Insulated monolithic foundation slab. Insulation of the foundation slab - materials and options for heat saving. What materials can be used to insulate the slab foundation

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

Insulation of the foundation of a monolithic type with polystyrene foam

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

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

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

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

Expanded polystyrene practically does not pass water and is not afraid of exposure to chemically aggressive environments. Thermal insulation with this material is made in regions with severe winters and very cold weather. Expanded polystyrene perfectly copes with repeated cycles of freezing and defrosting, while its performance does not change at all. Expanded polystyrene is usually sold in the form of plates.

Back to index

Why polystyrene and not another material?

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

A few tips:

• work starts from any corner of the foundation;
• slabs must be laid from the bottom up with a shift in the rows, that is, something similar to brickwork should be obtained;
• at a height approximately equal to the width of the plate, pull the rope. The horizontal tension is checked using the building level;
• the first row of the heat-insulating layer is laid. This is done so that subsequent rows of plates do not diverge, otherwise all the insulation will simply become useless.

Back to index

How to properly mount polystyrene foam boards on the walls?

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

When conducting work, it is necessary to carefully monitor the connection of adjacent plates. It should be clear, without cracks and be in the castle.

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

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

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

This is necessary to prevent damage to the waterproofing.

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

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

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

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

Insulation of the slab of any foundation is one of the most important things in the construction of a house. It is best to do this in the warm season, and you can not do this in rainy weather. Insulation of a monolithic foundation slab is especially important for cold regions, where the soil freezes at great depths. Heaving soils during freezing can increase in volume, which leads to deformations of the entire building. Therefore, it is so important to take care of the external insulation of the foundation. This will help reduce the heat loss of the entire future building and preserve its durability.

What does foundation insulation provide?

The better all the work is done, the longer and more reliably the building will stand idle. And most importantly - the house will remain warm even in severe frosts. Do not forget that most of the cold penetrates the house through the foundation. And if the building has a basement (billiard room, gym), then you should take care of the internal insulation. This is especially important if the basement is not heated. But the most important is the external insulation of any residential building.

The main reasons why insulation is necessary:

1. Improvement of waterproofing properties.
2. Reduced heat loss.
3. Reducing home heating costs.
4. Prevention of condensation on the walls.
5. Stabilization of the internal temperature of the building.

All this will help not only to always feel comfortable in your home, but also increase its lifespan.

What kind of insulation to use for the foundation?

The most important part of the job when insulating a fresh foundation slab is required is the selection of the right material. It should not deform under the pressure of the soil and absorb moisture. These are the most important parameters of any thermal insulation. Soft materials such as mineral wool will not work. The best option is polyurethane foam and extruded polystyrene foam. Both of them have excellent thermal insulation characteristics and a fairly low cost, which is also important in construction.

polyurethane foam

This material is universal, as it combines not only thermal insulation, but also sound and waterproofing properties. To use this type of insulation, you will need special equipment, as it must be sprayed. For full insulation, 50 mm of insulation thickness, laid in several layers, is sufficient. All joints after insulation must be sealed.

This material has a number of positive properties:

• low thermal conductivity;
• good adhesive properties;
• reliability;
• durability.

And most importantly, when using polyurethane foam, there is no need to use additional funds for steam, water and waterproofing. It has only one drawback - the need to use special equipment. Therefore, for this method of insulation, either considerable capital investments or the help of experienced specialists with the appropriate equipment will be required.

Extruded polystyrene foam

This type of insulation is significantly lower than polyurethane foam, it is easier to install. Such material consists of plates that do not pass and do not absorb moisture. It retains its thermal insulation properties for a long time even in cold regions. Advantages of extruded polystyrene foam:

• high strength;
• long service life;
• reliable thermal insulation properties.

It is most often used if necessary to insulate the foundation, since it can be mounted independently, without the use of additional equipment.

Extruded Styrofoam with Grooves

This is a new kind of insulation. Milling grooves on the surface of expanded polystyrene boards are great for insulating the foundation. It is used together with a geotextile cloth as fastening drainage. Its main properties:

• good thermal insulation;
• protective layer of waterproofing;
• waterproof.

