If the floors in the house need not only leveling, but also insulation, the ideal way to do this would be a floor screed with expanded clay - the technology for performing this work has long been worked out and even has several options. Each of them has its own nuances that must be taken into account in order to obtain a high-quality surface. And the choice of method depends on the state of the base and some other factors, which will be discussed later.
Advantages of expanded clay screed
If we compare expanded clay screed with traditional concrete, then we can find only one serious drawback: the impossibility of laying a thin layer, which is important with low ceilings. The disadvantages could be attributed to lower strength than concrete, but it is quite sufficient for residential premises.
But the advantages of a screed with expanded clay has many. These include:
- floor insulation on any basis - soil, reinforced concrete slab, wooden flooring. And, as a result, increased comfort and reduced costs for heating the house;
- providing sound insulation between floors;
- the ability to level any level differences;
- reducing the cost of leveling the base;
- the possibility of laying on insufficiently strong and reliable foundations, since expanded clay screed is much lighter than cement, and therefore does not create a large load;
- the possibility of laying communications under the floor in a thick layer of screed.
All this together makes expanded clay rough coating much more preferable than concrete. There is only one limitation for its use - this is a high probability of moisture getting into the thickness of a dry screed. That is why it is not recommended to install a water-heated floor in it. Expanded clay gets along well with electric and infrared.
For reference! Expanded clay itself is not afraid of water, it does not collapse from its impact. But moisture stagnation is dangerous by the appearance of dampness in the house and the formation of mold.
Varieties of expanded clay
Floor screed with expanded clay is performed different ways, which can be divided into dry, wet (traditional) and combined. For each of them, the material is selected individually. About the methods a little lower, but for now let's figure out what expanded clay is and what properties and characteristics it has.
Expanded clay granules: dense outside and porous inside Source ec-nn.ru
The basis of the material is clay with special additives. The raw material is subjected to high-temperature firing, as a result of which it swells with the formation of many small closed voids inside and a dense crust on the surface. Such a porous structure allows the use of expanded clay as a heater with unique properties. With a sufficiently high density and strength, it is lightweight and resistant to moisture.
Depending on the method of production, the shape and size of individual particles, the material is divided into 3 types:
- expanded clay crushed stone, the main difference of which is irregular shape particles with a size of 0-40 mm obtained by grinding large stones;
- expanded clay sand, consisting of rounded granules less than 5 mm in diameter;
- expanded clay gravel is also a mixture of oval or round granules with a diameter of up to 40 mm. It can be homogeneous, from granules 5-10, 10-20 or 20-40 mm, or it can consist of elements of different sizes.
Note! Grain sizes and other characteristics of the material are regulated by GOST 32496-2013. Manufacturers producing it according to their own specifications cannot guarantee quality.
This bulk material also differs in density, which depends on the size of the granules and voidness. The lower these figures, the greater the weight.
For thermal insulation, expanded clay is used for the floor in the form of crushed stone or gravel. Sand is not suitable for this, as it has a high density. It is used when it is necessary to level bases with a large difference in level or damaged surfaces as a material that gives less shrinkage.
Ways to install expanded clay screed
Expanded clay for leveling and thermal insulation of bases can be used in loose form or as a filler for a filling mixture. Depending on this, the technology of work also changes.
Wet method - traditional screed
A screed made of expanded clay concrete is made in the same way as a classic one, from a sand-concrete mixture. It's just that not ordinary crushed stone or gravel is used as a filler, but expanded clay. It allows you to seriously alleviate the load on the floors when a large screed thickness is needed: about 50 kg per square meter with a thickness of 5-6 cm.
In this case, the fractionation of the material is not particularly important, since the voids will be filled with sand, and all the components of the solution will bind into a monolith. Therefore, you can take both crushed stone and gravel, focusing on the availability and cost of the filler. Crushed stone is usually cheaper due to its lower density and weight.
It is also worth considering that the smaller the size of the aggregate granules, the smoother the surface will be. A layer with large gravel will probably have to be leveled with an additional cement mortar, making a finishing screed. A gravel layer may well serve as a ready-made base for laying tiles, but you cannot lay linoleum or laminate on it - you will also need to level the surface.
Advice! Using a large aggregate for a screed device on the ground, its surface must first be leveled and compacted, without leaving significant irregularities and dips.
The composition of expanded clay concrete, the proportions per 1 m3 depend on the brand of cement used and the requirements for the strength of the base. For a house or apartment, an approximate ratio of M400 cement, sand and expanded clay is usually used 1: 3: 2. Such a composition gives a brand of screed M50-M100 sufficient for domestic conditions, taking into account the laying of the finishing floor covering.
Video description
You can study the technology of the expanded clay concrete screed device using the video:
The work consists of several stages.
- First, the walls mark the level to which the floor rises. To do this, it is most convenient to use a laser level.
- After removing the old flooring and cleaning up the garbage, they fill up and tamp holes in the ground, close up large cracks, cracks along the walls and joints between the plates - preparatory work dependent on the material and condition of the substrate.
