USHP foundation: technology for manufacturing the structure

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The construction industry does not stand still. Manufacturers strive to produce improved materials and offer new technologies, thanks to which they can not only reduce the cost of construction, but also improve the technical performance of the final product. One of the latest developments, which originated in Sweden, is the USP foundation - a technology for economical and quick construction of the foundation for a private house or two-story cottage.

A monolithic foundation made from an insulated Swedish slab is an excellent alternative to a traditional tile foundation

Types of slab foundations, their characteristics

Currently, there are three types of slab foundations, each of which has its own distinctive features. The Russian version, which was designed by domestic designers, is considered traditional. The product is a thick monolithic reinforced concrete slab with massive ribs. The foundation is characterized by a large strength reserve and lack of deformation, due to which it can be used under extreme operating conditions.

Finnish slab manufacturing technology step by step

The disadvantages of the design include insufficient insulation and the need to pour concrete twice: the first - to create stiffeners, the second - to form the slab itself. However, this increases the service life.

The foundation is in the form of an insulated Finnish slab, originally from Finland. The design has a smaller thickness, but is characterized by sufficient strength. It is well insulated and adapted to a heated floor system. Such a foundation is a cold circuit. Thermal insulation with a thickness of at least 150 mm is mounted on the slab, cutting off the cold contour of the foundation from the warm floor of the first floor of the building, which is installed in an additional reinforced screed.

Less energy-saving, but more economical compared to the Finnish version, is the insulated Swedish stove. USHP does not require additional screed, since the heated floor system is mounted directly into the slab, the thickness of which reaches a minimum size.

What is USP: areas of use

The insulated Swedish foundation slab is represented by a shallow monolithic slab foundation. It has insulation along the entire perimeter and sole area. This is a finished rough floor surface of the first floor with built-in heated floor and utilities.

The high strength and heat resistance of the USHP foundation allows it to be used in difficult climatic conditions for buildings made of any material

This type of foundation is used in building projects without a basement or basement. It is advisable to use USHP technology for structures with a side size of 15 m in the following cases:

for cold regions where, thanks to such a foundation, heat loss from the house is reduced;
in areas with high groundwater levels;
in projects of private houses where heated floors are used;
in the case of using half-timbered technology, as well as in the process of creating a panel, panel or frame house;
when choosing block or brick masonry;
on heaving and weak soils that are not characterized by good bearing capacity, which requires the construction of bored or screw foundations.

Leveling the sand base

At the very first stage of constructing the foundation of the USP (insulated Swedish plate), according to the technology, we must level the resulting foundation; for this we can use a laser level or level. We have to make the sand and gravel cushion as smooth as possible. To begin work, we select several points of our foundation and measure the heights, record the resulting figures on paper and draw conclusions about at what point we will need to add or remove a layer of sand:

After all the points we have chosen as starting points for leveling the base of the monolithic foundation have acquired the same height, we can lay beacons on the sand cushion. In our case, we used long reinforcement bars:

We level the sandy base using a long straight board or a long building level, which must be evenly moved along the laid reinforcement bars:

USHP foundation design: cross-sectional photo of the product

The structure consists of the following layers, which are clearly shown in the cross-sectional drawing of a Swedish foundation slab:

concrete pouring;

Swedish slab foundation in section

reinforced layer;
depreciation layer;
insulating layers.

A concrete pour, or monolith, is represented by a conventional foundation with a thickness of only 10 cm, thanks to which the structure is created in one day. This has a positive effect on the quality of the slab, namely: layering is eliminated and the cost of work is reduced. A heated floor system is laid in this layer. The base is insulated from the ground with insulation, which is represented by extruded slab polystyrene foam.

Reinforcement is also carried out in a short time due to the use of a small number of metal rods. A tightly knit reinforced mesh prevents cracking of concrete and prevents damage to the foundation due to natural soil movement.

