It is difficult to build a solid foundation on unstable ground. In such cases, a slab base is used. It acts as a foundation of shallow depth, drifting along the site, while moving soil masses. Since the entire structure is moving, no destructive stresses arise.

For the correct operation of this type of foundation, it must be protected from freezing. Insulation of a monolithic foundation slab:

• prevents the destruction of concrete from temperature differences;
• contributes to the warm floor of the first floor;
• makes it possible to save on heating the building;
• reduces heaving of the soil under the building.

The choice of insulation

Not everyone, even the most effective material, is suitable for working in the ground or in its vicinity. When choosing a material, you need to be guided by:

• moisture resistance. Being saturated with water from the ground, the product loses its insulating properties. Expanding when freezing, moisture violates the integrity of the coating, nullifying all work;
• strength. Seasonal movements of soil masses create perceptible pressure on the material. It is especially noticeable in rocky soils. Sharp edges can push through the product, leaving cracks or breaks in it;
• resistance to aggressive environments. Soils are often chemically and biologically active. The groundwater may contain an increased concentration of salts. All these factors lead to the premature destruction of the insulation.

When installing insulation inside the building, the material must be non-combustible. If there is a possibility of fire, no harmful substances should be released that can cause suffocation.

With all this, the service life of the insulation should be no less than the service life of the finishing material. In this case, you do not have to change it before the coating becomes outdated. Otherwise, you will have to dismantle the finishing cloth that still meets the standards.

Extruded polystyrene foam is often used for zero cycle work. Insulation of the basement slab with expanded polystyrene, made in accordance with all the rules, allows you not to worry about the safety of concrete and saving heat.

Characteristics of expanded polystyrene

Expanded polystyrene is used for thermal insulation of the foundation slab:

• outside;
• from the inside;
• in the body of concrete

Outdoor insulation technology

The height of the slab can be from half a meter. Freezing around the perimeter is the most dangerous for the foundation. Therefore, in general, the insulation is attached precisely along the side surfaces.

Before covering the foundation with a layer of insulation, it must be waterproofed. Despite the fact that polystyrene foam is waterproof, the coating is not seamless. Moisture penetrates into the seams between the slabs, which can destroy the slab.

Waterproofing is carried out by applying bitumen mastic or melting paraffin on the surface and edges of the slab. The second method is more economical and reliable. With the help of a gas burner, lumps of paraffin are melted. The material is evenly distributed over the surface, absorbing into it.

Waxing closes the pores of the concrete, creating a moisture barrier. Full adhesion helps to prevent flaking of the insulation. This means that insulation can be easily attached to it.

Expanded polystyrene plates are mounted on glue or on a cement-sand mortar. The first option allows you to carry out insulation at subzero temperatures. The underground part is fixed only by gluing. This is necessary to avoid disturbing the hydro-barrier.

The basement part of the insulation of the slab foundation with expanded polystyrene is additionally fixed with plastic dowels. For this, holes are drilled through the glued plates. They go through all the insulation and part of the foundation.

The adhesive is applied around the perimeter of the board and in several stripes in the center. It is kept for 1 minute and the plate is pressed to the surface for a couple of minutes. After gluing, the bottom plates are sprinkled with a layer of sand. This helps to fix them in the mounting position.

The second row of insulation is mounted with an offset of the seams. It is advisable to make a bandage and horizontal joints. This helps to avoid cold bridges.

If the thickness of the slabs is not enough, the insulation is carried out in two layers. Products with maximum thicknesses are taken to avoid the installation of several layers. The plates of the upper layer should overlap the seams of the lower ones.

Fixation with umbrellas is carried out at five points of the slab. The dowels are mounted after the plates are completely glued, but no later than three days later.

After installation, the joints are sealed with polyurethane foam. Excess foam is trimmed and the surface is plastered over the mesh. The mesh is necessary for better adhesion of polystyrene foam and plaster.

Internal insulation technology

When insulating a monolithic foundation slab from the inside, the material is laid in two ways:

• Over the plate;
• In the body of concrete.