- The next step is waterproofing. It is needed so that during the solidification of expanded clay concrete, moisture does not leave it. And also to prevent leakage from the wet solution to the lower floors. In the case of a screed on the ground, waterproofing also acts as a barrier to ground water. It is made of a thick film, roofing felt or fiberglass, be sure to lay the material with an overlap of at least 10 cm and glue the joints with tape. concrete foundations can be isolated liquid formulations- waterproofing, liquid rubber, etc. The waterproofing layer should be continuous and go vertically onto the walls above the marking level.
- If the floor is laid electrical cables, they are also wrapped in foil and wrapped with tape.
- Next, beacons are installed, fixing them with cement mortar or alabaster. The distance between the beacons should be no more than the length of the rule.
- Along the entire perimeter of the walls along the marking line, a damper tape is glued or fixed in any other way. It levels the thermal expansion of the screed and serves as sound insulation. You can use both ready-made self-adhesive tape and other suitable materials- for example, strips of foam.
- Then, expanded clay concrete is prepared, the proportions of which are selected in accordance with the requirements for strength. In the case of an insulating screed and laying a hard floor covering on top of it, it is allowed to double the amount of expanded clay.
- When preparing the solution, it is recommended to first pour expanded clay with water so that it absorbs moisture, does not float to the surface of the screed and does not pull it out of the solution. Then add the remaining components - cement and sand or a ready-made sand-cement mixture.
- If the thickness of the screed exceeds 60-100 mm, then it is poured into 2 layers with a minimum exposure between the layers. It is best to divide the room into squares and fill each section in 2 steps, and then move on to the next one.
- If the screed is without a leveling layer, then the solution is pulled out by the rule along the beacons. In the case of a cement screed, a place is left for it - at least 2-3 cm to the upper level of the lighthouses, and expanded clay concrete is leveled by eye.
- After the initial setting of the solution, the beacons are removed, and the resulting recesses are sealed with a fresh solution.
It is possible to increase the strength of the expanded clay concrete base by laying a steel reinforcing mesh between the layers. But this is not a required option.
You can level the surface for laying linoleum, parquet or laminate as you would with a conventional cement mortar, and self-leveling bulk mortars. They can be poured after the main expanded clay concrete layer gains sufficient strength and matures - after about 5-7 days.
In order for this process to proceed normally and not be accompanied by the appearance of cracks, the surface is covered with a film, and in the early days it is periodically moistened with water. This is necessary to maintain the required amount of moisture, which expanded clay quite actively absorbs.
Dry screed
The fastest, most effective and easiest floor insulation with expanded clay is performed using dry material, on top of which gypsum-fiber sheets are laid. Dry screed can be produced in two ways: frame and frameless.
In the first case, the base is laid according to the level wooden logs, and between them, expanded clay is simply poured, which serves as a heater. Perfect leveling is not required, the main thing is that the material does not lie above the frame. Sheet material (plywood, chipboard) or boards are subsequently mounted on it.
The frameless method requires the use of quality expanded clay with a certain particle size, and careful leveling. It is best to take gravel of different fractions so that small granules fill the voids between larger ones well. The ideal choice would be special ready-made fillings such as Keraflor or Compavit from Knauff.
Dry expanded clay backfill for prefabricated floor Source ecovix.ru
In any case, it is necessary to first perform preliminary work, including garbage collection, sealing base defects, leveling, and laying a damper tape, which were described above. Waterproofing is required only if there is a possibility of moisture penetrating the backfill from below. For example, from the basement.
The floor of expanded clay and gypsum-fiber sheets is mounted as follows:
- backfill of the required thickness is poured onto the base;
- since there should not be beacons in a dry screed, then 2 guides are laid out parallel to each other on the backfill, which, using a level and a square, are set to a horizontal position at the level of the markings on the walls. To do this, a dry mixture is poured under them or the highly raised end of the guide is sunk;
- laying the rule across the guides, the backfill is carefully leveled. Before that, on one side of the rule, corners are cut to the thickness of the guides so that there are no pits in their place;
- GVL sheets are laid on the prepared surface, smearing the mounting ledges with glue and combining them. Self-tapping screws are used for additional fixation.
Video description
The whole process from backfill to laying the coating is shown in the video:
Advice! It is better to start backfilling from the far wall and move to the exit, and laying the GVL in the reverse order. But it is possible to carry out installation in small sections or move along a temporary flooring from GVL thrown on expanded clay.
Combined method - typesetting screed
Something in between the described options is a screed on expanded clay, covered with a thick layer on the base. To provide effective thermal insulation, the thickness of the backfill layer must be at least 100 mm and consist of gravel of different fractions. If only leveling is required with raising the floor level, the layer of dry expanded clay may be smaller, and the backfill may consist of fine gravel and sand.
So, a screed with expanded clay - the technology of its manufacture with all the variations:
- as usual, the first step is to mark the level and prepare the base;
- expanded clay is poured and distributed so that there is room for cement screed(usually at least 20-30 mm);
- so that the backfill does not float into the screed, the expanded clay layer is poured with cement milk - a liquid solution that must seep between the granules and fasten them together;
- a day later, beacons for a wet screed are installed on the seized layer;
- between the layers, you can lay a reinforcing mesh, which is important for large areas, or a thick plastic film, which will prevent expanded clay from sucking water out of the solution. In this case, spilling the backfill with a liquid solution is not necessary.
Video description
In the following video, all these steps from backfill to rough screed are shown in detail:
The final stage is the installation of a classic screed for lighthouses. It can be prepared from cement and sand in a ratio of 1: 3 or use a ready-made sand-cement mixture.
