Insulation of the foundation from the inside. Proper insulation of the foundation of a private house in various ways How to insulate the foundation under the floor

Owners of private houses, in an effort to make the house warm, sometimes pay attention only to walls and ceilings. At the same time, they forget that the insulation of the foundation is an equally important point.

As a result, there are problems of cold floors and excessive heating costs. Once you have invested in the insulation of the supporting base, you can save an impressive amount on heating bills.

What caused the need for thermal insulation?

A significant part of the cool air enters the room through the foundation. Therefore, the designs of many buildings are built in such a way as to raise the floors above the ground. Warm, heated air rushes up. When the roof is not insulated, heat seeps out. And the room is filled with cold air, which penetrates through the floors of the building. Therefore, the need for thermal insulation of the supporting base is obvious. If the walls are in frozen ground, the room will have to be constantly heated.

When it comes to maintaining heat in an old house, it should be remembered that all components of the system must retain heat: the foundation, walls, ceilings and roof. If at least one thing will release heat, then the whole building will not be able to keep it at a high level.

High-quality insulation of the foundation can reduce the impact of groundwater and cold on the base of both wooden and stone buildings.

Isolation methods

All methods for warming are usually divided into two types. The first - before pouring the foundation, the second - the insulation of the finished structure. The first option is preferable and it is he who is used more often. In severe winter conditions, the concrete foundation is insulated on both sides.

Concrete is known for the almost complete lack of thermal insulation, it cools easily and heats up just as easily. During construction, they use both a heater, which is mounted directly into the formwork, and a special fixed formwork. Such panels are many times more expensive than simple ones, but the amount of costs is lower than the price of dismantling a simple formwork and subsequent insulation.

Insulation of the foundation of an already operated house is a complex and responsible undertaking. In cases where the building was built with insufficient foundation depth, freezing of the soil under it will be very strong. In such situations, for thermal insulation, the foundation is dug both inside and outside, and later a heater is laid. At the same time, to prevent freezing of the floor in the basement of the old building, it is sprinkled with expanded clay.

Already long years the most commonly used methods of foundation insulation remain unchanged: with the help of earth, expanded clay or expanded polystyrene.

Earth insulation

This option is the most economical, despite the impressive volumes of sand that will have to be unloaded and leveled. The method lies in the fact that the earth is filled up to the level of the future floor, as a result, the entire basement and foundation are underground.

Ground insulation is carried out before the construction of the house. Be sure to provide a ventilation shaft for the basement.

Advantages of the method:

insulating with soil, you do not have to buy a heater;
the house will not freeze through the basement.

Flaws:

large volumes of earth and sand will have to be leveled;
soil - a weak heat insulator;
the walls of the foundation will let the cold into the room, albeit in smaller quantities.

Thermal insulation with expanded clay

One of the cheapest and most effective methods. Sometimes builders combine insulation with soil and expanded clay.

In the process of pouring the foundation, expanded clay is placed in the inner part of the prefabricated formwork. This method is used for both wall and floor insulation, in both cases it is quite effective. The unique properties of expanded clay are contained in its porous structure, due to which it does not allow moisture and cold to pass through, retains heat well. The only losses occur due to the fact that the cavities between the granules are filled with cement, and it is a conductor for cold.

Expanded clay insulation is often used for strip foundation. With a low-depth foundation, the material is used to insulate the floor in order to completely get rid of the freezing of the earth in the basement.
If the insulation occurs after pouring, then the formwork is usually used the lightest, since expanded clay is practically weightless. Sometimes slate sheets are used as formwork.

Expanded clay is a fragile insulation. When used for floor insulation, they are laid on expanded clay mineral wool and film to protect against moisture.

What about styrofoam?

When deciding how to properly insulate the foundation, often the choice falls on the foam insulation method. This is a versatile and affordable material.

Styrofoam is sold in sheets that are easy to install. Therefore, its use allows you to do all the work with your own hands.

Waterproofing

Before fixing the sheets of insulation, it is important to waterproof the surface. There are many waterproofing methods:

applying several layers of bituminous mastic;
waterproofing with roofing material;
surface plastering;
applying special penetrating compounds.

