Greetings, dear readers, today we will consider an interesting and very important issue that arises at the construction stage, namely, how to properly insulate the foundation of a private house and how to choose a heater for the foundation of a house.

It is worth noting that until recently, professional builders and amateur builders, building and repairing their houses on their own, argued about the feasibility of insulating the foundation. There was always a question whether it should be insulated or not?

Today, thermal insulation of the base of the house is a generally accepted practice. However, the questions are how to properly insulate the foundation of a private house and what kind of insulation better fit for this purpose, remains open. The purpose of this article is just to try to understand this issue.

Arguments in favor of insulation:

• frost protection, especially for foundations that are in damp delirium (therefore, it is recommended to insulate the foundation from the outside);
• decrease in the dependence of the foundation base on temperature differences, and consequently, a decrease in deformation;
• expansions-compressions leading to destruction;
• additional waterproofing from ground water and condensate;
• normalization of the microclimate in the house, the ability to use the basement for various needs, so that it is not too cold in winter and warm in summer.

Foundation insulation: types, materials

Depending on the location of the thermal insulation material, the insulation of the foundation can be:

• external, when the material is located on the "facade" of the foundation or, as they say, the basement;
• internal, when the insulation material is located from the inside of the house.

The material used for external insulation must meet certain requirements: have good vapor barrier properties, sound insulation, be inexpensive and have a long service life. Expanded polystyrene, polyurethane foam and a more modern heat insulator - penoplex correspond to these requirements as much as possible.

The use of expanded polystyrene

The technology of insulation with expanded polystyrene is practically no different from the work on thermal insulation of facades and it can be easily done by hand: foam plates are attached to foundation blocks using special glue.

Sometimes mastic is used for this, which performs the functions of additional waterproofing. Dowel-nails are used as additional fasteners.

Note! Not only that part of the foundation, which is located above the ground, is subjected to insulation. Installation of heat-insulating material must also be done in the part that is located underground. To do this, the foundation is dug in, making a trench around it.

Thermal insulation with polystyrene foam has a number of advantages:

• ease of installation of a heat insulator;
• high thermal insulation properties of the material;
• low cost in comparison with other heat insulators.

The disadvantages include the fact that polystyrene foam is often damaged by rodents and it is combustible (this is true when performing insulation from the inside).

Application of polyurethane foam

One of the most effective ways insulation. For its implementation, special equipment is required; it is more difficult to perform such thermal insulation with your own hands.

The technology of work consists in the preliminary preparation of foundation blocks: they are cleaned, dried, chips are removed, and cracks are covered up. Polyurethane foam is applied with a special sprayer, making several layers, which, when hardened, form an even film with excellent thermal and waterproofing properties. The service life of such a heater exceeds 25 years.

The disadvantages of using polyurethane foam as a heater include the high price and the need to use spray equipment.

The use of penoplex

Penoplex is a modern heat-insulating material with a high density. Thanks to the extrusion method of production, foam is saturated with air, which provides it with good thermal insulation and thermal characteristics.

Unlike expanded polystyrene, this material is absolutely harmless; when heated, it does not emit toxic fumes. The material is produced in the form of plates with a thickness of 20 to 60 mm.

Penoplex is fastened to the foundation blocks in two ways and is easily done by hand:

• horizontal, when the material is laid around the perimeter of the house, forming a continuous layer;
• vertical when the plates are mounted on the walls of the blocks.

At correct installation plates are completely absent "cold bridges". Note! All activities for the insulation of the foundation are carried out simultaneously with its waterproofing!

Penoplex is attached to the foundation with a special adhesive for thermal insulation boards. After installation of the plates, it is necessary to seal all the seams using mounting foam. In cold areas, it is recommended to make thermal insulation with foam plastic in two layers.

The advantages of this heater include:

• high density;
• higher rates of thermal insulation in comparison with expanded polystyrene;
• resistance to fungi, rodents.

The disadvantages, in comparison with polystyrene foam, include the cost, the price of this material is much higher, but the quality of insulation is much better.

Internal insulation of the foundation

In addition to external insulation, there is also internal insulation, when the heat-insulating material is attached inside the foundation.

