The better way to insulate the foundation from the street. Do-it-yourself insulation of the foundation of a private house from the outside. Thermal insulating polystyrene boards with milled grooves

Insulating the foundation from the outside is necessary work to ensure the preservation of heat in the room, protection from moisture, and saving energy resources.

The optimal solution is to carry out all the manipulations during the construction of the building, but it is possible to implement the plan after the construction of the building is completed.

For each individual case, we have developed our own most convenient algorithm, according to which the foundation of a private house should be insulated from the outside, and materials have been selected that allow us to achieve the highest quality and most effective insulation of the foundation.

Variety of materials for thermal insulation

Insulation of the foundation base from the outside is carried out:

Each of the listed materials is ideal for providing high-quality insulation of the foundation of a house from the outside.

In all cases, it should be remembered that thermal insulation of the foundation is not necessary in order to increase the flow of warm air entering the room. Every effort should be made to prevent the cold from penetrating into the building.

The insulation must be moisture resistant

If they want to avoid material costs and save as much as possible on arranging a warm foundation for a house, many owners of private buildings carry out all the work using the ground. The backfill method allows you to achieve a positive result, but modern materials guarantee that a reliable and high-quality warm foundation will be created.

When deciding how to insulate the foundation, you must first choose the method of performing the work, because the thermal insulation material can be fixed on the outside of the building or on the inner surface of the base.

Depending on which insulation was chosen and on the method of insulation, materials for insulating the foundation necessary to achieve the goal are selected.

You can purchase everything you need if you know how to properly insulate the foundation of a residential building in order to provide the owners with comfortable living conditions. The materials used should not be deformed under the influence of aggressive environments or allow moisture to pass through. They must be characterized by a long service life, resistance to temperature changes, low weight, strength and high density.

Taking into account all the requirements, experts recommend using the following as insulation:

penoplex;
extruded polystyrene foam;
sprayed polyurethane foam.

Before insulating the foundation of a house from the outside with your own hands, it is necessary, in strict accordance with all requirements, to prepare the base surface on which the thermal insulation material will later be fixed.

To spray polyurethane foam you will have to invite professionals with equipment

Spraying polyurethane foam requires the participation of craftsmen and the use of special equipment; in addition, such a coating is resistant to exposure to ultraviolet rays.

That is why owners of country buildings strive to insulate the foundation of a private house using penoplex, which is cheaper, but quite durable and of high quality.

Insulating the outside of a house with polystyrene foam is also popular because it does not require the use of special fasteners. To securely fix it, it is enough to use an adhesive composition similar to polyurethane foam. This is foam cement.

Execution of work

Knowing how to insulate a foundation from the outside, you can correctly select the most suitable material and prepare the foundation.

This stage requires special attention, since the algorithm for performing the work depends on the features of the constructed frame. In cases where we are talking about piles or pillars, then the construction of a brick wall will be required to fill the gaps between already installed piles or pillars:

You will have to dig a trench around the entire perimeter of the house and place a sand cushion at the bottom, which will need to be thoroughly compacted.
The second stage is laying the reinforcing mesh, on top of which the concrete base is poured.
After 10 days, the concrete will gain strength and laying can begin.

Another option that is considered when deciding what and how to make a warm foundation is to use slag or expanded clay. Having decided how to insulate the foundation of the house, you can begin making calculations and purchasing materials.

Surface preparation begins with sealing all detected defects on the outer surface of the foundation base of an already constructed building.

For this purpose, you can use a sand-based plaster mixture, and the largest cracks can be filled with polyurethane foam. Primer is applied on top of the plaster. This should be a deep-penetrating composition that ensures high-quality adhesion of materials. For more information about insulating the base, watch this video:

Having made the final decision on how to insulate the foundation from the outside, you need to take care of arranging high-quality waterproofing. To treat the foundation from the outside, coating materials such as bitumen mastic are needed.

From the outside, the foundation is insulated in two layers

Now it's time to attach the first layer of polystyrene foam. It is necessary to apply an adhesive composition to it and press it tightly to the surface that is being insulated.

All seams and joints are foamed and after the foam has hardened, it is cut off and the entire covered area is covered with reinforcing mesh to create a second layer of plaster.

To insulate the foundation from the outside, two layers of polystyrene foam are required. The final decoration will be:

slabs;
panels;
plaster and paint;
tile.

