Floor insulation with expanded clay. Which expanded clay should I choose and what thickness should I lay the layer?

For passionate supporters of the use of environmentally friendly materials in construction, the question of whether expanded clay can be used for floor insulation will probably seem strange - of course, yes! For its production, absolutely natural materials are used - clay and shale rocks, which are sintered and granulated in a rotating cylindrical kiln at high temperature. The result is granules of different sizes.

But expanded clay is good not only for its high environmental friendliness. It should also be noted its low cost in comparison with other insulating materials, as well as the ease and speed of its application, because this does not require any special equipment.

More about expanded clay

The word "expanded clay" has Greek roots and is translated as "burnt clay." This material is extremely light, has a cellular porous structure, and its granules are round in shape. During the firing process, low-melting clays, to which peat, sawdust and diesel fuel have been added, swell. Expanded clay is often used in construction as a filler in concrete in cases where it needs to be made lighter.

The thermal insulation properties of expanded clay are affected by:

• granule size;
• granule strength;
• density of the material.

Based on bulk density (or volumetric weight), there are 10 grades of expanded clay (from 250 to 800). The brand number hides the bulk weight of the material, expressed in kilograms per cubic meter. For example, a cubic meter of expanded clay grade 250 weighs exactly that much in kilograms.

The greater the porosity of the material, the lower its density and the higher its thermal insulation properties, which is very important when choosing which expanded clay is best for floor insulation.

Different bulk densities are obtained with different methods and modes of processing the feedstock. Bulk density is determined by filling special measuring vessels. Typically, the largest fraction has the lowest volumetric weight.

The principle of operation of insulation

Many people know that the most effective thermal insulation material is air. Along with it there is only inert gas, which almost does not react to the environment. It is this gas that is used to fill the glass unit chamber. However, you cannot use it for building structures (floor, walls, ceiling), since absolute tightness is required.

Almost all materials for thermal insulation have a porous structure. Due to this, there is air in the pores, which inhibits heat loss. There is a certain pattern: a less dense material has better thermal insulation properties than a dense one. The lower the density, the better the insulation.

All insulation materials can be divided into several types:

• roll;
• slab;
• bulk;
• sprayable.

The most budget-friendly is the sprayed type of insulation, which includes expanded clay. The fact is that this type of material has almost the lowest thermal protection indicators. But it can insulate the structure. Why do you need thermal insulation at all? Look at the photo to find out.

Insulation work solves at least 4 problems:

1. Provides a reduction in budget waste on heating the house.
2. They protect the structure from condensation, which serves as a source of fungus and mold.
3. They create comfort, warmth and coziness in the house.
4. Gives the room soundproofing properties.

If you do not insulate your house, its operation will bring you many problems. What can we say about expanded clay as an insulation material?

Varieties of expanded clay

Expanded clay sand

It is formed after firing clay residues or by grinding large fractions of expanded clay. The particle sizes here are no more than 5 mm. This sand, together with large fractions, is used for insulating interior partitions or when floor insulation with expanded clay concrete is required. It also serves as a filler for cement mortar.

Expanded clay gravel

It consists of rounded grains 5-40 mm in size with a porous structure, which are obtained in pyrogenic furnaces when superfusible clay is expanded. It is fire-resistant, frost-resistant and water-resistant material.

Expanded clay crushed stone

It is angular, has no definite shape, and is similar in size to gravel. It is obtained by crushing large pieces of expanded clay, and is used together with other types to produce lightweight concrete if the concrete floor is to be insulated with expanded clay.

Experts recommend using a mixture of different fractions of expanded clay to insulate the floor. So, for residential premises it is recommended to mix 10 mm granules with smaller ones (5 mm) or even with expanded clay sand.

Floor screed with expanded clay: secrets of creating a warm and durable base in detail, with photos

Among the disadvantages, it should be noted the poor moisture resistance when using the dry screed method, so in some cases it is better not to use expanded clay. The material will not be damaged directly, but moisture will linger under the concrete. This will subsequently lead to increased humidity in the room. This factor is favorable for the development of fungi and mold. The disadvantages of the material also include the fact that for insulation you will need to make a thick screed. A layer less than 10 cm will be ineffective.

Expanded clay is a very light material and therefore does not weigh down the screed and does not place additional load on the foundation

Expanded clay concrete screed outperforms other fillers in many ways. In addition to the maximum level of heat and noise insulation, it has good breathability and is durable. The material is suitable for any floor covering. The maximum effect from all of the listed positive qualities can be achieved only if all the requirements of the expanded clay laying technology are met.

Various materials are used to insulate floors, walls and ceilings of buildings. In addition to expanded clay, the most popular materials also include polystyrene foam, polystyrene foam and mineral wool. They are characterized by such qualities as lightness, high thermal insulation and low price. However, due to their versatility, expanded clay or mineral wool are most often used. Floor insulation with these materials is most effective.

Expanded clay, as an environmentally friendly material, does not pose a threat to health and lasts for several decades. It is inexpensive, multifunctional and resistant to fire, moisture and rodents. However, its use requires a number of preparatory works, so it is not suitable for creating “warm floors”.

Expanded clay has high thermal insulation properties and is cheaper than other materials

Insulating walls with expanded clay outside the house is a rather labor-intensive and inconvenient process. This is where expanded clay is inferior to mineral wool, which is suitable for insulating facades, roofs and pipes in hard-to-reach places. It is easy to cut out the required shape using a knife.

It is impossible to say unequivocally which material is better, much less make a categorical choice in favor of one of them. The choice of insulation should be based on the specific construction conditions and material capabilities. Most often, experienced builders combine mineral wool with expanded clay, which has a positive effect on the cost of work and increases the degree of thermal insulation. Both insulation materials are distinguished by their simple installation process and low cost, giving excellent results.

Insulating walls with expanded clay gives excellent results for the entire life of the building

For expanded clay screeds, various types of fractions are used. The modern construction market offers materials with different levels of density. The weight of a cube of expanded clay ranges from 260 to 600 kg/m³. The specific gravity of expanded clay is the weight of a cube of material. It depends on the grain size: the larger the grain, the lower the specific gravity. It is the mass of 1 m³ of expanded clay and its density that underlie the classification of the material given below:

The table will help to clearly demonstrate the specific and volumetric gravity of expanded clay, depending on the type and fraction:

In accordance with the table, the approximate weight of 1 m3 of expanded clay with a fraction of 10-20 is 350-400 kg.

The specific gravity also depends on the brand of density. According to existing GOST, the higher the density of expanded clay, the greater the weight of the material.

It is impossible to accurately determine the specific gravity of expanded clay, but the average value is quite easy to establish. The average value is 400 kg/m³ (0.4 g/cm³). Moreover, each faction has its own specific indicator. For example, expanded clay 10-20 in bags weighs approximately 16.8 kg.

