Insulation of slab foundations. Insulation of the foundation slab Slab foundation with insulation

The slab base can withstand significant external influences and is suitable for construction in areas with complex, unstable soils prone to frost heaving, with high level groundwater. Insulating the foundation slab will help to significantly reduce heat loss through the base and reduce the impact of frost heaving of the soil. When the soil moves, the building rises and falls along with the foundation, which protects the house structure from the formation of cracks.

general information

The design of the slab base consists of layers:

on sand layer cover the geotextile with overlapping strips, seal the joints with tape;
pour crushed stone in a layer of 15-20 cm;
pour a leveling layer of cement mortar, 5-10 cm thick;
be sure to isolate the structure from moisture using rolled or coating materials;
arrange a heat-saving layer;
cover with plastic film in stripes overlapping by 20 cm;
lay the reinforcing mesh;
poured with concrete.

Installation and insulation of a slab monolithic foundation is expensive due to the high consumption of building materials. When the soil freezes to a great depth and a significant deepening of the strip foundation is required, installing a slab will be cheaper and less excavation work will be required.

Advantages of a slab foundation

The slab base has the following advantages:

the concrete slab serves as the floor of the first floor, which further reduces the cost of its installation;
is an excellent option for the foundation of a house, the construction of which is carried out on floating soils; the slab and the entire house along with it move simultaneously with the soil;
the slab can be mounted on any type of soil, even on peat bogs and marshy areas;
the slab is erected above the soil freezing level, thanks to the sand cushion, frost heaving has virtually no effect on the structure;
reinforced concrete slab is not subject to shrinkage;
suitable for the construction of buildings up to 3 floors.

Insulating the foundation slab reliably protects it from deformation during seasonal soil heaving and extends the life of the structure.

Advantages of slab insulation

As thermal insulation material Expanded polystyrene, polystyrene foam, and polyurethane foam are used. Mineral wool is not suitable due to its low strength and high degree of moisture absorption.

There is a technology for installing a Swedish stove. The main difference is that concrete structure It is built on a layer of heat-saving material, thanks to which the soil under the house does not freeze or heave.

The main advantages of the Swedish stove are:

the construction of the foundation and the laying of communications are carried out in one technological cycle;
the heat-saving layer allows you to increase the efficiency of the heated floor;
installation of the foundation is carried out without the involvement of a large amount of construction equipment.

A drainage system consisting of pipes for draining rain and melt water is provided around the building.

The design of the slab helps to transfer all the loads from the building to the layer of heat-saving material, therefore increased demands are placed on the materials used.

Disadvantages of a slab foundation

Slab foundation is not always the best option. Always do everything in advance necessary calculations and select the most suitable type of foundation for your home.

Disadvantages of the stove:

not suitable for construction on sloped areas;
to build a house with a basement on a slab, you need to dig it to a great depth, this will be very expensive;
it is difficult to repair communications carried out under the foundation slab;
During construction in winter, additional costs will be required for heating the concrete and maintaining the required temperature on the site.

A slab foundation is erected only when it is impossible to install a strip foundation.

Insulation materials

The table shows the materials used to insulate the foundation slab and their characteristics:

№	Thermal insulation material	Characteristics
1	Styrofoam	Consists of cells filled with air. Available in the form of sheets, it has insufficient density, so its surface needs additional protection.
2	Extruded polystyrene foam	Able to withstand significant compressive loads without changing its size and structure. It is produced in the form of rectangular sheets with small cells filled with air. Lay the sheets in 1 or 2 layers. The second layer must be laid out so that the seams of the sheets of the first and second row do not intersect. During installation, provide holes for moisture drainage.
3	Polyurethane foam	It is a type of foamed plastic with many pores filled with air bubbles. The composition is prepared directly at the construction site. The two components are mixed, resulting in a dense, solid foam that is applied to the surface. The slab insulated with polyurethane foam has high thermal and sound insulation properties and can withstand moisture. Refers to low-flammable materials, and some brands are difficult to burn.

Most often, extruded polystyrene foam is used as insulation under the foundation slab.

Installation of insulated slab

The construction of a monolithic slab foundation requires performing all calculations taking into account geological, climatic conditions and the mass of the building.

Insulating a slab foundation allows you to save significant money on heating the room during operation.

Site preparation

At the creation stage of the project, it is necessary to take into account that the area for the foundation slab must be wider than the house building by at least 1 m on each side.