Expanded polystyrene or penolex is used as a heater. The production technology of works completely repeats the thermal insulation of foundation blocks from the outside. Internal thermal insulation helps to make the floor in the house warmer, there will be less dampness in the basement. Such insulation is advisable to do when using basements for household needs.

Conclusion

We briefly reviewed the popular materials for insulating the foundation, and I think we answered the question of how to insulate the foundation in a private house? In fact, all of the listed materials are well suited for these purposes, they differ only in price. Therefore, the choice of material for insulation was not so difficult.

In the past, no one even thought about such an energy-saving measure as warming the foundation of private houses. In this regard, many owners of previously built buildings began to solve this problem as best they could. And often this is done after the walls and roof of the house are insulated, and the desired result is not achieved. This material offers detailed answers to the questions of why it is worth insulating foundations and with what materials it can be done correctly with your own hands.

Why you need to insulate the foundation

In an ordinary private house without thermal insulation, of which a great many have been built, in winter there is almost always a feeling of coolness in the lower zone of the premises. No matter how well the heating system inside a residential building works, this coolness in the legs remains and causes discomfort to the people living in it. You will say - you just need to insulate the floors, and everything will be fine. But in fact, this is not enough, because there are several reasons why it is worthwhile to insulate the foundation:

• as noted above, the loss of heat through the floors causes tangible inconvenience to people;
• the amount of heat lost can be quite significant, which increases the cost of heating a private house;
• the foundation and its above-ground part - the basement without insulation are exposed to moisture and freezing, which contributes to the slow destruction of the structure;
• in areas with heaving soils saturated with moisture, the effect of frost swelling may appear. It exerts an additional load on the base up to its cracking.

If everything is clear with the first paragraph of the list, then the rest require clarification. The fact is that the share of heat losses through cold floors reaches 20% of the total amount of heat lost by the building. Therefore, all attempts to save energy resources by insulating all the structures of the house, except for the base, will not achieve their goal.

Imagine that the cold penetrates inside over the entire area, and the insulation of the floors from the inside does not fundamentally solve the issue, for this it is necessary to insulate the foundation from the outside.

Concrete, from which the vast majority of foundations are made, has a very low resistance to heat transfer. During cold weather, the concrete wall freezes, which causes condensation to form on its inside, which is absorbed into the thickness of the material. When the frost increases, this moisture turns into ice crystals and leads to the destruction of the structure. That is why you should not insulate the foundations of private houses from the inside, this will help protect you from the cold, but will not protect the structural elements from destruction.

The same freezing moisture, with which loess soils are saturated, causes them to swell when frozen, exerting shock loads on the base. As a result, cracks may appear in the concrete, which is at least unpleasant. All of these reasons are equally relevant for all types of houses, including wooden ones, where it is also necessary to insulate the foundation. The exceptions are structures on screw piles, which will be discussed later.

Conclusion. If we analyze all of the above, the answer to the question of whether it is necessary to insulate the foundation or basement of a house without a basement becomes clear. Definitely - yes, it is necessary, and the presence of a basement does not play any role, thermal insulation of the base is always necessary. This is what modern building codes say.

Insulation of the foundation with polystyrene foam and foam plastic

In fact, there are not so many materials suitable for these purposes. A simple rule applies here: the service life of the heat-insulating layer should approach the durability of the structure itself, otherwise the procedure will have to be repeated periodically. It is for this reason that it is better not to use such a popular and cheap foam plastic as a heater for the foundation.

Judge for yourself: the durability of reinforced concrete is at least 100 years, and the foam insulation will crumble in 20-25 years. Despite the fact that the material will be literally buried in the ground, it is not possible to control its condition. The deterioration of the properties of the insulating layer will become noticeable only by sensations and heating costs. Also, the difficulties and cost of re-insulating the foundation should not be discounted, even if it is done by hand and again with inexpensive foam.

The decision to use polystyrene for sheathing the base has the right to life and is even often implemented. But this is a manifestation of short-sightedness and an unfounded approach to business. In extreme cases, the polymer can be used to insulate the part of the foundation protruding above ground level - the basement.

IN modern construction for such work, more suitable polymeric materials are used:

• penoplex (otherwise - penoplex);
• expanded polystyrene extruded.

