coverings. It happens thin-layer, from 2 to 7 mm, and thick-layer, from 5 to 30 mm. If the floor irregularities are large, first make a rough rough screed, and put a self-leveling mixture on top.
- . The composition is similar to drywall. It is a durable building board coated with waterproofing compound. Laying is done on a pre-filled layer of polystyrene. The plates are placed with a slight overlap on each other to close the joints. The main advantage of the screed is that you do not need to wait for drying. The final floor covering can be installed the next day. Often used for mounting screeds in apartments.
materials
- Concrete mixer.
- Hydraulic level.
- Rule.
- Construction bubble level.
- Master OK.
- Drill with mixing nozzle.
- Stationery knife.
- Bucket.
- Pencil, marker.
- Roulette.
- Ruler.
Stages of work
Stage 1. Definition of the horizon
The zero level is measured using a spirit level - this is how the water level is called. Marks are placed in all rooms. The optimal height is from 1.2 to 1.5 m from the floor level. The starting mark is placed anywhere. The second and all subsequent ones are marked by the water level along the horizon line, but not the floor.
All points connect and get a zero level. Throughout all installation work he will determine horizontal plane. Check the zero level accuracy several times.
Sometimes expanded clay or gravel is poured under the screed. Then they retreat a few cm from the marked point and do additional line for pouring on this level the selected cushion material under the screed.
Stage 2. Determine the height differences
This is necessary to calculate the correct level of screed and the required volume of mortar.
AT different rooms we measure the distance from the old floor to the zero level point. We write the resulting value at each measurement point. It is better to make more points so that the measurements are more accurate. Minimum value- this is the maximum level of the old floor, and the largest value shows its minimum height. The difference in values is the height difference of the old floor.
For example, max = 1.30 m, min = 1.25 m.
1,30 – 1,25 = 0,05.
That is, the height difference is 5 cm.
30 mm - the minimum thickness of the cement screed, where the plasticizer is added. Earlier, we already mentioned that otherwise cracks will go along the screed. Builders sometimes add liquid soap as a plasticizer. And on the packaging of the self-leveling mixture, the manufacturer indicates the optimal layer thickness.
With a multi-level screed - calculation of the difference in heights. Differences in height along the level of the floor at the joints of the coatings are not allowed. The screed is planned differently by levels: the thickness of the coatings is not identical. The difference in it must be compensated for by differences in the levels of the screed.
Let's say in the kitchen - ceramic tile, in the room - parquet. The layer under parquet will be thicker than for tiles and is multi-layered. We sum up the thickness of all layers, including the parquet itself, subtract the sum of the layers of the tile, including itself. We get a screed drop. It is recommended to take a spare 2 mm from the side of the tile if the parquet layer is higher.
Stage 3. Surface preparation
We clean the base coat. Usually a construction vacuum cleaner is used. In its absence, you can simply sweep well, then wash everything with a regular cleaning agent. With the help of a primer, additional dedusting can be done. Optimal use of the means "Betonokontakt" - it provides good adhesion for screed and base, makes the surface rough.
Partitions and walls require temporary waterproofing. For this purpose, you can use roofing material. The height of the roofing tape sticker is 10-15 cm from the level of the screed.
Next, we look at the base. Delaminations are not allowed, they must be cleaned. If there are large cracks, cover them with a thick mortar based on non-shrinking cement. If the floors were “ironized” during construction or smeared with “milk from cement”, then the film is removed so that there is proper adhesion to the base coat.
Stage 4. Setting up beacons
The screed is aligned on them. Rigid elements are usually used as them - metal profiles, which can be fixed in a fixed position and not be afraid that they will bend at an unnecessary moment.
The mounting method is different: you can build a hill of cement or simply screw the beacons into the floor. An important requirement is the parallelism of the guides. The distance between adjacent ones should allow putting on the ends of the rail, along which the composition will be leveled.
Beacons with the help of a rack level are aligned in length and ratio with each other. Where height differences are formed, plywood formwork is placed so that the solution cannot flow into another room or area.
Stage 5. Mixing the composition and pouring the screed
Few people do it manually, they often use a concrete mixer - this way the composition is more uniform. Do not increase the proportion of water for the homogeneity of the mixture, otherwise the screed will be fragile. For this purpose, special additives are sold that make the solution plastic and homogeneous.
The filling should resemble a thick dough without lumps, spreading, but not spreading over the surface. It is used for 1-1.5 hours and in one go. It is not allowed to leave it for several days. Also, you can not fill the room in parts for several days. An exception is a screed of different levels or different rooms.
The solution is poured between the beacons and leveled with a rail-rule, which is moved strictly along the beacons, shifting the excess mixture. To level the surface of the screed, the rule additionally makes movements to the right and left.
The process of leveling the concrete mass using the rule
Video - Floor screed
Stage 6. Post-installation care
A simple operation often overlooked by workers. It consists in watering the coating 2 times a day. If this is not done, the screed will crack. Irrigation period - 10 days.
The cement screed needs up to 28 days until it becomes strong enough. The chemical processes that take place require sufficient moisture.
