How to insulate a monolithic foundation. About methods of insulating a monolithic foundation slab. How can you insulate a slab foundation?

It is difficult to build a solid foundation on unstable soils. In such cases, a slab base is used. It acts as a shallow foundation, drifting across the site as soil masses move. Since the entire structure moves, no destructive stresses arise.

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

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

Choice of insulation

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

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

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

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 In this case, you will not have to change it before the coating becomes outdated.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

Often for work zero cycle Extruded polystyrene foam is used. Insulating the foundation slab with expanded polystyrene, done according to all the rules, allows you not to worry about the safety of concrete and heat conservation.

Characteristics of expanded polystyrene

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

outside;
from the inside;
in the body of concrete

External insulation technology

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

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

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

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

Expanded polystyrene boards are mounted with glue or cement-sand mortar. The first option allows for insulation when sub-zero temperatures. The underground part is secured only by gluing. This is necessary to avoid violation of the hydraulic barrier.

The base part of the insulation of the slab foundation with polystyrene foam is additionally fixed with plastic dowels. To do this, holes are drilled through the glued plates. They go through all the insulation and part of the foundation.

The glue is applied around the perimeter of the slab and in several stripes in the center. Wait for 1 minute and press the plate against the surface for a couple of minutes. After gluing, the bottom plates are sprinkled with a layer of sand. This helps secure them in the mounting position.

The second row of insulation is installed with offset seams. It is advisable to bandage the horizontal joints as well. This helps to avoid the occurrence of cold bridges.

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

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

After installation, the seams are sealed with foam. Excess foam is cut off and the surface is plastered over a mesh. The mesh is necessary for better adhesion of polystyrene foam and plaster.

Internal insulation technology

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

On top of the stove;
In the body of concrete.

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

waterproofing is installed along the foundation slab, extending onto the wall;
logs are screwed on top of the waterproofing layer;
a layer of insulation is placed between the logs;
a waterproofing film is attached to the joists on top of the insulation;
a plank base, plywood or OSB boards are mounted on the film;
A backing made of cork, foamed polyethylene or pine needles is laid on top of the subfloor. The finishing floor is mounted on it.

You can do without lag. In this case, the slab foundation is completely insulated with polystyrene foam. The material is laid in a continuous layer. The underlay and finishing floor covering are laid immediately on top of it.

When installing in concrete, the following work is performed:

the base plate is waterproofed;
An insulation layer with a thickness of at least 100 mm is installed. It is better to use products with a locking connection system;
PVC film with a density of at least 1.42 g/cm3 is laid on the insulation;
fits reinforcement mesh. Its role can be played by a masonry mesh with a cell of 100*100 mm;
the surface is filled with a screed no thinner than 5 cm;
The finishing coating is laid over the screed.

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

Insulation of the foundation slab body

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

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

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

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

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

The thermal conductivity of such a slab will be approximately 0.105 W/(m*C). The product requires additional insulation of the slab foundation from below. Thickness insulating material will be smaller, unlike plain concrete.

The choice of type and technology of foundation slab insulation depends on design features buildings and construction sites. Choose optimal solution is based on data from thermal engineering calculations and comparison of estimated costs.

When choosing a foundation structure for a future building, each developer is guided primarily by its cost, reliability and durability. The ideal foundation that combines all these qualities is monolithic foundation slabs, which can be built on various types of soil. But concrete has high thermal conductivity, so developers need to take care of insulating load-bearing structures during the construction process.

Insulation methods

Insulation of a slab foundation must be carried out in the part that is located in the soil freezing zone. The developer should lay insulation under the foundation slab, as well as under the external blind area, which must be created around the building. And also the basement of the building and the upper part of the foundation wall must be covered with special material. Timely insulation of a monolithic foundation slab will protect the soil adjacent to the building and its walls from freezing, thereby preventing frost heaving of the soil and minimizing heat loss in the house.

When planning insulation of a slab foundation, the developer must take into account the type load-bearing structure:

Tape (in-depth). For insulation, various materials are used, which are laid on the vertical surfaces of the supporting structure, above the ground surface.
Shallow strip foundation. For insulation, tile materials are used, which are laid on the sole and vertical surfaces of the supporting structure.
Pile. Only the side surfaces of piles buried in the soil are subject to insulation.
Monolithic tile construction. The foundation slab is insulated not only from below, but also from the sides.

Advantages of timely insulation

Insulated slab foundation has a large number of advantages that every developer needs to know about:

Developers will be able to save concrete mortar, which is used in large volumes when pouring slab foundation structures.
An insulated foundation allows you to minimize heat loss. This has a positive effect on the indoor microclimate, as well as on utility bills, which rapidly increase in the winter season.
The timing of construction work is being accelerated.
The useful life of the supporting structure is maximized, since it is no longer subject to the harmful effects of moisture and low temperatures.
An insulated foundation slab prevents condensation from appearing on the interior walls of the premises.
Maximizes service life waterproofing materials, which are involved in the process of constructing slab foundation structures.

What materials can be used to insulate a slab foundation?

Currently, the domestic construction market offers a huge range of materials that developers can use when carrying out insulation measures:

Polyurethane foam. This material is made of foamed plastic, which has a porous structure filled with air bubbles. This insulating mixture is created directly on construction site and is applied to foundation structures using special equipment. The components that have entered into a chemical reaction already form a strong foam on concrete surfaces, which hardens almost instantly. This material helps to minimize heat loss, prevents the penetration of extraneous noise from the street into the premises, does not undergo putrefactive changes with constant contact with a damp environment, and is highly resistant to fire.
Styrofoam. This material has been used for decades in the construction industry as insulation. Its main disadvantage is its low mechanical strength, which is why it requires additional lining.
Extruded polystyrene foam. This material has a fine cell structure and is supplied construction market in the form of sheets having rectangular shape. He has excellent technical properties, is able to withstand high loads without changing either the internal structure or geometric shape. IN last years When insulating slab foundation structures, developers use extruded polystyrene foam, since it does not require additional protection and can perform the functions assigned to it for decades.

Why do experts recommend using penoplex for insulation?

In recent years, many developers prefer to insulate the foundation with penoplex. The choice of this material is due to the fact that it is highly resistant to moisture and also has the lowest thermal conductivity. Due to the fact that the slab supporting structure will have to come into contact with a damp environment for many decades, insulating the foundation with penoplex will protect the building from its harmful effects.

Extruded polystyrene foam is ideal for thermal insulation of monolithic foundation structures, as it can withstand compressive loads. Polyurethane foam boards and penoplex are cellular materials with a closed structure, due to which moisture is not able to penetrate into their cavities. That is why they are used when carrying out insulation measures.

Rules for insulating slab foundation structures

Before insulating a slab foundation, the developer must learn about all the features and nuances, as well as the most effective technologies. If the foundation is insulated with penoplex with outside, then this will protect not only the slabs, but also the walls from freezing. In the case when polystyrene foam panels are laid with internal sides walls, the developer will be able to significantly improve the indoor microclimate, but at the same time, the slabs and walls of the building will not be protected from freezing. It follows from this that external insulation of the foundation with penoplex will be an ideal option for any construction projects.

External insulation of the foundation with expanded polystyrene or penoplex is possible only at the initial stages of construction. If developers miss this point, then in the future they will only be able to carry out internal insulation of the foundation with penoplex or polyurethane foam.

