Cement expanded clay screed. Floor screed with expanded clay: pros and cons. Self-leveling coating on expanded clay screed

Expanded clay concrete is the same cement mortar that is used to fill the screed. But since it is not heavy crushed stone that is used as a large aggregate, but expanded clay granules, the floor is warmer. Expanded clay is quite fragile and not suitable for full leveling of actively exploited surfaces. Its main purpose is to create a light heat and sound insulating layer that does not significantly increase the load on the base.

To make expanded clay concrete with your own hands, you will need expanded granules with a size of 5-10 or 5-20 mm with a bulk density of 600-700 kg / m3. Fine sand is not so effective, but it is used for fine casting up to 30 mm. Coarse fractions are often used for dry and semi-dry screeds. The final choice depends on the loads on the future floor:

1. The best results are shown by mixtures where all grain sizes from 5 to 40 mm are present in equal proportions. In this case, the screed turns out to be a little denser and heavier, but rather strong. At the same time, cement consumption is reduced.

2. To reduce the load on the floors, expanded clay is chosen larger. A finished screed with a large thickness can shrink over time, but this is the only way to even out serious surface drops, reaching 10-15 cm.

3. With a small thickness of concrete and the need to get rid of shrinkage phenomena, there is only one option - fine expanded clay sand.

As for cement, it is impossible to save here, since it only depends on it how tightly the expanded clay granules adhere to each other. At a minimum, it should be a binder with the M400 brand strength, but the more expensive PC M500 can also be used. The main thing is that Portland cement goes without substitute slag additives.

Increased requirements are also imposed on fine-grained aggregates, since they are also capable of influencing the strength characteristics of expanded clay concrete. This is the usual quarry sand, but certainly sifted and washed. To reduce the density of the screed and increase its thermal insulation properties, it is better to choose a larger fraction of sand.

Since the finished solution does not have sufficient mobility (its characteristics correspond to the lowest class P1), plasticizing additives are introduced into it to improve the workability of the mixture. It is possible to use air-entraining modifiers such as SDO, which additionally porosize the cement matrix. But it is cheaper and easier to independently pour liquid soap into the concrete mixer at the rate of 50-100 ml per bucket of PC.

Proportions for different brands

To determine the scale of work, you will need to measure the area of ​​the room and calculate the height of the future layer of expanded clay concrete. The fill volume is the amount of clay aggregate in cubic meters, from which you should build on in further calculations. "Warm" monolith can be obtained in different densities - from 1000 to 1700 kg / m3 (although it is better to use the most durable coatings for the floor), in accordance with this, the proportions for the screed will also change.

With good moistening of expanded clay for such proportions, 140-200 liters of water per cubic meter of solution is enough. If soaking is not effective enough, the amount of liquid can be increased to 300 l / m3.

Traditionally, builders use a simplified ratio to obtain lightweight aggregate concrete of grade M100 - the "warm" screed that is optimal for building on their own. To do this, take 1 part of the cement:

• 3 hours of sand;
• 4 hours of expanded expanded clay;
• 1 h of water.

With such proportions, you can even purchase sand cement, where bulk materials just go in a 1: 3 ratio. If the screed is needed stronger, they simply choose a different cooking recipe for it:

When working with cement of a higher grade M500 and screed devices in household premises with operational loads not higher than average, it is recommended to use the following ratio of components per cube of expanded clay:

• 295 kg of cement;
• 1186 kg of coarse sand;
• 206 liters of water.

Lightweight screeds are prepared from expanded clay with a density of 200-300 kg / m3 without the addition of sand. Here you need to make a solution with the following ratio:

• 720-1080 kg of expanded clay granules;
• 250-375 kg of cement;
• 100-225 liters of water.

Expanded clay is poured into the container first. Before this, the granules must be soaked in water so that they are saturated with moisture and then do not pull it out of the concrete. After adding a little more liquid, sand cement is poured into the trough or drum of the mixer, thoroughly mixing the solution. With correctly selected proportions of expanded clay concrete, all granules during the manufacturing process should become the same gray color - without brown spots.

If the mixture does not seem fluid enough, you can add a little more water to it. If there is an excess of moisture, dry components should not be poured, since this will not allow them to be stirred to homogeneity and will worsen the quality of expanded clay concrete, violating the ratio of cement. In this case, it is better to let it brew a little, and then stir again.