Beacons are pulled out approximately 3 days after the end of the installation of the screed. The recesses are primed and filled with a new portion of the solution. After that, we moisten the coating again and cover it with a polyethylene film for 2 weeks. In some cases, this is not recommended, then moisturizing is also done often - 2 times a day.
Stage 7. Checking work
It is done in several stages.
- the matter is important, since the acquired materials should be used within the near future. If they are purchased more than expected, they will lie for a long time and may lose their properties. If you buy less of them, then you will have to again purchase the missing materials and waste your time. Incorrect calculation of material consumption and its proportions can adversely affect the quality of the most flooded in the apartment.
What affects the consumption of materials
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The main parameter that is paid attention to when calculating is patency. For example, you can not use the same one in the bedroom and the corridor. In the corridor, the permeability is much greater, so you need to use more durable cement.
Cement marking indicates the strength of the solution based on it. The number that follows the letter M indicates how durable the slab or floor screed made from such a solution is. For example, cement of the M300 brand means that 1 cm in a cube of stone from this solution can withstand a load of 300 kg (this is the upper limit). Such cement is quite suitable for apartment renovation, although M400 brand cement is considered the most popular. The maximum load that a cement stone can withstand is 700 kg per 1 cm cubed (M700).
There are other designations on the packaging of cement. The letter D, followed by numbers, means the percentage of additives in cement. For example, D2 means 2% additives, D15 - 15%. This parameter should not be correlated with the deterioration of cement quality. AT this case it's the other way around. Additional substances in most cases increase the strength characteristics of cement, making it resistant to moisture, temperature fluctuations and mechanical stress.
Other designations:
- HD - hydrophobicity of cement (resistance to moisture);
- SS - sulfate resistance (the material easily tolerates freezing and thawing);
- PL - plasticizing additives (gives additional plasticity);
- VRC is an expanding cement that does not allow water to pass through.
Conventional screed: the necessary calculations
Advanced builders and craftsmen do not need any calculators and formulas. They almost intuitively determine how much of what is needed. In fact, their hand is already so full that they easily carry out all the calculations in their minds.
It's a little more difficult for a beginner. If you really can’t cope with the calculations at all, a calculator will help. Many construction sites have special calculators with which you can easily calculate the cost and right amount materials. On average, one bag of cement (M400) weighing 50 kg goes to a floor screed 1m2 10 cm thick.
A more accurate calculation for a semi-dry screed can be done using the following formula: multiply the area by the height of the screed. If the room has an area of 50 m 2, and the screed should have a height of about 5 cm (0.05 m). This means that 50 m 2 must be multiplied by 0.05 m. The result will be - 2.5 m 3 (solution volume). But in further calculations, it must be taken into account that the volume of materials is 25-30% more than the volume of the solution from these materials. To help you need to take these numbers:
- 2.5 m 3 divided into 5 parts. As a result, we obtain the volume of one part - 0.5 m 3.
- 0.5 m 3 is multiplied by 4 parts of sand. The result is 2 m 3 (the required volume of sand).
- 1625 kg (the weight of a cube of sand) is multiplied by 2 m 3. As a result, 3250 kg of sand comes out.
- 1300 kg (all cubes of cement) are multiplied by 0.5 m 3. The result is 650 kg of cement.
To calculate the amount of sand and cement that are needed for shrinkage (in addition to the previous quantities), use the following formulas:
- 3250 times 0.25. The result is 812.5 kg (sand);
- 650 times 0.25. The result is 162.5 kg (cement).
The final number is obtained by summing up the results obtained:
- add 812.5 to 3250. The result is 4062.5 kg (sand);
- add 162.5 to 650. The result is 812.5 kg (cement).
As a result, a little more than 2 tons of sand and 812.5 kg of cement (about 16 bags of cement) will be required. The last digit is obtained by dividing total weight cement for the weight of one bag (50 kg). If cement is sold in bags of 25 kg, then the total weight is divided by this figure (32 bags come out).
Which floor screed is best for concrete floor slabs and wood floors? In the process of construction and repair work, it is very often necessary to replace old wooden creaky floors with new, reliable and durable ones. It is not so easy to do this without a screed device. There are several different types of device for this leveling subfloor.
What are the types of screeds
Many have heard of such a concept as a floor screed, but not everyone knows its purpose. In the construction literature, it is defined as a leveling cement-sand layer laid on the floors, on which it is laid top coat. Today, not only cement and sand are used in the construction of screeds. There are other more modern materials. Which floor screed is better - everyone can understand for themselves only by studying the features of all its types. In addition to leveling the surface for laying the finish coat, the screed has a number of other functions:Rules for the installation of a wet floor screed
With a large-scale repair of an apartment, it is rarely possible to do without the installation or reconstruction of subfloors. In most cases, builders recommend pouring a cement-sand or concrete screed, which allows you to create an even base for flooring without excessive costs and in a relatively short time. What else should be kept in mind at this stage? What materials and technologies to use and how to avoid mistakes? In the article you will find answers to these questions.
