Lightweight screed with expanded clay. Advantages of expanded clay screed: process technology and nuances. Bulk coating on expanded clay screed

When they begin to consider the issue of floor insulation, then experts from the very beginning discourage the introduction of complex systems, since the most common ones are quite able to cope with this task.

Therefore, you should not spend money and effort on the installation of complex structures, but it makes sense to learn how to make a floor screed with expanded clay with your own hands.

It is so easy to work with this material that anyone can handle the screed device, no special equipment or tools are needed.

The only thing you have to pay attention to is the thickness of the layer being laid. It must be at least three centimeters. As a rule, expanded clay is used when it is required to level the floors in all rooms.

Such problems often have to be solved, and the material is often used for floor insulation in private houses, apartments and other premises. Light weight makes expanded clay even more popular when installing insulating screeds, since the whole structure does not weigh down the floor slabs, which have an individual margin of safety. If you want to organize a screed with a thickness of more than 10 cm, then it should be made not just from a pure mixture of sand and cement, but with the addition of a lightweight filler - expanded clay. Foam chips or gypsum-fiber sheets are also often used.

If they do not inspire confidence, and you decide to insulate the floor yourself, a floor screed with expanded clay is what you need. Is it difficult to do it yourself?

Screed using expanded clay

Let's look at how a do-it-yourself floor screed with expanded clay is performed. The process is not difficult, but it will require attention and effort. Expanded clay is ordinary clay balls subjected to heat treatment. In other words, burnt clay.

The level of the future floor

First, you should determine the line along which it will be necessary to level the floor. It is convenient to use laser or As a result, horizontal lines should appear on the walls of the room, along which the surface will be leveled.

Elimination of defects in the subfloor

After the level of the future floor is applied to the walls, it is necessary to get rid of various defects. You should not hope that the screed itself will fill in all the bumps, recesses and chips, since you have to fill the floor with expanded clay, and therefore there is a possibility that you will not be able to get rid of all the flaws. Therefore, it is better not to spare time and money and seal them with a liquid solution similar to that which will be prepared for the screed.

Installation of beacons

The next important step in the screed device is the installation of leveling beacons. To do this, you will have to determine where the highest point of the base of the floor is located. Exactly in this place, the first of the beacons should be installed. This is the most important moment when a do-it-yourself floor screed with expanded clay is made.

Lighthouses are ordinary guides made of metal, sometimes made of plastic. They are laid along or across the room, thus dividing it into sections. Expanded clay is poured between the lighthouses.

In order for all the guides to be in the same plane, wooden wedges or just pieces of boards or plywood are placed under them. However, you can do it even easier: dilute the gypsum with water and lay this pasty mass in a slide along the intended installation site of the guide. Put the lighthouse on a hill and evenly distribute the solution using a level.

To align long beacons, it is convenient to use a rule or level with a length of two meters or more. When determining the distance between the guides, they proceed precisely from the size of the rule: the beacons are positioned so that it is convenient to place the tool on two adjacent guides or on three. If, for example, the width of the room is four meters, then beacons should be located at a distance of no more than 70 cm, because then the level will cover not two, but three guides, which will positively affect the speed and quality of the work performed.

Backfilling the base with expanded clay

After the beacons are set and leveled, it is necessary to fill the floor with expanded clay. It can be considered that it is almost completed. Expanded clay falls asleep strictly along the marked areas that limit the lighthouses. Backfilling is considered the easiest step in the construction of a screed. The main thing is to monitor the height of the expanded clay layer. It should be evenly distributed so that there is still enough space for the screed itself, that is, for a mixture of cement and sand. In other words, the expanded clay layer should be such that there is still 25-20 mm left to the top level of the beacons. After the expanded clay is evenly covered between the beacons, we prepare the "milk" of the cement. They fill our heater.

The role of cement laitance

This solution is a material designed to hold the insulation together. As a result, it will be possible to safely walk on the expanded clay layer. In addition, the solution covers the granules with a special film that will reliably protect them from moisture, otherwise moisture from the liquid will be absorbed into the expanded clay. This is also necessary because if the screed loses moisture, the quality of the cement mortar will inevitably decrease. Subsequently, cracks, chips and other defects will appear. In other words, do-it-yourself floor screed with expanded clay made in this way will lose strength.

