How and with what to insulate the foundation of a house from the outside: technologies, materials, tips. How and how to insulate the foundation from the outside: pile, columnar, strip Material for insulating the foundation of a house from the outside

Foundation insulation of a house under construction is an important stage of construction, contributing not only to the preservation of heat in the house, but also to protecting the foundation of the house from destruction.

The climate of the main part of the Russian regions is so harsh that the ground freezes to great depth. Since the volume of soil increases during freezing, its level also rises at the same time.

Particularly strong ground movements occur when constructing buildings in swampy areas where humidity is significantly increased. Such soil is called “heaving” because when it freezes, its level can rise by 30-35 centimeters.

Periodic changes in ground level become cause of deformation, and then the destruction of the foundation of the building. The only way to minimize the impact of soil freezing on the foundation is to insulate it.

Main works insulation of the foundation, especially if the foundation of the building is laid above the soil freezing level, should be carried out even when it is laid.

If the house construction project provides for a foundation in the form monolithic slab, which is subsequently used as the basis for the flooring of the basement, or the floor of the first floor, then its insulation must be performed. This will not only protect the foundation from deformation, but will also reduce heat loss.

Equally important to reduce heat loss insulation of the basement part of the foundation, performed from the outside.

Especially relevant such insulation when using the basement space as functional premises where a comfortable air temperature is necessary. Internal insulation of these premises is not recommended, since this does not relieve them from dampness.

Placing insulation on the outside of the foundation will solve many problems:

heat loss and heating costs will be reduced;
the effect of soil swelling during frost is almost completely eliminated;
with external insulation of the foundation, condensation does not form on the internal walls of the basement premises;
external insulation serves as protection for the waterproofing layer, increasing its service life;
increases the service life of the building base structure.

As mentioned above, any insulation of the foundation is best done at the stage of its construction. However, the insulation of its outer part, quite possible carry out after the construction of the building. This is usually done when insulation work was not carried out at all, or was done poorly.

It is more difficult to insulate the foundation from the outside of a finished house, and such work will cost more. However, its result will ensure warmth and comfort in the house.

Materials for insulating the foundation outside the house

To protect the outer part of the base buildings use a variety of materials that can limit exposure to low air temperatures, as well as avoid access to groundwater in the foundation. Such materials can be either natural (sand,) or artificial (,) origin.

Each of the materials selected for insulating the foundation must have the following properties:

high mechanical strength to withstand soil pressure loads;
minimum moisture absorption rates necessary to protect the foundation surface from access to melt and groundwater;
absence of harmful chemical impurities;
frost resistance;
ease of installation, making it possible to carry out insulation without the involvement of specialists.

When using any of the materials selected for external insulation of the base of the building, it is important strict adherence to technology work. Only the correct sequence of insulation will give the expected result - high-quality thermal insulation of the foundation.

Insulation of the foundation with sand or expanded clay

Using sand or expanded clay for insulating the base of a building is the most cost-effective way to perform thermal insulation yourself.

These materials simultaneously perform the role waterproofing and pressure compensator soil when it swells. Therefore, sand and expanded clay are often used on clayey and moist soils that have a high expansion coefficient when frozen.

The procedure for performing insulation with sand or expanded clay next:

A pit is prepared on the outside of the foundation, with a depth slightly lower than the foundation of the house. The width of the pit depends on local conditions (soil moisture and average temperature in winter), but not less than 80 cm.
Geotextiles are laid at the bottom of the pit, then a layer of crushed stone. A perforated pipe is mounted on top, leading into a drainage well. A layer of crushed stone follows again on top of the pipe.
After thoroughly cleaning and drying the foundation, the foundation is waterproofed. If the insulation is performed with expanded clay, then it is better to use rolled materials for waterproofing, since the coating insulation is easily damaged by this insulation.
The insulation process is completed by backfilling with insulating material. Sand or expanded clay is poured in layers, with each layer compacted.
The insulation ends with the installation of blind areas.

Important: Since expanded clay is capable of absorbing moisture from the soil, when insulating the foundation from the outside, it is recommended that before backfilling it, cover the trench with a thick polyethylene film so that its edges subsequently cover the expanded clay from above.