Insulation of the foundation with polystyrene foam

To insulate a monolithic slab, you can use both polystyrene foam and polyurethane foam. But the first option is preferable. Expanded polystyrene is the most efficient and least expensive, and most importantly, it is easy to install. Before proceeding with its installation, it is recommended to lay waterproofing, then you can start laying extruded polystyrene foam boards.

The most effective method of insulating the foundation with this material is to use it in areas of soil freezing. The insulation is mounted to the freezing depth. This is quite enough. When insulating, special attention should be paid to the corners: in such places, the used polystyrene foam should be thicker than in other areas. Along the perimeter of the building, it is imperative to perform soil insulation. To do this, under the design of the blind area, it is necessary to place a heater.

All rows of extruded polystyrene boards must be laid end to end, from bottom to top. Large seams are filled with mounting foam. This will provide high tightness, heat-insulating and waterproofing properties. The plates are planted on polymer glue or mastic, and then pressed with a layer of soil. When insulating, it is important to take into account that all the plates are of the same width; already used material cannot be used, this can violate the tightness. This method is suitable for all types of foundations, including monolithic ones.

Insulation of the foundation with polyurethane foam

When insulating a monolithic foundation using polyurethane foam, it is important that there are no gaps and gaps. The insulation must form a completely closed loop. This will achieve maximum thermal insulation properties. Its spraying on the foundation is carried out using special equipment. The material then hardens within 20 seconds. In general, the whole process of installing insulation is quite simple and fast. The application of polyurethane foam is done in several layers, after each of them dries. One layer should be approximately 15 mm thick.

Upon completion of all work, it is produced by soil. Equipment for the installation of such insulation can be purchased at specialized stores or rented. But it is easier and faster to use the services of professionals.

Insulation of a monolithic slab updated: February 26, 2018 by: zoomfund

The key to the longevity of any structure is a reliable foundation on which it is based. The “zero cycle”, that is, the construction of the foundation, is one of the most important stages of construction. Mistakes and shortcomings made during such work, neglect of technological recommendations or unjustified simplification of certain operations can lead to very unpleasant, and sometimes even catastrophic consequences.

One of the most common types of foundations is tape. It is quite versatile, suitable for most residential or commercial buildings, it is highly reliable, stable even on “difficult” soils. But he will show all these qualities only if the concrete tape is reliably protected from negative external influences. Unfortunately, not all novice builders know that the foundation of the house is in particular need of hydro and thermal insulation. One of the solutions to this problems - insulation foundation with polystyrene foam, the technology of which is quite accessible to everyone.

Why is the foundation insulated?

At first glance, it even looks paradoxical - to insulate a monolithic concrete belt, buried in the ground and somewhat rising above the ground in the basement. What's the point if there's no living quarters here? What difference does it make whether the “foundation is warm” or whether it remains open?

Unfortunately, such an amateurish view is not at all uncommon, and many site owners, for the first time in their lives, starting to independently build their own home, ignore the issues of thermal insulation of the foundation and do not even provide for the corresponding costs for these activities. Alas, in this way they are laying a "delayed-action mine" under their dwelling.

• The strip foundation is usually buried in the ground below the freezing level of the soil. It turns out that the temperature of the sole or the lower part of the tape throughout the year is approximately the same, but the upper part of the foundation, depending on the season, undergoes either heating or cooling. This unevenness in a single concrete structure creates the strongest internal stresses due to the difference in linear expansion of different sections. These internal loads lead to a decrease in the strength properties of concrete, to its aging, deformation, and the appearance of cracks. The way out is to ensure the approximate equality of the temperature of the entire tape, for which thermal insulation is necessary.

