Insulation of the foundation slab. Slab foundation insulation technology

So that any building long time did not need repair - you need to worry about creating the most reliable foundation. This applies not only to the construction of the foundation, but also to its further insulation.

Thermal insulation is especially necessary in cold regions (where temperatures drop well below freezing for a long time). This primarily applies to concrete foundations: tape and slab.

Do I need to insulate, and why?

NS Before considering ways of working and choosing which technology is better, you need to figure out why you need thermal insulation of the base, and whether you need it at all.The technologies discussed below are equally relevant as for those who learn how to insulate the foundation wooden house, and for buildings made of concrete, brick, blocks.

Warming the foundation solves several problems at once:

Protects concrete from direct contact with moisture. It destroys the structure itself, and in addition leads to dampness in the basement (if any).

Protects the base from soil heaving.

Prevents freezing monolithic slab(or strip foundation).

The soil surrounding the foundation contains a certain amount of moisture. V different regions and in different areas it will differ, but there is always water in the ground. And upon contact with concrete, it will accelerate its destruction. The moisture contained in the pores of the concrete freezes and turns into ice. Ice takes up a larger volume than water, that is, it expands. Over time, this leads to the appearance and growth of cracks.

Another problem that the foundation insulation solves is soil swelling. It occurs when the weather changes seasonally: in subzero temperatures, the soil rises, after which (with warming) it sinks back.

This negatively affects the condition of the monolithic slab, since constant pressure is exerted on the concrete. This is especially dangerous if, when pouring the foundation, the work technology was violated (which often happens). In this case, the insulation of the foundation allows you to create a kind of protective layer that will take on the soil pressure.

The most serious reason why it is required to insulate the foundation from the outside is its freezing in winter. In frost, the soil freezes, taking heat from the stove. As a result, the floors in the premises of the first floor become cold, and it becomes cold and damp in the basement (if there is one in a private house).

For the reasons mentioned above, we can firmly say whether it is necessary to insulate the foundation, and why. For capital buildings, which must stand for more than 10 years, thermal insulation is definitely necessary.

Basic requirements for materials

Have heating of the foundation may not be carried out by any material.The main criteria are :

durability: work on thermal insulation requires digging a trench around the entire perimeter of a private house, and doing this every few years is difficult and expensive);

water resistance: even with protective structure(which covers the insulation from the ground) moisture can penetrate the heat insulator, which will worsen its effectiveness.

List of methods and general stages of work

Have heat the foundation of the house outsidecan be done in several ways :

Plate materials (polystyrene, expanded polystyrene, mineral wool boards).

Bulk materials (expanded clay).

The work can be carried out both at the stage of construction of a private house, and for an already finished building... The second option is better than the first: after construction, the foundation should stand for some time (about six months or a year, ideally, if it comes about a two- or three-storey residential cottage) in order to finally get its shape. However, during construction very often the deadlines are "burning", and therefore the minimum periods of exposure are observed, after which work on the construction of the walls begins immediately.

Regardless of how exactly the foundation will be insulated, there are general rules and stages:

Ideally, a primer should be applied around the entire perimeter. It is both cheap and time-consuming, and at the same time will create additional protection for concrete from moisture.

Work (regardless of which technology is used) is easiest to carry out in warm time of the year. The weather these days should be dry, since you will have to work in a trench, and the soggy earth will significantly complicate the task.

Application of panel materials

The most common option is to use board materials... These include:

Warming the foundation with expanded polystyrene (or mineral wool) is the most popular option among those who want to cope with the task on their own. The work can be done in two ways:

On self-tapping screws. Insulation sheet is attached to the surface of the slab. About 6-10 self-tapping screws are used per 1 m².

On the glue. Plates are glued to the surface with a special solution.

The general rules of work are as follows:

The insulation starts to be attached from any lower corner, horizontally (that is, the next sheet is attached from the side, and not from above).

Each next row is mounted with a shift: so that the seams between the heaters do not create a solid line).

Seams are glued with waterproofing tape (or construction tape).

Warming the base with expanded polystyrene (video)

Application of sprayed insulation

TO this option includes the use of polyurethane foam. The technology has a significant drawback: do-it-yourself insulation of the foundation is difficult to implement: for spraying, special expensive equipment is required. Its purchase is unprofitable if only 1 cottage is planned to be insulated, even with all the additional outbuildings.

For acquaintance - let's figure out how to insulate the foundation of a house outside in this way:

At the place of work, the insulation itself is prepared (obtained by mixing two components T ov in a sealed container).

From a special installation, polyurethane foam is sprayed onto the surface, where it instantly solidifies, turning into dense foam.

