IN low-rise construction you can do without pouring a monolithic concrete foundation and create a reliable, warm foundation for the future building. This opportunity is provided by foundations made using technology USP.
The abbreviation stands for insulated Swedish stove, which is effectively used in European countries. The technology became known in Russia since 2009, but is currently not widely used - developers are just beginning to master it.
The lack of interest is caused by the lack of complete and reliable information about this type of foundation. At first glance, the technology seems complex and expensive. In fact, the cost of the work turns out to be lower than pouring a conventional monolithic concrete slab.
Structure of an insulated Swedish plate
The data in the article is purely informative and does not constitute instructions for arranging a USP foundation: it requires precise engineering calculations, which are tied to a specific building site.
There are several arrangement options, but the differences are personal in nature and do not affect the overall installation technology. In essence, the Swedish foundation resembles a multi-layered cake consisting of the following elements:
soil base with a pre-prepared drainage system;
geotextile substrates;
sand and gravel pads with areas for sewer pipes and utilities;
insulation layer;
waterproofing;
second layer of insulation;
piping made of reinforcement and underfloor heating systems;
concrete slab (average thickness 100 mm);
floor finishing.
At first glance, the design seems bulky and complex, but this is an illusion. All work can be done on your own without the use of heavy construction equipment.
Provided that the work is carried out correctly at all stages, a solid foundation is obtained, with stiffening ribs and a properly installed heating system. This design completely prevents possible heat loss and at the same time has a high load-bearing capacity.
Advantages and disadvantages
|
Pipes do not require additional insulation. Reliable protection from groundwater exposure. Possibility of building a foundation on all types of soil, except rocky. Reduced heating costs due to the “warm floor” system. You can do without the use of bulky construction equipment. Acceleration of the process - the full cycle from preparing the base to finishing takes no more than two weeks. Uniform load distribution, resistance to deformation. |
Inability to eliminate errors made during the construction process. The need for backup communications. There is no possibility to make a basement and ground floor. |
Some of the shortcomings can be eliminated if you entrust the work to qualified designers and workers. However, attracting specialists makes the financial benefits less attractive.
USP or monolithic foundation?
At first glance, the economic benefit when arranging a USP is invisible - it is required large number building materials that cost a certain amount of money. The estimate includes the purchase of:
insulation;
fittings;
floor insulation systems;
other materials.
When pouring a monolithic foundation, such expenses are not required: the base is prepared, reinforcement is purchased, piping is done and concrete is poured. However, the financial benefits of pouring a monolith are understandable only to non-professionals.
Such a foundation can be compared to a bank loan: there are not enough funds - fill the site, and then gradually build further. The process turns out to be extended over time, which implies an increase in the price of building materials. In addition, the monolithic foundation needs insulation and waterproofing; utilities will also be supplied to the building.
USP is suitable for people who understand the benefits of such a design and are building a house that will be warm and cozy regardless of the vagaries of the weather. If you make calculations on energy savings for 10 years forward, the attractiveness of an insulated foundation will increase. Against this background, a monolithic foundation looks like an ordinary slab, which requires additional investment.
Step-by-step technology for arranging USP
The work process begins with the involvement of technical specialists who can calculate the bearing capacity of the soil, the likelihood of shifting layers and the capabilities of the drainage system. After this, the construction of the foundation is carried out in a certain sequence.
The Swedish foundation is never laid on a fertile layer of soil: this is guaranteed to lead to a shift in the structure during the construction of the building. Therefore, such a layer of soil is completely removed from the construction site.
The pit is made shallow: usually 2-3 bayonet shovels, however, its external dimensions should extend one meter beyond the boundaries of the walls of the future building. The bottom of the pit is lined with geotextiles with the substrate running onto the side walls.
Storm drainage and groundwater drainage are necessary to ensure a dry foundation. For these purposes, geotextiles are covered with a layer of crushed stone, and an underground reservoir is made with pipes connected to it. To lay the drainage system along the perimeter of the pit, trenches are formed with a slope towards the main well.
Utility lines
The next stage is the installation of water supply and sewerage pipes. Communications must be buried below the ground freezing mark in winter.
In addition, it is necessary to plan in advance the location of the risers in the house, to bring the pipes outside for connection to centralized or autonomous water supply systems.
Considering the shortcomings of USP, it makes sense to immediately duplicate the communication system in order to use reserves in case of a malfunction. At this stage, a sand cushion is added, which is necessarily compacted with a tamping machine.
The first layer covers the entire perimeter of the pit.
The second one retreats by 40-45 cm inside.
This is necessary in order to install along the edges L-shaped modules made of polystyrene foam for external contour.
At this stage, the installation of the “warm floor” system is carried out with the installation of collectors and temporary pressure testing of pipes. Next, a two-layer reinforcing belt is made from reinforcement with a diameter 12-16 mm. Recommended grid pitch 15*15 cm.
Manufacturing of formwork
For this they can be used L-shaped modules expanded polystyrene, reinforced on the outside with boards and spacers to prevent them from being squeezed out under the action of the concrete mass. The classic version can also be used: an internal frame made from panels of thick plywood. The height of the formwork is calculated based on the following values: insulation thickness (20-30cm) and the slab itself (no more than 10 cm).
This stage is no different from arranging a monolithic foundation. The concrete mixture is supplied continuously to prevent the formation of joints and is necessarily compacted with deep vibrators to uniformly fill the internal space.
Keep in mind that contact of the vibrator with “warm floor” pipes or reinforcing mesh is extremely undesirable.
Formwork can be removed after 72 hours after filling. If work is carried out in hot weather, the slab is covered with burlap or plastic film and periodically moistened with water. In winter, a heating system is installed before pouring.
This publication will be devoted to the technology of creating a UWB foundation. This abbreviation hides the name “insulated Swedish stove” - one of the relative novelties in the practice of Russian private construction. Such foundations fit perfectly into modern trend maximum energy saving, which, of course, is the future of the entire construction industry.
Insulated Swedish stoves have not yet become widespread in our area, but, apparently, to a large extent simply due to the lack of information about them. However, many construction companies This technology has already been adopted and used in various regions of the country. Despite some differences in the nuances of execution, general principle maintained uniform - it is a thermally insulated monolithic reinforced concrete slab with utilities already laid in its thickness and a water heating system for the floor of the first floor.
It should be said right away that this publication should not be considered as instructions for self-construction such a slab. This stage of construction must necessarily be based on professional engineering calculations, and its execution requires the use of special equipment, that is, appropriate qualifications of craftsmen. Therefore, the USP foundation technology will be given in an overview so that the reader can form a clear idea of it, as well as the advantages and disadvantages of such a foundation for their own home.
Why do you need a foundation like an insulated Swedish slab?