Cooking should be done quickly and without delay. As soon as the granules are completely covered with cement slurry, the composition must be immediately poured onto the base, leveling it along the established beacons. A mortar with expanded clay aggregate sets faster than ordinary concrete, but after a week it will be possible to move freely on such a floor. The final set of strength occurs within 28 days.

Features of working with expanded clay concrete

Before pouring, it is imperative to lay waterproofing on the floor or coat it and the lower part of the walls with bituminous mastic. Otherwise, moisture will be absorbed into the base, preventing the cement from gaining the required strength. Such a fill will turn out to be non-monolithic and very fragile - it will creep under load and dust. Also, around the perimeter of the room, it is imperative to secure a damper tape to compensate for thermal expansion. At the end of the work, the expanded clay concrete screed will require additional protection against moisture evaporation. To do this, cover it on top with a film, which can be removed in a couple of days.

The finished layer of "warm" concrete needs final leveling - preferably with preliminary grinding. From above, it is poured with ordinary sand cement mortar with a thickness of no more than 30 mm (without adding gravel). This is enough to hide irregularities, but not deteriorate the thermal insulation characteristics of the rough base. The finishing fill is performed along the beacons, carefully leveling the mixture with the rule. The slats are carefully removed the next day, and the remaining traces are sealed with fresh composition.

A semi-dry screed is another option for warming and leveling the floor using expanded clay, which allows you to process small areas one after another. In this case, dry granules of expanded clay are poured onto the prepared base with installed beacons - to such a height that 20 mm of the beacon profile remain uncovered. From above they are spilled with liquid cement mortar (milk) and tamped, gluing the expanded clay grains together. After a day or two, the surface is poured with a finishing screed - the preparation of concrete for it is no different from the already discussed "wet" method.

Expanded clay has excellent heat-insulating properties. It is actively used in the process of erecting foundations, building floors between floors, and even for the construction of attics. Only 10 cm of a layer of expanded clay crushed stone is warmer than 30 cm of wood and 100 cm of a brick wall. And expanded clay is ideal for underfloor heating. It is only important to use this unique material in a screed technologically competently - and there are three such options.

First, we bring to your attention a couple of introductory videos:

Advantages and disadvantages of expanded clay

Expanded clay is obtained using a special technology: special types of clay are fired at high temperatures. Small granules with a porous structure are obtained, which have a number of important advantages:

• Environmental friendliness
• Durability
• Thermal insulation
• Soundproofing
• Strength

And at the same time, expanded clay is quite affordable for everyone. Not happy with only one drawback - instability to moisture, and this already implies some restrictions in use.

Types of expanded clay backfill for screed

The density of expanded clay, which the market offers today, ranges today from 250 to 600 kg / m3, according to which the following types are distinguished:

1. Expanded clay crushed stone. This material is 10-14 mm in size and is more often used for making concrete.
2. Expanded clay gravel. This one is used for the installation of durable and lightweight floors, and has three categories: 5-10 mm, 10-20 mm and 20-40 mm.
3. Expanded clay sand. It is used for thin screeds, the size does not exceed 5 mm.

The choice of the type of fraction depends on the exact room in which you will make a screed with expanded clay, and by what technology.

We use expanded clay in a screed: 3 options

So, the standard recipe for a living room is a package of 50 kg per 60 kg of cement-sand mixture. But for industrial premises, where the load on the floor is more significant, different proportions are needed. Let's just say that expanded clay will not withstand a lot of pressure, and therefore is not suitable for warehouses with equipment.

Semi-dry screed with expanded clay: we insulate and raise the floor

A semi-dry screed with expanded clay is the only option in which there is no need for thorough preparation of the base. You just need to sweep and remove debris from the cracks. And so that there is no moisture, of course.

If there are wires under the floor, we hide them in a corrugation and press them well to the base. After cleaning, we cover everything with a solid PVC film or a special vapor barrier, for example, glassine for a wooden floor. Its task is to protect expanded clay from the effects of moisture from below, which is often formed on the interfloor floor. It is necessary to lay the film with an overlap, securing it with tape.

Now mark the level of the new screed. It is better to do this with a professional laser level. We beat off the lines on the wall and repeat them with a regular pencil or marker. If there is no laser, use a regular rack and pinion level.