Proportions for the preparation of cement milk

It should be understood that this is the same cement-sand mortar, only in liquid form. Here you can not do without experiments. Three times more water must be poured into a mixture of cement and sand than for a conventional screed. Then fill a separate small area with expanded clay with the resulting solution and look at the behavior of the mixture. If it spilled through the expanded clay, and there was not a trace left on the granules, then too much water was added. If there is a residual layer of milk on top of the insulation, we can conclude that there is not enough water. A compromise must be found.

After the entire surface is filled with cement milk, it is necessary to allow it to dry completely. This takes at least a day. Only then can you begin the next stage of work, which will be the actual floor screed with expanded clay with your own hands.

Preparation of mortar for screed

To prepare a screed mortar, cement of a grade not lower than M400 and building sand are used, which are mixed in a ratio of 1: 3, respectively. In this case, it is better to use a special rather than a conventional shovel.

Remember that usually two liters of water are added per ten kilograms of the mixture. It is much more convenient to pour the solution into water, and not vice versa, although the instructions attached to the cement often indicate the “wrong” way.

Using a mixer, the mixture is thoroughly mixed for 5-10 minutes. Then leave for 5 minutes to settle, and after five minutes, mix again for about 2-3 minutes. Now the solution can be used.

Pouring mortar on the floor

When pouring the solution on the floor, it is leveled with a trowel, applying, if necessary, a rule to distribute the composition evenly over the entire floor. The rule is placed on the beacons and the cement mass is stretched over the entire area, trying to ensure that the surface assumes a strictly horizontal position, and there are no bumps and depressions. This is exactly how the floor screed with expanded clay is done with your own hands.

How to quickly prepare a solution

There is an easier way to lay expanded clay insulation under the screed. The preparation of the base is done in the same way as described above. Only the solution is prepared differently. Water is poured into the container and expanded clay is poured. After that, it is poured, which is thoroughly and quickly mixed and placed between the beacons.

Thus, do-it-yourself floor screed is made even faster: expanded clay is a material that will help speed up the process. However, when choosing this option, it is extremely difficult to guess with the proportions of its components. In this case, it is recommended to use ready-made mixtures, which are sold in hardware stores and markets. They are poured into a container where water has already been poured and expanded clay has been added. In another way, this method is also called "wet".

There is a "dry" option, and this is also a floor screed with expanded clay. Features of the technology are that much less water is added. If such a solution is taken in the palm of your hand and clenched into a fist, then liquid should not drip from it. But the breakdown of the mixture is also unacceptable. After such a solution is distributed between the beacons, it must be compacted. It dries quickly enough, and this allows you to start the next stages of construction work without spending time on drying.

This is how a standard do-it-yourself floor screed with expanded clay is performed. The instruction may vary depending on the specific conditions, but the principle of its creation is the same for most rooms in which there is a need to level the floors.

Saving money is the main trump card in our difficult time. Do not be afraid that you will not be able to screed the floor with expanded clay: do-it-yourself screeding is a simple process, the most important thing is to follow the technology and do not forget about some important points. Then it will serve you faithfully for a long time, and you will not have to constantly repair the floors.

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

To make expanded clay concrete with your own hands, you will need expanded granules with a particle size of 5-10 or 5-20 mm with a bulk density of 600-700 kg / m3. Fine sand is not as effective, but is used for thin pouring up to 30 mm. Large fractions are more 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 size classes from 5 to 40 mm are present in equal proportions. In this case, the screed is a little more dense and heavy, but strong enough. At the same time, the consumption of cement 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 differences, reaching 10-15 cm.

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

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

Fine-grained aggregates are also subject to increased requirements, since they are also capable of influencing the strength characteristics of expanded clay concrete. This is ordinary 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 larger fractions 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. You can use air-entraining modifiers such as SDO, which additionally porous 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 scope of work, you will need to measure the area of ​​\u200b\u200bthe room and calculate the height of the future layer of expanded clay concrete. The volume of pouring is the amount of clay filler in cubic meters, from which one should build on in further calculations. A “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, 140-200 liters of water per cubic meter of solution will be enough for such proportions. If soaking was not effective enough, the amount of liquid can be increased to 300 l/m3.