• An uninsulated foundation becomes the most powerful bridge for the penetration of cold from the outside to the walls and floors of the first floor. Even seemingly reliable thermal insulation of floors and facades will not solve the problem - heat loss will be very large. And this, in turn, is not only an uncomfortable microclimate in the residential area, but also absolutely unnecessary expenses for payment of energy carriers for heating. Conducted heat engineering calculations prove that competent insulation of the foundation provides up to 25 - 30% savings.
• Of course, high-quality concrete mortars have their own operational "reserve" in terms of frost resistance - this is the calculated number of cycles of deep freezing and thawing without loss of strength properties. But you still need to spend this “reserve” wisely, and it is better to protect the foundation to the maximum extent from the influence of negative temperatures.
• The insulated foundation walls will dampen less, as the thermal insulation layer will bring the “dew point” out. It - more one plus insulation tape.
• In addition to insulating the outer walls, conscientious builders also install a horizontal layer of thermal insulation, which will prevent the penetration of cold through the soil to the base of the foundation. This measure is aimed at reducing the likelihood of soil freezing near the belt, which is dangerous for swelling, the appearance of strong internal stresses in the reinforced concrete structure and its deformation.
• And, finally, the thermal insulation mounted on the walls of the foundation also becomes a good additional protection against soil moisture, and in addition, it becomes a barrier that protects the mandatory layer of waterproofing from mechanical damage.

To solve the problem of warming the foundation, a thermal insulation stand is placed on its outer wall - from the base (sole) to the upper edge of the base. No need to rely on the insulation of the foundation from the inside - this will not eliminate external influences in any way, and can only slightly improve the microclimate in the basement.

Start with waterproofing!

Before moving on to the technology of foundation insulation, one cannot help but touch on the issues of its high-quality waterproofing - without this, all the work can be done in vain. Water, in "alliance" with temperature changes, turns into a serious threat to the foundation of the house:

First of all, everyone knows the property of water to expand upon transition to a solid state of aggregation - upon freezing. The penetration of moisture into the pores of concrete at low temperatures can lead to a violation of the integrity of the structure, rupture, cracking, etc. This is especially dangerous in the basement and at a shallow depth of the tape.

• No need to think that soil moisture is pure water. A huge amount of organic and inorganic compounds is dissolved in it, which enters the soil with vehicle exhausts, industrial emissions, agricultural chemicals, spills of oil products or other liquids, etc. Many of these substances are extremely aggressive towards concrete, causing its chemical decomposition, erosion, crumbling and other destructive processes.
• Water itself is a strong oxidizing agent, plus it contains a lot of the mentioned compounds. The penetration of moisture into the thickness of the concrete will necessarily lead to the oxidation of the reinforcing structure - and this is fraught with both a decrease in the design strength and the formation of cavities inside the tape, which then turn into cracking and peeling of the outer layers.

• And in addition to all that has been said - water also causes a gradual washing out of the concrete surface - cavities, shells and other flaws are formed.

It is not necessary to rely on the fact that at the construction site the groundwater is located very deep, and does not pose a particular threat to the foundation. The danger lies much closer:

• Water falling with atmospheric precipitation or falling on the ground in other ways (spill, melting snow, pipeline failures, etc.) forms the so-called filtration layer, by the way, the most dangerous in terms of aggressive chemical terms. It happens that in the thickness of the soil at a shallow depth there is a waterproof clay layer, which leads to the creation of even a fairly stable surface water horizon - perched water.

The moisture concentration in the filtration layer is a variable value, depending on the time of year and settled weather. The most important role in reducing the negative impact of this layer on the foundation will be played by the organization of proper storm sewers.

• The second level is a fairly constant concentration of capillary moisture in the soil. This is a fairly stable value., which depends on the time of year and the weather. Such moisture does not have a washing out effect, but its capillary penetration into concrete is quite possible if the foundation is not waterproofed.

If the site is characterized by high humidity, for example, is located in a swampy area, then waterproofing is not limited - need to protect the foundation is also the creation of a drainage system.

• Underground aquifers are very dangerous for the foundation. True, they are also quite stable in their location, but in terms of occupancy they depend on the time of year and the amount of precipitation.

If at the construction site there is a tendency to close occurrence of such layers, then very high-quality waterproofing and a drainage sewerage system will be required - here the effect of water may not be limited to simply penetrating concrete, but also cause serious hydrodynamic loads.

An approximate scheme for waterproofing the foundation is shown in the figure:

1 - sand and gravel pad on which the foundation strip (2) is based. This pillow also plays a role in the overall waterproofing scheme, performing the functions of a kind of drainage.

The diagram shows a block strip foundation, therefore, a layer of horizontal waterproofing (3) is provided between the sole tape and the laying of blocks (4), which excludes capillary penetration of moisture from below. If the foundation is monolithic, then this layer does not exist.