What is better for insulating mineral wool, penoplex or polystyrene foam?

Although mineral insulation(varieties) are distinguished by good thermal insulation; today they are rarely used for external insulation of the foundation. Too much additional work needs to be done to obtain insulation of proper quality.

For installation of mineral wool it is necessary to erect a frame and create its protection from getting wet. To protect the insulation from mechanical damage, an additional brick wall is usually erected. For these reasons, the use of mineral wool as insulation for foundations is almost a thing of the past.

Among the popular materials, with the help of which the foundation of a house is insulated from the outside, its analogues - polystyrene foam and - have become the most popular material.

These materials have similar characteristics and installation method, however, foam plastic has less strength and service life, and the ability to absorb moisture contributes to its rapid destruction.

Best qualities has penoplex, so it is currently the most popular material for external foundation insulation. In addition to durability and excellent technical characteristics, consumers are attracted by ease of installation and relatively low price.

Penoplex insulation is done in the following order:

Along the perimeter of the foundation, soil is removed to a depth depending on the location of the foundation. The surface is thoroughly cleaned of soil particles and, if necessary, leveled with cement-sand mortar.
After the leveling solution has completely dried, a waterproofing layer consisting of water-based bitumen or polymer mastic is applied twice to the surface of the foundation.
Penoplex slabs are mounted on the dried waterproofing. Installation is carried out by gluing with acrylic glue. The slabs have grooves, so no gaps are formed during installation.
If necessary, the joints are sealed with polyurethane foam. Sometimes additional fastening with plastic “umbrellas” is used in the upper part of the foam insulation layer.
After installing the slabs, a fiberglass mesh is attached over them, and then the surface is plastered. The part of the base that remains after filling the soil from the outside can be finished with decorative material.

Attention! If the bitumen mastic is thick, it cannot be diluted with either acetone or gasoline. The use of such solvents in contact with penoplex causes destruction of the insulation.

Swiftly gaining popularity Another modern material for insulation is polyurethane foam. When using it, there is no need for mounting fasteners, since it is sprayed onto the surface of the foundation. Its insulating properties are such that 50 mm of polyurethane foam replaces 120 mm of polystyrene foam.

When using it no need in additional waterproofing. Consumers consider the only drawback to be the inability to apply the insulation themselves, since this will require special equipment.

The choice of insulation depending on the type of foundation

For insulating strip foundations Almost any material that has heat-insulating properties is suitable.

Installation of insulation is carried out directly on the surface of the base, therefore, for this type of foundation, technology is used that is standard for each of the insulating materials.

For insulation of pile foundations Some preliminary operations need to be performed. Since this type of foundation consists of vertical supports covered with a concrete slab - a grillage. Most often, such a foundation does not require insulation, however, when using thermal insulation protection for the grillage, the heat transfer of the building is significantly reduced.

As an insulating material Typically, polystyrene foam is used, fixed to the surface of the grillage. All places where the grillage comes into contact with the walls of the building and piles are pre-protected with a waterproofing layer of bitumen mastic or roofing felt.

After insulating the grillage a finishing is carried out on its surface, which serves as additional protection for the heat-insulating layer. For stable behavior of the blind areas, polystyrene foam slabs are also laid directly under them to a depth of about 30 cm. This way the entire perimeter of the house is insulated.

Today there is a fairly wide selection of materials intended for external insulation of foundations. Each of them has its own characteristics, including advantages and disadvantages.

With a reasonable approach, you can choose the most suitable option for a specific case. Based on the desire of most consumers to insulate the foundation themselves, polystyrene foam is most often purchased, the installation of which can be done without the help of specialists.

Watch the video for a master class on insulating the foundation of a house from the outside with your own hands:

For a video tutorial on how to insulate a foundation with polystyrene foam from the outside, watch the video below:

In wooden houses, less effort and money is spent on insulating all structures than in other types of buildings, because wood has low thermal conductivity. But even in log houses there are elements that cannot be made of wood, and often they become conductors of cold entering the house. The greatest heat loss awaits the owner who did not provide for insulation of the foundation, which is in direct contact with the ground. And since most often the foundation is mounted from concrete slabs or a monolith with high thermal conductivity, the percentage of heat leakage through the base can reach 20%. Let's consider how to insulate the foundation and what materials should be used.