We now leave a gap of 10 cm along the walls, where we insert the thermal insulation material. Additionally, it will provide good sound insulation. As a last resort, use a standard edging tape one centimeter thick and ten wide. Now we pour out the expanded clay from the bags and distribute it over the entire surface of the floor as usual.

In the first case, you need to pour the expanded clay with cement milk in advance. Expanded clay granules are hygroscopic and absorb moisture quickly due to their porosity. Therefore, if you do not do a similar preparation, this water will be pulled dry granules from the screed, and it will shrink unevenly. But even with preliminary wetting, it cannot be guaranteed that the water from the screed will not go to the backfill even a little.

A semi-dry floor screed is used to level the base and serves as a foundation slab for the topcoat. You will learn more about the device of such a floor and the secrets of the correct technology from the material:.

In the second case, this no longer threatens, tk. even ordinary plastic wrap will easily prevent moisture from getting to the bedding. But then you need to be very careful so that the film does not break anywhere.

Concrete screed with expanded clay, or expanded clay concrete

Before installing a concrete screed with expanded clay, i.e. expanded clay concrete, diagnose the basis. Just determine how uneven the floor is:

• Step 1. To do this, take an ordinary two-meter level in your hands, put points in the corners of the room, and find the centers of the joining lines of the walls and floor.
• Step 2. After that, divide the space into segments and check each section separately.

Based on the detected curvature of the floor, calculate how thick the new screed will be. Now it is important to make the solution correctly: we pour the granules into a large metal bath and pour enough water so that it is exactly half of the palm above the level of expanded clay. Some of the water will be absorbed, because the granules have a porous structure. Just mix the expanded clay with water until the mixture changes its shade. After that we add sand and cement.

It is also necessary to distribute expanded clay concrete between lighthouses. We level it well, and let it dry for two days. Then you can make another such layer or start finishing the floor.

For serious irregularities, ready-made solutions from the Vetonit company are also suitable - these are mixtures where expanded clay crushed stone is held on a cement-containing binder. Such a screed is able to smooth out any irregularities well, even those that reach 30 cm. By the way, such a screed dries faster than ordinary concrete.

Dry screed with expanded clay: modern technologies

Here are the main advantages of a dry screed with expanded clay:

1. Sturdy and completely flat subfloor that can withstand a load of 500 kg per square meter.
2. Hypoallergenic and lack of any harmful volatile substances in the air.
3. No cracks, no breaks, no chips, as with a conventional screed.
4. Ready for use immediately after installation.
5. Good soundproofing.
6. The floor is so warm that no additional systems are needed.
7. The shortest terms of work: even a fairly spacious room, one working team will lay out in just 3 hours.

Absolutely any coating can be mounted on the finished surface: parquet, porcelain stoneware, laminate or even tile. It is impossible only a water heat-insulated floor - only electric, and preferably a film in general. Such a dry screed with expanded clay is especially valuable in that it practically does not create additional load on the floor slab.

But ordering the execution of such a screed according to the announcement is rather risky - violations of technology will lead to the fact that the floor will "flop" when walking, and certainly will not differ in evenness. So, you should be alerted if the workers you hire:

• Expanded clay is used not in coarse fraction, but crushed.
• Instead of sheets of GVLV, they put those that are not intended for such work. For example, plasterboard.
• The gap between the wall and the sheets is too large.
• The folds at the edges of the abutment to the wall were not cut off.
• The sheets are fastened together not with glue, but with polyurethane foam.

This is how it happens that fairly high-quality materials are used unprofessionally, and such a screed subsequently bends even under a person. This is where the myths appear that only "wet" or semi-dry screeds are the only normal method to make an even and durable floor.

But you must agree that any success depends on how you approach business, and this is especially important in the construction industry.

Today, there is a large selection of modern materials in the implementation; in terms of their heat-saving performance, they meet the requirements of the current regulatory enactments. Expanded clay is not considered a new insulation; it has been used in construction for many decades.

1. This is the only insulation that can be placed on any base, including the ground. Do not put mineral wool or foam on the ground, this is strictly prohibited by the recommended technologies.
2. Expanded clay has the highest values ​​of physical strength. According to these indicators, it is much ahead of the widely used modern counterparts.
3. Environmental friendliness. Expanded clay is made from clay, does not emit any harmful chemical compounds into the air.
4. Non-flammability. It is approved for use by fire organizations without restrictions, it is allowed to be used as an open fire barrier.
5. Low cost. This is the cheapest insulation for universal use. It is used to insulate floors, ceilings and walls. It can be used in both residential and industrial or commercial buildings.

