What is the best way to insulate the foundation of a house from the outside. Insulating the foundation of a house from the outside How to insulate the foundation from the outside with your own hands

Insulating the foundation from the outside is a necessary measure for houses located in regions with a less than warm climate. It is even more important to insulate the foundation if the house has a residential basement or utility rooms in the basement. Foundation insulation solves two main problems:

• energy saving
• protection of foundation structures.

In the climate of central Russia, it is necessary to insulate the foundation. In winter, a lot of heat escapes through the floor, and an uninsulated basement or foundation significantly increases heating costs. If you plan to create a warm room in the basement, such as a garage or a basement floor, then you can’t do without high-quality insulation. But even if the subfloor is simply used for storage, a cold floor does not contribute to more comfortable conditions in the house.

The second task that insulation of the foundation solves is its protection from destruction. During the winter, several cycles of defrosting and freezing occur, which means that water turns into ice and back into liquid several times. Getting into cracks and pores in concrete and freezing, it gradually destroys it. In addition, without thermal insulation, condensation forms on the foundation, the concrete becomes wetter, under such conditions it ages faster, which means it will begin to deteriorate faster. It should be remembered that any material is designed for a certain number of defrost-freeze cycles, so without insulation it will last much less.

Insulating the foundation of a house from the outside helps protect it from frost heaving of the soil. If the building stands on heaving soil, not only the walls, but also the main foundation slab are insulated. Thanks to thermal insulation, the foundation will be protected from the destructive effects of ground movement.

Thermal and waterproofing of the foundation should be carried out as soon as it is ready.

Materials for foundation insulation

• Styrofoam
• Expanded clay
• Liquid polyurethane
• Extruded polystyrene

All materials for insulating the foundation from the outside can be divided into two groups:

• slab
• for backfilling.

Backfill materials include expanded clay, slag, straw and other similar materials. This method of thermal insulation has been used for a very long time. At the moment, expanded clay is considered the most effective. This is a cheap material, but insulating the foundation using it requires a lot of labor, and if you hire workers, even money.

It would be rational to use expanded clay not as the main insulation, but as an additional insulation. For an effective heat-insulating layer of expanded clay, a lot is required - its layer must be equal to the freezing depth of the soil plus 5 cm. In central Russia this is approximately 155 cm. To insulate with expanded clay, they dig up the foundation to the very base and dig a trench of the appropriate width.

Liquid polyurethane

Liquid polyurethane has many advantages:

• high adhesion to the surface,
• can be applied to the surface without preparation,
• no seams,
• excellent moisture resistance,
• at the same time it is waterproofing,
• low vapor permeability,
• service life more than 40 years,
• environmental cleanliness,
• biological neutrality - mold, fungi, and moss do not grow on it.

The disadvantage of this material is that to apply it you need to invite a specialist or buy special equipment, so the cost of the work is quite high. Another disadvantage is that it is destroyed by ultraviolet radiation, but for a foundation located underground, this does not matter.

Styrofoam

Polystyrene foam is a type of polystyrene. Its use as insulation when insulating a foundation with your own hands is considered optimal for several reasons.

• Polystyrene foam is a cheap material.
• It does not absorb water.
• Durable.
• Does not change shape over time.
• It has very low thermal conductivity due to its high air content.
• Resistant to temperature changes.

Effective insulation with foam plastic from the outside is impossible without calculating its thickness. It depends on the purpose for which the foundation of the house is insulated, and whether it is planned to create a heated basement. The thickness of the foam can be calculated based on the fact that 50 mm of foam retains heat in the same way as 250 mm of brick (a wall of one brick). For thermal insulation of the foundation, dense foam plastic of the PPT-25 and PPT-35 brands is used.

Important! When purchasing polystyrene foam, pay attention to its quality. Color and geometry are important here. Properly stored polystyrene foam is white, a grayish or yellowish tint indicates that the material has been exposed to ultraviolet radiation and the top layer has begun to decompose. The size of the sheets should differ by no more than 1 cm, otherwise they will have to be adjusted on site.

Extruded polystyrene (expanded polystyrene, penoplex)

Now extruded polystyrene (expanded polystyrene) is considered the most effective slab material for independent installation of thermal insulation of the foundation. It has lower thermal conductivity than polystyrene foam, is somewhat more expensive and has vapor permeability. Typically, expanded polystyrene sheets have a convenient tongue-and-groove joint.

