How to make a warm water floor on the ground. How to make a warm floor in a house on the ground

Any owner of a private house faced the problem of heating. Floors are a particularly important heating element. The right floors do not let dampness into the house and keep it warm for a long time. Recently, floors on the ground are rapidly gaining popularity.

They are effective because they are practical, reliable and relatively inexpensive. If a basement is not planned during construction, then on the ground in a private house is one of the best options for thermal insulation.

Such a design is built directly on the ground, taking into account all its irregularities and will help prevent cold from entering from its surface. This option is far from the easiest, but it can be implemented independently, without hiring workers or equipment.

Such floors have nothing to do with baking. They are called "pies" due to the fact that their thermal insulation has many layers and in appearance they slightly resemble a layer cake. If you still decide to build, then keep in mind that underfloor heating on the ground requires some measurements.

For example, groundwater should not be too high, because this will make your "pie" float. You should also make sure that the soil is strong enough, because the whole structure can simply settle. It should also be remembered that the “pie” reduces the height of the room, and the dismantling of such a structure is a difficult matter, so everything must be done correctly the first time.

Foundation preparation

The device of your structure includes several layers, and therefore several stages too.

Don't move on to the next step until you've completed the previous one.

The first thing we must do is to prepare the base directly on the ground itself. For this you need:

• remove the layer of earth. This must be done without fail, because the fertile layer is usually loose, and the remains of vegetation can then begin to rot and decompose - this will cause an unpleasant smell, and it will be impossible to be in the room. The floor cake requires about 20 centimeters, or even more (depending on the region).

• Tip: measure each level and calculate how deep you need to remove the soil. Leave marks on each of the levels to make it easier to navigate;

• remove all rubbish and stones. This is also very important, because one unnoticed pebble can cause unevenness;
• the remaining clean soil is leveled and compacted. This must be done very evenly - along the level.

Separating layer

To prevent anything from moving apart, the foundation of the pit must be lined with geotextiles or dornite. It is better to choose the first, because it also protects against the germination of weeds.

The correct underfloor heating cake must be separated from the parts of the foundation and the basement (the lower part of the building wall lying on the foundation) with a special layer. It is strictly forbidden to rest the plate on the protruding parts of the structure.

The correct floor should be made in the form of a floating screed.

Underlayment

Further, some variation is allowed. So that the floors on the ground do not settle down the correct cake, there are several options for laying. The underlying layer must be selected taking into account the height of the groundwater, the expected loads, the same looseness of the soil, and so on.

Most often, a concrete layer is used - this is the most reliable and proven option. But there are cases when it is impossible to use concrete, then the following materials can be used:

• sand. It is used exclusively on dry soils to avoid water absorption through small holes in the sand. It is noteworthy that such a process can occur even in cases where dew forms on the surface. It will also be more difficult with sand because it needs to be perfectly evenly compacted, again, this must be done with the help of a level;
• rubble. Crushed stone works well at high groundwater levels. In a layer of crushed stone, capillary absorption is completely impossible. Laying should also occur evenly;
• natural soil. It is used quite rarely and is, most often, coarse sand or gravelly soil (soil with a grain content larger than 2 mm, but less than 50 mm). It will fit if neither groundwater nor special looseness of the soil is observed.
• expanded clay. Also suitable.

Mineral wool boards (thermal insulation material made from mineral wool and a synthetic binder) will be an excellent insulation. They have a high density, are quite strong and live for a long time. Such plates are laid in two layers, they can be vulnerable to moisture, so they need to be treated with a water-repellent substance.

Footing

Whatever bonding material you use, you will still need a footing. You will need B 7.5 lean concrete mix. We remind you that lean concrete is concrete in which the content of cement and water is reduced, and the content of filler is increased.

Such material is much “weaker” than its “fat” counterpart, but at the same time cheaper. In our case, it is impractical to use a stronger concrete composition.

The footing is not reinforced, but must be separated from the basement or parts of the foundation. For this, pieces of foam or a special tape are suitable.