Anyone who follows the latest scientific and technological progress can see that in almost all spheres of human activity there is a desire to reduce as much as possible the dependence on non-renewable energy sources - solid fuel, oil and natural gas. This trend has closely affected the construction industry.
Already in our time, in many countries, at the legislative level, the issue of constructing buildings with a degree of energy efficiency not lower than the “passive house” category is being resolved. Due to the peculiarities of their design, rational location on the ground, and equipped with modern engineering equipment, such buildings are characterized by extremely low external energy consumption, while providing comfortable living conditions for people.
Cement prices
According to existing European standards, a “passive house” must, in order to create optimal conditions residence consume no more than 15 kWh per square meter of area per year. If we compare it with old houses, in which this figure reached 300 kWh, and even new buildings, already classified as low-consumption buildings (60 kWh), then the difference is more than significant.
The very concept of “passivity” in this case implies that the building itself does not generate the necessary energy to fully support life. That is, the main emphasis is not on the saturation of complex equipment, but on planning solutions, architectural features. Such a house should absorb, accumulate incoming energy to the maximum extent and use it as efficiently as possible.
It is easy to understand that the problems of maximum thermal insulation of a residential building necessarily come to the fore, and of all structures without exception that can at least to some extent become a conductor of cold. And one of the main ways of heat loss is always the foundation and floor of the first floor. And a USHP-type foundation fits perfectly into this concept of a “passive house” with a minimum level of energy consumption.
It is interesting that the concept of “Swedish” is very arbitrary and does not reflect the history of the emergence and development of this technology. The first experiments on the use of such foundations were carried out at the beginning of the 20th century, not even in Europe, but overseas, in the USA. With the development of technologies for the production of durable and highly effective insulating materials, this method began to be widely practiced in the Old World, and here again it is not the Swedes, but the Germans who claim the palm. Most likely, this name comes from the fact that such foundations are very widely practiced in Northern Europe, Scandinavia and Sweden - in particular, which is not surprising, given the severity of the winter climate there. In addition, many high-quality thermal insulation materials used in this type of concrete foundations for houses are produced in Sweden.
However, that's all - " lyrical digressions“, and it’s time to move on to considering the very structure of this very “insulated Swedish stove”.
The basic structure of the “insulated Swedish stove”
If you look at many examples of the construction of USP, you will notice some differences in approaches. However, all of them are not so significant, and the basic principle of the structure of this unusual foundation always remains the same.
In fact, as the name suggests, such a foundation is more of a slab foundation, that is, the load from the building is distributed over its entire area. True, a kind of “symbiosis” with the strip structure can be traced - under all walls, both external and internal, there are always reinforcing thickenings like a standard “tape” - builders call them stiffening ribs.
The main “highlight” is something else – this entire monolithic structure is necessarily based on a high-quality insulated base. Moreover, the stove itself performs an active function of ensuring an optimal microclimate in the premises, since a water heating circuit is embedded in its thickness.
The illustration below shows one of the options for an “insulated” Swedish stove - using this diagram it will be easier to understand its basic structure.
So, let's start to figure it out.
USHP does not require deep installation. The top fertile layer is removed from the soil (item 1), a pit is dug and carefully leveled, the depth of which depends on the type and condition of the soil on the building site. A characteristic feature is that this excavated area for the foundation itself must certainly extend to the belt of blind areas around the perimeter of the future house. Insulated blind areas are one of the mandatory features of this scheme.
The excavated area is completely covered with a layer of geotextile (item 2) - this will create additional “reinforcement” of the base, which is especially important on complex, not completely stable soils.
Another prerequisite for the stability and reliability of the USP is the presence of a ring drainage system around the perimeter of the foundation. It is necessary to completely eliminate the possibility of frost heaving of the soil under the slab, given that its laying is shallow, almost always above the freezing level. The drainage system includes a set of trenches in which drainage pipes (item 4) are laid, covered with a layer of gravel (item 3), converging to wells located in the corners or in other places, in accordance with the design.
The site drainage system is something that many people simply forget about!
A frivolous attitude towards measures to remove excess moisture from the site often leads to very sad consequences. To avoid this, it is necessary to think through and implement a drainage system in practice. Such a task is very difficult and time-consuming. But we hope that a special publication on our portal will help the reader understand all the intricacies of this problem.
The stability of the USHP slab is also ensured by the fact that it is “based” on a powerful and very carefully compacted “cushion” of sand and gravel (crushed stone). This layer (item 5), in essence, replaces unstable soil and creates a reliable foundation that is not prone to swelling, subsidence and other deformation phenomena. The thickness of this “cushion”, as well as the sequence of sand and gravel layers, must be determined at the design stage of the USP and directly depend on the characteristics of the area and on the specifics of the building planned to be erected on this foundation.
Even at the stage of digging a pit and creating a sand “cushion”, the necessary utilities are immediately laid. This illustration shows a sewer pipe (item 6) with inlet pipes at the required points of the future house (item 7), and then leading to a septic tank, central sewer system or local treatment facilities.
It must be said that a pre-laid utility system may not be limited to sewerage only. Often, at the same stage of work, the introduction and distribution of power supply cables for the house, water supply pipes from an autonomous source, and even their distribution to future premises are immediately provided for.
The next mandatory element of the system is no less than a 100 mm layer of insulation - high-strength extruded polystyrene foam (item 8). It can be laid directly on a sand and gravel “cushion”, or another layer of geotextile can be laid underneath it - extra reinforcement will never hurt. Thus, the slab receives reliable continuous protection from cold penetration from below.
But such thermal insulation would not be effective if we did not take into account a few more the most important nuances. The first of them is the protection of the end part of the USHP with the same layer of EPS (item 9). The same blocks can be used for this, but some manufacturers produce special L-shaped modules designed specifically for these purposes.
Prices for geotextiles
geotextiles
Many of these modules immediately have an external coating of glass-magnesite or asbestos-cement sheets, which become an excellent basis for the future finishing of the building’s basement (item 10).
The next nuance is that without any break with the general thermal insulation layer, the insulation belt is also covered over the entire width of the future blind area (item 11). This is an extremely important condition: due to the shallow location of the slab, no paths for cold penetration under it should be left in order to avoid frost deformations of the base. The only difference from the general insulation layer is that this belt is made with a slight slope outward, in order to avoid the accumulation of rain or melt water. And in the future, the owners are free to create blind areas (item 12) at their own discretion.
Properly executed blind areas are the key to the longevity of the house
This element of the building’s design performs not only and not so much a decorative role. Its main task is to prevent destructive processes along the external contour of the foundation of the building. What are there, and how to make them yourself - read in a special publication on our portal.
In order to prevent water leakage from the solution when pouring the slab, as well as for additional waterproofing from below, it is recommended to cover the first continuous layer of insulation with waterproofing material (item 13). This role can be played by a film or roofing felt with “cold” gluing of the overlap of adjacent strips.