Of the clear advantages of this method:

saving time (for 1 work shift, 1-2 workers can cover more than one hundred "squares", while fixing the foam can take more than 1 day);

does not require leveling the surface;

creates a continuous layer (without seams, as between foam sheets);

polyurethane foam is the "warmest" insulator (thermal conductivity - about 0.03 W / mK).

Warming the base with polyurethane foam (video)

Application of bulk materials

Have Do-it-yourself heating of the foundation is easiest to do with the help of a bulk insulator - expanded clay.

The trench for such work will require a wider one. Expanded clay, as a heater, does not hold back cold well, and therefore a layer of 5-10 cm (as with the materials above) will no longer be enough. The recommended width of the expanded clay layer is 40-80 cm.

Consider how to properly insulate foundation in this way:

The bottom of the trench dug around the perimeter is covered with a waterproofing film (or geotextile, oryou can use ordinary dense polyethylene, ideally in several layers).

About 10-20 cm of crushed stone is poured to the bottom.

Is laid in rubble drainage pipe (to remove moisture that may get into the expanded clay layer.

The trench is backfilled with expanded clay.

Ideally, it is recommended to make a partition of brick, plastic or metal panels or from slate,and fill in expanded clay between the partition and the foundation. In this case, it will act as a barrier, preventing moisture from getting inside (on expanded clay).

Installation of insulation protection

After the insulator is fixed on the surface, it is recommended to complete the insulation of the foundation with your own hands with a protective structure device. As for expanded clay, it has already been mentioned above.

For polyurethane foam or sheet materials the work is performed as follows:

Wooden or metal carcass- lathing. It is attached to the foundation, and the insulation is installed (sprayed) between the frame.

On top of the frame, on self-tapping screws, attached protective layer... It can be slate, plastic or metal (if metal is necessarily galvanized or stainless) panels or sheets.

Alternatively, you can build a brick partition in front of the insulation (as mentioned above).

Some effective construction technologies created recently. This is due to the appearance on the market of new materials with better or unique characteristics. Some of these techniques can be replicated by the average person after relatively little study of the relevant material. In this article, we will consider the process of warming with my own hands the foundation of a private residential building, another, relatively small structure.

Why you may need to insulate the foundation slab

Improving the insulation parameters of a building will make it easier and cheaper to operate. This fact alone is enough to think about carrying out the relevant work. Energy resources, despite temporary market fluctuations, will always have a high value. By reducing their consumption, it will be possible to count on significant savings in money.

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

Separately, it is necessary to consider the heaving of soils. It takes place in winter period... These mechanical influences are capable of creating 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 by examples that confirm the feasibility of its application. In this case, you should pay attention to the “insulated Swedish plate” 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 stiffening ribs. It is installed on a pillow and surrounded by expanded polystyrene boards.
• Sand is initially poured under the main insulation and on the sides of it.
• A system for collecting water and discharging it into the drainage is pre-installed.
• The blind area along the contour reduces the load on the drainage complex.
• Providing comfortable temperature conditions is carried out using the "warm floor" system. It is built into the foundation at the stage of its creation.

This name itself defines the country of origin of the technology. In Sweden, it has been successfully used for more than half a century, and in Russia, individuals and construction companies have been using similar techniques for about ten years. Such timeframes are quite sufficient for well-grounded conclusions. Practical tests have confirmed the following features:

• This foundation erection technology is well suited for construction 1-2 storey houses... For taller buildings it is necessary to order individual project... It will then have to be agreed upon in all official instances.
• In order to completely exclude the possibility of flooding the structure during floods, a sand bed of the required height should be installed. To determine it, you can use statistical data for the desired region with maximum levels... If necessary - apply additional measures to improve the drainage system and waterproofing.
• On sandy soils, you can save money during the construction process. There is no need for a productive drainage system.
• Working with concrete, as in all other similar cases, is recommended only during a warm period. It is possible to fill the foundation in winter, but this will be accompanied by increased costs and increase the risk of marriage.
• This design works especially well in combination with a "warm floor". In particular, if the heating is turned off, even in the cold season, the heat will remain in the house for 72 hours.
• A professional company is able to 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 analogs of materials that are used in Swedish technology. But first, let's exclude unsuitable options:

• Mineral wool different types do not have the necessary rigidity, strength and absorb water too well.
• Expanded clay, other materials from granules. They are also not suitable, since they cannot become a dense, moisture-proof base for the future foundation.
• Polymeric foam materials that are created directly at 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.