In the first method, the sequence of work is as follows:

• waterproofing is arranged along the foundation slab, with an approach to the wall;
• logs are screwed on top of the waterproofing layer;
• a layer of insulation is arranged between the lag;
• over the insulation, a waterproofing film is attached to the logs;
• a plank base, plywood or OSB boards are mounted on the film;
• over the subfloor, a cork, expanded polyethylene or pine needles backing is laid. A finishing floor is mounted on it.

You can do without lag. In this case, there is a complete insulation of the slab foundation with expanded polystyrene. The material is laid in a continuous layer. Immediately on top of it, the underlay and the final floor covering are laid.

When installing in concrete, the following work is performed:

• the base plate is waterproofed;
• a layer of insulation with a thickness of at least 100 mm is arranged. It is better to use products with a locking system;
• a PVC film with a density of not less than 1.42 g / cm3 is laid on the insulation;
• reinforcing mesh is laid. Its role can be played by a masonry mesh with a cell of 100 * 100 mm;
• the surface is filled with a screed not thinner than 5 cm;
• the topcoat is laid on the screed.

For internal insulation, only self-extinguishing polystyrene foam should be used. For installation under a screed, products of the G4 flammability class can be used.

Insulation of the body of the foundation slab

Warm concrete is used in many areas of construction. It can be purchased in the form of a ready-made mixture or manufactured in a construction site. For preparation, granular polystyrene foam is added to the initial mixture to form the foundation slab.

For the construction of structural elements, polystyrene concrete with a density of D1200 is used. When preparing 1 cube, the composition includes:

• 300 kg of M400 cement;
• 1.1 m3 of expanded polystyrene granules. It is better to use granular rather than crushed material. It has the shape of a ball, which leads to a better enveloping with a cement mixture;
• 800 kg of sand;
• PAD. Often saponified resin is added. Its presence in the composition provides better adhesion and increases heat-shielding properties.

When creating such concrete, you need to remember about shrinkage. It is 1mm per 1m of surface. The plate needs to stand for some time after curing. It is necessary to arrange a leveling screed over the surface.

The flammability class of such a product is G1. The concrete itself does not burn, but the insulation granules are exposed to fire. As a result, pores are created in the body of the foundation slab. They reduce the density of the structure and increase its moisture absorption.

The thermal conductivity of such a plate will be approximately 0.105 W / (m * C). The product requires additional insulation of the slab foundation from below. The thickness of the insulating material will be less than that of plain concrete.

The choice of the type and technology of insulation of the foundation slab depends on the design features of the building and the construction site. It is worth choosing the optimal solution based on the data of the heat engineering calculation and comparison of the estimated cost.

Underfloor heating pipes must be resistant to damage, since they are subjected to mechanical stress during installation. The best option is products made of cross-linked polyethylene PE-Xа. Photo: StoneHut (2)

How to calculate the thickness of the slab and the section of the reinforcement?

In this case, one should be guided by the standards (SP 50.101.2004 and SP 63.13330.2012). An easier way involves the use of ready-made projects that are available from all large construction companies. To check the calculations and compare options, it is worth using special computer programs, for example Foundation, GIPRO or WINBASE.

On the "classic" Swedish slab, you can immediately erect walls by placing two layers of roll waterproofing under the first crown (or a row of masonry). Photo: StoneHut

Is drainage required around and under the foundation slab?

In swampy and flooded areas, it is highly desirable. In this case, the function of the drainage layer is performed by the addition of coarse crushed stone (20–70 mm). The system will be more effective if tubular drains are laid in the thickness of the bedding (their optimal spacing is 1.5–2 m). Drainage is also required around the perimeter of the slab or blind area. Water should be discharged into a drainage well or to a descending relief; if the groundwater level is less than 1 m from the surface, it is advisable to use an automatic system. The presence of drainage will reduce the risk of freezing of the soil under the house, extend the life of the foundation and reduce the risk of cracking of the blind area.

The slab is poured under the entire house, including the porch and terrace (veranda). If you attach these elements later, there is a high probability of distortions and cracks at the junction of the walls.

How to build communications?

Water supply and sewer pipes, as well as an electric cable (if its underground input is provided), are laid when installing a pillow. They are protected from possible damage with an EPSP layer or wrapped in several layers of waterproofing material. In principle, it is possible to connect to communications even after the end of construction - through a wall-mounted insulated box.

But sometimes they first build a monolithic or masonry base. Photo: "Foundation 47"

Is it possible to build a slab foundation during the cold season?