The traditional depreciation layer, consisting of sand and crushed stone, which is used in a conventional foundation, is supplemented using this USP technology with a layer of clay. Thanks to this, geotextiles laid between mineral layers are not exposed to moisture. An additional waterproofing layer in the foundation is necessary in order to protect the structure from the influence of groundwater, which can erode the layers. In the thickness of the sand under a layer of insulation, sewerage and a water supply system are installed, the nature of which affects the price of the USP.

Reinforced mesh prevents cracking of concrete and prevents damage to the foundation

To create a durable and strong structure, it should be insulated, so that the foundation will not crack and heave during temperature fluctuations. The process is carried out using styrene derivatives, as a result of which the service life increases several times. The insulation is laid not only from below, but also vertically along the perimeter of the slab, duplicating the base formwork. Also, the layer is located under the blind area of the building horizontally at the depth of the base of the reinforced concrete structure. This technology increases the cost of USHP, but reduces further costs for heating the room.

Drainage communications are necessary to create a system for removing moisture from the foundation, which prevents it from damage. A waterproofing layer with vapor barrier properties protects concrete from moisture.

Advantages and disadvantages of USP foundation

The USHP foundation, which can be ordered from any large construction company, is characterized by a number of distinctive advantages:

low cost of work, which is associated with a small amount of building materials and the involvement of a small number of workers;

Heating (warm water floor system) and other utilities are built into the Swedish stove

high speed performance;
thanks to the additional layer of insulation, the possibility of freezing of the soil under the base of the foundation is eliminated, which will save the slab from heaving and shrinkage of the base;
the foundation slab is a full-fledged subfloor on which tiles can be laid without first leveling the surface;
installing a heated floor in the foundation will reduce heating costs in the future due to lower thermal energy consumption;
the insulation is characterized by high compressive strength and shrinks the building by 2%;
the thermal insulation layer is not affected by moisture, which increases its service life;
due to the fact that the foundation is insulated, dampness and mold will not form in the house;
the appearance of insects and rodents is excluded in the insulating layer;
the small thickness of the thermal insulation layer provides the required thermal conductivity coefficient;
the presence of edges on the thermal insulation slabs eliminates the creation of cold bridges;
the plate simultaneously performs heating, thermal insulation and load-bearing functions;

The base of the USHP foundation is already a subfloor, ready for any floor covering

has a durable design while maintaining all technical and economic characteristics;
due to its high heat capacity, it can be used in regions with cold climates.

Disadvantages of USP:

the foundation slab is created exclusively on a reliable foundation, which excludes its installation on muddy, peaty or vegetative soils;
a significant part of the engineering communications is located in the thickness of the slab, as a result of which access to them is limited;
USHP cannot be used in the construction of heavy multi-story buildings;
the foundation excludes the creation of a basement in the house.

Useful tips when installing a foundation

The Swedish foundation consists of several layers, each of which has an important functional purpose. It is very important to properly organize each layer in order to obtain a reliable, strong and durable structure. There are important points to consider here. The thickness of the sand or gravel substrate is determined based on the type of soil, that is, it depends on its bearing capacity. This value is in the range of 300-600 mm, which affects the price of the USP foundation. For the hardest, densest soils, the minimum value is used, and for heaving soils, the maximum value is used.

USP is a combination of a strip base and a concrete floor, which is why this type of base requires precision calculations and adherence to clear technology during construction

Before building a slab foundation, the top layer of soil should be removed. Using a level and a building level, the verticality and horizontality of the surface is checked. The pit must have larger dimensions than the perimeter of the slab. For this purpose, it is necessary to retreat 50-70 cm from the edges of the base markings on each side.

Plates of insulating material should be laid over the entire surface of the foundation. It is not recommended to fasten them with additional adhesive. To create a uniform, dense layer, concrete pouring must be done in one go. Therefore, it is important to correctly calculate the amount of material required to fill the formwork.

Helpful advice! The best option for installing USHP is considered to be concrete of class B20-B25.

Before starting construction, pipes for all communications should be prepared and a diagram of their location should be developed. It is necessary to provide a drainage system along the perimeter of the foundation, which ensures the removal of moisture from the base of the building.