Carrying out insulation measures during the construction process

The procedure for insulating the foundation with polystyrene foam must be carried out in initial stage construction work. Developers should strictly follow the technology:

First of all, a pit is dug in which a monolithic concrete slab will be created. Its depth should be 1 meter. Recesses are made at the bottom into which drainage pipes are laid, the functions of which are to drain surface waters into specially created wells. Such measures will protect not only the foundation, but also the walls of the building from getting wet.
After installation drainage pipes The bottom of the trench is leveled and a special material, geotextile, is rolled out on its surface. It will prevent the germination of rhizomes of trees and shrubs that can disrupt the integrity of the supporting structure.
A layer of sand and crushed stone is laid on top of the geotextile. Thus, a sand-crushed stone cushion (approximately 30-40cm thick) is created at the bottom of the pit.
Utilities, such as water and sewer pipes, are laid. After laying them, the surface is sprinkled with sand and leveled.
Formwork is constructed around the perimeter of the prepared pit. For these purposes, it is customary to use boards or sheets of moisture-resistant plywood. From the outside, the formwork must be supported with jibs or stops so that the wooden structure can withstand the load that the concrete solution will exert on it.
A small amount of concrete is poured into the bottom of the pit, which will create the first foundation layer. After it hardens, the developer must begin carrying out waterproofing and thermal insulation measures.
Due to the fact that the monolithic concrete slab will constantly be in the ground and in contact with a humid environment, the developer must provide it with high-quality waterproofing. For these purposes, it is customary in the construction industry to use roll material or coating. The concrete base must be thoroughly cleaned of debris and then removed from dust. To increase its adhesive properties, it is recommended to treat it with diluted kerosene or solvent. After this, roofing material is rolled out on the prepared concrete base, the sheets of which should overlap. All joints should be treated with mastic, after which experts recommend laying another layer of waterproofing. If the developer decides to use liquid insulation, then he needs to apply it several times to the surface of the concrete base and, after complete drying, continue construction work.
At the next stage, the slab is insulated. For these purposes, most developers use sheets of extruded polystyrene foam (15 cm thick). This material is usually laid in two layers. Care must be taken to ensure that the top sheets overlap the joints of the bottom panels.
The foundation structure is being reinforced, which will increase its strength and load-bearing characteristics.
The concrete solution is poured in several stages. After pouring the first batch, the developer must use a deep vibrator to remove air and eliminate the resulting voids. After this, the remaining solution is poured out.

After the concrete has hardened, the developer can continue construction work. In order to protect the building as much as possible from the harmful effects of harmful environments, he must carry out internal insulation of the foundation. To do this, you should use sheets of extruded polystyrene foam, which are glued to the floor and walls of the premises and are subsequently finished.

An uninsulated foundation can result in greater heat loss than a tightly sealed, well-insulated home.

Insulating foundations reduces the need for high heating system output and avoids moisture condensation, which often occurs as a result of temperature differences between the inside of the basement and the soil around the foundation.

A poorly designed foundation insulation system can cause many problems, such as moisture problems and pest infestations.

Insulation of basement external walls

Installing insulation on outside plinth strip foundation has several options. External insulation has the following advantages and disadvantages:

Advantages:

Minimize thermal coupling and reduce heat loss through the foundation.
Protection against moisture penetration into interior finishing.
The insulation protects the foundation from the effects of the freeze-thaw cycle in extreme climatic conditions.
Reduced condensation.
Reduces wastage of internal space.

Flaws:

Expensive installation for an existing building if also installed drainage system along the perimeter.
Many exterior insulation materials are susceptible to pest infestations.
Many contractors are not familiar with the proper procedures in detail.

Experienced builders believe that The best way to insulate the foundation means to insulate it from the outside. Carefully designed perimeter drainage system consisting of washed gravel, perforated plastic pipe and fabric filter. Highly recommended for areas with poor soil drainage.

Some foam insulation is made with boric acid to discourage termite infestation. However, borate can slowly leach from most materials when exposed to groundwater.

Insulation of basement internal walls

In most cases, the best way is to insulate the internal walls of a strip foundation; this is also a less expensive option for finished construction. This insulation has the following advantages and disadvantages:

Advantages:

This is much cheaper than insulating external walls for existing buildings.
There are more wide choose materials, since you can use almost any type of insulation.
There is no threat of insect infestation.
A space insulated from the cold ground is more effective than using external insulation methods.

Flaws:

Many insulations require a fire resistant coating because they release toxic gases when ignited.
Reduces useful internal space by 3-5 cm.
Does not protect against moisture penetration like external insulation.
If the perimeter has poor drainage, the insulation can cause moisture to become saturated around the perimeter of the foundation and seep through the foundation walls.

New methods of foundation insulation

Some new building systems make it possible to build a ready-made insulated foundation without the use of wooden or metal formwork, this is a system concrete forms(ICF), simply put, permanent formwork made of polystyrene foam, which uses rigid foam as forms for formwork, thereby insulating the inside and outside of the foundation.

Thermal panels

Among the new products, there is also insulation that does not require finishing, this thermal panels made of polystyrene foam with stone chips.

Polyurethane foam

Other synthetic polymer material, used for thermal insulation of foundations, is polyurethane foam. It is prepared by mixing liquid components using a special technique. The production process takes place on the construction site.

Apply this material by spraying method. Cured material for 17-20sec.

One of the main advantages is the extremely low thermal conductivity of 0.028 W/m0S. In addition, the spraying method contributes to the formation of a solid layer of insulation where there are no seams (even if the foundation has complex geometry). Thus, it completely eliminates the possibility of cold bridges appearing. The spraying process itself takes much less time than installing the panels.

The disadvantage of polyurethane foam is the cost, including installation, which is more expensive than extruded polystyrene.

The strength of this material depends on its density. For basic insulation, it is recommended to use polyurethane with a density of at least 60 kg/m3.

Blocks with insulation inserts

There are also blocks with foam inserts. They are installed as blocks that do not require plaster. Some concrete block manufacturers add materials such as polystyrene or wood chips to the concrete mixture to increase the thermal resistance of their product.

Despite the fact that filling the cavity of the blocks with insulation improves their thermal properties, at the same time it does not significantly reduce heat loss compared to insulation made on the surface of the walls, or on the outer or inner parts of the foundation walls.

Studies and computer models have shown that infill block provides little heat savings because most of the heat passes through the solid parts of the walls, such as the block material and mortar.

Insulation of slab foundations

Slab foundations are often insulated along the outer edge of the slab support or between the screed and the slab. The base of the slab is often isolated from the ground. Each approach has its own advantages and disadvantages.

Insulating the outer part of the foundation or the edge of the slab reduces heat loss from both the foundation and the slab.

This method provides greater protection for the foundation from freezing. This also allows for a shallow foundation without the risk of damage from soil heaving. All exposed parts of the insulation should be covered with metal, cement or another type of membrane to protect it from damage.

When insulating a slab foundation, the insulation should be located between the support and the slab. This protects the insulation from insects and damage better than external application and insulates the slab from the cold base.

Insulating an existing slab is generally not practical.

However, you can insulate the outside of the slab from top to bottom:

Blind area.
3-8 cm of sand.
2-5 cm of rigid insulation.
A layer of polyethylene 150 microns as a moisture retarder.
10 cm of washed gravel and drainage pipes under the slab.

The insulation can be applied over the existing slab, from top to bottom, as follows:

Finish floor covering.
RIP insulation
Substrate
Rigid polystyrene foam glued with moisture-resistant strips along the joints.
Polyethylene layer 150 microns.

An alternative is a floating floor, which consists of:

Finish floor covering.
RIP insulation
2 layers of 12.5 mm thick OSB or plywood should be screwed, overlapping all the seams of the previous slab by 30-60 cm, there should be a 12.5 mm gap in the seams between the slabs to compensate for thermal expansion. The same gap must be made from the edge of the wall.
Rigid polystyrene foam glued with moisture-resistant strips along the joints.

The above methods have the following advantages and disadvantages:

Advantages:

Relatively simple installation.
The floor is insulated from the ground.
The floor surface is close to the air temperature in the room.