Conclusion
There are several ways to level and insulate the floor with expanded clay in a cottage or private house. Each has its own characteristics and reasons for use. But any of them is available for independent execution. And in order to get a quality result, you need to strictly follow the technology, without neglecting any of the recommendations regarding both the choice of material and the sequence of work.
Expanded clay is a natural material obtained as a result of high-temperature processing of clay, it is used to level the floor. It is believed that a floor screed with expanded clay is the easiest option for repairing a floor covering, but, nevertheless, requiring compliance specific technology so that the floor lasts for a long time.
Filling the floor with expanded clay. Positive traits
Expanded clay combines such positive qualities:
- ease;
- practicality;
- environmental friendliness;
- strength;
- thermal insulation;
- soundproofing.
If we compare expanded clay in terms of strength with cement and sand, we can note the clear advantages of the first.
Expanded clay floor screed is one of the easiest floor leveling options.
Expanded clay screed, despite its incredible strength, retains the following abilities:
- passes air and steam;
- resists frost and extreme heat;
- does not ignite;
- does not rot;
- does not rust.
An important factor is the ease of transportation of expanded clay to any floor of an apartment or a private house.
What will be required at work?
Materials and tools:
- expanded clay;
- cement;
- sand;
- water;
- gypsum fiber sheets (GVL);
- laser level (water level is also possible);
- metal slats as beacons (metal profile);
The choice of type of screed depends on the surface of the base and the characteristics of the room. - self-tapping screws for fastening beacons;
- screwdriver;
- polyethylene film;
- roulette;
- putty knife;
- mixer.
Preparation for pouring the floor with expanded clay
Procedure:
- It is necessary to get rid of the previous coating (linoleum, parquet, laminate, tiles, etc.) and clean the resulting surface from debris.
- Using a hammer, you can determine the degree of delamination of the old concrete screed. All delaminations must be removed so that even dust does not remain, for this you can use a vacuum cleaner.
- Further, a primer is recommended using a ready-made deep penetration primer in a liquid consistency. This contributes to the strong adhesion of the old coating to the new screed. In the case of a weak base of the old screed, it should be primed twice.
After the primer dries, you can proceed to the stage of marking the desired floor level.
Especially often used in cases where it is necessary to significantly raise the level of the floor Waterproofing is an important step before pouring the floor
Waterproofing is a protective layer that prevents the penetration of moisture from the basement or apartment from below. If you do not do waterproofing, then the penetration of moisture of any nature will lead to swelling of the layer of sand or expanded clay, and this will ruin your even screed.
To protect the expanded clay screed, you can use:
- polyethylene film;
- glassine (paper with bituminous impregnation);
- waterproofing materials.
Strips of film should be laid with an overlap of 15-20 cm. To prevent their separation, you can use adhesive tape. It is important to lay the film so that it also goes onto the walls with a height of the future screed by about 7 cm.
How are beacons placed?
The device of a screed with expanded clay of the dry method is carried out by installing beacons and pouring out a pillow between them. The prepared surface is rammed and covered with GVL sheets. Slots from the dismantling of beacons are sealed without fail to prevent the penetration of moisture.
When applied cement mixture beacons are also mounted in the prepared surface and expanded clay is poured, which is poured with cement milk. After drying, the finished surface is poured with concrete. This allows you to save money.
Good to know
There are 3 types of expanded clay, the density of which varies from 250 to 600 kg / m3:
Expanded clay is an environmentally friendly material, very light and practical, as well as very durable, with a high level of heat and sound insulation. - expanded clay sand. It is convenient to use for thin screeds (no more than 5 mm);
- expanded clay gravel. It happens: 5-10 mm, 10-20 mm and 20-40 mm. It is used for the installation of durable and lightweight floor coverings;
- expanded clay-crushed stone 10-14 mm. It is most commonly used in the concrete preparation process.
Which type is needed depends on the room that needs a screed and on the chosen laying technology.
When is a floor screed with expanded clay needed?
Laying technology is relevant in the following cases:
- screed thickness of 5 cm or more. Due to its lightness, expanded clay will reduce the load on concrete pavements and on the wallet;
- it is necessary to increase the thermal conductivity;
- in rooms with high humidity;
- as a base for laying ceramic tiles, laminate, parquet, linoleum;
- there is a need for hidden communications;
- it is necessary to insulate wooden coverings;
- the building is old, the expanded clay screed device will help not to overload the ceiling.
It is quite easy to lay a floor screed with expanded clay on your own, but it is important to listen to the recommendations of experts:
- wires passing under the screed must be wrapped with polyethylene and fixed with adhesive tape;
- as beacons it is more convenient to use metal profiles or slats;
- the final version of the screed on expanded clay should be left to dry for a month;
- systematically moisten the finished surface with water in order to avoid the formation of cracks;
- you can add to the final mortar, which can prevent the formation of concrete cracks. In this case, it is better to clarify with a specialist;
- you can walk on the finished surface already on the 8th day, but the screed will gain the desired strength after the 1st month;
- filling the floor with expanded clay should begin before installing any plasterboard structures, ceilings, any materials that actively absorb moisture.