Video advice from a specialist on thermal insulation of a wooden house

When is it better to insulate the foundation of a wooden house?

The most optimal time for insulating the foundation is the beginning of construction, when the walls are not yet standing and the subfloors have not yet been laid. But, unfortunately, most often the problem begins to brew during the operation of the building. And the first signals are dampness and mold in the underground, damp basements, which in winter are covered with frost and frost on the side adjacent to the street. But even in this case, it is not too late to insulate the foundation of the house.

It is most convenient to insulate the foundation before erecting the box

Isolation of the foundation box from direct contact with the soil

When the foundation is built, there is a lot of empty space inside the foundation box. If you are not planning a basement (or placing it under part of the building), then the entire box should be covered with earth or expanded clay to the level of the future floor. It will become an additional layer between the soil and the floors. The land will be cheaper, especially since when digging a pit a lot of excess soil is formed, which the owner has to fill inside the foundation. True, this method is simple only at first glance. If you have to use imported soil, then for an embankment one meter high for a 10x10 box, the land consumption will be the volume of seven KAMAZ trucks. In addition, it is unlikely that the equipment will be able to pour the brought soil inside, and you will have to shovel the entire volume manually. And the main disadvantage of earth insulation is the poor quality of thermal insulation.

It is more profitable to backfill with expanded clay. They do not fill the entire box with it, but only 40 cm from the inner walls of the foundation. In this case, you will save the basement, and you can place communication junctions underground.

To create expanded clay insulation, it is necessary to install formwork along the inner perimeter of the walls. It will not be removable, so use any durable materials that, due to external characteristics, will not be used outside the building. Slate, cutting boards, etc. are suitable. Expanded clay is poured inside the finished formwork, and when creating a subfloor, it is covered with a waterproofing layer and mineral wool.

If the laid communications do not allow you to pour expanded clay inside the box, then you can insulate it from the outside by adding waterproofing protection in the form of a brick wall

This method of insulation better insulates the house from the cold than earth, but it should be used as an addition to the main work. The main condition for good thermal insulation of the foundation should be the protection of its walls from cold and moisture. It is performed by gluing or spraying insulating materials onto the outer walls.

How to install foundation insulation from the outside using polystyrene foam

The most common way to insulate a foundation from the outside is to cover the walls with polystyrene foam materials. Due to the foamed structure, polystyrene retains heat well and, importantly, practically does not allow moisture to pass through. Cheaper is ordinary polystyrene foam, which is popularly called polystyrene foam. Extruded polystyrene foam, otherwise called penoplex, is more expensive due to the peculiarities of production and individual additives.

Polystyrenes are produced in the form of slabs of different thicknesses. Choose the right size taking into account the future use of the basement and the characteristics of the local climate. Most often, in Russian conditions, 5-centimeter slabs are installed, but if the basement is equipped for a wine cellar, where the temperature should be about 10 degrees, then 10-centimeter insulation is used. Particular attention is paid to gluing the corners, because this is where the freezing of the foundation begins. To do this, take slabs 3-4 cm thicker than the main insulation.

Foundation thermal insulation technology using extruded polystyrene foam

External foundation insulation with foam plastic

During production, the foam acquires a light structure, saturated with air bubbles, due to which it retains heat well. The same property made polystyrene foam moisture-permeable and ventilated. But the cells do not fit too tightly to each other, so during installation the material may crumble or break.

This insulation works great on soils with low levels of freezing, provided that it is protected from moisture on both sides.

External insulation of the foundation with penoplex

If you carry out insulation of the foundation yourself in an area where winters are harsh and the soil freezes to great depths, then it is better to use penoplex. It is three times more durable than foam plastic, so it will withstand the pressure of frozen soil and will not crumble. In addition, extruded polystyrene foam has a more elastic, closed-porous structure that does not allow moisture to pass through.

What is the difference between waterproofing and foundation insulation with polystyrene foam and penoplex?

If you insulate the foundation of a wooden house from the outside using penoplex, then you will not need to cover it with waterproofing material. All other stages of installation of polystyrene insulation are carried out according to the same scheme, as you can see by watching the video - how to insulate the foundation from the outside.