Traditionally, builders use a simplified ratio to obtain claydite concrete of brand strength M100 - optimal for the installation of a "warm" screed on their own. To do this, take 1 part of cement:

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

With such proportions, you can even purchase sand cement, where bulk materials just go in a ratio of 1: 3. 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 a screed device in domestic 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.

Light 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. Having added 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 in the manufacturing process should become the same gray color - without brown spots.

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

Cooking must 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 over the installed beacons. A solution with expanded clay filler 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 spread under load and collect dust. Also, a damper tape must be fixed around the perimeter of the room to compensate for thermal expansion. Upon completion of the work, the expanded clay concrete screed will require additional protection against moisture evaporation. To do this, it is covered with a film on top, which can be removed after a couple of days.

The finished layer of "warm" concrete needs final leveling - preferably with preliminary grinding. From above, it is poured with a conventional sand cement mortar with a thickness of not more than 30 mm (without the addition of gravel). This is enough to hide the irregularities, but not worsen the thermal insulation characteristics of the rough base. Finishing pouring is carried out along the beacons, carefully leveling the mixture with the rule. Reiki is carefully removed the next day, and the remaining traces are sealed with a fresh composition.

A semi-dry screed is another option for insulating and leveling the floor with 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 shed with a 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 considered “wet” method.

When repairing floors, even in a private house, even in an apartment, in about half of the cases, the owner thinks about a cement screed, because modern floor coverings provide for an even and strictly horizontal base, which 15-20 years ago were considered almost wasteful. In this article, we will analyze the process of installing a cement screed with expanded clay with our own hands.

Getting such a foundation in another way is a rather difficult task, and besides, it’s expensive, especially if the floor level in different rooms is seriously different, but you really want to remove the creepy thresholds worn to the point of losing geometry. In addition, sometimes you just can’t do without a screed.

But what kind of screed to make is not only a matter of taste. Screeds are:

• cement-sand (including with various fillers and plasticizers);
• concrete, based on cement mortar and crushed stone;
• polystyrene concrete;
• expanded clay concrete.

We deliberately do not take into account various dry screeds, considering them, as a special case of flooring, concrete screeds with heavy fillers, except for crushed stone, taking into account that they differ little from the latter in the context of solving this problem.

Therefore, if you have a slight difference in height and it will be enough to simply level the floor surface, and the thickness of the screed in the largest places will not exceed 10 - 12 mm, then take a ready-made self-leveling floor mixture, and strictly following the instructions, apply it to the floor. This is a cement-sand screed with fillers and plasticizers.

You can replace it by preparing a 1: 3 cement-sand mortar, where 1 part of cement (better than 500 grade), which is 5 kg per 15-liter bucket, 3 parts of sand (better than fine river) and add 50 - 80 g of liquid soap, 80 - 100 g of the smallest polypropylene fiber and half a glass of dispersed PVA. Make the consistency the same as the most liquid store sour cream. For this, 7-8 liters of water will go, depending on the moisture content of the sand, the properties of cement, etc. Write down this composition. We will also need it for a do-it-yourself floor screed with expanded clay and cement, which we will describe below in the form of detailed instructions.

We strongly do not recommend using concretes based on crushed stone and other things on floor slabs, and even more so on wooden floors. That's what they call heavy. Their weight can be critical, because less than 5 cm such screeds do not work, and then, in most cases, they also need to use self-leveling compounds.

If the difference in floor heights across the room is large enough, and (or) it is necessary to raise the floor level from 70 to 150 mm, then it is advisable to consider expanded clay and polystyrene foam screeds. Polystyrene concrete screeds are good because they significantly insulate the floor, but if this is not required, then expanded clay concrete screed is usually used, as the most inexpensive.

Preparatory work before performing expanded clay screed

Due to the fact that the preparatory stage for the installation of all cement screeds on the floors is almost the same, we moved it into a separate small section, with which we will begin our step-by-step instructions for installing a claydite screed with our own hands.

First, you need to dismantle the old floor covering, repair (if necessary) the base, filling the cracks that have formed, filling the voids that have formed.

Secondly, mark the floor level using a laser or water level, having beaten off a horizontal line along the perimeter of the room at a convenient height. You can easily determine the level of the real floor or the level of the screed from this line after the following steps. Yes, if you don’t really want to apply this line on the walls in order to avoid their further repair, which is almost impossible with a screed, you can use metal pins with bright heads, stuck into the walls with a certain step along the laser line. With a water level, this method is extremely burdensome.