Insulation of the foundation with polystyrene foam or polystyrene foam

Insulation of the foundation from the outside with foam plastic or penoplex is carried out using the same technology. The thickness of the material should be approximately:

• for southern regions - 50 mm,
• for the middle zone - 50-100 mm,
• for northern regions - 100-150 mm.

The foundation must be excavated to the very foundation. The concrete is cleaned of soil and destroyed parts, and if necessary, the surface is leveled with a cement-sand mixture. Then bitumen or special mastic is applied to it for waterproofing. You can use rolled materials (roofing felt).

It is advisable at the same time to think through and make drainage to drain water from the foundation. To do this, you need a drainage pipe, which is placed below the base of the foundation or basement floor. A bed of gravel is poured with a slope of 5 degrees from the building, a pipe wrapped in geotextile is placed on it and covered with gravel.

The sheets are glued with glue or adhesive foam. It is better to choose the latter in packages for a gun, as it is more convenient to apply and costs less. If it is necessary to cover the foundation with penoplex in two layers, the sheets are placed in a checkerboard pattern so that cold bridges do not form at the seams. The next layer can be glued only after the glue under the previous one has completely dried.

Important! Do not use solvent-based adhesives that can degrade foam. Hot mixtures, which can melt the material, are also not recommended.

A reinforcing mesh is glued to the parts of the insulation protruding above the ground. To do this, apply a layer of glue to the insulation and embed the mesh into it.

Thermal insulation of a pile-screw foundation

The design of a house on a pile-screw foundation assumes that between the floor and the ground there is an air space where cold air can freely pass, so insulation in such a house cannot be avoided.

Insulation of a pile foundation is done using the following materials:

• foam plastic,
• penoplex,
• extruded polystyrene foam,
• foam glass,
• expanded clay.

Even during the process of building a house, you need to think about waterproofing the grillage. Rolled waterproofing material is laid between it and the lower part of the walls. The grillage is also treated with waterproofing compounds, especially if it is wooden. The piles are treated with mastic to protect them from corrosion.

The simplest and cheapest method is to fill the foundation with soil or expanded clay, but this does not give the best results; use it only if you are very strapped for money.

If the house is located low above the ground, you can build a basement and insulate it from the outside. The most effective option is complete insulation, when the floor is thermally insulated from the outside and an imitation of the base is arranged.

Floor insulation

You can only insulate the floor from the outside - this method is chosen when the house is located high.

• A vapor barrier film is attached to the floor below.
• Slab insulation, for example, polystyrene foam, is attached to the top.
• Thermal insulation is covered with boards.

Base insulation

The plinth can be made by building a thin brick wall or by installing plinth panel guides. When constructing the walls, a small concrete strip is poured, which itself acts as thermal insulation.

If the method of fastening the guides is chosen, then they are bolted or welded to the piles. Then the decorative material is installed in accordance with the technology.

Such a base can be insulated inside or outside with polystyrene foam. You can mount DSP boards from the outside, or you can attach the finishing material directly to the insulation. To protect against rodents, a metal mesh is attached to the insulation layer. If the base is concrete or brick, then first cover up all the cracks and prime the wall. To completely eliminate blowing, additional expanded clay or soil is added from the inside.

Base thermal panels can be used as both a decorative material and insulation. They are made on the basis of polystyrene foam and have a decorative coating and a convenient joining method.

The foundation of any structure can serve not only as a support and foundation for the building. It can also perform quite utilitarian functions and serve as walls for habitable premises located on the semi-basement and ground floors.

Creating a useful volume inside the perimeter of the foundation (living space) is possible, as a rule, by laying a continuous strip foundation. The foundation is in the form of a concrete monolithic slab, usually does not involve the construction of basements. In principle, it is possible to build a room inside a columnar foundation, but you will still have to equip the outer perimeter walls for this.

In order to build a habitable room inside the perimeter of the foundation - foundation walls need to be insulated. In the vast majority of cases, strip foundations are made of concrete (both from ready-made blocks and from self-formed concrete castings), and this material has very poor thermal insulation properties. In order for a person to feel comfortable in such a room, it is necessary to carry out thermal insulation work.