There is no fundamental difference between these polymers, especially since they are made on the basis of one material - polystyrene. There are differences in foaming technology, but for us they are insignificant. It is important that penoplex and extruded polystyrene foam have high strength and low thermal conductivity, and therefore are well suited for insulating the foundation of a private house. In addition, they practically do not absorb moisture and are very durable.

For reference. These materials have a higher thermal resistance than polystyrene. Therefore, for the thermal insulation of the base, a thinner foam layer is needed (usually 50 mm is taken), which is very convenient. And the strength of expanded polystyrene allows you not to hide it under a brick before filling it with soil in order to protect it from damage.

Thermal insulation under construction

The best way to correctly and reliably insulate the entire foundation with foam plastic is to do it yourself at the stage of building a house. In this case, special bituminous mastic is most often used for gluing polystyrene foam boards to concrete. First, the surface is leveled cement mortar, then cleaned and covered with the first layer of mastic (primer). A rolled waterproofing is glued on it, and a heater is on top. The whole "pie" is shown in the diagram:

As can be seen in the diagram, on top of the heat-insulating layer, you can additionally lay protective covering from geotextiles, although often the foam is simply covered with soil. Additional protection will not require a lot of money, but it will significantly extend the life of the insulation. Details about the technology of insulation of foundations with polystyrene foam using bituminous materials are shown in the video:

Another interesting way to insulate the base of a house without a basement is when the foundation is solid. concrete slab. The essence of the method lies in the fact that expanded polystyrene is laid on a pillow of sand, and a concrete monolithic base is poured on top of it. At the same time, it is possible to immediately lay a heating contour of underfloor heating inside the monolith. This design is called the Swedish plate, a diagram of its device is shown in the figure:

It can be seen here that the Swedish plate refers to shallow foundations, insulated not only from below, but also on the sides. In terms of energy efficiency, this technology is one of the best, but requires a very rigorous approach to work. Failure to comply with technological requirements can lead to cracks in the slab and damage to the underfloor heating system.

The main disadvantage of the Swedish plate is the inability to carry out repairs in case of cracking. But if you lay the insulation of the slab correctly, then such a foundation will quietly stand for several decades. At the same time, the use of a solid slab is possible on various subsiding soils. In practice, this insulated structure is often used to build wooden houses instead of the traditional strip foundation.

Insulation of the foundation of an already built house

In this case, you can not do without dismantling. You will have to remove the lining of the basement and open the old blind area around the building. If the foundation of the house is tape shallow, then it makes sense to get to the bottom of it in order to sheathe the entire surface with heat-insulating material. Another, more popular option is to insulate the basement and lay the penoplex under the blind area in order to prevent freezing of the underground part of the base. The ideal option is to insulate the entire foundation and soil under the blind area, as shown in the diagram:

If you decide not to dig to the ground, then you should still dig a hole at least 1 m wide along the entire wall to a depth of 200-300 mm, and compact the soil. The next steps are:

• clean the surface of the base, remove all sagging, and seal the recesses and cracks with mortar;
• attach with ready-made adhesive mixture polystyrene boards to the plinth. Additionally, fix them with special dowels - umbrellas;
• pour a layer of sand at least 100 mm thick into the pit, level and compact;
• lay out foam or expanded polystyrene slabs by laying geotextiles (as in the diagram);
• fill the blind area and complete the lining of the basement.

How in practice the insulation of the foundation of a built house is carried out, in detail is shown in the video:

Insulation with polyurethane foam

The thermal insulation properties of this material are not inferior to foam, but its application to the surface of a concrete foundation for insulation has its own characteristics. One of them is the need for special equipment, which automatically increases the cost of work. At the same time, polyurethane foam is applied in layers up to 50 mm thick manually, due to which the surface does not turn out to be perfectly even.

This means that the method is good for the underground part of the base, but on the plinth the insulation layer will have to be leveled to make the cladding. What does the plinth look like wooden house with polyurethane foam insulation, clearly visible in the photo:

Before applying thermal insulation to the foundation, a waterproofing device is still required with coating or roll materials. In addition, the width of the trench should be sufficient for the work, that is, at least 0.7 m.

Despite the high efficiency of polyurethane foam as a heater, its application to the foundation is associated with higher financial costs. In addition, there is the question of the durability of the material.