Slab laying

After providing waterproofing, expanded polystyrene sheets are mounted on the surface to be insulated. Sheets are laid from the bottom of the foundation to the level of the future floor. The insulation is fixed with the help of special adhesive compositions, which are applied pointwise to its surface. It is necessary to lay sheets of polystyrene foam close to each other in order to obtain monolithic surface. The seams between the insulation boards close up mounting foam.

Expanded polystyrene eventually collapses under the influence of sunlight, so it should be securely covered from above with facing panels.

Thermal insulation around the perimeter

Before you insulate the foundation around the perimeter, you need to remove the soil along the entire base of the building to a depth of about half a meter and a width of about one and a half meters. After creating the trench, the sand is backfilled by about 20 cm, it is carefully compacted.

Styrofoam plates are installed on the "sand cushion". For additional reliability, insulation materials are attached using special adhesives, for example, bituminous mastic. The joints formed between the plates are blown with mounting foam. You can also fill the gaps with cold-applied bituminous mastic.

After fixing the insulation and completing the other related work, sand is again covered with a layer of at least 3 m.

The corner zones of buildings lose more heat than flat surfaces. Therefore, in these places you should use a larger (one and a half times) layer of polystyrene foam.

The advantages of perimeter insulation with polystyrene foam are as follows:

the design of the insulated foundation is protected from the appearance of deformations and cracks;
at the same time the basement is also thermally insulated;
polystyrene foam has good performance properties, which makes it a fairly durable material.

Also, expanded polystyrene can be used for internal insulation of an old house if it is impossible to carry out external insulation. To do this, the walls are glued from the inside with foam boards. A room insulated in this way can become a full-fledged room.

The use of penoplex

Penoplex material is more perfect than polystyrene. Insulation of the foundation with foam plastic prevents its deformation, the building will last longer.

Penoplex has a structure with closed pores, so that it is not subject to the destructive action of water. Other important virtues material lies in its strength and low thermal conductivity.

How is the installation carried out?

Penoplex can be installed only a week after the implementation of waterproofing, the methods of which were described above.

Penoplex is produced in the form of plates with grooves of a certain configuration. These grooves provide a very tight fit of the plates to each other without gaps.

Fastening is carried out with special adhesive compositions. You need to choose only those compounds that are not capable of destroying the insulation. Glue is applied pointwise, gradually processing small areas surfaces. The slab is applied to the foundation and pressed for 40 seconds. After gluing the slab, proceed to the next section. The process is continued until the entire surface of the base of the building is insulated.

It is necessary to glue the plates so that they protrude 35–50 cm upwards. After the installation is completed, the resulting voids are covered with non-porous materials. At the end, thermal insulation of the soil along the perimeter is carried out.

High-strength sealed board with PU foam

Polyurethane foam or PPU - modern construction material, which has many advantages. He is characterized low thermal conductivity, strength, durability and environmental friendliness. It is easy to work with polyurethane foam - no additional fasteners are required for installation, its application to the surface is quick. PPU has high waterproofing properties that prevent moisture from entering, thereby protecting the building.

The main advantage of using polyurethane foam as a heater is the inability to spoil the result - the final coating is always obtained without cracks, bumps and joints.

How to work with polyurethane foam?

The foundation is insulated with polyurethane foam by spraying the insulation onto the surface using special installations. The resulting foam is firmly connected to the base of the structure, filling all cavities. It turns out a high-strength plate, very hard and tight. Since the material has a closed structure and there is no air gap, condensation cannot appear in such a product.

Thermal insulation of the foundation with polyurethane foam is the most effective method. It is suitable for both new buildings and for thermal protection of an old house. But the cost of such insulation is high and it is impossible to carry out the work on your own, since special equipment is required.

There are many options for waterproofing and warming the foundation, it remains only to choose which one is most suitable.