Building codes (SNiP 3.03.01-87 "Bearing and enclosing structures") allow a level difference at the joints of floor slabs of up to 12 mm and a deviation from the horizontal within a span of 4 m long - up to 10 mm. In practice, these values are often exceeded, and in the process of shrinkage of the house, even more noticeable ledges and slopes are formed. The most versatile and in a reliable way leveling the floor in the apartment is pouring wet screed, the technology of which is constantly being improved.
The main features of the wet floor screed
Please note that demolition and construction work that changes the structure of the subfloor requires a permit. And for this it is necessary to prepare a project that provides for the protection of the downstream premises from leaks and impact noise.Waterproofing
In the process of pouring the liquid solution, moisture can seep into the floor cavities and into the apartment on the lower floor through the joints of the slabs. In addition, dry slabs are able to quickly “pull out” water from the bottom layer of the solution - the concrete will dry out and will not gain the necessary strength. To avoid these troubles, before starting concrete work, you need to create a waterproof “trough”, using coating or roll materials for this purpose (we will return to them later). The created water seal will be useful in the future - in case of small leaks, it will prevent the neighbors from below from flooding. Impact noise protection. The soundproofing ability of the floor is characterized by the reduced impact noise index (Lnw), measured by a special method (SNiP 23-03-2003 "Protection from noise"). At the same time, in residential buildings, the maximum permissible value of Lnw is 58 dB. However, tests show that this parameter is usually higher (the worst results, up to 65 dB, were obtained when examining panel buildings buildings in the 70s and 80s. last century). An acceptable level of sound insulation helps to achieve damping substrates located under the floor screed and / or floor covering. At the same time, some materials with a thickness of only 3-5 mm can reduce Lnw by 20-25 dB and provide peace to your neighbors, and in addition, protect yourself from structure-based noise that occurs in high-rise buildings. Universal solution. Until recently, for hydro and sound insulation, different materials- let's say, soft fiberboard was first laid, and then the surface was covered with plastic wrap. Today, there are universal substrates on sale - both waterproof and vibration-damping (that is, damping shock vibrations). Some of them are produced in the form of plates glued to the base, such as products made of extruded polystyrene foam "Antistuk" ("Ruspanel"). Others, say Technoelast Acoustic (TechnoNIKOL) or Shumanet-100 ( Acoustic materials and technology"), are mats made of mineral fiber with a bitumen or rubber-bitumen coating. In addition, the substrates are made from compressed cork, polyethylene foam or foam rubber.
Before styling insulating materials plate joints are smoothed cement putty, and in wet areas it is recommended to apply a layer of cement-polymer or rubber-bitumen mastic to the concrete afterwards (as an additional insurance against leaks). Hydro and noise insulating mats (plates) must be brought to the walls to a height equal to the calculated thickness of the floor "pie". Thus, transmission is excluded structural noise from the screed to the walls and vice versa. joints roll materials glued with special adhesive tape or mastic.
From start to finish
When installing the screed, it is important to achieve a high strength of the base layer and ideally flat surface(limit level difference - 4 mm per 2 m). In addition, it is impossible to create an excessive additional load on the floor: deformation load-bearing structures as a result of alteration of floors - not such a rarity. base layer. When determining the zero level, they proceed from the minimum allowable (in terms of strength) local thickness of the screed - 25-30 mm. A laser level and beacons help to "beat off zero", for example, from steel guide profiles for drywall. Beacons are securely fixed so that they do not move during concrete work. If the overlap is even and the average thickness of the screed does not exceed 40 mm, the base layer can in most cases be made of cement-sand mortar brand not lower than M200. It is desirable to add plasticizing, sealing and water-repellent additives to it, such as Ceresit CC 92 (Henkel-Bautechnik), Tiprom C (SAZI), ArmMix Superplast (Alliance-ST). With an estimated screed thickness of more than 40 mm, lightweight concretes are used - expanded clay concrete, foam concrete, polystyrene concrete, etc. The advantage of expanded clay concrete is low cost, availability of components and the possibility of preparing a mortar on site (using a compact concrete mixer or manually). The density of the material is 800-1000 kg / m3, that is, it is 1.5-1.7 times lighter than sand concrete. Approximately the same characteristics are possessed by monoliths from ready-made mixtures with special fillers (for example, foam glass), but their cost is 2-2.5 times higher. The density of foam concrete is even less (500-600 kg/m3). However, it is difficult to prepare it yourself: specific precisely dosed components are required, which will have to be mixed for a long time. Some companies have equipment that allows you to supply the finished solution to a height of 40-50 m, but the cost of the subfloor at the same time increases at least twice, in addition, companies using concrete pumps take only large amounts of work (from 100 m2). An alternative to commodity foam concrete is polystyrene concrete from ready-made mixtures, for example, Glims-LS (Glims). By the way, this material is more plastic and shrinks less. When using light mixtures, even grades 400 and 500, the minimum thickness of the base layer should be 45-50 mm, otherwise there is a high risk of cracking.Finish alignment
The base layer cannot be made perfectly even: the filler fraction is too large, besides, the mortar shrinks unevenly (depending on the layer thickness). To "bring" the surface, use special mixtures. They are applied in a thin layer (3-5 mm) when the base gains about 70% strength, that is, after 1-2 weeks; some polymer compositions can only be laid on completely dry concrete treated with a contact primer.
