Insulating the foundation of the house from the outside: the best way to protect the foundation of the building

Thermal protection is an important task that must be performed in order to reliably protect the box from the negative effects of atmospheric forces, and create a favorable microclimate inside the house. Insulation of the foundation of the house from the outside is most often carried out using expanded polystyrene or other insulation. Sometimes a combination of technologies is used for more reliable protection. When choosing a material, it is important to consider all the surrounding conditions.

Insulation of the foundation from the outside allows you to protect the building and create an optimal microclimate inside

Why insulate the basement base from the outside

The basement and foundation are considered the most vulnerable parts of any building, because it is on these structures that the greatest load is imposed on the load-bearing walls and floors. Due to the fact that this part of the house is located below the surface of the earth, it is constantly exposed to moisture and freezing.

It is necessary to insulate the basement in order to maximally protect the house from freezing and moisture

Helpful advice! Insulation of the foundation and the blind area is a task aimed at maximizing the strength and durability of structures, which ultimately determines the service life of the building itself.

The basement is an extension of the foundation that rises above the ground, which then passes into the outer walls of the building. In other words, this part of the building is a connecting element of the foundation and the load-bearing walls, starting from the floor level on the first floor. It is the basement that protects the building from high humidity and cold, and due to the presence of the basement, the house has a more attractive appearance.

First of all, it should be noted that heaters must provide comprehensive thermal insulation for both the basement (basement) walls and the blind area around the building. Otherwise, it would be wrong to talk about the effectiveness of such measures. Theoretically, it is possible to carry out insulation of the foundation from the inside and outside, but the effectiveness of each method will be different.

Internal waterproofing and insulation of the foundation will help isolate the room from the penetration of cold, but in this case, condensation will accumulate in the space between the wall and the insulation, which has a detrimental effect on the walls.In addition, when the basement is insulated from the inside of the house, the basement will not be protected from frost. As a result, cracks may appear and slowly expand, which ultimately will lead to a decrease in the strength characteristics of the building.

The strength and service life of the building will depend on the insulation of the foundation

Insulation of the foundation from the outside allows you to protect the basement and the material from which the basement is made from freezing. The dew point also shifts towards the insulating material, which is considered more resistant to humidity and low temperatures than the base itself. The result of the work is a warm basement and a longer period of operation of the supporting structure. It is better to perform such work during the construction phase. If you do this after the completion of construction, the task will be much more difficult.

Before insulating the foundation of the house, you need to familiarize yourself with the conditions when work may not be needed. For example, if this is a small country house intended for summer use only, you can skip this stage of construction. Other situations where you can neglect the performance of outdoor work and limit yourself only to floor insulation:

• with a low base - up to 0.5 m;
• it is not always necessary to insulate a shallow foundation;
• if the building is located in favorable climatic conditions with no harsh winters.

Insulation of the foundation of the house from the outside: the main advantages

A massive reinforced concrete foundation without thermal insulation from the outside will always be a powerful cooling accumulator in winter, as a result of which the cold will spread to neighboring building structures. It is obvious that the floor level in rooms on the ground floor is usually located above the basement, and the walls and ceilings have their own insulation. However, such proximity always leads to excessive heat losses and, consequently, to additional costs for energy used for heating. Practice shows that the optimal material for insulating the basement base gives up to 20-25% heat savings, regardless of other conditions.

Houses with insulated foundations consume up to 25% less energy for heating than non-insulated buildings

The first important argument in favor of insulating the foundation of a house is to prevent heat leakage from the building. High-quality insulation of basement walls and blind areas around the house significantly reduces (almost to 0 ° C) the effects of winter soil swelling. The reason is simple: near the basement and under the house, the soil simply does not freeze.

All regions have their own indices of soil freezing depth, which depend on climatic characteristics. Below this limit, the temperature is kept relatively constant due to the constant flow of geothermal heat from below. If you do not insulate the foundation of a private house, the base of the walls is not able to stop the spread of soil freezing. As a result, not only the upper part of the foundation itself freezes, but also a strip of earth along the inner part of the tape.

