INSTRUCTIONS AND PROPHECIES OF THE Blessed MOTHER ALIPIA GOLOSEEVSKY, Kyiv...
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.
To obtain such a foundation in another way is a rather difficult task, and besides, it is expensive, especially if the floor level is different rooms is seriously different, but I really want to remove the creepy, worn out to the loss of geometry, thresholds. 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 most big places does 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 brand 500), which is 5 kg for a 15-liter bucket, 3 parts of sand (preferably fine river sand) and add 50 - 80 g 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.
Concrete based on crushed stone and other things on floor slabs, and even more so on wooden floors, we do not recommend using it. 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 in that 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 preparatory stage for the installation of all cement screeds on the floors is almost the same, we moved it to a separate small section, with which we will begin our step by step instructions on the device of a screed with expanded clay with their 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, to mark the floor level, using a laser or water level, having beaten off a horizontal line along the perimeter of the room on comfortable 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 along the laser line with a certain step. 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 desired distance from the top 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 as volumetric quantities.
To do this, we calculate the average height of the screed, repeatedly measuring it in different places in the room with different levels the bottom point of the subfloor by adding the values obtained 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, flow characteristics technological process and other factors, its weight can fluctuate 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 glue for ceramic tiles, 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 sandbags, 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, and 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 help of the most ordinary cheap atomizer screwed on 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 this carefully enough, then this will be the finished base for laying the laminate, parquet board, 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 very next day, and coatings that are afraid of moisture can be laid in 5 days after checking the humidity 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;)
During operation, depending on the intended purpose, a number of technical requirements. These are strength, evenness, the maximum value of the specific load, the degree of thermal insulation, and so on.
General description of expanded clay concrete
An excellent option in terms of price, quality and speed of installation of the floor surface is the laying of a concrete screed, which provides perfect evenness and high wear resistance. However, of this type The floor has a number of disadvantages - this is a high specific gravity per unit area and a low degree of thermal insulation throughout the depth of the surface. Expanded clay concrete screed, which is lightweight concrete, retains the advantages of a conventional concrete screed, but is devoid of its shortcomings.
The method of obtaining expanded clay concrete for floor screed is simple and differs from the classic concrete mortar, consisting of cement, sand, water and crushed stone, only in that expanded clay is used instead of crushed stone. It has the form of gravel with a porous structure in the form of an oval of various fractions from 5 to 40 mm, it is produced industrially, by firing clay or its derivatives. Variability is determined by the type of implemented construction works. The smallest is used for the production of expanded clay concrete screed and the production of blocks, the middle one is used for bulk insulation of the floor and ceilings, the large one is used for thermal insulation of outbuildings and heating mains.
Types and scope of expanded clay concrete
The classification of expanded clay concrete is quite extensive and depends on the requirements for the type of product produced, the density of the granules, the application and solidity. All these signs are standardized by the brand (for example, expanded clay concrete M100), which determines the class of its application and varies from 35 to 100 kg / cm²:
Claydite concrete grade | Application area |
arrangement load-bearing structures building partition walls inside the building |
|
erection of load-bearing structures in the construction of residential and industrial buildings |
|
floor screed |
|
production of expanded clay concrete blocks |
|
And floor slabs |
|
installation of engineering structures with a large periodic load |
Taking into account the area of application, the density of expanded clay concrete is an important characteristic, which is determined by the ratio of mass to volume of the material and has limits from 700 to 1400 kg / cm². Often in buildings of old and not very old construction, for a number of reasons (foundation subsidence, unskilled installation), there are significant differences in the floor level of adjacent rooms, and sometimes even within the same room. Leveling to a single level with a conventional cement-sand screed can seriously increase the load on the supporting elements of the building, which is highly undesirable, especially when it comes to multi-storey buildings.
Due to the porosity of the screed, the density of heavy concrete is much less, which determines the unconditional priority of its use in such a situation. Increasing the percentage of cement in expanded clay concrete increases the strength of the structure, however, there is a significant increase (up to 1.5 times) in the weight of concrete. Accordingly, the maximum possible reduction of the cement component of the material allows to reduce its volumetric weight. In this regard, the grade of Portland cement used in its production must be at least 400.