Floor levelers are divided into putty and self-leveling. First (wide range of cement, acrylic and epoxy finishing putties) have a pasty consistency; they are applied with a long spatula. From the latter, for example, Tribon (KNAUF) or "Horizon" ("Eunice"), a liquid solution is prepared that is capable of spreading itself over the surface. Self-leveling floors are optimal for leveling large areas, but working with them requires skill and responsibility: you must follow the instructions for preparing the solution exactly and distribute it very quickly over the surface. Another nuance is the presence on the market of fakes and expired mixtures (their shelf life does not exceed six months). A mortar prepared from low-quality raw materials does not have the necessary compressive strength and may peel off from the base screed.
Typical mistakes when installing a wet floor screed
1. Pouring a thick (more than 40 mm) screed made of heavy concrete, chipping the floor slab when laying pipelines, installing beacons. 2. Pouring mortar directly onto the floor slab (without a waterproofing layer): leakage to the floor below is inevitable, there is a high risk of damage to hidden electrical wiring. 3. Fast and uneven drying of concrete, causing deformation of the screed, reducing its strength and delamination. 4. Refusal of reinforcement or incorrect reinforcement and as a result - cracking of the screed (especially likely when using lightweight concrete and a small layer thickness). 5. Ignoring the thickness of the floor coverings is fraught with the appearance of differences in the level of the finished floor.Semi-dry floor screed technology
The expression "semi-dry screed" quite eloquently explains the essence: here, significantly less water. When such a solution is prepared, exactly as much water is introduced into it as is required for cement hydration, that is, for the molecules to form strong crystalline bonds.Advantages of a semi-dry screed
A mixture devoid of excess moisture, which turns into stone as a result of the hardening process, becomes not only easier, but also less laborious to use. It also has other advantages: 1. Higher density, which allows you to increase the strength of a building object or structural element. Since, during the preparation of the mixture, excess water does not get into it, which is excessive for cement hydration, there will be no subsequent long process of its evaporation, and at the same time the appearance of pores, cavities and voids. And the fewer pores in the monolith, the stronger it will be. 2. The absence of pores in the hardening mass also leads to the absence of shrinkage. 3. The absence of the process of evaporation of excess moisture greatly accelerates the maturation of the screed. 4. When a semi-dry screed is used, the technology of its application is much cleaner than the traditional one - without dampness and sticky dirt. 5. In the process of working with a semi-dry screed, the humidity in the room does not increase, which allows you to simultaneously engage in finishing work here.
You can walk on a semi-dry screed already 12 hours after its formation, and in order to do the finishing in this room (except for laying the finish), it will be enough to wait just one day. Also, much earlier it will be possible to proceed with the final finishing of the floor surface than with traditional technologies.
Cons of a semi-dry screed
Of course, a semi-dry floor screed also has disadvantages: 1. The density of the screed brings not only pluses, but also minuses: the material does not spread well, which is why it is difficult to form clear corners at the junction of walls with the floor or among themselves, instead of them rather smooth ones are obtained transitions. 2. The difficulty of manual work with a semi-dry screed when it comes to sufficiently large areas (more than 75 sq. M). 3. The impossibility of applying a layer thinner than 3 cm, optimal value for him is 4-5 cm. 4. When a semi-dry screed is used, they try to correct its shortcomings with various tricks. For example, excessive density is compensated by the addition of plasticizers. A clear dividing line in the corners is obtained in the most primitive way - immediately after laying the leveling mass, it is subjected to ramming.Semi-dry screed reinforcement
To prevent cracks in the semi-dry screed, fiber is added to it, which is increasingly replacing the conventional reinforcing mesh from the screed preparation technology. There are several reasons for this:Pouring a semi-dry screed
1. Cover the subfloor with waterproofing, roofing material or polyethylene in such a way that the waterproofing strips form a kind of pallet with sides extending 15 cm onto the walls, and the strips themselves are overlapped and then fixed with adhesive tape. 2. Vertically fasten polypropylene electrical tape along the perimeter of the walls, which must first be cut into strips of suitable sizes. It is recommended to use isolon 10 cm wide and 8-10 mm thick. 3. On the walls, you need to mark in advance with a simple or laser level required tie height. After that, on top of the waterproofing, in accordance with the given level, it is necessary to build rail beacons from the mortar beds, on the crests of which the guide profiles must be supported. Linear beacons, on the other hand, must be positioned so that the rule rests on two adjacent rails, while 20-30 cm remain between the guide and the wall. The mixture must be immediately compacted (it is advisable to involve assistants for this). 5. Put a semi-dry mixture on the compacted surface, but already above the level of the beacons, after which the screed is simultaneously compacted and leveled. 6. Sand the formed screed immediately.
7. In rooms whose area exceeds 12-15 m2, after a day you need to cut along the walls expansion joints, the depth of which is one third of the leveling layer, and the width is 3 mm. 8. After that, semi-dry cement strainer should be covered with overlapping sheets of polyethylene and left for some time (from 1 day to 1 week if conditions for curing are normal). AT hot weather the screed will have to be moistened with water for several days so that the hardening proceeds normally, without the formation of cracks and deformations.