Next, the next layer of insulation is laid out - EPPS (item 14). But now it is installed only in the area of the planned premises of the house. Thus, in the locations of future external walls and internal partitions, original “channels” are formed, which, after pouring concrete, will become the very “ribbons” - stiffening ribs on which the building will be erected.
The thickness of this insulation layer can vary - from 100 to 200 or even more millimeters. This depends on several factors. Here, both the climatic characteristics of the region and the required thickness of the created stiffeners, which, in turn, depends on the material of construction of the building walls, are also important. All this is determined at the USP design stage.
A reinforcing grid is laid on top of the laid insulation (item 15). And in the places where the stiffeners are located, a more complex volumetric reinforcing structure is linked (item 16), similar in structure and installation principles to the reinforcing belt of a strip foundation.
And now here is the “highlight” of the USP - the laid out reinforcing mesh becomes the basis for laying the concrete slab (item 17). Here, of course, the basic principles of installing a warm water floor are preserved, but the calculated indicators of such a heating system may still differ from the usual one. Laying of contours is carried out immediately in all future rooms of the first floor, in accordance with the developed project. Naturally, it is necessary immediately, even at the design stage, to decide on the location of the collector - it must also be installed at this stage of work.
With the necessary surface treatment, the poured slab is a completely finished thermally insulated and heated base for laying almost any type of finishing floor covering (item 19).
After the USP is completely ready, you can proceed to the construction of the walls of the building (pos. 20). As a rule, heavy materials are not used for these purposes - wooden, frame structures or walls made of light gas silicate blocks are more often used (as shown in the illustration). It is probably unnecessary to say that in order to achieve energy efficiency of a building, its external walls must also have a reliable one (pos. 21), which is then hidden by one or another external façade finish (pos. 22).
This was a general standard diagram of 2 insulated Swedish stoves.” Now let's evaluate all its pros and contras.
Main advantages and disadvantages of USP
What is attractive about the “insulated Swedish stove”?
Pure supporters of the USHP foundation are constantly growing. This is easily explained by a number of advantages that the use of such an innovative building framework provides.
- The USHP design can be installed on almost any soil where construction is generally possible. The shallow location of the slab is fully compensated by replacing the soil with a powerful, tightly compacted sand and gravel cushion, reinforcing the topping layers with geotextiles, the presence of a ring drainage system and high-quality insulated blind areas. If the project is calculated and drawn up correctly, then the likelihood of signs of frost swelling is reduced to almost zero.
A direct confirmation of this is the active use of USP in the Scandinavian countries, where the combination of high soil moisture and harsh winter conditions makes the construction of reliable foundations a very difficult task.
- Not only does reliable insulation virtually eliminate heat loss through the floor. The stove itself becomes a powerful heat accumulator, obtained from the extended “warm floor” pipes, which fits perfectly into the “passive house” concept already mentioned above. Even if there is a sufficiently long break in the operation of the heating system in the premises of the building, it will be maintained comfortable temperature. And with stable heating, energy costs are reduced by almost a third.
This is of particular importance for. Such buildings, although they have high-quality thermal insulation, still do not have the proper level of heat capacity, simply due to the peculiarities of their design, that is, they are unable to effectively accumulate and release heat. This deficiency will be fully compensated by USP.
- A high-quality Swedish slab is a finished floor for residential and utility rooms house, which all that remains is to cover it with one or another finishing coating.
- With the full construction of the USHP, the homeowner, in addition to the finished heated floor, immediately receives the necessary engineering communications systems, ring drainage around his house, and insulated blind areas.
If we evaluate all these works in total, both in terms of completion time and in terms of their total cost, then there is a very significant benefit. In general, the construction of a USP for a house of approximately 100 square meters by an experienced, well-coordinated team is estimated to take 7–10 days. It is clear that it is simply impossible to invest in such a period of time if all the above-mentioned building structural elements and supporting systems are created separately.
What do they say about the disadvantages of USP?
Such a foundation is not without some disadvantages. However, as will be clear later in the text, some of them can be attributed, rather, not to the “disadvantages”, but to the specific features of USP, some of which you will have to come to terms with, being content with the advantages of the foundation.
- First, USP cannot be considered as a “field for experimentation” or as an object for unqualified amateur activity. The design itself indicates that all work must be carried out in accordance with a pre-developed project, in which the linear parameters of both the building itself and all necessary systems and communications are determined precisely, literally down to millimeters.
But even this is probably not the main thing. It is simply impossible to independently analyze the condition of the soil on the site, assess the composition and thickness of the replacement sand and gravel backfill, plan the thickness of the insulation, the slab itself and stiffeners, and the thermal characteristics of water heating circuits without special knowledge and the necessary experience. The involvement of highly qualified designers is required, and to carry out construction and installation work it is better to invite a well-coordinated team with relevant work experience.
- In any case, the foundation is low. So lovers of houses with a high base will have to look for a different solution. The same reason imposes certain restrictions on the construction of USHP on rough terrain, with a large slope of the site. Creating such a slab on such a “building spot” can lead to unjustified overestimations of the overall estimate.
- A house on USHP does not have a basement or ground floor - this should be taken into account in advance.
- There are also restrictions on the very design of a house built on the basis of USP. So, this is most often a one-story building, with a maximum of attic space. To raise walls, lightweight materials are usually used - wood or gas silicate blocks. The already mentioned frame structures are widely used. But for brick or stone walls such a foundation may turn out to be rather weak - again, this will all be decided at the stage of comprehensive design of the future building.
- All main communications and systems are embedded in a concrete slab. This means that in case of any emergency situations access to repair and restoration work will be extremely difficult. This means that it is necessary immediately, even during installation, to carry it out with such high quality, and from such reliable materials, as to minimize the likelihood of such moments occurring.
- In general, increased demands are placed on the quality of all materials used for USP. Particularly in this regard, it is necessary to note the insulation - extruded polystyrene foam boards. It is completely unacceptable to use anything just for reasons of false economy. Not only do the XPS slabs have to withstand a very significant static load from the mass of the entire building. High-quality insulation should not be deformed, much less decompose under the influence of factors external environment. There is another danger - rodents can easily gnaw passages in polystyrene foam, which can lead to the appearance of areas of weakening of the entire USP as a whole. Therefore, it is recommended to use special types of XPS, developed and produced specifically for such structures.
A number of foreign manufacturers produce similar slabs, but Russian ones also have something to brag about. Especially for foundations, including for the “insulated Swedish slab,” TECHNONICOL company technologists have developed “CARBON ECO SP” polystyrene foam blocks.