Most owners of private houses do not consider it necessary to insulate the foundation, believing that this is a waste of money. Thoughts about the need to insulate the basement from the outside come when they become visible problems with dampness and mold on the walls, and the plinth begins to crack. Do-it-yourself waterproofing will help to avoid these troubles, we will tell you how to do it in the article.

Why is the foundation warm

Basement insulation is just as important as house wall insulation. Through the foundation, the room loses about 20% of heat. Many people think that it is enough to insulate only the basement, but this is a gross mistake. Since the destructive force of water and low temperatures continues to act on the base. Moisture, getting into the pores of the foundation, freezes when exposed to low temperatures and, expanding, destroys the structure. Microcracks appear, which become cold bridges, and when they grow, they can lead to the destruction of the building as a whole.

Insulation of the foundation prevents its destruction

External insulation eliminates the effect of low temperatures and groundwater. The dew point shifts to the insulation layer, and the foundation concrete does not change its properties. Warming is especially important in regions with a harsh climate and heaving soil. Such soil, freezing by 15%, is able to move 35 cm, which entails deformation of the base. On such soils, the depth of the foundation should be below the freezing point, and the insulation is done not only vertically, but also horizontally.

The benefits of insulation

With an uninsulated foundation, cold air from outside enters the living space through the flooring. Therefore, when building a house, the floors are raised above the ground level. Without insulation from the outside, constant dampness in the basement and cold floors in the house are guaranteed, which reduces the level of comfort. So, what facts speak in favor of insulation:

the heat loss of the building is significantly reduced, which means that the financial part of the budget for heating will also be reduced;
the effect of soil heaving forces is leveled;

Benefits of basement insulation

prevents the formation of condensation and mold;
prolongs the service life of the foundation structure;
protects waterproofing from mechanical damage;
it is easier to block the bridges of cold.

Advice. special attention building corners are required. In these places, the thickness of the heat-insulating material is doubled.

Warming methods

When choosing a material for insulation, attention is paid not only to the cost, but also to its main characteristics, namely: hygroscopicity and resistance to deformation. There are several ways to insulate:

Plate heaters: extruded polystyrene foam 200 kPa, foam glass, polyurethane foam and synthetic rubber in the form of foam.
Backfilling with bulk materials: expanded clay, boiler slag.

Most often, polyurethane foam or extruded polystyrene foam is used for insulation.

Advice. On the plates, which are located below ground level, glue is applied pointwise. This is necessary so that the condensate formed between the waterproofing and the insulation flows freely into the equipped drainage.

Expanded clay insulation

Before the advent of new generation insulating materials, expanded clay was often used. Its main advantage is its low price, but the level of thermal conductivity of the material suggests its use in large quantities. So dignity becomes a disadvantage. It is rational to put it into action as additional insulation.

Expanded clay insulation

Warming is carried out as follows:

the foundation is dug up to the sole, to a trench width of 1 m;
clean the surface of dust;
in the absence of waterproofing, apply bituminous mastic;
equip drainage if the groundwater level is high;
a film is placed at the bottom of the trench from the wall to the drainage;
the trench is filled with expanded clay and a blind area is made.

Sheet insulation technology

When erecting a new building, insulation work begins after the installation of the floor slab. If the house has already been erected, then the foundation is dug around the perimeter to the base to a meter wide. The walls are dried, all dirt is removed. With a close level of groundwater, drainage is arranged. After complete drying, a latex-based primer is applied to the foundation walls. It fills small voids and provides a strong adhesion of the waterproofing to the basement surface. Rolled waterproofing is laid, strongly pressing with a roller. Joints are covered with sealant for reliability. Wait until the waterproofing dries, and then proceed to laying the insulation.

Scheme: insulation with sheet material

Advice. Do not use plates torn from the surface or move them after the adhesive has hardened.

The advantage of extruded polystyrene

Styrofoam boards are considered the best option for private construction. Since they have a long service life and high compressive strength. Practically do not absorb and do not pass moisture. For a long time it retains thermal insulation characteristics precisely because of its low hygroscopicity.

Thermal insulation of the base with extruded polystyrene foam

These plates are produced with special grooves. Moisture is drained through them. In tandem with geotextiles, polystyrene, in addition to insulation, performs the role of waterproofing and wall drainage.