Before choosing the best way to insulate the foundation of a built house, you need to decide what and how to insulate the area underneath it. To do this, you should know how to insulate the foundation, given that much depends on the quality of the floor. Penetration of cold air is possible from the underground or basement. Treatment of old floors, during which it is good to use modern insulating materials. For more information about the stages of work, watch this video:

By considering various methods and options for foundation insulation, you can see that this process is not as simple as it might seem.

Failure to comply with the nuances of the technological process causes disruption of the microclimate in the room, heat loss, and unjustified energy costs.

However, knowledge of the features of each individual structure and the building materials used for its construction will help to achieve success. So, for example, a concrete base is insulated only from the outside, because practically no cold air passes through it, but the false base of a pile foundation requires mandatory insulation of the inner surface.

Insulating the foundation from the outside is a necessary measure to create a comfortable temperature in the house and basement. Thermal insulation of the foundation and basement allows you to save on energy costs for heating the house, which will please any owner.

Insulating the foundation from the outside - a rational solution or a waste of time?

The foundation is the basis of any house, building or structure. High-quality construction of this foundation will help to avoid future problems such as wall cracks, building subsidence, etc. Proper operation of the foundation, in turn, will solve the problems of wear and loss of structural strength. Therefore, thermal insulation is a necessary measure to protect the foundation and base of a house from the influence of the external environment.

Insulation of a concrete base is usually carried out on the outside of the house. An option is possible when the foundation is insulated from the inside, but this is done if it is impossible to insulate the building from the outside for some reason. Insulation from the outside is more profitable, since freezing and the formation of condensation moisture occurs from the street. For greater efficiency, you can combine these two options by isolating the foundation from the outside and inside.

Proper and timely insulation of the foundation will help avoid the following problems:

formation of condensation on the walls of the basement. The basement must be dry to ensure the safety of supplies, and condensation leads to the formation of mold and mildew. Thus, not only food, but also building materials deteriorate;
cold floor in the house. Waking up in the morning and standing on an icy floor straight from a warm bed is invigorating, but very unpleasant. As you know, your feet should be warm. Therefore, cold floors not only conduct cold into the room with impunity, but can also easily cause colds;
cracks in the foundation. Cracks form due to frost heaving of the soil. Soil heaving occurs when wet soil suddenly freezes, and at this moment it is able to exert strong pressure on the foundation. Therefore, waterproofing in the insulation process is a very important stage.

So, the need for external thermal insulation comes down to the following points:

protection of the foundation from freezing and temperature changes;
increasing the service life of communications;
increasing the service life of the foundation structure;
protection from moisture and soil heaving;
absolute savings in energy costs.

Stages and options for insulating the foundation from the outside

Ideally, the foundation should be insulated at the stage of building a house when there is free access to the entire surface. To isolate the foundation of an already built house, you will have to carefully dig it out and clear it of soil. Work will need to be carried out carefully to prevent cracks from occurring. But, nevertheless, in both cases the thermal insulation will be effective.

When insulating the external foundation, polystyrene foam, extruded polystyrene foam, polyurethane foam and expanded clay are used. The most popular insulation material is polystyrene foam, which is probably due to its advantages: affordable price, resistance to moisture and ease of use. At the same time, it is necessary to remember about its low degree of fire resistance.

Insulation of the foundation from the outside is divided into several stages:

Preparatory work. It is necessary to remove the soil to the freezing depth and to a width of about 50 cm. The foundation is cleared of soil and dust. Next, you need to seal all the seams and cracks in the foundation with primer and construction foam.

The depth of soil freezing is an indicator whose value varies depending on the climatic zone and soil composition. The lower the temperature drops, the greater the freezing depth. The value of this indicator by region and region can be found in SNiP (building codes and regulations).

Waterproofing. To insulate from moisture, you can use rolled bitumen or liquid rubber. Liquid rubber is applied with a spatula to the primed surface, and rolled materials are secured by heating them with a torch.
Insulation of the foundation. After the waterproofing layer has taken its place, you can begin direct thermal insulation.

Polystyrene foam and polystyrene foam. If the waterproofing was done with bitumen, then it must be heated with a burner and foam plastic/expanded polystyrene boards attached to it. In the case of liquid rubber, you can use mastics. They are applied pointwise or stripwise onto the foam and attached to the foundation. In both cases, you can install the insulation using mushroom dowels (4–5 pieces per sheet). The seams between the sheets are closed with reinforced mesh and cemented.
Polyurethane foam. It is applied by spraying, thanks to which it fills all cracks and leaves no seams. Clings well to any surface. The required layer of polyurethane foam is from 5 cm. Spraying requires special equipment and the help of specialists.
Expanded clay. In this version of thermal insulation, it is necessary to simply pour expanded clay into the prepared trench. The dimensions of the trench for this insulation should be 1 m wide. Roofing felt is also useful to cover the expanded clay on top and lay it on the bottom of the ditch as waterproofing.