If you want to further reduce the cost of the floor cake on the ground, then you can use the saturation of the upper layers of crushed stone with cement milk. The resulting crust should be perfectly even, and its depth should be several centimeters. This trick will help make a waterproof concrete crust.

Waterproofing and insulation

Finally, we got to waterproofing and insulation. At this stage, it is necessary to isolate from moisture. We will do this with a waterproofing film or a special membrane. Lay the film overlapping, and seal the gaps at the joints with construction tape.

The first thing you need to put is waterproofing material, and not thermal insulation.

As a heater, use a layer of expanded polystyrene foam or dense polystyrene. You can also use special plates, but we advise you to do this only if the load on the surface of the structure is large.

You can choose the thickness of the layer yourself, depending on the climatic conditions of the region, usually it is from 5 to 20 centimeters. Joints and cracks fill with construction foam.

On top of the resulting "sandwich" lay another layer of waterproofing material or just roofing material. This is optional, but if you live in a humid region with high groundwater, it's best to play it safe.

damper layer

Lay a damper tape over the walls, which will be slightly higher than the planned thickness of the screed. This is necessary in order to isolate the future screed from the bearing elements of the foundation or basement.

We remind you: the floor on the ground of the cake is strictly forbidden to be rigidly connected with the elements of the base.

Instead of tape, you can use strips of polystyrene foam, which also needs to be laid a little higher. Excess pieces can then be cut off.

floating screed

Such a screed performs several functions at once: it produces thermal insulation and sound insulation at the same time. The design feature of this screed is that the solution is placed on the surface of the insulation, and not on the base.

Well, or on a layer of roofing felt, if you covered the insulation with it from above. Here's what to look out for:

• it is desirable to do everything at once. In large rooms, this will not be possible, so separate the finished and unfinished areas with partitions. This will create an expansion joint and help the screed to subsequently take on completely;
• if possible, pour over plaster beacons;
• the thickness of the screed should not exceed 20 centimeters, the minimum should not be less than 5. Be guided by the expected operational loads and the type of future flooring.

Reinforcement of the floor on the ground

Reinforcement is an important step that will help strengthen the concrete screed. The metal mesh will also serve to fix the pipes on it.

The reinforcing mesh should be a wire with square cells with a thickness of 5 to 10 centimeters. Depending on the design features, the thickness may vary.

The grid laying is as follows:

• a protective layer is laid from below - a polymeric material. The thickness of this layer should not exceed 1.5 - 3 centimeters.
• grid installation;
• installation of special beacons (in small rooms this is not necessary);
• pouring the mixture.

Walking on a non-hardened mixture is not advisable; it is better to install special paths along which you will move. Even when the mixture is taken, it is better to continue walking along these paths anyway, metal meshes have a much lower density and can bend under the weight of a person.

Stiffening ribs under partitions

In order for the cake of a warm water floor to hold better, it must be strengthened. This is done by stiffening ribs. To create them, it is laid under the partitions - a material that consists entirely of closed small cells.

The material must be laid intermittently, and the resulting voids should be used for laying the reinforcement. Thus, it should turn out that the entire structure is evenly reinforced with reinforcing bars.

Underfloor heating contours

For even greater savings in a warm floor on the ground, you can install it, this will allow you to create a literally warm floor. The reinforced mesh has just the right dimensions for placing a heating pipe on it.

To connect to the collectors, pipes are brought out near the walls. The walls must be pasted over with a protective tape. As for all other communications, they need a similar system.

After the final filling of the "pie" everything will be ready. Then you are free to do the floor the way you want. This design is just one of the possible options, if you wish, you can modify any of its elements. It all depends on your finances and construction conditions.