Thirdly, to waterproof the room using sheets of geomembrane welded together or strips of dense polyethylene.

You can also use ready-made waterproofing mastic.

Fourth, stick a damper tape around the perimeter to compensate for temperature fluctuations that are not very expected with such a floor, but possible. It is necessary to glue it so that the upper edge is a few centimeters above the level of the finished floor.

Fifthly, stick a wide masking tape and mark the level of your screed with a marker on it, setting aside the desired distance from the upper level line.

On this, the preparation for the installation of a floor screed using expanded clay and cement (or other) can be considered completed.

Traditional expanded clay concrete screed

For it, a simple cement-sand mortar is used in a cement-sand ratio of 1: 3, or simply ordered in the form of a ready-made expanded clay concrete mixture at the factory, if it is nearby, which will be economically feasible.

And if there isn't one, then...

The amount of expanded clay in such a composition can be anything, but if we are talking about lightweight concrete, then it is maximum. It must be added until the liquid creamy cement-sand-water mixture envelops the expanded clay pellets well.

Laying should be carried out either along the beacons, or guided by the marks on the walls, if there is still a sufficient leveling layer on top.

The simplest do-it-yourself expanded clay screed device with cement

The previous section may have broken our step-by-step instructions for installing an expanded clay screed using cement, but it was necessary to understand that this method of its production can also be applied. But with it, it is extremely difficult to completely prevent leakage through the ceilings, and in terms of readiness time, it is not very interesting.

And we will continue the instructions with a description, in our opinion, of a more technologically advanced method:

Sixthly, we calculate the required amount of materials for our expanded clay screed. The calculation of the covering materials used before is simple, and comes down to two indicators - area and perimeter, so we did not describe it. Now we are adding height and bulk materials, which are most conveniently considered volumetric quantities.

To do this, we calculate the average height of the screed by repeatedly measuring it in different places of the room with different levels of the lower point of the subfloor, adding the obtained values ​​\u200b\u200band together and dividing the result by the number of measurements. Further, from the result obtained, we subtract 30 mm of the leveling beacon layer and get the height of the expanded clay layer, multiplying which by the floor area, we get the total volume of expanded clay.

In our case, this will be the volume of the entire lower layer of the entire screed, because the cement mortar used to fasten it will be embedded in the expanded clay layer, and will not add height or volume.

This view has the lower layer of the expanded clay screed we offer.

Expanded clay should be bought exclusively by volume, because. depending on the quality and characteristics of the feedstock - clay, the characteristics of the technological process and other factors, its weight can vary greatly. The fraction must be taken in the middle so that the solution penetrates well, and there are no large voids between the pellets.

To calculate the cement-sand mortar, we recall the composition proposed above. Some adjustments can be made to it, namely: replace half of the cement with ceramic tile adhesive, which will help retain water, and add 1.5 - 2 kg of slaked lime. At the same time, fiber can not be added to the bottom layer, which will hold the expanded clay.

For 2 bags of expanded clay, approximately one 15-liter bucket of a creamy solution will go. For him, in turn, 3 kg of cement and tile adhesive are used. Sand - according to the state of the solution. You need to fill it up after connecting all the components. Only in this way will you get the necessary consistency, which will penetrate into the expanded clay layer by 2 - 3 cm and no more.

Reinforcing meshes are calculated by area, taking into account a small overlap.

Seventh, instead of traditional lighthouses, we offer lighthouse posts, which are quite simple to make using any container, forming them according to the principle of children's sand bees, making a very thick solution. After shrinkage, it will be possible to correct the level, which will be the level of the finished expanded clay cement screed.

The reinforcement above them is cut out in place.

Eighthly, expanded clay is evenly scattered on the floor and leveled at a level 30 mm below the rule set for the beacon columns.

It is convenient to work with 1 bag of expanded clay, it is easy to get to the farthest point and control the level.

Ninth, prepare the solution by taking 6 - 7 liters of water, pouring the above ingredients into it, at the end, adding water and adding sand, bring the amount to the full volume of a 15-liter bucket.

Spill expanded clay gradually, leveling with a spatula with slight vibration, so that there is a good penetration of the solution and wetting of expanded clay by 2-3 cm.