How long does a semi-dry screed dry?
Since a semi-dry screed does not shrink the surface, it can be grouted immediately after leveling with the rule. After that, you need to wait until the screed is completely dry. The advantage of the new technique is that after 12 hours it will be possible to walk on the freshly prepared floor, and after the same amount of time in the room, you can safely continue further finishing work. Also, much earlier it will be possible to do the laying of the finishing floor covering than was permissible when old technology fills. However, there are some nuances here as well. Although the semi-dry floor screed technology is considered a modernization, it is also imperfect, so not all work after it can be started at the same time. It all depends on the properties that certain floor coverings possess:What are the advantages of dry floor screed
If we compare the technology of dry screed with the traditional "wet" pouring of cement-sand mortar, or ready-made building dry mixes for floor screed, then a number of advantages immediately emerge: 1. First of all - the timing of the work. It is possible to lay a dry screed in a room, if you have the skills, in 1-2 days. The repair process is practically not slowed down. 2. Absence wet technology- Dirt is not spread through the living quarters. 3. No cement dust, which can be dangerous for people with a tendency to allergies or asthma. 4. The complexity of the process, including loading and unloading operations, lifting materials to the floor, is several times less. 5. The work will not require any special equipment (such as concrete mixers, construction mixers, specialized containers, etc.) 6. In a dry screed, it will not be difficult to hide intra-apartment communications. 7. Dry screed is an excellent additional thermal insulator and soundproofing of the floor in the apartment. 8. The most important advantage is the relative lightness of the resulting screed. It can be laid even on the old wooden base, subject to its strength. It is clear that this is unacceptable with a concrete screed.
9. Interfloor ceilings experience a much lower load, and in some cases this is a determining factor for choice, especially if repairs are carried out in houses of old construction. 10. Dry screed allows you to achieve the required evenness of the floor covering with sufficient strength characteristics of the surface. So, with properly carried out work, such a coating is resistant to a distributed load of up to 1 ton per square meter. meter, or point - up to 360 kg. This technology does not limit homeowners in choosing the floor finish, and its laying can begin immediately after the completion of work with the screed.
What is dry screed
In fact, this is a system of materials laid out in a certain sequence on the floor surface to be leveled: 1. Waterproofing membrane (film) laid on the floor slab (old surface). 2. Edge damper tape, which creates the necessary compensation gap along the walls of the room. 3. Leveling coating. The most commonly used backfill materials are fine-fraction expanded clay, slag, slag pumice, perlite expanded sand. If the floor level does not require leveling, they also resort to laying thermal insulation boards - from extruded polystyrene foam (EPP) or mineral wool high density. This layer levels the floor and creates the required thermal and sound insulation. The top layer is sheet material, on which the floor finish will subsequently be laid. It will take on the main loads and evenly distribute them to the filling bottom layer. OSB, moisture-resistant plywood, chipboard, asbestos-cement boards are used as sheet material. Recently, however, GVLV is most often used - moisture-resistant gypsum-fiber ready-made elements for laying the "rough" floor surface.
The total thickness of such a "pie" is from 35-40 mm, of which 20 falls on the upper sheet layer. At lower values, the floor will not properly meet the requirements of strength and stability. The maximum thickness, in fact, is not limited, but subject to certain nuances of technology.
How to make a dry floor screed
The process of laying a dry screed can be divided into several stages.Foundation preparation
The main requirements for the base are the absence of significant surface defects, stability. Often you have to resort to dismantling the old coating, especially if you want to lower the overall starting surface level. The plane of the base should not have protrusions - they can damage the waterproofing film. It is equally important to get rid of failures, cracks, holes. They, of course, can be leveled with a dry backfill, but in these areas, voids, air "pockets" will inevitably form under the film. Over time, the backfill layer in these places can sag, sometimes even breaking through the membrane, and areas of instability will appear on the floor, which, at best, will manifest themselves as an unpleasant creak. Irregularities can be repaired with any quick-hardening compound with rough leveling to the general level of the base. Then you need to thoroughly clean the surface of small pebbles and dust, best of all - with a vacuum cleaner. If it is planned to lay a dry screed on a wooden floor, it is worth conducting a thorough revision and, if necessary, replacing it problem areas or strengthen them using self-tapping screws. There should be no large gaps on the floor.waterproofing layer
It is believed that the waterproofing layer is not mandatory with this technology. However, when placed on concrete base, it never hurts. As a separating membrane, a conventional polyethylene film not less than 200 microns thick. They cover it either with a single piece, or with stripes with an overlap of 15-20 cm and gluing the joints with adhesive tape. Be sure to make an allowance for the walls of the room - 10-15 cm.
After that, it is necessary to immediately glue the damper tape along the perimeter of the room, so that in its width it protrudes somewhat above the surface of the planned coating. If the screed is poured onto a wooden base, it will be covered with tar-impregnated construction paper. The flooring technique is the same - overlapping and, if necessary, gluing the joints.