It should be noted that loose clay granules are widely used not only in construction, but also in public utilities and agriculture. Therefore, the price range for this material is quite wide and ranges from 1000 to 2000 rubles per cubic meter.

Expanded clay granules have a porous structure, so they are good for use for dry screed

Expanded clay producers also dictate the pricing policy on the market. When setting prices, they are guided by the following criteria:

Enterprises selling expanded clay also take other factors into account when setting prices. For example, packaging, size of granules and their porosity. The first criterion includes a list of additional costs for purchasing additional equipment and hiring workers to dispense, weigh and package the material.

The size and porosity of the material determine such qualities of expanded clay as thermal insulation, strength, and moisture absorption. All these criteria respectively influence the formation of prices. For example, the size of the granules determines the price in inverse proportion: the finer the grain, the higher the cost. The price of small expanded clay in bags is much higher, since the material itself is much heavier compared to the weight of large fractions of expanded clay of the same volume.

Expanded clay is produced in fractions of different sizes, suitable for any type of work

Sales agents on the construction market offer the purchase of expanded clay wholesale and retail, packaged or in bulk. Buying material by weight or per cubic meter is much more profitable, since when packaging, labor costs and the cost of packaging influence the formation of the price. If the question is about purchasing expanded clay for floor insulation, and not for backfilling an area as a decorative element in landscape design, then it is enough to purchase just a couple of cubes of material.

Packaged expanded clay is of higher quality, as it undergoes special cleaning. In addition, the packaging is more convenient to transport and protects the material from moisture, maintaining its quality characteristics.

When buying expanded clay, you should take into account another important factor - seasonality. Usually, after the end of the construction season, the price of the material drops by about a quarter. Thus, granular building materials can be purchased much cheaper in winter.

If it is important to purchase high-quality, clean, hard and certified material, you should give preference to expanded clay in packaging. Since it has been certified, it will be free of impurities, debris and foreign matter. The strength of the granules can be checked by simple compression, and porosity is determined by breaking the grains.

If you need to purchase purified, high-quality material, you should give preference to expanded clay in bags

Floor screed carried out using the dry method is more advantageous compared to other technologies. First of all, the cost savings lies in the absence of the need to involve professionals, because most dry screeds can be made with your own hands.

When it comes to expanded clay, the overall cost is also affected by the method of its use. For dry screed, material of different fractions is taken - and its price can be low. While the pouring method requires fine-grained expanded clay, which costs an order of magnitude more.

Fine-fraction expanded clay is best suited for self-leveling screed

The best price for products can be found from the direct manufacturers of the material. Intermediaries, as a rule, set a markup of 15 to 30%, which includes the costs of delivery and storage. Therefore, to purchase large volumes, it is better to spend time on the road and bring expanded clay from the manufacturing plant yourself.

If we are talking about small quantities of goods, then it is better to refuse pickup and buy the material in specialized stores with delivery. The seller guarantees timely transportation, safety and quality of products. In any case, to avoid unnecessary costs, you should correctly calculate the required amount of material.

When choosing which fraction of expanded clay is needed for floor screed, they are guided by the room in which the material is planned to be used. The choice also depends on the technology used to backfill. According to the traditional method, which involves subsequent pouring of concrete, the size of the material does not matter much. Any type will do, including fine-grained expanded clay.

For a better quality screed, use expanded clay of different fractions, since this gives the required backfill density

At the same time, the opinion regarding the choice of a 0.5 mm fraction with a minimum weight for the base of expanded clay is erroneous. After all, such a filler has a higher density, so it fills the space better, thereby making the screed layer heavier.

Experienced builders recommend using expanded clay for screeding different fractions - from 5 mm to 20 mm in appropriate proportions. The recommendation is based on the fact that when laying a layer of expanded clay, grains of different sizes fit well together. This feature has a positive effect on the further use of the floor, which will not shrink or deform.

Expanded clay is a very ergonomic and economical material. Its use reduces financial costs, minimizes loads on concrete floors and increases the level of thermal conductivity. In order for the result to be as effective as possible, it is necessary to accurately calculate the required amount of expanded clay for the job.

To obtain a high-quality screed, it is necessary to comply with the proportions and installation technology

Builders use traditional methods when calculating how much expanded clay is needed for floor screed. If the layer thickness is 1 cm, then 0.01 m³ of material will be needed per 1 m². The weight of a cube of expanded clay is generally not taken into account, since the density of expanded clay calculated in kg/m3 varies for different types of material. Therefore, for convenience, sales are carried out in liters, based on calculations: for 1 m² of screed 1 cm thick you will need 10 liters.

To accurately calculate the consumption of expanded clay, you should measure the thickness of the insulating layer. In dwellings located on the lower floors or above unheated rooms, the thickness of the screed made of this material should be at least 10 cm. In order to maximize thermal insulation in residential premises, expanded clay is laid in a layer averaging 4 cm.

Based on the calculations given above, we come to the conclusion that to install a screed in a standard apartment you will need at least 0.04 m³ (or 40 liters per m²) of material. As a result of multiplying this indicator by the size of the room area, you get the total volume of expanded clay required for the screed.

The required amount of material must be calculated before starting construction work.

For example, you should calculate how much expanded clay is needed to insulate a floor with a layer thickness of 4 cm in a room of 15 m². The calculation will look like this:

15 m² * 0.04 m³ = 0.6 m³ (in cubic meters) or 15 m² * 40 l = 600 l (in liters).

The equivalent is 16 bags of 50 liters each. That is, one bag of expanded clay is consumed per 1 m² of screed. You can calculate exactly how much expanded clay you need for floor insulation using a special online calculator.

This material has been used as a reliable insulation material for quite some time. The heat-insulating effect of expanded clay granules is ensured by their porous structure.

Expanded clay ceiling insulation scheme

Expanded clay grains are similar in structure to expanded polystyrene. But there is also a significant difference: expanded polystyrene is made from polymers and is used mainly for wall decoration. Expanded clay is a natural material, the raw material for which is organic clay.

Due to the high degree of thermal insulation, the use of expanded clay for insulating floors, walls, ceilings and load-bearing structures is very effective. The material is often used for attic insulation due to its increased fire resistance (compared to expanded polystyrene). This advantage of the material allows its use in fire-hazardous objects: in a bathhouse, on the roof and on wooden floors.

However, using expanded clay on a horizontal base is more convenient than on flat or vertical surfaces, since it is a bulk material. To level and insulate the floor with expanded clay under the screed, it is enough to simply pour and level the material, but insulating the walls and ceiling will require more time and effort.

Scheme of floor screed with expanded clay and waterproofing in layers

Expanded clay is usually used to insulate the floors, ceilings and walls of wooden houses. Its use in brick and concrete buildings is very advisable. The most commonly used technology is to insulate the floor of a frame house with expanded clay. This is due to the fact that it is one of the most affordable, convenient and effective materials on the construction market.

