General information

How to insulate the basement of the house outside


Builders claim that 20% of heat loss is produced through the foundation. Modern technologies allow us to reduce the probability of this negative factor to a minimum.

Warming is done through additional materials that are mounted on the base. When choosing them, it is necessary to take into account not only the price. Equally important are the performance properties, installation method, service life and others.

Why warm the base?

The need for insulation of the basement outside will retain comfortable conditions not only indoors, but also in the basement. Due to this, it will be able to store all vegetables and fruits for a long period of time. Before starting all actions, it is necessary to study the peculiarities of the thermal insulation of the house. The correct approach will save on heating, because resources will not go into the soil.

Basement insulation

At the first stage, a person must learn how to warm the basement of a building.

Allowed to opt for materials that fully meet the following requirements:

  • do not conduct heat inside their surface
  • do not absorb moisture
  • compression is characterized by high strength,
  • the surface is not a favorable environment for the development of microorganisms.

Additionally, it should be noted that the process of warming the basement of a private house should create optimal conditions for a long period of time. Equally important is environmental safety.

It is necessary to warm the foundation and basement from the inside and outside. The choice of option depends on the climatic conditions and the material from which the walls and the foundation are made.

Insulation outside

On the preservation of heat in the room should take care before the onset of cold weather. To do this, the house should be insulated outside with their own hands. Sufficient attention should be paid to the choice of material. It can be in the form of a plate or on a polymer base. Before buying should consider the advantages, disadvantages and method of installation.

Polyurethane foam

If you are thinking about how to insulate the basement of the house quickly and efficiently, then attention should be paid to this material.

It has the following advantages:

  • quick installation
  • low weight
  • high inertness and durability of the coating,
  • monolithic insulation,
  • long service life
  • high adhesion
  • the material does not burn and does not become covered with mold,
  • convenience and versatility coverage.

Among the shortcomings should be noted the presence of a negative reaction to ultraviolet. During installation, special equipment must be used. It makes it possible to distribute polyurethane over the surface of the base.

Heat insulation cake will be high only if the material covers the foundation without gaps. Additionally, it should be noted that there is no need for preparatory work.


This insulation is an effective modern heat insulator. It is also called foam plastic or advanced foam plastic. There are several types of polystyrene - extruded and foamed. Between themselves, they differ in production technology and quality.

Specialists in the construction industry tend to use extruded polystyrene. It costs more than foamed, but has many advantages:

  • low heat transfer coefficient
  • strength,
  • environmental friendliness
  • moisture resistance,
  • durability.
Expanded polystyrene is also used for basement insulation, but in this case concrete is waterproofed with bitumen mastic.

The advantages of polystyrene, compared with other types of insulation, are:

  • lower cost
  • a special structure that does not absorb and does not pass moisture, which preserves the integrity of the plates at low temperatures,
  • long service life
  • preservation of heat-insulating properties throughout the entire period of operation,
  • "Inedibility" for rodents,
  • simplicity of installation of insulating designs.
The disadvantages of polystyrene include:
  • the ability to release very dangerous toxic substances in case of fire,
  • vapor permeability, due to which mold and fungus can develop, destructive structures and adversely affect the indoor climate.

Penoplex - a new progressive insulation that is very effective in terms of heat retention. For the manufacture of penoplex high pressure and temperature are applied, which affect the granules of the material, they are inflated and filled with air. The resulting material is characterized by a finely porous structure, which has the same tiny isolated cells, which allows you to retain heat well.

The advantages of Penoplex include:

  • long service life
  • low thermal conductivity
  • minimum moisture permeability
  • compressive strength
  • simplicity and convenience of processing and installation,
  • environmental friendliness
  • low chemical activity
  • maximum biostability, which implies resistance to rotting and decomposition of the material.

Despite the many advantages of Penoplex, it has one serious drawback - the ability to melt and ignite if the recommended temperatures are not followed.

Polyfoam is a special foam material, the granules of which are 98% air. Polyfoam is characterized by good thermal insulation properties, therefore, it was previously actively used for insulation of premises.

The advantages of using foam for insulation include:

  • material cheapness
  • durability,
  • low thermal conductivity
  • simplicity in processing and installation,
  • high speed work.

The disadvantages of foam include:

  • fragility
  • the need for additional ventilation,
  • ability to absorb moisture
  • release of toxic substances during combustion,
  • propensity to freeze in the period of severe frosts and the possibility of damage from direct sunlight on the material.