It is important that communications are buried below the soil freezing mark in winter

Survey work, USP calculation and terrain tracing

Survey activities precede the start of construction. They are carried out to determine the nature of the soil and its bearing capacity. The level of groundwater in the area, the composition of the soil and possible fluctuations in the lower layers of the soil are clarified. These indicators must be as correct and accurate as possible in order to subsequently provide a solid foundation. Therefore, here you should use the services of specialists.

The main difference between the calculation of an insulated foundation slab is the sequential determination of the parameters of each layer during construction, taking into account actual loads and impacts. For this purpose, special computer programs are used that determine the individual characteristics of the foundation.

Helpful advice! It is better to design a Swedish foundation with the involvement of professionals, which will avoid many errors in the calculations.

After all the preparatory measures have been completed, they begin directly to build the foundation. To do this, you should mark the territory, which is the drawing of full-scale axes. The contours of the pit are outlined along the ground, cast-offs are installed along which the cords necessary for installing the formwork are pulled. The main advantage of cast-offs (compared to conventional pegs) is the convenient U-shaped design, the position of which is leveled once in the horizontal plane. If the cord is temporarily removed when necessary, no adjustments are required once it is in place.

Before laying the foundation, survey work is carried out, which is aimed at determining the type of soil and its bearing capacity

The pit should be planned larger than the foundation slab. An allowance of about 1 m should be left on each side. Such indents will be used for installing drainage. This can be a ring drainage to lower the groundwater level or a wall drainage used to drain high water, which is formed with the constant accumulation of rain and flood waters of the underlying layer in technogenic zones.

Related article:

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Advantages of an insulated Swedish stove

The main advantages of this type of foundation include:

low labor intensity of construction;
reduced construction cost compared to traditional types of foundation;
the opportunity to immediately get a subfloor, on which all that remains is to do the finishing;
high energy efficiency, allowing you to save on heating;
Possibility of construction on any type of soil.

The advantages are quite noticeable. But this technology also has its disadvantages.

List of required materials and tools

Doing USP with your own hands is not as difficult as it seems at first glance. Before starting work, it is necessary to have a design for a new building and determine the location for construction. You can, of course, use the services of specialists and order a turnkey USHP foundation. However, strict adherence to technology and the use of high-quality materials will allow you to independently create a solid and reliable foundation for subsequent construction.

Before pouring concrete, it is necessary to prepare a flat area and compact it properly with a special machine.

List of materials required for the construction of the USHP foundation:

medium sand;
medium-sized crushed stone;
geotextiles;
extruded polystyrene foam 100 mm thick;
drainage pipes;
wooden boards;
reinforcement bars;
knitting wire;
pipes of different diameters for utilities and water heated floors;
nylon clamps;

To work you will need the following tools:

scoop and bayonet blades;
wheelbarrow;
level;

L-blocks are lined with flat slate for laying the foundation

building level;
screwdriver;
knife;
Bulgarian;
vibrating plate;
deep vibrator;
hacksaw;
concrete mixer;
trowel;
protective clothing.

Excavation work and creation of a drainage system

A warm foundation cannot be laid on a plant layer whose thickness does not exceed 0.3-0.5 m, so it should be removed completely. To do this, you can use bayonet shovels. If the foundation is laid on a fertile layer, it will inevitably shrink, which will be a consequence of rotting organic matter.

Before pouring the USHP foundation, you need to remove the fertile layer, fill it with sand and compact it

Helpful advice! To be safe, it is recommended to treat the area cleared of vegetation with chemicals that stop further plant growth.

After removing the soil, the surface must be compacted using clay, which, in dry crushed form, is poured into the pit, moistened and compacted. Next, geotextiles are laid. The ends of the woven fabric should protrude beyond the future foundation by at least 30 cm.