During the process of building a house, it is necessary to take care of insulating not only the walls and roof, but also the base of the foundation, so that the future housing will be as warm as possible and inexpensive during the heating season. Today we will take a detailed look at the steps to insulate the basement of a building from the outside, and also find out which insulation is best suited for these purposes.

Material selection

Before you begin the process of insulating the foundation plinth, you need to select the appropriate material. There are many insulation materials, but among the most popular are polystyrene, penoplex and polystyrene foam. Let's look at how they differ and which one is better.

Did you know? Penoplex was invented in the USA in 1941, but in the post-Soviet space they began to use it as insulation only in the late 90s.

This insulation is an effective modern heat insulator. It is also called polystyrene foam or advanced foam. There are several types of polystyrene - extruded and foamed. They differ from each other in production technology and quality.

Construction specialists are inclined to use extruded polystyrene.
It costs more than foam, but has many advantages:

• low heat transfer coefficient;
• strength;
• environmental friendliness;
• resistance to moisture;
• durability.

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

• lower cost;
• a special structure that does not absorb or allow moisture to pass through, which preserves the integrity of the slabs at low temperatures;
• long service life;
• preservation of thermal insulation properties throughout the entire period of operation;
• “inedible” for rodents;
• ease of installation of insulating structures.

• the ability to release very dangerous toxic substances in the event of fire;
• vapor permeability, as a result of which mold and mildew can develop, destroying structures and adversely affecting the microclimate in the room.

Did you know? Polystyrene foam was invented by the German pharmacist Eduard Simon in 1839. But they began to actively use it on an industrial scale only in the middle of the 20th century.

Penoplex is a new progressive insulation material that is very effective in terms of heat retention. To produce penoplex, high pressure and temperature are used, which act on the granules of the material, they are inflated and filled with air.
The resulting material is characterized by a fine-porous structure, which has identical tiny insulated cells, which allows for good heat retention.

The advantages of penoplex include:

• long service life;
• low thermal conductivity coefficient;
• minimal moisture permeability;
• compressive strength;
• simplicity and ease 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 disadvantage - the ability to melt and ignite if the recommended temperatures are not observed.

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

The advantages of using polystyrene foam for insulation include:

• cheapness of the material;
• durability;
• low thermal conductivity;
• ease of processing and installation;
• high speed.

The disadvantages of polystyrene foam include:

• fragility;
• the need to provide additional ventilation;
• ability to absorb moisture;
• release of toxic substances during combustion;
• tendency to freeze during severe frosts and the possibility of damage from direct sunlight on the material.

Excavation of the foundation around the perimeter

Before you begin insulating the foundation base, you need to dig out the foundation to the ground. To do this, a trench is dug around the entire perimeter. The optimal 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 carried out immediately after construction.

Surface preparation

The section of the foundation that was underground, as well as the part that was above the ground, is cleaned of dirt and pieces of concrete. You can use a spray bottle or a pressure washer to do this. If you do not have such devices, you can use a regular brush and walk it over the entire surface, thoroughly cleaning the foundation.

Important! When using water to clean the foundation, it is necessary to dry the surface; to do this, work should be suspended for several days.

Performing drainage

If there is a risk of foundation flooding and groundwater comes close to the soil surface, drainage must be done. To do this, the bottom of the trench is covered with sand, and geotextiles are laid on top, on top of which a layer of gravel is poured.

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

The dried walls of the foundation plinth are coated with a latex-based primer. This product will 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 necessary to prevent moisture from entering the concrete surface. Polyurea can be used as waterproofing - it is applied in liquid form, resulting in the formation of a thin and durable elastic membrane.

Provided there are no mechanical impacts 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 this, the place of damage will not affect the solidity of the layer in any way.

Liquid rubber is also very often used as waterproofing - it has a shorter service life than polyurea, but is much cheaper. This product can be purchased ready-made. To use it, simply mix it and apply it to the surface with a spatula.

Video: foundation waterproofing

As an alternative to liquid waterproofing substances, roll material based on bitumen is used; it is attached using a burner, heating the material to 50°C, and applied to the foundation. This material must be glued from bottom to top.

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

Before you start insulating the foundation, you need to use a level to mark the bottom line to which the slabs will be attached. It is necessary to lay insulating materials starting from the corner of the foundation.