With this formation of a claydite-cement cake, it will be possible to safely walk on it after 15-20 hours, if the room is at room temperature. The traditional expanded clay concrete screed will allow this to be done no earlier than after 3-5 days, depending on the thickness.

Tenth, on the second day, you can cut and lay out the armature mesh, prepare a solution of the same composition, but with the addition of fiber, but thicker, make beacons from it between the level columns.

They, with small blunders, press down the mesh in places where it does not adhere well to the expanded clay concrete base, but not higher than the general level of the upper layer.

Eleventh, carefully prime the surface with a deep penetration primer. We propose to do this with the most ordinary cheap atomizer screwed onto a plastic bottle. The layer must be thick enough.

Twelfth, after the cement beacons have dried, prepare a solution of the consistency of homemade sour cream

and perform a 30 mm thick top layer screed.

If you do it carefully enough, then this will be a ready-made base for laying laminate, parquet, fiberboard, and even more so - tiles.

If you have to lay linoleum or lay carpet, then we would recommend additionally shedding the base with the thinnest layer of self-leveling compound.

Tiles can be laid the next day, and coatings that are afraid of moisture - after 5 days, checking the moisture with a glass jar. It must be put upside down on a screed. If after 10 - 12 hours moisture condenses on its walls - you need to wait more, and if it is dry - feel free to lay the finish coat.

Dear readers, if you still have questions, ask them using the form below. We will be glad to communicate with you;)

- a widely known and long-used building material, 30-40 years ago it was one of the few types of insulation. It does not satisfy modern developers either in terms of the quality of heat saving parameters or in terms of manufacturability of application. Currently, the construction market offers consumers a wide range of heaters that are far superior to expanded clay in all performance characteristics. But there are cases when it also makes it possible to achieve optimal results when performing some construction work. Which ones - we will consider a little lower, and now we should briefly dwell on the properties of the material. This knowledge will help to avoid most mistakes during the floor screed on expanded clay.

Expanded clay is obtained by special processing of clay, as a result of which porosity and a granular structure are imparted to it, and performance characteristics change.

1. Thermal conductivity. Depending on the size of the granules and the characteristics of the technological process, the thermal conductivity varies within 0.16 W/m×°C. This is an order of magnitude worse than it has or mineral wool. In addition, the exact heat-saving properties are very difficult to calculate, which significantly complicates the design of buildings according to the actual values ​​of heat loss.

   

2. Mechanical strength. Granules can withstand loads up to 5.5 MPa, which is much more than modern heat insulators. But not everything is so simple. Manufacturers indicate the strength of one expanded clay granule, and it is used in bulk. When walking on it, deep pits are formed, although the granules are intact, the insulated base requires additional construction measures to ensure stability. It is impossible to install finishing coatings on bulk expanded clay.

   

3. The material is completely fireproof. It is recommended to use it to create a barrier that prevents the spread of open flame throughout the room.
4. Environmental Safety. It means that expanded clay is made of natural clay and does not emit harmful chemical compounds into the air.

   

5. Expanded clay does not rot and is not afraid of temperature changes. This makes it possible to use it directly on the ground. But it easily absorbs moisture and it is very difficult to evaporate it. In case of emergency wetting of the insulation, the material sharply reduces its characteristics. It is impossible to dry it naturally, you have to completely dismantle the flooring.
6. There is no need to specially prepare the surface of the base. It may have large cracks and differences in height. Everything that does not affect the bearing performance of the floor may not be sealed. Some builders do not remove garbage either, unless its size exceeds the height of the poured expanded clay. Such properties greatly reduce the amount of construction work, reduce the cost and speed up flooring.

   

7. Low cost. The price of insulation is much lower than modern materials used today.

   

We have listed the most important properties of the material, indicating the advantages and disadvantages, the decision on the choice is made after a detailed analysis of the milestones of the individual characteristics of the object.

Despite the clear advantage of modern heaters in all important characteristics, there are cases when the use of expanded clay is considered the best option.

Table. When is the best time to use expanded clay?

Step-by-step instructions for floor screed with expanded clay

Step 1. Preparatory work. It is necessary to calculate the amount of expanded clay and cement-sand mixture, buy a reinforcing mesh. Check the availability of tools that are missing to buy or borrow for a while. Preparatory work is carried out in several stages.