This is possible, but it comes with increased costs and the risk of reduced structural reliability.

Concrete with winter modifying additives is 25–40% more expensive than usual, and the construction of a heated dome, which is indispensable in severe frost, will cost 30–100 thousand rubles. In winter, earthworks are very difficult, and all other tasks are complicated by the cold and lack of daylight.

The blind area is poured over a drainage pad and reinforced with a road mesh. Photo: IZBA De Luxe

Is it possible to build a slab foundation from homemade concrete?

Only for a small household building. If we are talking about a house, then this method is excluded, because when pouring concrete in small portions, numerous "cold" joints cannot be avoided, which will dramatically reduce the stiffness of the slab and its resistance to cracking. When delivering ready-mixed concrete, the break between the arrivals of the auto mixers should be 3-4 hours.

It is advisable to make an uninsulated blind area in fragments 1–1.5 m long in order to avoid the appearance of cracks. Photo: IZBA De Luxe

Can the flooring be laid directly on the surface of the Swedish board?

Yes, as a rule, you can do without. In extreme cases, add a thin layer of self-leveling mixture. Note that it is advisable to lay coatings on the Swedish slab that conduct heat well, for example, porcelain stoneware or stone tiles, a special laminate.

On open terraces, a weather-resistant coating with an anti-slip surface is laid on top of the slab, for example, porcelain stoneware or clinker tiles, larch or composite decking. Photo: ShutterStock / Fotodom.ru

3 myths about reinforcement

1. The reinforcement should be knitted, not welded, as welding negatively affects the strength of the metal. In reality, this only applies to alloyed fittings, which are practically not used in individual construction. It is easier and cheaper to knit fittings, which explains the popularity of this installation method.
2. You can knit reinforcement with anything and not necessarily tightly, since connections are only needed for mounting positioning of the frame elements. Meanwhile, according to building codes, when knitting overlapping and cruciform connections, the rods must be pulled together without a gap. Overlaps (their length is equal to 40 diameters of reinforcement) should be tied with steel wire in several places.
3. The diameter of the reinforcement is not important if the required reinforcement ratio (the ratio of the cross-sectional area of ​​the reinforcement to the cross-sectional area of ​​the concrete structure) is met. In fact, the use of thin reinforcement (8 mm) increases the labor intensity of installation and complicates the quality control of the work performed.

In private construction, it is advisable to increase the reinforcement ratio by at least 20%, compared with the recommended standards, and use high-quality concrete.

A variant of the construction of the insulated slab foundation

1 - sand gravel pillow; 2 - insulation (EPS boards); 3 - drainage pipe; 4 - reinforcing cage; 5 - pipes of the underfloor heating system; 6 - flooring (tiles); 7 - drainage membrane; eight - ; 9 - gravel backfill; 10 - moisture resistant finish. Photo: TechnoNICOL

The underfloor heating system is tested in two stages. After installing the pipeline and before pouring the concrete slab, the integrity of the pipes is checked with a fluid pressure that exceeds the working pressure by 1.5 times. The test duration is 3 hours. As an exception, if a hydraulic test is impossible (for example, due to frost), a compressed air test is allowed. When pouring concrete, the pipes must be filled with cold heat carrier and under pressure (working or test). After the concrete has set the required strength, a thermal test is carried out, which lasts seven days. First, for three days, a heat carrier heated to 20–25 ° C should circulate in the system. Then the maximum operating temperature is set, which is maintained for four days. During this period, the uniformity of heating of all circuits is checked using a contact thermometer.

Sergey Bulkin

Expert of the REHAU company

Aggregated calculation of the cost of construction of an insulated slab foundation with an area of ​​80 m2

When choosing a foundation, they are guided, firstly, by reliability, and secondly by cost. It would be nice if both qualities were combined, but this is not always possible. One of the most reliable bases for building a house is a monolithic slab foundation. In some cases - on normal soils for light houses, it is relatively inexpensive, in difficult cases it can be expensive.

Scope and types

A monolithic slab for a house belongs to floating unburied foundations, there are also shallow foundations. It got its name due to the fact that the reinforced concrete base is poured under the entire area of ​​the house, forming a large slab.