Before filling everything with earth, it is recommended to apply another layer of waterproofing material if the insulation was done with polystyrene foam or polyurethane foam.

How is the basement insulated from the outside?

The base is the upper part of the foundation, which is in contact with both the floor of the building and the underground part of its base. An uninsulated base is a good conductor for cold air and dampness. Therefore, the comfortable temperature in the house directly depends on the level of thermal insulation of this area of the exterior of the house. The role of insulation for the base will be taken over by the already familiar polystyrene foam and extruded polystyrene foam. Perhaps there is something left after insulating the foundation, then it will be profitable to purchase the required amount of material, and you can get to work.

Thermal insulation of the base from the outside consists of several stages:

First you need to make markings. You need to use a level (laser or water) to determine the top point of the basement finishing and stretch horizontal ropes around the perimeter of the building.
Prepare the surface. Cleaning from dirt and priming with a deep penetration compound.
Prepare sheets of polystyrene foam/expanded polystyrene. If the wall protrudes further than the base and vice versa, then the sheets must be cut in accordance with the size of the protrusion.
Insulation of the basement from the outside. It is better to start thermal insulation from the corner of the house. Glue is applied to the foam sheet with a notched trowel and pressed tightly against the surface of the base along the line of the stretched rope. To prevent the insulation board from moving, it can be secured with dowels or screws.

The dowels must be plastic, since, unlike metal ones, they do not conduct cold air, i.e. do not create cold bridges in the places where the insulation is attached.

Insulation finishing. After the entire base has been insulated, it needs to be treated with a primer, and the façade corners must be attached to the corners. You need to glue a reinforcing mesh onto the surface of the foam plastic; cement glue is useful for this. When the glue has dried, you can putty the surface with a solution for exterior use. Apply another layer of primer to the dried putty and you can finish lining the base (painting, fastening decorative elements).

When constructing a capital structure, it is wise to insulate its foundation in advance. Completing the task prevents the accumulation of condensation in the basement, which has the most negative impact on the operation of the building.

From the outside it cannot be called a simple procedure. However, if you approach the matter responsibly, you can do the work efficiently with your own hands. Let's try to figure out how to properly insulate the foundation during the construction of a structure and during its operation.

Criteria for selecting insulating materials

Materials for insulating the foundation from the outside should be selected based on the following criteria:

Thermal conductivity coefficient - the lower this indicator, the better the insulating qualities of the material.
The thickness of the insulation layer - this parameter directly depends on the previous one.
Durability and resistance to moisture.
Cost – thermal insulation with a wide range of useful qualities has an increased price. However, in most cases the need for the most reliable insulation is minimal.

Types of insulation

If it is decided to perform external insulation of the foundation, then the technology for laying insulation will depend on the choice of material. It is strongly recommended to choose insulation materials with a minimum thermal conductivity coefficient.

Since the insulating material is laid directly into the ground, it is constantly exposed to moisture. Therefore, an important characteristic for insulation is the presence of water-repellent properties.

Styrofoam

Insulation in the form of polystyrene foam is produced in standard sheets measuring 1x1 meter and 20 mm thick. The insulating base is produced by foaming polymers and therefore consists of more than 90% gases.

Polystyrene foam retains heat well, absorbs little moisture, but quite quickly loses its original structure when exposed to direct sunlight. The material is difficult to cut accurately, as its structural elements crumble easily.

Expanded polystyrene

Derived material from polystyrene foam. It is produced by the polymerization of steam pentane and styrene.

Based on production technology, autoclaved, pressed and extruded polystyrene foam is distinguished.

High-density pressed material is suitable for insulating the foundation of a private house. Compared to polystyrene foam, the thermal conductivity of such an insulator is significantly reduced.

Expanded polystyrene can be cut to form clear edges. The material is characterized by increased strength and is resistant to moisture, so it is good for insulating the foundation from the outside.

Expanded clay

As for the use of a material such as expanded clay for, here, first of all, it is worth noting its cheapness. However, despite the low cost, this insulating base has a wide range of useful characteristics.