Video: underfloor heating cake on the ground

Arrangement of the floor is one of the most important points in the repair or construction. And if we are talking about a private house, this issue becomes even more acute. In many house projects, floors are often designed on the ground, this is quite reliable and one of the most practical and inexpensive options. Currently, underfloor heating is becoming more and more popular every day, so many people prefer this particular type of heating in the house. Reliable thermal insulation of the floor will provide warmth and comfort in it, as well as significantly reduce the cost of its maintenance. After all, warm floors perfectly retain heat in the house, create comfortable living conditions, and in some cases replace central heating.

What is a floor heating cake on the ground

Arranging floors on the ground, the obligatory moment is their thermal insulation, thanks to this, a multilayer structure is obtained, which is often called a warm floor cake. This design is in many ways reminiscent of a layer cake, as it consists of several layers. I would like to say that the construction of the floor on the ground largely depends on the condition of the soil. It must meet certain requirements. For example, the groundwater level should be at a depth of 5-6 meters, soils should not be loose, for example, sandy or black earth. In addition, it is necessary take into account the load on the floor. It should be noted that the warm floor cake should provide:

• thermal insulation of the room;
• groundwater protection;
• soundproofing in the house;
• prevent the accumulation of water vapor inside the floor;
• provide comfortable living conditions.

What does a floor heating pie consist of on the ground

By its design, the floor heating cake on the ground consists of several layers, the laying of each layer occurs in stages.

Depending on the design features of the floor and some other important factors, the floor heating cake on the ground may have a different composition and different thickness.

Advantages and disadvantages of underfloor heating on the ground

Advantages:

Flaws:

• underfloor heating, depending on the design features, can significantly reduce room height;
• in the event of a malfunction of this system, it is very difficult and expensive to dismantle the layers of the floor;
• sometimes it rather lengthy and complicated procedure, which is desirable to perform during the construction of the house;
• need to take into account groundwater position.

Options for laying a warm floor cake

There are several options for laying a warm floor cake on the ground. This may depend on the level of groundwater penetration, operational loads on the floor, type of underfloor heating and some other factors. The above option can be considered the main one, where as the main underlying layer is concrete layer. The cake is also laid in another way, where the concrete layer is replaced by a sand cushion, its thickness is 100-150 mm. The sequence is the same, although it is much more difficult to ensure an even base than with a concrete screed.

Depending on the thermal insulation materials, there may also be various options for underfloor heating cake. Choosing as a heater polystyrene foam, the laying of the pie will be as follows:

Excellent insulation - mineral wool boards, which have high density, resistant to deformation and durable. This material is recommended to be applied in two layers. For less moisture absorption, they are treated with a water-repellent composition. Used as an insulating layer in a warm floor cake and expanded clay. This is a fairly simple and inexpensive option. When laying the cake using expanded clay, as a heater, you can not lay additional waterproofing, also expanded clay replaces a layer of gravel and screed. There are some more pretty effective ways to lay a warm floor cake using some other heat-insulating materials.

Underfloor heating pie installation technology

Installed floors on the ground - this is one of the most successful options that reduces construction costs saves time and labor costs. A well-equipped floor heating pie will provide warmth, comfort and coziness in the house for many years.

Outwardly similar to the slab foundation, the floor construction on the ground is less massive and cheaper to manufacture. Instead of two reinforcing meshes, one wire mesh is used, stiffeners are needed only under heavy partitions. The floor on the ground is not a load-bearing structure, it is created exclusively for the installation of floor coverings.

Layered scheme of the floor on the ground.

The classic scheme of a concrete floor on the ground includes a correct and complete cake of several layers with insulation:

• sand;
• geotextile;
• crushed stone layer 0.4 m;
• footing;
• waterproofing;
• insulation;
• concrete screed with wire mesh in its lower third, separated from the basement, grillage or foundation by a damper tape around the perimeter.

Depending on the layout of the building, soil conditions and compliance with technology, the composition of the floor on the ground may vary. For example, on coarse sandy soil, sand and geotextiles are not needed.