Such insulating panels, due to the introduction of nanocarbon microparticles into the composition (which, by the way, gives the blocks a characteristic silvery tint), have received a number of additional advantages. Without losing their thermal insulation qualities, they are able to withstand increased loads without deformation, and a USP poured on top of such a layer is guaranteed to cope with distributed pressure reaching up to 20 t/m². Such insulation is bypassed by the mouse, that is, from this point of view it is completely protected. And clear geometric shapes and the presence of special connecting lamellas make laying the insulating layer extremely simple. The material is inert to possible chemical influences, has an enviable durability, estimated at no less than 50 years, and is completely harmless from an environmental point of view.
Prices for expanded polystyrene panels
expanded polystyrene panels
Approximate sequence of work during the construction of an “insulated Swedish stove”
During the course of the publication, it has been said more than once, and once again it is especially emphasized, that USP requires a highly professional approach both at the stage of designing the entire house as a whole, and at the stages of constructing the foundation. Therefore, the table below should not be considered as a “guide to action.” This is just an illustrated overview of the general sequence of actions when constructing such a slab. Nevertheless, it will be useful, at least from the point of view that the interested reader will get an idea of how and in what order the main operations for creating a USP should be performed.
| Illustration | Brief description of the operation performed |
|---|---|
 | It all starts, of course, with careful markings on the construction site. It is necessary to immediately outline the outline of the future pit, a pit for placing a septic tank (if it is provided for by the project), trenches for laying utilities - all in strict accordance with the developed project. |
 | Next comes excavation work. As already mentioned, the area of the pit usually immediately accommodates the blind area around the perimeter of the building. At this stage, it is quite possible to involve heavy earth-moving equipment - although the pit is not so deep, but given the large area, the total amount of soil removed becomes very impressive. |
 | However, there will also be plenty of manual work - the edges of the pit, one way or another, will have to be “ennobled” with shovels. |
 | After digging the pit, it is necessary to mark again - this time for the pipes being laid - drainage, sewer and, possibly, water supply. In addition, often at this stage the power cable is also laid immediately if underground wiring is planned. The illustration also shows a pit for septic tank equipment. |
 | This is how the utility system hidden by the slab will look like in this project. |
 | The pit has been dug. Please note that the power cable has already been inserted into it through the external trench. |
 | It is not always convenient to dig trenches specifically for pipes. Usually they do this - a primary layer of sand or sand-gravel mixture is scattered at the bottom of the pit and compacted (this, of course, should be taken into account when calculating the depth of soil removal). This is followed by laying out the pipes in accordance with the project. Horizontal pipe connections are closed with plugs to prevent sand, soil or other debris from getting into them. The pipes are laid with the slope necessary for the free movement of sewage. Using the same principle (only without observing the obligatory slope), plumbing can be immediately installed in the future premises of the house. |
 | At the same stage, a ring surface drainage is installed - the trenches under it are lined with geotextiles, and then drainage pipes are placed in them in a layer of crushed stone, connected to the wells. |
 | Now you can cover the primary “cushion” with geotextile - this will become a kind of reinforcement for the preparatory replacement sand layer. An already installed drainage well is clearly visible in the background of the illustration. |
 | The creation of the sand cushion continues, but on top of the geotextile “pad”. The sand is evenly distributed first using shovels. |
 | This operation is very labor-intensive, but necessary. Gradually, a layer of sand hides all laid utility lines - only the left horizontal pipes and cable outlets remain visible. |
 | Each poured layer of sand (or gravel) must be compacted very carefully. There is no need to even think about doing this manually - a special vibrating plate is used. |
 | Of course, when tamping, it is necessary to constantly monitor the level of the created “cushion” and its compliance with the horizontal plane. This illustration shows that for the sand fill, mini-formwork was built around the perimeter of the pit, which both prevents spillage at the edges and sets the upper level of the compacted fill. In addition, beacons made of even boards are visible, which are placed on stakes strictly according to the level. However, different craftsmen may have other methods of controlling the horizontality of the sand “pillow” and its planned height |
 | This is what the finished sand cushion looks like after the compaction operation is completed. All protruding ends of utilities - pipes and cables - are clearly shown. |
 | It is necessary to make a small remark. The point is that in various sources The structure and sequence of creation of these replacement “pillow” layers may differ. An example was shown above where only clean sand was used. However, gravel or crushed stone often becomes the “starting” layer - this is motivated by the fact that on wet soils there is a need to reduce the likelihood of capillary upward spread of moisture. And only after compacting the first gravel layer do they move on to sand backfill. There is also a diametrically opposite solution - they start with sand, and gravel is poured directly under the insulating belt on which the USP is based. It is difficult, being unfamiliar with the intricacies of construction, to choose the right optimal location and the thickness of the layers - but this is just another argument that the design of such foundations should be carried out professionally. But in any case, no matter how the layers of the “pillow” are alternated, each of them must be compacted as thoroughly as possible. |
 | When the “pillows” are ready, they move on to laying the first thermal insulation layer. They usually start with vertical walls around the perimeter, framing the foundation of the future house. They will also play the role of formwork when pouring the slab itself. This illustration shows how vertical walls made from standard EPS panels are installed. |
 | However, as mentioned above, it is much more convenient to use special L-blocks, which immediately form the angle of transition from the vertical wall to the horizontal insulation belt. They are equipped with a system of locks that ensure tight joining with each other and with horizontal panels. In addition, a panel is attached to their outer surface, facilitating further finishing of the basement part of the foundation. |
 | L-modules are placed along the lines of the external markings of the foundation and joined together. |
 | To avoid even the slightest displacement, a centering groove is provided on top at the junction of the two modules, into which a special liner is inserted. |
 | And on the horizontally located shelf of the module, a reliable connection is ensured by the use of special mounting metal plates with spikes. These plates are simply pressed with your foot along the connection line of adjacent modules - now they are securely connected to each other, and their displacement is excluded. |
 | With well-done markings, the creation of an external insulation contour of the USP using L-modules is carried out very quickly. |
 | No additional devices or tools are required - a couple of workers will quickly cope with this task. |
 | After laying the outer border of the “insulated Swedish slab”, they proceed to the final laying of the first continuous layer of thermal insulation. |
 | EPS boards are also easy to adjust - due to the lamellas at their ends, they are precisely joined, without leaving through seams. If it is necessary to adjust the slab to the desired size, it can be easily cut with a hacksaw or even a sharp construction knife. |
 | For the passage of pipes or cables, appropriate openings are cut out in the slabs. |
 | They try to fit the slabs as accurately as possible to prevent leaving even small gaps. If gaps cannot be completely avoided, they are completely filled with polyurethane foam. |