Expanded clay insulation

The main advantage of expanded clay over other materials is durability. The layer of this insulation will last as long as the concrete foundation itself. In addition, the insulation technology is quite simple: expanded clay is simply poured into the cavity between the base with waterproofing and the ground, and a blind area is arranged on top. How to do it correctly is shown in the diagram:

The problem of expanded clay is in thermal conductivity, as a heat-insulating material it is significantly inferior to any modern polymers in this indicator. To verify this, just look at the table, which shows the values ​​​​of thermal conductivity for different heaters:

Note. The lower the thermal conductivity value, the better the thermal insulation properties of the material.

It turns out that in order to create a layer with the same properties of expanded clay, it will be necessary to fill in several times more, which is reflected in the diagram. If it is necessary to insulate the base with it, then you will have to build a retaining wall of facing bricks, which immediately complicates the whole process and leads to a rise in price. In addition, the retaining wall also requires its own foundation or it must be built on the existing one and, again, its underground part should be insulated.

Insulation of a pile-screw foundation

The fundamental difference between this type of foundation is that initially there is a gap between the ground level and the lower part of the building, which can be of different sizes. This is especially noticeable in situations where construction was carried out on a site with uneven terrain or simply on a slope. Accordingly, in most cases, the pile foundation is not insulated as such, the issue is resolved by thermal insulation of the floors of the first floor.

Under certain conditions, the thermal protection of the pile foundation is still performed, for example:

• when the piles are joined together by a single monolithic slab - a grillage;
• if the homeowner decided to arrange a false base and close the gap, thus constructing an underground technical floor with communications passing through it.

Since the grillage is the same concrete slab, it should be insulated using any of the methods described in the previous sections. At the stage of arranging such a foundation, insulating material can be laid under the grillage, as it is proposed to do in the illustration:

In the second case, the gap between the ground and the house is sewn up with any kind of panels or laid with brick or granite, and a blind area is arranged outside. Now, in order to always have a positive temperature in the underground space, the false base must be insulated from the inside with any of the materials listed earlier.

Polyurethane foam spraying is well suited here, since you do not need to dig anything and appearance does not really matter, as reflected in the photo:

Conclusion

As it turned out, the process of warming the foundation is not as simple as it might seem at first. An important point to remember is that heat passes through the heavy concrete of the base very easily, so it needs to be insulated only from the outside. Otherwise, condensation is inevitable. Ideally, the soil under the blind area should also be protected from the cold, then your foundation will never freeze.

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The thermal insulation of the foundation is as important as the thermal insulation of the walls, especially in areas with a harsh climate. Frozen soil cannot protect the foundation of the house from moisture and cold, and the foundation itself, after repeated freezing, begins to collapse faster. To get rid of these problems and reduce the cost of heating your home, you need to know how to insulate the foundation of the house from the outside, and how you can do it on your own.

The foundation of the house is regularly exposed to moisture, increased load, temperature changes. After the onset of frost, the accumulated moisture freezes, destroying the material, and through cracks in the concrete, the cold penetrates into the dwelling. As a result, the floors in the house are always cold, it smells of dampness from under the baseboards, condensation or frost appears on the walls of the basement (in severe frosts). For thermal insulation to be effective, the insulation must have the following characteristics:

• low thermal conductivity;
• water resistance;
• good mechanical strength;
• resistance to temperature changes.

There are no strict requirements for the vapor permeability of the material, but heaters with low vapor permeability are usually used, like the concrete foundation itself. The combustibility of the material is also not of great importance, because the underground part of the building is the least susceptible to fire risks.

Which heater to choose

Mineral wool insulation for foundations is not the best suitable option: they tend to accumulate moisture, while losing thermal insulation properties, and are not sufficiently resistant to mechanical stress. Soil pressure will lead to shrinkage of the material, and the effectiveness of insulation will drop to zero.

Prices for mineral wool

But polymer heaters are devoid of such shortcomings and fully meet the necessary requirements.

Let's consider their characteristics in more detail.

Styrofoam

Expanded polystyrene, or polystyrene, is very widely used in the arrangement of thermal insulation. It is lightweight, its sheets have the correct shape, and therefore it is not a problem to cope with the installation even for a novice master. The material is produced in various densities and thicknesses, and depending on this, it has certain areas of application. Only the most dense sheets with a thickness of at least 50 mm are suitable for foundations, the rest are best used for insulating walls and partitions.