Soil preparation

A trench is dug along the entire perimeter of the foundation to the depth of the foundation. If the level of freezing in your area is low, then it is enough to dig just below the maximum limit. Since polystyrene is placed on a rigid base, it is worth covering the trench with a layer of sand and gravel (10 cm) from below and compacting them.

The deeper the trench is dug, the higher the thermal insulation of the foundation slabs will be.

Foundation preparation

Before insulating the foundation, clear it of any remaining soil and level out any uneven areas with cement mortar. For high-quality thermal insulation with polystyrene, a flat surface is needed to ensure maximum adherence of the insulation to the wall. The finished base must be primed.

Foundation waterproofing

The next stage of work is waterproofing the foundation. Why is it needed? There are no absolutely vapor-tight insulation materials, so some moisture will still seep into the insulation and penetrate into the concrete base. Moisture is not a problem for polystyrene, but concrete can crack in the cold. Therefore, it is necessary to coat the entire outer surface of the foundation slabs with liquid rubber or glue them with bituminous materials. It is easier to do this with a rubber compound, since it is sold ready-made. All that remains is to carefully move and go over the entire foundation with a spatula.

Rolled bitumen materials require the ability to operate a torch. Moreover, all joints must be heated very carefully so that there are no seams left through which moisture can pass into the thickness of the foundation.

You can also use bitumen-based mastics.

Pasting insulation boards

To fix polystyrene foam to the foundation, polyurethane glue or mastic based on bitumen and polymers is used. Be sure to read the ingredients in advance to ensure there are no organic solvents. If you find acetone, gasoline, etc. among the components, then such compositions will not be suitable for pasting. They destroy the polymer structure of the insulation and lead to ruptures of the slabs. Lubricate the polystyrene foam either spotwise or by brushing the base itself. Laying begins from the bottom of the corner, placing the slabs on a sand bed. Having laid the first row, they begin the second so that its seams fall in the middle of the underlying sheets, like brickwork. The slabs are connected with grooves into a lock, but if you have to trim the edge, then the joint must be lubricated with mastic or glue. When joining corners, it is recommended to blow out the seam with foam to close any possible cold bridge.

Laying outer protection

The last stage in installation is to isolate the insulation from external factors. The underground part can be covered with roofing felt and sprinkled with soil if you use penoplex. When laying polystyrene foam, additional waterproofing will be required. A waterproof film is glued over the roofing felt or a brick wall (half a brick) is placed. The outer part is reinforced with fiberglass mesh, plastered and covered with finishing material.

Protective brickwork will protect the foam from moisture coming from the soil

External foundation insulation with polyurethane foam

Some owners are looking for how to insulate the foundation of a wooden house as quickly as possible. To do this, it is worth using sprayed polyurethane foam insulation. Workers will mix the components right at the construction site and apply the liquid composition to the entire outer surface of the foundation within a day. After hardening, polyurethane forms a dense, continuous, seamless coating with characteristics similar to penoplex. True, in this case the cost of insulation will be high.

When choosing between external and internal insulation, give preference to the first option, since it is possible to insulate the foundation of a house from the inside only if there is high-quality ventilation in the basement. Experts believe that internal insulation shifts the dew point, as a result of which the foundation is completely under the influence of external moisture and cold and quickly begins to collapse. Insulation creates increased humidity in the basement, and only additional ventilation can eliminate it. And these are unnecessary expenses. In addition, part of your usable space will go under the “pie”.

Due to the absence of seams, sprayed polyurethane provides high thermal insulation

But if there is no other way out, then it is best to use liquid polyurethane foam, which provides maximum protection from moisture.

Without insulation of the foundation, the first floor will always suffer from dampness in the corners and cold.

Foundation thermal insulation- the most important stage in building a house. It is as important as wall insulation. Especially in harsh climatic conditions characterized by freezing of the soil to great depths.

An uninsulated foundation causes serious heat loss and is dangerous due to freezing and subsequent destruction of underground structures.

Thermal insulation of the foundation from the outside significantly reduces heat loss and serves as reliable protection for the foundation of the house from the influence of groundwater and negative temperatures.