The footing can be replaced with a leveling layer of sand on top of the rubble. To reduce the construction budget, foundations are often not poured under partitions, so stiffening ribs reinforced with reinforcing cages appear in the floors along the ground. In any case, before starting the production of a floating screed, it is necessary to prepare the existing base and plan it in a single horizontal level.

Foundation preparation

Despite the fact that concrete is the most durable structural material, swelling of the soil and subsidence of the base are dangerous for the screed. Therefore, the arable layer in the building spot should be completely removed: black soil or gray soil is saturated with organic matter, which will rot, after which the whole cake will sag, and, unevenly in some areas, cracks will open in the screed or the concrete floor will be destroyed along the ground.

For communications, it is necessary to dig trenches with a slope, bring them outside the foundation and near the walls inside the house.

Distribution of engineering systems.

Important! The correct floor on the ground is made in the form of a floating screed, separated from the foundation elements and plinths by a damper layer. It is forbidden to rest the slab on the protruding parts of these structures.

Separating layer

In order to avoid mutual mixing of the layers of the floor cake on the ground with the base soil, the pit is lined with non-woven material (geotextile or dornite). The edges of the separating layer web are launched onto the side surface and pressed with bricks, wall blocks. An additional function of geotextiles is to prevent the germination of weed roots through the concrete floor along the ground during operation.

Advice! Under the floating screed, geotextiles with a density of 100 g/m 2 or more can be laid, since the construction is considered not responsible, unlike slab foundations, which require needle-punched material with a density of 200 g/m 2 or more.

Underlayment

The concrete floor pie on the ground must rest on a hard layer to avoid subsidence of the soil. Therefore, depending on the soil conditions, non-metallic materials are used:

Less commonly used natural soil (coarse sand or gravel soil). If the developer has expanded clay after the dismantling of the building or this material is cheaper in the region than crushed stone, this material is also suitable as an underlying layer.

Advice! A prerequisite is high-quality compaction of every 15 cm of the underlying layer with a vibrating plate or manual rammer. Spilling sand with water is not recommended, the material should be moistened from a watering can before backfilling and compaction.

Footing

The classic floor pie on concrete soil includes a screed-concrete from a lean mixture of B7.5. It is necessary to solve several problems:

However, to reduce the construction budget, the footing is replaced with other technologies:

Important! The footing is not reinforced, but is necessarily separated from the elements of the foundation or base along the perimeter with a damper layer (pieces of expanded polystyrene on the edge or a special tape).

Waterproofing and insulation

At the next stage, the cake must be isolated from moisture, to prevent heat loss in the floors and to keep the geothermal heat under the building. For this, waterproofing and insulation are used. Their relative position inside the design pie is as follows:

The main mistake of developers is laying vapor barrier over polystyrene foam:

• the air temperature in the room is always higher than in the soil under the screed (valid for heated rooms);
• therefore, when laying a floor covering that does not have vapor barrier properties (flooring board, parquet, cork), the steam direction will always be from top to bottom;
• the vapor barrier membrane will accumulate moisture on the surface, inside the cake, at the insulation / concrete border;
• the screed will collapse and the wire mesh inside it will corrode.

In addition to an unreasonable increase in the construction budget, this scheme does not provide any advantages. The accumulation of harmful gas - radon under the floors on the ground is impossible, since there is no underground in this design.

The following materials can be used as waterproofing:

• built-up roll - TechnoNIKOL, Gidrostekloizol, Bikrost or roofing material;
• film - made of polyvinyl chloride or polyethylene;
• membranes - have a high density and strength, can be laid without making footings.

• Admix mixture - an additive is added to concrete during mixing, the structural material becomes waterproof;
• Penetron - the floor on the ground is processed AFTER concreting, the effect is similar to the previous one.

For these waterproofing materials, footing is also not needed.