Having studied the recommendations, the task will no longer seem difficult. Without having professional skills in laying expanded clay screed, you can cope with the work yourself, after watching the training videos on the Internet.
During operation, depending on the intended purpose, a number of technical requirements. These are strength, evenness, the maximum value of the specific load, the degree of thermal insulation, and so on.
General description of expanded clay concrete
An excellent option in terms of price, quality and speed of installation of the floor surface is the laying of a concrete screed, which provides perfect evenness and high wear resistance. However, this type of floor has a number of disadvantages - a high specific gravity per unit area and a low degree of thermal insulation over the entire depth of the surface. Expanded clay concrete screed, which is a lightweight concrete, retains the advantages of a conventional concrete screed, but is devoid of its disadvantages.
The method of obtaining expanded clay concrete for floor screed is simple and differs from the classic concrete mortar, consisting of cement, sand, water and crushed stone, only in that expanded clay is used instead of crushed stone. It has the form of gravel with a porous structure in the form of an oval of various fractions from 5 to 40 mm, it is produced industrially, by firing clay or its derivatives. Variability is determined by the type of implemented construction works. The smallest one is used for the production of expanded clay concrete screed and the production of blocks, the middle one is used for bulk insulation of the floor and ceilings, the large one is used for thermal insulation of outbuildings and heating mains.
Types and scope of expanded clay concrete
The classification of expanded clay concrete is quite extensive and depends on the requirements for the type of product produced, the density of the granules, the application and solidity. All these signs are standardized by the brand (for example, expanded clay concrete M100), which determines the class of its application and varies from 35 to 100 kg / cm²:
Claydite concrete grade | Application area |
arrangement of load-bearing structures, the construction of partitions indoors |
|
erection of load-bearing structures in the construction of residential and industrial buildings |
|
floor screed |
|
production of expanded clay concrete blocks |
|
And floor slabs |
|
installation of engineering structures with a large periodic load |
Taking into account the area of application, the density of expanded clay concrete is an important characteristic, which is determined by the ratio of mass to volume of the material and has limits from 700 to 1400 kg / cm². Often in buildings old and not very old building for a number of reasons (foundation subsidence, unskilled installation), there are significant differences in the floor level of adjacent rooms, and sometimes even within the same room. Leveling to a single level with a conventional cement-sand screed can seriously increase the load on the supporting elements of the building, which is highly undesirable, especially when it comes to multi-storey buildings.
Due to the porosity of the screed, the density of heavy concrete is much less, which determines the unconditional priority of its use in such a situation. Increasing the percentage of cement in expanded clay concrete increases the strength of the structure, however, there is a significant increase (up to 1.5 times) in the weight of concrete. Accordingly, the maximum possible reduction of the cement component of the material allows to reduce its volumetric weight. In this regard, the grade of Portland cement used in its production must be at least 400.
Benefits of using expanded clay concrete
And it does not sink in water, and does not burn in fire. Low thermal conductivity determines the high heat resistance of expanded clay concrete, which means long-term resistance of the material to high temperatures. Even at temperatures above 1000 °C, expanded clay concrete retains its mechanical properties. The material shows itself very well when exposed to moisture. Unlike stones, which, having been soaked with water in frost, are destroyed, expanded clay concrete has high frost resistance, that is, the ability to repeatedly freeze and thaw without loss of strength.
Another important factor determining the priority choice of expanded clay as a filler for concrete is its environmental friendliness. It does not emit harmful substances when exposed to aggressive environment, neither with the passage of time, nor with complete destruction. This explains its choice as building material and insulation in living quarters.
Preparation of the base for pouring the floor with expanded clay concrete
If the screed is made over an existing even and dense coating, then this stage of work can be skipped. However, most often pouring is performed directly on the ground, in which case additional preparation of the base is required. The surface is leveled and carefully compacted, the pits are covered with sand, the protrusions are knocked down for uniform laying of the pillow. The pillow is a layer of sand about 2-3 cm and a layer of expanded clay or crushed stone 3-5 cm thick, or more, up to the level of the draft base. Next, a polyethylene film or roofing felt is laid to waterproof the future screed, a masonry mesh is mounted and beacons are installed.
Types and methods of using expanded clay screeds
Having understood the basic properties and technical specifications expanded clay concrete, its pros and cons, let's try to understand how to properly fill the floor using this material. The choice of the type of expanded clay concrete screed depends on the type of base on which it is produced, and therefore floor screeds can be of three types. Let's consider each of them.
Dry screed
Expanded clay gravel is evenly and without being distributed over the previously prepared, cleaned and compacted base surface, not reaching 2 cm to the lower level of the lighthouse. in this case is determined by the required degree of thermal insulation. Next, the entire area is poured with cement milk, which is made by mixing cement with a large amount of water without adding sand. This procedure will fix the expanded clay and cover the gravel with a thin protective layer that prevents moisture from being drawn out of the finishing screed, which will give additional strength to the floor. After that, the usual thin screed is performed. The advantages of this method are the speed of installation, the disadvantages are low surface strength.
Wet screed
With this option, so much water is added to the solution so that light and porous expanded clay floats to the surface after pouring the screed. The hardening of concrete takes a little longer, all the filler is concentrated at the top of the screed. The advantages include self-leveling of the mixture. The disadvantages are long drying, the need for special preparation of the surface to be coated in order to avoid leaks, as well as the subsequent surface screed, if necessary, to obtain smooth surface. In this way, attics and outbuildings are usually insulated.