By the method of elimination, we have found the "winner" of this correspondence competition. This is factory-made foamy polystyrene, penoplex. Let us list further those characteristics of the material that will be useful for solving the assigned tasks:

• Its mode of production involves the release of standardized products. Thus, if you buy penoplex famous brand, then there will be no doubt that each plate will have the same parameters.
• Exact dimensions and low weight will facilitate transportation, storage, assembly operations.
• Uniform distribution of closed bubbles in the structure of the foam provides excellent thermal insulation properties... To make a complete insulation 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 from it are produced with special grooves along the edges, which allows without additional funds ensure the tightness of butt joints.

Insulation of the slab foundation

We have found out the main parameters of this technique, so you can proceed to the description of the working operations. Consider the steps that are used to insulate the foundation slab:

• For this group of works, it will be quite enough to create a layer of high-quality polystyrene foam with a thickness of no more than 10 cm. It can be formed from two rows of slabs, which are stacked 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, soil characteristics. When creating a depression, the bottom must be made even, therefore, manual labor is recommended in the final stages.
• The sand is backfilled and compacted, after which a temporary formwork is installed, the first layer of concrete is poured without reinforcing elements.
• When the base has hardened, penoplex plates are laid on it in the order indicated above. They are covered on top with a thick plastic wrap. The seams between the individual strips are carefully sealed with wide tape.
• Next, the main foundation is created from reinforced concrete.
• After it hardens, penoplex plates are attached to the end parts with an adhesive composition.

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... Warming foundation slab will help to significantly reduce heat loss through the base and reduce the effect of frost heaving of the soil. The structure, when the soil moves, rises and falls along with the foundation, which protects the structure of the house from the formation of cracks.

general information

Design slab base consists of layers:

• the geotextile is covered with overlapping strips on the sand layer, the joints are glued with tape;
• crushed stone is poured in a layer of 15-20 cm;
• fill in the leveling layer cement mortar, 5-10 cm thick;
• be sure to isolate the structure from moisture using roll or coating materials;
• arrange a heat-saving layer;
• obscure plastic wrap overlapping stripes by 20 cm;
• lay the reinforcing mesh;
• poured with concrete.

Installation and insulation of a slab monolithic foundation is expensive due to high consumption building materials... When the soil freezes to a great depth and a significant deepening of the strip foundation is required, the device of the slab will be cheaper, and less land 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 will further reduce 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 whole house along with it move simultaneously with the soil;
• the slab can be mounted on any type of soil, even on peatlands and swampy areas;
• the slab is erected above the level of soil freezing, thanks to sand pillow frosty heaving practically does not affect the structure;
• reinforced concrete slab is not subject to shrinkage;
• suitable for the construction of buildings up to 3 floors.

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

Advantages of slab thermal insulation

As thermal insulation material use polystyrene foam, polystyrene foam, polyurethane foam. Mineral wool not suitable due to its low strength and high degree moisture absorption.

There is a technology for mounting a Swedish plate. The main difference is that concrete structure erected on a layer of heat-saving material, thanks to this, the soil under the house does not freeze and does not heave.

The main advantages of the Swedish plate are:

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

Around the buildings provide drainage system consisting of pipes for drainage of rain and melt water.

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

Disadvantages of slab foundation

The slab foundation is not always the best option... You always need to do everything in advance. necessary calculations and select the most suitable type grounds for the home.

Disadvantages of the stove:

• not suitable for construction on areas with a slope;
• to build a house with a basement on a slab, you need to deepen to a great depth, this will be very expensive;
• it is difficult to repair communications under the foundation slab;
• during construction in winter it will be required additional expenses for heating concrete and maintaining the desired temperature on the site.

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

Insulation materials

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

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

Insulated plate installation

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

Insulation of the slab foundation allows you to save significant money on heating the room during operation.

Site preparation

At the stage of creating the project, it must be borne in mind that the site for the foundation slab must be wider than the house building by at least 1 m on each side.

Instructions for performing preparatory work:

1. They clean the construction site from debris, the root system of trees and shrubs.
2. Mark the position of the slab according to the project.
3. They clean and remove the fertile soil layer. The extent to which the slab is buried depends on the geological and climatic conditions. Most often, the thickness of the slab varies from 20 to 30 cm, less often the base is deepened by 50 cm.
4. They dig a pit, manually level its bottom and side walls.
5. Pipes are installed around the perimeter to drain rain and melt water.
6. Spread the geotextile in overlapping strips. The material should cover the bottom and extend onto the walls along its entire height.
7. Wooden stakes or metal rods are driven in. Pull the cord strictly horizontally. It will serve as a guide for uniform filling of sand and gravel.
8. Sand is poured, 20-30 cm thick. Sand is evenly distributed over the entire area, moistened with water and compacted well.
9. Spread out geotextiles.
10. Crushed stone is poured, evenly distributed around the perimeter, carefully tamped.
11. They carry out all the necessary communications. They dig trenches for them in the rubble a little wider than the cross-section of the pipes. The pipeline is laid, a layer of sand is poured on top.
12. The sandy surface is leveled.