 | After laying a continuous layer of insulation, markings are carried out again. Now the main task is to outline the areas where stiffeners will be created, that is, on which the second (and, if necessary, third) layer of thermal insulation will not be laid. |
 | Next comes the stage of laying the second (third) layer of thermal insulation boards. As a result, “channels” are formed, which will be determined by the stiffening ribs of the USP after concrete is poured. This illustration clearly shows what kind of picture is obtained when using one layer of continuous thermal insulation, and two layers in the rooms of the future house, between the stiffeners. |
 | The next important stage of work is the creation of a reinforcing belt for the future slab. For the stiffening ribs, reinforcing frame structures are knitted, similar to those used in strip foundations. As a rule, such frames are knitted to the side, and then laid in place. The dimensions and number of rods of this design are based on the design results. |
 | The frame reinforcing structure is laid in the “channel” of the stiffener. From below it rests on stands, which creates the necessary gap so that the armored belt is in the center of the resulting “ribbon”. Pay attention to one more nuance. Although extruded polystyrene foam has sufficient rigidity, it may not be able to fully cope with the formwork function - there is a high risk of fracture under the pressure of the concrete solution being poured. Therefore, an additional wooden structure is mounted around the created “side”, which is reinforced with wedges and oblique supports - the same as when pouring a conventional strip foundation. |
 | After laying the belts along the stiffening ribs, a lattice reinforcing structure is knitted over the entire remaining area from rods or using ready-made cards. In any case, the reinforcement structures are linked to each other. Special supplies are also placed under the grating so that it is approximately 40 mm from the lower edge of the concrete slab being poured. |
 | Once the entire reinforcing structure is ready, they proceed to the installation of water heating circuits for the slab. First of all, a distribution manifold is installed in the place provided for in the project. It is usually placed on two fixed metal profiles, which, after pouring the slab, will become stationary racks of the manifold cabinet. |
 | For laying circuits, only high-quality pipes are used, suitable for many years of trouble-free operation. Typically, pipes made from cross-linked polyethylene PE-HA are purchased for such purposes - this is the best option. It is probably unnecessary to explain that false economy on these materials is completely unacceptable. |
 | The pipes are laid out in the future premises of the house in strict accordance with the previously developed project. The ends of the circuits are brought to the installation site of the collector. |
 | The pipes are fixed to the reinforcement grid using conventional nylon clamps. |
 | After installing the circuits and connecting them to the collector, the installed system must be pressure tested. To do this, it is filled with coolant and test pressure is created. The pressure gauge monitors that the pressure remains at a given level. Its fall will indicate that there is a leak somewhere - it will be necessary to identify and eliminate the defect. |
 | After testing, the pressure in the system is not released - it is necessary to prevent pipe deformation when pouring concrete into the slab. In fact, everything is ready for pouring - all that remains is to wrap the collector and vulnerable points of the outgoing communications with film so as not to splash them with the solution. |
 | The USP, to ensure solidity, should ideally be poured in one go. And this means that required quantity the mortar will have to be ordered and then distributed using a concrete pump. |
 | The solution is distributed first with shovels, then with a rule, so as to reach the specified level of slab thickness. |
 | However, the usual distribution of concrete in this case may not be enough, since it is absolutely unacceptable to leave even the slightest possibility of the presence of voids and uncompacted mortar. For high-quality pouring, a deep vibrator is used, which ensures that all voids and cavities are filled with concrete, and to level the surface of the slab, the optimal solution is to use a vibrating screed. |
 | After pouring, the main stage of work on creating the USP can be considered completed - within the time period established by the technology, the concrete will reach the required maturity, it will be possible to remove the formwork, relieve the pressure in the pipe ducts and move on to the next stages of construction. However, since the resulting slab becomes, in fact, a finished floor, it makes sense to grout it and simultaneously harden it. To do this, after waiting for the initial setting of the solution (when the worker’s foot leaves a mark no more than 2-3 mm deep), they begin to grout the surface using a special installation, which builders often call a “helicopter”. At the same time, you can use one of the concrete hardeners - powder topping. |
 | As a result, the sanded slab will have a completely different appearance - perfectly smooth, dust-free, and ready for any further finishing operations. |
So, the result of the work - an insulated Swedish slab that has gained strength - is fully ready for further stages of construction. And at the same time, the owners already have a reliable foundation for the house with a drainage system, heated floors on the first floor, fully suitable for any finishing, and laid utility lines.
There is no doubt that such a foundation system will certainly become more widespread and developed, and the number of supporters of the “insulated Swedish stove” will constantly grow. For energy saving technologies There is certainly a bright future in construction.
Video: an example of the construction of an “insulated Swedish stove” with explanations from the master
USHP is a modern and thermally efficient foundation. And not just the foundation, not just a concrete slab. This is the real foundation of your home. It includes a ready-made system for comfortable heating with underfloor heating throughout the entire area, distribution of water supply pipes, sewerage and electrical cables, high-quality floor insulation, and its smooth surface is suitable for laying finished flooring.
The Swedish slab is suitable for frame houses, houses made of aerated concrete, timber, logs, for SIP and other houses and can be built on almost any soil.
In this picture, the designer and I tried to depict the USP in cross-section. So, let's break it down:
1. Cushion 2. PSB/EPS - permanent formwork 3. Insulated blind area 4. Drainage 5. Storm drain 6. Reinforcement 7. Heated floor pipes 8. Concrete slab 9. Pipes and cables
1. Cushion under the stove
Before pouring concrete, we need to do a lot of other things, and we start by preparing the cushion - the base on which the formwork will be placed and on which our slab will stand. It is necessary to prepare a flat sandy area and compact it properly using a special machine - a vibrating plate.
My companion, Grigory, made a short series about the construction of the USP. The first episode is dedicated to preparing the pillow, this is what it looks like in the video:
The “pie” of the pillow depends on the type of soil, ranging from simple removal of the fertile layer, backfilling with sand and compaction, to complete replacement of the soil under the slab to a greater depth and compaction with a heavy vibratory roller. The preparation of the cushion is extremely important; based on the result, you must check the quality of the compaction with a penetrometer.
2. We install formwork from PSB\EPS
Next, on the prepared site, permanent polystyrene foam formwork is leveled. This is not at all the fragile foam plastic that you are used to seeing in a TV box, PSB 25/50 (PPS 14/35 according to the new GOST) or, moreover, EPS is much denser and more durable. It turns out that between the ground and concrete there will be a thick layer of excellent, dense insulation. This will allow us to heat your home rather than warm the ground underneath it.
In addition, the foam plastic will not allow the soil under the house to freeze, therefore, there will be no frost heaving, there will be no dangerous movements of the foundation, cracks in the walls and other troubles.
At this stage, sewer pipes are also laid, water and electrical cables are introduced, and grounding is made (number 9 in the picture). Most often, along with the foundation, I immediately install a septic tank or VOC, so the sewerage issue is resolved at this stage.