In order for the slab to always remain dry, it is important to properly organize the drainage system, thanks to which groundwater, storm water and melt water will be drained from the base of the foundation. For this purpose, it is necessary to make a trench along the entire perimeter of the pit with a depth equal to the diameter of the perforated pipes that will be used for drainage. Here you should slope away from the building by 3-4 degrees, which will ensure gravity flow. It is necessary to install vertical wells in the corners of the building, which will provide access to the drainage system for periodic cleaning.

In order for the slab to always remain dry, it is important to properly organize the foundation drainage system

The sequence of actions is as follows:

a layer of crushed stone is laid on the geotextile;
in the corners of the structure, wells are installed, which are created from solid smooth or corrugated pipes with a diameter of 20-30 cm, installed vertically;
installation of corrugated pipes along the perimeter of the building with the ends entering adjacent wells, where the corresponding holes are made;
filling the trench with crushed stone, which is covered with geotextile on top.

Necessary work for organizing the foundation is a Swedish slab.

Before you start making this base, you need to carefully think through everything and prepare everything.

All work is carried out comprehensively, there should be no mistakes.

If the planned building is small in size, then everything can be calculated independently and done with your own hands. The main thing is to take into account that all communications correspond to the project.

Basic parameters of the Swedish slab foundation:

Scheme of pouring the foundation slab.

the thickness of the overall slab is made by casting reinforced concrete and should be from 120 to 180 mm;
along the entire perimeter it is necessary to make stiffening ribs of at least 300×300 mm, they will be the foundation for the load-bearing walls;
Under all future walls, internal stiffeners are made at intervals of 1.5 to 4 mm. Reinforcing strips must be at least 200×200 mm in size;
The depth of the foundation can be any, it all depends on the wishes of the owner, so you need to think about the base in advance. To do this, it is necessary to make the foundation deeper, which means that the first floor will be lowered.

Laying out utilities and creating a shock-absorbing cushion

Next, they begin to arrange a shock-absorbing cushion about 15 cm thick from gravel or crushed stone with fractions of 20-40 mm in size. The base is filled with fine sand, which is compacted every 20 cm with a hand tamper or vibrator until the design mark is reached.

All utilities must be laid before creating a monolithic foundation, so they are placed on a sand cushion with compaction according to the wiring plan below the freezing level. All ends of the pipes must be brought to the surface for further connection of the system. To increase the maintainability of networks, it is better to lay pipes in cases of larger diameter. For the sewer system, a well should be provided outside so that sewer inspection and repair can be carried out.

All existing pipes from under the foundation must be brought to the surface for further connection of systems

Helpful advice! As a backup option in case of failure of the main communications, a duplication of the engineering system is created, which can be switched to when repairing the old one.

After laying all utilities, the surface is covered with a small layer of gravel up to 15 cm thick, followed by compaction. For good waterproofing, the base is covered with waterproof material. Here you can use both inexpensive roofing felt and more modern products. The canvases are laid with an overlap of 10 cm and the joints are sealed. The edges of the waterproofing material must protrude beyond the foundation by at least 15 cm.

Installation of a thermal insulation layer for a USHP foundation

Insulation of the foundation is an important measure, thanks to which heat does not escape from the building into the ground, and cold does not penetrate from the soil into the room. The insulation must have high strength. Therefore, in USP technology it is recommended to use slabs made of extruded polystyrene foam, which (due to the presence of graphite in their composition) are characterized by increased compressive strength.

Helpful advice! Expanded polystyrene can harbor ants and other insects. Therefore, the material needs additional protection. Here it is recommended to use broken glass, metal mesh or ceramic foam slabs.

Extruded polystyrene foam slabs for the blind area were laid and covered with film

The material in the form of slabs 10 cm thick must be laid in two layers. The first should cover the entire perimeter of the base and the blind area. The second layer should be laid offset from the edge by at least 45 cm, which will create stiffening ribs. In the middle of the slab, in the thermal insulation layer, grooves 20-30 cm wide are made for future load-bearing walls, under which the insulation does not fit.