Benefits of using expanded clay concrete
And it does not sink in water, and does not burn in fire. Low thermal conductivity determines the high heat resistance of expanded clay concrete, which means long-term resistance of the material to high temperatures. Even at temperatures above 1000 °C, claydite concrete retains its mechanical properties. The material shows itself very well when exposed to moisture. Unlike stones, which, having been soaked with water in frost, are destroyed, expanded clay concrete has high frost resistance, that is, the ability to freeze and thaw repeatedly without loss of strength.
Another important factor determining the priority choice of expanded clay as a filler for concrete is its environmental friendliness. He does not highlight harmful substances neither when exposed to an aggressive environment, nor over time, nor with complete destruction. This explains its choice as building material and insulation in living quarters.
Preparation of the base for pouring the floor with expanded clay concrete
If the screed is made over an existing even and dense coating, then this stage of work can be skipped. However, most often pouring is performed directly on the ground, in which case additional preparation of the base is required. The surface is leveled and carefully compacted, the pits are covered with sand, the protrusions are knocked down for uniform laying of the pillow. The pillow is a layer of sand about 2-3 cm and a layer of expanded clay or crushed stone 3-5 cm thick, or more, up to the level of the draft base. Next, a plastic film or roofing felt is laid to waterproof the future screed, a masonry mesh is mounted and beacons are installed.
Types and methods of using expanded clay screeds
Having dealt with basic properties and technical characteristics of expanded clay concrete, its pros and cons, let's try to understand how to properly fill the floor using this material. The choice of the type of expanded clay concrete screed depends on the type of base on which it is produced, and therefore floor screeds can be of three types. Let's consider each of them.
Dry screed
Expanded clay gravel is evenly and without being distributed over the previously prepared, cleaned and compacted base surface, not reaching 2 cm to the lower level of the lighthouse. in this case is determined by the required degree of thermal insulation. Next, the entire area is poured with cement milk, which is made by mixing cement with a large amount of water without adding sand. This procedure will fix the expanded clay and cover the gravel with a thin protective layer, which prevents moisture from being drawn out of the finishing screed, which will give additional strength to the floor. After that, the usual thin screed is performed. The advantages of this method are the speed of installation, the disadvantages are low surface strength.
Wet screed
With this option, so much water is added to the solution so that light and porous expanded clay floats to the surface after pouring the screed. The hardening of concrete takes a little longer, all the filler is concentrated at the top of the screed. The advantages include self-leveling of the mixture. The disadvantages are long drying, the need for special preparation of the surface to be coated in order to avoid leaks, as well as the subsequent surface screed, if necessary, to obtain a smooth surface. In this way, they are usually insulated attic space and outbuildings.
Semi-dry screed
The most common type of expanded clay concrete pavement, which is identical to conventional concrete in terms of the manufacturing method. For the correct filling of the floor in this way, expanded clay concrete M100 is used. In its manufacture, expanded clay of the first fraction with a diameter of 5-10 mm is taken. The proportions of the mixture are as follows: 1 part of Portland cement grade 400 - 3 parts of sand - 4 parts of expanded clay. As for the amount of water, this parameter must be selected individually, depending on the moisture content of the sand. It is necessary to achieve a consistency in which the granules of the material would not float to the surface, which makes smoothing difficult, at the same time, the solution should not be too dry, as this complicates its installation and can lead to the formation of voids and cracks in the mass of the screed.
The solution is mixed in a concrete mixer or in a large container. The use of a mixer nozzle is extremely problematic due to small portions in one batch, and this makes laying long, the solution turns out to be of different consistency, and expanded clay is distributed unevenly in the mass of concrete. The sequence of mixing the ingredients in different sources is described in different ways, but in practice this is of no fundamental importance. The main thing is that the solution is uniform and the expanded clay granules are completely covered with a binder.
The solution is applied in an even layer over the entire surface to be covered, while it is necessary to observe the condition - the thickness of the expanded clay concrete floor screed must be at least 3 cm, usually it is 4-6 cm. its grouting a day after laying. The advantages of this coating method are obvious - the possibility of using it for any type of floor and ceiling. The disadvantage is the high labor intensity, pouring using beacons and the need for finishing grouting.