Insulating the walls of a frame house with expanded clay is a labor-intensive and rather problematic process, so the use of this material for this task is less advisable. Although, due to its thermal insulation characteristics, expanded clay will well protect any wall - both brick and block. But the main condition for use is a three-layer structure, which will ensure the possibility of filling material between the rows.

In aerated concrete blocks, the distance from the inner to the front layer must be at least 10 cm. The material is filled in as the masonry is built. It is carefully compacted and filled with cement laitance. The consumption per 1 m3 of expanded clay binder M 300 will be 260-300 kg. It should be noted that in this case you will need about three times more water than cement.

Expanded clay for insulation is poured between the logs, after which all other work is carried out

Provided that the thickness of the side surfaces of the sandwich panels is correctly selected, it is possible to additionally insulate even frame walls with expanded clay, since during compaction the load on them increases significantly. To insulate the walls of a wooden house, it is necessary to prepare a thermal insulation layer of at least 20 cm. For this purpose, special canopies will have to be built for backfill.

Special expanded clay blocks used for the construction of walls have the necessary thermal insulation qualities. These are hollow structures containing expanded clay, sand and cement. Such buildings are warm in winter and cool in summer. This material is characterized by low strength, so it is suitable for the construction of one-story buildings and partitions between rooms.

Expanded clay blocks are a universal material that is used for the construction of insulated houses

Slotted blocks have good plasticity, which allows you to create different shapes. They are laid empty-sided down on a sand-cement mortar to save heat. Structural and thermal insulation blocks are a hollow material used for thermal insulation during the construction of walls. Depending on the size of expanded clay blocks, they are divided into wall, partition and facing.

Due to poor insulation, about 15% of the heat escapes through the ceiling, so during construction you need to take this factor into account and take care of insulating the ceiling or floor in the attic. For this purpose, mineral wool and polystyrene foam are often used, but expanded clay is deservedly considered the most popular material.

Insulation work begins with laying layers of vapor and waterproofing. A layer of vapor barrier film is attached to the finished ceiling. To do this, you can use self-adhesive roofing felt and foil, but if you don’t have enough money, a simple plastic film will do just fine. The technology is simple: a roll of the selected material is rolled out on the floor, marked and cut. The strips should be approximately 10 cm wider than the distance between the beams.

To ensure reliable thermal insulation, a layer of 10 cm is enough

If the ceiling area is large, it is advisable to lay the sheets with an overlap of 8-10 cm. The seams are taped with special tape or construction tape. When insulating the ceiling in a bathhouse with expanded clay, a vapor barrier should be provided for the beams and chimney pipe. The canvases are fixed above the expanded clay layer with masking tape or a construction stapler.

It is recommended to lay crushed clay over the waterproofing layer. Now you can begin laying the main insulation - material in a layer of 10 to 16 cm.

To insulate a roof with expanded clay, it is better to use a combined method, that is, take large and small granules. This will increase the density of the coating, and the level of subsidence of the granules will decrease, which will facilitate uniform filling of the material over the entire surface that needs to be insulated.

Expanded clay is most often used to insulate floors in different rooms. If you strictly follow the technology of using the material, you can achieve a positive effect even in a house with a very cold floor. It should also be noted that the floor bears the heaviest load, so a lot depends on what layer of expanded clay is needed to insulate the floor.

Dry backfilling of the floor with expanded clay is widely used for laying any type of flooring

Correct calculation of the insulation thickness will help avoid subsequent subsidence and surface deformation. It is also important to consider what expanded clay to use for floor screed. The most effective is the use of granules of different fractions. Then smaller grains will fall into the space formed by large grains, uniformly filling the entire surface.

Expanded clay screed plays a very important role. There are several technologies for its application. The screed provides fixation of the material and serves as the top waterproofing layer. Usually a two-level method of applying the solution is used. First, a layer of material is poured in order to fill empty spaces and displace air. Expanded clay under the screed is reliably protected from moisture and physical stress. The final screed is done to completely level the floor, which will be an ideal base for installing any type of floor covering.

Despite the fact that insulation with expanded clay (no matter the floor or ceiling of a house) is several times simpler than using the same polystyrene foam or mineral wool, the technology has a number of features. It is important to follow them, otherwise the insulation layer may become saturated with moisture.

For high-quality insulation with expanded clay, it is necessary to follow the backfill technology

There are many technologies for insulating wooden houses using this material. We have already figured out how to insulate the ceiling and walls, but the most common use of expanded clay is to insulate floors in a private home. There are many technologies and methods. This includes simple backfilling, pouring an expanded clay layer, and covering the material with a concrete screed.

In any case, first prepare the surface. To do this, dismantle the old coating, clean the surface of dirt, debris and dust. Next, they begin the process itself. The most popular method of insulating a wooden floor with expanded clay is to backfill it directly onto the ground, between the laid joists. Most often, this technology is used in the construction of country houses, but it is also acceptable in the arrangement of residential cottages.

The sequence of such work includes several stages:

Expanded clay is excellent for insulating wooden houses

This is the easiest way to insulate the floor in a wooden house from below with expanded clay. This method is also used to insulate the ceiling from the attic side.

Often in multi-storey buildings, the initial design assumes the presence of an open balcony or loggia, but most owners insulate the structure themselves by installing reliable heat-insulating double-glazed windows. Then the question arises about the need to insulate the floor in this room. There are a number of methods, in particular using expanded clay screed.

Considering how much expanded clay weighs, it is suitable as an insulating material for floors on balconies and loggias. The process itself is quite simple. First, a cement-sand mortar is mixed, then the entire surface of the concrete base is covered with an even layer of expanded clay 3-5 cm thick. After this, beacons are installed and, guided by them, the expanded clay layer is filled with concrete mortar.

Before insulating a balcony with expanded clay, it is necessary to carry out waterproofing

It is important that the cement mixture is thick to prevent light clay granules from floating, thereby compromising the thermal insulation effect. In addition, such a screed will be quite problematic to level.

It is important to take into account the fact that a conventional balcony slab is installed with a slight slope towards the outside. This is done so that rain and melt water flows freely from the balcony. Therefore, before insulating the floor with expanded clay, you need to take care of leveling the surface. The easiest way is with a concrete screed.

Quite often, expanded clay is used as a reliable material for thermal insulation of bathhouse floors. The required layer thickness is calculated taking into account the expected loads. Here they use technology using beacon filling. The simple method of falling asleep in logs is not suitable, since there is an increased level of humidity in the bathhouse.

To waterproof the insulating layer, you can use polyethylene film

When insulating the floor in a bathhouse, a number of features should be taken into account:

Floor insulation using expanded clay in buildings on stilts significantly extends the service life of the room and makes the bathhouse warm, reliable and comfortable. The main condition is compliance with all technological requirements during repairs. We will describe each type of screed with expanded clay in more detail below.