5 - coating waterproofing, on which roll pasting (6) is laid on top. Most often, in private residential construction, tar mastic and modern types of roofing material on a polyester fabric base are used in pairs.

7 - a layer of thermal insulation of the foundation, which in the upper basement is additionally covered with a decorative layer - plaster or facing panels (8).

From the foundation begins the construction of the walls (9) of the building. Pay attention to the obligatory horizontal "cut-off" layer of waterproofing between the foundation and the wall.

To perform waterproofing work, the foundation tape is exposed to the very sole - this will also be required for its further insulation.

Within the framework of this article, it is impossible to talk about all the nuances of waterproofing work - this is a topic for a separate consideration. But still, it would be advisable to give recommendations on the optimal use of waterproofing materials - they are summarized in the table:

The table shows 4 classes of buildings:

1 - technical buildings, without electrical networks, with a wall thickness of 150 mm or more. Damp spots and even small leaks are acceptable here.

2 - also technical or auxiliary buildings, but already with a ventilation system. Wall thickness - not less than 200 mm. Moisture spots are no longer acceptable, only slight damp evaporation is possible.

3 - this is the same class that is of interest to private developers - it includes residential buildings, social buildings, etc. The penetration of moisture is no longer allowed in any form. Wall thickness - at least 250 mm. Natural or forced ventilation is required.

4 - objects with a special microclimate, where a strictly controlled level of humidity is required. In a private building, you will not have to meet this.

It should not be concluded from the table that one of the indicated layers is sufficient. Optimal for the foundation, we repeat, will be a combination of coating and gluing waterproofing - this will create a reliable barrier against moisture penetration.

After the foundation has received reliable waterproofing, you can proceed to its insulation.

Expanded polystyrene as insulation for the foundation

Of all the variety of thermal insulation materials, it is polystyrene foam that is the best choice for use precisely in conditions of foundation work - with inevitable contact with moisture, with load soil, etc. . There are other technologies, but if we consider in the context of independent work, without the involvement of craftsmen and special equipment, then, in fact, there is no reasonable alternative.

One of the best representatives of the class of extruded polystyrene foam - "Penoplex"

It should be noted right away that this will not be about expanded polystyrene, which is often called polystyrene foam (it is of little use for such use), but about extrusion types of polystyrene foam. Most often, for the insulation of the foundation, they choose "penoplex" - plates of a certain size and configuration, which are very convenient to work with.

Penoplex prices

penoplex

The advantages of "penoplex" are as follows:

• The density of this material lies in the range from 30 to 45 kg/m³. It is not difficult during installation, but this does not at all mean the low strength of such expanded polystyrene. So, the force for deformation by only 10% reaches from 20 to 50 t/m². Such a heater will not only easily cope with the pressure of the soil on the walls of the foundation tape - it is even laid under the seam or used as an insulating base when pouring a monolithic slab foundation.
• The material has a closed cell structure, which becomes a very good additional waterproofing barrier. Water absorption "Penoplex" does not exceed 0.5% during the first month, and does not change in the future, regardless of the duration of operation.
• Extruded polystyrene foam has one of the lowest thermal conductivity values ​​- a coefficient value of about 0.03 W / m² × ° С.
• "Penoplex" does not lose its outstanding performance characteristics in a very wide temperature range - from - 50 to + 75 ° C .
• The material is not subject to decomposition (except for exposure to organic solvents, which is very unlikely in soil). It does not emit substances harmful to humans or the environment. Its service life in such conditions can be 30 years or more.

Penoplex can be of several modifications designed to insulate certain elements of the building. For example, fire retardant additives are included in some types of additives that increase the fire resistance of the material. This is not required for foundation work. For insulation, "penoplex" of the brand "35C" or "45C" is usually purchased. The numbers in the marking indicate the density of the material.

Release form - panels, most often orange. The size of such plates, 1200 × 600 mm, makes them very convenient for installation. The thickness of the panels is from 20 to 60 mm in increments of 10 mm, as well as 80 or 100 mm.

Plates of this "foam" are equipped with a locking part - lamellas. This is very convenient when laying a single insulating surface - the lamellas, overlapping one another, block the cold bridges at the joints.