Often the floor surface has large differences, especially in newly commissioned properties. Steps between floor slabs can reach a height of up to 10 cm. Level such floors concrete mortar inefficient for two reasons:
- Unprofitable in economic terms - high consumption of material
- The screed turns out to be very massive and dooms the floor slabs to excessive load
To facilitate the entire structure, low-density ingredients are added to the screed, quite often expanded clay plays their role. This material, depending on the size of the granules, has a thermal conductivity coefficient from 0.07 to 0.16 W/m. Knowing how to properly screed on expanded clay, you can arrange a warm floor with good thermal insulation properties.
Experts recommend using expanded clay for leveling the floor with level differences of more than 5 cm. When using this material for screed, it should be borne in mind that its granules have low density and often float to the surface of the solution. It is difficult to determine by experience what layer a screed is poured onto expanded clay so that it evens out all the bumps and does not crack. It is more rational to listen to the advice of experts and make concrete a layer of 2-3 cm. At the same time, the technology for performing work on the installation of a flat floor is divided into stages:
- Drawing a single horizon line throughout the apartment.
- Light fraction flooring.
- Lighthouse installation.
- Leveling fill.
Let's consider each operation in more detail.
A flat floor throughout the apartment without differences between rooms looks beautiful. It is better to mount it at once in all rooms, and not separately - first one, then after a month or two, the next. To obtain the same floor level in the apartment, the zero horizon line is beaten off on all walls.
It is more convenient to mark with the help of a water building level. It will allow you to project a given mark on all walls with an accuracy of 1 mm. Markup using this tool is carried out as follows:
- Stepping back from the floor surface 1-1.5 m in any of the rooms, make a mark on the wall
- The first communicating vessel with divisions is fixed near the drawn risk, moving along the walls, the second horizontal level is marked after 50-60 cm
- According to the marks, the so-called “zero level” is drawn with a straight line
- Stepping back from the highest point of the floor 7 mm (2 mm for concrete + 5 for expanded clay), mark the risk of finishing pouring on the wall
- The screed mark is projected onto all walls and a continuous line is drawn, which will be orienting for the installation of beacons
After repulsing the horizontal, they begin to prepare the surface. The floor is cleaned of construction debris and dust, then sheets of waterproofing material are spread over the entire area with an overlap on the walls to the marked horizontal. As a protection against moisture, you can use a plastic film. The joints between the canvases are overlapped with an overlap of at least 10 cm and glued with moisture-resistant construction tape. Expanded clay is laid on top of the film.
Light layer installation
The material that facilitates the screed is usually classified depending on the size and shape of the fractions into the following groups:
- Rubble. Expanded clay grains of this type are 5-40 mm in size, mostly angular in shape. They are obtained by crushing large pieces of fired foamed clay.
- Expanded clay gravel. This material are round granules Brown color. According to GOST, gravel is divided into fractions of 5-10, 10-20 and 20-40 mm in size. Used as thermal insulation material, facilitating the design of the screed.
- Expanded clay sand. It is obtained by crushing fired clay granules to particles less than 5 mm in size. Sand is used to make light thin screeds.
Expanded clay is mounted in a screed in two ways - by pouring a dry fraction, followed by pouring "cement milk" or laying out a solution. The granules are of low density and, if they are not fixed, they will float through upper layer and form irregularities on the surface of the screed. The most reliable fixing of expanded clay in a single mass occurs when the solution is mixed.
To prepare the mixture, take 1 part of M-500 cement, 2 shares building sand and 7 - expanded clay gravel. Ready solution spread on the floor, making the layer 2.5-3 cm below the drawn horizon line and level with the rule. As soon as the claydite concrete gains initial hardness, at which it is possible to walk on it, they begin to install the beacons.
Attaching guides
Construction beacons are used to control an even pouring layer. They are placed at a distance less than the length of the rule by 10-15 cm from each other. The initial guide is mounted, stepping back from the wall 25-35 cm. To fix the beacons, self-tapping screws are used, which are screwed into expanded clay concrete. The use of screws allows you to smoothly adjust the height of the bar.