The use of expanded clay significantly extends the service life of the screed

The versatility of the material allows it to be used in different ways. The main criteria for choosing installation technology are the type of room and the relevant circumstances. At the moment, there are three main installations of expanded clay screed:

Expanded clay concrete mixture is widely used for various construction works.

Regardless of the type of screed application technology chosen, the base should be prepared in advance. This is a separate stage that requires special attention.

The list of necessary tools depends on the choice of type of screed. It should be noted that in any case you will need:

Necessary list of tools required for floor screed

A sufficient amount of water should also be provided, especially for the implementation of bulk and typesetting technology. You may need self-tapping screws for setting the beacons and, accordingly, a screwdriver or screwdriver. Ordinary mastic is suitable for smoothing seams. We should not forget about the presence of a construction tape for calculating the material and marking the beacons.

This kind of construction work is quite labor-intensive and dirty. Therefore, you should take care of appropriate clothing, footwear and personal protective equipment in advance.

When starting work on floor insulation with expanded clay, you should calculate not only the mass of the required material, but also the expected load on the screed. To do this, calculate the height of the expanded clay layer and the thickness of the cement-sand floor screed. For example, to effectively insulate the floor on the first floor, the layer thickness must be at least 10 cm.

Scheme of floor screed with expanded clay on the ground

To prepare the solution, it is better to take a ready-made sand concrete mixture, where the proportions are clearly calculated. It contains plasticizers that prevent the screed from spreading and make the solution more plastic. The amount of material for sand-concrete screed is calculated using the formula:

AhBxS/D=K

Where:

For example, the estimated area is 20 m², for screed you need 2 kg of ready-made mortar per 1 m². The thickness of the tie is 10 cm, and the weight of one bag is 25 kg.

As a result, we get the following material calculation: 20 × 2 × 100/25 = 80 bags of dry mixture. Accordingly, with a smaller layer of concrete and in a small room, significantly less material will be required.

Scheme of dry floor screed using beacons under gypsum fiber boards

Before starting work, reinforcement or masonry mesh is laid on the floor. Next, beacons are installed at a distance of one and a half meters, fixing them in level with alabaster. You can make smaller indents, but this will cause difficulties when working with the rule. The floor is marked using a level. It is better to take water or laser. First, marks are made at the required height along the perimeter of the room, and then the required distance is measured from them.

The base for the screed should first be prepared by leveling the surface, and then waterproofed. An ordinary polyethylene film is suitable for this. It is placed with an overlap of at least 10 cm if laid in strips. The allowances on the walls should be slightly higher than the height of the screed. It is necessary to take into account such points as the thickness of the film, and the overlap of the strips should reach 50 cm.

Waterproofing can be achieved using hydrosol or bitumen-polymer liquid mastic. The material is applied with a brush to the floor and the lower part of the wall just above the border of the screed. The surface is covered with mastic twice at three-hour intervals.

As part of the preparatory work, it may be necessary to install fittings. Its installation is simplified by multi-layer filling. Installation is carried out before applying the leveling layer.

Filling the floor with expanded clay along the beacons will guarantee a flat surface

Next, beacons are installed along the filling levels. They are made from any available material, for example, from straight profiles for drywall. The installation of beacons is carried out on the base in a solution. The fastest and most effective solution is gypsum. The rule is also easy to make yourself from a piece of board.

An edge damper tape is fixed along the perimeter of the walls, which compensates for temperature fluctuations. It is better to take a product with a self-adhesive side. A simple tape can be attached in any other way. Reliable fixation is not needed - the tape will only be needed during pouring.

To prepare the solution, take expanded clay of the appropriate fraction. For this purpose, the following proportions are used:

Before preparing the solution, expanded clay is soaked in water. Dry and poorly soaked granules may simply float to the surface of the mixture. Next, fill and level the solution along the beacons.

Scheme for pouring a surface using expanded clay concrete

If the floor with expanded clay is poured in multiple layers, then in order to obtain a uniform screed, the leveling layer must be poured immediately after the first layer. Thus, the process of laying an expanded clay concrete screed is identical to the process of laying a conventional screed. The differences lie only in the preparation of the mixture.

The thickness of the screed itself is of great importance. If it exceeds 6 cm, then it is poured in two layers. Moreover, the first of them is about 4 cm, the second is thinner. It is applied to the required floor level. The finishing layer solution itself is thicker; it is poured in small batches. If you plan to insulate with expanded clay under a ceramic tile floor, then this method is the most acceptable.

Laying a screed on an uneven base in a section

Dry screed technology is relatively simple, and therefore it is very popular. Its essence lies in the fact that expanded clay is poured onto a plastic film, the surface is leveled, and boards or gypsum fiber sheets are laid on top. However, the procedure itself includes a lot of nuances. To do everything correctly, you must follow the instructions and carry out the work in stages. The screeding process includes the following steps:

For laying GVL slabs, a ready-made expanded clay mixture is used.

The dry method of applying expanded clay screed has its advantages compared to other methods, in particular:

The value of such a screed lies in the fact that it puts virtually no pressure on the floor slabs, since the expanded clay is not weighted with concrete mortar.

Scheme for marking the level of dry floor screed with expanded clay

As with any other type of screed, for the dry method it is better to take expanded clay of different fractions in different proportions. The main disadvantage of a dry screed is that only electric or film heated floors can be installed on it. It is impossible to install a water heating system under such a screed.

You should not trust the screed to inexperienced craftsmen, because the slightest violation of technology can lead to irreversible consequences. At best, the floor will simply make sounds when walking, at worst, it will lead to subsidence and deformation of the coating. Unscrupulous workers resort to a number of tricks, for example, they use crushed expanded clay, and instead of gypsum fiber sheets they use other slabs that are unsuitable for such work.

Also, owners should be wary if there is a noticeable gap between the sheets and the wall or if the folds at the point of contact are not cut. The sheets are connected and fixed using polyurethane foam, and not using glue.

Packaged expanded clay is much higher in quality sold in bulk

There are also cases when unprofessional use of even very high-quality materials leads to rapid deformation of the floor, and it sag under the weight of people. Such actions by amateurs discredit the dry screed method itself, making the semi-dry method or pouring the leaders. In fact, a successful result depends on the right approach to business and experience in this field of construction.

The backfill or stacking method is a middle option between dry technology and pouring expanded clay concrete. Based on the intended purpose, different fractions of the material and their combinations are used. To achieve the maximum thermal insulation effect, the expanded clay layer must be at least 10 cm, the granule fraction must be 20 mm. To prepare the filling, use finer-grained material with a fraction of 5-10 mm.

The stacking technology is not suitable for rooms where water ingress is possible. Therefore, it is imperative to carry out moisture-proofing measures on the first and basement floors.