If the pipeline is laid prior to the compaction stage, the pipes may crack.

Insulation of the slab

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

1. Mount removable formwork from the boards, props are installed so that the structure does not fall apart under the weight of the concrete.
2. Pour a layer of concrete 50 mm thick.
3. After the cement mortar has completely solidified, sheets of foam are laid on it end-to-end and glued. Adhesive composition applied in dots along the perimeter of the sheet and in the center. A layer thickness of 10-20 cm is enough. The joints of the row are placed in a checkerboard pattern, with an offset of 1/3. When laying in two rows, the joints must not overlap.
4. Spread the dense polyethylene in overlapping strips. The joints are sealed with tape.
5. Lay down reinforcement cage, the formwork is poured with concrete.

After the slab has dried, the formwork is disassembled, the side walls are insulated with the same material that was used for laying under the slab.

The insulated base / plinth contributes to the increase of heat saving inside the building.

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

Heating pipes installation rules

Heating pipes are used during the installation of the USHP. There are such rules for laying them:

• Tighter pipe laying allows for more high temperatures heating the room.
• The distance between external walls and pipes must not exceed 150 mm. Closer to the center, the paving pitch can be increased up 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 joints of monolithic plates. In this case, it is better to draw two contours. The pipeline crossing the joint is insulated with steel sleeves 30 cm long.

You can watch the video how to make an insulated Swedish stove with your own hands:

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

Insulation is an important part of any construction. All external parts of the building must be insulated from heat loss: walls, roof, basement and foundation. Insulation of the basement of the building not only limits heat loss, but also prevents frosty heaving of the soil. How is the insulation of a monolithic foundation carried out? And what are the features of installing insulation on the wall and floor

Insulation of foundations

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

Various foundation designs have different ways insulation. Deep tape - only vertical walls near the ground are insulated, shallow tape - walls and soles. Pile foundation rests on frost-free soil, therefore only lateral surfaces piles.

Insulation of a monolithic foundation slab is performed from the sides and bottom. This is necessary due to the location of the slab in the zone of soil freezing. A monolithic slab foundation is a shallow structure. Its depth rarely exceeds 50 cm. Therefore, the entire slab is located in the zone of freezing soil and requires high-quality insulation. What materials are used to insulate the foundation slab?

Foundation insulation material: Penoplex

Increased requirements for moisture and water resistance are imposed on the foundation insulation. It comes into contact with moist soil, therefore, in addition to insulation, it must prevent moisture from penetrating into the walls of the house. In addition, the foundation insulation must withstand compressive loads.

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

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

How to insulate: inside or outside?

How to properly insulate the foundation with penoplex - from the outside or from the inside? Theoretical calculations show that the location of the insulation with outside protects the wall and slab from freezing. The location of the insulation inside the wall does not protect the wall and the slab, but it makes it possible to improve the microclimate in the room. This means that outdoor insulation is the most the best way for all building surfaces.

However, it is not always possible to carry out insulation from the outside. So for the foundation, external insulation is possible only at the construction stage. After that, the base can be insulated from heat loss only from the inside.

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

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

Penoplex insulation during the construction phase

Thermal insulation during the construction phase involves laying the insulation on the ground before pouring the concrete. We list the sequence of actions for insulation during construction:

• To eliminate uneven pressure of the foundation on the ground, part of the soil is removed and gravel and then sand backfill is made. A layer of sand is spilled with water and carefully tamped.
• After that, a layer of waterproofing and insulation plates are laid.
• Reinforcement rods are placed on top of the insulating material and concrete is poured. In this case, the reinforcement rods are placed in two rows, the lower row is supported by plastic beacons (so that after pouring the reinforcement is inside the concrete).

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

Swedish foundation

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

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

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

Advantages of an insulated foundation

We list the advantages that make the basement slab insulation essential element construction:

• Saving concrete, reducing construction costs.
• Acceleration of the construction of a house.
• Reduction of heat loss and reduction of utility bills.
• Improving the indoor climate.
• Increase the durability of the foundation slab and the entire structure.

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

Insulation of the foundation slab updated: February 26, 2018 by: zoomfund