Flaws:

Expanded polystyrene requires fire-resistant coatings.
This can increase the depth of frost penetration along the edge of the slab in extreme climates.
In summer, the floor will not receive coolness from the ground.

Insulation of the basement floor from the inside

Insulating a basement depends on whether it has ventilation. Traditionally, basements are ventilated to avoid moisture problems. However, this method does not always work well.

If the basement must be ventilated, carefully seal all openings in the ceiling to prevent air from entering the house. Insulate the ceiling by pressing fiberglass insulation tightly to the base.

Cover the insulated surface of the floor with a vapor barrier. Carefully seal all seams to prevent air and moisture from passing through. Secure the insulation with mechanical fasteners so that it does not fall out between the joists. The insulation is attached between the beams.

Place a sheet of polyethylene, or other equivalent material, over the earthen floor. Carefully seal all seams with tape. Cover the plastic sheeting with a layer of sand or concrete to protect it from damage. Do not fill the film with anything that could make holes in it, such as crushed gravel.

If the basement is not ventilated, then all of the above is done + insulation of the walls and floor.

To begin with, the location of the foundation for the building is marked on the building site.
The top layer of continental soil must be removed to the depth of laying the foundation slab, the bottom of the excavation must be as smooth as possible.
The prepared area is filled with coarse sand, which must be compacted using vibrating rammers. A small layer of concrete is poured over the layer of sand, for which it is exposed.
After the concrete screed has hardened, lay out the insulation from polystyrene foam boards, making sure that the mounting grooves match as much as possible. Large gaps should not be allowed between the insulation boards.
A layer of polyethylene film is laid on top of the laid polystyrene slabs, which is glued together using special tape.
Construction formwork is being erected for pouring the slab base into which it is mounted spatial frame from reinforcement with a diameter of 10 mm. Concrete is poured from the corner of the slab foundation, evenly leveled and compacted using a vibrator.
The foundation slab gains strength in about 28 days, the formwork can be dismantled two weeks after the structure is poured - by this time the foundation has gained up to 70% strength.
The side walls of the foundation slab are additionally insulated with expanded polystyrene slabs.

An insulated monolithic slab will last for many years without structural damage from exposure to adverse factors.

Insulating the slab of any foundation is one of the most important things when building a house. This is best done in the warm season, and should not be done in rainy weather. Insulation of a monolithic foundation slab is especially important for cold regions where the soil freezes at great depths. When heaving soils freeze, they 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 heat loss throughout 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 last. And most importantly, the house will remain warm even in severe frosts. Do not forget that most of the cold enters the house through the foundation. And if the building has a basement (billiard room, gym), then care should be taken about internal insulation. This is especially important if the basement is not heated. But the most important thing is external insulation any residential building.

The main reasons why insulation is necessary:

Increasing waterproofing properties.
Reduced heat loss.
Reducing home heating costs.
Preventing the formation of condensation on the walls.
Stabilization of the internal temperature of the building.

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

What insulation should I use for the foundation?

The most an important part work when insulation of a fresh foundation slab is required is the selection of suitable material. It should not deform under soil pressure and absorb moisture. These are the most important parameters any thermal insulation. These won't fit soft materials like mineral wool. 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 during 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, since it must be sprayed. For complete insulation, 50 mm of insulation thickness, laid in several layers, is sufficient. All joints must be sealed after insulation.

This material has a number of positive properties:

low thermal permeability;
good adhesive properties;
reliability;
durability.

And the main thing is that when using polyurethane foam, there is no need to use additional means for steam, water and waterproofing. It has only one drawback - the need to use special equipment. Therefore, this method of insulation will require either considerable investment or the help of experienced specialists with appropriate equipment.

Extruded polystyrene foam

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

high strength;
long term services;
reliable thermal insulation properties.

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

Extruded polystyrene foam with grooves

This new variety insulation. Milling grooves on the surface of polystyrene foam slabs are excellent for insulating the foundation. Used in conjunction with geotextile fabric as fastener drainage. Its main properties:

good thermal insulation;
protective layer of waterproofing;
waterproof.

Foundation insulation 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 effective and less expensive, and most importantly, it is easy to install. Before proceeding with its installation, it is recommended to lay waterproofing, then you can begin laying extruded polystyrene foam slabs.

The most effective method of insulating a foundation using this material is to use it in areas where the soil freezes. The insulation is installed to the freezing depth. This is quite enough. When insulating, special attention should be paid to the corners: in such places, the polystyrene foam used should be thicker than in other areas. It is imperative to insulate the soil around the perimeter of the building. To do this, it is necessary to place insulation under the blind area structure.

All rows of extruded polystyrene foam boards must be laid end-to-end, from bottom to top. Large seams are filled with polyurethane foam. This will ensure high tightness, thermal insulation and waterproofing properties. The slabs are placed on polymer glue or mastic, and then pressed with a layer of soil. When insulating, it is important to take into account that all slabs are the same width; you cannot use already used material, this may break 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 breaks or gaps. The insulation must form completely closed loop. This will allow you to achieve maximum thermal insulation properties. It is sprayed onto the foundation using special equipment. The material then hardens within 20 seconds. In general, the entire process of installing insulation is quite simple and quick. The application of polyurethane foam is done in several layers, after each of them has dried. One layer should be approximately 15 mm thick.

Upon completion of all work, it is done with soil. Equipment for installing such insulation can be purchased in specialized stores or rented. But it’s easier and faster to use the services of professionals.

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

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

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

Choice of insulation

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

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

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

Often, extruded polystyrene foam is used for zero-cycle work. Insulating the foundation slab with expanded polystyrene, done according to all the rules, allows you not to worry about the safety of concrete and heat conservation.

Characteristics of expanded polystyrene

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

outside;
from the inside;
in the body of concrete

External insulation technology

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

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

Expanded polystyrene boards are mounted with glue or cement-sand mortar. The first option allows for insulation at sub-zero temperatures. The underground part is secured only by gluing. This is necessary to avoid violation of the hydraulic barrier.

The second row of insulation is installed with offset seams. It is advisable to bandage the horizontal joints as well. This helps to avoid the occurrence of cold bridges.

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

After installation, the seams are sealed with foam. Excess foam is cut off and the surface is plastered over a mesh. The mesh is necessary for better adhesion of polystyrene foam and plaster.

Internal insulation technology

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

On top of the stove;
In the body of concrete.

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

waterproofing is installed along the foundation slab, extending onto the wall;
logs are screwed on top of the waterproofing layer;
a layer of insulation is placed between the logs;
a waterproofing film is attached to the joists on top of the insulation;
a plank base, plywood or OSB boards are mounted on the film;
A backing made of cork, foamed polyethylene or pine needles is laid on top of the subfloor. The finishing floor is mounted on it.

When installing in concrete, the following work is performed:

the base plate is waterproofed;
An insulation layer with a thickness of at least 100 mm is installed. It is better to use products with a locking connection system;
PVC film with a density of at least 1.42 g/cm3 is laid on the insulation;
reinforcement mesh is laid. Its role can be played by a masonry mesh with a cell of 100*100 mm;
the surface is filled with a screed no thinner than 5 cm;
The finishing coating is laid over the screed.

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

Insulation of the foundation slab body

Polystyrene concrete with a density of D1200 is used for constructing structural elements. When preparing 1 cube, the composition includes:

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

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

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

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, but in difficult cases it can be expensive.

Scope and types

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

A prerequisite is the presence of a sand and gravel cushion, which redistributes the load from the house to the ground and serves as a damper 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 construction of a monolithic slab foundation is simple and reliable, but its production requires a large amount of reinforcement and large volumes of high-grade concrete (not lower than B30), because the entire area occupied by the building is reinforced and concreted, and with a margin for greater stability. That’s why such a foundation is considered expensive. In principle, this is true, but it must be considered. In some cases, its cost is lower than deep tape laying - due to the smaller volume earthworks and less concrete.