Depending on the size, expanded clay is divided into several fractions: sand (5–10 mm), crushed stone (10–20 mm) and gravel (20–40 mm). Expanded clay is obtained after firing low-melting intumescent clay grades, has a porous structure. The production technology allows the use of various special additives to improve performance. According to the characteristics of the bulk density, the material is divided into ten grades, designated by numbers from 250 to 800, indicating the weight of one cubic meter in kilograms.

The technology consists of several stages, each with its own characteristics and requirements of building codes and regulations. A floor screed with expanded clay is made of three layers: dry expanded clay, concrete mixture with insulation and a clean cement-sand screed. How to make insulation?

Important. To increase the efficiency of insulation, it is recommended to use several fractions of expanded clay at the same time. Small fractions will fill the air chambers and make the insulation denser and more resistant to stress.

Step 2. Prepare the base surface. If the insulation is to be used on the ground, then it must be leveled, a layer of crushed stone with a thickness of ≈ 5 cm should be poured, a layer of sand approximately 5 cm thick on top. The base must be thoroughly tamped.

If the insulation is used on a concrete base, then you need to remove the old coatings and debris. If large cracks are found, they must be sealed with any solutions.

Expanded clay allows you to insulate inclined surfaces, leveling the surface is done with insulation. This greatly speeds up and reduces the cost of construction work.

Step 3. Make waterproofing. One of the disadvantages of expanded clay is a significant decrease in heat-saving characteristics with an increase in relative humidity. The material is porous and absorbs water. The presence of water in the granules significantly increases the thermal conductivity coefficient. But not all thermal insulation materials can be used for waterproofing. Granular insulation, creates significant point forces on waterproofing materials. In these places, there are great risks of damage to film waterproofing materials: plastic film, nonwovens, etc.

roll waterproofing

If the base is concrete, then it must be insulated with mastics based on modified bitumen. The brands do not really matter, they all perfectly fulfill their tasks. Professional builders recommend applying at least two layers of mastic, carefully treating the most problematic areas. Expanded clay can be poured only after the mastic is completely dry, the specific time depends on the brand.

It is a little more difficult to do waterproofing on the ground. The finishing base is compacted sand, it can give uneven shrinkage under load. The most durable materials should be used as waterproofing materials on such bases. Roofing material with two layers of coating with modified bitumen is considered optimal.

Step 4. Pour a layer of expanded clay. Marks should be made around the perimeter of the room using a hydro level or a laser level. One mark is the height of expanded clay, the second is the height of the cement screed and the third is the height of the final flooring. The thickness of the layers must meet the requirements of the design documentation or self-made calculations. Using a long strip (rule), level the surface of the poured insulation.

Practical advice. Walking on the surface of expanded clay during other construction work is very inconvenient, it falls through underfoot. In order to facilitate further work and improve the bearing performance of the screed, it is recommended to put a reinforcing mesh on dry expanded clay. The specific parameters of the mesh are selected taking into account the possible maximum loads.

Check the position of the insulation, if necessary, level out large elevations or fill in the grooves.

Step 5. Prepare the sub-screed mortar. It must be done from two or three parts of expanded clay and one part of a cement-concrete mixture of the usual composition. This layer serves to fix the coating and additionally insulates the floor. The thickness of this layer is within 5–8 centimeters.

The screed laying technology has its own characteristics

1. For lighthouses, you need to take special metal elements with a wide base, strips should be purchased at hardware stores. If this is not possible, then you will have to make them yourself from slats or boards. The length of the lighthouses is approximately 1.5–2.0 meters, the slats should be as even as possible. Knock down the boards with the letter T, the base must be put on expanded clay.
2. Do not try to make the fill perfectly even, the slats are loose, it is impossible to keep the rule at a constant height. The final leveling is done with a second layer with a thickness of ≈ 2 cm. If the volume of the solution is large, then to walk on expanded clay, put several boards, make a temporary path.
3. Try to take a long rule, work as far away from the lighthouses as possible, this will help reduce their wobbling.
4. Along the perimeter of the room between the wall and the screed, special gaskets are used to dampen the thermal expansion of the screed.

