Recommendations for the installation of a water heated floor on the ground. Water heated floor on sand

The installation of a warm floor in itself is considered a complex engineering task. If the floor is in direct contact with the ground and serves as part of a liquid heating system, the likelihood of making a mistake increases significantly. Today we will talk about both the materials used and the phased device.

Laying a warm floor on the ground refers to complex engineering measures. This means that the contractor is responsible not only for the efficiency and long service life of the heating system, but also for the normal behavior floor covering under cyclic heating conditions. Therefore, act consistently and strictly follow the device technology recommendations.

Which pipes are suitable for underfloor heating

The first thing to do is to decide on the type of heat-conducting tubes. While the issue of acquisition desired type products, you will have time to carry out all the necessary preparatory work. In addition, you will know from the outset the system for fixing the pipes, and you will provide everything necessary for this.

So, let's start with the rejection of pipes that do not have such a purpose as use in underfloor heating systems. Here we include metal-plastic polyethylene pipes connected by a system of press fittings and PPR pipes for soldering plastic plumbing. The former do not perform well in terms of reliability, the latter do not conduct heat well and have high coefficients of thermal expansion.

Initially, a convenient and reliable mounting system for temporary pipe fastening is selected. It can also be a reinforcing mesh, to which the pipes will be tied with wire, but imagine installing in this way on an area of 100 m 2 or if suddenly several ties come off during the pouring of concrete. Therefore, a mounting underlay or rail system must be used. They are attached to the floor base while the pipes are not yet laid, then the pipes are fixed in the guides with clips or click-clamps.

The mounting system itself can be plastic or metal. There is not much difference in this, the only thing you need to pay attention to is how reliable the fixation is and whether the guides themselves can damage the pipes.

Finally, we decide on the material of the pipes. There are two types of products recommended for use in underfloor heating systems. For both, the mounting technology eliminates the influence of the human factor when bending and connecting.

Copper. Despite the increased cost, copper tubing is easy to install, soldering requires a bottle of flux and gas-burner. Copper the best way manifests itself in systems of "fast" underfloor heating, which works in parallel with radiators, but not on an ongoing basis. bend copper tubes are carried out according to the template, respectively, their break is extremely unlikely.

Polyethylene. This is a more common class of pipes. Polyethylene is practically not subject to fracture, but a special crimping tool is required for installation. Polyethylene can have different density, it is recommended not less than 70%. The presence of an internal oxygen barrier is also important: polyethylene poorly resists diffuse penetration of gases, while water in a pipe of this length can entrain significant amounts of oxygen from the external environment.

Soil preparation

When installing a warm floor on the ground, a “pie” is prepared, the thickness and filling of which are determined in individually. But these data are important already at the first stage of work, in order to deepen the earthen floor if necessary and not sacrifice the height of the room.

In general, the soil is removed 30-35 cm below the level of the planned floor covering, taken as the zero point. The surface is carefully leveled in a horizontal plane, the geotextile layer is backfilled with incompressible material, in most cases, PGS is used for this.

After careful manual tamping of the bedding, preparation is carried out with low-grade concrete. For additional thermal insulation, this layer may consist of lightweight expanded clay concrete. It is important that the surface is displayed in common plane, located below the zero mark by the thickness of the cake plus about 10-15 mm more.

The choice of insulation

A floor pie with water heating consists of a heater tightly sandwiched between two layers of cement-sand screed. A fairly narrow range of requirements is imposed on the insulation itself.

Mainly compressive strength is normalized. Extruded polystyrene foam with a density of 3% or more is ideal, as well as PIR and PUR boards as more fireproof. If desired, you can use mineral wool slabs of grade 225 according to GOST 9573-96. Cotton wool is often abandoned due to the complexity of its installation and the need to cover the insulation with a hydrobarrier (polyamide film). It is characteristic that minimum thickness the plate is 40 mm, while when installing a reflective screen made of XPS, the thickness of the latter rarely exceeds 20-25 mm.

Foam polymer materials also serve as a good barrier to moisture migrating from the soil; they do not require a waterproofing device. Many may be put off by the questionable safety of styrene-containing material or the price of more expensive boards with complete chemical inertness (PUR and PIR).

The thickness of the insulation is determined thermotechnical calculation. If the preparation used concrete with expanded clay as a filler, 10-15 mm XPS or 60 mm mineral wool will be sufficient. In the absence of insulated preparation, these values \u200b\u200bshould be increased by 50%.