Penoplex is the best solution for foundation insulation!

This insulation is produced in several modifications, each of which is designed for thermal insulation of certain elements of the building. Including in this line is presented and "Penoplex-Foundation".

More about - in a special publication of our portal.

How to correctly calculate the insulation of the foundation polystyrene foam

In order for the insulation of the foundation to be of really high quality, it must first be calculated - for a specific building and for the region in which it is being built.

It has already been said that a complete thermal insulation of the foundation should consist of at least two sections - vertical and horizontal.

The vertical section is expanded polystyrene plates fixed directly to the outer walls of the foundation tape - from the sole to the upper end of the basement.

The horizontal section should form a continuous belt around the perimeter of the building. It can be located in different ways - at the level of the sole with shallow tapes, or at another level above the freezing point of the soil. Most often, it is located just below ground level - it becomes a kind of basis for pouring a concrete blind area.

The diagram shows:

- Green dotted line - ground level;

- Blue dotted line - the level of soil freezing, characteristic of a particular area;

1 - sand and gravel cushion under the foundation tape. Its thickness (hп) is about 200 mm;

2 - foundation tape. Depth (hз) can be from 1000 to 15000 mm;

3 - sand filling in the basement of the building. It will subsequently become the basis for laying the insulated floor;

4 - a layer of vertical waterproofing of the foundation;

5 - laid layer of thermal insulation - foam boards;

6 - horizontal section of foundation insulation;

7 - concrete blind area along the perimeter of the building;

8 - finishing of the basement part of the foundation;

9 - vertical "cut-off" layer of basement waterproofing.

10 - the location of the drainage pipe (with her need).

How to correctly calculate how thick the insulation layer should be? The methodology for calculating thermal parameters is quite complicated, but two simple methods can be given that will give the required values ​​with a sufficient level of accuracy.

BUT. For a vertical section, you can use the formula for the total resistance to heat transfer.

R=df/λb + du/λp

df- the thickness of the walls of the foundation tape;

du- the desired thickness of the insulation;

λb- coefficient of thermal conductivity of concrete (if the foundation is made of another material, accordingly, the value for it is taken);

λp- thermal conductivity coefficient of the insulation;

Because λ - tabular values, foundation thickness df we also know, we need to know the meaning R. BUT this is also a tabular parameter, which is calculated for various climatic regions of the country.

Now counting t t of the required thickness of the insulation will not be difficult. For example, it is necessary to calculate the thickness of "foam" to insulate a concrete foundation with a thickness of 400 mm for Central Black Earth district (Voronezh).

According to the table we get R = 3,12.

λb for concrete – 1.69 W/m²×° FROM

λp for foam of the selected brand – 0.032 W/m²×° FROM (this parameter must be indicated in the technical documentation of the material)

Substitute in the formula and calculate:

3,12 = 0,4/1,69 + du /0.032

du \u003d (3.12 - 0.4 / 1.69) × 0.032 \u003d 0.0912 m ≈ 100 mm

The result is rounded up, in relation to the available dimensions of the insulation boards. In this case, it would be more rational to use two layers of 50 mm each - the panels laid “in the dressing” will completely block the cold penetration paths.

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

Scope and types

A monolithic slab under the house refers to floating non-buried foundations, it can also be shallow. It got its name due to the fact that the reinforced concrete base is poured under the entire area of ​​\u200b\u200bthe house, forming a large slab.

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

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

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

There are four types of slab foundation:

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

  

• Insulated Swedish stove (UShP) with built-in underfloor heating. Firstly, it differs in that the formwork of the slab is fixed - from L-shaped polystyrene foam blocks. This significantly reduces heating costs - heat leakage is minimal. Also, underfloor heating pipes are laid on top of the insulation, reinforcement is laid on them (sometimes under them) and everything is poured with concrete, the thickness of the concrete layer is 10 cm. All communications, including plumbing and sewage, are laid even at the stage of foundation preparation - in a sand cushion. That is, after the foundation is made, the heating system is ready and the engineering systems are connected. This approach allows you to speed up construction, but the foundation itself is expensive. This type of foundation requires competent engineering calculation and the same execution: when calculating and laying communications, one cannot make mistakes, since alterations are impossible. There are also questions about the repair of systems immured in the foundation. It is impossible, because expensive materials with a long guarantee are laid.