The first lighthouse should be done at a distance of 30 centimeters from the wall, the distance between the next depends on the length of the rule, they should be located about thirty centimeters closer.

You can additionally fix the lighthouses with plaster or cement mortars. This will make the work somewhat easier, but they should still be done very carefully. Install the lighthouses below the level, if there is a laser device - great. It is very convenient to work with it, the performance of all construction works is much faster and their quality is increased.

Do not rely too much on floor insulation with a solution made using expanded clay. During preparation, the granules of the insulation are filled with water, the conductivity of heat increases significantly, the effectiveness of such a heater is quite low. Use the prepared solution only for fixing the top layer. This method is used to strengthen the top layer of insulation and facilitate the final leveling of the screed.

After pouring, you need to give time for the solution to harden. If for ordinary screeds, a day is enough to continue to carry out work on the installation of floor coverings, then in the option of using expanded clay, the waiting time increases to at least seven days. The fact is that the cement slurry does not have a continuous support area, and individual expanded clay granules are very mobile.

Simplified technology of floor insulation with expanded clay under the screed

Among the advantages of expanded clay insulation, one more should be called - the ability to hide all engineering communications in the insulation. This increases the safety of operation, minimizes the likelihood of accidents due to mechanical damage or violation of the recommended operating conditions. In addition, it does not restrict access to pipelines or electrical cables, if necessary.

The main difference is that this method does not require making a leveling finish screed. Expanded clay is mixed with a cement-sand mortar in a ratio of 1: 5, this mass is simultaneously used for insulation and a screed.

Advantages - the work is accelerated several times, the presence of waterproofing is not critical. Expanded clay granules are protected from the penetration of additional moisture by a cement composition. Another plus - the insulation is not afraid of cyclic static and dynamic loads. To increase the bearing capacity, it can be poured in two layers, and a reinforcing mesh can be laid between them.

Disadvantages - reduced properties of thermal insulation, the need to increase the minimum thickness of the insulation and an increase in loads on the supporting bases. The method is recommended to be used during floor insulation on the ground.

expanded clay

To increase the strength of the expanded clay screed, it is recommended to wet it with water twice a day. This must be done carefully, do not fill with water, do not allow dry expanded clay to get wet. Watering significantly improves the physical performance of the screed, the chemical reactions of the cement slurry proceed in a favorable mode. You need to water the screed for two to three days, the exact time depends on the weather. At high temperatures, the number of soaks increases; complete drying of the top layer of the screed must not be allowed.

If the operating conditions of the building require an increased height of the expanded clay insulation layer, then it can be stacked in bags. Plastic bags increase the stability of the position of the granules, expanded clay does not crumble under the feet of the master, there is no need to use special additional devices and devices. For the final leveling of the surface of the filling, a layer of fine fractions with a thickness of 2-3 cm is added from above. This technology allows to reduce the time by 30%.

If possible, do not use expanded clay floor insulation technologies using cement milk. The strength of the base will increase, but the heat saving effect will be significantly reduced. There are many other building techniques for increasing the load-bearing capacity without compromising the thermal performance of the floor.

Warming with expanded clay is very beneficial to do in outbuildings or garages. Especially if the construction site is uneven, and it is impossible to engage in excavation preparatory work for various reasons. Expanded clay will independently even out the differences in the base in height up to ten centimeters, an increase in the amount of material does not have a noticeable effect on the change in the initial estimated cost of the object.

The tangible effect of floor insulation with expanded clay can be achieved with a layer of insulation of at least 15 centimeters. This must be borne in mind when choosing the type of base for the screed. Not all rooms allow flooring due to such a significant reduction in the height of buildings.

The more airtight the top waterproofing, the higher the thermal insulation performance. It increases due to the absence of air convection, waterproofing serves as a reliable obstacle to the movement of warm and cold air masses. The optimal method for the upper waterproofing of the floor screed is ordinary plastic wrap.

Video - Insulation of the floor with expanded clay under the screed

The floor screed can be done using various materials. It all depends on the purpose, as well as the desired result. Under certain circumstances, a semi-dry floor screed can be arranged under a "warm floor" or under any floor covering. Cases of installation of a "rough" floor on expanded clay, which is famous for its main advantages, are not uncommon. In addition, it is important to observe the technology itself so that negative consequences do not appear.