Freezing is especially dangerous for building foundation structures, on which houses are usually built.

To avoid the negative impact of the external environment on the foundation, they resort to measures such as waterproofing the foundation and its insulation.

The largest volume of cold air enters the building through the foundation. And if the house has a basement used for any functional purposes (billiard room, laundry room), then special attention should be paid to it.

An unheated basement does not need thermal insulation. But it is necessary to insulate the basement part of the foundation, especially in houses built on stilts, in order to reduce heat loss at the floor level of the residential floor. Insulation helps retain heat in the house by cutting off the path of cold air into the house.

In addition, the foundation insulation layer plays a partial role in its waterproofing.

This means the thermal insulation of the foundation:

reduces heat loss;
reduces costs for;
reduces the impact of soil heaving on the foundation;
stabilizes the temperature inside the building;
prevents the formation of condensation on the internal planes of the walls;
performs mechanical protection of waterproofing and foundation structures.

Which insulation is more effective?

There are two ways to insulate a foundation - insulation at the pouring stage and subsequent insulation performed after the concrete casting has hardened. The first one is the most preferable.

The most correct approach to insulating the foundation during the construction process is permanent formwork. It is a structure into which a solution is poured. At the stage of its hardening, it plays the role of ordinary formwork, but after that it is not removed, but remains as an insulation layer.

Execution technology:

The first step is to prepare a pit from the outside of the perimeter.
At the bottom of the pit they do: they lay geotextiles, cover it with crushed stone, on top of which they put a perforated pipe, and then again a layer of crushed stone. The pipes are tied and taken to the well.
clean and dry, and then perform it.
Fill the prepared trench with sand or compact it layer by layer.

Insulation with mastics

A certain amount of insulation can be achieved during waterproofing work. For example, it is recommended to cover vertical foundation walls with several layers of bitumen mastic. This insulates cracks and small holes at the joints of the slabs through which heat can escape.

After this, a roll of waterproofing material is applied to the side surfaces. It will be an additional layer of thermal insulation.

Insulating the foundation with mineral wool

This method is used extremely rarely, because to carry it out it is necessary to build a frame, provide good protection for the mats from getting wet, and also build a protective wall from some finishing materials.

Execution technology:

The surface is cleaned and dried, defects are eliminated.
It is used to make a frame for mineral mats made of metal profiles.
Thermal insulation mats are laid on the frame and secured. The surface of the insulation is protected from external moisture by a vapor-permeable wind-waterproof film.
Protective walls or frames are erected.

Insulating the foundation with foam plastic

A modern and very effective method that qualitatively insulates foundation walls. Its advantage lies in the high thermal insulation characteristics of the material, ease of work, and the material’s resistance to mechanical damage and stress.

The disadvantage is the need for surface preparation, protection of the foam from rodents, as well as suitable waterproofing.

Execution technology:

The foundation is dug out, cleaned and dried. Remains of bitumen, fat, and oil are removed from its surface.
They produce.
The slabs are laid on glue, sold in the form of a dry mixture.
The surface of the foundation is protected from rodents with reinforcement mesh, laid on the same glue. Then the lower part of the foundation is backfilled with sand, and the upper part is secured using dowels intended for this purpose.

Insulation with polyurethane foam

This is a modern material for thermal and waterproofing both outside and inside the room. To use it, you must have special equipment that, under high pressure, sprays polyurethane foam layer by layer onto the required surface. The thickness of the polyurethane foam layer should be 5 cm. A similar insulating effect can be achieved using a layer of polystyrene foam 12 cm thick.

The advantages of polyurethane foam insulation are:

longevity;
high adhesive properties;
no need for additional vapor and waterproofing.
low vapor permeability;
seamless coating;
reliability;ne
low thermal permeability;

Disadvantages include the need to use special equipment and gradual destruction from solar exposure.

Insulation with polystyrene foam

Extruded slabs almost do not absorb or allow water to pass through. Therefore, this material retains its thermal insulation characteristics for a long time.

Advantages of insulation with this material:

long service life;
strength;
constancy of thermal insulation properties;
"inedible" for rodents.