Instructions for performing preparatory work:

The site where construction is taking place is cleared of debris and the root system of trees and shrubs.
Mark the position of the slab according to the design.
Cleaned up and taken away fertile layer soil. The degree of slab burial depends on geological and climatic conditions. Most often, the thickness of the slab varies from 20 to 30 cm, less often the base is buried by 50 cm.
They dig a pit and manually level its bottom and side walls.
Pipes are installed around the perimeter to drain rain and melt water.
Geotextiles are laid out in overlapping strips. The material should cover the bottom and extend to the entire height of the walls.
Drive in wooden stakes or metal rods. Pull the cord strictly according to horizontal level. It will serve as a guide for uniform filling of sand and crushed stone.
Pour sand 20-30 cm thick. Distribute the sand evenly over the entire area, moisten it with water and compact it well.
Lay out geotextiles.
Pour crushed stone, distribute it evenly around the perimeter, and compact it thoroughly.
Conduct all necessary communications. They dig trenches under them in the rubble a little wider than the cross-section of the pipes. The pipeline is laid and a layer of sand is poured on top.
The sandy surface is leveled.

If the pipeline is laid before the crushed stone compaction stage, the pipes may crack.

Insulation of the slab

Step-by-step instructions for insulating a monolithic foundation slab:

They install removable formwork from boards and install supports so that the structure does not fall apart under the weight of concrete.
A layer of concrete 50 mm thick is poured.
After the cement mortar has completely hardened, sheets of penoplex are laid on it close to each other and glued. Adhesive composition applied in dots around the perimeter of the sheet and in the center. A layer thickness of 10-20 cm is sufficient. The joints of the row are placed in a checkerboard pattern, offset by 1/3. When laying in two rows, the joints should not intersect.
Spread thick polyethylene in overlapping strips. The joints are sealed with tape.
Stacked reinforcement cage, fill the formwork with concrete.

After the slab has dried, the formwork is dismantled, the side walls are thermally insulated with the same material that was used to lay it under the slab.

The insulated base helps to increase heat saving indoors.

When installing insulation on bitumen insulation, you need to wait until it dries completely. If laid on a damp layer, the materials may be damaged and the effect of thermal insulation and waterproofing will be reduced.

Rules for installing heating pipes

When installing USHP, heating pipes are used. There are the following rules for their installation:

More dense pipe laying allows for higher room heating temperatures.
The distance between external walls and pipes should not exceed 150 mm. Closer to the center, the laying step can be increased to 250 mm.
To minimize hydraulic losses, the length of one loop should not exceed 100 m.
Do not lay pipes closer than 100 mm from each other.

Heating pipes must not be installed at the junction of monolithic slabs. In this case, it is better to lay two circuits. The pipeline crossing the joint is insulated with steel sleeves 30 cm long.

How to make an insulated Swedish stove with your own hands can be seen in the video:

An insulated foundation slab allows you to reduce heating costs during operation and helps reduce the level of frost heaving in the soil. Thanks to this, the life of the foundation is extended, and living in the house becomes more comfortable.

The monolithic slab foundation has proven itself well when used in weak and heaving soils. Annual soil freezing in winter period leads to uneven rise and settlement of the slab base, which contributes to the occurrence of mechanical deformations that can cause destruction of the slab itself and the building built on it.

A layer of horizontal insulation can reliably isolate the foundation slab from the zone of frost heaving, contact with soil moisture and prevent freezing.

Advantages of insulating a slab base

Horizontal slab insulation

High-quality insulation of a monolithic foundation slab guarantees the durability of the building and long-term operation without the need for unplanned repair work. Particularly relevant is the insulation of the foundation slab under residential buildings, when it is possible to avoid significant heat loss on the first floors of the house.

Insulation of the foundation slab must be performed for the following reasons:

Providing increased waterproofing of the foundation.
Significant reduction in heat loss.
Saving money on heating a residential building, real mode heat saving.
Preventing the formation of condensation that can destroy the building structures.
Improving living comfort.
Temperature stabilization interior spaces exploited residential building.

Materials for insulating a monolithic slab foundation

The choice of materials for insulating a slab base depends on a number of certain conditions, first of all, on the possibility of using special equipment (polyurethane insulation must be performed using a special polyurethane foam installation for spraying insulation), and the availability of sufficient free funds to purchase insulating materials.

Typically, insulation of foundation structures is carried out using the following materials:

One of the best insulation materials- Styrofoam

Polyurethane foam is a type of foamed plastic that is riddled with pores containing air bubbles. The composition for polyurethane foam insulation is made directly on the construction site, for which two compositions are mixed, which, as a result of a chemical reaction, form a durable hardened foam. Different ratios when mixing the starting materials make it possible to obtain insulating compositions with different qualities, suitable for insulating foundations made of different materials (including reinforced concrete). PPU has unique qualities: helps maintain heat in the room; reduces noise; improves sound insulation; does not decompose under the influence of excessive moisture; Resistant to a number of chemical liquids. The material is highly resistant to ignition (some brands of polyurethane foam are not flammable and belong to the group of low-combustible materials).
Foam plastic - the structure of the material consists of a foamed substance containing pores filled with air. Polystyrene foam is used for insulation building structures, including foundations, but the surface of such insulation requires additional surface protection due to the low mechanical strength of the material.
Extruded polystyrene foam - produced in the form of rectangular sheets with a fine-cell structure. The material has unique properties– the ability to withstand high compressive loads without changing geometric dimensions and internal structure. Extruded polystyrene foam is widely used to insulate foundation slabs without additional protection. When using material to insulate foundation slabs, it is very important to provide special openings for the free exit of soil moisture.