Of all the existing heaters, the best option for flooring on the ground is high-density extruded polystyrene foam grades XPS or XPS (for example, Penoplex). The thickness of the layer depends on the climate of the region of operation, it is 5 - 20 cm. The sheets are laid with mixing joints in adjacent rows, large gaps are filled with mounting foam of similar properties.

damper layer

Floors on the ground must not be rigidly connected to the elements of the basement or foundation, therefore, along the perimeter, it is necessary to install strips of polystyrene foam on the edge, pressing them to the vertical enclosing structures. However, more often a special damper tape made of latex, rubber or foamed polymers with an adhesive layer is glued to the walls.

Important! The height of the cutting layer should be slightly higher than the thickness of the floating screed. After the concrete has hardened, the material is cut off with a knife, the junctions are decorated with a plinth after laying the floor covering.

floating screed

The main nuances of concreting the floor on the ground are:

• it is recommended to fill in one step;
• plots larger than 50 m 2 (relevant for studio rooms, sheds and garages) should be separated by a special corner to create expansion joints;
• internal load-bearing walls and heavy partitions should be erected on a separate foundation;
• partitions from GKL / GVL must be erected partially so that when the screed dries, the moisture is not absorbed into the drywall or gypsum fiber sheet, destroying these materials;
• it is preferable to fill on plaster beacons or profiles for GKL systems installed at a single horizontal level on quick-drying putty mortars;
• screed thickness 5 - 20 cm, depending on the operational loads and the planned floor covering, as well as the need to install underfloor heating pipes.

Partial construction of plasterboard partitions is carried out according to the technology:

• installation of racks and horizontal jumpers;
• sheathing them at the junctions of the floor along the ground with plasterboard strips 10–20 cm high along the entire length.

For the floor on the ground, you can use ready-mixed concrete B12.5 and higher, the filler is gravel, dolomite or crushed granite. The screed is reinforced at the lower level with wire mesh.

Important! If the technology is broken, heavy partitions are planned to be supported on a screed, in places where they pass, stiffeners are needed, which are created by analogy with the UShP slab (insulated Swedish foundation floating slab).

Reinforcement of the floor on the ground

The industry produces VR welded wire mesh according to GOST 8478 from 5 mm wire with a square cell of 10 - 20 cm. Self-knitting on site is more expensive due to the high consumption of knitting wire and increased labor intensity. Grids are laid according to the technology:

Unlike reinforcing mesh, wire cards have a much lower rigidity; walking on them when laying the mixture is strictly prohibited. Therefore, the following methods are applied:

• ladders - halves of bricks are laid in the cells of the grid, on which the boards are supported, moved along with the gaskets as the structure is ready;
• "paths" - concrete piles up from the entrance of the room to the far corner, after which, you can walk along these paths without shifting the grid.

Smaller rooms usually use appropriately sized grid cards. If the room has a complex configuration, it is necessary to cut additional pieces. In this case, and when reinforcing large areas, the overlap of cards / rolls is at least one cell.

Stiffening ribs under partitions

To create stiffening ribs under the partitions, intermittent laying of extruded polystyrene foam or its top layer is used. Reinforcing cages made of square clamps (smooth reinforcement 4–6 mm) and longitudinal rods (“grooved” 8–12 mm) are placed in the voids formed.

Underfloor heating contours

Underfloor heating is used to reduce energy consumption in the heating boiler and increase living comfort. Their contours can be built into the screed by laying the pipes directly on the reinforcing mesh.

To connect to the collectors, the underfloor heating pipes are brought out near the wall. In this place they must be pasted over with a damper tape. A similar expansion joint technology is required for all communications passing through the screed (heating risers, hot water / cold water).

Thus, the composition of the floor on the ground can be modified depending on the construction budget and specific operational and soil conditions.

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The arrangement of a warm floor in a house on the ground requires a carefully planned approach. In most cases, phased work is required: at the first stage, a rough screed is poured and waiting for it to mature, at the second stage, the remaining layers are laid.

Design for a private house

Neglect of this rule can lead to negative consequences. This is explained by the constant movement of the soil and, accordingly, all the layers located above. Movements can be observed even on compacted and compacted soil, which has been unloaded for a long time.