Semi-dry screed
The most common type of expanded clay concrete pavement, which is identical to conventional concrete in terms of the manufacturing method. For the correct filling of the floor in this way, expanded clay concrete M100 is used. In its manufacture, expanded clay of the first fraction with a diameter of 5-10 mm is taken. The proportions of the mixture are as follows: 1 part of Portland cement grade 400 - 3 parts of sand - 4 parts of expanded clay. As for the amount of water, this parameter must be selected individually, depending on the moisture content of the sand. It is necessary to achieve a consistency in which the granules of the material would not float to the surface, which makes smoothing difficult, at the same time, the solution should not be too dry, as this complicates its installation and can lead to the formation of voids and cracks in the mass of the screed.
The solution is mixed in a concrete mixer or in a large container. The use of a mixer nozzle is extremely problematic due to small portions in one batch, and this makes laying long, the solution turns out to be of different consistency, and expanded clay is distributed unevenly in the mass of concrete. The sequence of mixing the ingredients in different sources described in different ways, but in practice it does not matter. The main thing is that the solution is uniform and the expanded clay granules are completely covered with a binder.
The solution is applied in an even layer over the entire surface to be covered, while it is necessary to observe the condition - the thickness of the floor screed made of expanded clay concrete must be at least 3 cm, usually it is 4-6 cm. its grouting a day after laying. The advantages of this coating method are obvious - the possibility of using it for any type of floor and ceiling. The disadvantage is the high labor intensity, pouring using beacons and the need for finishing grouting.
In the harsh conditions of our country with traditionally frosty winters, many people think about insulating their houses and apartments: they thicken and compact walls, floors, ceilings. Technologies are improving year after year. The range is constantly replenished with various mixtures, dry fills and heaters. One of the solutions for floor insulation is the use of expanded clay screed.
Peculiarities
The floor screed is the first layer above the base. Choose it based on the type of premises, the purpose of its use, the condition of the house and the intended decorative coating gender. Expanded clay has been known for a long time, but does not lose its relevance and popularity as an additive in modern screeds. Mixtures sold in stores do not lose their properties when using it. This material is made from clay, purifying it of unnecessary impurities. Porous granules are formed from a solution of a liquid consistency under the influence of high temperatures.
Pros and cons
To use a screed with expanded clay, you need to understand what the advantages of this method are, why you need to do this at all.
- This screed allows you to significantly increase the height of the floor. In cases where it is necessary to raise the level to a considerable height due to distortions of the base or simply to reduce the distance between the floor and the ceiling, it is not advisable to pour a thick layer of concrete.
- In old houses and structures with wooden floors even with a small layer of pouring, the base may not withstand the load of the concrete solution. Filled floors in this case minimize the risk of damage to the floors.
- Even strong drops, pits and cracks can be filled with expanded clay composition and a flat surface can be obtained.
- In cold climates, an important plus is the frost resistance of expanded clay.
- The safety of use is determined, among other things, by resistance to heat.
- The material is very durable - it does not corrode, does not burn or rot.
- For the environmental qualities of the coating, excellent vapor and air permeability is required.
- Despite the natural basis, expanded clay screed is not affected by microorganisms, fungi, mold and rodents.
- Due to its light weight, the material can be transported without any problems even in large volumes.
- Laying technology allows an unprepared person to cope with the work. Handling the composition is quite simple.
- Expanded clay additives are very budgetary. The product is easy to find in stores. Often, those whose choice falls on the purchase of expanded clay do not want to isolate the coating, but save on the screed, because concrete mixes are quite expensive.
- The material is moisture resistant. Its water absorption reaches 20%. This means that when flooded, long time does not deform.
- If you need good sound insulation, then the choice should definitely fall on expanded clay. At the same time, unlike expanded polystyrene and foam plastic, it has greater strength and lower thermal conductivity. The best sound insulation is achieved by adding expanded clay to concrete.
Expanded clay screed has not so many disadvantages:
- If you are making a dry screed, you need to protect the base from water penetration. It will not be absorbed, creating dampness and mold in the room. Waterproofing is always given great attention when finishing with expanded clay.
- Avoid single granule size when dry-filled. Heterogeneity will give greater density and uniformity to the coating.
- To retain heat, small granules will be useless, like a narrow layer of screed. It is necessary to raise the floor level by at least 10 cm.
Technology
First of all, you need to prepare all the tools and calculate the required amount of materials.
You may need:
- bucket;
- mixer, construction mixer or just a stick;
- brush or needle roller;
- spatulas;
- rule;
- construction beacons;
- building level (water or laser);
- ruler and special marker;
- brushes and rollers.
On the initial stage prepare the subfloor. If you are doing repairs in old apartment or at home, carefully remove the old screed with a crowbar or perforator. Next, you need to get rid of debris, dust and pollution. Estimate the opened base. It should not have chips, cracks, greasy spots. If you find gaps more than 1 mm wide, they must be sealed.
- cement-sand mixture;
- putty or sealant.
Deep penetration priming is necessary for the mixture to properly bond to the substrate surface. Grease spots should be removed or cleaned. Next, treat the entire surface of the floor, using the composition for the primer.