Important! After the foundation of the house has been insulated, the freezing zone does not reach the ground or the walls of the base, which will save them from premature destruction.

All high-quality reinforced concrete foundations are characterized by a certain frost resistance. For example, a properly prepared cement mortar M300 usually has a frost resistance of F200, that is, it can withstand up to 200 freeze-thaw cycles without losing its basic characteristics. However, one should not think that one cycle equals one year. Several dozen such cycles can occur in one season, given the unstable autumn or spring weather. And this, in turn, means that it is best to take measures to avoid exposure to temperature changes on the base, that is, to insulate the foundation of the house.

An insulated building is more frost-resistant, which affects its durability

How to finish the foundation of a private house

If thermal insulation is performed, the freezing zone does not penetrate the house and does not reach the foundation wall. And this gives many advantages at once. The entire height of the strip foundation - from the base to the top of the basement - will be in approximately the same temperature conditions. This means that there will be no strong internal stresses in the reinforced concrete structure, which are often caused by significant thermal disturbances. The lack of insulation of the strip foundation becomes one of the reasons for the rapid deterioration of the building.

How to insulate the foundation? More recently, a mixture of clay and straw was used to insulate the basement, but over the past few decades, technologies have improved. A large number of new thermal insulation materials have been developed, which are characterized by a convenient shape and ease of installation. All modern materials must meet the following requirements:

1. Low thermal conductivity. The lower the coefficient of thermal conductivity, the better the thermal insulation properties of the building material.
2. Low water absorption. Insulation subject to moisture absorption does not fulfill the requirements imposed on it and loses its consumer qualities. This is especially dangerous if the material absorbs moisture in the winter, when freezing water disturbs the structure of the sheets.
3. High compressive strength. The soil puts a lot of pressure on the base, which the insulation must carry without changing its properties.
4. Resistance to exposure to harmful microorganisms. A material subject to the growth of fungus, the appearance of mold, will quickly deteriorate. Also, the sheets of insulation should not be exposed to rodents.

Quite often, expanded clay is used to insulate private houses outside.

The price of basement insulation will depend on the working conditions, on whether the work is performed during construction or already at the stage of its completion. The cost is also influenced by the type of material used, where the main ones are:

• sprayed insulation - polyurethane foam;
• heat-insulating sheets - polystyrene, polystyrene foam, mineral wool, extruded polystyrene foam;
• expanded clay - an inexpensive, bulk type of thermal insulation;
• thermal panels - consist of three layers, including the finishing layer, where plaster or facing tiles are used;
• warm plaster;
• priming.

Insulation of the foundation of the house outside with expanded polystyrene

Warming of the foundation with foam is considered among builders to be one of the most popular methods that prevents the base from freezing. The basement and the foundation are lined with expanded polystyrene plates, which are distinguished by increased density, while the thickness should not be less than 5 cm. Among the main advantages of basement insulation with expanded polystyrene are:

• high thermal insulation qualities and optimal thermal conductivity;
• inability to absorb moisture or collapse under the influence of water due to the closed cellular structure;
• long period of operation - over 50 years;
• good sound and noise insulation properties;
• resistance to fire due to the applied flame retardant;
• the lack of the possibility of mold or fungus growth;
• simple and quick installation of sheets, easy processing and the possibility of self-fixing without the use of special tools;
• low cost of material and its installation.

Expanded polystyrene as a basement insulation has a lot of positive qualities

If we talk about foam, it is worth noting that it has a significant disadvantage - instability in front of rodents, which can damage the sheets. The disadvantages also include a large number of joints between the sheets.Extruded polystyrene foam (penoplex), which is less thick, but more dense, has slightly less negative characteristics.