To avoid the formation of long vertical seams, you can glue the sheets in a checkerboard pattern. Initially, the insulation is laid on the lower part of the foundation, then the remaining rows are laid from bottom to top.
For fastening, a special glue is used, which is applied to the edge and in the center of the sheet. After applying the glue, you need to wait a minute and begin gluing the sheets to the foundation.

Important! The glue should not contain traces of organic solvent, which can have a destructive effect on the insulation.

To do this, they are pressed well against the surface and fixed on it for a few seconds. The glue dries gradually, so if you find any errors or have placed the insulation unevenly, you can correct it by simply turning the sheets at the required angle.

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

The part of the foundation that will be below ground level does not require additional fastening - after installation work is completed, it is simply covered with earth. The part that will not be sprinkled must be attached with special dowels.
They are characterized by a wide plastic perforated cap, thanks to which the insulation is pressed tightly against the wall. To attach the dowels, through holes are drilled in the insulation so that they extend 4 cm into the concrete, after which the dowels are driven in.

Important! The size of the dowel is selected in accordance with the thickness and number of layers of insulation.

When the installation of insulation is completely completed, the seams should be treated for better sealing of the insulation. To do this, use a bituminous composition or ordinary polyurethane foam.

The process of sealing seams is quite simple and consists of treating the joint sections of the insulation with the selected product. If a bitumen compound is used, it is used to fill the cracks flush. When using foam, after it has completely dried, cut off all irregularities flush.

Backfilling the trench

After filling the gaps, you can begin backfilling the trench. To do this, use coarse dry sand, which is used to fill the bottom layer of the trench. After this, gravel mixed with sand is poured over the sand. A gravel cushion will be a good base for insulating the soil layer.

Plastering

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

Video: do-it-yourself insulation of the foundation (basement)

Execution of formwork for the blind area

To perform 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 filled with sand and gravel, it is recommended to make the blind area 1 m wide. The formwork for the concrete blind area will prevent the concrete solution from spreading and will determine the geometry.

The mixture of gravel and sand must be leveled as much as possible with a rake, using a level, so that the formwork is level. Next, at the width you choose, around the entire perimeter of the foundation, pegs are driven into the ground. In front of them, smooth wooden boards are placed on edge and fastened together to form an empty frame.

After the frame is made, expansion joints must be made to prevent concrete from cracking at low temperatures. For this, boards 2 cm thick are suitable - they are installed on the edge perpendicular to the foundation and the formwork frame, the distance between them should be about 2 m.
In the corners, the boards 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, the boards are installed at a slight angle from the building to the edge of the formwork.

Important! For fastening, use self-tapping screws so that it is convenient to remove them later.

It is recommended to tilt from 2% to 10%; the recommended rate is 5%. Thanks to this difference, the water will quickly move away from the wall of the building. Before attaching expansion 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 begin laying waterproofing materials and insulation, as well as reinforcing mesh, the cell size of which should be 10 by 10 cm.

Video: do-it-yourself blind area around the house

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

If you plan to save money 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 concrete mixer to obtain a very liquid mass.
2. Then the crushed stone is gradually poured out.
3. All components are mixed for 3 minutes.
4. At the final stage, sand is added to the concrete mixer.

Important! For the production of concreteCan start on your own only if you have previously had such experience, since there is a clear technology and many nuances, if not followed, the concrete may crack and will not last long.

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

Therefore, after the concrete is poured and has not completely set, you need to remove the compensation boards and wait until the solution dries completely. After the concrete has completely dried, the cavities that remain from the compensation boards are filled with mastic or liquid rubber.

After the concrete and mastic have completely dried, tiles or other material are laid on top of the finished blind area, depending on personal preferences.

Finishing the foundation

After the plaster has completely dried, you can begin finishing the foundation. For this purpose, decorative materials in the form of artificial stone or tiles are used. You can limit yourself to painting with bitumen or regular paint.

Video: finishing the base with your own hands

Thus, insulating the foundation base with your own hands is a rather labor-intensive and difficult process. However, if you follow all the recommendations and follow the order of work, you can get a good result that will keep your home warm and cozy for a long time.

When building a house, it is important not to forget to insulate the foundation. Some will say that there is no need to do this. But if you do not protect the base with insulation, then in the first winter the owner will notice that the rooms quickly cool down, the floors are cold and an unpleasant dampness appears. This is all due to the fact that frozen soil gradually destroys the foundation, and the cold penetrates into the rooms.