The next step is to choose zero mark. This is the definition of the height at which the top layer of the flooring we are creating will be located. This can be done using laser or water levels. As a rule, it is set no higher than 15 cm from the base. The flooring device involves laying a waterproofing layer. It may seem to many that in the living rooms in the apartment this stage is optional, but it is not.
Waterproofing can be done in several ways:
- If you live in a private house, it is better to use the well-known roofing felt installation. Overlap the layers, leading to a certain height on the walls. The base is pre-greased bituminous mastic for gluing roll material to him. The seams also need to be treated with mastic.
- In apartments, it is enough to apply insulation with a film. Choose dense materials for layer strength. The film is also fixed with an overlap and with a call to the walls. Glue it with construction tape. To minimize the impact of the coating layers, the perimeter of the room is pasted over with a damper tape.
- You can also use coating waterproofing from special mixtures diluted in water. They process the entire surface of the floor and the bottom of the walls.
The thickness of the layer is indicated in the recommendations on the packages. Next, you need to let the coating dry. This will take more time than the previous methods. Then the laying of the expanded clay concrete layer is carried out. When the coating is completely dry (drying time varies depending on the composition of the concrete mixture), you can proceed to the fine finishing of the floor covering.
Backfill types
An important indicator in relation to expanded clay is its density. It depends on the size of the applied fraction. In construction, GOST 32496-2013 is used, which regulates technical features expanded clay granules, but due to optional certification, manufacturers can produce various options according to their specifications.
The most common division into:
- Expanded clay gravel. The size of the granules is large - 20 - 40 mm. The lightest backfill is obtained from granules of this size.
- The gravel is smaller. Its particles have sizes from 10 to 20 mm. They are usually obtained by crushing gravel.
- Expanded clay sand less than 10 mm in size. All expanded clay remains fall into this category.
If we talk about the thermal insulation properties of expanded clay, then it is advisable to use gravel and crushed stone, and use waste to obtain a more porous coating.
Filling methods
In total, there are three ways of screed using expanded clay. It is necessary to analyze the method of use and the advantages of each of them in more detail.
Semi-dry screed with expanded clay
This method is used in cases where it is necessary to both raise and insulate the floors in the room. To achieve thermal insulation, the expanded clay layer must be at least 10 cm. Here it is important to take a large fraction of the backfill - at least 20 mm. If it is only important for you to raise the floor to the required level, you can use smaller particles. In this case, waterproofing is necessary in order to protect the expanded clay layer from moisture. Beacons are set to the required height, and expanded clay is backfilled. Walk on it with a rule to tamp and level the layer.
After that, you should transcend to pouring the concrete screed. A cement-sand mortar or a special mixture can be used. For the convenience of work, it is better to pre-spill the expanded clay layer with a concrete mixture, highly diluted with water - cement milk. This will prevent the expanded clay grains from floating up and make it easier to fill with the main solution. Also for these purposes, laying a layer of granules with a film may be suitable. Only in this case, the laying must be done very carefully so that the film does not tear.
These two methods are also necessary so that the moisture from the concrete layer goes less into the porous expanded clay granules. Then the coating will be more reliable and durable. For pouring concrete mortar, you can use a reinforcing mesh. This will make it easier to gradually, in sections, fill the layer and level it to obtain a smooth surface.
Expanded clay concrete
This is the so-called wet screed. In this case, it is necessary to carefully measure all the irregularities of the base and determine how thick the screed layer will be. This method is advantageous to use if you have to raise the floor level to a considerable height, as well as to save concrete mix. Expanded clay is combined with sand concrete, carefully stir the resulting composition and distribute it over the floor. It is better to soak the expanded clay granules with water first, so that later the consistency of the mixture does not turn out to be too dry. Mixing is best done with a construction mixer, because no spatulas and sticks can achieve a uniform consistency without clots and lumps.
To reinforce the expanded clay concrete screed, you can use a reinforcing mesh, and as beacons - any slats that are easiest to get. The mesh should not reach the required height level by a couple of centimeters. Next, distribute the solution evenly over the grid, leveling it with a rule. After finishing laying the mixture, do not wait until it dries. Prepare a solution for the top leveling layer. It could be cement-sand screed, and bulk floor. It is applied already to the zero mark, leveled with a rule and left to dry.
After about a day, it is necessary to remove the beacons. Be sure to treat the openings from them with a primer and fill with cement. The advantage of the expanded clay-cement screed is that it can be poured without problems with your own hands, all proportions are made by eye until the necessary viscous consistency is obtained. Such a screed can be part of a multi-level system and be used as a draft under the self-leveling floor. It may also be sufficient for laying a fine finish that does not require an even subfloor (such as a tile floor).
Dry floor screed with expanded clay
If the semi-dry method is a combined screed, then backfilling with expanded clay granules does not require subsequent pouring with any solutions. The base is prepared as usual, but any possibility of moisture entering the waterproofing layer must be excluded. Lighthouses are exposed to a necessary mark. The minimum thickness of the expanded clay layer with this technique is 5 cm. The granules need to be selected in small or medium sizes, it is advisable to combine different sizes to distribute the layer more evenly with fewer voids. It makes no sense to use small waste, because they will require a huge amount, but they will not create the desired thermal insulation effect.