In terms of thermal conductivity, foam plastic is much more efficient than wood, expanded clay, mineral wool insulation. It almost does not absorb water, is not prone to shrinkage and deformation, and serves as an excellent sound insulator. In addition, polystyrene boards fully retain their properties when exposed to salt and chlorinated water, soap solutions, weak acids. The insulation can come into contact with bituminous mastics, lime, adhesive water-soluble solutions and cement plaster.

For slab foundations, as well as deeply buried foundations, it is necessary to use expanded polystyrene marked PSB-S-50, which is able to withstand heavy mechanical loads and provide reliable protection from swelling of the soil. For columnar and standard strip foundations, foam grade PSB-S-35 is used.

All other varieties for foundations are not suitable due to the low density and fragility of the sheets.

Expanded polystyrene, made by extrusion, in all respects significantly exceeds the foam. It is many times stronger, absolutely waterproof, has the lowest rates of vapor permeability and thermal conductivity. Microorganisms do not develop in it either, even under conditions of prolonged exposure to dampness.

Foundation insulation with extruded polystyrene foam - EPS

XPS boards with a smaller thickness have a much greater effect. For thermal insulation of the foundation in a temperate climate, a heater thickness of 40 mm is sufficient, in northern conditions - about 60 mm (two-layer laying of 30 mm thick plates is recommended). For ease of installation and greater packing density, the slabs are equipped with a tongue-and-groove connection.

They are attached to the base with an adhesive solution and dish-shaped dowels.

XPS slabs can be laid vertically (when insulating columnar and strip foundations) and horizontally (when arranging a slab foundation).

Due to its increased strength, the material perfectly transfers the load from the concrete layer, does not flatten out and does not shrink, unlike polystyrene foam and polyurethane foam. The most popular brands of extruded polystyrene foam are Penoplex and TechnoNIKOL.

Main characteristics

Sprayed thermal insulation, or PPU, is increasingly being used in the insulation of foundations. Polyurethane foam forms a very durable seamless coating that is resistant to adverse effects. At the same time, it simultaneously performs the functions of vapor and waterproofing, which greatly simplifies the workflow. Another useful property This insulation is a high adhesion to the base. It adheres equally strongly to stone, concrete, brickwork, wooden structures, easily applied to hard-to-reach areas, fills the smallest gaps.

Polyurethane foam is applied in two ways - pouring and spraying. The first option is more time-consuming and costly, therefore, it is rarely used when insulating private houses. The second method is actively used to insulate the entire building - from the roof to the foundation. Before application, the components are mixed in a foam generator with air and the finished mass is sprayed under pressure onto the work surface. Within a few seconds, the composition hardens, and upon completion of work, you can immediately start finishing. The only disadvantage of such insulation is that it is impossible to do without installation, and these are additional costs.

In addition to the described heaters, bulk materials, in particular expanded clay, can be used for foundations. It is environmentally friendly, inexpensive, has good thermal insulation characteristics, and is suitable for both vertical and horizontal insulation. But since expanded clay can absorb moisture, losing some of its properties, and the workflow requires more effort and time, this insulation is used less and less, yielding to more modern and efficient materials.

Styrofoam prices

Styrofoam

Foundation thermal insulation technology

Insulation of pile, column and strip foundations can be carried out both during the construction process and during the operation of the house. Before installing the insulation, it is necessary to prepare the base, which includes cleaning, sealing cracks, and arranging waterproofing. The better the preparation, the more effective and durable the result. Slab foundations are insulated directly during construction, because heat-insulating slabs are located horizontally under a layer of reinforced concrete.

Strip foundation

The most time-consuming stage in the insulation of such a foundation is earthworks. The foundation must be excavated to its foundation or to the level of soil freezing. If possible, it is better to hire special equipment, because digging by hand will take a lot of time and require a lot of physical effort. The foundation is dug around the entire perimeter to a width of at least 1 m, then the bottom of the trench is rammed and covered with a layer of sand and gravel.

The walls of the foundation are cleaned of the ground with a stiff brush and left open for 10 days so that the moisture evaporates. For this reason, work must be carried out during the warm and dry seasons.