The depth of the monolithic slab is determined depending on the weight of the house and the type of soil. With shallow depth on heaving soils in winter, the house along with the base can rise and fall. If the reinforcement and slab thickness are correctly calculated, this does not affect the integrity of the building. The plate compensates for all changes due to elastic force. In the spring, after the soil has melted, the house “sits” into place.

There are four types of slab foundations:

Classical. Reinforced concrete slab sits on a sand and gravel bed 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 cushion depends on the depth of the fertile layer - it must be completely removed. The resulting pit can be filled 2/3 with sand and gravel.
Insulated Swedish stove (USH) with built-in heated floor. Firstly, it differs in that the slab formwork is permanent - made of L-shaped polystyrene foam blocks. This significantly reduces heating costs - heat loss is minimal. Also, heated floor pipes are laid on top of the insulation, reinforcement is laid on them (sometimes under them), and everything is filled with concrete, the thickness of the concrete layer is 10 cm. All communications, including water supply and sewerage, are laid at the stage of preparing the foundation - in a sand cushion. That is, after making the foundation, the heating system is ready and the engineering systems. This approach allows you to speed up construction, but the foundation itself is expensive. This type of foundation requires competent engineering calculations and the same execution: you cannot make mistakes when calculating and laying communications, since alterations are impossible. Questions also arise regarding the repair of systems immured in the foundation. It is impossible, so they use expensive materials with a long warranty.
USHP - insulated Swedish stove with built-in heated floor
Russian - a plate with stiffening ribs. 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 stiffeners. They are usually arranged under load-bearing walls. In this case, the complexity of the work increases - the stiffeners are installed separately, and the slab separately. But load bearing capacity such a foundation is much higher, which makes it possible to reduce the thickness of the slab to 10-15 cm.

Construction technology of insulated slab

Energy savings are becoming real hot topic, so few people build a foundation without insulation anymore. 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, each level must be carefully completed. Let's look at each in more detail.

Preparing the base

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

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

The bottom is leveled, the holes are filled in, the humps are removed, everything is carefully leveled to the horizon level and compacted. Roll 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, which serves as a damping pad, from being washed away.

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

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

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

At this stage, sewer and water pipes. Ditches of the required depth are dug in the already compacted crushed stone. They should be such that there is some space around the embedded elements. Pipes are laid in the ditches, filled with sand, leveled, and the sand is compacted with a shovel or board. More severe compaction may lead to cracks. That’s why the pipes are laid after compaction.

Concrete preparation

Formwork is placed around the perimeter of the pit. It is usually assembled from 40 mm thick boards or 18-21 mm plywood. The height of the formwork for a monolithic slab is the total thickness of the remaining layers. Along its edge it is convenient to control the level of concrete when pouring, so the board must be edged. To save material, you can set up the formwork only for preparation. After the concrete has set, it is dismantled and placed higher, reused to fill 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 100 mm layer of concrete is poured onto the compacted gravel. This can be low grade concrete - 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 roll. The base is first thoroughly dust-free, then impregnated with diluted kerosene or solvent primer (and the sides of the concrete preparation are also coated). It is sold very thick and does not adhere well to concrete. As a result, the roll waterproofing adheres poorly and the foundation will get wet. When diluted, it becomes more fluid and penetrates deeper into the concrete. At the same time, it almost does not lose its properties.

When laying out rolled waterproofing, it is released 10-15 cm beyond the foundation. The panels are rolled out with an overlap, the connecting edges must be coated bitumen mastic and press well. When laying out, you need to make sure that there are no creases or waves.

If the groundwater level is high, two layers of roll waterproofing may be needed. It is then rolled out crosswise and also glued onto a primer (bitumen waterproofing), but it can no longer be thinned.

Double waterproofing of a monolithic foundation slab - coating and roll

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

Capillary suction of moisture through the slab can also be reduced using liquid impregnations such as Betonite. It significantly reduces moisture absorption. Penetrates to a depth of 50-60 cm, so it saturates the concrete preparation through and through. The disadvantage of this material is its high price, but the properties of the material are excellent.

Insulation

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

Since polystyrene foam is not friendly with petroleum products, a thick polyethylene film is spread on it, and then heat-insulating material is laid.

Reinforcement

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

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

When reinforced, a cage is obtained; at each intersection, the rods are tied together with a special soft steel wire. There are also connection techniques - using plastic clamps or welding. Plastic clamps are quick to tie, but not everyone trusts them. It is not recommended to use welding, because the weld seam is the most vulnerable place to rust, and the connection is too rigid. When using wire and clamps, the entire 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, use concrete of at least grade B30. The entire perimeter must be filled in one day, avoiding the appearance of vertical seams. Therefore, for concreting a slab foundation, ready-made concrete is most often delivered: large volumes are required within a certain period of time.

The arrival schedule of the vehicles must be calculated so that you have time to distribute the first portion and compact it. For compaction, construction deep vibrators are used, which create high-frequency vibrations. As a result, all 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 hygroscopicity class.

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

Curing

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

Immediately after laying, the concrete is covered with a diaper or tarpaulin. This prevents it from heating up from the sun, and the wind does not affect it. The film is glued into large panels. The strips are laid with an overlap of 10-15 cm and taped with tape. It is desirable that there be as few unlined joints as possible, that is, the shelter should consist of one or two pieces, if one is too inconvenient. In this case, individual pieces of film overlap each other by at least half a meter.

The dimensions of the film are such that the side surface of the formwork is also covered, and a load can be placed on the edges of the film, which will prevent the wind from lifting it. Also, with a load - boards - they press the place where the two panels overlap to reduce 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. To avoid damaging the surface with drops, you can lay burlap on it or sprinkle a layer of sawdust and cover it with film on top. The covering material is watered, and it maintains the moisture content of the concrete. In any case, watering is carried out only at temperatures above +5°C.

If there is a threat of 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 available materials.

When to remove formwork

Differences between an insulated monolithic Swedish slab 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, permanent formwork made of extruded polystyrene foam is used. As a result, heat leakage into the ground is minimal. The second fundamental difference is the water heated floor system built into the slab.

Since engineering systems are poured deep into concrete, it requires accurate and competent calculations. High demands are also placed on execution. Even small mistakes are critical. You can make USP yourself, but it is better to order the project. See the following photo for an approximate breakdown of costs. The amounts are no longer relevant, but the percentages are correct. The cost of the foundation project is about 1%.

In the following videos you will see the stages of making a Swedish stove for a specific house. Many useful devices are described that will make work easier, and explanations are given for some of their features.

And look how the Germans pour such a slab. There are also many useful nuances.

The construction of a house begins with laying the foundation. Thermal insulation of a house should also begin with it. Insulating the foundation of a house with extruded polystyrene foam is an effective, time-tested way to preserve heat in a room. The technology is easy to learn, although the method is not budget-friendly.

Types of material

Expanded polystyrene appeared at the beginning of the 20th century and was patented in 1928. This is quite an interesting material, widely used in construction. The main quality is the ability to retain heat.

Many people consider expanded polystyrene and polystyrene foam to be the same material, which is incorrect. It differs from polystyrene foam: it is more durable, resistant to external influences, and homogeneous. Its cost is higher than that of conventional foam.

Expanded polystyrene is produced by adding gas to the polymer mass. When heated, it increases. Depending on the type of material, different gases are used. Simple forms materials are created from gas of natural origin. More complex ones are filled with carbon dioxide.