When insulating with expanded polystyrene, remember that:

the corners of the building need “reinforced” thermal insulation,
to insulate the soil around the perimeter of the building, a layer of expanded polystyrene should be placed under,
The width of the blind area must correspond to the depth of soil freezing in the given climatic conditions.
before insulating the foundation of the house, the surface of the walls must be leveled and waterproofed;
The slabs are fixed by applying glue to them or by “melting” the waterproofing, to which the slab is then pressed and held for the time necessary for hardening.

How to insulate a shallow strip foundation

The installation of the slabs should begin from the bottom, the rows should be joined end to end. The thickness of the plates must be the same. The vertical seams of adjacent rows should be staggered.

Seams between slabs more than 0.5 cm thick must be filled with polyurethane foam.

The adhesive must be selected based on the waterproofing material. When using rolled and mastic materials based on bitumen, bitumen mastics that do not contain aggressive ingredients for polystyrene foam are used as glue.

Before insulating the foundation from the outside, be sure to wait until the bitumen waterproofing has completely dried.

Glue is applied pointwise to slabs located below the soil level, which allows condensation between the insulation and the foundation wall to flow down.

The slabs located in the ground are attached only with glue and pressed with a layer of earth.

For slabs located above ground level, it is imperative to use fastening dowels.

How to insulate a monolithic foundation slab

For the most effective thermal insulation of the floor and basement, you need to take care of the insulation of the foundation slab.

To do this, the insulation is laid on top of the waterproofing layer. Then, when using a power floor to fill, they use knitted reinforcement; in this case, it is enough to cover the heat insulator with plastic film with an overlap of 10 - 15 cm and gluing with double-sided tape.

When using a welded reinforcement structure, a protective screed from either cement-sand mortar will need to be made on top of the film, and welding work will be performed on top of this.

It should be noted that it is more correct to lay and insulate the foundation in the warm season, with a fairly high air temperature and not much humidity.

Measures to insulate a private home are mandatory for our climatic latitudes. At the same time, if everything is more or less clear with the insulation of walls and roofs and many manuals can be found in the public domain describing how to properly insulate the interior of buildings, then less attention is given to the insulation of the foundations of private houses. This article is devoted to the features of foundation thermal insulation and the results that are achieved with its help.

What goals are achieved by insulating the foundation?

Like waterproofing, insulation serves as a tool to protect the foundation from the negative influences of the external environment. If the walls and roof of the building are provided with thermal insulation, then the foundation becomes the main source of heat leakage from the home, especially if the house has a basement and it is used as a garage or for another purpose. As a rule, not the entire basement is insulated, but only the basement part of the foundation, in order to reduce the level of heat loss at the level of the first floor. This measure becomes mandatory if the house is built on a pile foundation.

As a result of thermal insulation of the foundation, the following objectives will be achieved:
general reduction in heat loss;
reducing building heating costs;
reduction of negative effects caused by soil heaving;
stabilization of the average temperature in the house;
preventing the formation of condensation on the walls;
additional protection of the waterproofing layer.

Two main methods of insulation

You can insulate the foundation of a private house both at the stage of pouring it and after the mixture has hardened. The second option is used to insulate an already built house, but it is not as effective as the first method, which is implemented only during the construction of the foundation. If possible, the outer side of the base is provided with thermal insulation, since in this case it provides additional mechanical protection.

One of the most effective ways to insulate a foundation involves the use of permanent formwork. It is mounted from expanded polystyrene and after the concrete mixture has hardened, it is not disassembled, but continues to serve as thermal insulation from the inside and outside of the foundation.

What materials can be used for insulation?

To create an effective thermal insulation layer, it is necessary to choose a material that does not absorb moisture and can withstand severe mechanical loads exerted by the surrounding soil. Taking into account these conditions, the following methods are best suited for insulation:

creating an insulating layer of expanded clay, sand or earth;
installation of an insulating structure made of polystyrene foam, polystyrene or materials with similar functional properties;
use of mineral wool;
insulation of the foundation of a private house using polyurethane foam.

These materials are suitable for buildings, as well as houses built from foam blocks. Their thermal insulation parameters and cost differ, therefore, when choosing a material, you should analyze the advantages and disadvantages of the selected material in order to find the best option.