Preparatory and accumulating screeds

It is very important that the insulation is tightly clamped between two ties and that any movement or vibration of it is excluded. The concrete preparation of the floor is leveled with a preparatory screed, then insulation boards are glued onto it using tile adhesive under the comb. All joints are sealed with glue. If used mineral wool, concrete preparation must first be covered with a layer of penetrating waterproofing.

The screed layer above the insulation must be so thick that its total thermal conductivity is at least 3-4 times lower than that of the thermal screen. In general, the thickness of the screed is about 1.5-2 cm from the final height of the ceilings, but you can freely “play” with this value to adjust the inertia of the warm floor. The main thing is to change the thickness of the insulation accordingly.

The top layer of the screed, subjected to heating, is poured after the walls are enclosed with a damper tape. The filling of the accumulative screed can, for convenience, be carried out in two stages. On the first one, about 15-20 mm are poured with reinforcement with a rare mesh. It is convenient to move along the resulting plane and fix the pipe installation system, the remainder is poured to the zero level minus the thickness of the floor covering.

1 - compacted soil; 2 - sand and gravel bedding; 3 - preparatory reinforced screed; 4 - hydrovapor barrier; 5 - insulation; 6 - reinforcing mesh; 7 - floor heating pipes; eight - cement-sand screed; 9 - flooring; 10 - damper tape

System installation, proportions and loop pitch

The laying of underfloor heating pipes should be carried out according to a scheme previously thought out and drawn on the floor. If the room has a shape other than rectangular, its plan is divided into several rectangles, each of which is represented by a separate loop loop.

The same principle applies to floor zoning. For example, in the play area, tubes can be laid at a more frequent pace, and it is advisable not to lay them under cabinet furniture at all. In each individual coil of a rectangular shape, depending on the priority of heating, the tubes can be laid either in a snake or a snail, or a combination of options. General rule simple: the farther a specific point is from the beginning of the duct, the lower its temperature, on average, there is a drop of 1.5-2.5 ºС every 10 meters, respectively, optimal length loop is in the range of 50-80 meters.

The minimum distance between adjacent tubes is determined by the manufacturer according to the allowable bending radius. A denser gasket is possible according to the “snail” scheme or with the formation of wide loops at the edges of the snake. It is optimal to adhere to a distance equal to 20-30 values of the tube diameter. You also need to make allowances for the thickness of the storage screed and the desired floor heating rate.

The mounting system is attached along the route of laying through the insulation to the layer concrete preparation, respectively, the length of fasteners (usually plastic BM dowels) should be 50% more than the distance to the surface of the preparatory screed.

When laying the pipe, you should consider an improvised spool for unwinding, otherwise the pipe will constantly twist and break. When all the hinges are fixed in the mounting system, they are checked high pressure and, if the test results are satisfactory, pour upper layer accumulating screed.

Inclusion of a warm floor in the heating system

It is recommended to lay whole pipe sections without joints in the screed layer. The tails of the loops can be reduced either to local collectors, or lead directly to the boiler room. The latter option is usually convenient when the heated floor is slightly removed from the boiler or if all rooms have common corridor, for which indirect heating is sufficient.

The ends of the pipes are rolled with an expander and connected by crimping or soldering with threaded fittings for connection to a manifold assembly. Each of the outlets is equipped with shut-off valves, ball valves with a red flywheel are installed on the supply pipes, and with a blue one on the return. A threaded transition with shutoff valves is necessary for emergency shutdown of a separate loop, its purging or flushing.

An example of a scheme for connecting a water heated floor to a heating system: 1 - a heating boiler; 2 - expansion tank; 3 - security group; 4 - collector; 5 - circulation pump; 6 - manifold cabinet for heating radiators; 7 - manifold cabinet of underfloor heating

The collectors are connected to the heating main by analogy with heating radiators, two-pipe and combined switching schemes are possible. In addition to the thermostat, the collector units can be equipped with recirculation systems that maintain a comfortable temperature of the coolant in the supply at about 35-40 ºС.

A concrete floor on the ground in a private house is a long-known universal way of arranging a reliable and warm base. Through the use of new types of insulation, we get good thermal insulation the entire floor, which leads to a reduction in the cost of utilities. And also the insulation is an obstacle to the penetration of moisture and the appearance of fungus and mold.

And the most important thing is that this species you can build the floor with your own hands. In this article we will analyze all the advantages and disadvantages. Consider in detail the arrangement of the floor on the ground.

Floor on the ground: the pros and cons

Let's start with the fact that this type of floor is a "layer cake". And each layer has its own functions and purpose, thanks to such a device, the floor on the ground has a number of advantages:

There are not many disadvantages, but they are all there:

Cannot be used on loose ground.