The material is resistant to sudden temperature fluctuations, precipitation, and difficult, changeable weather conditions in general. Like foam plastic, expanded clay has a porous internal structure. It perfectly absorbs moisture, but is not destroyed by its influence. Typically, expanded clay is laid on a protective oilcloth film or roofing felt, which plays the role of waterproofing.

Features of insulation of strip and pile foundations

The strip foundation is laid using monolithic concrete, brickwork or concrete blocks. When arranging a thermal circuit, frameless (adhesive) or frame technology for installing external insulation can be used here.

Do-it-yourself insulation of a foundation on screw piles requires the creation of a frame. Since the piles here act as point supports, which are not capable of forming a surface for laying insulation along the entire perimeter of the building.

When laying a pile foundation, a false base is created, and the installation technology involves laying both external and internal insulation. The frame prepared for the pile foundation is securely fixed directly to the point supports.

Returning to the issue of insulating a strip foundation, it is worth noting that a frame can also be constructed for this purpose. To create it, wooden blocks or metal profiles corresponding to the thickness of the insulation are used.

Foam insulation

External insulation of the foundation of an already operating house using polystyrene foam requires a number of preparatory measures. First of all, a layer of soil is removed to the depth of freezing of the ground. The substrate is thoroughly cleaned of debris and soil residues. Next, waterproofing work is carried out.

Waterproofing

It is rational to use bitumen in rolls or liquid rubber as waterproofing. First, the foundation substrate is primed. To do this, molten bitumen or rubber is mixed with diesel fuel in a 1:1 ratio, after which the surfaces are primed with the mixture.

After the substrate has dried, the selected waterproofing is applied directly to the outer surface of the house foundation. If molten rubber can be applied with a spatula or brush, then the underside of the rolled bitumen will have to be heated with a burner and only then attached to the foundation.

Installation of insulation

After completing the preliminary waterproofing work, you can proceed to the installation of foam plastic. Here you will also need to use a torch. With its help, the surface of the waterproofing material is heated, after which the foam sheets are attached. As an alternative, special mastic can be used for reliable fastening.

Having laid the foam with your own hands, it must be covered with soil. It should be noted that before backfilling the material, it is necessary to first install a layer of roofing felt between the soil and the foam. This avoids damage to the insulator by moisture and small pests.

Stages of polystyrene insulation

To thermally insulate a foundation of insignificant height, laying one row of polystyrene slabs is sufficient. High foundations are insulated with the specified material in several rows. In this case, the slabs are laid in a checkerboard pattern to avoid the formation of vertical seams.

It is not necessary to attach polystyrene to the substrate, since when backfilling the soil will press the insulation to the foundation of the house. The gaps are filled with sealant or foam. In this way, the formation of “cold bridges” can be prevented.

Preliminary filling of polystyrene is carried out with a mixture of dry sand and fine gravel, not reaching the upper level of the insulating material. The upper part of the polystyrene slabs is attached to the foundation with special dowels with a wide head. To do this, holes are drilled in the concrete to a depth of about 5-7 cm. Each slab is attached to 4-5 dowels, which are driven in with a hammer.

The simplest and most affordable way to insulate the foundation from the outside with your own hands is to use expanded clay. Not so long ago, this option was the most common.

Today, due to the emergence of a wide range of innovative materials, thermal insulation with expanded clay is gradually fading into the background.

Preparatory activities

The procedure for insulating the outer side of the foundation with expanded clay is in many ways similar to using polystyrene foam. First, a trench of the required size is dug. Next, the insulation is prepared, which will be laid on the substrate and pressed with soil to the outer surface of the foundation.

Backfilling of heat insulator

The trench next to the foundation is pre-covered with plastic film.
A layer of expanded clay is poured to the entire depth of the trench. In this case, the thickness of such a heat insulator should be at least half a meter.

Finally, the thermal insulation material is wrapped with a film on top. The surface of the expanded clay is covered with roofing felt and covered with soil.

It is better and more comfortable to engage in the construction and insulation of the foundation in the spring-summer-autumn period, when the air temperature is quite high and the humidity “does not go off scale”... Let's figure out how to insulate the foundation from the outside correctly and effectively!

Why is it necessary to insulate the foundation?

Using insulation for the foundation is just as important as insulating the walls of the house! Especially in areas characterized by a harsh climate and freezing of the soil to great depths. The foundation of a building structure “gives” 10-20% of the total heat loss of the building to the environment.