The device of the main backfill layer
First of all, you need to set the required level of the backfill layer. It is carried out using a building water or laser level and is fixed by a system of beacons. The installation of beacons, in principle, does not differ from the usual practice. It is most convenient to use galvanized profiles for plasterboard as guides. There is one significant caveat - if with a conventional screed, beacons are most often left in the thickness of the coating, then when leveling the floor with a dry screed, they are subject to mandatory withdrawal. This is explained by the fact that bulk material, no matter how you tamp it down, it cannot but give at least a minimal shrinkage. In this case, the upper covering layer will not fit snugly against the filling layer, resting against the beacons, which will lead to deformation, squeaks, etc. Thus, the lighthouses, as the main layer is backfilled, move from place to place. Backfill material in a slightly excess amount is laid out on the desired area. The leveling of the surface is done by the rule. With a large layer thickness, it may be advisable to carry out additional tamping, for example, with a wide wooden or PPS plaster trowel. Sometimes, with large areas, it makes sense, after backfilling a certain area, to immediately cover it with sheet material. They act differently - first they completely level the backfilled layer throughout the room, and then lay the top coating. In this case, it is possible, for the convenience of movement without violating the integrity and evenness of the backfilled layer, to lay temporary footbridges.Laying the top layer
It will be most convenient to use ready-made GVL floor elements specially designed for this purpose. They already have a two-layer structure with a lock, which greatly facilitates the installation of the coating. They are laid, starting from the corner of the room. As for the direction of laying, there is no unity - some prefer to move from the door deep into the room, others insist on the expediency of the opposite direction. When laying out the second row, a 250 mm indent is made at the joints. Docked sheets are connected with glue (PVA is quite suitable) and fixed with self-tapping screws with the caps deepening into the thickness of the material. Installation of a coating from other sheet materials is carried out similarly, but sequentially in two layers. Ligation is also done along the longitudinal and transverse seams. Fixation - glue and screws.
It is not recommended to make a seam between sheets in doorway- it is better to retreat in both directions at least 200-300 mm. After the complete laying of the top layer, the waterproofing protruding along the perimeter of the room is trimmed and damper tape. In fact, the floor is already ready for laying the finish coat. All in all, it takes the least amount of time to complete the job. An experienced team can cope with a similar task in one room in just a day.
A floor screed in an apartment is necessary when it is required to make the coating even, without drops and slopes. This approach will increase the strength of the surface. The possibility of finishing doorways, installing windows depends on the quality of work - all components must be on the same level.
Why else do you need a floor screed? With help similar events it is easy to insulate the room, reduce the impact of noise, provide waterproofing. Correct design let disguise engineering Communication: cable, pipes or other elements.
The difference in the height of the interior space may turn out to be insignificant - up to 1 cm, or it can be a very unpleasant surprise: some newcomers on the forums say that the difference in values over the entire area of \u200b\u200bthe premises reaches 10 cm.
In order for the floor coverings to please for a long time, and the furniture to be installed without distortions, it is necessary to form the most even bottom. Experts say: before starting finishing events it is reasonable to watch videos, get profile information from articles or chat on the Web with like-minded people who will tell you how to properly make a floor screed in different rooms of the apartment, which one is better under specific circumstances, and what the final choice depends on.
For large-scale spaces, it is reasonable to invite professionals or, using the advice of experienced ones, do the finishing yourself. The screed for the floor of the apartment is performed according to the general algorithm. There may be nuances when choosing different materials.
Masters offer to combine several techniques, which is justified with a significant curvature of the base. Any composition needs to be completely dried before laying the final coating.
Types of floor screed
Today, the following types of floor screeds are relevant:
- Wet. The solution is mixed with in large numbers water, takes a long time to dry. Reinforcement is often used, so this type of screed is suitable if an increased load is expected.
- Semi-dry. This variety remains the most popular. A small amount of moisture and the presence of a hardener speed up the drying process. The composition is quite suitable for a moderate load of the residential sector.
- Dry. Universal way for an apartment. Initial leveling is carried out by different types of bulk eco-friendly mixtures. The floor is formed from drywall, plywood.
- Self-leveling or self-leveling, which is distributed evenly over the surface.
Each of the modifications has pros and cons: the wet method remains the most durable, but laborious. Semi-dry look - easier to perform, will allow you to complete finishing activities faster.
Plywood or GVL are quickly mounted, but are suitable for ordinary housing, and with great traffic they will be unstable. Self-levelling compounds are ideal for rooms with minor surface imperfections.
Any of the named varieties for the floor in the apartment is suitable for installation with different initial data. For example, for a common corridor, if the family is numerous, you can use a semi-dry option, and in the bedroom you can limit yourself to a practical bulk one.
Cement strainer
Cement-based mixtures may have various properties, since the proportions of the components can be varied. Concrete screed The floor in the apartment can be cooked by yourself. Experts recommend adhering to the following compound formulation:
- Project mortar 100, and cement "300"? Then you need a part of cement and three - sand.
- "Dvuhsotka" - respectively 2 to 1.