Advice. Ordinary polystyrene, although it has an attractive price, is completely unsuitable for insulating the foundation. It absorbs moisture and breaks down quickly.

Polyurethane foam is applied in foamed form to the cleaned surface of the foundation. It combines the properties of waterproofing and thermal insulation. 50 mm of polyurethane foam is equal to 1.2 m of polystyrene foam. The material hardens very quickly, forming a cellular structure. Foam hermetically envelops the foundation, leaving no gaps and without forming seams, unlike tile insulation. The advantages of polyurethane foam insulation include:

lack of seams in the coating;
high adhesion of the material;
no need for waterproofing;
low vapor permeability;
service life of more than 40 years;

Insulation with liquid polyurethane foam

low thermal conductivity;
environmentally friendly and biologically neutral.

There are only three cons. This is a high cost and the need to purchase special equipment for laying. Polyurethane foam is destroyed under the influence of solar ultraviolet radiation.

Water drainage from the basement

Together with insulation, it would be good to provide for drainage so as not to dig out the foundation twice. Drainage pipes are laid below the level of the base of the foundation or below the level of the basement, if any. A gravel cushion is poured with a slope of 5 degrees. A drainage pipe is placed on top of it, wrapped in geotextile, and gravel again on top. Geotextiles will prevent clogging of drainage holes. Ground water will flow through the pipes into the drainage well.

Foundation drainage system

With knowledge of the advantages and disadvantages of insulation, you can choose the material that suits you best. Properly spend construction works, and you will provide comfort and warmth in the house for a long time, as well as a long service life of the building.

Insulation of the foundation with polystyrene foam: video

Insulation of the foundation of a private house: photo

When building houses, many people ask themselves: is it necessary to insulate the foundation? This process is optional.

Insulation of the foundation will reduce the negative impact exerted on it by the change in ambient temperature, protect its base from freezing, and also reduce the heat loss of the house.

It is possible both outside and inside. According to experts, it is better to do external insulation. This is due to the fact that the outer insulation:

protects the base from freezing;
has a beneficial effect on the quality of concrete, and, consequently, on the entire structure of the foundation;
requires a waterproofing device, which provides reliable protection of concrete from the effects of ground and other types of water;
reduces the negative impact on the foundation from changes in ambient temperature.

However, sometimes external insulation is not feasible. In this case, resort to internal insulation of the foundation. This method also has its advantages:

internal insulation plays an important role in shaping the microclimate inside the house;
protects the basement from groundwater;
helps to avoid condensation inside the basement.

However, internal insulation does not protect the foundation from negative environmental influences (soil heaving, temperature changes, groundwater), and this is a big drawback of such thermal insulation. And this can lead to the destruction of the foundation. right, see below.

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How to insulate the foundation from the inside?

There are several options for how to insulate the foundation from the inside, you can use various heat-insulating materials. The cheapest option is foam. It provides excellent thermal insulation, is resistant to moisture, and is durable. However, for its installation, you will need special glue, you will have to cut it to lay it on the surface. In conditions of limited space, this is sometimes difficult to do. Expanded polystyrene is also inexpensive, and its installation is similar to polystyrene. However, this material has a low resistance to moisture.

A good option is polyurethane foam, which is applied by spraying. It is easy to work with it in a limited space, it forms a monolithic layer on the surface, providing excellent thermal insulation. Such a heater will last a long time and reliably. Polyurethane foam is applied from a balloon. In this case, it is recommended to treat the surface of the foundation, basement walls, floor and ceiling. However, its cost is quite high. Therefore, the most widespread is still foam.

After installation thermal insulation material start finishing the ceiling, floor and walls.

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External thermal insulation

Now let's consider . For external thermal insulation, foam, polystyrene foam and polyurethane foam are used. Regardless of the type of insulation, the following preparatory work is carried out.