Creating thermal insulation using expanded clay and sand

In the past, this method of external foundation insulation was the most popular. Its advantage lies in the property of expanded clay, which protects the surface of the foundation from moisture and creates an air gap that protects the structure from damage when the soil heaves during severe frosts. It is also necessary to note the simplicity of this technique - anyone could organize thermal insulation of the foundation of a house with their own hands without the use of special equipment.

The process of thermal insulation using expanded clay is carried out in several stages:

A pit is dug along the outer perimeter of the foundation;
The bottom of the pit is equipped with a drainage system consisting of a layer of crushed stone, a perforated pipe and another layer of crushed stone. The created pipeline is diverted to the well;
The surface of the foundation is cleaned and dried, after which waterproofing work is carried out;
The pit is filled with expanded clay or sand.

The advantages of this method include the low cost of materials and ease of work.

Insulation using sheet material

Before insulating the foundation of an already erected building, it is dug around the outer perimeter, and the width of the trench should be about a meter. Before starting work, the base wall must be thoroughly cleaned of dirt and dried, after which a latex primer material is applied to it. The primer fills all voids and ensures strong adhesion to the waterproofing layer. Laying of rolled waterproofing material is carried out with pressure. After sealing the joints and drying the waterproofing, you can start working with the insulation:

The special glue necessary to hold the slab in place is applied (along the perimeter of the insulating slab in a solid line and several strokes in the central part).
Individual slabs are pressed against the foundation, each new sheet is laid overlapping the previous one.
If the foundation wall is high enough and one row of slabs is not enough, a staggered arrangement is preferable to avoid the formation of seams.
If cracks form, they should be filled with putty using sealant or filled with foam.
The part of the insulation located above the ground is covered with finishing glue, fixing the reinforcing mesh to the surface. Before continuing work, you must wait three days for the glue to dry.
Formwork is assembled for the base. The slab is placed on a sand-crushed stone bed and covered with a reinforcing mesh.
After the blind area has dried, you can begin finishing work.

Using liquid polyurethane foam

Cured polyurethane foam provides, in addition to thermal insulation, additional protection from moisture. Thanks to the cellular structure, a 5-centimeter layer of this material is comparable in efficiency to a meter-thick polystyrene foam slab, which means that additional work from inside the basement will not be required.

The technique for applying expanded polystyrene is quite simple: the material in a liquid state is coated with the outer, previously cleaned wall of the foundation. Examples of the work can be found in numerous videos published on the Internet.

Advantages of polyurethane foam as a heat-insulating material:

increased adhesion;
complete absence of seams in the heat-insulating layer;
savings on additional waterproofing;
operational life within 40 years;
The material is environmentally friendly.

Unfortunately, there are also disadvantages:

relatively high cost;
special equipment is required to work with the material;
It is necessary to protect polyurethane foam from exposure to ultraviolet radiation.

Insulation with mineral wool

A rather rarely used method that requires the installation of an additional protective frame to prevent the cotton wool from getting wet. How to properly insulate the base of a building using mineral wool:

cleaning and drying the foundation wall, eliminating surface defects;
creating a frame from a metal profile or other material;
fixing the mats on a frame base, the outside of the wool is covered with a protective vapor-permeable film;
construction of an additional brick wall providing partial mechanical protection.

Insulation of a columnar foundation

The methods described above are applicable for monolithic and strip foundations, but they are not suitable for columnar foundations. To ensure thermal insulation of the space between the soil and the grillage, it will be necessary to create a special fence. This element is functionally similar to the plinth, but since it is not loaded, the requirements for structural strength are significantly lower. Sequence of work:

A 50-centimeter trench is dug in the spaces between the foundation pillars, a third of its volume is filled with a sand-crushed stone mixture;
A metal frame is laid on the pillow, on top of which concrete mortar is poured;
Solid brickwork is installed on the hardened concrete, leaving small ventilation holes.

Conclusion

This article described the basic methods of how to properly insulate the foundation of a private house, listing the order of construction work. For a more detailed introduction to the technology of foundation insulation, we recommend that you familiarize yourself with the advice of experts and watch several videos in which these techniques are used in practice.