A prerequisite is the presence of a sand and gravel cushion, which redistributes the load from the house to the ground, and serves as a damper in case of frost heaving. Often, such a foundation is the only possible solution. For example, on unstable, loose soils or on clays with a large freezing depth.

The construction of the monolithic slab foundation is simple and reliable, but its production requires a large amount of reinforcement and large volumes of high grade concrete (not lower than B30), because the entire area occupied by the building is reinforced and concreted, and even with a margin - for greater stability. Therefore, such a foundation is considered expensive. In principle, this is so, but it must be considered. In some cases, its cost is lower than that of a deep belt - due to less land work and less concrete.

The depth of the monolithic slab is determined depending on the mass of the house and the type of soil. At shallow depth on heaving soils in winter, the house, together with the base, can rise and fall. With the correct calculation of the reinforcement and the thickness of the slab, this does not affect the integrity of the building. The slab compensates for all changes due to the elastic force. In the spring, after the soil has melted, the house "sits down" in place.

There are four types of slab foundations:

• Classical. A reinforced concrete slab is placed on a sand and gravel cushion with or without insulation. The thickness of the concrete layer is 20-50 cm, depending on the soil and the mass of the building. The thickness of the pillow layers depends on the depth of the fertile layer - it must be completely removed. The resulting excavation can be filled with sand and gravel by 2/3.

  

• Insulated Swedish plate (USHP) with built-in underfloor heating. Firstly, it differs in that the slab formwork is non-removable - made of L-shaped polystyrene foam blocks. This significantly reduces heating costs - heat loss is minimal. Also, underfloor heating pipes are laid on top of the insulation, reinforcement is laid on them (sometimes under them) and everything is poured with concrete, the thickness of the concrete layer is 10 cm. All communications, including water supply and sewerage, are laid even at the stage of base preparation - in a sand cushion. That is, after the foundation is made, the heating system is ready and the engineering systems are installed. This approach allows you to speed up construction, but the foundation itself is expensive. This type of foundation requires a competent engineering calculation and the same execution: when calculating and laying communications, one cannot make mistakes, since alterations are impossible. Also, there are questions about the repair of systems embedded in the foundation. It is impossible, therefore expensive materials are laid with a long warranty.

  

  USHP - insulated Swedish plate with built-in underfloor heating

• Russian - plate with stiffeners. To strengthen the structure for heavy houses and in difficult operating conditions (strong frost heaving), Russian scientists came up with the idea of ​​making more massive stiffeners. They are usually arranged under load-bearing walls. At the same time, the complexity of the work increases - stiffening ribs are separately arranged, separately - a slab. But the bearing capacity of such a foundation is much higher, which makes it possible to reduce the thickness of the slab - up to 10-15 cm.

  

  

  Insulated slab construction technology

  Saving energy is becoming a really relevant topic, so few people build a foundation without insulation. Any slab foundation is a multi-layer structure, and in the case of insulation of layers, even more. To achieve the desired quality level, each level must be met carefully. Let's dwell on each in more detail.

  

  Preparation of the base

  The dimensions of the pit for a monolithic slab should be at least 1 meter larger than the building itself. In this area, fertile soil is completely removed. Its thickness is different in different regions - from 20-30 cm to 50 cm and more. In any case, they remove everything.

  

  Drainage pipes are laid along the edge of the pit, just below the general level of the bottom, to drain surface water into drainage wells. This measure is necessary so that the walls and the foundation itself do not get wet.

  

  The bottom is leveled, the pits are filled up, the humps are removed, everything is carefully leveled to the level of the horizon and compacted. Rolls out onto the leveled bottom. It should cover not only the bottom, but also the walls. The canvases are spread with an overlap, the edges are glued together with reinforced tape. Geotextile prevents plant roots from germinating, and also prevents sand washing out, which serves as a damper cushion.

  

  Clean sand of medium grain size is poured onto the laid geotextile. Sand layer - 20-30 cm. It is poured in thin layers, evenly distributed and tamped in layers. A layer of sand that can be tamped with a manual vibrating plate is 8-10 cm. These are the layers that sand is laid. It should also be laid in a level, in the same layer throughout the excavation.