Pressless is the most common type. Drying removes all moisture. Next, at a temperature of 80 degrees, foaming occurs, followed by drying and heating. Ready mixture poured into a mold where the polystyrene foam hardens. Obtained by this method is considered brittle. Its preparation requires less isopetane, which makes the final cost of the product affordable for most.
Extruded – similar with a pressless appearance. The difference is in the use of equipment. In this case, an extruder is used, after which the type of material is named.
Extrusion is created as a result of processing the final mass. Used for preparing disposable tableware and packaging.
Pressing is the most expensive method of creating expanded polystyrene. After foaming the mass, processing with a press is provided. This makes it more durable and strong.
Autoclave is less common. Manufacturing takes place in an autoclave.

Types of expanded polystyrene

Each type has its own advantages that set it apart from the rest. The safety aspect for humans is important.

Harmful or harmless

There are supporters and opponents of this material. Those who are in favor of it talk about the environmental friendliness and safety of polystyrene foam, citing scientific research as evidence.

Due to the stability of the molecular structure under normal conditions of use, it is absolutely safe for human health, which has been proven in experiments.

The use of the material in the temperature range from -40°С to +40°С also does not affect the condition in any way environment.

Opponents insist that when burned, polystyrene foam releases styrene, which is a poison and can worsen your health: dizziness, pain in the eyes, the possibility of poisoning, and more.

Styrene can only be released at high temperatures. It is found in small quantities in coffee, strawberries, tea and other foods.

Its harm and harmlessness depend mainly on the conditions of use, and not on the quality of the material itself.

Professionals choose extruded polystyrene foam

For example, it cannot be used to insulate a metal roof. The metal heats up from the sun's rays, and the material can begin to melt, releasing styrene. Mineral wool – more suitable option for this.

Many people insulate the walls of the house from the inside, which is also not recommended. This situation is fraught with the formation of mold and mildew on the walls, which will negatively affect the health of people living in such a room. This is caused by moisture accumulation in the polystyrene foam.

It is best suited for insulating the outside of a house, including the foundation.

Advantages, cost, technical characteristics

Expanded polystyrene has the following indicators:

Thermal insulation. This material retains heat well. But compared to mineral wool he is lower. The level varies from 0.028 to 0.034 W x m x Kelvin. The high density of polystyrene foam ensures good heat conductivity.
Moisture resistance, vapor permeability. Depending on the type of material, it has varying degrees of vapor permeability. For example, the extruded material parameter is zero. Foam has from 0.019 to 0.015 kg per meter-hour - Pascal. Regarding resistance to moisture, when a sheet of polystyrene foam is immersed in a container of water, only 4% of the total liquid will be absorbed. In the case of a denser material texture - ten times less.
Strength. According to this characteristic, extruded material is the leader. Here it has no competitors: strong molecular bonds create strong, high-quality material.
Impact resistance. Only direct rays of the sun have a destructive effect on it; this should be taken into account when using it.
The service life is quite long. When the temperature changes, it retains its original properties and is not subject to deformation.
Environmental friendliness. The product is susceptible to oxidation. Even after installation of the material, an oxidation process occurs. It is associated with the inability of the material to polymerize during the production process, which is why it occurs later.

Insulation in slabs

The main criterion for insulation remains the ability to protect the room from the cold. This is exactly what needs to be taken into account when deciding to insulate the foundation.

Before making a choice in favor of expanded polystyrene, you should carefully familiarize yourself with its advantages and disadvantages.

The benefits include:

Possibility of use in various forms. When melted, it is easy to give the desired shape.
Expanded polystyrene has a wide range of colors
Suitable as a material for insulating any buildings.
Economical to use.
Wide scope of application.
Recyclable.

The disadvantages of the material are:

Ease of ignition.
Obsolete types of material contain harmful substances released when heated to high temperatures.
A long period of decomposition, and therefore environmentalists oppose its use.
High processing costs.
Easily broken.

Ease of ignition

Like any material, the feasibility of its use also depends on the financial burden. The cost consists of several indicators:

Brands, type of material.
Manufacturer's brand.
Densities.
Sizes of the finished product.

The scheme for determining the cost of insulation in the end will depend on the area of residence. In order to save money, many people insulate the foundation with their own hands. If planned additional insulation base, you will have to increase the consumption of material, which incurs additional costs. The total cost can be calculated according to the following scheme: the number of sheets is multiplied by the cost of insulation per square meter. Extruded will cost more than usual, but its thermal insulation quality is better.

The main stages of the process of insulating the foundation with polystyrene foam yourself

To independently insulate the foundation with polystyrene foam, you will need the following tools:

The material itself is polystyrene foam.

For outdoor work:

Special glue for installation.
Primer for leveling surfaces.
Corners with perforation made of metal.

A hammer drill with a drill, 1 cm in diameter. The length is selected based on the thickness of the insulation material, no more than 7 - 8 cm.
Special mixer for construction.
Construction level.
Stationery knife.

Tools for working with polystyrene foam

Insulating the foundation of a house with polystyrene foam consists of the following steps:

The trench is backfilled: a sand layer up to 20 cm thick is laid on the bottom and compacted properly.
It is necessary to isolate the base from water. For this, bitumen or a special waterproof mastic is used.
Determine the horizontal level by which the height of the polystyrene sheets is determined.
Now you can start installing the slabs. For this purpose, foam or installation adhesive must be used.
The cracks are treated with foam for installation. The remains are cut off with a knife.
Reinforcement of a layer for thermal insulation. In this case, the mesh is connected to the top of the slab and fixed with glue. This will protect the material from external mechanical damage.
The upper edge of the thermal insulation material must be processed. The glue is applied in a continuous layer.
Backfilling the trench with earth. It happens in layers. The size of each layer is 30 cm.
In the case where the foundation is completely located underground, it is enough to fill the trench. If the foundation has a ground part, then it is finished facing material: tiles, siding, porcelain tiles and others.

Technology of laying insulation on the foundation

Insulation of the strip foundation of a building with polystyrene foam will proceed a little differently. Polystyrene foam is not afraid of water, but waterproofing is also placed under it. The use of foam plastic when insulating strip foundations is justified by the fact that the loads on the insulation are serious. If the soil is dry or clayey, it can be safely installed. It will cope with the load even after the house shrinks.

For more wet soil a large thickness of polystyrene foam will be required, which is also selected depending on temperature regime winter.

The technology for insulating the foundation for each type will be slightly different, but the basic principle is the same.

Thus, insulating the foundation of a house with polystyrene foam is an important part of the entire construction of a house. The material is resistant to damage, has excellent insulating properties: does not allow moisture to pass through, retains heat. It is practically safe for human health and the environment. There is a range of materials on the market in different shades and qualities. Everyone will be able to choose what they need and what suits their financial capabilities.

Source: znatoktepla.ru

Insulation of slab foundations

Insulation methods

When planning the insulation of a slab foundation, the developer must take into account the type of supporting structure:

Tape (in-depth). For insulation, various materials are used, which are laid on the vertical surfaces of the supporting structure, above the ground surface.
Shallow strip foundation. For insulation, tile materials are used, which are laid on the sole and vertical surfaces of the supporting structure.
Pile. Only the side surfaces of piles buried in the soil are subject to insulation.
Monolithic tile construction. The foundation slab is insulated not only from below, but also from the sides.

Advantages of timely insulation

An insulated slab foundation has a large number of advantages that every developer needs to know about:

Developers will be able to save concrete mortar, which is used in large volumes when pouring slab foundation structures.
An insulated foundation allows you to minimize heat loss. This has a positive effect on the indoor microclimate, as well as on utility bills, which rapidly increase in the winter season.
The timing of construction work is being accelerated.
The useful life of the supporting structure is maximized, since it is no longer subject to the harmful effects of moisture and low temperatures.
An insulated foundation slab prevents condensation from appearing on the interior walls of the premises.
The service life of waterproofing materials, which are used in the process of constructing slab foundation structures, is maximized.