How to make the right floor construction on the ground

We will consider the correct classic floor structure, which will consist of 9 layers. We will analyze each layer separately.

It’s worth saying right away that for each master and specialist, the number of layers can change, and the materials can also differ.

This type of flooring is ideal for tape type foundation. The average thickness of the “floor pie” is approximately 60-70 cm. This should be taken into account when building the foundation.

If you do not have enough foundation height, then select the soil, to a given depth. Level the surface and tamp. For convenience, in the corners around the entire perimeter, a scale should be applied in increments of 5 cm, so it will be more convenient to navigate in layers and levels.

It is important that for compacting the soil it is best to rent a vibrating plate, since manual way will take a lot of time and will not give such results as a special device.

Clay. If during the sampling of the earth you have reached a layer of clay, then you should not fill in a new one. The layer thickness must be at least 10 cm.

Clay is sold in bags, we pour it out and moisten it with a special solution (4 liters of water + 1 teaspoon liquid glass), and ramming is carried out using a vibrating plate. After tamping, we spill a layer of clay with cement milk (10 liters of water + 2 kg of cement).

We make sure that there are no puddles. As soon as you spill clay with this composition, the process of glass crystallization begins.

You should not do anything for a day, it is worth waiting for the crystallization process to seize, and it will end in about 14-16 days. This layer prevents the main flow of water from the ground.

Layer of waterproofing material. The purpose of this layer is to protect the insulation from moisture. You can use ruberoid, polymer-bitumen materials, PVC membranes and polyethylene film not less than 0.4 mm thick.

In the case of using roofing material, it is preferable to lay it in two layers, on liquid bitumen. Lay waterproofing overlap with each other and on the walls.

Between themselves 10-15 cm, and on the walls to the height of the floor level. The seams must be glued with construction tape. Walking on waterproofing material should be in soft shoes.

insulation+ layer of vapor barrier. Most best material for insulation, it is extruded polystyrene foam (EPS). For reference, EPPS 5 cm thick can replace a 70 cm layer of expanded clay.

But so, you can use perlite concrete and sawdust concrete. Insulation sheets are laid without joints, so that one plane is formed.

The thickness is determined depending on the region, the recommended thickness of the insulation is 5-10 cm. Some use mats 5 cm thick, and lay two layers, with offset seams, and glue the upper seams with special adhesive tape.

In order to remove cold bridges from the foundation or basement, the insulation is laid vertically and fastened with dowels with inside. Experts recommend insulating the basement from the outside, with one sheet of insulation and also fixing it with dowels.

On top of the insulation should be laid a layer of vapor barrier. As a vapor barrier material, it is best to use PVC membranes, they do not rot and have a long service life. The disadvantage of this material is the high cost.

The main task of the vapor barrier material is to protect the insulation from the harmful alkaline effects. concrete mortar. The material is laid with an overlap of 10-15 cm and glued with construction tape.

We make smoothing with the help of a rule or a vibrating screed. As soon as the solution dries, the beacons should be removed, and the cavities filled with a solution.

The entire concrete floor should be covered with a film and watered periodically. In a month, the concrete will gain full strength. To pour concrete with my own hands, I make a solution of the following composition: cement + river sand in a ratio of 1 to 3.

In the case of using underfloor heating technology, water or electric. Be sure to mount the rough floor screed on the ground.

After laying the insulation, pipes or wires are laid. Then we fill the cavities with concrete, lay the reinforcing elements and continue pouring concrete to a predetermined level.

The technology of floors on the ground can be used not only in brick and stone houses, but so, the same in houses made of wood. With the right approach and correct calculations, the layers do not harm the wooden elements.

Finish flooring. Received concrete surface suitable for any type of fine flooring. It all depends on your preferences and financial capabilities.

As mentioned above, the combination of components, and the number of layers may be different. It all depends on your finances and capabilities.

Conclusion

As we all know, from 20 to 30% of heat can go through the floor. In cases where there is no “warm floor” system, the floors should be as thermally insulated as possible, and this in turn increases the energy efficiency of the entire house.

The owner of a private house receives comfort, coziness and savings on utility bills. Floors on the ground with insulation are a highly effective and long-term choice for every owner.

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

Layered scheme of the floor on the ground.

AT classical scheme concrete floor on the ground laid the 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 soil of the base, the pit is lined nonwoven fabric(geotextile or dornite). The edges of the separating layer web run on side surface and pressed against a brick, wall blocks. Optional feature geotextile is to prevent the germination of weed roots through the concrete floor on 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 design is considered not responsible, in contrast to slab foundations, for which needle-punched material with a density of 200 g / m 2 or more is required.