Step 1. Dried walls are carefully inspected for damage, eliminate the identified defects. Cracks before sealing are expanded and cleaned of dust, if necessary, the surface is leveled with cement-sand plaster. If the irregularities exceed 20 mm, the plaster is additionally reinforced with a metal mesh. After plastering, it is necessary to wait for the surface to dry completely.

Step 2 Perform waterproofing of the foundation. It is most convenient to use coating waterproofing, for example, polymer, rubber or bituminous water-soluble mastics. Compositions based on organic solvents cannot be used, since polystyrene foam plates are destroyed upon contact with them.

To improve adhesion, the surface is pre-treated with a bituminous primer, applying it with a thin continuous layer. It takes about a day for the primer to dry, after which you can start applying the mastic.

Step 3 The mastic is stirred, if the mass is too thick, add a little water.

Prices for bituminous mastic

For application use a wide brush with a dense bristle or roller. The composition is evenly distributed over the walls in a continuous layer, very carefully smearing the corners. The layer should not be translucent, but it should not be made too thick so that streaks do not form. The mixture is well rubbed over the surface, filling the smallest pores of the recess. When the first layer hardens, the second one is applied in the same way. Usually two layers are enough, but if the area is often flooded with groundwater, it is recommended to apply 3 layers of mastic.

Step 4 After the waterproofing has dried (after 5-7 days), you can proceed with the installation of foam or XPS. For fixing the plates, a special adhesive is used, for example, ALLFIX, Ceresit CT 83, Titanium.

Installation of insulation is carried out from the bottom up, in horizontal rows, with the obligatory dressing of vertical seams. Apply glue, press the plate to the surface and check its location with a level. When installing the next plate, it is necessary to align the mounting grooves as tightly as possible so that the joints are barely noticeable.

Advice. When laying two-layer heat-insulating boards, the joints of the lower layer must be completely covered by the plates of the upper layer. The combination of joints will lead to the formation of cold bridges, which means that the effect of insulation will be lower than planned.

Step 5 As a rule, the underground part of the insulation does not need additional fixation, because after backfilling the material is tightly pressed against the ground. But in the above-ground part of the slab, it is recommended to strengthen the dowel-nails with wide caps. Fastening is carried out after the adhesive solution has completely dried. To do this, drill in the slabs through holes(in the center of the slab and in the corners) and go deep into the base by 40-50 mm. Next, insert the dowels and hammer them all the way.

Step 6 To protect the surface of the plates from accidental damage, plastering is performed with a reinforcing fiberglass mesh. An adhesive solution is applied to the insulation, distributed in an even layer 40-50 mm thick, a mesh is laid on top and smoothed with a spatula, deepening into the solution. For convenience, the mesh is recommended to be cut into pieces and overlapped by 10 cm.

Step 7 A day later, a fine leveling is performed, and when this layer dries up, the surface is treated with a grater with an emery cloth.

Step 8 Fill the trench with soil, leaving a distance of about 30 cm to the top. The soil is well compacted to reduce shrinkage. A layer of sand 10-15 cm thick is poured on top, which is also carefully rammed, and then a waterproofing membrane and a layer of insulation are laid under a slight slope from the wall. The final stage is the arrangement of the blind area by pouring a concrete screed.

If it is decided to insulate the foundation with polyurethane foam, there is no need for leveling and waterproofing. After digging the trench and cleaning the base from the ground, it is only necessary to eliminate the cracks, as well as remove the delaminations, if any. When the walls of the foundation dry out from moisture, you can start applying PPU. Spraying equipment can be rented from construction company or buy, but if you do not have the skills to work with such equipment, it is better to contact specialists. After the material has hardened, the trench is covered with soil, and a blind area is made on top, as described above.

Column Foundation

Thermal insulation of columnar and pile foundations is performed a little differently. In order to thermally insulate the space between the grillage and the ground, it is necessary to build a pick-up that acts as a base. This design does not bear any load, so there are no special requirements for the mechanical strength of materials.

Step 1. Between the pillars of the foundation they dig a narrow trench up to half a meter deep, a third of it is covered with a layer of sand and fine gravel.

Step 2 A frame of metal rods is laid on top and a layer of concrete mortar is poured.