  

  The thickness of the layer can be controlled with the stretched cords. They are tied to hammered stakes, specially made supports - benches, to the formwork installed in the level (see the photo below). All cords must be in a horizontal plane. Knowing the initial distance from the bottom of the pit to the stretched threads, you can determine the height of the poured layer.

  Crushed stone is poured onto the compacted sand. The entire volume is poured at once, evenly distributing it over the site. The leveled crushed stone is rammed to a high density.

  

  At this stage, sewer and water pipes are laid. Ditches of the required depth are dug in the already rammed rubble. They should be such that there is some space around the embedded elements. Pipes are laid in the ditches, covered with sand, leveled, sand is compacted with a shovel or board. A more severe compaction can lead to cracks. Therefore, pipes are laid after ramming.

  Concrete preparation

  Formwork is placed around the perimeter of the pit. It is usually assembled from a 40 mm thick board or 18-21 mm plywood. The height of the formwork for a monolithic slab is the total thickness of the remaining layers. Along its edge it is convenient to control the level of concrete when pouring, therefore the board must be edged. To save material, you can set the formwork only for preparation. After the concrete has set, it is dismantled and placed higher, using it again to pour the main slab. But the loss of time with this approach is significant, so this is not always done.

  In any case, the formwork is supported from the outside with stops and jibs. The structure must be rigid to support the weight of the concrete.

  A layer of concrete of 100 mm is poured onto the compacted gravel. It can be concrete of low grades - B7.5 - B10. Concrete preparation will be a reliable basis for laying waterproofing and insulation, and also serves to distribute the load from the house more evenly.

  

  Waterproofing

  Since the monolithic foundation slab is completely buried in the ground, it needs careful waterproofing. Therefore, two types of materials are usually used: coating and roll. The base is first thoroughly dedusted, then impregnated with a diluted kerosene or solvent primer (and the sides of the concrete preparation are also coated). It is sold very thick and does not adhere well to concrete. As a result, rolled waterproofing does not adhere well and the foundation will get wet. When diluted, it becomes more fluid and penetrates deeper into the concrete. At the same time, it almost does not lose its properties.

  When laying roll waterproofing, it is released outside the foundation by 10-15 cm. The sheets are rolled out with an overlap, the connecting edges must be coated with bituminous mastic and pressed well. When laying out, care must be taken that there are no creases and waves.

  If the water table is high, you may need two layers of roll-up waterproofing. It is then rolled across, and glued to a primer (bituminous waterproofing), but you can no longer dilute it.

  

  Waterproofing of a monolithic foundation slab is double - coating and roll

  Of rolled waterproofing materials, Gidroizol, TechnoNIKOL Technoelast EPP-4 on high density polystyrene proved to be the best. Technolynicol of this brand has a high tensile strength of about 60 kg, which increases the chances that it will not be damaged during further work. You should not use roofing material, no matter how much you want to save money. In modern design, it is too thin and brittle, and quickly loses its properties. You cannot replace the waterproofing in the slab, therefore, lay the best material.

  It is also possible to reduce the capillary suction of moisture through the slab with the help of liquid impregnations such as Betonit. It significantly reduces moisture absorption. It penetrates to a depth of 50-60 cm, so that it will saturate the concrete preparation through and through. The disadvantage of this material is its high price, but the material has excellent properties.

  Warming

  For insulation of the slab foundation, extruded high-density polystyrene foam is used. The thickness of the insulation layer is 10-15 cm, depending on the region (10 cm is enough for the Middle Strip). Laying is carried out in at least two layers, overlapping the seams, which form cold bridges. It takes more time, but heating costs will be lower. If the slabs have an L-shaped lock, they can be laid in one layer.

  

  Since expanded polystyrene is "not on friendly terms" with oil products, a dense polyethylene film is spread on it, and then a heat-insulating material is laid.

  Reinforcement

  For the reinforcing frame, ribbed reinforcement of class AIII with a diameter of 12-14 mm is used. It is laid up and down, with a step of 15-30 cm, it can have one or two layers. It all depends on the type of soil and the mass of the building. All reinforcement parameters are counted separately.

  The reinforcement should be at least 5 cm away from the edge of the slab. Therefore, it is placed on special supports that provide the required gap.