The surface is best divided into strips using wooden slats– so it will be easier to level the granular layer, and lay the following materials. Do not tamp the expanded clay, but gently roll it out. Next, a layer of moisture-resistant drywall should be laid. If the sheets are thin, it is better to lay them in two layers, gluing them together, and the seams must be coated with putty. You can also use waterproofing mixtures. After the drywall installation is complete, cut off any protruding pieces of tape or film.
This type of screed has a lot of advantages:
- The smooth surface is suitable for applying any kind of finishing coatings.
- The layer can withstand high loads.
- The floor covering is quite light, so it can be used on old dilapidated floors without any risk.
- Thermal insulation is top notch. No device needed warm floors on a keramzite pillow.
- The work can be completed very quickly, and immediately after completion, proceed to the next stages of repair.
- Dry screed provides excellent sound insulation.
- The cover does not warp.
Sometimes builders suggest using expanded clay for pouring into a rough screed directly on the ground instead of sand or gravel. This can only be done if the water table is low, otherwise high humidity will lead to negative consequences for the entire climate in the house, and good heat storage will no longer play its role here.
Layer thickness
The thickness of the coating will depend on many aspects: the size of the granules, the level of floor elevation required, and the functionality of the screed. It is better to take a minimum layer of screed using expanded clay at least 3 cm. Depending on the method of coating, the layers can vary greatly. For pouring with expanded clay concrete in order to raise the height and level, a thickness of 3-5 cm will be enough. If you want to get a heat-insulating effect, the layer should be at least 10 cm.
A light screed with a thin layer fits better with the use of small granules. This saves money and reduces workload. In the case of dry backfill, fine fractions of 3-6 mm can be used to level the floor, but for thermal insulation it will be necessary to lay a layer of special materials. If you are primarily interested in heat-saving properties and anti-noise effect, then you need to fill up 10-15 cm from the base, and take large fractions.
How long does it dry?
This question concerns the wet and combined type of screed. Sand concrete takes a long time to dry. With a mixed type of screed, you must wait at least 14 days for the top layer to dry in order to continue finishing work. Full strength and ability to perceive the maximum load will gain the coating in 28 days. However, these recommendations vary depending on the thickness of the layer. If you used the wet method, and the thickness of the screed is more than 5-6 cm, then you need to increase the period to 6 weeks. In any case, if you are in doubt about the drying time of the coating, cover the floor area with a film and press it in several places with wooden slats.
If condensation appears after 1-2 days, the screed must be dried further, because if all the accumulated moisture does not have time to evaporate, then the strength and integrity of the coating will be at risk. Such a floor will no longer be reliable and durable. If you prepare a mixture with the addition of modern components or special plasticizers, then this increases the chances of obtaining a high-quality surface and, of course, reduces the drying time, sometimes even by half. Information is usually indicated on bags with ready-made formulations. This method is more expensive, but more guarantees are given. It is only necessary to choose high-quality mixtures of trusted manufacturers.
How to calculate the expense?
Expanded clay consumption for different rooms will depend on the strength of the base and its maximum load, layer thickness, your preferences for heat and sound insulation. The more expanded clay you add, the more heat the coating can retain, but the strength will suffer. For a wet solution, it is better to take expanded clay backfill and concrete in proportions of 1: 1. The amount of granular material is measured in liters, not kilograms. Usually, a layer 1 cm thick is taken for calculations. It is necessary to determine how many liters of expanded clay are needed to cover 1 square meter. m area. This value will be equal to 10 liters.
To find out the consumption of expanded clay for the standard area of \u200b\u200bthe apartment (usually 20 sq. M is taken), you need to multiply 10 liters by 20 sq. m. It turns out 200 liters. The layer height is chosen based on the purpose of the room. On the ground floor and in cold rooms, a height of 10 cm is chosen; in other types of housing, a layer is taken from 3-4 cm. Thus, in a new building in one-room apartment with an area of 40 meters, you can apply a layer of 5 cm. So, for 1 sq. m will account for 50 liters of expanded clay. Therefore, the entire area of the apartment will require 40 * 50 \u003d 2000 liters - 40 bags of 50 liters.
Kitchens in "Khrushchev", having a small area, require a layer of 3 cm or more. For such a room, you will need from 150 liters of expanded clay. It must be remembered that surfaces may have irregularities and deviations, so the calculation formula is only approximate. It is better to take expanded clay with some margin. For pouring a layer of concrete, the approximate consumption per 1 cu. m of expanded clay will require 300 kg of cement "M500" and the same amount of sand.
Screed - a layer of the floor that precedes the floor covering.
From the purpose of the room, the condition of the base, what material is chosen for flooring, determine the type of screed.
The screed levels the surface under the floor, insulates the floor if necessary, makes sound insulation, and provides the last layer of the floor with a design mark.
Properly selected screed makes the floor strong and durable.
The screed has a height of 3 to 20 centimeters, so it is used when the base should be leveled under the floor with a height difference of more than four centimeters.
The same feature makes it possible, if necessary, to make, or improve, by arranging such a screed under the floor on the interfloor floor.
In no case should such a screed be used over a warm floor, as you know, and its use will lead to thermal insulation and the screed will simply not let heat through.