The stacking method of floor screed with expanded clay is best used in rooms where high humidity is not expected

The technology itself consists of filling expanded clay under a floor screed and includes the following steps:

Expanded clay of any fraction is suitable for dry backfilling of the floor, the main thing is that the granules are of the correct shape

This “average” technology between the dry and wet methods of laying expanded clay makes it universal in use both as an independent screed and as part of “pies” of several layers.

Recently, a new type of dry backfill “Compevit” has become especially popular. This material is used during the installation of dry screed using the Knauf method. Initially, the material was developed as floor insulation, but its further use showed that it is excellent for leveling surfaces.

The “Compevit” mixture is very small grains of expanded clay (up to 5 mm), which are easily distributed on any surface. The main requirements for such granules: they must be finely crushed and round. If they do not meet these requirements, then they should not be used. Otherwise, after laying the base with GVL slabs, the expanded clay chips will shrink, and the floor covering itself will be deformed. The oval and asymmetrical shape of the granules also negatively affects the degree of shrinkage of the material.

Compoevit backfill can be used to create warm floors

The Knauf method using Compavit has a number of advantages, namely:

The main advantage of such a floor is its ability to withstand high loads without deformation - up to 900 kg per 1 m². Thus, an affordable price combined with high quality and ease of installation will ensure a long service life of the floor.

The scope of use of expanded clay is quite wide. But the main direction is its use as insulation. At the same time, most of the positive consumer reviews concern precisely such an area of ​​application as floor screed. While people encounter certain difficulties when insulating ceilings and walls, they practically never arise when pouring floors.

Expanded clay is widely used for insulation and construction work of all types

A special place is given to filling attic spaces with this method, as well as the floor between joists during the construction of private houses and country houses. In addition, they point out such a positive quality of the material as its low cost. In practice, floor insulation with expanded clay is 4 times cheaper than using other materials, and the result will be no worse.

Expanded clay receives negative reviews mainly due to the fact that a large amount of material is required to carry out the work. To achieve the maximum insulation effect, you need to use a fairly thick expanded clay layer, which occupies a significant part of the space.

Experts advise using the material in accordance with technology in private homes, utility rooms and garages. Expanded clay is not suitable for high-rise buildings due to its heavy weight. The exception is the first and basement floors.

Before screeding with expanded clay, it is necessary to prepare the room

Experts and experienced craftsmen recommend using a number of tricks:

Scheme of combined floor insulation using expanded clay

If you follow all the rules and technologies, it is quite possible to make a floor screed with expanded clay with your own hands. Video materials, of which there are many on the Internet, will help facilitate the process. As a result, you can not think about repairing the floors of your home for a long time, while ensuring maximum heat and sound insulation. In addition, you can easily eliminate all floor unevenness using expanded clay. The photos clearly demonstrate both the installation process and the positive result obtained.

Which expanded clay is best for floor insulation?

When classifying expanded clay, the size of its granules can be chosen as a basis. The division into factions is as follows:

• The fraction from 5 to 10 mm is used for the production of expanded clay concrete blocks and when pouring screeds.
• Granules from 10 to 20 mm are the answer to the question of what fraction of expanded clay is used to insulate floors or ceilings in houses.
• Fractions from 20 to 40 mm are used to insulate basements, roofs, garage floors and heating mains.

If you put the second and third fractions into the screed, its thickness will increase.

Device instructions

Combined screed with expanded clay

Scheme of a combined screed. As mentioned above, this technology involves the presence of a dry layer of bulk material at the bottom and a wet cement pour at the top. Installing a semi-dry floor screed with expanded clay with your own hands must be done in the following order:

1. cover the clean, prepared surface with roll waterproofing or cover with a layer of bituminous primer;
2. fill in a layer of expanded clay with a fraction size of 5-20 mm, 30-40 mm below the future level of the screed;
3. compact the bulk material well and level with the rule;
4. prepare cement laitance and pour it over the surface;
5. after setting, which will occur in a day, install beacons corresponding to the level of the screed on the frozen surface;
6. prepare cement mortar in a ratio of 1:3 or 1:4 to sand;
7. pour the solution between the beacons in strips and level it with a plaster rule;
8. the top layer of the screed must be pierced with a thin rod with a pitch between holes of no more than 100 mm;
9. Over the next two days, the surface must be periodically moistened with water.

The complete readiness of the screed is determined at the rate of 5-7 days for each centimeter of the cement layer. After this, you can proceed to laying the finishing floor coverings.

Wet screeds with expanded clay

“Wet” screed - pouring the base with expanded clay concrete and then leveling the surface. Laying the concrete layer is carried out in the following sequence:

1. pour dry expanded clay into a tray or other container and fill it with water for 10-12 hours to soak;
2. install beacons on the surface of the base that will determine the horizontal level of the future floor;
3. pour wet expanded clay (4 parts) into a concrete mixer, then add a little water and cement (1 part);
4. After stirring for a short time, add sand (3 parts). Stir the mixture until ready - at least 4 minutes. If necessary, add water during mixing (the consistency of thick sour cream is required);
5. To level the surface, use a plaster rule, which must be pulled along the beacons with transverse movements of the tool.

If, after the screed has set, floating expanded clay granules are visible on the surface, they must be sanded using a power tool. If there are a large number of such granules, you will have to lay an additional layer of self-leveling mixture on top. The complete drying time is 28 days.

Dry screeds with expanded clay

To install a dry screed, you need to purchase fine expanded clay or crushed granules, sheet material such as chipboard or plywood, sand, cement and a plasticizer. The order of work is as follows:

• Cover the surface of the base with dry expanded clay and level the surface using a level lath. When laying a construction bubble level on the slats, periodically check the level of the layer;
• remove beacons;
• lay sheet material on the expanded clay so that it covers the entire surface;

GVL laying diagram.

• check the horizontal position of the sheets using a level;
• cover the second row of sheet material in the same way. The only thing that needs to be provided is that the shift of the seams of the second layer relative to the first should not be less than 20 cm.

After this, you can begin laying the topcoat.

You can see the construction of expanded clay screed clearly and in more detail in the presented video.

Advantages and disadvantages of expanded clay

Advantages

The advantages of expanded clay include:

• good thermal insulation and sound insulation;
• fire resistance;
• high strength;
• durability;
• frost resistance;
• environmental friendliness.

Floor insulation with expanded clay under a screed can be chosen for a number of reasons:

• Expanded clay is exceptional in that it can be poured onto any base, even onto the ground, on which foam or mineral wool cannot be placed directly, as they will quickly lose their useful qualities.
• Expanded clay has the greatest strength among other insulation materials.
• The environmentally friendly composition ensures that expanded clay is safe to use, since it does not release anything into the air.
• Due to its non-flammability, expanded clay has no restrictions in terms of fire safety; it can even serve as a barrier to open flames.
• Expanded clay is the cheapest insulation material, so insulating floors with expanded clay in a private home, as well as walls and ceilings, has long been widely used. In addition to private buildings, it is widely used in industrial and other buildings.