Self-tapping screws are screwed in such a way that the top point of the beacon is flush with the marked horizon line. The screws are placed along the entire length of the plank with a distance of 35-55 cm. The even location of the guides relative to each other is controlled using a building level 2 m long.
An alternative option is a device under the beacons of pillows made of cement-sand mixture. With this method, the position of the slats is adjusted by sinking or pulling them out of the pillows. After fixing the beacons, all the remnants of the solution above the guides are carefully removed. Then they wait for the mixture to harden, check the reliability of the fastening of the strips and proceed to pouring.
Surface leveling
The final layer of concrete mix (1 share of M-500 cement for 4 parts of building sand) is poured between the beacons. When manually mixing the solution, dry fractions are first mixed until homogeneous. gray color and then water is added. When using a labor-saving concrete mixer, 1 part water, 1 cement, 4 parts sand are poured into the container and wait until mixed into a homogeneous mass. Experts recommend adding plasticizers to the composition, for example, PVA glue. These substances increase the adhesion of the mortar and prevent cracking of the concrete.
A less labor-intensive, but more expensive method is a screed device using ready-made dry mixes. In addition to plasticizers, their composition includes special components that provide the screed with a long service life. Such mixtures should be diluted strictly following the recommendations of the manufacturers.
The solution prepared by this or that method is laid out on expanded clay concrete and leveled using the rule, which is carried out longitudinally to the beacons in close contact with their upper surface. In order for the concrete to lie evenly, it is distributed by vibratory movements of small amplitude transversely to the guides. When pits occur, a mortar is taken from the front front with a trowel and placed in a defective place.
To make the screed monolithic, experts recommend arranging it in one day. If it is impossible to fill the floor at once in the entire apartment, it is leveled according to the rooms, insulating with a strip 3-4 mm thick, thereby providing a thermal expansion joint.
After 4-5 hours, the concrete will harden and the beacons can be removed, and the resulting voids can be sealed with mortar. So that the screed does not crack, it is recommended to spill it with water from a watering can 1-2 times a day for a week.
Expanded clay facilitates concrete and allows you to make a screed up to 15 cm thick. So if the floors are frightening with drops, you should not stumble over them. Effective remedy to eliminate such defects - a screed in two layers with expanded clay, the installation of which gives the room a completely different look.
AT modern construction along with heaters of the latest generations - mineral wool, polystyrene and expanded polystyrene, does not give up its positions and expanded clay, the most famous and in demand from the category of natural heaters. It has been widely used as an insulating material since the last century. But even today it has not lost its relevance, given its good performance and fairly low price.
Floor screed with expanded clay gravel
What is expanded clay
This material is presented in the form of small granules, obtained in the factory, as a result of firing clay in special drum-type furnaces. Various technology preparation of raw materials, which are clay or shale rocks, as well as drum screens, allows you to get expanded clay of various densities and shapes in accordance with GOST 9759-76. Expanded clay is used not only for floor screeding, but also in the production of lightweight concrete, in which it is a light filler, for the construction of drainage fields, it is also used as a heater for ceilings, heating mains, outdoor water supply systems, and in landscape works for insulating lawns.
Appearance expanded clay A small specific gravity of the granules is acquired due to swelling of the feedstock, which is achieved by exposing the clay to high temperatures.
Briefly about expanded clay production technology
Depending on the state and type of feedstock, one of several technologies is used for the production of expanded clay:
- wet way;
- dry;
- from a powdered mass;
- from wet clay.
With the wet method, raw materials with high humidity are brought to an almost liquid consistency, and the slip is called. In this state, the semi-liquid mass enters the drum-type furnace, where, under the influence of high temperature and gases, it takes the form of individual granules or balls. The method is costly, given the high consumption of the heat source to remove excess moisture from the raw material. However, with this method, it is possible to introduce certain additives into the expanded clay composition that increase it. specifications, as well as clean the mass from various inclusions in the form of stones and other unwanted components.
Expanded clay production The dry method involves crushing dry raw materials if the clay is mined in the form of stones. After that, the crushed mass enters the drum-type furnace and then all according to a single technology. This method is the simplest and most economical.