Step 3 After the concrete has hardened, the space is laid with bricks around the entire perimeter, leaving small ventilation holes in the opposite walls.

Step 4 When the masonry dries, insulation boards are glued on the outside, and then they are plastered using a reinforcing mesh. After the plaster has dried, the trench is covered with soil and compacted.

At the end it is done decorative trim plinth - it can be painting, applying decorative plaster, lining with artificial stone.

Instead of a brick fence, you can install a frame made of timber or a metal profile between the foundation supports. Before installation, the beam must be treated with antiseptic impregnation and dried well. The bars are fastened with metal corners, bolts 65-80 mm long and self-tapping screws, it is preferable to use welding to assemble the metal frame. After installation, the frame is sheathed with EPS or foam boards, and corrugated board or basement panels are attached on top.

slab foundation

With horizontal insulation, the slabs can also be laid in one or two layers. Most often, for slab foundations, a heater with a thickness of 50 or 100 mm is chosen. Thermal insulation is started after the foundation pit is prepared and the sand cushion is backfilled.

Step 1. The sand layer is well compacted over the entire area and leveled horizontally. The smoother the base, the denser the insulation will lie.

Step 2 A film and heat-insulating plates are laid on a sand cushion, joining the mounting grooves. In each subsequent row, the joints are shifted to the width of half the sheet.

Advice. With a two-layer laying of insulation, the lower plates are arranged in rows along the long side of the foundation, and the upper ones along the short side. This will not only eliminate cold bridges, but also further enhance the strength of the heat-insulating layer.

Step 3 A formwork is installed along the perimeter of the foundation close to the slabs, inside which a reinforcing frame of steel bars is mounted. Mix and pour concrete.

Step 4 After the concrete has hardened, a blind area is made. The sand is carefully leveled and compacted with a slight slope from the foundation. The slabs are laid tightly, covered with a waterproofing membrane on top. The membrane sheets are overlapped by 10-15 cm. Then backfilling is performed with sand, again everything is leveled and rammed.

Prices for thermal insulation materials

Thermal insulation materials

Video - How to insulate the foundation of the house from the outside

Video - Insulation of the foundation with polyurethane foam

Video - Insulation of the slab foundation

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. Unique properties expanded clay are enclosed in its porous structure, thanks to which it does not let in moisture and cold, 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 foundations. 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, mineral wool and a film are laid on expanded clay 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 expanded polystyrene close to each other in order to obtain a 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. 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 advantages of the material are 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. The glue is applied pointwise, gradually processing small surface areas. 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 they carry out thermal insulation soil around the perimeter.

High-strength sealed board with PU foam

Polyurethane foam or PPU - modern construction material, which has many advantages. It is characterized by 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?

It occurs by spraying insulation on 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.

Is it necessary to insulate the foundation, and what are the risks of refusing this seemingly unnecessary and expensive procedure? Below, the dangers to which foundation structures are exposed will be considered, as well as an overview of materials for thermal insulation.

Up to 80% of the territory Russian Federation is in recreation heaving soils. Such soil during freezing (seasonal or long-term) is able to increase in volume, which entails a rise in the surface up to 0.35 m. Since the soil freezes with the concrete elements of the foundation, rising, it pulls the structure itself along with it. Several such cycles - and at least the deformation of the structure is ensured.

No matter how reliable the waterproofing is, some moisture will still get into the porous concrete. These drops will be invisible to the human eye, however, under the influence of negative temperatures, wet concrete, as you know, collapses.

It is known for certain that the share of the basement accounts for up to 20% of all heat losses of the building. Unheated basements do not need insulation, they are insulated in the basement area to prevent freezing of the floor boundary between the heated room and the unheated basement.

Advantages in the construction of thermal insulation

So, the above factors are dangerous enough to think about preventing negative temperatures from reaching the foundation. The benefits of thermal insulation are as follows:

1. Levels or significantly reduces the effect of heaving forces on the structure
2. Reduces heat loss and provides energy savings
3. Saves the temperature parameters of the building set by the owner
4. Removes condensation from basement surfaces
5. Protects waterproofing from damage and extends its life

Types of thermal insulation materials for underground structures

In accordance with construction technologies, the following types of heaters are used:

• Styrofoam
• polyurethane foam
• extruded polystyrene foam
• Expanded clay
• Plates based on basalt fibers

Thermal insulation can be carried out both from the inside (in the case of a basement) and from the outside of the foundation. But it should be borne in mind that installation from the inside of the basement will not save the wall from the effects of frost heaving and moisture filling. Internal thermal insulation It is recommended to use in addition to outdoor, in order to reduce heat loss.