It’s also worth adding that I usually line the outer part of the formwork (the so-called L-block) with flat slate. During the construction stage, it reliably protects the PSB from damage, and can also be used in the future - you can simply paint it in the desired color or cover it with mosaic plaster and the finishing of the base is ready. It is also convenient to attach plinth panels to flat slate.
This is what the finished base looks like:
By the way, regarding the height of the USP base (height from the ground to the edge of the slab). It turns out to be small - about 20 centimeters, but this is rather a plus - there is no need to make a porch with steps at the entrance to the house. However, at the request of the customer, the height can easily be increased. Firstly, an extra 10 centimeters can be added by additionally filling the pillow, and secondly, the same amount can be added by using an additional layer of insulation under the slab.
3,4,5. We make storm drainage, drainage, blind area
When it rains, streams of water run from the roof through the drainpipes and this water needs to go somewhere. For this purpose, storm drains and storm inlets are made, these are something like hatches under drainpipes where all the rainwater flows. And she goes into a ditch or a well. Believe me, this is much better than puddles around the house.
In most areas, due to dampness, drainage is also needed, you can read about it in detail on the Internet, but in a nutshell - this is needed to drain water away from the house, so that it is dry. And this is also done immediately, along with all other earthworks.
Around the foundation, along the perimeter, sheets of expanded polystyrene are buried, covered with a thick film - this is an insulated blind area. It is needed to prevent freezing and frost heaving of the soil around the foundation. You can fill it with sand and, subsequently, decorative stone, or you can immediately beautifully concrete it.
So, it turns out that we have removed all excess moisture from under and around the house, and also insulated the foundation and its perimeter. This means that there is no opportunity for frost heaving of the soil - dry sand, protected from frost by foam plastic, will no longer move.
6. Reinforcement
You can’t just take, mix cement and pour it into the finished formwork. Metal reinforcement gives strength to concrete structures. In the classic USHP, the entire area is covered with welded reinforcing mesh, and reinforcement bars are used in the stiffeners. For a heavy house, additional ribs and reinforcement cages can be made, double reinforcement can be used, etc. All this is designed based on the planned load on the foundation, i.e. depends on the material from which the house will be made and its size.
7. Warm floors throughout the house at once
Underfloor heating pipes are laid throughout the entire area of the house. The house is divided into several zones, for example, kitchen, living room, bedroom, bathroom. Each zone has its own underfloor heating circuit, which can then be adjusted using a manifold.
It turns out that the whole house is heated with underfloor heating. And if the house is well insulated, then such a system is sufficient for heating in any frost (for a 1-story house or for the first floor of a 2-story house). And this is a very comfortable warmth, it comes evenly from the entire surface of the floor in all rooms, which is much more pleasant than a classic radiator under the window.
Since the warm floor is poured into concrete, the concrete monolithic slab serves as an excellent heat accumulator. It does not warm up immediately, but when it gains heat, it takes a very long time to release it. Even if your gas or electricity is turned off, you won’t feel it right away, maybe after a day or more. The temperature in the house will drop very slowly!
The Comisa underfloor heating manifold regulates the flow of coolant along the contours
* in fact, the order of the story is a little broken, most often the TP pipes are mounted before the reinforcement and attached directly to the foam - this is the best option, but for understanding the meaning of the USP this does not play a role.
9. Communications - water, electricity, sewerage
Here we will skip a little and move on to point 9. In addition to the heated floor, all necessary communications are laid inside the slab - this electrical cables(they can be routed to any place, for example into future walls), pipes for cold/hot water, sewer pipes, water drains for a future shower, any other cables/air ducts can be routed to your taste.
Standard set: heated floors, sewerage, cold water/hot water supply and electrical cables
The USHP slab is not created for an abstract house, say, 10*10 in size. You need at least a preliminary design, then you can immediately install heating in the rooms, run pipes to future bathrooms and the kitchen, install underfloor heating and water supply manifolds in the technical room, etc.
Outputs of hot and cold water pipes, there will be a collector here
This is what the “filling” of a standard slab looks like (the first part of the video):
8. Monolithic concrete slab = subfloor
Work on the USP is completed by pouring concrete and grouting/grinding it. When all communications and heated floors are ready, all leads and cables are checked, the integrity of all pipes is pressure tested, a mixer arrives and pours a high-quality concrete mixture. No homemade concrete, only a mixture from a proven concrete plant, with all the documents and samples.
After pouring, smooth the concrete with a large trowel.
Some time after pouring, when the concrete gains a little strength, the surface is polished with a special trowel, which is also called a “helicopter”. Both during pouring and grouting, the evenness of the slab is constantly monitored by a laser level.
This is how a helicopter works:
As a result, we get a smooth concrete base with minimal differences. You can immediately lay tiles or laminate on it, there is no need to fill in additional screed - everything is already ready.
Let's summarize the benefits
By ordering USHP, after completion of the work you will immediately receive:
- Foundation - monolithic concrete slab;
- Divided communications - water, sewerage, electricity, grounding, etc.;
- Ready-made heating system - warm floors throughout the entire area of the house;
- Floor insulation - under the slab there is a thick layer of PSB/EPS;
- Insulated blind area - no freezing of the soil around the house;
- The finished subfloor is smooth and you can immediately lay tiles or laminate on it;
- Finishing the base with flat slate - you can simply paint it;
- Storm drainage and storm water inlets [optional];
- Drainage [optional];
- The resolved sewerage issue is a septic tank or VOC [optional].
Now let's compare
If you compare USHP with screw piles or with a regular concrete slab or with MZLF... The comparison will not be entirely in favor of these types of foundation. That is, piles, of course, will cost less. And you can build exactly the same good house on them. BUT how much work will need to be done later? Who will make them? How much will it cost?
Assessing and comparing costs different types foundation, please consider all of the above. USHP is a ready-made zero cycle, a turnkey foundation. Although I don't like this definition, it really is true.
On USHP you just need to put a box at home, and everything else is already inside - heating, communications, insulation. And on the same screw piles you need to make a lower ceiling, insulate it, install communications, do their wiring around the house, fill in the screed, install heating, do something clever with the finishing of the high base... In general, it’s up to you.
You can view detailed reports on the foundations I recently built in the section.
Foundation construction technologies vary and are used depending on many conditions - the nuances of the soil, climate, and the characteristics of the object. A monolithic slab is considered the most durable and reliable. However, it often becomes unacceptable due to the cost - up to 50% of the total budget allocated for construction, taking into account the combination of the price of concrete and the use of equipment. There is a way out - to install a slab under the future house
USHP is a new word in foundation construction. Let's look at it in detail.
USP technology foundation
Like any other foundation, USHP (insulated Swedish plate) is a “pie” of numerous building materials. These include:
- Concrete pouring.
- Reinforcement.
- Shock-absorbing layers.
- Hydro- and thermal insulation.
That's it in a nutshell. In addition, utility lines and heated floors run deep into the foundation.