Digging the base around the perimeter

Before proceeding to the weatherization of the basement of the foundation, it is necessary to dig out the foundation to the ground. For this, a trench is being dug around the perimeter. The optimum trench width should be at least 1 meter.

If a new house is being built, the procedure is simplified, since there is no need to dig in the foundation - its insulation is made immediately after construction.

Surface preparation

That part of the foundation, which was under the ground, as well as the part that was above the ground, is cleaned of dirt and pieces of concrete. To do this, you can use a spray or high pressure washer. If you do not have such devices, you can use a regular brush and walk it over the entire surface, carefully cleaning the foundation.

Performing drainage

If there is a risk of underflooding of the foundation and groundwater coming close to the soil surface, it is necessary to drain. For this, the bottom of the trench is covered with sand, and geotextiles are laid on top, over which a layer of gravel is poured.

On the gravel is placed a perforated pipe, the end of which must be led to the collector. The pipe is wrapped with geotextile and covered with a mixture of sand and gravel.

Plaster base coating with primer

The dried walls of the basement basement are coated with a latex-based primer. This tool will allow to fill all the cracks and pores that are on the surface, and provide better adhesion of the waterproofing to the foundation.

Laying self-adhesive waterproofing

A layer of waterproofing is needed to prevent moisture from entering the concrete surface. Polyurea can be used as a waterproofing material - it is applied in a liquid form, resulting in a thin and durable elastic membrane.

In the absence of mechanical effects on the membrane, such waterproofing protection will last more than 30 years. If the film is damaged, this place is treated with a small amount of polymer - after that the damage site will not affect the solidity of the layer.

It is also very often that liquid rubber is used as a waterproofing material - it is characterized by a shorter service life than polyurea, but costs much less. Such a tool can be purchased already in finished form. For use, it is simply mixed and applied to the surface with a spatula.

Video: foundation waterproofing

As an alternative to liquid waterproofing substances, a bitumen-based roll material is used, it is attached with a burner, heating the material to 50 ° C, and applied to the foundation. To glue such material is necessary in the direction from the bottom up.

There are also materials (for example, "TECHNONICOL") that do not require the use of high temperatures. After applying the bitumen primer to the surface and removing the protective film, the sheets of material are simply pressed to the surface and adhere to it. The upper edge of the insulation is fixed with a special rail.

Fixing sheets of insulation

Before starting to warm the foundation, it is necessary to mark with the help of the level the bottom line to which the plates will be attached. It is necessary to lay insulation materials starting from the corner of the foundation.

To avoid the formation of long vertical seams, you can make gluing sheets in a checkerboard pattern. Initially, the insulation is placed on the lower part of the foundation, then the rest of the rows are put upwards. For fixing use a special glue, which is applied on the edge and in the center of the sheet. After applying the adhesive, you need to wait a minute and proceed to gluing the sheets to the foundation.

To do this, they are well pressed to the surface and fixed on it for a few seconds. Drying of the glue occurs gradually, so if you find any errors or unevenly placed insulation, you can fix it by simply turning the sheets at the desired angle.

If you need to attach another layer of insulation, it is placed in a checkerboard pattern so that the upper layer overlaps the seam of the lower layer - this will contribute to better thermal insulation. Gluing the top layer does not differ in technology from attaching the bottom layer of insulation.

That part of the foundation, which will be below the ground level, does not require additional fastening - after the completion of the installation work, it is simply covered with earth. The part that will not be powdered must be attached with special dowels. They are characterized by a wide plastic perforated cap, due to which the insulation is pressed tightly against the wall. To attach the dowels in the insulation, the through holes are drilled in such a way that they enter the concrete by 4 cm, after which they plug in the dowels.

Sealing gaps

When the installation of insulation is fully completed, the seams should be treated for better insulation of the insulation. To do this, use a bituminous composition or conventional mounting foam.

The process of sealing seams is quite simple and consists in processing the chosen means of the butt sections of insulation. If a bituminous compound is used, they fill the slots flush. When using foam, after it is completely dried, all irregularities are flush flush.


To protect the insulation from the chemical effects of moisture, which is constantly in the ground, reinforcing fiberglass mesh is fixed on the walls and plastered with a thin layer of solution for coating waterproofing.

Video: basement (basement) insulation with their own hands

Formwork under the blind area

To perform the formwork, it is necessary to determine the width of the blind area. It can be from 70 cm to 2 m and depends on the characteristics of the soil. If the trench was covered with sand and gravel, it is recommended to make a blind area 1 m wide. The formwork for the concrete blind area will prevent the spreading of the concrete solution and determine the geometry.