What materials can be used to insulate a slab foundation?

Currently, the domestic construction market offers a huge range of materials that developers can use when carrying out insulation measures:

Polyurethane foam. This material is made of foamed plastic, which has a porous structure filled with air bubbles. This insulating mixture is created directly at the construction site and applied to foundation structures using special equipment. The components that have entered into a chemical reaction already form a strong foam on concrete surfaces, which hardens almost instantly. This material helps to minimize heat loss, prevents the penetration of extraneous noise from the street into the premises, does not undergo putrefactive changes with constant contact with a damp environment, and is highly resistant to fire.
Styrofoam. This material has been used for decades in the construction industry as insulation. Its main disadvantage is its low mechanical strength, which is why it requires additional lining.
Extruded polystyrene foam. This material has a fine-cell structure and is supplied to the construction market in the form of rectangular sheets. It has excellent technical properties and is able to withstand high loads without changing either the internal structure or geometric shape. In recent years, when insulating slab foundation structures, developers have been using extruded polystyrene foam, since it does not require additional protection and can perform its intended functions for decades.

Extruded polystyrene foam is ideal for thermal insulation of monolithic foundation structures, as it can withstand compressive loads. Polyurethane foam boards and penoplex are cellular materials with a closed structure, due to which moisture is not able to penetrate into their cavities. That is why they are used when carrying out insulation measures.

Rules for insulating slab foundation structures

Before insulating a slab foundation, the developer must learn about all the features and nuances, as well as the most effective technologies. If the foundation is insulated with penoplex from the outside, this will protect not only the slabs, but also the walls from freezing. In the case when polystyrene foam panels are laid on the inside of the walls, the developer will be able to significantly improve the indoor microclimate, but at the same time, the slabs and walls of the building will not be protected from freezing. It follows from this that external insulation of the foundation with penoplex will be an ideal option for any construction projects.

External insulation of the foundation with expanded polystyrene or penoplex is possible only at the initial stages of construction. If developers miss this point, then in the future they will only be able to carry out internal insulation of the foundation with penoplex or polyurethane foam.

Carrying out insulation measures during the construction process

The procedure for insulating the foundation with expanded polystyrene must be carried out at the initial stage of construction work. Developers should strictly follow the technology:

First of all, a pit is dug in which a monolithic concrete slab will be created. Its depth should be 1 meter. At the bottom, depressions are made into which drainage pipes are laid, the functions of which are to drain surface water into specially created wells. Such measures will protect not only the foundation, but also the walls of the building from getting wet.
After laying the drainage pipes, the bottom of the trench is leveled and a special material, geotextile, is rolled out on its surface. It will prevent the germination of rhizomes of trees and shrubs that can disrupt the integrity of the supporting structure.
A layer of sand and crushed stone is laid on top of the geotextile. Thus, a sand-crushed stone cushion (approximately 30-40cm thick) is created at the bottom of the pit.
Utilities, such as water and sewer pipes, are laid. After laying them, the surface is sprinkled with sand and leveled.
Formwork is constructed around the perimeter of the prepared pit. For these purposes, it is customary to use boards or sheets of moisture-resistant plywood. From the outside, the formwork must be supported with jibs or stops so that the wooden structure can withstand the load that the concrete solution will exert on it.
A small amount of concrete is poured into the bottom of the pit, which will create the first foundation layer. After it hardens, the developer must begin carrying out waterproofing and thermal insulation measures.
Due to the fact that the monolithic concrete slab will constantly be in the ground and in contact with a humid environment, the developer must provide it with high-quality waterproofing. For these purposes, in the construction industry it is customary to use rolled or coating material. The concrete base must be thoroughly cleaned of debris and then removed from dust. To increase its adhesive properties, it is recommended to treat it with diluted kerosene or solvent. After this, roofing material is rolled out on the prepared concrete base, the sheets of which should overlap. All joints should be treated with mastic, after which experts recommend laying another layer of waterproofing. If the developer decides to use liquid insulation, then he needs to apply it several times to the surface of the concrete base and, after complete drying, continue construction work.
At the next stage, the slab is insulated. For these purposes, most developers use sheets of extruded polystyrene foam (15 cm thick). This material is usually laid in two layers. Care must be taken to ensure that the top sheets overlap the joints of the bottom panels.
The foundation structure is being reinforced, which will increase its strength and load-bearing characteristics.
The concrete solution is poured in several stages. After pouring the first batch, the developer must use a deep vibrator to remove air and eliminate the resulting voids. After this, the remaining solution is poured out.

Source: rumydom.ru

Insulation of the foundation with polystyrene foam: technology for insulating the foundation of a house from the outside

Thermal insulation of a home must begin from the foundation, and the best material This is what polystyrene foam is for. Insulating the foundation with polystyrene foam is a 100% proven option, + the video will help you master the technology. And although this method not the cheapest, but very effective, and also quite simple to implement.

Foundation insulation with polystyrene foam

Insulation characteristics

Expanded polystyrene sheets have a large number of positive properties:

it is light;
moisture resistant;
environmentally friendly;
insects do not grow in it;
does not mold or rot;
has high compressive strength;
absorbs sounds;
does not allow heat to pass through.

In addition, this material is easy to install and lasts about 40 years if the thermal insulation is carried out according to all the rules. Expanded polystyrene also has disadvantages:

the material is fire hazardous;
subject to mechanical damage;
destroyed by exposure to UV.

To attach polystyrene foam sheets, do not use organic solvent glue or hot mastic. To protect the insulation from damage, it must be transported and unloaded carefully, not thrown from a height, and be sure to close it after installation. exterior decoration- tiles, siding, plaster or at least cement mortar.

Technical characteristics of sheet polystyrene Indicator Temperature range of operation of sheets that do not experience mechanical loads (C°) from -18 to +60 Density (kg/m3) 1040 - 1060 Hardness (MPa) 120 - 150 Softening temperature (Vic) in air ( С°) 85 Softening temperature (Vic) in a liquid medium (С°) 70 Tensile strength, MPa (kgf/cm2), not less for sheets with a nominal thickness up to 3.75 mm inclusive 17.7 (180) Tensile strength , MPa (kgf/cm2), not less for sheets with a nominal thickness over 3.75 mm 16.7 (170)

Prices for popular types of insulation

Preparatory stage

First you need to calculate how many insulation boards will be needed for the foundation. The dimensions of a standard polystyrene foam board are 600x1200 mm, thickness from 20 to 100 mm. For the foundation of a residential building, slabs 50 mm thick are usually used, laid in two layers. To find out how many slabs will be needed, the total length of the foundation is multiplied by its height and divided by 0.72 - the area of one sheet of polystyrene foam.

For example, if a 2 m high foundation is insulated in a 10x8 m house, the thermal insulation area is equal to 72 square meters. Dividing it by 0.72, we get the number of sheets - 100 pieces. Since the insulation will be carried out in two layers, it is necessary to buy 200 slabs 50 mm thick.

This, however, is a very average calculation, based on the fact that the insulation thickness will be exactly 100 mm. But this value can be greater - it all depends on the climatic conditions of the region, the foundation material, and the type of insulation.