If the base under the floor has a mark much lower than the design mark, the expanded clay screed makes it possible to raise the layer to the desired height.
Apply this type of screed before, parquet, tiles. Used indoors and outdoors.
Peculiarities
The popularity of using this type of screed is due to a number of positive properties of expanded clay - the main material of the layer:
- The small specific gravity of expanded clay, on average 0.95 g/cm3, makes the screed light. In cases where a thick underlayment is required, expanded clay screed is indispensable.
- The moisture content in the room is regulated, because expanded clay, having a natural origin, breathes as part of the screed.
- It is not subject to corrosion: it does not burn, does not rot, is not afraid of chemical attack.
- The porosity of expanded clay gives the screed a weak thermal and sound conductivity. Therefore, it will insulate the floor and protect against noise.
- Expanded clay has a heavy-duty shell and delegates strength and reliability to the screed.
For the screed take expanded clay fractions from 5 to 20 millimeters. It is recommended to take two different sizes grains for greater backfill density.
Device
- Foundation preparation.
You will need: hydraulic level, building level, broom, scoop, trowel.
The old floor is being dismantled, if any. The base is cleared of debris, concrete flows. If there are holes, rusts, they are filled with a cement-sand mortar. If on the floor of communication, then they are wrapped plastic wrap, securing with adhesive tape.
The foundation needs to be waterproofed. There are several options for doing it:
- Hydroisol is applied with a blowtorch.
- With a brush, coat the base and part of the wall with waterproofing mastic in two layers to the height of the marks on the wall plus five centimeters. The second layer of mastic - three hours after the first.
It is possible to perform waterproofing with polyethylene film, 2 mm thick or more. It is laid on the base and brought to the walls 10 centimeters above the level of the planned screed. The joints of the film are glued with a wide adhesive tape.
- We install beacons, perform a screed
A very important question: How is the floor level in different rooms combined?
For example: the thickness of the layer of laid parquet is 30 millimeters, the thickness of the tiles is on average 9 millimeters, which means that the height of the screed in the room where the tiles are planned to be laid should be 21 millimeters higher than in the room where the parquet is planned.
This is done in order to avoid thresholds and make the floor at the same level in adjacent rooms.
Before backfilling expanded clay, the thickness of the layer is determined: from the base and two centimeters below the upper edge of the lighthouses, this difference will then be filled with a cement screed.
Expanded clay falls asleep between beacons, leveled with a rule, focusing on a previously determined mark.
The surface of expanded clay is lightly tamped with a pusher or feet, walking back and forth, and spilled with “cement milk” - equal parts of cement and cement-sand mixture are diluted with a large volume of water to the consistency of milk.
Thanks to this, the surface of the expanded clay layer will become hard, and it will be possible to walk on it.
A day later, a screed is performed on the basis obtained. The composition of the cement-sand mortar:
- sand - 3 parts,
- Portland cement 400 - 1 part.
Cement-sand mortar is poured to the upper edge of the lighthouses, leveled with a rule. The solution dries for 14 days until completely solidified:
- A day later, when it seizes, the beacons are removed, traces from them and other irregularities are filled with cement-sand mortar and rubbed with a trowel.
- After two weeks, you can lay the top coat on the screed.
And the screed will be ready to carry full loads after 28 days.
Another way
Expanded clay screed, as in the previous case, has two layers.
The main difference is that the first layer does not consist of dry expanded clay, subsequently poured with a weakly cement mortar, but a mixture of expanded clay with a cement-sand mortar, that is, expanded clay concrete, is immediately used.
The proportions of the components of expanded clay concrete:
- 8 pieces of expanded clay,
- 3 parts sand
- 1 part cement.
This method is convenient in that it is possible to make expanded clay concrete directly at the site of the floor installation, on any floor.
- Expanded clay is poured into the container, water is poured in enough to wet all the expanded clay. You will need a mixer for mixing.
- Sand, cement are added, you can take the finished mixture.
- Stir again.
The mixture is kneaded correctly if it is thick, homogeneous and without lumps. If the mixture is too dry, not enough water has been added.
Spread the mixture between the beacons to the calculated mark: leave two centimeters for the second layer to the top of the beacon.
The second layer, the usual screed, as in the first method, is applied immediately to the first without a technological break for drying. This is the advantage of the second method and its main feature.
Fill the strip between the beacons:
- the first layer is expanded clay concrete,
- followed by the second - a screed, then the next strip between the beacons is also filled, and so on.
It is important to make the alignment of the second layer very carefully. Expanded clay screed will acquire the necessary strength, as in the first method after 28 days.
Practice tips: some nuances and possible errors.
Cement-sand screed (second layer) after completion of work and until completely dry, it needs to be moistened with water to avoid cracks.
If liquid is added during the preparation of the cement-sand mortar, then moistening the surface of the screed during hardening is not necessary.
A glass jar will help to establish whether the screed has gained strength, whether it has dried out enough:
Turn the jar upside down and put the neck on the surface of the screed, if the jar fogs up, it means that the screed is not ready for use, it has not dried out yet.
Neglect of exact observance technological process production of expanded clay screed, violation of the technological breaks for hardening layers - can lead to irreversible consequences.
The floor screed device with expanded clay is a reliable basis for any type of floor covering, it will improve the ecological climate in the house.
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