Insulation of the foundation and blind area of ​​the house outside with expanded polystyrene is more efficient to perform than ordinary foam, due to the locking system of joints, which ensures a more dense arrangement of sheets relative to each other. In addition, the material is less brittle, it does not crumble when cut and can withstand a lot of stress.

Helpful advice! Insulation of the foundation of the house from the outside with penoplex provides a thinner layer of insulation without compromising the ability to retain heat. This makes it possible not to deepen the window openings so much, which will allow more sunlight to penetrate inside.

Extruded polystyrene boards have many different advantages, including lightness, high resistance to heat transfer, ease of processing and installation (including due to the clear geometric shapes of the panels), environmental friendliness, durability and many others.

Expanded polystyrene has excellent thermal conductivity, as well as sound and noise insulation

When insulating the foundation of a house outside with penoplex with your own hands, it is quite easy to calculate the required amount of material, especially if there is a building plan with the parameters necessary for vertical and horizontal basic insulation. The calculation is usually based on the standard dimensions of Penoplex slabs (1200 × 600 mm) and in the range of insulation thicknesses of Penoplex F panels designed specifically for foundations (in ml):

• 20;
• 40;
• 50;
• 60;
• 80;
• 100.

What is foamed polyurethane foam, how it insulates the foundation

Do-it-yourself insulation of the foundation of an already built house has recently become popular to perform using foamed polyurethane foam, characterized by excellent consumer qualities. The only drawback is the need to use a special installation when applying, in which the polyol and isocyanate are mixed under pressure, after which the polymer synthesis begins. During the reaction, carbon dioxide is formed, which creates bubbles that are isolated from each other. Spraying is carried out in a thin layer on a previously cleaned and prepared base.

Before insulating the foundation, it is recommended to familiarize yourself with the positive and negative qualities of the material:

Foamed polyurethane foam is used to insulate already built buildings

1. Excellent thermal insulation properties, which are improved due to the presence of carbon dioxide bubbles, because the thermal conductivity coefficient of foamed polyurethane foam is slightly lower than that of air.
2. Resistant to mold and fungi.
3. Continuity of the applied layer without gaps, joints, cracks or seams.
4. Low weight, which allows you to use the solution on houses with any type of foundation. At the same time, high strength, rigidity and elasticity.
5. Easy repair. If a certain area is damaged, it can be easily cleaned and filled with a new portion of polymer.
6. Fast application. Sprayed insulation is carried out no longer than one day.

In addition to the need to use special tools for application, the disadvantages include the high cost of the material and the inability to independently perform work.

How is mineral wool and warm plaster used to insulate the foundation

Mineral wool is understood as a whole range of building materials, but basalt wool is most often used to insulate a basement or foundation. The initial raw material is rocks, from which thin threads are drawn during the process of heating and melting, which serve as the basis of the insulation. The material is produced in rolls or plates. At the same time, the use of rolled mineral wool allows in the end to obtain a minimum number of seams, but at the same time the plates are distinguished by increased strength.The main advantages of using the material:

Warm plaster has both positive and negative properties

• optimal coefficient of thermal conductivity, provided due to the presence of a fibrous structure;
• good sound insulation;
• low susceptibility to combustion, because minerals are the basis;
• high vapor permeability;
• increased strength and resistance to mechanical damage;
• not susceptible to mold, fungi and rodents.

Using mineral wool, you can easily and quickly insulate the outside of the house foundation with your own hands. Despite the fact that many manufacturers note the material's ability to pass water and not absorb moisture, this is not entirely true. Most of the sheets can accumulate moisture, while the thermal insulation properties are significantly reduced. To avoid this situation, some manufacturers add certain water-repelling substances to the material, but even in this case, it is required to perform reliable waterproofing, which will entail additional installation costs.

Related article:

Insulation of the facade of the house from the outside: the best way to establish a microclimate inside the building

Main advantages. The main types of materials used, their brief characteristics, pros and cons. Styling technologies.