  

  When reinforcing, a cage is obtained; at each intersection, the rods are tied together with a special soft steel wire. There are also connection techniques - using plastic clamps or welding. It is quick to tie with plastic clamps, but not everyone trusts them. Welding is not recommended, because the weld is the most vulnerable place for rust, and the connection is too rigid. When using wire and clamps, the whole structure can play a little without breaking the bond, and when welding, such movements lead to the fact that the seam bursts. As a result, the reliability of such reinforcement is low.

  Pouring the foundation slab with concrete

  The thickness of the slab is calculated for each specific case and can be from 20 cm to 50 cm. When pouring, concrete is used not lower than the B30 grade. The entire perimeter must be filled in one day, avoiding the appearance of vertical seams. Therefore, for concreting a slab foundation, concrete is most often brought ready-made: large volumes are required at a certain time.

  

  The timetable for the arrival of the machines should be calculated so that you have time to distribute the first portion and compact it. Construction vibrators are used for compaction, which create high-frequency vibrations. As a result, all the air is removed, the concrete mixes better, becomes more fluid and plastic. The result of this treatment is not only a flat concrete surface, but also a higher hygroscopicity class.

  As a last resort, you can fill the slab with horizontal layers. Vertical division in this case is unacceptable, since cracks are likely to go at the joints.

  Curing

  For the normal process of concrete hardening, a sufficient humidity level of 90-100% and temperatures above + 5 ° C are required. It is advisable to pour the stove in warm weather with a temperature of about + 20 ° C. This temperature regime is optimal for the hardening process. Caring for the concrete of a monolithic slab consists in preventing mechanical damage and maintaining moisture.

  Immediately after laying, the concrete is covered with a diaper or tarp. This prevents it from heating up from the sun, it is not affected by the wind. The film is glued into large panels. The strips are laid with an approach of 10-15 cm, glued with tape. It is advisable that there are as few unscrewed joints as possible, that is, the shelter should consist of one or two pieces, if one is too inconvenient. In this case, individual pieces of film overlap one another for at least half a meter.

  

  The dimensions of the film are such that the side surface of the formwork is also closed, and a load could be laid on the edges of the film, which will not allow the wind to lift it. Also, with a load - boards - they press the place of the overlap of two panels in order to reduce the windage, they can be laid out on the surface.

  If the air temperature is above + 5 ° C, approximately 8 hours after pouring, the concrete is poured with water for the first time. Irrigation should be drip, not jet. In order not to damage the surface with drops, you can lay burlap on it or sprinkle a layer of sawdust on it, and cover it with a film on top. Covering material is watered, and it maintains the moisture content of the concrete. In any case, watering is carried out only at temperatures above + 5 ° C.

  

  If there is a threat of freezing, the slab and formwork are additionally insulated. You can use any heat-insulating materials, both prepared for building a house, as well as sawdust, straw and other improvised means.

  When to remove the formwork

  

  Differences between insulated monolithic Swedish slab and video about its construction

  As mentioned earlier, the insulated slab for the house developed by Swedish builders is energy-saving. During its construction, a permanent formwork made of extruded polystyrene foam is used. As a result, heat leakage into the ground is minimal. The second fundamental difference is the water underfloor heating system built into the slab.

  Since engineering systems are poured into the thickness of concrete, it requires an accurate and competent calculation. High demands are placed on the execution as well. Even small mistakes are critical. You can do UWB yourself, but it is better to order the project. See the following photo for an approximate cost breakdown. The amounts are no longer relevant, but the percentages are fair. The cost of the foundation project is about 1%.

  

  In the following videos, you will see the stages of making a Swedish slab for a specific house. Many useful devices are described that will facilitate the work, explanations are given on some of the features.

  And also look at how the Germans are pouring such a plate. There are also many useful nuances.
  

The Swedish slab is a low-depth insulated monolithic slab foundation. The main feature of this technology is that the entire base of the house is based on a layer of insulation (under the stove). Under a warm house, the soil does not freeze or heave. Such a foundation is suitable for any soil, at any depth of groundwater.

This technology is based on the basic principles of design and construction. shallow foundations on heaving soils described in Organization standard (STO 36554501-012-2008), developed by the research, design and survey and design and technological institute of foundations and underground structures (NIIOSP) named after. N.M. Gersevanov (Federal State Unitary Enterprise Research Center "Construction"), Federal State Unitary Enterprise "Fundamentproekt", Moscow State University. M.V. Lomonosov (Geological Faculty, Doctor of Technical Sciences LN Khrustalev) and the technical department of PENOPLEKS SPb LLC.