A particular danger for building foundation structures is the freezing of so-called “heaving” soils. Such soils are capable of freezing during severe frosts and significantly increasing in volume, which leads to a rise in ground level.

Attention! At significant depths of soil freezing, a “movement” of its level by 35 cm is possible. This value corresponds to 15% of the soil freezing depth.

The rise in ground level leads to deformation of the building foundation. If the foundation is laid above the freezing level and the foundation slab is not insulated, then during the period of freezing, frost heaving forces arise under this slab, directed normally (perpendicularly) to the surface of the slab. Therefore, in freezing zones, thermal insulation of the horizontal foundation slab is also carried out.

The quality of work in this thermal insulation direction will determine the operating conditions of the building as a whole and the comfort of living in it. Planning of foundation insulation work is carried out at the stage of its construction.

Since a large “amount” of cold enters the house through the foundation, when building a house, floors raised above ground level are used. Cold air in large volumes is located at the level of the foundation and floor, and warm air rises up and, if the roof is poorly insulated, goes outside, making room for a new “portion” of cold air.

And if the basement is used for any functional purposes (not a cellar), then special attention should be paid to its insulation. Game room, gym, billiard room, laundry room - no matter what the purpose of the room is, a comfortable air temperature in it is important. And the presence of dampness without insulation of the foundation is guaranteed.

An unheated basement is “undemanding” in terms of thermal insulation. But the basement part of the foundation should be insulated. to reduce heat loss at the floor level of the first floor, which is heated.

Insulating the base of the foundation will allow you to save heat in the house by blocking the path of cold air into the house. Remember that high-quality insulation of a house, including the foundation, allows you to save from 30 to 50% of the money allocated for heating.

In addition to thermal insulation functions, the foundation insulation layer plays an integral role in its waterproofing.

So, insulating the foundation:

reduces heat loss;
reduces heating costs;
reduces or completely eliminates the impact of frost heaving forces on the foundation;
stabilizes the temperature inside the building;
prevents the formation of condensation on the internal planes of the walls;
plays the role of mechanical protection of waterproofing;
has a beneficial effect on the longevity of waterproofing and the foundation structure as a whole.

Which foundation insulation to choose?

Planning insulation work includes the main step - choosing a thermal insulation material. So, what is the best way to insulate the foundation of a house?

Such materials for foundation insulation should:

do not deform under soil pressure;
do not absorb moisture.

Today it is easy to “get lost” in all the variety of heat-protective materials. It is clear that the common insulation material mineral wool is not suitable here due to its “softness” when backfilled with soil and high water absorption, which reduces its thermal insulation qualities.

To insulate the foundation today, experts recommend two main methods:

insulation with extruded polystyrene foam;
spraying polyurethane foam.

These insulation materials differ in different thermal insulation parameters and costs. To make the optimal choice, you need to study their advantages and disadvantages.

This is a modern thermal insulation material that combines the functions of heat, hydro and sound insulation. To use it, you need special equipment with which polyurethane foam is sprayed layer by layer onto the surface to be insulated. The thickness of the insulating layer is 50 mm and this is with a polyurethane foam density of 36 kg/m 3. A similar insulating effect can be achieved by using polystyrene foam with a thickness of at least 120 mm.

There are no gaps or seams in the polyurethane foam coating, which are cold bridges and a “path” for moisture to penetrate into the foundation. When insulating with foam plastic, it is necessary to seal and seal the joints, as well as use additional mounting fasteners, which increases the installation time and their cost.

Advantages of using polyurethane foam:

seamless coating;
high adhesive properties;
low thermal permeability;
low vapor permeability;
reliability;
"longevity";
no need for additional vapor and waterproofing.

The disadvantages of this material include the need for special equipment and the “fear” of UV radiation.

In its defense, extruded polystyrene foam can only “present” a lower cost, the significance of which is reduced by the complexity of installation and lower thermal insulation properties.

Plates made of extruded polystyrene foam, due to their closed cellular structure, practically do not absorb and, naturally, do not allow water to pass through. This means that the moisture in the slabs will not destroy them when they freeze. Therefore, extruded polystyrene foam is characterized by a long service life while maintaining its thermal insulation characteristics.

Note! To the question: “How to insulate a foundation with foam plastic?”, we offer the following answer...