Warm plaster includes dry adhesive mixtures that do not look like cladding material. Most often, the composition of the insulation includes sawdust, vermiculite and expanded polystyrene. The main advantage of the application is the solidity of the heat insulator structure, as well as simple installation. It is allowed to use warm plaster immediately after the preliminary ground layer has dried. If it is not required to apply two layers, then installation can be performed without a reinforcing mesh, which significantly reduces the cost of work. Among the disadvantages are:

• a high level of water absorption, which requires waterproofing;
• a small layer of application, which cannot always provide the proper level of thermal insulation;
• high weight after application;
• the need to cover with a finishing layer.

Mineral wool slabs are characterized by vapor permeability and sound insulation

Use for warming the foundation of expanded clay and thermal panels

Expanded clay is considered a light material with many large granules. The basis of the insulation is fusible clay, which swells and hardens in a drum setting. Expanded clay is a safe and environmentally friendly material with the lowest cost. Suitable for warming the foundation of a wooden house, which is not intended for year-round living. The main advantages of the acquisition:

• good noise and heat insulation due to the porous structure;
• little weight;
• good frost resistance and fire resistance.

The main disadvantage of use is the ability to absorb moisture, which is unacceptable in the conditions of a basement or foundation. In order to solve this problem, good waterproofing is used, drainage is necessarily equipped by digging a ditch deeper than the foundation, at the bottom of which geotextiles are laid. On top of it, medium-sized crushed stone is poured, a pipe with holes is installed through which moisture will be removed.

Then again there are layers of rubble and geotextile, after which everything is covered with sand. After completing the preparatory work, a wooden formwork is mounted to the depth of the foundation and roofing material is laid so that it covers both the walls of the building and the walls of the ditch, while the seams are glued. Expanded clay of a heterogeneous fraction is poured into the formwork, after filling it is closed with a lid, which is installed at an angle of 45 °. This is done in order to protect the base from atmospheric precipitation, including dew.

Thermal panels allow you to save on additional finishing materials

Thermopanels are based on rigid polyurethane foam, the positive properties of which do not differ from foam. The main advantage of using it is the presence of a decorative upper shell that can imitate any material. For the foundation and basement, imitation of stone, brick or tile is most often used. The cost of insulating the foundation with this material varies from 2 thousand rubles per m², but due to the fact that the panels are completely ready for use, you will be able to stick them yourself. Other positive qualities:

• resistance to moisture and good thermal insulation;
• attractive appearance;
• no likelihood of mold.

In addition to the high cost, the disadvantages also include the need to use a high-quality and expensive adhesive, as well as adherence to particular care when gluing. To glue the panels, it is also necessary to have a perfectly flat plinth, or you will have to additionally mount the crate, but the result will be an effectively protected plinth.

Helpful information!In some cases, ordinary sand or earth is used as a temporary material for insulation, with which the basement is covered up to the height of the floor on the first floor. However, you will have to remove the ventilation holes above ground level, and you will not be able to install the windows at all.

Expanded clay is considered the most economically profitable option for warming the foundation

Features of the insulation of the pile foundation, strip and slab base

Thermal insulation of the foundation slab using the technology resembles the implementation of thermal insulation of a concrete floor on the ground. To do this, first of all, soil is rammed, on top of which a geomembrane is laid, which protects the foundation from capillary rise of groundwater. Next are the layers:

• crushed stone-sand cushion, which increases the bearing capacity of the soil and correctly distributes the load;
• roll waterproofing;
• insulation, most often expanded polystyrene or penoplex is used.

There is a wide range of technologies for insulating a strip foundation. Along with the insulation outside the foundation with foam, the technique of permanent formwork, the application of sprayed insulation or expanded clay finishing is used. Mineral wool in this case is rarely used due to its ability to absorb moisture.

If you choose the method of permanent formwork, then it must be planned even at the construction stage, because the thermal insulation materials used to insulate the foundation are an integral part of the structure.