Calculating the total is easy. With 5 cm in height and 20 m 2 of the area of \u200b\u200bthe room, you will need: 0.5 * 20 \u003d 10 m 3 of the finished concrete mix. A plasticizer (you can take liquid soap) will add viscosity to the filling.
Nuance: in the process of kneading, the volume decreases. From 1 m 3 of dry raw materials, no more than 0.75 m 3 of solution will be obtained.
For apartment repairs, only fine aggregate is used: sifted sand. A reasonable step is to make a floor screed with expanded clay. Concrete is mixed with light practical material. This method is rational when it is worth raising the surface to a considerable height. This finish is useful when it is necessary to reduce the weight of traditional cement or concrete.
Dry floor screed
A semi-dry floor screed in an apartment is used as a simple main surface or for arranging warm communications. The use of such a solution allows you to start further work 2-4 days after installation. The addition of fiber will enhance insulating properties coating will make it more stable.
Doubt what kind of screed is needed, dry or wet? If an average load is expected and the repair time is short, then the option using an almost dry solution will be more attractive.
A dry screed can be done in one day and the top coat is easy to install with no time loss. The base slab is covered with a dry mixture, aligned with the beacons. Then the profile guides are set, on which the cut sheets of drywall (plywood) are attached. The gap between the wall and the floor is filled with mounting foam.
Stages of work
The process of leveling the floor and forming the screed is divided into standard steps. They differ depending on the method used, but the schematic outline remains the same:
- First, the initial preparation of the rough surface is done.
- Thermal, hydro, sound insulation is carried out.
- It is produced, if planned, reinforcement or additional equipment is installed.
- Filling in progress.
The source material for the floor screed in the apartment determines the necessary set of tools. Irreplaceable helpers are traditional lighthouses. To level the dry backfill, you will need rails, a profile, fasteners, a screwdriver, a jigsaw for cutting.
A self-levelling compound will require a roller to disperse air bubbles. Wet and semi-dry options are the most voluminous, here they select: a level, a trowel, a spatula, a drill, a mixer for kneading, containers of different sizes, a rule.
Foundation preparation
If repairs are made in the secondary housing market, then it is necessary to remove the old floor screed. Otherwise, the new base may reveal hidden defects in the existing coating.
Then you should carefully remove dust, dirt, fine particles, repair cracks between the ceilings, recesses on the plane. After the solution dries, the plate is polished with a brush or machine, all excess is removed. The surface needs to be thoroughly vacuumed.
fill
First make a solution. Cement, sand, water are mixed proportionally (for example, 3:1:0.5). Dry sand and cement are stirred, carefully rubbing the particles. Then the liquid is gradually poured in. For greater plasticity, you can add liquid soap or dishwashing detergent. If a ready-made version was purchased, then it is diluted according to the instructions.
Masters know how to properly pour the composition throughout the room and recommend that the resulting mixture be evenly distributed over the floor. It is better to use beacons as guides. If somewhere the solution turned out to be small and depressions formed, then the material is thrown up and leveled again.
Make sure that there are no air pockets left, and the composition fills the entire space.
Criterion: if the solution lies tightly and qualitatively on the slab, then “cement milk” will appear on the surface.
After partial hardening, the canvas can be further sanded with a grater. With the semi-dry method, the surface is treated when setting becomes apparent.
Do-it-yourself screed
Professionals give advice to craftsmen who decide to make a floor screed with their own hands:
- When using the wet and semi-dry method, the usual liquid household solutions (soap, degreaser) can be replaced with PVA glue.
- Mounting wet ways must be done in one session. The batch storage time is up to 2 hours.
- The calculation of the drying period depends on the thickness of the layer: 1 week is suggested for 1 cm of height.
- Semi-dry application dries up to 2 weeks (4-5 days is enough for a thin layer), but after 10-12 hours after laying it can be walked on in flat shoes.
When installing a dry floor in an apartment with your own hands, it should be remembered that the design is less durable, but is able to withstand household loads. As a primary backfill, it is reasonable to purchase expanded clay, perlite, environmentally friendly compositions with a fine fraction. Practical top coat gypsum fiber sheets under which layers of insulation can be laid. It is easy to perform such manipulations yourself in 2-3 days.
A semi-dry floor screed is kneaded hard-boiled with your own hands: a lump clenched in a fist should not crack or crumble. It is not necessary to get the laid beacons from the thickness. With this method, you can save on a self-leveling finish layer: the floor without it will come out smooth and flawless. This type among professionals is considered the most popular when decorating apartments, since it reduces the hardening time, remains practical, stable.
The floor screed is the part of the base that is located between the ceiling and the finishing coating. Without it, it is impossible to make the floors perfectly even - such that even the most demanding installation conditions can be laid on them without fear. finishing material. You can’t do without it when building a house and even during the overhaul, but how to make a floor screed is a very difficult question for many. Let's try to figure out how to create it with your own hands.
The screed is not only a structural element of the floor, responsible for its leveling. It performs other equally important functions - for example, it takes over and redistributes all the loads experienced by the floor covering. But still, the most important function of the screed is precisely the alignment of the base. It is necessary in order to lay the floor covering without problems and correctly, some types of which are quite demanding on the evenness of the subfloor. For example, ceramic tiles, parquet and other materials will quickly become unusable if they are operated lying on uneven floor. They will begin to break and collapse, and when moving along the coating, it will emit an unpleasant creak.