Foundation slab insulation technology

When insulating a foundation slab, horizontal and vertical insulation is used, in which a layer of insulation is laid under the slab base or along the side walls of the foundation structure. Expanded polystyrene or polystyrene foam is most often used as an insulating material. Watch the video on how to insulate a foundation slab with polystyrene foam.

The insulation is laid during the installation of the foundation using the following insulation technology (consider the option of insulating the foundation with polystyrene foam):

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 sand layer, for which temporary formwork is installed.
After the concrete screed has hardened, insulation is laid out from polystyrene foam boards, making sure that the mounting grooves coincide 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 erected for pouring a slab base, into which a spatial frame made of reinforcement with a diameter of 10 mm is mounted. 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.

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

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 vertical surfaces 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 money 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 bills public utilities, 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 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 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 last years When insulating slab foundation structures, developers use extruded polystyrene foam, since it does not require additional protection and can perform its functions 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 ideal option for any construction projects.

External insulation of the foundation with expanded polystyrene or penoplex is possible only on initial stages 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 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.
Are being laid engineering Communication, for example, water and sewer pipes. 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 works.
On 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.

Foundation insulation reduces the need for high power heating system and avoids moisture condensation, which often occurs as a result of the temperature difference between the inside of the plinth and the soil around the base.

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 The strip foundation plinth 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 a foundation is to insulate it from the outside. Carefully designed perimeter drainage system consisting of washed gravel, perforated plastic pipe and a fabric filter. Highly recommended for areas with poor soil drainage.

Some insulating foams are made with boric acid to prevent 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 a finished building. This insulation has the following advantages and disadvantages:

Advantages:

This is much cheaper than insulating external walls for existing buildings.
There is a wider choice of materials as 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 wood or metal formwork, is a system of 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.

This material is applied by spraying. 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.

Research and computer models showed that an 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

Isolation basement depends on whether there is ventilation in it. 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, insulation is laid out from polystyrene foam boards, making sure that the mounting grooves coincide 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 erected for pouring a slab base, into which a spatial frame made of reinforcement with a diameter of 10 mm is mounted. 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 very coldy. 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 ground floor 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 important part of the work when insulation of a fresh foundation slab is required is the selection 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. Most the best option– these are 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 whole line 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 assistance 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 service life;
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.

Most effective method insulating the foundation with this material means using it in zones of soil freezing. The insulation is installed to the freezing depth. This is quite enough. Special attention when insulating, it is worth paying attention 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 a 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

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 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.

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, 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.

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 along the surface and edges of the slab. The second method is more economical and reliable. With help gas burner pieces of paraffin melt. 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 on glue or on 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 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;
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

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. The thickness of the insulating material will be less, 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 one that 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

When planning, 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.
. 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.

Why do experts recommend using penoplex for insulation?

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.

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 enough 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 of the material are created from naturally occurring gas. 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. The finished mixture is 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 cooking disposable tableware, 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 is a 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. High density expanded polystyrene provides 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

For self-insulation Foundation polystyrene foam will require 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 top part plate 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 ground part- then she gets off 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 wetter soil, a larger thickness of polystyrene foam will be required, which is also selected depending on the 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 is not the cheapest, it is 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 after installation it must be covered with external finishing - 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. Dimensions standard plate expanded polystyrene – 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 important stages Installation of this type of foundation requires 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.

During construction of this type Extruded polystyrene foam (EPS) was used for the foundation. In master class format professional builders They will tell you how to choose and how to work correctly 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, but due to the presence large quantity small pores have 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 a material that can work in aggressive environmental conditions. 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 buildings." For different regions The thickness of the 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.

Choosing specifications thermal insulation, we are guided by the following principles:

When thermally insulating a strip foundation, when only insulation is vertical wall, increased strength of the material is not required, because in this case, the EPS absorbs loads only from the ground backfill. Therefore for shallow foundations suitable brands of extruded polystyrene foam with a compressive strength (at 10% linear deformation) of 150-250 kPa.
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 cushion). 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 various ways fixation of extruded polystyrene foam. If it is necessary to insulate the vertical part of the foundation on which it has already been made waterproofing layer, 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. By choosing the option of permanent formwork made from 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.

general information

Advantages of a slab foundation

Advantages of slab insulation

Disadvantages of a slab foundation

Insulation materials

Installation of insulated slab

Site preparation

Insulation of the slab

Rules for installing heating pipes

Advantages of insulating a slab base

Materials for insulating a monolithic slab foundation

Foundation slab insulation technology

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

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

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.

Read also