Using ordinary foam plastic to insulate the foundation can lead to the fact that after several cycles of seasonal “freezing - warming up” of the foundation, the insulation layer will crumble into a pile of balls. This will happen due to moisture, which ordinary polystyrene foam easily absorbs.

Vertical thermal insulation of the foundations of civil and industrial facilities is carried out with extruded polystyrene foam slabs with a compressive strength of 250 kPa or more; private buildings allow the use of expanded polystyrene with a strength of up to 200 kPa. For flooring, it is necessary to choose slabs with a strength of 500 kPa or more.

Such “strength” characteristics of extruded polystyrene foam have a beneficial effect on maintaining the integrity of the foundation waterproofing and are its integral element, ensuring the normal long-term existence of the foundation.

Among the thermal insulation materials made from extruded polystyrene foam there are slabs with milled grooves. In collaboration with geotextile fabric, this material perfectly performs the function of wall drainage, insulating the foundation, protecting waterproofing and diverting water from the foundation to the drainage system.

Advantages of insulation with extruded polystyrene foam:

long service life (at least 40 years);
high compressive strength;
constancy of thermal insulation properties during operation;
"inedible" for rodents.

Foundation insulation with expanded clay

Until recently, this was the most popular method of insulating the foundation from the outside. It has been supplanted by the relative “cheapness” and high efficiency of the methods discussed above on how to insulate the foundation from the outside.

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

Correct and effective insulation of the foundation from the outside in zones of soil freezing involves installing heat-insulating slabs to the freezing depth. Insulation of the foundation (walls) below the soil freezing level is not as effective and is often not carried out.

The corner zones of the building require “reinforced” thermal insulation. Therefore, at a distance of 1.5 m from the corner, the thickness of the polystyrene foam slabs or polyurethane foam layer increases by 1.5 times.

It is also necessary to insulate the soil around the perimeter of the building. An insulating layer made of extruded polystyrene foam is located under the blind area structure. Its main purpose is to reduce the depth and degree of soil freezing along the walls, as well as to maintain the freezing limit in a layer of non-heaving soil (sand, gravel, etc.) buried along the walls.

The laying angle of extruded polystyrene foam slabs must be at least 2%, and the width of the blind area must correspond to the depth of soil freezing in the given region. The optimal thickness of the slabs corresponds to the thickness of the vertical insulation layer of the foundation.

Before insulating the foundation of a house from the outside, the surface of the walls must be leveled and waterproofing must be done on it.

When installed, extruded polystyrene foam slabs create an airtight shell for the foundation. Therefore, the use of mechanical fasteners for their fixation is unacceptable due to point depressurization of the insulation layer.

Fixing the heat insulation slabs is carried out by applying an adhesive composition to them or by “melting” a layer of bitumen waterproofing at 5 or 6 points, to which the polystyrene foam slab is then pressed and held for some time until it hardens.

Installation of slabs begins from the bottom, the rows are connected end-to-end. The thickness of the plates must be the same. The vertical seams of adjacent ones should be offset relative to each other (checkerboard order).

Attention! The use of torn slabs for re-installation is not allowed, as is the displacement of slabs after the bitumen or adhesive solution has hardened.

The seams between slabs with a thickness of more than 5 mm are filled with polyurethane foam; it is more convenient to use slabs with a stepped edge. Its gluing will ensure the tightness of the heat-insulating layer and additional waterproofing of the foundation.

The adhesive is selected based on the material of the waterproofing layer. The use of roll or mastic waterproofing materials based on bitumen determines the use of bitumen mastics as an adhesive composition that do not contain aggressive ingredients for polystyrene foam.

Attention! Before insulating the foundation from the outside, you must wait until the bitumen waterproofing has completely dried (5-7 days). You cannot install slabs of extruded polystyrene foam on a wet base of bitumen waterproofing, as the slabs can “move apart” and damage the waterproofing. Also, the composition of bitumen waterproofing may contain solvent particles, which, in their “undried” form, can harm polystyrene foam boards.

Glue is applied to slabs located below ground level in several points. This will allow the moisture that condensed between the surface of the insulation and the foundation wall to flow down without hindrance.

The use of fastening dowels together with the adhesive composition of polymer-cement adhesives is necessarily applicable for polystyrene foam slabs located above ground level at a rate of at least 4 pieces. for one slab. The slabs located in the ground are attached only to the adhesive composition and are pressed with a layer of soil.

Features of installation of thermal insulation made of polyurethane foam

Foundation insulation with polyurethane foam is performed in this way. Let's watch the video...