Under the influence of low temperatures, the soil begins to move, which is why small cracks appear in the material from which the foundation is made. Groundwater enters such pores and, freezing, expands them, which leads to the gradual destruction of the base.

To avoid such consequences, the foundation is insulated during the construction stage. You can install insulating material after the house has been in use for some time. In order for the thermal insulation layer to last for a long time, it is covered with finishing materials. This design serves as a barrier against the effects of:

1. Moisture.
2. Temperature changes.
3. Mechanical type.

In addition, thermal insulation retains heat indoors, which means you can spend less on heating your home and still have a pleasant microclimate.

Requirements for insulation

The foundation is the part of the building that is always subject to loads, which is why increased demands are placed on materials for finishing or insulation. When choosing a thermal insulation coating, pay attention to:

1. Ability to withstand temperature fluctuations.
2. Thermal conductivity - the minimum values ​​are selected.
3. Moisture-repellent properties - the material should not absorb water at all.
4. Mechanical strength.
5. Vapor permeability is not particularly important for the base, but it is better to select a material with indicators similar to the one from which the foundation is made.

Fire safety is not the main criterion for choosing insulation, since the material will be hidden under a layer of soil and finishing.

Which foundation insulation to choose?

Natural materials, such as mineral wool, are not usually used for foundation insulation. The insulation quickly absorbs and accumulates moisture, and shrinks under the mechanical influence of the soil. All this leads to the fact that thermal insulation cannot perform its intended functions.

A good option for such work would be to use synthetic insulation. For example,

1. Expanded polystyrene.
2. Extruded polystyrene foam.
3. Polyurethane foam.

Expanded polystyrene

This material is often used not only as insulation for facade walls, but also for foundations. The base is covered with polystyrene slabs with high densities and a thickness of at least 5 cm. The main advantages are called:

• Light weight, which simplifies transportation and installation.
• The rectangular shape allows both an experienced craftsman and a beginner in this field to quickly and efficiently complete the installation process.
• Low thermal conductivity.
• Soundproofing properties.
• Chemical and biological inertness.
• Moisture-repellent properties.

Extruded polystyrene foam

This is the closest relative of polystyrene foam. During the manufacturing process, another stage is added - extrusion, which gives the insulation improved characteristics. Therefore, extruded polystyrene foam differs from polystyrene foam:

• Greater density for the same slab thickness, which means that it can be used less under equal conditions.
• Absolute impermeability to steam and moisture.
• Increased strength characteristics.
• Possibility to install slabs vertically and horizontally.
• Biological inertia.

Builders call this one, but this is just one of the brands that produces extruded polystyrene foam.

Polyurethane foam

Insulation of the foundation of a house from the outside is also carried out using liquid insulation, which is sprayed onto the base using special equipment and quickly hardens. Polyurethane foam is able to protect concrete well from negative impacts, since in addition to standard characteristics it has a number of advantages:

• It is applied in a continuous layer without joints or gaps, which makes thermal insulation more effective.
• fills all cracks and potholes that may have appeared during operation.
• The composition hardens quickly, so the base can be sheathed with finishing materials immediately after thermal insulation work is completed.
• Performs the function of waterproofing.
• It adheres to concrete, brick and wood bases because it has excellent adhesion properties.

Thanks to these advantages, polyurethane foam is gradually replacing polystyrene foam and penoplex in private construction. But there is one difficulty. It is impossible to apply insulation without special installation.

Expanded clay

Before the advent of modern synthetic materials, expanded clay and slag were used. These materials are inexpensive and have low thermal conductivity.

But in order to properly and effectively insulate the foundation with expanded clay, it must be used in large quantities. In addition, the process of arranging bulk thermal insulation is multi-stage and labor-intensive. There are, of course, some advantages:

1. Economy option - affordable price.
2. Everything can be done with your own hands without the help of professional craftsmen.
3. Expanded clay is a cheap material.
4. Used for horizontal (on the ground) and vertical insulation.
5. Safety for human life and health, as well as the environment.