For different foundations, it is advisable to use different types of insulation

It is interesting! When performing non-removable formwork, two issues are simultaneously resolved - insulation of the foundation, both outside and inside.

The formwork is made of various materials, but most often the basement basement is insulated from the outside with penoplex or expanded polystyrene. Before starting work, it is required to make a recess for the blind area from the compacted soil, which is then filled in turn with the following materials:

• rubble;
• sand;
• waterproofing;
• insulation;
• formwork;
• reinforcing layer;
• concrete.

Equally important is the insulation of the base from piles or pillars. Of course, with a properly designed foundation of this type, it is no longer threatened by freezing forces or the destructive effects of soil moisture. However, there are a number of other, no less important issues that can only be solved by creating thermal insulation.

Schematic example of tape-type foundation insulation

Reinforced concrete gratings or post piles require thermal insulation, which must be no less than the base of the strip. It is important to understand that piles are often associated with a monolithic reinforced concrete grating, which without proper insulation becomes a powerful refrigeration element.A characteristic feature of the foundation on piles is the presence of a gap between the ground and the overlap of the first floor, where utilities are usually laid.

Warming of the pile-screw foundation of a wooden house is most often accompanied by decorative finishing of this part of the facade. In any case, the space between the house and the ground will be closed on all sides and will not become a place for the accumulation of dirt or debris. Measures to insulate the pile-screw foundation are also necessary to ensure comfortable living, increase the service life of the building and improve the appearance of the structure.

Foundation insulation technology with foam

This technology can be used with a ready-made foundation, so it can be carried out both during the construction phase and during repairs. If you carry out work after the construction of the building, then you will need to dig out and completely clean the base. After that, it is imperative to create a reliable waterproofing using a bituminous primer, on which strips of overlapping roll materials are then mounted from bottom to top.

Penoplex insulation can be carried out both at the construction stage and on the finished house

After waterproofing is completed, the installation of thermal insulation materials continues. When insulating a foundation covered with waterproofing with your own hands with foam, various methods and materials can be used. It is best to buy a special glue designed for thermal insulation work. The extruded polystyrene foam sheet adheres well to a vertical surface.

Important! Work always starts from the bottom - from the base of the foundation. If the shape of the base is complex, that is, there are several transitions from vertical to horizontal, it is advisable to repeat the entire configuration with insulation. To minimize gaps between the material, it is necessary to stick the sheets as close as possible.

To minimize the possibility of movement of sheets as a result of the pressure of the soil layer, it is imperative to fix the sheets with the use of umbrella dowels when insulating the foundation of a house with penoplex. Holes for fastening are drilled in the base directly through the insulation boards already installed on the adhesive. The diameter and depth of the hole directly depend on the thickness of the insulation, the wall material and the model of the selected dowels.

Penoplex allows you to significantly extend the life of the building

It is usually considered that the expansion part of the dowel enters the foundation wall by 45-60 mm. The number of these elements on a standard plate is 5-6. After the holes are prepared, the dowels are inserted into them so that the caps rest on the insulating panel, and then the expansion gaskets are driven in (depending on the specific model of fasteners). If, based on the results of thermal engineering calculations, it is established that a two-layer insulation is required, then the second row of heat-insulating plates is mounted on the first in such a way that the seams between the blocks are displaced.

At the last stage of the work on warming the basement of the foundation with penoplex, an adhesive solution is applied, then a reinforcing fiberglass mesh is attached, which is then plastered and finished with the selected facing material.

Insulation of the foundation is an important task that helps to extend the life of the foundation, respectively, of the entire building. The choice of insulation and the method of carrying out the work depends not only on the material from which the foundation is made, but also on the surrounding conditions, for example, on the proximity of groundwater, the type of soil and climate. Foundation insulation will be effective only if it is part of the overall “set” of thermal insulation for the recessed foundation, the soil around the building, the ground floor and the façade wall. There should be no gaps between the components of the entire system, otherwise heat will constantly come out.