Flaws

A significant disadvantage of floor insulation with expanded clay is its strong hygroscopicity. When its granules are actively saturated with water, they completely lose their heat-protective properties, and do not release moisture back for a long time. Damp, heavy expanded clay begins to sag, and unevenly, which leads to deformation of the floor, which must be taken into account if insulation with expanded clay and screeding of the floors of the 1st floor are carried out. To avoid this, when installing floors, you need to carry out reliable waterproofing.

Usage

Most often, expanded clay is used specifically for the improvement of floor coverings, as insulation. It is poured in a small even layer, so that there are no gaps anywhere through which cold air could penetrate. And then this layer can be filled with concrete or covered with wood. Expanded clay is also used as wall insulation, but this is an infrequent practice, since the process is quite labor-intensive, but, on the other hand, a building with walls insulated in this way practically does not cool at all in winter. This material is also used for insulating the ceiling and the entire roof as a whole.

However, despite the positive properties, you must remember to do everything correctly, otherwise the efforts will not be worth anything. But as was said, expanded clay is very easy to install, which makes it attractive to use even by inexperienced people.

Methods of insulation with expanded clay

Builders use three methods of adding expanded clay:

• wet;
• dry;
• combined.

To make the technology of floor insulation with expanded clay more understandable, you should understand each option in more detail.

Dry insulation with expanded clay

This is how floor insulation is usually done with expanded clay in a wooden house.

1. The material is poured between the beacons or joists, and a subfloor made of plywood, chipboard or ordinary boards is mounted above it.
2. To protect the insulation from moisture, it is necessary to lay a waterproofing material underneath it.

To increase the density of filling granules, it is recommended to take different fractions of them and mix them before filling.

This is a very quick method of insulation that does not require much labor.

Video about the dry method of insulating a floor with expanded clay:

Wet laying of expanded clay

Here a screed is made from expanded clay concrete. Liquid concrete is mixed with expanded clay, after which it fills the space between the beacons.

This is a very convenient method when working with floors that have large differences in height and which require a thick leveling screed. Expanded clay greatly facilitates it, which can significantly reduce the load on the base.

In addition, the screed dries faster and cracks less. But the use of the wet method leads to the fact that the thermal conductivity of expanded clay that has collected moisture increases greatly.

Combined method

Insulation of a concrete floor with expanded clay under a screed is done as follows:

1. Dry expanded clay is poured between the beacons.
2. Then it is leveled.
3. Its uppermost layer is watered with liquid cement mortar.
4. When it dries, a regular screed is made on top.

The cement mortar forms a crust on the top layer of expanded clay and does not allow the lower layers to be deformed when pouring the screed.

If a large load is expected during the operation of the floor, then you can also supplement the structure with reinforcing mesh.

Pros and cons of insulation

Any type of thermal insulation material has its strengths and weaknesses. Ceramic granules also have them. However, unlike other types of insulation, many of the pros and cons of floor insulation with expanded clay are not so obvious and are worth talking about in more detail.

Among the advantages :

• good thermal insulation properties. True, they are achieved only with the help of a thick layer of expanded clay;
• low cost per unit of material (we are not talking about the total cost of insulation);
• durability - a long service life of 40-60 years is possible subject to operating conditions;
• fire safety - insulation is classified as non-combustible materials (class NG);
• resistance to very low and high temperatures;
• frost resistance - withstands 150-300 frosts, which is important when insulating floors on the ground, on balconies and loggias;
• light weight - there are no significant loads on the concrete floor. However, the wooden subfloor must be made of boards at least 25 mm thick with a layer of expanded clay more than 10 cm thick;
• environmentally friendly - does not emit harmful substances when heated or in a fire. Not an allergen;
• biological resistance - is not a food base or habitat for rodents. Colonies of microorganisms do not develop on expanded clay: mold and fungus;
• ability to be one of the components of cement mortars;
• simple and convenient installation that does not require experience in construction work.

The disadvantages are relative, as they manifest themselves in conditions of violation of insulation technology or the occurrence of unforeseen situations:

• the highest level of moisture absorption among all types of insulation - up to 25%. If it gets wet, the thermal insulation properties sharply decrease, and at low temperatures, the ceramic granules are destroyed;
• rather low strength, and therefore, when dumping, you cannot walk on a thin layer of insulation - under the weight of a person, some of the pellets will be crushed;
• the significant thickness of the thermal insulation layer does not allow the use of this type of insulation in rooms with low ceilings;
• the tendency of granules to form dust during filling.

Insulation with expanded clay under a wooden floor on a concrete base

Materials and tools

To insulate a wooden floor with expanded clay, you will need:

• jigsaw or hacksaw;
• nail puller;
• pencil;
• roulette;
• hammer;
• building level;
• electric drill;
• shovel;
• self-tapping screws;
• damper tape;
• coating material or film waterproofing;
• sand.

This example examines the insulation of the first floor floor with expanded clay on a concrete base.

Dismantling the coating

1. It is necessary to remove the floor boards and take them out of the room.
2. Carefully inspect the logs and check their position with a level.
3. Rotten logs need to be replaced, and new ones should be leveled.
4. If the beams are in good condition, not deformed and have no deflections, then they can be left.
5. If the damage is minor, it is enough to replace individual beams, but if they are rotten or loose, then you need to remove everything right down to the concrete.

Surface preparation

1. Clear the base of the floor from debris, repair small cracks and inspect the corners - if there are deep cracks, they need to be filled with foam or covered with mortar.
2. The joints around the perimeter of the walls and floor should also be filled with foam.
3. Then you need to pour a layer of sand onto the base and compact it thoroughly, but if coating waterproofing is used, then there is no need for sand.

Waterproofing

1. A special membrane or plastic film must be spread on the floor so that it covers the walls by 7-10 cm with its excess.
2. The logs should also be under the film.

When the width of the canvas is not enough, you can lay several pieces overlapping and secure the joints between them with construction tape.

1. Fix the waterproofing on the beams with a stapler, having first tucked it well in the recesses between the joists

1. If coating waterproofing is used, the mixture must be applied to concrete that has been cleaned of dust, including sections of walls near the floor. With this option, the logs should be on top of the protective layer. It can be coated with liquid polymers, bitumen mastic, polymer-cement based mastics and bitumen-polymer mixtures. The composition should be applied in 2-3 layers at intervals of 3 hours, so such waterproofing will take a lot of time.

1. Finally, you need to fix a damper tape at the height of the subfloor along the perimeter of the walls, which will resist cracking and deformation of the screed during temperature changes.