When using flat sheets of insulating material, special plastic nails with wide heads are used to fasten them. The contact points can be treated with an adhesive composition. It is recommended to arrange the elements in a checkerboard pattern, which will help to avoid the formation of cold bridges at their junction points. You can also use l blocks for USHP, which are mounted at the ends of the structure. Having a special design, they do not require additional fastening during installation.

Which insulation is better to choose for the foundation?

Today, the construction market offers a wide range of insulation materials from the well-known Stirex, Technoplex, Penoplex and URSA. The PSB-S material is not suitable for these works, since it is produced without a pressing stage.

The thickness of the foundation insulation is determined by many different factors.

Among all the proposed options, extruded polystyrene foam Penoplex occupies a leading position. The cost of the product is 1200 rubles/pack. The material is characterized by a number of distinctive advantages:

durability;
multifunctionality, since it simultaneously creates hydro- and thermal insulation;
environmental safety;
increased resistance to moisture;
not prone to the emergence of various microorganisms in the thickness of the layer.

Also no less popular is the insulation for USHP TechnoNIKOL. The material does not absorb moisture, does not shrink, does not swell, is characterized by a low thermal conductivity coefficient, exhibits chemical resistance and does not rot. To produce extruded polystyrene foam, TechnoNIKOL uses nano-sized carbohydrate particles, which increases the strength of the material, reducing its thermal conductivity, thereby increasing energy efficiency.

Insulating the foundation is a very important task, therefore, when choosing a suitable material, it is necessary to take into account its characteristics

The material is characterized by high compressive strength and stable thickness under load, as a result of which it can be used for loaded structures. You can buy the material from 1400 rubles/pack, the cost of l blocks for USP is on average 1300 rubles/pack.

At this stage, wooden formwork is laid under the future monolithic tile. To do this, racks are mounted to which the edged boards are attached using self-tapping screws and a screwdriver. The wooden frame is additionally reinforced with braces to give the structure greater strength. The formwork is lined with heat-insulating material from the inside. After the slab has gained sufficient strength, the fence is dismantled, and the insulation remains as protective sides for the lower part of the building.

The value of a double layer of thermal insulation and a heated floor system for a home at USHP

Due to the fact that USHP technology requires laying thermal insulation material in two layers, all the heat will remain in the house. The first layer of 10 cm along the entire perimeter of the base prevents the penetration of moisture. Another 10 cm of thermal insulation creates a good barrier against the cold that comes from the ground.

Since the heated floor is poured into concrete, the monolithic slab serves as an excellent heat accumulator

Thanks to the underfloor heating system, which is installed in separate circuits in each room, uniform heat distribution in the room is ensured and climate zones are adjusted. If you create the necessary insulation of the walls and roof of the building, it will be enough to maintain the temperature in the heating system no more than 28 degrees, which corresponds to the temperature of the circulating fluid (31-32 degrees), in order to create a comfortable microclimate in the house. However, this also depends on the finishing floor covering. Such measures will provide an additional benefit when using low temperature heat sources such as gas condensing boilers and heat pumps.

Thanks to the foundation in the form of a warm Swedish stove, you can save about 30% on heating. This is possible due to the fact that the underfloor heating system heats the concrete slab, and the concrete accumulates heat into the room. The thermal conductivity coefficient is 0.17 W/m²K, and for non-insulated concrete bases it is 0.4 W/m²K.

Laying insulation for the foundation

After the horizontal level of the base of the insulated Swedish slab has been brought back to normal, we can begin laying extruded polystyrene foam, which is characterized by increased resistance to vertical loads, water and steam. In our case, according to the technology used when constructing the USHP foundation, we lay extruded polystyrene foam of the TechnoNIKOL brand in those places where there will be the greatest load, that is, as a base for external walls and load-bearing partitions. For the rest of the foundation of the insulated Swedish slab, we use high-strength polystyrene foam (expanded polystyrene):