Pros and cons of expanded clay

As for the lighthouses, their number, first of all, will depend on the rule used, its length. With its length of one and a half meters, the above room will require about five lighthouses throughout the entire area. The length of such beacons is chosen over the entire width of the room - three meters.

The choice of the expanded clay itself is focused on granules, or rather their fraction. To calculate everything correctly and independently, it is enough to open the calculation calculator, which can be found on the Internet. In this case, it will not be superfluous to ask for help from familiar builders. They will tell you the exact amount of material to purchase. It is worth noting that the materials for underfloor heating screed are no different in quantity.

Preparatory activities

The same preparation is carried out both for the usual execution of the screed and for the semi-dry one. That is, it makes no difference whether the floor screed is dry or semi-dry will be necessary for the flooring. It is very important here to level the foundations where the work will be carried out. All existing cracks and pits, if possible, are eliminated with a cement mortar. Bulges can be knocked down. We must not forget about the waterproofing layer, which can become a regular plastic film. The better the material is chosen, the better qualities it can show during operation.

After that, sand is poured, acting as a pillow under expanded clay. Usually its layer is 20-30 mm. The pillow should also be leveled and leveled using a rule of thumb. As for tamping the sand, it will be enough just to walk along the entire plane. In this case, the weight of a person will be enough.

The choice of expanded clay is carried out depending on the fraction (small, medium and large fraction). It falls asleep throughout the room, starting from the far corner. After filling the required layer, it should be leveled. On the top of the expanded clay, beacons are installed, which serve as the main one for the sub-floor level.

Profiles are used as beacons, which are mounted on the base using a cement-sand mortar. Subsequently, the screed is poured, somewhat stepping on the lighthouses, and they simply "hide" into the base of the subfloor.

Semi-dry screed

When expanded clay is filled up, you can choose two options for further actions:

Not everyone knows how to make cement jelly. For this, twice the amount of water is used than with the standard version of the screed. Depending on the result obtained, it should be considered whether it is necessary to add additional water or cement. In this form, after pouring expanded clay, it is necessary to let the layer brew and dry for at least a day. Only then can a semi-dry concrete floor screed be poured.

If the beacons are removable, then they are pulled out only after a few days. The resulting grooves are sealed with a solution, carefully tamped and sanded until a uniform layer is obtained.

Expanded clay with solution

There is also such an option for performing a semi-dry screed, when the solution itself is mixed with expanded clay granules. This process takes much less time than in the previous case.

Expanded clay is poured into the container, which is prepared in advance, which is filled with water in the required amount. Mixing is carried out using a mixer. A ready-made dry mixture is poured into this, which must be thoroughly mixed until a homogeneous mass is obtained. You should be very careful with the amount of water. After all, it requires a small amount. Overkill will lead to the manifestation of negative qualities.

There should be no lumps when stirring, and the granules themselves should become wet and acquire a gray tint. The mixture becomes slightly thick, resembling sour cream in consistency.

The prepared base is poured with a ready-made solution to a thickness of 20-25 mm. But the thickness will depend on the evenness of the floor, as well as on the final result that is required for the flooring. The reduction in time occurs for the reason that there is no need to wait a day for the first layer, filled with cement milk, to dry and harden.

After the initial layer of the "pie", a second and subsequent one is carried out until the formation of a "rough" floor. During the work, we do not wait for the drying of the previous layers. The finishing layer is not only carefully rammed, but also leveled.

Semi-dry floor screed requires certain knowledge and experience in performing work. Even small nuances will avoid possible problems in the future during operation. Some of them:

• When placing the wires on the floor, under the future screed, they should be at least wrapped in polyethylene, and also attached to the base of the floor with tape.
• To avoid cracks in the poured concrete solution, it is best to add a plasticizer to it. It will be enough only for the finishing layer of a semi-dry screed.
• Not only polyethylene film, but also bitumen mastic, waterproofing, etc. can serve as a waterproofing of the floor.
• After pouring the screed follows. The main activity is periodic wetting using a spray bottle.
• Drying time of the screed is about a month. The longer it stands without external pressure, the more strength it can gain in the end. Much will also depend on the flooring used.
• Beacons can be metal slats or special profiles called "beacons".