Installation of logs

1. If the old logs had to be completely dismantled, then new ones must be installed. For this purpose, durable wooden beams or boards are suitable, which need to be cut to the length of the floor, then soaked in an antiseptic and completely dried.
2. The wooden frame on the floor must be at least 10 cm high.
3. The outermost joists should be located 2-3 centimeters from the walls, and the step between adjacent joists should be within 50-100 cm.
4. All logs must be placed parallel to each other and at the same level, so that their upper surfaces all lie together on the same, strictly horizontal plane.
5. The joists need to be secured to the floor using metal corners: screw one side of the corner with screws or self-tapping screws to the joist, and the other to the floor.
6. The extreme corners should be 2-3 cm from the edges of the joists, and the step between adjacent corners should be within 50 cm.

Expanded clay backfill

Before forming a layer of expanded clay to insulate the floor, you need to mix its large and small fractions, and then pour it between the joists.

The question of what layer of expanded clay is needed for floor insulation is simply resolved - after it is leveled until all voids are eliminated and compacted (carefully so as not to crush the granules), the level of expanded clay should not be higher than the top edge of the joists.

All that remains is to lay waterproofing on top and secure it with a stapler.

Flooring installation

A subfloor made of boards, chipboard or plywood must be attached to the beams protruding from the insulation layer, after which the finishing coating can be laid. The film sticking out near the walls can be cut with a knife and the gaps can be closed with decorative skirting boards.

Materials and tools

To insulate a concrete floor and a rough wooden floor, you will need almost the same materials and tools. Therefore, we present a universal list. Materials you need to buy:

• expanded clay - fraction and grade depend on the location of the work;
• wooden beam for laying logs;
• sheets of plywood, OSB or GVL, if the floor installation will be without logs;
• wood screws for attaching the logs to the supporting beam through the top (long) or metal corners (U-shaped profile) from the side, 3-4 cm long;
• metal corners or U-shaped profile for attaching the timber to the concrete base;
• damper tape;
• polyethylene film or any other rolled waterproofing material (you can use polymer mixtures or bitumen mastics).

To perform the work you need a set of tools. You can buy it, collect it from friends and neighbors, or rent it. During the work you will have to use:

• a screwdriver with a powerful battery (replaces an electric drill);
• jigsaw or wood hacksaw;
• vibrating plate – necessary for compacting expanded clay when insulating an earthen floor;
• bucket;
• tape measure;
• a rule or a straight slat;
• a level, preferably a laser one;
• shovel;
• nail puller;
• marker or construction pencil;
• stapler;
• with a hammer if you bought nails instead of screws.

Insulation with expanded clay under a wooden floor on the ground

Sometimes, instead of a concrete base, there is soil under the floor; in this case, it is necessary to insulate the floor with expanded clay over the soil in the following sequence:

• Level and compact the soil.
• Add about 10 cm of gravel.
• Fill the gravel with sand and compact it tightly.
• Next, add insulation, and the thickness of the expanded clay layer should be 15-25 cm.
• Having leveled the insulation layer, it is necessary to fill it with concrete on top.
• You can lay a wooden floor.

Practical recommendations for dry leveling of expanded clay backfill

First, we’ll talk about gross technological errors that cause the floor surface to sag.

What not to do

Never use drywall. The fact is that this is the worst building material in terms of all physical characteristics. It has no strength, is afraid of water, does not hold hardware, etc. Even the so-called moisture-resistant board loses its properties after several hours of direct contact with water. If you don’t believe me, put a piece of it in a container of water. Such a practical experiment will allow you to clearly see false advertising by manufacturers. Another problem is that plasterboards laid flat bend under their own weight. Why is this material so often used by builders in various architectural structures? The explanation is simple - it is very easy to work with him, and this makes it possible to significantly increase salaries. In the case of expanded clay, it is difficult to achieve a perfectly flat surface; the slabs under the voids will certainly bend. As a result, you will have to redo the floors, and this is very time-consuming, labor-intensive, dusty and expensive.

When leveling expanded clay, do not make stationary beacons using cement-sand mortar. The fact is that expanded clay itself gives a slight additional shrinkage over time

Have you noticed how a initially large pile of sand decreases in height over time? Grains of sand gradually occupy free spaces, the size of the heap decreases, and this does not require rain. The same processes occur with bulk expanded clay, only on a smaller scale. The surface reduces the height and the cement beacons always remain in a stable position

As a result, over time they rise above the plane of expanded clay, and tubercles and depressions appear on the dry screed.

How to level the base

The correct technology will cost you much more than other methods of leveling the base for the final floor covering. Keep this in mind before making your final decision.

1. To level the surface of expanded clay, use special devices. This is a professional tool, consisting of two long aluminum slats and a rule that can be moved by it. As the work progresses, the tool is transferred to a new location, leaving behind perfectly flat surfaces, and there are no stationary beacons. It is not economically profitable for non-professionals to buy these tools; such devices significantly increase the estimated cost of the floor.
2. You need to work with the laser constantly on; the beam continuously controls the horizontal plane of the expanded clay. Walking on an already prepared surface is strictly prohibited.
3. Prepare the base in sections; immediately cover the prepared small areas with durable slabs of extruded polystyrene foam at least five centimeters thick. Why do you need additional insulation, since expanded clay itself is used as a heat insulator? The heat-saving properties of this material can only be considered more or less satisfactory when air movement completely stops. It should be noted that the bulk layer of large granules is well blown by air currents; due to the convention, warm masses rise upward, and cold masses take their place. Continuous movement occurs, the efficiency of heat conservation decreases sharply. If leveling is done using the wet method, the solution not only binds the moving granules, but also prevents the removal of heat.
4. Expanded polystyrene materials cannot support heavy loads; their surface must be protected. Cement-fiber boards (fiber cement) performed well. The addition of cement significantly increases strength indicators; a slab with a thickness of only one centimeter is capable of withstanding the maximum dynamic and static forces on floor coverings possible in residential premises. These materials are widely used and, in all technical parameters, are excellent for dry screed. If the floors are not loaded, then GVL can be used; they are cheaper, but in terms of physical properties they are noticeably inferior to their cement analogues. To increase the stability of the structure, the joints must be coated with a special glue - the entire surface becomes monolithic, the base does not sag.
5. Expanded clay is afraid of getting wet, the consequences will always be very sad. Professional builders strongly recommend covering the surface of the dry screed with waterproofing material. It should be remembered that high-quality mastics are quite expensive. By the way, after pouring expanded clay with concrete mortar, there is no need to perform additional insulation measures.

Insulation with expanded clay under a concrete base

Floor preparation

In this case, standard preparation of the subfloor is performed:

1. It is necessary to dismantle the old coating, seal all the cracks, and clean the surface from dust.
2. After this, lay a film on the base or cover it with liquid waterproofing. To cover all the joints along the perimeter of the floor, the film must be placed on the walls.
3. Finally, at the level of the future screed, you need to secure the damper tape, after which you can proceed to insulation.

Installation of beacons

Metal beacons are required here; U-shaped aluminum slats are best suited for this.