The production of expanded clay from powdered raw materials consists in the primary crushing of clay almost to the state of dust, after which it is diluted with water. The result is a mass resembling plasticine, from which round or cubic granules are made.
The latest method of expanded clay production resembles the production of red bricks, since the raw material is moistened and sent to special mixers, where it takes the form of a hard clay dough, which is passed through a press or rollers with holes. The output is granules. cylindrical shape, which enter the kiln, where they are dried and sintered.
After passing through the cooling stage, which occurs with a gradual decrease in temperature to give the required strength to expanded clay, the granules enter the fractionation chamber, where they are given a certain shape.
Expanded clay properties
The continuing popularity of insulation made from clay is explained by its characteristics:
- Environmental friendliness, as the product is made from natural raw materials.
- High mechanical strength obtained by sintering clay granules to the state of stone.
- Excellent thermal insulation due to the presence of tiny air chambers in the material, which are formed at the stage of swelling of the clay. A ten-meter layer of expanded clay, in its ability to retain heat, replaces a half-meter brick wall and a thirty-centimeter wooden structure.
- Resistant to sudden changes in temperature.
- Fire resistance.
- Duration of operation.
- Tolerance of contact with acids, alkalis and other chemically aggressive substances.
- Low specific gravity, not exceeding 600 kg / m3, due to which the insulation, even poured in a large layer, does not exert a strong load on the supporting base.
- Low cost with good technical data.
- The ability to lay expanded clay on any base, up to earthen.
With many positive properties, the material has the only drawback - the ability to absorb moisture in large quantities. But this drawback is conditional, and refers to expanded clay insulation, which is filled up without a protective surface layer. For example, expanded clay is specially added to the soil to regulate the water balance, where it is saturated with moisture and releases it when the earth dries.
The use of expanded clay in construction
Most often, the material, which is produced in three versions - expanded clay gravel, crushed stone and sand, is used in such works as floor screed with expanded clay.
Expanded clay classification by size Expanded clay gravel, the diameter of the granules of which varies between 5-40 mm, is used when installing an insulating layer on floors, ceilings, and heating mains.
Crushed stone obtained from sintered clay differs from gravel in its shape and in the size of the granules, which range from 10 to 14 mm in diameter. Expanded clay gravel is most often used in the manufacture of lightweight concrete.
Expanded clay sand, as the name implies, is produced with a granule size of no more than 5 mm in diameter. It is used at the device of couplers of small thickness.
Types of expanded clay screeds
Depending on the functionality of the room and the type of insulated floor structure, it is possible to make a floor screed with expanded clay using one of several technologies:
- semi-dry screed;
- wet;
- dry.
Semi-dry screed
Semi-dry screed with expanded clay Floor screed with semi-dry expanded clay is much easier than all other options. If the laying of expanded clay is supposed to be on the floor of the first floor or on the ground in a private house, then first of all, before making a screed, it is necessary to create a barrier to the access of ground moisture to the insulation. As a waterproofing under the screed, any membrane material, roofing material, glassine, and even inexpensive plastic film is suitable.
The main thing is that the joints of waterproofing materials, which are laid with an overlap of 10-15 cm, must be hermetically glued with masking or ordinary tape, and in the case of using a foil film with an adhesive tape of the same name.
The base must be cleaned of debris, if it is soil, then level and tamp. After that, you can spread the waterproofing. If in the underground space pass electrical cables or wiring, which will later be in the screed, they must be laid in special boxes or corrugated pipes. After that, it is necessary to determine the level of the top of the expanded clay screed. To do this, use a water or laser level. Horizontal marks are made on the walls with a regular marker or pencil.
A gap of 8-10 cm wide must be left along the perimeter of the room for the subsequent installation of a layer of insulation, which will simultaneously perform the function of a sound insulator, since noise is well carried through the joints of the floor slabs to neighboring rooms.
On a note: PC floor slabs are quite profitable to order on the website of the representative office of reinforced concrete plants. The prices are better.