  

  UShP - insulated Swedish stove with built-in underfloor heating

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

  

  

  Insulated plate construction technology

  Saving energy is becoming a really hot topic, so few people build a foundation without insulation. Any slab foundation is a multi-layer structure, and in the case of insulation, there are even more layers. To achieve the desired level of quality, it is necessary to carefully perform each of the levels. Let's dwell on each in more detail.

  

  Foundation preparation

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

  

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

  

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

  

  Clean sand of medium grain size is poured onto the laid geotextile. Sand layer - 20-30 cm. It is poured in thin layers, evenly distributed and rammed in layers. A layer of sand that can be qualitatively compacted with a manual vibrating plate is 8-10 cm. Sand is laid in such layers. It must also be laid in a level, in an equal layer throughout the pit.

  

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

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

  

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

  Concrete preparation

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

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

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

  

  Waterproofing

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

  When laying out rolled waterproofing, it is released outside the foundation by 10-15 cm. The panels are rolled out with an overlap, the connecting edges must be smeared with bituminous mastic and pressed well. When laying out, you need to make sure that there are no creases and waves.

  If the groundwater level is high, two layers of rolled waterproofing may be needed. It is then rolled across, and also glued onto a primer (bituminous waterproofing), but you can no longer breed it.

  

  Double waterproofing of the monolithic foundation slab - coated and rolled

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

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

  Warming

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

  

  Since expanded polystyrene is “not friendly” with petroleum products, a dense plastic film is spread on it, and then heat-insulating material is already laid.

  Reinforcement

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

  From the edge of the slab, the reinforcement should be at a distance of at least 5 cm. Therefore, it is placed on special supports that provide the required clearance.

  

  When reinforcing, a cage is obtained, at each intersection the bars are tied together with a special soft steel wire. There are also connection techniques - using plastic clamps or welding. Tie with plastic clamps quickly, but not everyone trusts them. Welding is not recommended, because the weld is the most vulnerable place to rust, and the connection is too rigid. When using wire and clamps, the whole structure can “play” a little without destroying the ligament, and when welding, such movements lead to the seam bursting. As a result, the reliability of such reinforcement is low.

  Pouring the foundation slab with concrete

  The thickness of the slab is calculated for each specific case and can be from 20 cm to 50 cm. When pouring, concrete of at least grade B30 is used. The entire perimeter must be filled in one day, avoiding the appearance of vertical seams. Therefore, for concreting a slab foundation, most often concrete is brought ready-made: large volumes are required within a certain period.

  

  The schedule for the arrival of the cars must be calculated so that you have time to distribute the first portion and compact it. For compaction, building internal vibrators are used, which create high-frequency vibrations. As a result, all the air is removed, the concrete mixes better, becomes more fluid and plastic. The result of this treatment is not only a smooth concrete surface, but also a higher hygroscopic class.

  In extreme cases, you can fill the slab in horizontal layers. Vertical division in this case is unacceptable, since cracks are likely to appear at the joints.

  Curing

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

  Immediately after laying, the concrete is covered with a diaper or tarpaulin. This does not allow him to heat up from the sun, the wind does not affect him. The film is glued into large panels. The strips are laid with a stop of 10-15 cm, glued with adhesive tape. It is desirable that there are as few unglued joints as possible, that is, the shelter should consist of one or two pieces, if one is too inconvenient. In this case, individual pieces of the film overlap one another by at least half a meter.

  

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

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

  

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

  When to remove formwork

  

  Differences of the insulated monolithic Swedish plate and a video about its construction

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

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

  

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

  And also look how the Germans pour such a slab. Also a lot of useful nuances.
  

Insulation is an important part of any construction. It is necessary to isolate all external parts of the building from heat loss: walls, roof, basement and foundation. Insulation of the base of the building not only limits heat loss, but also prevents frost heaving of the soil. How is the insulation of a monolithic foundation performed? And what are the features of installing insulation on the wall and floor

Foundation insulation

Insulation of the foundation is necessary in those parts that are located in the zone of soil freezing. The basement and the top of the foundation wall are covered with insulation. In addition, heat-insulating plates are laid under the outer blind area around buildings. These measures help to protect the ground and walls from freezing and therefore avoid the earth around the house.