After laying the underfloor heating cake, which has a rather impressive mass, cracks from subsidence may form. The most negative consequence may be a rush of elements of the warm floor, that is, all the costs of its arrangement will be in vain.

The device of a warm water floor on the ground

At the first stage, it is necessary to determine the level to which excavation will be carried out. It is necessary to remove the upper fertile layer in any case, since plant residues tend to decompose and smell unpleasant. Regardless of whether the subfloor is poured or not, the top layer of soil must be removed.

In addition, the fertile layer is less dense due to the presence of living beings and microorganisms in it, therefore, under the weight of the layers of a water-heated floor, it will begin to sag. As a result, the overlying layers will again suffer.

The height of the floor heating cake on the ground can be more than 20 cm, so the countdown must start from the mark where the finishing floor will pass. In this place put the appropriate mark and count the required depth. In this case, it is better to mark the level of each layer, so that it is easier to navigate in the process of arrangement.

Walkthrough

For the qualitative implementation of the process, it is necessary to strictly follow the rules for installing a warm floor on the ground:

• Remove the upper fertile layer, remove large debris and stones. Level and tamp the bottom of the resulting pit. This will be the basis for the layers to be laid, so the level is best checked with a level.
• Next, a layer of sand is poured, and any sand is suitable for filling. It must be well tamped and leveled.
• The next layer in the composition of a warm floor with water heating is expanded clay or crushed stone. However, it should be remembered that crushed stone is characterized by lower thermal conductivity. It is better to take stones of small or medium size. It is necessary to compact for a long time until the surface becomes almost monolithic.
• Now it's the turn of the preliminary screed, for the manufacture of which you can use two options. In the first case, sand and gravel are shed with a liquid solution of sand and cement in a ratio of 2: 1. In the second case, a rough screed 5-7 cm thick is poured with a reinforcing mesh laid. This option is considered more reliable, able to withstand significant loads.
• After setting the screed and hardening of the concrete solution, they proceed to laying the waterproofing layer. In most cases, a 200 micron thick polyethylene film is used for this, laid in two layers.
• Expanded polystyrene plates are laid on the waterproofing, the joints must be glued with adhesive tape to prevent the solution from leaking.
• From above it is necessary to lay a metallized waterproofing.
• Then proceed to the installation of the "warm floor" system. Install fasteners, lay the cable and heating tubes.
• The entire structure of the underfloor heating on the ground is poured with a reinforced underfloor screed.

Before you make a warm floor in a private house, you need to take into account all the nuances. The thickness of each layer is determined by the climatic conditions of the region, for colder areas thick layers of the cake are required, for the southern regions the layers can have a thickness of 2 to 5 cm. Careful compaction and alignment of the layers is the key to a better and more durable underfloor heating. For tamping layers of underfloor heating on the ground with your own hands, you can use manual devices, however, a mechanized process allows you to achieve maximum efficiency.

Thermal insulation material deserves special attention. When deciding how to make a warm floor on the ground, it is recommended to use expanded polystyrene plates with a density above 35 kg / m 3. The thickness of the heat-insulating layer is also determined by the climatic conditions of the area. In the northern regions, thermal insulation is laid with a thickness of 10 cm or more. At the same time, laying can be carried out in two layers with overlapping of the seams of the lower row with upper plates. The joints of the plates must be glued with adhesive tape.

A rather important point in the scheme for arranging a water-heated floor is waterproofing and thermal insulation of the foundation. It is supposed to treat the base surface with a waterproofing material before the start of all work. In addition, it is recommended to lay polystyrene foam plates around the perimeter, which will become an obstacle to the path of cold air inside.

How to make a warm floor on the ground with a high level of groundwater

With a high level of groundwater, it is necessary not only to correctly position the layers of the warm floor. It is very important at the same time to organize the diversion of water from the foundation.