How to insulate a foundation slab?

When deciding how to insulate the foundation from the outside, for more effective insulation of the floor or basement, you should take care of insulating the foundation slab.

In this case, the insulation boards are laid on a layer of waterproofing.

Further, if knitted reinforcement is used to fill the power floor, it will be enough to cover the layer of heat insulation with polyethylene film with an overlap of 100-150 mm and gluing with double-sided tape.

When using a welded reinforcement structure, it is necessary to make a protective screed of concrete or cement-sand mortar on top of the film, and then carry out welding work on top of it.

Foundation insulation

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

Do I need to insulate the foundation?

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

This way, insulating the floor prevents cold from penetrating into the room through the ceiling.

Thermal insulation of the foundation performs the following functions:

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

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

External insulation of strip foundation

First of all, let's look at how to insulate a strip foundation, which is the most common.

There are two ways to insulate such a base:

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

Often, internal insulation is performed together with external insulation. Next, we will consider both thermal insulation options.

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

Preparation of materials

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

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

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

The only drawback of expanded polystyrene is the high price, which averages 4,500 rubles per 1 m2.

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

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

drainage;
adhesive foam for penoplex;
roll waterproofing, for example, roofing felt;
materials for pouring the screed (needed for arranging the blind area).

Excavation work

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

Excavation work is carried out as follows:

First of all, you need to dig out the strip foundation. To do this, dig a trench to the entire depth of the foundation, about one and a half meters wide. After that the foundation should be left for some time to dry thoroughly;

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

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

It is necessary to start excavation work in dry, warm conditions. Therefore, it is best to insulate the foundation in late spring or summer.

The excavation work has now been completed.

Foundation preparation

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

The work is performed in the following sequence:

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

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

It is necessary to fill all the depressions, cracks, etc. with mastic to form a continuous coating with a thickness of about 2-4 mm.

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

Installation of insulation

The installation instructions for penoplex look like this:

Apply glue to the back of the insulation. The glue should be located around the perimeter of the slab, as well as in the center;
then the slab must be applied to the surface of the foundation and pressed down lightly. Start covering the foundation from the corner.

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

As a rule, it is impossible to perfectly cover the foundation with insulation boards. Therefore, you need to inspect the walls and fill the existing cracks with adhesive foam.

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

Arrangement of the blind area

Now you need to make an insulated blind area by following these steps:

the pit around the perimeter of the house must be filled with earth so that a trench about 30 cm deep from the ground level remains;
then fill the trench with sand about ten centimeters thick and compact it thoroughly;

roofing material should be laid over the trench close to the walls of the house. Glue the roofing felt joints that should overlap each other with bitumen mastic;

then penoplex is laid on the waterproofing;
A screed is poured over the penoplex according to the standard scheme.

At this point, the insulation of the foundation from the outside is completed.

Thermal insulation of strip foundation from the inside

Do-it-yourself foundation insulation from the inside can also be divided into several stages:

The basement can only be insulated after it has been thoroughly waterproofed, since the room must be dry.

Preparation of materials

To insulate the foundation from the inside you will need the following materials:

slab insulation - you can use any, including polystyrene foam or even mineral wool;
glue for insulation;
umbrella dowels;
primer;
reinforcement fiberglass mesh.

Preparing the walls

Before you insulate the foundation of a house from the inside, you must prepare it:

First of all, the walls must be cleaned of dirt and dust, as well as old peeling finishes, if any. To do this, they can be cleaned with a brush and then wiped with a damp cloth;
then the surface of the foundation must be coated with a primer. If the base is concrete, use an adhesive primer. In other cases, you can use universal primer.

The primer is applied with a brush or roller in a thin layer. After the first layer has dried, the procedure is repeated.

Before insulating the foundation, you need to insulate the floor. This operation is carried out according to the same scheme as the thermal insulation of the blind area - waterproofing and insulation are laid, after which the screed is poured.

Installation of insulation

After the walls have dried, we begin installing the insulation:

if a dry mixture is used as glue, it must be diluted in water to a mushy consistency;

the adhesive is then applied to the back of the board using a notched trowel. If the wall surface is uneven, you can apply the glue in lumps;

then the plate is glued to the wall. In this case, adjust its position using a level. The entire first row of insulation is covered using this principle;
the second and all subsequent rows should be staggered so that the seams of the slabs do not coincide. During the installation process, use a level and a rule to ensure that the surface of the walls is level.;

After the glue has hardened, you need to drill holes and install dowels. Each slab must be additionally secured with five dowels. Slightly recess the fastener caps so that they do not interfere with further finishing.