The Swedish slab technology combines the construction of an insulated monolithic foundation slab and the possibility of laying communications, including a water floor heating system. An integrated approach allows you to obtain in a short time an insulated base with built-in engineering systems and a flat floor, ready for laying tiles, laminate or other coverings.

The main advantages of the insulated Swedish plate:

• The foundation and the laying of communications are carried out in the course of one technological operation, which reduces the construction time.
• The ground slab surface is ready for flooring;
• The PENOPLEX FUNDAMENT® thermal insulation layer, about 20 cm thick, reliably protects against heat loss, which means a significant reduction in the cost of heating the house and an increase in the efficiency of the "warm floor" system;
• The soil under the insulated slab does not freeze, which minimizes the risks of frost heaving problems in the base soils;
• Laying the foundation does not require heavy equipment or special engineering skills.

Installation features

To ensure the normal operation of the insulated Swedish plate (USHP) and prevent frost heaving, it is necessary to provide for a groundwater drainage system (drainage system around the perimeter of the structure). An important role is also played by a non-porous preparation device (a pillow of coarse sand, crushed stone). In the event that a combination of layers of crushed stone and sand is used, it is necessary to provide for the separation of these layers by geotextiles (when the soil of the fine fraction is located above the larger one). All the necessary communications (water supply, electricity, sewerage, etc.) and inputs must be laid under the stove in advance.

The design of the Swedish slab assumes the transfer of all loads from the structure (own weight, operational loads, snow, etc.) to the insulation layer, which is why high strength requirements are imposed on the thermal insulation material used. The most rational option for this design is PENOPLEX FUNDAMENT® heat-insulating plates, which have practically zero water absorption and high compressive strength.

Instructions for use:

• Step 1. Removing the top layer of soil (usually about 30-40 cm);
• Step 2. Compaction of sand and gravel preparation (coarse sand, crushed stone);
• Step 3. Installation of drainage along the perimeter of the structure and pipes of utilities;
• Step 4. Laying the PENOPLEX FOUNDATION® board elements and slabs in the base;
• Step 5. Mounting the reinforcement cage on supports;
• Step 6. Laying pipes for the floor heating system, connecting them to the manifold and pumping air into them;
• Step 7. Pouring a monolithic slab with a concrete mixture.

The heating system integrated into the foundation structure ensures a comfortable indoor environment. And the use of durable and absolutely moisture-resistant PENOPLEX FUNDAMENT® boards as a base preparation will significantly increase the thermotechnical reliability and efficiency of the underfloor heating system. Ordinary water or antifreeze can be used as a coolant in the system (if it is not possible to always maintain a positive temperature in the room during the winter period). Almost all types of pipes can be used as heating pipelines in water underfloor heating systems: metal-plastic, copper, stainless steel, polybutane, polyethylene, etc.

When laying heating pipes, the following rules are followed:

• The higher heat output of underfloor heating is achieved by tighter pipe laying. Conversely, that is, the heating pipes must be laid more tightly along the outer walls than in the middle of the room.
• It makes no sense to lay pipes denser than after 10 cm. Denser laying leads to a significant waste of pipes, while the heat flux remains practically unchanged. In addition, a thermal bridging effect may occur when the supply temperature of the heating medium equals the processing temperature.
• The distance between the heating pipes should not be more than 25 cm to ensure an even temperature distribution over the floor surface. To prevent the "temperature zebra" from being perceived by a person's foot, the maximum temperature difference along the length of the foot should not exceed 4 ° C.
• The distance of the heating pipes from the outer walls must be at least 15 cm.
• It is not recommended to install heating circuits (loops) longer than 100 m. This leads to high hydraulic losses.
• Pipes must not be laid at the junction of monolithic slabs. In such cases, two separate contours must be placed on opposite sides of the joint. And the pipes crossing the joint must be laid in metal sleeves, 30 cm long.

Insulation of a monolithic foundation slab is necessary in areas with cold climates. Such measures are required in order to protect the base from the harmful effects of the environment, preserve warmth, coziness and comfortable living conditions in the house. One of the most common materials for insulation are polystyrene foam and polyurethane foam.