Reinforced screed with expanded clay Expanded clay is poured onto the prepared surface and leveled wooden rule, which looks like a rake, but without teeth. Next, a reinforcing mesh is laid on the expanded clay (if necessary) and a liquid solution is poured from the cement so that the expanded clay gravel absorbs required amount moisture. Otherwise, the insulation will take moisture from the solution with which the main screed will be made, as a result of which its strength will be insufficient and the floor surface will be uneven.
In another option, when the floor is insulated with expanded clay, a film is spread over the dry insulation, which will prevent moisture from seeping into the granules.
Wet screed device
A screed with expanded clay, produced by a wet method, can rightly be called expanded clay concrete, given the composition of the mixture and production technology.
Expanded clay concrete mix for floor screed At the first stage, it is necessary to calculate how much expanded clay, sand and cement will be required, depending on the functionality of the room, the expected loads on the floor. In residential premises, as a rule, a mixture is used, drawn up in proportions of 1: 1: 3: 2, where:
- cement and water is used one by one;
- expanded clay -2 parts;
- sand - 3 parts.
The required volume of the mixture is calculated simple multiplication floor area for the thickness of the screed, taking into account the unevenness of the base base. The horizontal level of the finished base is determined in exactly the same way as in the previous version. Similarly, waterproofing and insulation around the perimeter or damper tape are laid.
To prepare the mixture, a large container is required, where expanded clay is first poured and filled with water 10-15 cm above its level. Such a procedure is necessary in order for the porous structure of expanded clay to absorb as much water as needed. The degree of absorption is determined by the changing color of the granules. They should darken. After that, cement, sand are poured into the container, water is added, if necessary, and all components are thoroughly mixed.
Before laying the mixture of expanded clay concrete on the base, you need to install beacon rails according to the level, thanks to which the work will be done better and faster. Lighthouses can be made of wooden bars or metal profiles. They should be firmly fixed on the base base so that they do not move from their place during the pouring of the expanded clay concrete layer. The mixture is poured between the lighthouse rails and leveled with a rule that must be made of such a size that its edges lie on the lighthouses. Then it will move along them like on rails, and the screed will turn out to be even.
After a couple of days, it will be possible to move along the screed or make a secondary leveling coating, since it will not be possible to achieve ideal evenness for finishing with expanded clay concrete, given the size of the granules.
Check if the base is dry or not folk method. A jar or glass is placed on the screed, bottom up. After some time, if the moisture has not yet evaporated from the expanded clay concrete mixture, drops of condensate will appear on the walls of the vessel. So you can't walk on this floor yet.
How to dry screed
Laying sheets on dry expanded clay The essence of this method is the use of expanded clay and sheets of moisture-resistant drywall, pressed plywood or particle board. The advantages of such a method are as follows:
- in the absence of dirt;
- relatively easy work in the physical plane;
- simple installation of communication networks passing in the underground space;
- minimum load on the ceiling, which is especially significant when such work is carried out in buildings of the old fund;
- maximum degree of thermal insulation;
- the possibility of operation immediately after completion of work.
The implementation of a dry screed begins with the preparation of the base base. It is necessary to remove old floor coverings, debris, repair large cracks and cracks. After that, a layer of waterproofing is spread under the expanded clay on a leveled base. The strips of material are laid with an overlap, the size of which is usually 10-15 cm, and the resulting joints are glued with adhesive tape. Wherein waterproofing material should start on the walls, slightly above the level of the future floor. In the future, visible remains of the waterproofing can be easily cut off and covered with a plinth. A damper tape is glued around the perimeter of the room, which is designed to muffle the noise from the moving sheets of the top layer of the dry screed.
Damper tape laying Now you need to set the beacon rails on a horizontal level. To do this, stock up on such devices and tools as:
- laser or water level;
- screwdriver;
- screwdriver;
- screws of the required length.
Horizon marks are placed on the walls. Beacon rails or metal profiles are placed on heaps of gypsum mortar in accordance with the intended horizontal marks. Why gypsum mortar? The answer is simple, gypsum, unlike cement-sand, sets almost instantly, an obvious time saving.
Between the beacons, a width equal to or slightly less than the length of the rule should be observed. Expanded clay gravel is poured over the entire area of \u200b\u200bthe room, or in separate sections between the lighthouse rails, and is again leveled by the rule. Expanded clay should be lightly tamped, for which a plastic grater is used.