The method of working with foam - the pros and cons

Styrofoam is the most common material in the building materials market due to the low cost of production and specifications. It is mounted with an adhesive mixture and dish-shaped dowels, after which it is plastered with a reinforcing mesh. It has low thermal conductivity and is ideal for internal insulation. However, it should be remembered that the foam is hygroscopic, and when performing outdoor work, waterproofing is applied over the plaster. If this condition is violated, in a couple of years such a structure will crumble into constituent balls.

Vertical insulation with polyurethane foam

Polyurethane foam is a relatively new word in thermal insulation technology. Its application requires special equipment and appropriate qualifications. The layer is seamless and without gaps over the entire area of ​​the wall, which completely eliminates the construction of "cold bridges".

Polyurethane foam has high adhesive properties, low thermal conductivity. It also eliminates the need for vapor barrier and waterproofing. The thickness of the layer can be any, the material after application is simply covered with soil. When processing the above-ground part of the basement with polyurethane foam, it must be plastered, as it is destroyed by ultraviolet radiation.

Characteristics and installation of extruded polystyrene foam

This material is a relative of polystyrene, however, due to the closed-cell structure, it has a number of cardinal differences. Possesses high technological characteristics and the increased term of operation. The water absorption index of this material is close to zero, that is, it is a waterproofing along the way.

On the market, extruded polystyrene foam is widely presented in the form of rectangular smooth plates, as well as plates with milled grooves through which the accumulated moisture is drained.

Thus, this material not only provides insulation of the foundation, but also protects the waterproofing from mechanical damage, plus it provides water drainage from the walls in drainage system. Installation begins with the installation of plates to a freezing depth, which is determined for each region separately.

The thickness of the slabs in the corners must be increased by a factor of 1.5 at a distance of 1.5 m in both directions. The plates are fixed with special glue directly to the waterproofing or the bituminous layer is melted at 5-6 points, after which they are strongly pressed. Below ground level, glue is applied at the corners and in the center of the slab, which ensures that the resulting moisture flows off. Gluing starts from the bottom, the second row is mounted with an offset of the vertical joint, the cracks that have arisen during operation are subject to foaming.

When insulating the above-ground part of the basement, additional fixation with dish-shaped dowels will be required at the rate of 5 dowels per plate - in the corners and in the center. Here, the material in question is plastered using a reinforcing mesh.

Exterior insulation technology with expanded clay

The foundation is freed from the soil to the depth of the sole. In this case, the trench must be at least 80 cm wide. Waterproofing is carried out with roofing felt or coating method. Bituminous mastic is just right as an inexpensive material, but quite effective. The surface of the wall is cleaned, all sharp corners, protrusions and irregularities are removed, after which it is treated 1-2 times with a primer.

When installing expanded clay insulation, it is necessary to provide for drainage, especially in those areas where the groundwater level reaches less than 1 meter. Aside from the building, they dig a pit, the depth of which is greater than the depth of the foundation cushion, cover it with geotextile, then a layer of crushed stone, after which pipes with holes 1-2 cm long are laid. Pipes are covered with rubble, then sand.

Expanded clay backfilling begins after drainage and waterproofing are completed. The bottom of the trench is covered with a plastic film, which will prevent moisture from entering the heat insulator. Pour on the ground level and close the blind area.

Thermal insulation of the basement is carried out with a protective brick wall. It is placed in half a brick with dressing at a distance of 30 cm from the base to the height of the entire main wall. Further, the entire foundation, along with backfill and masonry, is covered with roofing material.

Basalt slabs and mineral wool

This type of insulation is not used from the outside due to the low resistance to compression in the underground part of the basement. It can be used for internal insulation, closing the filled frame, for example, with wall plasterboard. Outside, in the aerial part of the basement, it is applicable in the case of subsequent siding.