Now it remains to measure the distance from the base to the upper plane of the expanded clay backfill, multiply the length and width of the room by the height of the layer and get the desired volume of material. Each bag of expanded clay has a marking indicating this parameter.

According to the same algorithm, the volume of the mixture for the screed is determined. Leave a small margin for unexpected expenses and buy materials.

Step 2 Pour expanded clay on the floor, level its surface. Constantly monitor the thickness, adhere to the previously set parameters for the height of each layer.

Step 3 Spill a layer of insulation with liquid concrete. It is recommended to buy ready-made dry mixes in specialized stores. Making a solution at home is very inconvenient, and sometimes impossible. For 40 kg of sand concrete, add 10 liters of water, mix the solution thoroughly, do not leave lumps. The consistency of the mixture should resemble fat-free kefir. For pouring, you can use a metal ladle of a bricklayer or adapt an ordinary plastic container. Wait a few hours, time is needed for the sand concrete to gain strength. After pouring, the filled expanded clay loses its mobility, which makes it possible to continue work and not damage the linearity of the plane.

Step 4 Install metal or plastic on the floor. If significant loads are planned on the flooring, then professionals recommend using a traditional metal mesh, it gives a much more positive effect. Why? Everything is very simple. For optimal performance, the plastic mesh must be stretched and perfectly even. If this condition is not met, then the free-lying fishing line easily moves in concrete and does not create additional obstacles to breaking. And it is even theoretically impossible to perfectly align the grid on an uneven expanded clay base. The metal mesh is always even, its cells constantly hold the concrete.

Step 5 Prepare . The operation must be taken very carefully, the quality of the surface depends on it.

Step 6 Proceed to the screed. Prepare the solution, stir the mixture thoroughly. The process is much easier if you have an electric mixer. The solution must be prepared according to the technology prescribed by the manufacturer, strictly follow its recommendations.

1. Pour the required amount of water into the container, add the dry mixture to it.
2. Mix the solution with a mixer at medium speed, add dry ingredient or water as necessary.

Important. It is desirable to prepare the solution in a respirator. It contains cement, and this is a rather aggressive chemical compound.

Step 7 Gradually fill the floor area with a solution, start from the farthest corner and move towards the exit from the room. Pre-align it with a trowel, make an exact fit using the rule. The movement of the tool must be reciprocating. This not only facilitates the process of tightening the excess, but also prevents the appearance of bumps and scuffs on the surface of the screed.

Using the same method, make a screed on the entire surface of the floor. After hardening, check the quality, for this, use a ruler or a homemade template and a laser. Set the beam on a horizontal line and in several places check the distance from it to the screed. The spread in the corners of the room cannot exceed a few millimeters.

Checking with a template is faster and easier. It is done very simply. Take any piece of a wooden river or a metal profile, put it against the wall and make a mark with a pencil or a construction felt-tip pen. Walk with the template around the room and check the position of the mark and the laser beam.

What is a dry screed

There are articles on the Internet that use the concept for leveling expanded clay. As an example, the use of various boards is considered: GVL, OSB, plywood. Strictly speaking, this is not a dry screed, but an ordinary leveling of the base with the help of plates. It is used on various types of floors, but for expanded clay is considered the most unfortunate option. Why? The plates do not fix the top layer of expanded clay granules, and this is very bad for several reasons. First, the floor does not have sufficient stability. Secondly, while walking on it, there is a possibility of unpleasant sounds: the granules move slightly and rub against each other.

A dry screed with a high degree of conventionality can be called a semi-dry cement mixture screed. This solution contains a minimal amount of water, when squeezed in the hand, moisture does not appear between the fingers. But this is a completely different technology; in the case of expanded clay, it is used very rarely. The fact is that wet filling fixes the granules, due to which the surface strength is significantly increased. In this regard, we gave step-by-step instructions for this particular technology. For those wishing to still make the so-called dry screed, we will give some professional advice.

Expanded clay - expanded burnt clay. Inside - a porous formation, outside - a sintered shell.

Expanded clay was successfully used before the advent of modern heaters, as a high-quality and inexpensive heat insulator. In some cases, it is still used in this capacity. When working on floor screed, the material is used for leveling and as a mortar filler. It is fired, foamed clay granules of different fractions and shapes.