Initially, you need to bare the foundation. To do this, a trench about 0.5 m wide and a depth reaching the base of the foundation breaks out around the entire perimeter of the house. After that, the surface is cleaned of earth, dirt and dust. If necessary, the walls are aligned. The next step is the laying of waterproofing material. It can be penetrating waterproofing, bituminous mastic, liquid rubber or roofing material.

And after that, the insulation is laid. Styrofoam and expanded polystyrene are glued to a special adhesive, or to bituminous mastic. The joints between the sheets are further filled with mounting foam, which eliminates the penetration of moisture between the seams.

The upper edge of the insulation should rise by about 30-40 cm from the surface of the earth, which will protect the foundation from the cold and groundwater in case of an increase in their level.

After laying the heat-insulating material, they begin to backfill the trench. First, a layer of sand about 10-15 cm thick is laid on the bottom, on it are the remains of insulation (if they were formed after work), gravel 50-60 cm thick. And the final layer is external, which depends on the personal preferences and capabilities of the owner of the house. It can be concrete, asphalt, sand. For a more aesthetic look, you can lay decorative tiles.

Often, expanded clay is used to insulate the foundation from the outside. Recently, due to the advent of more efficient and technologically advanced heaters, the material has become less successful, but still finds application in insulation to this day.

Thermal insulation with expanded clay is more laborious and less effective; for good insulation, it is necessary to fill up a sufficiently large layer of material. To do this, a trench is dug out with a width of about 1 m and a depth reaching the base of the foundation. A waterproofing material is laid at the bottom of the trench, after which the pit is covered with expanded clay. The material is covered from above with another layer of waterproofing, which is sprinkled with earth or sand.

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Warming of various foundations

It depends not only on the heat-insulating material, but also on the type of base itself. In the construction of private houses, the following types of foundations are used: tape, monolithic (or slab), pile and columnar. They differ in their design, properties, construction technology and, accordingly, insulation technology.

The most common is the tape base. Above, the technology of how to insulate the foundation of this particular type was considered. It is worth considering ways to insulate other types of structures.

Insulation of pile-screw foundation. This type of base is the most rapidly erected and economical. It is used on unstable soils or in the construction of light buildings. According to professional builders, it is inappropriate. The most efficient will good insulation floors on the first floor.

This type of foundation is the most reliable today, it can withstand the load from a house of several floors. In its design it is similar to the tape, but in the corners and joints bearing walls poles are added. They increase the reliability and stability of the base.

If the thermal insulation of the strip foundation is a fairly simple process, then you will have to work hard with the columnar type. For insulation, a pick-up device is required, which will connect the pillars to each other and to the grillage. The pick-up can be made from various materials, lumber, chipboard or metal frames are most often used. Warming is carried out as follows. A trench is dug between the pillars, the depth of which is about 30 cm. Sand is poured into the bottom. Then bars are attached to the posts, to which boards or chipboard are then nailed. In the case of metal frames, metal profiles are used instead of bars.

Waterproofing is laid on the fence and then on the grillage, a heater is attached, and a vapor barrier is on top. If necessary, finishing can be done. The remaining gap between the insulation and the soil can be covered with expanded clay or a blind area can be made. This completes the thermal insulation of the base.

Thus, it was considered how the foundation is insulated. Thermal insulation is most appropriate when installing a strip base; in other cases, floor insulation is more effective.

Foundation insulation procedures are aimed not only and not so much at combating heat loss, although this is an important factor for the overall energy balance in the house, but at maintaining the bearing capacity of the foundation. The emerging cold bridges between the walls and the supporting surfaces of the foundation blocks are not so difficult to eliminate, it is more important to ensure that the condensate and moisture accumulating in the microcracks of the concrete do not freeze and thereby turn the durable material into stone chips.

How to insulate the foundation of a private house

Regardless of the design of the foundation and the location of the building, when arranging the foundation system, it is necessary to ensure quality manufacturing two most important systems- waterproofing protection of concrete with drainage system soil around the house and thermal insulation concrete surface. Only in this case, two interrelated procedures can protect the base of the foundation from the destructive effects of the soil.