Now more details.
Monolith
Unlike the classical one, the USHP technology provides a small but sufficient layer of concrete for the rigidity of the entire structure - from 10 cm. Due to the small thickness, pouring occurs in one day, which has a positive effect on the quality of the foundation - there is no layering, and on the cost - no need to use mixer several times.
Reinforcement
The amount of steel rod is also reduced, but this does not affect the strength of the foundation - the two planes of the mesh are connected to each other, preventing damage to the foundation during compression and bending. Concrete cracking is excluded, unlike classical technology.
Cushioning layers
Crushed stone and sand traditionally serve in this capacity, but in a classic slab they are layered on top of each other. In USHP the order of installation is different. In addition to sand and crushed stone, there is clay - the main “lock” for moisture and geotextiles laid between mineral layers. Additional waterproofing serves as an obstacle to groundwater - if the sand is not covered, it will come close to the insulation, which is unacceptable.
Insulating layers
For reliable operation of the foundation, it is necessary to protect it not only from moisture, but also to insulate it. Temperature changes can create condensation, cause heaving and cracking. The insulation, as a rule, is styrene derivatives - it reliably copes with the assigned tasks, extending the shelf life of the platform by 1.5–2 times in comparison with a classic monolith.
USP problems
It is quite clear that a house built on a USHP foundation will become ergonomically advantageous - less resources are required to heat the building, and accordingly, bills for heat or electricity consumption will no longer be exorbitant. Nevertheless, there are disadvantages, considering which it is worth thinking about the advisability of using this type of foundation. So:
- The foundation is applicable for the construction of “light” houses - half-timbered, frame, OSB boards. As a last resort, it is allowed to use blocks or brickwork. You should also take a responsible approach to the choice of roofing material.
- USP is used in relatively cold regions of the country. For mild or average climates it is not advisable to use it due to too high heat capacity. It can be harmful, as it threatens discomfort, mold formation, and loss of structure rigidity.
- The foundation is suitable for high groundwater levels and capricious soil - heaving, floaters. This is also typical for a classic stove. Otherwise, it is poured if the number of floors of the house is large or the material for construction is heavy.
- It is not recommended to install USP on difficult terrain. The soil has the property of movement, so for the structure this is fraught with a violation of the integrity due to the small layer of concrete pouring.
- Having carefully analyzed the site and the architectural plans of the facility, or done this with the help of specialists, they come to the conclusion about using or not using the Swedish insulated slab as the foundation for their own home.
USP device technology - step by step
One of the advantages of the Swedish insulated board is the speed of installation and the ability to do everything yourself. The algorithm is as follows:
Site marking
To do this, you should project the contours on the ground in advance, in accordance with the plans of utility lines - they will pass through the thickness of the slab.
In addition, take into account the importance of the gasket storm sewer– water must not be allowed to approach the contours of the foundation. For work, stakes and a cord are used - the latter, for convenience, is painted in a contrasting color to accurately see the boundaries.
Digging and arrangement of the pit
Unlike a classic slab, the depth of the pit for installing a USP is small - 45–50 cm is enough. The owner has the right to hire equipment for removing soil, but the depth is quite suitable for manual processing.
An important condition is that the entire fertile layer should be removed, since the thickness of the soil with roots will attract moisture and create conditions for dampness and mold growth.
The perimeter of the USHP pit is larger than the boundary of the walls by at least 1 m. This value will include trenches for laying corrugated pipes for water drainage. Accordingly, they make a slight slope in one direction to ensure gravity flow. After sampling the soil, it is recommended to compact the leveled area with clay. To do this, dry and crushed material is sprinkled inside in an even layer and, after moistening, compacted.
Laying drainage pipes
The next step will be laying drainage pipes. To do this, the finished area of the pit is covered with geotextiles with the obligatory installation of the material on the walls of the pit and the ground plane above the trench. Before laying, the entire finished surface is covered with fine crushed stone, paying attention to the trenches for drainage - there the screening layer is compacted.
The pipes are laid and a layer of crushed stone is laid again. After which the surface is covered with geotextile - great importance is attached to the protection of the USP.
Installation of home communication networks
The project must clearly show how communications - water supply, sewerage and other networks - will pass through the foundation. This is important, since the technology of the platform does not provide for its repair and, therefore, all wiring is arranged in advance.
There is a difficulty - it is necessary to duplicate the circuits in case of blockage. Then during operation it will be enough to turn on the “bypass” while the main circuit is being repaired. The laid communications are covered with sand, which must be compacted manually - with a vibrating plate, for example.
Thermal insulation
It's time to warm up. For this, different materials are used - penoplex, technoplex, styrex and others. They are foamed slabs of extruded polystyrene, which have excellent heat capacity characteristics. The work goes quickly, since the weight of one slab is insignificant.
The styrenes are laid in two layers. Each is laid using plywood floor technology, when the joints of the first layer fall on the plane of the second. Also, you cannot combine the joints of one row with a similar installation of the adjacent one. That is, the work is carried out in a staggered manner.
The fastening is done with special plastic nails with wide heads. We must not forget about laying styrene sheets on part of the blind area and plinth - small protrusions of the sheets will help to “adhere” the material.
Reinforcement and installation of heated floors
Regardless of the desire to make or not make warm floors, the reinforcement is done in two layers. The first is a grid on which the system's collectors will be laid in the future. Still, USP technology is more productive in tandem with heated floors, so after distributing the wiring, the system is pressurized and checked.
Afterwards the second layer of armored belt is laid.
It is important - you cannot weld the rods together - only knit them.
High temperatures are detrimental to the composition of steel and consequences in the form of loss of rigidity are guaranteed.
Formwork for USP
The formwork is classic, using plywood panels and supports to hold the mass. The walls from the inside are lined with the same polystyrene; subsequently, when removed, a surface identical to the plane of the foundation is formed, ready for further processing.
To construct the formwork, you don’t have to purchase special plywood; flat boards are fine. They are used in subsequent construction, since they are free of concrete.
Pouring concrete
The final stage of construction of the Swedish insulated slab - pouring concrete - is carried out in one go. It is allowed to use the mass in portions with an interval of 1 hour, no more.
Automatic tamping with a vibrating plate must be used. Since a perfectly flat surface is rarely achieved, the finished slab is ground. Otherwise, you will have to lay a leveling screed. After three days, the wooden panels are removed.
Caring for the stove until it is ready is standard. Watering during hot periods and covering with PVC film.
Simple but precise execution in accordance with the described steps guarantees a high-quality platform for a country house.
Progress does not stand still. Manufacturers working in the construction industry are offering all new materials and technologies to speed up, as well as improve technical performance and reduce construction costs. One of the latest developments in foundation technology came from Sweden. New way foundation device has significant advantages and is confidently used for private and cottage construction. USHP foundation – technology for fast and economical foundation construction.