Advantages:

• thermal insulation qualities. Within 0.07 - 0.16 W / (m * K). For comparison: foam plastic 0.031 - 0.04, mineral wool 0.045 - 0.07, reinforced concrete 2.0 - 2.04;
• mechanical load. Compressive strength from 0.6 to 5.5 MPa. For comparison: polystyrene 0.03 - 0.4 MPa, concrete 5 - 60 MPa and above;
• Moisture resistance. Water absorption 8 - 20%. A long time in water does not destroy the material;
• The material is fireproof. Non-flammable, does not emit any toxic substances when exposed to high temperatures;
• Biologically inert. Does not rot and is not a breeding ground for microorganisms;
• Rodents do not start in filling expanded clay. The mobility of the backfill does not allow making moves and arranging nests;
• Noise absorption. Achieved only when added to a cement screed, and not with a dry backfill;
• Over a long period of time, the properties of a quality material do not deteriorate. In many old buildings (more than 50 years old), during the demolition, expanded clay is found, with which nothing happened;
• The properties are not affected by temperature changes in any climatic zones;
• Low cost and availability;
• It does not require any special tools or skills to work. A floor screed with expanded clay is essentially no different from a standard floor screed.

Flaws:

• For insulation, a large thickness of the screed is required. A layer with expanded clay with a thickness of less than 10 cm is ineffective;
• A dry floor screed with expanded clay is dangerous if water enters the expanded clay layer. The material itself will not be affected, but the moisture under the concrete will remain, which can lead to increased dampness inside the room and the formation of mold.

Expanded clay for floor screed is not suitable for everyone. It is recommended to use different brands depending on specific cases and places of application. Which expanded clay is better in one case or another is determined by the parameters: layer thickness, laying method (bulk layer or expanded clay concrete), the presence of water, etc.

There is GOST 32496-2013 for the characteristics of expanded clay grains. However, manufacturers may not adhere to it, releasing products to their own specifications or simply not maintaining the standard. In particular, when purchasing material from an unknown manufacturer, there is a risk of buying material with an increased background radiation. At least there are warnings.

The main parameter is the grain size of the fractions: 5 - 10, 10 - 20, 20 - 40 mm. Also, several conditionally divided into:

The first two types are used as heat-insulating material. It is possible to make a screed with expanded clay sand, but only as a porous filler for concrete. At the same time, the characteristics of the concrete pavement will not differ much from ordinary concrete in terms of thermal insulation.

The use of expanded clay for floor screed

In terms of thermal insulation qualities, the material is inferior to a number of modern heaters: expanded polystyrene, mineral wool and other foamed, porous and fibrous synthetic heaters. This is especially critical in rooms with low ceilings. For reliable thermal insulation, the expanded clay layer should be from 10 cm and above, while using foam plastic, 5 cm is sufficient (in specific situations, it may be less).

In what cases is it advisable to use expanded clay:

• To reduce the pressure of the screed on the base. Expanded clay concrete is much lighter than ordinary concrete;
• In cases where the insulated floor will experience significant weight loads: garages, industrial premises, etc.;
• Arrangement of "warm" floors. It is convenient to place heat-conducting communications directly on expanded clay. In this case, the material will also act as a heat-insulating cushion. With this technology, the equipment of the "warm" floor should be above the heat-insulating pad (deepened flush with it, but no more). There should be as few heat-insulating elements as possible between the heat conductors and the finished floor (a thin layer of ordinary screed, self-leveling floor, decorative finish). Nevertheless, it is better to use modern heaters - extruded polystyrene foam or, in extreme cases, foam;
• Situational for leveling the surface, reducing the consumption of concrete. It is usually cheaper to level with various construction debris or soil. The quality is better than soil, clay or building scrap. Does not require additional tamping, practically does not shrink.

For screed with expanded clay, three methods and their combinations are used:

• Expanded clay concrete. When mixing a concrete solution, expanded clay is introduced in different proportions and different fractions, depending on the purpose;
• Zasypnoy. Expanded clay is not mixed with concrete, but simply piled up (heat-insulating layer, leveling, like a filler). This layer can subsequently be both isolated from liquid concrete and concrete poured directly onto it;
• "Dry" screed. In fact, this is a layer of expanded clay covered with sheet flooring material (gypsum fiber, plywood, chipboard, DSP).