For floors on the ground with a warm water floor, the level of which is located below the passage of groundwater, it is necessary to equip drainage. In this case, at least 30 cm below the floor level, a drainage system is made. River sand or loose soil mixed with crushed stone is poured at the bottom.

The material is poured in layers no more than 10 cm, each layer is abundantly moistened with water and carefully compacted. In most cases, three layers are enough, but you can add more if necessary. A geological textile is laid on top of the sand or soil, which prevents the penetration of water to the layers of the warm floor. Geotextile is a modern material characterized by high tensile strength and resistance to damage by rodents. In addition, it is able to compensate for the mechanical loads that will be exerted on the warm floor on the ground in a private house.

Features of the floor layer scheme

Also, one should not forget about the foundation, it can be treated with bituminous mastic or other waterproofing materials and impregnations. For thermal insulation, polystyrene foam boards are laid along the inner perimeter.

Then they act according to the scheme of the usual installation of a water-heated floor on the ground. Layers of sand and gravel fall asleep and a rough screed is poured. In this case, it is better not to use the option with a liquid solution of sand and cement. A reinforced rough screed is considered more reliable.

For waterproofing at a high location of groundwater, it is recommended to replace the polyethylene film with built-up waterproof materials or polymer membranes. The cost of these materials is higher, but the reliability and quality are at a high level.

Then, the heat-insulating material and the metallized hydrobarrier are laid. The "warm floor" system is mounted according to the instructions. A metal reinforcing mesh is laid on top and the entire structure is poured with a concrete screed.

The completion of all work is the installation of the final floor covering.

A warm floor on the ground can be called a complex structure, the arrangement of which must be approached very responsibly. For greater reliability, a rough screed should be poured, in extreme cases, all layers should be carefully tamped.

Your question, it almost always arises when installing both a simple floor and a warm floor on the ground. The question is basically whether it is possible to lay waterproofing and all subsequent layers (epps, etc.) on the backfill, or necessarily on the subfloor. Look, a lot of opinions for what is possible. But here we thought for a long time, and consulted, and came to the conclusion that it is still better to lay the waterproofing (and subsequent layers) either on a rough screed, or to perform a spill, and on it. Let me explain what we are based on. You have soil inside the box, although it was caked, but it just lay, without load. Now you will add more layers, and they are also not hard, but bulk. That is, the waterproofing will be between the hard eps and the bulk (albeit rammed) layer. Any movement of the layer under the waterproofing will cause the waterproofing to be somehow unevenly located. Following micromovements of waterproofing, there may be micromovements of eps. I understand that all your top ties will be reinforced, and they will "keep" the ties from moving. But still, why these extra loads? And I can not guarantee that nothing will ever move in the layers under the waterproofing :-).

By the way, you have waterproofing in the text description, but not in the picture. If your groundwater is lower than 2 meters from the floor mark, then there may not be waterproofing. Just put eps and so on. But everything I wrote above is still valid. Without a rigid layer under the eps, any movement under it will create additional loads on the upper layers.

• sand filling 50mm thick, level
• backfilling of crushed stone or expanded clay with a thickness of 100 mm, and on it, or pouring a layer of crushed stone / expanded clay with a liquid cement-sand mortar ((2 parts of sand per 1 part of cement), or a rough screed. In total, the thickness of the crushed stone / expanded clay already spilled with a solution will be 10-12 cm. If this spill is not done, then a rough screed of 5-7 cm should be made on top of the expanded clay. Let the solution harden and lay the waterproofing and subsequent layers on top of it.
• waterproofing
• laying blocks of expanded polystyrene, a layer of 50mm blocks, 20mm blocks on it, so that the total is 70mm
• top waterproofing with foil
• fittings and pipes for underfloor heating, poured into a concrete screed 100 mm thick
• topcoat (tile), about 20mm on it.

As for the fact that the upper 100 mm of soil must be removed for the crushed stone dumping device, this requirement, apparently, in order to arrange the dumping on better packed layers (not on the surface). You can do this, it will only benefit.