Compliance with the screed technology, whatever it is, will allow you to get a flat surface of the subfloor, on which you can immediately carry out the flooring.

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One of the most important construction operations when performing repair work in a room is the preparation of the floor surface and its layout. The need to level the floor surface inevitably arises in old buildings and modern buildings, the floor in which does not differ in perfect flatness. To accomplish this task, it is often used with expanded clay, which is the most affordable way to level the base. It is not difficult to plan the surface yourself, having decided on a method of work that depends on the condition of the floor.

Expanded clay for screed - material advantages and expediency of use

Expanded clay granules are a building material made from high-temperature fired clay. Particles of granulated expanded clay have a spherical or oval configuration, characterized by a porous structure.

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

The material for making the screed has a set of advantages, which is due to the properties of expanded clay granules:

• resistance to temperature extremes. They retain their properties when cooled and heated, and can be used in unheated rooms;
• the ability to soundproof the room by absorbing external noise. Due to the cellular structure of granules, expanded clay filler effectively absorbs extraneous sounds;
• increased thermal insulation characteristics. The use of granular insulation allows you to reduce financial costs during the heating period;
• environmental friendliness. The heat insulator is made from environmentally friendly and harmless raw materials, does not adversely affect the health of others;
• long service life. Granules retain their performance and porous structure for decades, providing effective thermal insulation;
• increased strength characteristics. Expanded clay floor in terms of safety margin is not inferior to the traditional one - based on cement, while providing moisture and air exchange.

Expanded clay screed combines increased strength and low weight. This allows you to form a reliable base, reducing the load on the floor slabs.

The material combines the soundproof and thermal insulation properties of wood with the durability and strength of natural stone. This is due to its widespread use for solving various construction problems, including for the formation of floor surfaces.

Screed floor with expanded clay - one of the simplest options for leveling the floor

Certain situations arise when it is advisable to use the only possible option - expanded clay for screed:

• with a significant difference in height in the room, amounting to 100–150 mm. The use of concrete in this situation will significantly increase the load on the floor slabs;
• if necessary, reduce the weight of the array. This is true for floors made of wooden beams that only accept limited loads;
• if there is a small amount of cement and a desire to save money on the use of heavy building materials;
• in a number of technically justified cases related to the equipment of various heating systems or the laying of utility lines in the floor;
• when planning floor areas with difficult terrain. For different layer thicknesses, it is important to ensure a low level of shrinkage, for example for laying parquet.

Many developers who preferred expanded clay were convinced of the advantages of the material, the convenience of its use.

Screed with expanded clay - possible options

When planning the bases, the following methods are used to form the floor surface using expanded clay granules:

• prepare a cement-sand mortar, which is poured onto a claydite pillow. The technology provides for the preliminary distribution of the material over the surface. Then pouring with cement milk is performed, which holds the bedding together. After pouring the finished composition based on cement and sand, it is stretched by the rule and formed towards the exit;

Expanded clay floor screed is very resistant to frost and extreme heat, therefore it is used in rooms with any conditions

• mix the granules with a sand-cement mixture, add water and fill the floor. This method is distinguished by its simplicity of execution, it allows to form an even base in a limited time. All ingredients are mixed in the required proportions with the addition of water to the required consistency. Completes the process of pouring and uniform distribution on the floor;
• the dry method involves the preparation of a mixture of expanded clay granules with sifted sand. The process is characterized by an increased rate of laying, allows you to form an even base on increased areas. Dry filling technology allows you to prepare the floor without the use of cement mortar and avoid temporary losses associated with the drying out of the mortar.

Any of the selected methods, performed in accordance with technological recommendations, will allow the base to be operated for a long time without major repairs, will help create a solid foundation for the finishing coating, and will also ensure the safety of the engineering communications under the expanded clay.

Screed floor with expanded clay - preparatory stage

The quality of the formed base depends on the correct preparation of the floor surface. For any method of floor planning, a number of steps must be taken to prepare the base.

Sequencing:

After completing the preparatory work, proceed with the activities according to the chosen method of work.

Screed on expanded clay - how to mark and install beacons

To form an even coating located at the same level, it is necessary to responsibly approach the marking and installation of guides (beacons).

To start marking work, you need to prepare:

• building level;
• pencil or marker.

The first stage is floor marking and installation of beacons for floor screed