Despite the apparent external simplicity, warming the foundation of a house requires a very careful and scrupulous attitude to work. If, due to the rise of the soil, the outer insulation on the concrete is torn off or split, most of the work will go down the drain.

Therefore, at the initial stage, you need to choose a material and a way to insulate the foundation of a private house:

Use for insulation a backfill thermal insulation system in the sinuses and places where the soil adjoins the outer surface of concrete blocks;
Insulation of the foundation and blind areas with sheet material such as foam, foam glass or extruded PPS;
Foaming walls with polyurethane foam.

For your information! The most effective will be the combination of interior cladding and insulation of the outer surfaces of the foundation's load-bearing structures.

If the insulation is performed exactly according to the technological map recommended by the manufacturers of thermal insulation materials for specific foundation systems, the dew point or the place where condensate forms will be brought to the surface of the heat insulator. Thus, the effect of "freezing" the soil and the cutting effect of clay soils during severe frosts will decrease.

What gives the foundation external and internal insulation

There is a certain kind of delusion that the presence of a basement under the building will be a sufficient condition for heating the walls of the foundation and the ground, especially since the depth of such premises almost always exceeds the level of soil freezing. In reality, the picture is a little more complicated.

With the onset of frost, the foundation and the basement floor take a large number of heat that goes into the ground at a tremendous speed. As the top layer of the earth freezes, the soil becomes compacted, the vast majority liquid water around the foundation turns into ice crystals, and from that moment the thermal conductivity of the soil decreases sharply. It remains cold, dense and conductive, like snow or ice pellets.

Heat loss through the walls in the basement is reduced, and through the floor - increased. A small layer of soil adjacent to the outer walls of the foundation is in an unstable state. The situation goes like this:

Firstly, the soil layer adjacent to the concrete contains a large amount of liquid water, which, on the one hand, is in contact with warm concrete wall, on the other hand, with frozen soil;
If no measures are taken, the water will be squeezed out by the soil through the thickness of concrete into the basement and then freeze on the walls and ceiling;
If concrete is insulated, then the liquid part of the water will constantly be on the border of the insulation and the soil, accumulate and go down into a warmer drainage section foundation.

Important! Therefore, it is necessary to carry out the insulation of the floor and walls of the basement. Insulating the walls inside the basement will help increase the ventilation coefficient and quickly get rid of condensation on the walls.

Do I need to insulate the foundation of a house without a basement?

If the house does not have a basement, the level of freezing of the soil under the foundation blind area will be much lower. Frozen ground pressure side surface and the heel of a shallow foundation will be much higher. To reduce freezing, it is necessary to take a number of additional measures:

Insulate the foundation array, both from the outside and from the inside of the walls of the structure;
Perform thermal insulation of the space under the foundation floor slabs, best of all in the form of backfilling with a thick layer of expanded clay;
Insulate the base of the foundation blind area to a width of at least 60-70 cm. This will reduce heat loss from concrete blocks in the most “frosty” place of construction.

Important! Thus, as a result of insulation, you will be able to redirect the main heat flows into the thickness of the concrete, thereby eliminating its destruction at low temperatures.

In addition, if drainage and drainage in a shallow foundation are built in accordance with all the rules, you can not be afraid of swelling of the soil.

How to insulate the foundation of a house

Among the above methods of insulation, the simplest is the bulk version of thermal insulation. Granular material with a low coefficient of thermal conductivity, most often expanded clay or slag granules, is poured into a ditch or sinus adjacent to the vertical wall of the foundation. The thickness of the poured layer can reach 60-70 cm, which provides high insulating properties. Much less often, a masonry form is used to insulate the foundation, in which the granules of thermal insulation are packed in plastic bags. Instead of a loose form, the foundation is insulated by laying packages of 5-10 kg of material, which are fixed with a mesh.

The masonry form is considered more preferable for warming, since in this case there is no absorption of moisture by the filler. Expanded clay and slag after a long stay in a humid environment can be saturated with moisture and partially lose the effectiveness of thermal insulation and insulation.