1. To fix the beacons you need to mix a little gypsum or cement mortar.
2. The first lath must be laid on the mortar under the wall located opposite the doorway. Its position must be carefully checked with a level, and, if necessary, raised or pressed into the solution.
3. The distance between the beacons should be 50-100 cm, and the height of each should be no more than 10 cm.

Expanded clay backfill

First you need to calculate how much expanded clay you need to insulate the floor. According to the standard for 1 sq. m area you need 0.01 cubic meters. m of expanded clay with a layer thickness of 1 cm. That is, the required amount depends on the thickness of the intended insulation layer and the area of ​​the room.

Expanded clay thickness for floor insulation:

• On the 1st floor and above unheated rooms - 10 cm.
• On the 2nd and above floors in residential premises - 3-4 cm.

For example:

• In a room of 20 sq. m you need 10 cm of insulation thickness (expanded clay).
• With a thickness of expanded clay of 10 cm, you need 0.1 cubic meters. m per 1 sq. m area.
• For 20 sq. m of area will need 0.1 * 20 = 2 cubic meters. m of expanded clay (1 cubic meter of expanded clay = 400 kg).

1. The resulting quantity must be prepared by mixing its different fractions.
2. Then you need to fill the entire space between the beacons with this mixture, leveling the material with a piece of plywood or a rule.
3. Particular care must be taken to fill joints and corners so that there are no voids left there.
4. Then the expanded clay must be compacted carefully so as not to damage the granules.

Reinforcement

Place a large-mesh metal mesh on top of the insulation, which should be 4-5 cm away from the walls everywhere. The mesh should have no sharp protruding edges, bulges or dents.

Performing a screed

1. The mixture for the screed should consist of 1 part cement and 3 parts sifted sand, which must be mixed well with water until an even thick consistency is obtained, then pour it in portions between the guides on the floor.
2. The mixture must be leveled with a long rule, running it along the beacons and removing its excess.

After this, you need to wait until the concrete gains sufficient strength to lay the floor.

This floor insulation with expanded clay assumes that the screed is laid directly on the insulation without additional insulation.

Video about floor insulation with expanded clay under a screed:

Characteristic

A little more about the properties of this material:

• Thermal conductivity. If you compare expanded clay with wood or brick, then 10 cm of expanded clay will retain heat in the same way as a layer of 30 cm of wood or 100 cm of brick. That is, it retains heat 3 times better than wood and 10 times better than brick. These are very serious numbers.
• Strength. Since expanded clay is most often used for floors, although it is also suitable for walls and ceilings, it must withstand constant loads. Depending on the density of different brands, the strength can range from 250 kg to 600 kg.
• It has excellent sound insulation; in typical multi-storey buildings this is very important.
• Since expanded clay is made of clay, its service life is very long. For example, a floor made of this material will survive a typical nine-story building.
• Good resistance to fire, heat, frost and chemical influences. Expanded clay has excellent resistance to temperature fluctuations. More precisely, temperature changes do not affect it in any way.
• Weight. Expanded clay is lightweight, so even over a large area, expanded clay will not require additional reinforcing frames or structures.
• Price. Wholesale sales of expanded clay start from $2.5 per 20-kilogram bag.
• Easy to install. The use of expanded clay only involves general preparatory work (remove the old coating).

The only disadvantage of this material is its low moisture resistance. Clay is not capable of passing water, and it retains it in itself, so when water gets on this material, it accumulates. But this problem is easily solved by following all installation rules.

Expanded clay concrete screed

If the subfloor is very uneven or you need to significantly raise the floor level, then this requires an expanded clay concrete screed:

1. At first, the surface also needs to be cleaned of dirt and dust.
2. Then apply foam along the joints and cracks and apply waterproofing.
3. Then you can begin the main process.
4. Secure metal beacons to the floor using cement mortar.

1. Having mixed cement and sifted sand in a ratio of 1:2, add 3-5 parts of expanded clay (this depends on the expected load on the floor) and 1 part of water.

1. Fill the space between the beacons with the mixture 2-3 cm below their level.

1. Compact and level the surface, to do this, drown the floating granules in the solution again.
2. As soon as the screed has set slightly, prepare regular concrete without additives and pour it over the screed, then level it according to the beacons.

The screed should dry for 3-4 weeks. In the first days, its surface must be watered so that cracks do not form on it. The result is a warm and durable base that can last a long time. When the surface of the screed can be walked on, it should be covered with a water barrier or film.

How did you insulate the floor with expanded clay, and why did you choose it? Write your answer in the comments - your experience is important to us.

Reviews

“Not long ago I made repairs and insulated the floors in the hallway, toilet and bathroom. First I made waterproofing, after which I poured expanded clay (it turned out to be 10 centimeters in height). I filled everything with “cement laitance” on top. After 20 hours, I covered everything with sand concrete and repeated this several times. Expanded clay did not float, the screed dried without cracks. When everything was completely dry, I laid the tiles. The floors are much warmer, although a little higher.”

Sergey, Nizhny Novgorod.

“I don’t sell expanded clay and don’t try to advertise it, saying that it’s a super material. In fact: I had it in a bathhouse, the first floor was a log house, and the second floor was filled. I always had enough insulation, flooded it - and after an hour and a half I could already steam. On the second floor they calmly undressed. Friends came constantly, and no one ever complained that it was cold or the bathhouse was cooling down quickly.”

Vladimir, Yaroslavl.

“We had a sloping floor in our living room, which made the furniture doors difficult to open and scratched the laminate flooring.
We hired workers to level the floor; they measured a level difference of 11 cm. They advised us to level it with expanded clay and insulate it at the same time. We had waterproofing done for the entire room; expanded clay and dry mortar were mixed right on the floor in portions. They spread it out and knead it again, so the entire area. We waited a long time for everything to dry, and then laid the laminate flooring. The floor is now both smooth and warm.” Marina, Moscow

Features of expanded clay concrete

Expanded clay concrete differs from the usual concrete mixture in the type of filler: instead of crushed stone, expanded clay is placed in it - a bulk material obtained from baked clay. It gives the solution special properties.

A few words about expanded clay

Made from natural raw materials, expanded clay is an environmentally friendly material. Thanks to special production technology, it is light in weight, has a porous structure and has high thermal insulation and sound insulation properties.

At the same time, it does not rot, does not corrode, and does not contribute to the development of microorganisms, so, unlike other insulation materials, it can be used for screeding on the ground.

The material is classified according to the shape and size of the fractions. Concrete screed with expanded clay of different fractions has different purposes.

The volumetric bulk mass of the material in kilograms per cubic meter, and ultimately the weight of the expanded clay concrete screed, depends on the grain size. The volumetric mass is reflected in the grade of expanded clay (from 150 to 800).

The price of expanded clay is higher than crushed stone. But it also provides many advantages as a concrete mixture. And not only in the mixture. Lightweight and free-flowing, it allows you to level surfaces with large differences in heights without creating a serious load on the floors.