A mixture of gravel and sand should be leveled as much as possible with a rake, using a level so that the formwork is level. Further, on the width chosen by you, along the entire perimeter of the foundation, pegs are hammered into the ground. In front of them, flat wooden planks are mounted on the edge and fastened together, so that an empty frame is obtained.

After the frame is made, it is necessary to make expansion joints to prevent cracking of the concrete at low temperatures. For this, boards of 2 cm in thickness are suitable - they are mounted on an edge perpendicular to the foundation and formwork frame, the distance between them should be about 2 m. In the corners of the board are installed diagonally from the corner of the foundation to the corner of the formwork. Considering that the main purpose of the blind area is to protect the foundation from water during rains and snowfalls, it must be done with a slope, for this board are installed at a slight angle from the building to the edge of the formwork.

It is recommended to tilt from 2% to 10%, the recommended figure is 5%. Due to this difference, the water will quickly move away from the wall of the building. Before attaching the compensation boards to the formwork frame, check that they have the same angle of inclination using a level.

When the formwork frame is ready, it is necessary to proceed with the installation of waterproofing materials and insulation, as well as a reinforcing mesh, the cell size of which should be 10 by 10 cm.

Concrete Pouring

After all the steps for preparing the formwork are completed, you can start pouring concrete. It can be purchased at a concrete plant or in any specialty store. Be sure to make sure that it is of high quality.

If you plan to save and make concrete yourself, for this you need to use cement (1 part), sand (2 parts) and crushed stone (3 parts):

  1. Initially, a little water and cement are added to the mixer to get a very fluid mass.
  2. Then a little rubble is poured.
  3. All components are mixed for 3 minutes.
  4. At the final stage, sand is added to the mixer.

Often, the compensation boards remain in the formwork, but it is worth remembering that the tree is able to quickly absorb moisture and expand, and shrink after drying, which leads to cracking of the blind area.

Therefore, after the concrete has been poured in and has not fully grasped, it is necessary to remove the compensation boards and wait for the solution to completely dry. After the concrete is completely dry, the cavities left over from the compensation boards are filled with mastic or liquid rubber.

Above the finished paving after full drying of concrete and mastic tile is laid or other material - depending on personal preferences.


More recently, in the 80s of the last century, the payment of utilities accounted for only 3-4% of the total family income. Today, the share of a communal flat on average already reaches 10-15% of family income, and the payment for heating - 30% of this amount. It is not surprising that the majority of Russian citizens prefer to closely monitor costs, and especially for heat leaks in their homes. It has been established that about 20% of heat losses fall on the plinth and foundation, therefore the insulation of the plinth of the house is as important and necessary as the insulation of the walls. Properly performed insulation will not only save the expensive heat, but also to avoid moisture condensation on the walls of the basement, the formation and development of mold, as well as protect the structure from freezing.

№2. Is it necessary to warm the basement of the house?

The peculiarity of the national mentality is that I want to save on everything. Hence the popular question: Is it always necessary to warm the basement of a private house? Insulation may not really be needed in such cases:

  • if the house is intended only for summer living,
  • if there is no basement in the house, and the basement is small (0.5 m) and is arranged to avoid flooding,
  • if the house is located in an area where there is no harsh winter.

In all these cases, you can get insulated floor. If the climate in the region is harsh, the house is used for permanent residence, and it is supposed to store food in the basement, to arrange a garage, boiler room or other utility rooms, then we cannot do without warming.

Number 3. Materials for basement insulation

In the recent past, a mixture of clay and straw was used to warm the basement plinth. Over the past few decades there have been many new, more advanced and convenient ways to perform thermal insulation. A series of advances requirements:

  • low thermal conductivity. Insulating properties are better for those building materials that have a lower thermal conductivity coefficient,
  • low water absorption. When the insulation absorbs moisture, it loses some of the important performance characteristics. The accumulation of moisture is especially dangerous during the frost period, when water increases in volume and can disrupt the structure of the insulation,
  • high compressive strengthbecause the material must withstand the pressure of the soil.

In addition, the insulation should be durable, vapor-permeable, resistant to mold and rodents.

Today, the following materials are used for insulation:

  • теплоизоляционные плиты (пенопласт, экструдированный пенополистирол, минеральная вата),
  • пенополиуретан, который наносится благодаря напылению,
  • керамзит – самый популярный вариант насыпной теплоизоляции,
  • warm plaster
  • thermopanels,
  • priming.