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 existing heaters the best option for the floor 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 stacked with mixing joints in adjacent rows, big gaps are filled with polyurethane foam similar in 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;
domestic bearing walls and heavy partitions should be erected on a separate foundation;
partitions from GKL / GVL must be erected partially so that moisture, when the screed dries, 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. high flow 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.

AT small rooms grid maps are commonly used right size. 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. In the resulting voids fit reinforcing cages from square clamps (smooth reinforcement 4 - 6 mm) and longitudinal rods ("corrugated" 8 - 12 mm).

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. Similar technology expansion joint necessary 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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In your home, you may need a water heated floor on the ground. Subject to compliance with existing SNiP, you can do the work yourself, from backfilling to finishing screed, followed by flooring.

Is it possible to make a water floor on the ground

A pie of a water-heated floor on the ground can be performed provided that the method of installing a heating system using concrete screed. Laying allows you to simultaneously achieve several goals: to make a rough floor and prepare the base for the finish coating.

The design of a water heated floor on the ground provides for the work that is usually used for cooking concrete slab in industrial and residential buildings. The result of the work largely depends on the achievement of several tasks:

Providing reliable thermal insulation that prevents freezing of the floor.
Protection of the premises from the appearance of dampness.
Prevention of cracking of the slab after several years of operation.

Competent self-laying a water floor on the ground helps to complete all three tasks. Installation directly on the ground is allowed in accordance with SNiP.

What "pie" should be under the warm floor

The layout of the floor on the ground is somewhat different from the usual pie used to install the heating system on an already prepared base. The following stages of work are carried out:

To make a water floor on the ground with your own hands, it will take time from 20 days to 1.5 months. You can speed up the installation process by ordering ready-made cement mixtures.

The main mistakes when installing a water floor on the ground

When performing work on bulk soil, it is easy to make mistakes that lead to the destruction of the slab in the future. Requires strict adherence phased production floor water heating pie, starting from the ground.

It would be optimal to preliminarily perform a heat engineering calculation that allows you to accurately determine the thickness of the powder, thermal insulation and the power of the heating system.

Common mistakes during installation are:

Violations of the technology of installing a warm water floor on the ground. The absence of compensation gaps in the slab, poorly performed work on tamping the powder, improperly laid waterproofing, subsequently become the cause of freezing of the screed, accumulation of condensate and dampness in the room.
Be sure to sprinkle sand on the soil base before crushed stone. In this case, any type of raw material can be used, but coarse river sand will be optimal. The minimum soil density after compaction depends on the weather and atmospheric conditions of the area and is calculated according to special tables.

Independent installation of a water heating circuit on the ground is used in private houses, garages, car services and other buildings. Step-by-step observance of the laying rules will allow you to perform all the work yourself.

When planning to make a warm floor in the house on the ground, it is advisable to make the structure in two stages: first, pour a rough screed onto the lower layers, and only after it has matured, lay all the other layers on it.

The fact is that the soil and, accordingly, all layers above it can sag. Even if the soil is compacted, even if it is rammed, there will be movements. He lay simply, without load. If you lay a warm floor cake on top, and it weighs a lot, drawdowns will begin, cracks will appear. It can even break the elements of the warm floor. Then all the money will be thrown to the wind. That is why experts advise first to make a rough floor according to all the rules, and then lay a water floor on top. So much more reliable.

Yes, many have a warm floor on the ground without a screed, and nothing sags. But not for everyone and not always. So think carefully. A warm concrete floor on the ground will be more reliable with a rough screed. If you still decide to do without this layer, install at least two reinforcing frames: the first under the heat insulator, and the second in the screed. Then, with careful ramming, everything can stand well.

An example of a floor heating pie on the ground

First of all, we determine the level to which you need to remove the soil. The soil must be removed. If a layer of humus or plant remains do not remove, they will begin to decompose and "smell". Therefore, you will make a draft floor or not, but you need to remove all unnecessary. Moreover, the fertile layer is usually the loosest, and it will definitely settle and can pull all the layers lying above with it. The rocks lying below are denser, firstly because they experience heavy loads, and secondly, because living beings and microorganisms live there less.

For the whole cake of a warm floor on the ground, it can take from 20 cm or more (in some regions - much more). Therefore, you need to start marking with zero level- where you will have a finishing floor. Mark it, and then consider how deep you need to go. It is advisable to mark the level of each layer: then it will be easier to navigate.