Since the construction of the USP foundation is done with our own hands, we need to cut both the foam and polystyrene foam ourselves. To do this, we can use the simplest device in the form of a heated string, the so-called “thermal cutter”. The principle of its operation is quite simple and reliable. To set it up we need:

a transformer on which the power of the electric current could be regulated;
metal string;
two string clamps with the ability to adjust their tension:

A thermal cutter made on your own is installed on a work surface - a table, workbench or other horizontal object. Typically, the size of the working surface is set based on the size of the foam or polystyrene board. After we have cut the insulation boards into the necessary elements and given them the required dimensions, we begin to assemble the insulated part of the USHP foundation, the so-called “trough”:

The connection of polystyrene foam to each other must be done with a special glue designed exclusively for working with polystyrene foam. This glue can be purchased at any construction market or at a specialized construction store. Externally, the glue looks the same as polyurethane foam in a large container and comes in two types - professional and regular, which can be recognized by the plastic tube attached to the container. This type of glue is convenient in cases where you need to connect something in a small amount, after which the composition will no longer be needed.

As for professional foam, for it you will have to additionally purchase a special gun into which the cylinder itself is inserted directly. It is made of metal, and with proper care it can be used for quite a long time, using more than one foam container:

Do not forget that when using adhesive foam, there is very little time for gluing. That is, at the moment when we squeeze out the glue, we must know exactly where we will glue the part on which the glue is already applied. There are 2 hours before the seam is completely dry, but there are only 15 minutes to adjust the joint.

As for the shape of the insulating elements made of polystyrene foam, we produce an L-shaped profile. We assemble our polystyrene foam “constructor” for the insulated Swedish stove, gluing all the parts with glue and connecting them together with special plastic screws that look like disc-shaped dowels, specially designed for this work:

After installing the first insulating layer, we cover the entire surface around the perimeter with plastic film. The film thickness should be 150-200 microns. We separate the layers of polystyrene foam, as shown in the photo of the foundation:

Reinforcement of the Swedish slab foundation and installation of heated floors

Foundation reinforcement is performed to allow the structure to absorb tensile loads. The technology is performed according to the following scheme:

creation of stiffening ribs for the grillage: frames are laid from reinforcement 10-16 mm thick, connected with rectangular clamps 6-8 mm in increments of 300 mm, taking into account the protective layer of concrete;

Cutting reinforcement for USHP foundation

slab reinforcement: installation between the stiffeners of two reinforcing mesh with cells 150x150 mm from rods 10-14 mm thick, cell width 15 cm with tying structural elements with twisted wire every 25-30 cm.

The thickness of the rods is selected taking into account structural, snow and operational loads on the surface. Utilities should not be installed in stiffeners. In order not to damage the insulation, it is recommended to assemble the spatial reinforcement frame separately, and then you need to lay it ready-made on special clamps in the grillage area where the frames are connected to each other. The mesh for the slab is tied on site. The lower structure is installed on PVC clamps.

The technology of the Swedish insulated slab involves the installation of a heated floor in the thickness of a monolithic foundation. The heated floor contour is laid on the upper mesh and secured with nylon clamps. In this regard, the thickness of the upper protective layer of concrete should be taken into account, which should be 50-70 mm. In places where load-bearing walls or doorways are located, pipes should be placed in sleeves made of durable material. There must be a distance of at least 10 cm between the pipes.

It is better to fasten the reinforcement with a special gun

If the laying is more dense, this will not affect the efficiency, but will result in excess consumption of material. A distance exceeding 25 cm will impair the uniform distribution of heat over the surface. Near the walls, pipes must be placed more densely than in the central part of future premises. An indentation of about 15 cm should be made from the wall.

Important! The heating pipes of a water heated floor should be arranged in an insulated circuit for each room separately, which will allow each room to be heated independently of the others.

The distribution elements of the system are brought up and fixed on rods hammered vertically. The collector should be located in the place provided for by the design at a given height. To install it, four reinforcing bars 1.5 m long are driven into the foundation. A board is fixed to them and the collector is temporarily fixed. Heated floor pipes are connected to it. Where flexible pipes rise to the collector, they must be protected using a special corrugated pipe.