Different foundation designs have different ways of insulation. Tape deep - insulate only vertical walls near the surface of the earth, tape shallow - walls and soles. The pile foundation rests on non-freezing soil, therefore only the side surfaces of the piles are insulated.

Insulation of a monolithic slab of the foundation base is carried out from the sides and from below. This is necessary due to the location of the plate in the zone of soil freezing. The monolithic slab foundation is a shallow structure. The depth of its occurrence rarely exceeds 50 cm. Therefore, the entire plate is located in the zone of freezing soil and requires high-quality insulation. What materials are used to insulate the foundation slab?

Foundation insulation material: foam

The foundation insulation is subject to increased requirements for moisture and water resistance. It is in contact with moist soil, therefore, in addition to insulation, it must prevent moisture from penetrating into the walls of the house. In addition, the foundation insulation must withstand compressive loads.

The ideal material for foundation insulation is extruded polystyrene foam. The trade name of the material is penoplex. It has a closed cell structure, due to which water and moisture do not penetrate into the material and do not form its destruction. Fluctuations in temperature around zero create a variable state of "liquid-ice". When moisture is absorbed, the insulation cracks (as a result of freezing and expansion of water in the pores of the material). Therefore, ordinary expanded polystyrene (polystyrene) is not used in foundation insulation. You can use only moisture-resistant types of insulation: PPU or foam.

In addition to resistance to the penetration of moisture and steam, foam foam insulation can withstand significant compressive loads. Its price is higher than ordinary polystyrene. But it pays off with durability.

How to insulate: inside or outside?

How to properly insulate the foundation with foam plastic - from the outside or from the inside? Theoretical calculations show that the location of the insulation on the outside protects the wall and the slab from freezing. The location of the insulation inside the wall does not protect the wall and the slab, but it improves the microclimate in the room. This means that external insulation is the best option for any building surfaces.

However, it is not always possible to perform insulation from the outside. So for the foundation, external insulation is possible only at the construction stage. After isolating the base from heat loss is possible only from the inside.

Warming the foundation slab from the inside gives a noticeable positive result: the house becomes warmer and drier. At the same time, the plate itself continues to freeze in the winter season, so its durability remains small.

If the slab was insulated during construction, then the foundation does not freeze through and bears the load of the built house for a long time. How to insulate a slab foundation from the outside?

Foam insulation at the construction stage

Insulation at the construction stage involves laying insulation on the ground before pouring concrete. We list the sequence of actions for insulation during construction:

• To exclude uneven pressure of the foundation on the ground, part of the soil is removed and gravel and then sand backfill are made. A layer of sand is shed with water and carefully rammed.
• After that, a layer of waterproofing and insulation boards are laid.
• Reinforcing rods are placed on top of the insulating material and concrete is poured. At the same time, the reinforcement rods are placed in two rows, the bottom row is supported by plastic beacons (so that after pouring the reinforcement is inside the concrete).

In this way, a light, strong and warm foundation is obtained, on which the walls of the building can be erected in a month.

swedish foundation

The foundation, insulated from below with polystyrene plates and equipped with warm pipes, is called Swedish. The abbreviated abbreviation for the foundation sounds like "USHP" or Insulated Swedish Plate.

The thickness of the base plate can vary from 10 to 30 cm (depending on the type of soil and the severity of the building). The depth of such a foundation is above the soil freezing line. At the same time, frost heaving is taken under control and compensated by external insulation of the slab.

Additional arrangement of heating allows you to get a foundation and a warm floor near the house at the same time. This design saves not only weight, but also money. The amount of concrete for casting the base is reduced by a third. Reduced construction costs.

Benefits of an insulated foundation

We list the advantages that make the insulation of the foundation slab a necessary element of construction:

• Saving concrete, reducing construction costs.
• Speeding up construction time.
• Reducing heat loss and reducing utility bills.
• Improving the indoor climate.
• Increase the durability of the foundation slab and the entire structure.

Such high merits indicate that the insulated slab foundation is one of the best house foundation designs.

Foundation slab insulation updated: February 26, 2018 by: zoomfund