There is a special system for calculating thickness, which requires knowing the R index - this is a constant value of the required heat transfer resistance established by SNiP for each region. You can check it with your local architecture department, or take it from the table below:

City (region) R - required heat transfer resistance m2×°K/W Moscow 3.28 Krasnodar 2.44 Sochi 1.79 Rostov-on-Don 2.75 St. Petersburg 3.23 Krasnoyarsk 4.84 Voronezh 3.12 Yakutsk 5.28 Irkutsk 4.05 Volgograd 2.91 Astrakhan 2. 76 Ekaterinburg 3.65 Nizhny Novgorod 3.36 Vladivostok 3.25 Magadan 4.33 Chelyabinsk 3.64 Tver 3.31 Novosibirsk 3.93 Samara 3.33 Perm 3.64 Ufa 3.48 Kazan 3.45 Omsk 3.82

Calculator for calculating the thickness of foundation insulation

In order not to bother the reader with calculation formulas, below is a special calculator that will allow you to quickly and accurately find the required thermal insulation thickness. The result obtained is rounded up, leading to the standard thickness of the panels of the selected insulation:

Source: stroyday.ru

Features of foundation insulation with extruded polystyrene foam

Master class on working with EPS when insulating various types of foundations.

As part of the “HOUSE IN A YEAR” project with FORUMHOUSE, a modern energy-efficient cottage is being built on a USP foundation. One of the important stages of installation of this type of foundation is proper insulation. How the foundation of our house was insulated can be seen in the history of the project.

The purpose of this article is to go beyond the scope of this project and tell, on behalf of specialists, the basic rules for working with the material that can be useful to everyone.

When constructing this type of foundation, extruded polystyrene foam (EPS) was used. In a master class format, professional builders will tell you how to choose and how to properly work with extruded polystyrene foam when insulating various types of foundations. Namely:

Why is it necessary to insulate the foundation?
What to look for when choosing a material for foundation insulation.
How to properly secure extruded polystyrene foam to the foundation.
What tool is needed for the job?

Why is it necessary to insulate the foundation?

The foundation is the underground part of the structure that transfers the load from the overlying structures to the prepared soil foundation. Foundations are of the following types:

Slab, shallow, with spatial reinforcement. This gives the structure rigidity and allows it to withstand loads arising from uneven soil movement without internal deformation.

Tape - laid below the freezing depth, etc. MZLF is a shallow strip foundation, with a base depth above the calculated level of seasonal soil freezing.

USHP. Insulated Swedish Plate. This foundation is a monolithic concrete slab, mounted on a base insulated with extruded polystyrene foam. A water system is integrated into the foundation underfloor heating and all engineering communications.

This type of foundation is considered the most technologically advanced and energy efficient. One system combines the foundation and a low-temperature heating system, eliminating the formation of local overheated zones and providing comfortable radiant heat. In addition, the foundation is not exposed to the forces of frost heaving, because Anti-heaving measures have been carried out. Namely, the heaving soil was excavated and replaced with non-heaving soil (sand or crushed stone), a drainage system was installed, the blind area and the base of the slab were insulated.

To achieve maximum energy efficiency of a building, it is necessary to create a closed insulated loop. This means that, in addition to the main structures, such as walls, roof and basement, it is also necessary to thermally insulate the foundation.

In some cases, it is enough to insulate the floor and basement, but when organizing a used basement thermal insulation of foundation walls is prerequisite to achieve the required level of comfort and reduce heat loss.

In shallow strip and slab foundations, thermal insulation can reduce the effect of frost heaving. Soil heaving is formed due to the freezing of water in the soil and its subsequent expansion. Different soils have different degrees of heaving. For example, sands allow water to pass through them well, and it does not linger in them. Clay, on the contrary, does not allow water to escape, and due to the presence of a large number of small pores, it has a high capillary suction of moisture. Improper design on heaving soils can lead to serious consequences, including destruction of the foundation. If you leave the foundation uninsulated, the heat flow will go down and warm the soil, protecting it from freezing. However, the house may not be heated constantly, and in this case the soil heaves. Thermal insulation of the foundation and blind area is one of the measures to combat frost heaving.

Basic principles for choosing thermal insulation for foundation insulation

So, summarizing all of the above, we conclude: the foundation needs to be insulated. Not every insulation is suitable for this, but only material that can work in aggressive conditions external environment. Those. thermal insulation designed to be “non-removable” must be moisture resistant, have a long service life during which it will not lose its thermal insulation properties, and have strength sufficient to withstand the load from the overlying structures.

Extruded polystyrene foam (EPS) has a low thermal conductivity coefficient of 0.028 W/(m*°C) and a minimum water absorption coefficient of 0.2% by volume. The insulation does not absorb water, is chemically resistant and does not rot. Compressive strength at 2% linear deformation – not less than 150 kPa (

15 t/sq. m) and higher. Service life in soils is at least 50 years.

The thickness of the thermal insulation layer should be taken based on calculations based on several conditions:

Purpose of the building (residential, administrative, industrial, etc.).
The insulation must provide the required heat transfer resistance for a given type of building.
There should be no seasonal moisture accumulation in the structure.

Calculation thickness of thermal insulation for the foundation is made according to the methodology set out in SP50.13330.2012 “Thermal protection of buildings”. For different regions, the thickness of thermal insulation may vary, depending on climatic conditions. It should also be taken into account that increasing the thickness of thermal insulation increases the energy efficiency of the building and, therefore, leads to lower heating costs.

When choosing technical characteristics of thermal insulation, we are guided by the following principles:

When thermally insulating a strip foundation, when only the vertical wall is insulated, increased strength of the material is not required, because in this case, the EPS takes up loads only from the backfill soil. Therefore, for shallow foundations, brands of extruded polystyrene foam with a compressive strength (at 10% linear deformation) of 150-250 kPa are suitable.
When laying EPS slabs under the base of the foundation or under the slab, the loads on it increase significantly, and accordingly, the requirements for its strength increase. In this case, it is recommended to use thermal insulation boards with a compressive strength of 250 - 400 kPa.
A material has been developed specifically for USP with a compressive strength at 10% deformation of 400 kPa and increased slab sizes to increase installation speed. In addition, the increased dimensions of the slabs make it possible to reduce the number of seams and, accordingly, increase the uniformity of the layer.

The nuances of installing extruded polystyrene foam when insulating the foundation

Insulation of the EPPS foundation, depending on its design, should be divided into a number of sequential steps:

Preparing the base. When insulating an EPS strip foundation, the walls must be smooth, free of dirt and concrete deposits. If necessary, we remove uneven surfaces and cover up sinkholes, chips, etc. cement-sand mortar.

Choosing a method of fastening EPS. To attach the insulation, we use polymer-cement mixtures or, to speed up installation, special polyurethane adhesive foam.

Adhesive foam is applied in a strip approximately 3 cm thick along the entire perimeter of the slab, as well as in one strip in the center of the insulation.

The distance of the adhesive foam strip from the edge of the slab is at least 2 cm.

Before installing the slab, wait 5-10 minutes and only then glue it to the foundation wall.

We foam the gaps between the plates (if they exceed 2 mm).

If mechanical fixation of thermal insulation is provided, then the number of dowels is calculated as follows - for fastening 1 sq. m of thermal insulation on the central part of the foundation requires 5 pieces. fasteners We fix the EPS on the corner parts of the foundation at the rate of 6-8 dowels per 1 sq. m.

When insulating the base of a strip foundation or monolithic slab, EPS is laid loosely on a prepared base (usually on a compacted sand bed). In this case, it is enough to foam the seams with adhesive foam and, if necessary, fasten adjacent thermal insulation boards together. You can use a nail plate for this.

Depending on the type of foundation, there are different ways to fix extruded polystyrene foam. If it is necessary to insulate the vertical part of the foundation, on which a waterproofing layer has already been made, fixing the slabs with dowels is strictly prohibited. A leak will inevitably appear at the location where the dowel is installed, which will lead to flooding of the basement and accelerated destruction of the foundation itself.

In this case, special fasteners can be used, which are a spike with teeth for fixation in the material and a flat platform with an adhesive layer.