Warm floor on the ground is quite possible to do it yourself

The correct design of a warm floor on the ground is as follows:

Take off fertile soil remove all rubbish and stones. Level and compact the remaining soil. This must be done very carefully, and verified by the level. This is the basis for all subsequent materials.
A layer of compacted sand (level). Any sand is taken for filling. The main thing is to compact it well and level it again.
A layer of expanded clay or crushed stone (crushed stone is preferable due to lower thermal conductivity). Fraction - small or medium. We compact for a long time and persistently until it becomes almost a monolith.
Pre-stretch. There are two options here:
- Spill crushed stone and sand with a liquid solution (sand + cement in a ratio of 2: 1).
- Fill in the black screed. The desired thickness of this layer is 5-7cm. And for reliability, lay a reinforcing mesh of metal wire 3 mm, with a cell of 10 * 10 cm. Such a subfloor is more reliable. It will withstand heavy loads.
After everything has set and the concrete has hardened, a layer of waterproofing is laid. If the primer is dry, this is usually a polyethylene film, preferably 200 mn in two coats.
Styrofoam plates (glue the joints with adhesive tape so that the solution does not leak).
A layer of metallized waterproofing (not foil, but metallized).
Underfloor heating fixing system and heating tubes, cables, etc.
Underfloor heating screed, preferably reinforced.

Read about solutions and additives for underfloor heating here.

The thickness of all layers of the underfloor heating cake on the ground depends on the region: the colder, the more. In the south, it can be 2-5 cm, but the further north, the more massive layers are required. Each of them is well compacted and leveled. You can use manual rammers, but mechanical ones are much more effective.

Particular attention should be paid to the heat insulator. It is recommended to use expanded polystyrene in plates, its density is not lower than 35 kg / m3. For northern regions it can be 10 cm or more. If the thickness of the thermal insulation is large (extruded polystyrene foam), it is advisable to use two layers of boards. And lay them so that the seams of the lower layer overlap with the slab lying on top. Glue the joints of each layer with tape.

To protect against dampness, do not forget to carry out all work before starting all work. waterproofing works with foundation. It is also important not to forget to isolate the foundation from the entire underfloor heating structure. It is necessary to put the same polystyrene foam in plates along the perimeter. In general, the idea behind hydro and thermal insulation is this: to reduce heat loss, you need to isolate your floor from everything but indoor air. Then the heating will be economical, and the rooms will be warm.

The choice of thermal insulation is a key moment in the organization of a warm floor

Process technology at high groundwater levels

If the groundwater is high, the correct sequence of layers is not everything. You need to get the water out somehow.

If the depth of laying the underfloor heating layers turned out to be lower than the level of soil water, drainage is necessary. For him, at least 30 cm below the required level, we make a system for draining water. It is advisable to pour river sand, but such volumes cost a lot, so you can use other rocks, but not peat or black soil. As an option - excavated soil mixed with crushed stone.

When laying thermal insulation boards their joints need to be glued with adhesive tape - so the solution will not flow into the gap

The selected material is poured in layers of 10 cm, each of which is compacted and spilled with water. Layers are usually made three, but more can be. On compacted sand or soil with crushed stone, we lay a layer of geotextile. it modern material, which will pass water down and will not mix different materials. It is not damaged by insects and animals, has high tensile strength. Also, geotextiles additionally equalize the mechanical loads that the floor will experience.

At the same stage, you need to take care of both the hydro and thermal insulation of the floor from the foundation. Can be used for this purpose bituminous mastic or other modern and reliable waterproofing materials and impregnations. And the thermal insulation is standard: the inner perimeter of the foundation is covered with expanded polystyrene plates.

Then there are layers of sand and gravel, and a rough screed is poured on them. Spilling with a liquid cement-sand composition in this case is undesirable. A rough screed is needed for reliability. After it dries, a layer of waterproofing should be applied. At high level groundwater it is better to use not polyethylene, but welded waterproofing or polymer membranes. They are more reliable, although they are more expensive.

Underfloor heating construction on the ground

Further, all the layers, as previously recommended: a heat insulator, a metal-coated hydrobarrier, and fasteners with underfloor heating pipes (or heating cables, for example). All this is covered with a metal reinforcing mesh and filled with another layer of mortar. And then - depending on the used finish coat for underfloor heating.

Results

Warm floor in the house on the ground - quite complex structure. In order for it to be reliable, a rough screed is needed. If for some reason it is not possible to make a screed, you can, in extreme cases, get by with tamping the layers.