Important! The heating system must be tested for leaks by filling it with coolant.

In a USHP foundation, the entire area is covered with welded reinforcing mesh, and reinforcement bars are used in the stiffeners

Do-it-yourself USHP foundation reinforcement

When our polystyrene foam “trough” is ready, we can proceed, according to technology, to constructing a reinforcing layer, which also includes stiffening ribs. Stiffening ribs are the places on which the load-bearing walls and internal partitions of the house rest. Particular attention must be paid to the quantity and thickness of reinforcement:

In our case, we are making a stiffening rib 45 cm wide, for which we lay periodic profile reinforcement in the shape of a rectangle, two rods on the bottom, two on top, laying connecting steel rods across at certain intervals:

Next, in the places where the rods join, we tie them together using annealed knitting wire and a special hook, and if it is not available, pliers or pliers. Two or more reinforcing bars are pulled together as shown in the following photo of the device for a slab foundation:

It is advisable to further strengthen the corner joints, for which we bend a piece of reinforcement 80-100 cm long at an angle of 90 degrees and get an L-shaped piece. With this L-shaped element we connect the corners, the places where the reinforcing bars and vertical parts are joined, connecting all the elements into a single reinforcement frame:

To properly make a UHP foundation, we install clamps along the entire length of the reinforcing bars, also bent from reinforcement, the distance between them should be 50-70 cm:

We also connect all the intersections of the reinforcement with tying wire.

As the above work is completed, a metal frame is obtained. The entire structure should be slightly raised above the last layer of polystyrene foam using plastic “chairs” so that the subsequently poured layer of concrete will protect the metal from corrosion caused by exposure to an external humid environment. Also, the reinforcing belt should not come into contact with the vertical part of the polystyrene foam; this can be achieved using plastic stars that create the necessary gap.

After the reinforcement frame is ready, using the technology of constructing a USP foundation, we cover the upper part over the entire area of the foundation with a welded metal mesh VR, with a pitch of 10x10 cm. The mesh should also be raised on plastic chairs. After all the work has been done, you can attach the water-heated floor pipes to the welded mesh:

If we are installing a heated floor, then upon completion of the work, a welded mesh is laid again on top of the heated floor pipe, and it should also rest on plastic chairs of higher height.

USHP foundation: foundation concreting technology

The final stage of installing an insulated foundation slab is pouring the base with concrete mortar. The important thing here is to do the process one time. To do this, you can use a concrete mixer truck with an installed concrete pump. The solution is evenly distributed over the surface using shovels and trowels. To obtain a uniform surface, the fill should not spread over a distance of more than 1.5 m in diameter.

Batch filling can be done at intervals of 1 hour. If it is necessary to interrupt for a longer period of time, work seams should be arranged. After resuming work, they are moistened with water and treated with a cement laitance primer. The solution should be compacted using a vibrating plate or deep vibrator.

To ensure that the final surface is smooth, the base is sanded. This is an important undertaking because the concrete slab is the floor of the first floor. Otherwise, you will have to spend additional money on a leveling screed.

Helpful advice! It is recommended to build a USP foundation at the end of summer, when the groundwater level drops.

The work on the USP foundation is being completed by pouring concrete and grouting/grinding it

During the hardening period of the base, proper care of the concrete surface should be provided. In hot weather, it is necessary to moisten the foundation and cover it from precipitation with plastic film. Stripping can be carried out after 48 hours at a temperature of 30 degrees, and after 5-7 days - in cold weather at a temperature of 10-12 degrees.

Application

The key feature of USHP is rigidity. That is why the structure can withstand ground movement very well. It has become a good option for the construction of low-rise buildings in areas where there is:

high groundwater level;
sandy and loose soil;
swollen and moving earth.

The insulation under the Swedish stove prevents soil freezing. Therefore, residents of the northern regions do not have to worry about the rapid deformation of the foundation during the operation of a residential building.