What is the best material to build a house from?

Many novice builders, among those who are lucky enough to own their own country plot, and who want to carry out most of the work on their own, make many serious mistakes at first. And one of the quite common ones is ignoring the issues of reliable and insulated foundations.

The resulting “picture” is interesting - as a rule, everyone remembers the external design of the basement part of the wall. Without in any way belittling the importance of neat finishing, we agree that it will not subsequently determine the level of comfort of living in the house and the durability of the building’s structural elements, but the quality of hydro- and thermal insulation directly affects this. Therefore, let's look at a very important topic - complete insulation of the foundation base from the outside. By the way, some technologies for thermal insulation of this part of the foundation also require its finishing.

Why is it generally necessary to insulate the foundation, and the basement in particular?

From a layman's point of view, the very formulation of the problem may not seem entirely clear - what is the point of insulating the foundation? After all, for the most part it is not directly adjacent to residential premises, and, it would seem, cannot in any way influence the microclimate in them. And if basements are not created, or they do not require maintaining a certain level of temperature, then why even start one?

This is an extremely common misconception! The foundation, like other structural elements of a building, needs reliable insulation, and this need is caused by a number of reasons of various properties. And, probably, first of all, thermal insulation of the foundation is a task aimed at maximizing its strength and durability, on which, of course, the operational life of the building itself directly depends. Let's look point by point and start with the most common - strip foundation.

First of all, it must be said that truly high-quality thermal insulation should include comprehensive insulation - both the vertical walls of the foundation (basement) and the blind area around the perimeter of the building. Otherwise, it will be naive to talk about the effectiveness of such measures.

A massive reinforced concrete foundation without thermal insulation on the outside will always be a powerful cold accumulator in winter, from which it will spread to adjacent building structures. It is clear that the floor level of the premises on the first floor, as a rule, is located above the plinth line, and the walls and ceilings have their own insulation. But such proximity always leads to excess heat loss and, accordingly, to completely unnecessary, extra costs for energy resources used for heating purposes. Practice shows that even just competent insulation of the foundation gives a significant, up to 20÷25%, saving effect, all other conditions being equal.

1 – ground level;

2 – foundation base;

3 – basement part of the foundation;

4 – building wall;

5 – ceiling (floor) of the first floor;

6 – insulation of the external wall;

Of course, the scheme is not a dogma, and some variations are possible. So, in particular, the layer of horizontal insulation (under the blind area) can be located buried, right down to the level of the sole. But even in this case, it must be laid so that there is no gap between it and the vertical thermal insulation of the foundation wall.

Finding out the required thickness of insulation

It is probably clear that the thickness of the foundation insulation must obey certain rules. The same Penoplex boards are available in a wide range of thicknesses, and it is not difficult to purchase the necessary material for single-layer or, if necessary, even two-layer thermal insulation. But how to find the right thickness?

To do this, you can carry out certain thermal calculations using formulas or even just tabular data.

Vertical thermal insulation of the foundation

Let's start with the vertical layer of insulation. The calculation will be based on the following formula:

Rsum = hф/λф + hу/λу

Rsum– total heat transfer resistance (measured in m²×°K/W) that a building structure, in this case a strip foundation, must have. This is a standardized tabular value established by Construction Norms and Rules (SNiP) for all regions of Russia, depending on the characteristics of their climate. If you wish, you can find tables on the Internet for various areas; this parameter is probably known in all local construction or design organizations, but it will be even easier to take the value from the diagram map below.

Please note that for each region three values of this thermal resistance are indicated: for walls and enclosing structures, for coatings and for floors. In this case, we are interested in “for walls” - in the columns these are the top values, highlighted in purple.

hf And λf– parameters characterizing the thermal characteristics of the foundation tape itself: this is the thickness of the tape in meters ( hf) and the thermal conductivity coefficient of reinforced concrete is a tabular value.

hу And λу– similar parameters of the insulating layer.

This means that if the thermal conductivity coefficient of the selected insulation material is known, then it is easy to calculate its required thickness using simple arithmetic operations.

And in order not to force the reader to plunge into independent calculations, we suggest using a special online calculator, which already contains all the thermal dependences and the necessary tabular values.