Together with similar fasteners, gluing is done using adhesive foam for polystyrene foam or to a special adhesive mastic that does not contain solvents. If necessary, the seams are sealed with mounting or adhesive foam.

The layout of EPS slabs during the construction of USHP is carried out as follows. We lay the first layer on the prepared base - a compacted sand cushion - with the seams staggered relative to the adjacent slabs. The side elements are “L” - blocks, which are two EPS slabs connected perpendicular to each other.

Typically, such elements are made by installing formwork, but it is possible to use ready-made elements that do not require the use of formwork. Such “L” blocks can be manufactured in a factory, or they can be assembled independently at the work site. For this purpose, a special corner fastener has been developed, which consists of corners and screws, and which are mounted at a distance of 300 mm from each other. All elements of corner fasteners are made of high-strength polyamide, which eliminates the formation of cold bridges.

Summarizing

In addition to increasing the energy efficiency of the foundation, EPS insulation increases its service life, because the waterproofing is reliably protected by durable material from various mechanical influences. Selecting an option permanent formwork made of extruded polystyrene foam, you can significantly speed up and simplify all work on the construction of the foundation, because there will be no need to assemble and further disassemble wooden formwork, which means the developer will save time and money.

Some effective construction technologies created recently. This is explained by the appearance on the market of new materials with better or unique characteristics. Some of these techniques can be reproduced by the average person with relatively little study of the relevant materials. In this article we will look at the insulation process with my own hands the foundation of a private residential building or other relatively small building.

Why you may need to insulate a foundation slab

Improving the insulation parameters of a building will simplify and make its operation cheaper. This fact alone is enough to think about carrying out the appropriate work. Energy resources, despite temporary market fluctuations, will always have high value. By reducing their consumption, you can count on significant savings.

It should also be noted that correct engineering calculation will help to move the dew point beyond the contour of the main part of the building. This means that moisture will not condense inside the structures. Thus, after modernization, the conditions for the appearance and development of mold will worsen, and hidden corrosion processes will stop.

Separately, it is necessary to consider soil heaving. It happens in winter period. These mechanical impacts can create great pressure on the structural elements of the building. High-quality insulation of the foundation slab will prevent such and other harmful effects listed above.

Any technology becomes clearer with examples that confirm the feasibility of its use. In this case, you should pay attention to the “insulated Swedish slab” foundation. Here are the main parameters of this foreign technique, which is increasingly used today in domestic private housing construction:

It is a single structure made of cast concrete with reinforcement and stiffeners. It is installed on a cushion and surrounded by polystyrene foam boards.
Sand is initially poured under the main insulation and on the sides of it.
A system for collecting water and discharging it into drainage is pre-installed.
The blind area along the contour reduces the load on the drainage complex.
Comfortable temperature conditions are ensured using the “warm floor” system. It is built into the foundation at the stage of its creation.

This name itself determines the country of origin of the technology. In Sweden it has been successfully used for more than half a century, and in Russia private individuals and construction companies They have been using similar techniques for about ten years. Such time frames are quite sufficient for valid conclusions. Practical tests confirmed the presence of the following features:

This foundation construction technology is well suited for the construction of 1-2 storey buildings. For more tall buildings must be ordered individual project. It will then have to be agreed upon by all official authorities.
To completely eliminate the possibility of flooding of the building during floods, sand bedding of the required height should be installed. To determine it, you can use statistical data for the desired region with maximum levels. If necessary, additional measures are taken to improve the drainage and waterproofing system.
On sandy soils you can save money during the construction process. There is no need for a productive water drainage system here.
Working with concrete, as in all other similar cases, is recommended only in warm period. It is possible to fill the foundation in winter, but this will be accompanied by increased costs and will increase the risk of defects.
This design works especially well in combination with a “warm floor”. In particular, when the heating is turned off, even in the cold season, heat will remain in the house for 72 hours.
A professional company can complete a full cycle of work in 3-4 weeks.

Material for creating a high-quality insulating layer

You can make a choice based on analogues of materials that are used in Swedish technology. But first, let’s rule out unsuitable options:

Mineral wool different types do not have the necessary rigidity, strength and absorb water too well.
Expanded clay, other granular materials. They are also not suitable, since they cannot become a dense, moisture-proof base for the future foundation.
Polymer foam materials that are created directly on work sites. Some of them can be applied. But the implementation of such a project will require certain skills. You will also need special equipment.

Using the method of elimination, we found the “winner” of this correspondence competition. This is factory-produced foam polystyrene, penoplex. We list below those characteristics of the material that will be useful for solving the tasks:

Its production method involves the production of standardized products. Thus, if you purchase penoplex from a well-known brand, you can be sure that each slab will have the same parameters.
Precise dimensions and low weight will facilitate transportation, storage, and installation operations.
The uniform distribution of closed bubbles in the penoplex structure provides excellent thermal insulation properties. To fully insulate a monolithic foundation, you do not need to create a layer that is too thick.
This material is durable and does not allow moisture to pass through. Many types of slabs are made from it with special grooves along the edges, which makes it possible to ensure the tightness of butt joints without additional means.

Insulation of slab foundations

We have found out the main parameters of this technique, so we can proceed to the description of the working operations. Let's look at the steps that are used to insulate a foundation slab:

For this group of works, it will be enough to create a layer of high-quality penoplex with a thickness of no more than 10 cm. It can be formed from two rows of slabs, which are laid in a checkerboard pattern with joint overlapping of the joint areas.
Site preparation should be carried out taking into account the geology of the site and soil characteristics. When creating a recess, the bottom must be made level, so it is recommended to use manual labor in the final stages.
Sand is backfilled and compacted, after which temporary formwork is installed, and the first layer of concrete is poured without reinforcing elements.
When the base has hardened, foam boards are laid on it in the order indicated above. They are covered with a thick top plastic film. The seams between the individual strips are carefully sealed with wide tape.
Next, the main foundation is created from reinforced concrete.
After it hardens, foam boards are attached to the end parts with an adhesive composition.

Choice of insulation

External insulation technology

Internal insulation technology

Insulation of the foundation slab body

Insulation methods

Advantages of timely insulation

What materials can be used to insulate a slab foundation?

Why do experts recommend using penoplex for insulation?

Rules for insulating slab foundation structures

Carrying out insulation measures during the construction process

Insulation of basement external walls

Insulation of basement internal walls

New methods of foundation insulation

Thermal panels

Polyurethane foam

Blocks with insulation inserts

Insulation of slab foundations

Insulation of the basement floor from the inside

What does foundation insulation provide?

What insulation should I use for the foundation?

Polyurethane foam

Extruded polystyrene foam

Extruded polystyrene foam with grooves

Foundation insulation with polystyrene foam

Insulation of the foundation with polyurethane foam

Choice of insulation

External insulation technology

Internal insulation technology

Insulation of the foundation slab body

Scope and types

Construction technology of insulated slab

Preparing the base

Concrete preparation

Waterproofing

Insulation

Reinforcement

Pouring the foundation slab with concrete

Curing

When to remove formwork

Differences between an insulated monolithic Swedish slab and a video about its construction

Types of material

Harmful or harmless

Advantages, cost, technical characteristics

The main stages of the process of insulating the foundation with polystyrene foam yourself

Insulation of slab foundations

Insulation methods

Advantages of timely insulation

What materials can be used to insulate a slab foundation?

Rules for insulating slab foundation structures

Carrying out insulation measures during the construction process

Insulation of the foundation with polystyrene foam: technology for insulating the foundation of a house from the outside

Insulation characteristics

Prices for popular types of insulation

Preparatory stage

Calculator for calculating the thickness of foundation insulation

Features of foundation insulation with extruded polystyrene foam

Master class on working with EPS when insulating various types of foundations.