How to insulate the foundation of a house with polystyrene foam from the outside

In order to install tile insulation, you must first prepare the work site. To do this, the following activities are carried out:

1. A trench about 1 m wide is dug along the perimeter of the entire building. The depth will vary depending on the depth of the foundation and freezing of the soil.
2. The surface of the base is cleaned of dirt with a stiff brush.
3. The open foundation is left for 10 days to evaporate moisture.
4. The surface is inspected for defects. If they are large, then they do plastering.
5. Small cracks and crevices are sealed.
6. Provide waterproofing. For this purpose, mastics based on polymers, rubber or bitumen are used. Organic ones are not suitable because they will destroy the insulation.

Before using mastic, the foundation is treated with a bitumen primer, which will improve adhesion. Waterproofing is applied in 2 layers, carefully treating the corners and not leaving bald spots.

After the mastic has dried, polystyrene foam is glued to the outside of the base. Be sure to choose an adhesive that will withstand high humidity and temperature changes. If the base was treated with bitumen mastic, then it is also used as glue.

1. The adhesive solution is applied around the perimeter of the insulation board and several strokes in the center.
2. The element is applied to the lower left corner and pressed tightly.
3. After fixing, check with a building level.
4. The next part is placed as close as possible to the adjacent one so that a minimum gap remains.
5. If polystyrene foam insulation needs to be laid in several rows, remember to bandage the vertical seams.
6. After completion of the work, the parts that will be above ground level are additionally secured with dowels with wide heads.
7. The joints are additionally filled with sealant.

After the glue has completely dried, the trench is filled up leaving 30 cm to the ground level. The earth is carefully compacted, lined with a waterproofing film (it is placed on the foundation), drainage pipes are laid, covered with gravel and sand, compacted again and a blind area is made.

Insulation that is located above ground level requires decorative finishing. To do this, choose basement siding or other durable material. A block house made of wood should not be chosen as a finishing material; over time, the cladding will lose its attractiveness rather than become prettier.

Features of installation of thermal insulation made of polyurethane foam

If polyurethane foam is used to insulate the foundation of houses, then there is no need to first level the surface and cover it with waterproofing. It will be enough:

• Dig a trench.
• Clean the foundation from contamination.
• Dry.
• Inspect the base. If there are old pieces that are peeling off, they are removed and sealed.
• Then polyurethane foam is applied.

Everything dries out very quickly, so you can immediately begin arranging the blind area, and then the exterior finishing.

Insulation of the foundation using the backfill method

As with the previous two options, you need to dig a trench. To save your time, you can hire special equipment. The bottom of the trench is completely cleared of plant roots, and the foundation wall is free of dirt and dried. Be sure to cover the base with 2 layers of bitumen mastic.

• A waterproofing film is placed in the trench, the edges of which should extend onto the foundation wall.
• Fill in a small layer of sand and compact it.
• Install drainage pipes.
• Expanded clay is poured with a slope of 5 degrees from the wall.
• Add another layer of sand on top and compact it.
• They make a blind area.

Drainage of water from the base

Since precipitation constantly affects the foundation, care must be taken to ensure that the water does not stop near the walls, but is directed further away. To do this, install drainage during insulation.

1. It is better to lay drainage pipes below the level of the foundation base or basement floor.
2. Communications are protected with geotextiles.
3. The pipes converge into a drainage well, which is located 5-6 m from the building.
4. When arranging the blind area, do not forget about the slope, which will help remove moisture from the walls and direct it to the drainage.

Methods for insulating different types of foundations

For the construction of houses, a suitable option for arranging the foundation is chosen. But each of them requires its own insulation technology. You shouldn’t use one for everyone because it will be difficult to achieve the desired result.

Strip foundation

This type of foundation can be insulated in two ways:

1. Horizontally - fill in expanded clay and make a blind area.
2. Vertically - use sheet or liquid insulation.

Such options have been described above. They are perfect for a strip foundation and will protect against negative influences. They carefully select the insulation, because its quality determines how warm and comfortable it will be in the room, and how long the foundation will last.

Columnar foundation

In this option for arranging the foundation, everything is a little more complicated. First you need to make a fence, which serves as a foundation wall. To do this, choose brickwork or make a frame from metal profiles or wood.

For brickwork, you will need to make a small trench, which is filled with sand and crushed stone, and a metal profile is laid on top. This design will be the basis for a brick wall. Next, a basement is built.