Expanded clay concrete

To obtain an insulating layer, a thickness of expanded clay concrete of at least 10 - 15 cm is required. No preliminary preparation of the base before pouring is required. The exception is large ground irregularities (pits, dips), which are recommended to be filled and compacted beforehand. Waterproofing is also done on the basis of general construction indications. Those. if there is a need for hydroprotection of the structure from groundwater, high humidity.

The process of laying a claydite concrete screed is identical to the process of laying a conventional screed. The only difference is in the preparation of the mixture.

Advice! If the thickness of the screed is more than 6 cm, then for simplicity it is poured in two layers. The first layer is 4-5 cm short of the floor level. The second layer is leveling.

Stages of expanded clay concrete screed:

1. Floor level markings. The markup can be done using the building level or the water level (preferably).

   

   Markup using the water level. First, the level is marked at any convenient height around the entire perimeter of the room. Then the required distance is measured from these marks.

2. Foundation preparation (if necessary). Filling holes, leveling large irregularities. waterproofing measures. As a waterproofing, it is enough to use a plastic film. It is advisable to place the film with a slight overlap (10 - 15 cm) if several strips are applied. It is also desirable to make small allowances on the walls up to the width of the screed.

   

   Waterproofing with polyethylene film.

3. Installation of fittings (if necessary). Multi-layer casting simplifies the installation of reinforcement. In this case, the reinforcement is placed before the leveling layer is poured.

   

   Installation of reinforcing mesh.

4. Installation of beacons according to the fill level. Beacons are made in any way, they are installed on the base on the solution (gypsum solutions can be used to speed up). Instead of specialized beacons, you can use any straight profile (for example, a wall profile for drywall). The rule can also be made independently from a piece of the board.

   

   Installation of beacons on the solution.

5. An edge damper tape is installed along the walls. Serves to compensate for temperature fluctuations. Sold in different types, including with a self-adhesive side. You can also attach it to the wall by any method: double-sided tape, glue, stapler.

   

   Fixation of the damper tape is needed only at the time of pouring, the durability of the fastening is not required.

6. Preparation of expanded clay concrete. Fractions and species depends on the goals. Insulating properties are higher for large fractions of gravel. Crushed stone and expanded clay sand are used for thin leveling layers. Proportions of approximately 1 cement (M400), 3 building sand, 4 expanded clay. Expanded clay is pre-soaked in water, not saturated with moisture, the granules will float to the surface of the concrete.
7. Filling and leveling on beacons. For multi-layer pouring, in order to obtain a homogeneous screed, it is recommended to pour a leveling layer immediately after the first layer.
   

The method is used both as an independent screed and as one of the layers in multi-layer pouring. Under tiles, self-leveling floors on this screed are quite sufficient.

Zasypnoy

Something between a dry screed and expanded clay concrete. Also, depending on the purpose, different fractions and types are used. For thermal insulation, the expanded clay layer must be at least 10 cm, and the gravel fraction from 20 mm. For leveling, smaller fractions, crushed stone and sand are preferable. The backfill method is not advisable to use when there is a high risk of direct water ingress. Moisture isolation, if necessary, on the first and semi-basement floors is required.

In fact, this is an expanded clay screed device:

1. Floor level markings.
2. Foundation preparation (if necessary).
3. Installation of beacons according to the fill level.
4. Backfilling and leveling of the expanded clay layer. Sometimes, to improve the insulation properties, you can additionally lay a layer of waterproofing from a liquid solution - an ordinary plastic film. It is desirable to shed the top layer of expanded clay with a liquid solution so that it does not float when pouring the screed and it is convenient to install beacons. The only plus is that expanded clay will not float when pouring a sand-cement screed if the solution is too liquid. The polyethylene film also prevents the granules from floating.
5. Installation of fittings (if necessary).
6. Filling the sand-cement screed on top. It is recommended to dilute the solution thicker, in smaller batches, or to prevent the granules from floating by the above methods.

The method is also used as an independent screed, and as part of multi-layer "pies".

Dry screed

Dry screed is of two types:

Technology:

Advice! It is not necessary to do the whole room at once. Can be done in parts according to the size of GVL sheets. In this case, a smaller number of beacons will be required, it is more convenient to move along the laid floor. Otherwise, to move, you will either need to start laying from the entrance, or arrange islands to move along the poured expanded clay (in this case, it is enough to temporarily lay GVL sheets).

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