Another function that the screed performs is increase in heat, sound and waterproofing properties sexes. Also, due to it, it is easy to raise the level of the base to the required level if necessary.
What is the screed?
The floor screed can be divided according to several criteria into different kinds. For example, depending on the manufacturing method, it can be dry, wet, combined.
Table. The main types of screeds.
| View | Description and characteristics |
|---|---|
| This option is made without the use of heavy mortars. The technology is used to level floors with very large height differences (up to 11 cm), as well as in rooms where floors cannot experience significant load. In this case, a dry screed can be laid along the logs and be made of plywood or chipboard, or it can be made of sheets of gypsum fiber, which is laid on expanded clay bedding. The thickness of the screed can be quite large. Dry screed is easy to perform, does not require drying after production, is very light, does not exert a load on the floors and foundation of the building. |
| This screed can also be called concrete or cement. The most familiar and most commonly used way of leveling and raising the floor. As a rule, it is used for the initial stage of leveling floors or subfloors. It is made on the basis of cement with the addition of fillers, it is laid in a layer of 3 cm or more. Difficult to work with, takes a long time to dry, but very strong and durable. Unfortunately, it exerts significant non-overlapping pressure due to its considerable weight, and therefore cannot be applied to all types of buildings. For 1 sq.m. accounts for at least 100-120 kg mortar- the mass is quite impressive. |
| This type of screed combines the main advantages and, in some way, the technology of wet and self-leveling screeds. |
| This method is good because there is no need to use beacons and somehow monitor the evenness of the finished base. The fact is that special mixtures are used for manufacturing, which tend to self-level on the surface of the subfloor. Such compounds are quite expensive, and they can be filled with floors with irregularities up to 2 cm. Often, due to this method, you can additionally level the usual cement screed. |
Also screeds are divided into different types depending on the number of layers. Thus, they are single layer(poured immediately at a time to the required thickness) and multilayer. The latter have the so-called rough and finish surfaces. As a rule, the rough base has a thickness of 2 cm or more, and the finishing one - 3-20 mm.
According to the type of connection with overlappings, screeds can be divided into solid and floating. The first has a reliable connection with the draft base, the second has no hitch with anything. For installation, hydro- and heat-insulating materials are used.
What can be used to create a screed?
Depending on the type of screed, they can be made of various materials. So, to create a wet screed, cement, water and sand are used. Cement in this case acts as a binding material, and sand becomes a filler. To improve the quality of building mixtures, they can be added various components improving strength and reducing drying time.
On a note! To prepare such a mixture, it is necessary to mix 1 part of cement with 3 parts of sand. The required amount of water is added to them. This is a fairly economical option.
To create a wet screed, ready-made sand concrete sold in stores can also be used. Its main disadvantage is the high shrinkage rate. Because of this, the thickness of the screed layer cannot be less than 3 cm, otherwise it will quickly become covered with cracks.
Advice! To reduce the risk of cracking of the screed, fiber fibers are added to the raw composition, or layers of reinforcing mesh are laid on the rough base.
For wooden floors gypsum-based mixtures are used. This material can be laid in a thin layer, as it practically does not shrink. Drying time is also attractive - only 1-2 days. The only exception in terms of the use of such formulations is high humidity in the premises.
Self-levelling or usually used for the final leveling of conventional wet screed. The reason is the rather high cost of the material. Such a composition is used for leveling floors with an unevenness of 2-7 mm.
Required for manufacturing sheet materials type of drywall, as well as expanded clay of medium and fine fraction for backfilling the base. The joints of individual sheets of material are treated with adhesives.
How to make a floor screed
Work on the installation of floor screed invariably raises questions from beginners. Below are instructions for creating a dry, wet and semi-dry screed. However, no matter which option is chosen by the masters, in any case, before starting work, it is important to prepare a rough foundation.
Features of the preparation of the base
To begin with, if the house was not built from scratch, you will need to get rid of old finish gender. Moreover, you will have to remove the old screed up to the overlap. It is especially important to repair any flaws on the base. It can be cracks, chips, any gaps. All this must be sealed with sealant or cement composition after pre-priming to avoid too big expense mixtures (relative to wet screed) and increase the adhesion of the compositions to the base.
Preparing the base for the screed - photo
On a note! Sometimes a new screed is poured directly on top of the old one, but this is only acceptable if the previous version of the base is strong enough. However, only an experienced specialist will be able to assess the condition of the old screed. Sometimes it is even enough to use just self-leveling compounds to make the old base perfectly even.
You can clean the floor from the old screed using a jackhammer. Further, the base is cleared of construction waste, which is placed in strong bags and taken to a landfill.
Small protrusions on the old screed can be removed by arming grinder. After preparation, it is important to prime the base in order to increase adhesion.
Making a wet screed
Step 1. Everything is prepared first necessary tools and materials. it building level, slats that will act as beacons, self-tapping screws and dowels, building mixtures, sand and cement, usually perforator.
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