After the solution has dried, the wall can be additionally insulated with foam boards (or polystyrene foam) and plastered. Any durable material is suitable for decorative finishing. If a frame made of metal or wood is chosen for a pile foundation, it is also filled with insulation and lined. The metal profile is secured by welding.

Slab foundation

Insulation of the slab foundation begins after the foundation pit has been prepared. A sand cushion is poured onto the bottom and compacted. A waterproofing film must be laid on top of the sand. Then insulation is placed over the entire area of ​​the house, each next row is shifted to bandage the seams.

Then they begin to arrange the formwork around the perimeter of the laid insulation. Steel rods for reinforcement are placed in the formwork. Everything is filled with concrete. After the solution has completely hardened, they begin to create a blind area.

Most owners of private houses do not consider it necessary to insulate the foundation, believing that it is a waste of money. Thoughts about the need to insulate the base from the outside come when problems with dampness and mold on the walls become visible, and the base begins to become covered with cracks. High-quality self-made waterproofing will help you avoid these troubles; we’ll tell you how to do this in the article.

Insulating the basement is as important as insulating the walls of the house. The room loses about 20% of heat through the foundation. Many people think that it is enough to insulate only the basement, but this is a grave mistake. Since the destructive force of water and low temperatures continues to act on the base. Moisture entering the pores of the foundation freezes when exposed to low temperatures and, expanding, destroys the structure. Microcracks appear, which become cold bridges, and as they increase, they can lead to the destruction of the building as a whole.

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

Advantages of insulation

If the foundation is not insulated, cold air from outside enters the living space through the flooring. Therefore, when building a house, the floors are raised above the ground level. Without insulation from the outside, constant dampness in the basement and cold floors in the house are guaranteed, which reduces the level of comfort. So, what facts speak in favor of insulation:

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

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

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

Insulation methods

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

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

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

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

Insulation with expanded clay

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

Warming is carried out as follows:

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

Sheet material insulation technology

When constructing a new building, insulation work begins after installation of the floor slab. If the house has already been built, then the foundation is dug around the perimeter to the base a meter wide. The walls are dried and all dirt is removed. If the groundwater level is close, drainage is arranged. After complete drying, a latex-based primer is applied to the foundation walls. It fills small voids and ensures strong adhesion of the waterproofing to the surface of the base. Roll waterproofing is laid, pressing firmly with a roller. The joints are covered with sealant for reliability. They wait until the waterproofing dries, and then begin laying the insulation.

Advice. Do not use slabs torn from the surface or displace them after the glue has hardened.

Advantage of extruded polystyrene

Expanded polystyrene boards are considered the best option for private construction. Because they have a long service life and high compressive strength. They practically do not absorb or allow moisture to pass through. It retains its thermal insulation characteristics for a long time precisely due to its low hygroscopicity.

These plates are produced with special grooves. They drain moisture into the drainage. In tandem with geotextiles, polystyrene, in addition to insulation, serves as waterproofing and wall drainage.

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

Insulation with liquid polyurethane foam

Polyurethane foam is applied in foamed form to the cleaned surface of the foundation. It combines the properties of waterproofing and thermal insulation. 50 mm of polyurethane foam is equal to 1.2 m of polystyrene foam. The material hardens very quickly, forming a cellular structure. The foam hermetically envelops the foundation, leaving no gaps or forming seams, unlike tile insulation. The advantages of polyurethane foam insulation include:

• no seams in the coating;
• high adhesion of the material;
• there is no need to install waterproofing;
• low vapor permeability;
• service life more than 40 years;

• low thermal conductivity;
• environmentally friendly and biologically neutral.

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

Drainage of water from the base

Along with insulation, it would be good to provide drainage so as not to dig up the foundation twice. Drainage pipes are laid below the level of the base of the foundation or below the level of the basement, if there is one. A gravel bed is poured with a slope of 5 degrees. A drainage pipe wrapped in geotextile is placed on top of it, and gravel is placed on top. Geotextiles will prevent clogging of drainage holes. Groundwater will flow through pipes into a drainage well.

Having knowledge about the advantages and disadvantages of insulation, you can choose the material that suits you best. Carry out construction work competently, and you will ensure long-term comfort and warmth in the house, as well as long service life of the building.

Insulating the foundation with polystyrene foam: video