The most effective heat insulators can be called tiled forms of foamed polystyrene masses. When building new houses, they most often resort to insulation with extruded PPS or foam. Warming is carried out in the form of a multilayer "sandwich". The first layer of insulation on the concrete is mastic waterproofing. After drying in a checkerboard pattern, plates of pressed polystyrene foam are laid out on the glue. Roll insulation and a layer of geotextile fabric are applied over the heat insulator. Such a scheme of insulation allows you to effectively resist moisture and retain heat even with a high water content in the soil.

In theory, heat-treated polystyrene foam should not accumulate moisture, but in practice, during severe frosts, the dew point shifts inside the insulation, and water vapor condenses inside the smallest pores. Therefore, in polystyrene plates for insulation, drainage channels are provided that allow condensate to be discharged into the drainage zone. It is clear that conventional foam plastic under such conditions will fail rather quickly due to low mechanical strength.

Polyurethane foam has excellent insulating properties. Foamed polymer insulation is applied to the waterproofing coating of the concrete surface with a pneumatic sprayer without any additional operations. The thermal conductivity of polyurethane foam can vary between 0.023 - 0.029 W / m * K, which is on average 10-15% better than that of extruded polystyrene foam. In addition, with the help of polyurethane foam, it is quite easy to insulate the basement with the most complex and uneven surfaces.

How to properly insulate the foundation of an old house

The complexity of work on the insulation of foundations lies in the impossibility of excavation in close proximity to the foundation blocks. Attempting to dig a trench and expose the foundation strip may cause the building to settle.

In such a situation, the insulation of the foundation is carried out in two main ways.

The safest for the construction of the house will be the insulation of the basement and foundation blocks using internal thermal insulation walls. The laying technology is approximately the same as for outdoor work, but the floor is most often supplemented with a drainage system with the laying of geotextiles and backfilling with a layer of granular material - expanded clay or foam glass

In the second case, the foundation is insulated on the outside of the walls. To do this, the soil next to the walls is pulled out in sectors, leaving power elements in the form of "bridges" 40-50 cm wide and 1.5 m apart. A mixture of foam glass coated with bitumen is laid in the dug sinuses, the laid layer is carefully compacted and closed with a blind area from concrete.

Conclusion

Insulation of the foundation makes it possible to maintain the strength of the foundation and basement walls even in the most adverse climatic conditions. Costs of this kind for finishing the walls of the base will guarantee the stability and strength of the entire building.

In this article I will tell you how to insulate the foundation various types. This will allow you to independently make your home more economical and comfortable.

Do I need to insulate the foundation

Often, beginners ask on the forums what is the best thing to do, insulate - the foundation or the floor? In fact, the question is incorrect, since both operations are aimed at solving different problems.

So floor insulation prevents the penetration of cold into the room through the ceiling.

The thermal insulation of the foundation performs the following functions:

protects the base from moisture, as well as multiple freeze / thaw cycles, and other negative factors. Thus, the insulated foundation is more durable;
prevents cooling of the ceiling and walls as a result of contact with the frozen foundation, respectively, reduces the overall heat loss of the house;
protects the basement from low temperatures, if any. This allows you to store vegetables and other products in it.

Therefore, if you decide to insulate the house, it is highly desirable to insulate the foundation as well.

External insulation of the strip foundation

First of all, consider how to insulate the strip foundation, which is the most common.

There are two ways to insulate such a base:

thermal insulation outside it is this method that allows you to protect the base from freezing and other negative factors;
insulation from the inside - as a rule, it is performed in cases where there is a basement under the house or ground floor. This procedure allows you to make the room warmer and, accordingly, reduce heating costs.

Often, internal insulation is performed together with the external one. Next, consider both options for thermal insulation.

So, the insulation of the strip foundation from the outside can be divided into five stages:

Preparation of materials

First of all, you need to decide on the choice of thermal insulation material. Usually, expanded polystyrene or extruded polystyrene foam is used for these purposes.

this material has a much higher strength than polystyrene - 0.2-0.5 MPa versus 0.07 MPa for polystyrene;
not afraid of moisture;
durability is much higher than that of polystyrene;
has low thermal conductivity - 0.027-0.034 W / mK versus 0.037-0.043 W / mK for foam.