Exposed beacon slats for backfilling expanded clay Under the screed, a substrate in the form of foamed polyethylene foam is sometimes laid, which will give the top layer of plasterboard sheets or other material greater stability and create additional sound insulation.
The final step will be laying sheet material in two layers. When laying out the sheets, it is necessary to observe the dressing of the seams so that the joints of the sheets of the lower layer are located in the middle of the upper ones. Between themselves, the material is fastened with a special glue or self-tapping screws. The seams are glued with sickle tape and sealed with putty.
The main essence of the article
A screed with expanded clay will help make the base warm, create the necessary slope, while the load on the supporting structure will be minimal. The choice of screed device technology and the type of expanded clay depends on the functionality of the room and the expected loads.
Not in all cases, only cement and sand are used to fill the screed. It is often necessary to include various additives in it, for example, expanded clay granules, if the desired thickness should be more than the standard 10-15 millimeters, or if the floor needs to be leveled. This task is not easy, so we strongly recommend that you study our instructions on how to fill the floor with expanded clay, and only then proceed to work.
To begin with, it does not hurt to find out when it is advisable to equip a screed with expanded clay:- The first case is the need to raise the floor level by considerable height. At the same time, the surface strength will be higher than when using the traditional cement-sand tandem.
- In areas with critical temperature regime, as expanded clay screed demonstrates excellent resistance to high temperature and frost.
- If the base has sharp differences in height. In this situation, ordinary leveling compounds will not be able to cope with the task.
- To reduce the weight of the screed. The margin of safety of floor slabs is limited, especially for wooden slab overlap. Therefore, it is required to lighten the weight of the structure - the base is simply not designed to create a thick screed using the leveling mixture alone. Thus, it is customary to introduce additives into it, which are insulation - expanded clay and even foam.
- When the budget is limited and you want to save on cement.
- Prepare building level and marker.
- Outline at what level the finishing floor will be located. Usually this line coincides with the lower edge of the door frame. Therefore, the marks should be located near the doorway, then mark the entire room with a cord.
- To outline the line of the screed, step back from the already drawn line down to the distance of the thickness of the floor. Take the rope and, as in the previous case, mark the room.
- The granules are poured in an even layer, starting from the area where the screed should have a maximum thickness, moving throughout the room. The backfill should not reach the lower edge of the lighthouse by at least a couple of centimeters.
- In order for expanded clay to grab to the desired state, its layer should be shed with cement "milk" prepared from water and cement. At the same time, water is taken 3 times more than it should be according to the proportions for a conventional screed. The film that will appear later will become a barrier to moisture so that it is not absorbed into the expanded clay during the pouring of the mixture.
- After covering the entire area with “milk”, you will have to wait a day for the mixture to harden.
- The screed is poured after 24 hours. Start working from the wall, which is the opposite door. Then it is stretched to the sides. In this case, the rule is used that has the shape of a trapezoid.
- Make sure that no beacons peek out from under the layer.
- When you fill the entire room, leave the screed to dry. In terms of time, this is at least 1 week, and preferably 2-3.
- At the same time, it is recommended to spray the floor with water every day so that the screed becomes more durable. Plus, it will catch on faster.
- Prepare the mixture for the first layer with the addition of expanded clay crumbs. To do this, fill the container with water, pour the granules into it and mix thoroughly. Remember that moisture must be absorbed into them.
- Pour sand and cement into the container, mixing the solution using a construction mixer.
- Lay the resulting solution on a previously prepared floor surface, tamping and leveling with a trowel.
- The need to use cement milk is eliminated.
- Choose any width of the first layer for the convenience of pouring the finishing layer.
- Then you need to arm yourself with the rule and pull the mixture over several times to eliminate puddles and bubbles. If even small puddles are not removed, after they dry, pits will appear, which are eliminated only when the floor is refilled.
- When preparing a screed for the finishing layer, it is recommended to use a special liquid, which acts as a plasticizer and prevents the surface from cracking.
- If the budget is limited, and you do not intend to spend extra money, then fill in the screed without a plasticizer. In this case, it is necessary to constantly moisten the floor, but carefully so that cracks do not form.