This completes the installation of insulation.

Reinforcement

Insulation reinforcement is carried out as follows:

fiberglass mesh sheets must be cut into strips of the required length;
then glue the prepared mesh to the insulation. To do this, apply the adhesive composition to the wall surface with a notched trowel. Then apply it to the area treated with glue, and move it over it with a wide spatula so that the mesh is immersed in the adhesive solution.

In this way, cover the entire surface of the walls with mesh. In this case, it is important to position it so that each subsequent strip overlaps the previous one by 10 cm;

Apply a second layer of glue with a wide spatula after the first has dried. The layer thickness should be several millimeters.

This completes the work. Now you can prime the walls and putty them to apply the finishing touch.

Thermal insulation of pile-type foundations

Now let's look at how to properly insulate the foundation of a private pile-type house. This work can be divided into 4 stages:

Preparation of materials

To insulate the pile foundation, you need to prepare the following materials:

insulation – the best option is extruded polystyrene foam;
materials for the frame - beams and boards, you can also make a frame from metal profiles;
antiseptic impregnation;

slab isolon;
expanded clay
material for covering the foundation, for example, basement siding.

Frame installation and insulation

When insulating a pile foundation, a big problem is soil heaving. If you place the sheathing close to the ground, it will break as a result of heaving.

As a rule, this problem can be solved by the gap between the sheathing and the blind area. But it leads to a significant decrease in the efficiency of thermal insulation. Therefore, I recommend performing insulation using the technology I invented.

The work begins with the arrangement of the cladding, which is performed as follows:

You need to dig a trench around the perimeter of the house, which will be located above the cladding. The depth of the trench should be 20 cm;
then the trench must be filled with expanded clay. Thanks to this, when the soil heaves, the casing will not break. On top you can lay a layer of sheet isolon (foamed polyethylene) at least 50 cm thick, which will serve not only as insulation, but also as a damper;

Now you can assemble the frame. To do this, beams or boards need to be secured on piles around the perimeter of the house. To fix them, strips with holes for bolts are welded to the piles; you can also use clamps and do without welding;
to increase the strength of the frame, horizontal slats should be connected with vertical posts;
All wooden parts of the structure must be treated with an antiseptic. If you are insulating the foundation of a wooden house, also treat the wooden grillage and the lower crown of the building with a protective compound;

After this, penoplex should be fixed to the frame. To do this, you can use ordinary nails and nails, to which the panels will subsequently be attached;
Fill the gaps between the foam boards with foam;
near the bottom edge of the structure along the perimeter of the house you need to install a starting profile for attaching the panels. Make sure that the panka is positioned vertically;

Install corner profiles at all corners using self-tapping screws. Make sure the corners are installed vertically.

Arrangement of the blind area

The blind area is performed as follows:

dig a trench around the perimeter of the house about 40 centimeters deep and 1-1.5 meters wide;
fill the bottom of the trench with a layer of sand and crushed stone 10 cm thick. Each layer must be thoroughly compacted;
then cover the surface of the trench with waterproofing;

along the outer edge of the future blind area, make drainage according to the scheme described above;
then extruded polystyrene foam is laid on top of the insulation, and the screed is poured on top according to the standard scheme.

Try to make the screed as close to the foundation as possible, so that after covering it, there will be a gap of about 5-7 mm between the blind area and the foundation.

The blind area should have a slight slope from the house so that water does not accumulate at the base.

Frame covering

The foundation cladding is done as follows:

The bottom of the panels is inserted into the starting bar, with which they are connected into a hook. The panels outermost from the corner are inserted into corner profiles. The top panels are attached to the sheathing with self-tapping screws, as shown in the diagram above.
The entire frame is sheathed in this way;

An ebb is mounted on top of the casing, which allows water to be drained onto the blind area. The ebb should be such a width that it covers the gap between the base and the blind area;
At the end of the work, the gap between the blind area and the foundation sheathing should be filled with isolon. Construction sealant can be applied on top. Thanks to this, water will not seep under the foundation.

This completes the process of insulating the foundation.

Conclusion

From this article you learned in detail how to insulate a foundation. I also recommend watching the video in this article. If you have any questions for me on this topic, leave them in the comments, and I will try to answer as soon as possible.