The density of extruded polystyrene foam for external thermal insulation must be at least 33 kg / m 3 so that it has sufficient strength. On sale you can find a special insulation for the foundation, for example, Penoplex Foundation.

The only drawback of expanded polystyrene is the high price, which averages 4500 rubles per 1m2.

In addition to thermal insulation, you will need the following materials:

liquid waterproofing, for example, bituminous mastic;
geotextiles for arranging drainage;

drainage;
glue-foam for penoplex;
rolled waterproofing, for example, roofing material;
materials for pouring the screed (needed to equip the blind area).

Excavation work

External insulation of the foundation of a private house begins with excavation, unless, of course, you are engaged in this procedure at the construction stage.

Earthworks are carried out as follows:

First of all, you need to dig out the strip foundation. To do this, dig a trench to the entire depth of the foundation, about one and a half meters wide. After that the foundation should be left for a while so that it dries well;

Next, you need to perform drainage. It is especially necessary if groundwater is located close to you or if rainfall is abundant in your area.
To arrange drainage around the perimeter of the house, you need to dig trenches at a distance of half a meter from the foundation. The depth of the trench should be such that the drainage pipe is located at the level of the base of the foundation.;

fill the bottom of the trench with sand and gravel. The thickness of the layers should be about ten centimeters;
then the bottom of the trench should be covered with geotextile with a twist to the edges;
after that, drainage pipes are laid in the ditch. In this case, it is necessary to withstand a slope of at least 2 cm per meter. The drainage system must be connected to storm sewer or take it to a storm well;
then fill the trench with crushed stone and wrap the pipes with the edges of the geotextile.

It is necessary to start excavation work in dry, warm work. Therefore, it is best to deal with the insulation of the foundation in late spring or summer.

On this excavation until completed.

Foundation preparation

Now it is necessary to prepare the surface of the foundation for further insulation.

The work is performed in the following sequence:

the dried foundation must be cleaned of soil residues and other dirt. In this case, it is necessary to remove the chipping sections of concrete. To clean the surface, you can use a metal brush;
protruding areas that will interfere with the installation of insulation must be removed. Try to keep the surface as even as possible, as the durability of the foundation depends on it;

to improve the adhesion of the mastic, the foundation must be treated with a bituminous primer using a roller or brush;
after the surface has dried, the foundation is waterproofed. To do this, apply bituminous mastic on its surface with a roller or brush. I recommend using a ready-to-use mastic that does not need the addition of a solvent or heating.

All recesses, cracks, etc. must be filled with mastic in order to form a continuous coating with a thickness of about 2-4 mm.

Now you need to wait for the mastic to dry, and you can start warming the foundation of the house.

Insulation installation

The installation instructions for the penoplex look like this:

apply glue to the back of the insulation. Glue should be located around the perimeter of the plate, as well as in the center;
then the plate must be applied to the surface of the foundation and lightly pressed down. Start pasting the foundation from the corner.

Try to place the tiles as close to each other as possible. Some types of extruded polystyrene foam have chamfers, due to which they are connected into a lock;

as a rule, it is impossible to ideally paste over the foundation with insulation boards. Therefore, you need to inspect the walls and fill the existing gaps with adhesive foam.

This completes the heating process. I do not recommend additionally fixing the insulation to the foundation with dowels, since it will already be securely fixed with soil. In addition, when installing dowels, you will have to make holes in the foundation that will violate its integrity.

The arrangement of the blind area

Now you need to make an insulated blind area by doing the following:

the pit along the perimeter of the house must be covered with earth so that a trench remains about 30 cm deep from the ground level;
then fill the trench with sand about ten centimeters thick and carefully tamp;

on top of the trench, roofing material should be laid close to the walls of the house. Joints of roofing material, which should overlap each other, glue with bituminous mastic;

then foam is laid on the waterproofing;
a screed is poured over the foam plastic according to the standard scheme.

This completes the insulation of the foundation from the outside.