Insulation of the foundation of a monolithic type with expanded polystyrene

Thermal insulation of base plates in this way is a relatively young form of modification of private houses. It began to be used in the 50s - 60s of the XX century. This type of plate insulation is durable and has a long service life. According to statistics, the popularity of expanded polystyrene is growing steadily every day.

Strengthening monolithic slabs with expanded polystyrene proved to be a very successful solution in the construction of houses, because their service life is more than 50 years. After carrying out various tests and checks, it became clear that the material did not change during the entire period of operation.

It follows from this that the growing popularity and steady increase in the consumption of expanded polystyrene is a regularity. Over the past 20 years, its use has increased tenfold. The main consumers of this material are Europe and North America.

Extruded polystyrene foam for insulating a monolithic base plate is a material with a uniform structure, consisting of closed cells. Due to the low density of the material, its thermal insulation properties increase. You should also know that expanded polystyrene has increased strength characteristics and is able to withstand rather heavy loads.

Expanded polystyrene practically does not allow water to pass through and is not afraid of the effects of chemically aggressive environments. Thermal insulation with this material is done in regions with harsh winters and very cold weather. Expanded polystyrene copes well with repeated cycles of frosting and defrosting, while its operational characteristics do not change at all. Expanded polystyrene is usually sold in the form of slabs.

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Why polystyrene and not another material?

1. A site for the foundation is marked.
2. A layer of soil is removed from above. The depth depends on the construction project. When removing the soil, you must try to make the bottom as even as possible. For this, the last 0.2 - 0.3 m is removed by hand. A layer of sand is poured onto the prepared site and then rammed.
3. Temporary formwork is being installed, and a concrete base is being prepared. The formwork is poured with a small layer of concrete. Base reinforcement is not required.
4. After the concrete has frozen, they begin to lay the polystyrene foam plates, while it is necessary to combine the mounting grooves and try not to leave large gaps.
5. A polyethylene film is placed on the laid layer of insulation. The joints are glued with tape. Polyethylene creates a waterproofing layer. In addition, the film prevents concrete leaks between the joints of the insulation slabs.
6. Formwork and reinforcement cage construction is in progress. Concrete is being poured.
7. After complete drying, the formwork is surveyed.
8. The side walls are additionally insulated with expanded polystyrene.

A few tips:

• work starts from any corner of the foundation;
• the slabs must be laid from bottom to top with an offset of the rows, that is, something should look like brickwork;
• at a height approximately equal to the width of the slab, pull the rope. The horizontal tension is checked using a building level;
• the first row of the thermal insulation layer is laid. This is done so that the subsequent rows of plates do not diverge, otherwise all the insulation will become simply useless.

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How to properly mount polystyrene foam plates on walls?

The foundation wall is covered with spread mastic. Then expanded polystyrene is attached to it and tightly pressed. All plates of the row are mounted in the same way.

When carrying out work, it is necessary to carefully monitor the connection of adjacent slabs. It should be clear, without gaps and be in the lock.

The joints on the ridges of the locks are cut off at the corners. If necessary, the joints are additionally filled with polyurethane foam.

As the high rows are laid, the lower ones are covered with soil. Such actions facilitate the work and help to press the material.

Plates located below ground level are glued only to the mastic.

This is to prevent damage to the waterproofing.

Insulation located above the ground can be additionally strengthened with dowel nails (umbrellas). All this can be easily done with your own hands, you just need to be very careful. To fix the base on the walls, holes are drilled using a punch. Umbrellas are fixed in the center and at the junctions of adjacent slabs.

The foundation insulated with expanded polystyrene is so popular for the following reasons:

• when using this technology, you can save up to 40% of money;
• reduction of heat loss reaches 20%;
• the waterproofing layer of the foundation will last 2 times longer;
• expanded polystyrene guarantees quality and long service life;
• slabs reliably protect the waterproofing layer, ensuring the drainage of accumulated groundwater.

From the above, it becomes clear that, insulated with expanded polystyrene, it will serve for a long time, and the house will be cozy, comfortable and warm. In addition, the material is absolutely safe from an environmental point of view and has a low cost, which clearly tilts the choice in its direction when a long construction is ahead.