What is USP
USP (insulated Swedish slab) is a slab, monolithic shallow foundation. It has insulation around the perimeter and over the entire area of the sole. The base slab according to the USHP system is the finished subfloor of the first floor. In addition, now, in addition to communications, a heated floor system is now being built into the foundation.
Used as insulation extruded polystyrene foam, which is specifically designed for insulating the foundation from below. Graphite particles are added to its composition, which increases the material’s compressive strength and resistance to impact. sunlight. Also, extruded polystyrene foam for USHP is practically does not shrink, and thanks to the complete insulation of the foundation base, it eliminates the problems of soil heaving.
Advantages and Disadvantages
Advantages of using USHP foundation:
Considering the large number of advantages of using a Swedish stove, there are still some disadvantages that limit the use of USP technology.
- The Swedish stove is only suitable on a reliable basis. It is unacceptable to install the slab on vegetative, silty or peaty soils.
- Most of the communications are located directly in the foundation. If necessary, access to them is almost impossible.
- USHP cannot be used for the construction of multi-story and heavy buildings. This technology is used only for one-story or small two-story buildings.
- When constructing such a foundation, the possibility of constructing a house with a basement is excluded.
Required tools and materials
Setting up an insulated Swedish stove with your own hands is not as difficult as it might seem at first glance. Before starting work, a design of the building under construction must be prepared and the construction site must be determined. A small team with experience will quickly and efficiently install the USP. However, by following production technology, as well as using high-quality materials, you can construct a foundation slab using Swedish technology with your own hands.
Construction materials for USHP installation:
Required tool:
Step-by-step scheme of work execution
- Earthworks. If construction is carried out on an area with unreliable silty, soil-vegetative or peaty soils, they must be removed and replaced with medium-sized sand.
The foundation is arranged with a horizontal base. Its depth should take into account the thickness of the foundation with insulation and the sand cushion, which should be at least 40 cm thick.
The bottom of the foundation is filled with sand and distributed evenly over the entire area using a vibrating plate. Tamping is carried out layer by layer, in several stages.
- Drainage system. A trench is laid around the perimeter of the pit into which a flexible drainage pipe is laid. Before laying the pipes, the bottom and walls of the trench are covered with geotextiles.
- Laying geotextiles. Geotextiles are spread over the entire area of the pit with an overlap of at least 15 cm. Such material strengthens the soil and provides drainage.
- Backfill. Backfilling with sand is carried out in several layers to the required level according to the project. Each layer should be no more than 15 cm and is compacted with a vibrating plate. When compacting, it is necessary to water the sand.
- Engineering communications. Utilities and sewerage are laid in the sandy base. Laying is carried out according to the project. For temporary fixation of communications, fittings and clamps are used. The ends of communications and sewer pipes are brought to the surface.
- Wooden frame. A frame made of edged boards is arranged around the perimeter. Stands are installed, to which it is attached with screws using a screwdriver. edged board. For strength, the frame is reinforced with braces.
- Backfilling with crushed stone. For these purposes, material of the middle fraction is used. Backfilling in progress over the entire foundation area to a given point. The layer of crushed stone should not be less than 10 cm. After backfilling, compaction is performed using a vibrating plate.
- Thermal insulation device. For thermal insulation, extruded polystyrene foam boards are used, which are specially designed for foundation insulation. Such plates, due to the addition of graphite, have increased compressive strength. The thickness of thermal insulation boards must be at least 100 mm. Insulation is carried out not only horizontally, under the foundation slab, but also vertically.
If necessary, the wooden frame can be extended and strengthened so that it can withstand the pressure from concrete during pouring. The insulation is cut to size and installed vertically, pressing it against the sides of the wooden frame. This design is both a vertical insulation of the end part of the slab and a formwork for pouring a concrete slab.
Horizontal thermal insulation is performed over the entire area of the foundation slab. The insulation is laid on crushed stone in one layer and pressed tightly against each other. Then, zones under the load-bearing walls are marked on the surface of the insulation. In these areas, insulation is not installed as a second layer. Subsequently, reinforced concrete stiffeners will be installed there. With the exception of the support zones of load-bearing structures, the next layer of thermal insulation is laid over the entire area of the foundation.
To prevent thermal insulation boards from moving, they should be fix using long screws. At the outlets of sewer pipes and communications, you can easily make holes in the insulating boards using a stationery knife.
- Swedish plate reinforcement. Reinforcement of the USP consists of two stages: reinforcement of the grillage with a frame and the plane of the foundation slab with reinforcing mesh.
Reinforcement of stiffeners (grillage) performed by reinforcement cage. It is made of four rods with a diameter of 12 mm, which are connected by structural clamps made of reinforcement 8 mm thick. The clamps are located in 300 mm increments. The frame is assembled using the knitting method, the rods and clamps are connected with knitting wire. To avoid damage to the insulation, the spatial frame is assembled separately, and then, ready-made, it is placed on clamps in the grillage area. There the frames are connected to each other.
Reinforcing mesh is laid over the entire area of the foundation. Her knitting is performed directly at the installation site. The mesh is made of rods with a diameter of 10 mm with a cell size of 150 x 150 mm. The mesh is placed on special PVC clamps.
- Installation of a heated floor system. USHP foundation technology involves installing a heated floor directly into the foundation slab. This will ensure heating of the first floor without additional heating.
- Heated floor pipes according to the project stacked on reinforcing mesh
and are attached to it with nylon clamps. In places where load-bearing walls will be supported or doorways will be constructed, the pipes are protected with sleeves made of corrugated protection or HDPE pipes.
The collector is installed strictly together, as indicated by the project drawings, and at the required height. To install the collector, four one and a half meter reinforcing bars are driven into the foundation pad. A board is attached to them and the collector is temporarily fixed at the elevation specified by the project. Flexible underfloor heating pipes are connected to the collector. In places where pipes rise to the collector, it is necessary to protect them using special corrugated protection.
After installing a heated floor and before pouring concrete, it is necessary check the quality of heating installation. To do this, the underfloor heating pipes are filled with coolant, and pressing is performed, which will show where the system's tightness has been compromised.
- Concreting. You can order delivery of concrete only after all preliminary work has been completed and everything is ready for concreting. The grade of concrete is determined by the construction project. The most convenient way to fill using a concrete mixer truck with an installed concrete pump. The solution is distributed over the entire area using shovels and trowels. It is necessary that the concrete fills all hard-to-reach places. An internal vibrator is used to compact the concrete mixture.
The time between delivery of concrete and its placement should not exceed one hour. If there is a need to interrupt the concreting process, you can suspend the work for a while, having previously organized working seams. Before resuming concreting, the working joints must be moistened with water and treated with a cement laitance primer.
