All methods of foundation insulation. Rules for insulating the foundation of a private house How to insulate the foundation from the outside with your own hands













When solving complex issues of thermal protection of a building, among all the options, contractors and owners most often choose the popular method of insulating the foundation of a house from the outside with polystyrene foam. There are other technologies, but unlike wall insulation, not all “usual” thermal insulation materials are used here - the specific operating conditions and a wider range of tasks impose certain restrictions. Since the foundation has not only an underground part, sometimes it is necessary to use a combination of several technologies. How and with what to cover the foundation from the outside to reduce heat loss, we will consider in this article.

A warm home is the care of the owners Source vikonda.zp.ua

Why insulate the foundation

Thermal losses of the building through the foundation are small - from 5% to 15%. Its position and the peculiarities of the “physics” of heat transfer affect it.

About 15% of losses remain on the foundation and floor, but how much this is in absolute value depends only on the owner of the house Source ps-b.ru

There are only three ways to transfer thermal energy: radiation, convection (for gas and liquid media) and thermal conductivity.

Radiation is clearly not “about the foundation”, but about the heating system devices. They have a higher temperature compared to air and surrounding objects and serve as sources rather than “receivers”. But the walls of a heated room during the cold season emit energy in the infrared spectrum to the street. To see this background, just look at them through a thermal imager. It is especially bright in uninsulated areas and “cold bridges”.

It’s so easy to see how heat escapes through uninsulated walls Source rte-france.com

Natural convection is characterized by an upward flow of warm air and a downward flow of cold air. Of course, the temperature of the foundation cannot affect this process. It is important here to insulate the roof and ceiling so that they do not quickly “cool” the warm air.

Of the above three methods of transferring thermal energy, it is “thanks to” the thermal conductivity of structural materials that a cold foundation affects heat loss and heating costs of the house. And the thermal conductivity of reinforced concrete, from which the foundation is usually made, is quite high, so its low temperature is transferred to the walls and load-bearing partitions.

The air in the room cools due to the enclosing structures, which release heat to the environment. For the underground part of the foundation it is soil, for the base and walls it is air. Insulating the foundation reduces these losses.

Video description

Details about the heat loss of the building and the purposes of insulating the foundation are described in the video

But there is another function of thermal insulation of the foundation of a house - increasing the service life of the foundation. Building materials have such a criterion as frost resistance. Its numerical expression means how many freezing cycles (assuming water saturation) must pass before signs of destruction appear. Therefore, for regions with cold and long winters, insulation and waterproofing of the foundation is a prerequisite to ensure the strength and durability of the structure.

Technologies and materials

There are only two types of foundations that need to be insulated: slab and strip. For columnar and pile foundations, we can only talk about thermal insulation of the floor of the first floor and the insulation (basement) - a kind of screen that protects the subfloor. But piles and pillars do not directly insulate.

Plate

The technology for insulating a slab foundation is no different from the thermal insulation of concrete floors on the ground:

    a solid base of compacted soil;

    geomembrane as protection against capillary rise of groundwater;

    crushed stone-sand cushion to improve the bearing capacity of the soil and proper load distribution;

    roll waterproofing;

    sheet insulation (expanded polystyrene or EPS);

Eps is the best material for insulating slab foundations Source rmnt.ru

On our website you can find contacts of construction companies that offer foundation design and repair services. You can communicate directly with representatives by visiting the “Low-Rise Country” exhibition of houses.

The Swedes have slightly improved the technology and already at the stage of pouring the base they install a “warm floor” into the slab. In our country it is often done the old fashioned way - in a screed or under the finishing floor covering. Scandinavians are “boring” people and already know in advance where not only the partitions will be located, but also how the furniture will stand (one of the conditions for the correct operation of the “warm floor”). Our people have a different character - they are not only furniture, but also interior walls are often moved from place to place.

Strip foundation

Insulation of this type of base has a wider selection of materials and technologies:

    permanent formwork;

    fastening sheets of foam plastic or extruded polystyrene foam;

    spraying liquid polyurethane foam;

    filling of expanded clay.

Among foundation insulation materials, only one popular thermal insulation material is missing - mineral wool. When saturated with water, any type of water loses its thermal insulation properties. And although it not only easily absorbs, but also easily releases moisture, it is impossible to create conditions for its weathering for the foundation.

Places for foundation insulation Source anticafe-sandbox.ru

Technologies for insulating strip foundations

Each type of insulation has its own characteristics, which dictate the methods of its application.

This is the only method of insulation that is possible only at the stage of construction of a monolithic strip foundation. In fact, this technology can be called “two in one”, when the formwork made of thermal insulating materials remains as part of the structure upon completion of construction. Moreover, permanent formwork solves two problems - how to insulate the foundation of a house from the outside and from the inside.

Structurally, there are two types: block and panel. When pouring a strip foundation, shields are used. The blocks have walls and wide transverse bridges, which reduces the strength of the reinforced concrete base.

Ready-made kits have a set of polymer jumpers that can be used to adjust the width of the foundation Source visualizepicture.com

Such formwork is made from different materials, but most often the foundation of the house is insulated from the outside with polystyrene foam (regular or extruded).

In addition to the “clean” technology, there is a combined technology, when the slabs are not “connected” to each other, but are attached to removable formwork.

The combination of removable and permanent formwork provides increased strength for large volumes of concreting Source pobudova.in.ua

After backfilling the cavity near the underground part of the foundation, a “trough” is prepared for the blind area from compacted soil. And then according to the standard scheme: crushed stone, sand, waterproofing film, insulation (expanded polystyrene or EPS boards), formwork, reinforcement and concrete pouring. Instead of concrete, you can use paving slabs or gravel, but insulating the blind area as part of the general work is mandatory.

Insulation of the blind area will reduce the impact of soil heaving on the foundation Source de.decorexpro.com

Unlike the previous method, the existing foundation is insulated. Therefore, only external insulation is present. Work is carried out both during construction and during reconstruction or repair of a house.

Insulation during the construction of a house is much easier than during reconstruction Source volk1.ru

The most difficult work has to be carried out during repairs. Before insulating the foundation of the house from the outside, you need to dig out and clear the soil from the tape up to the heel. The stages then proceed in the following sequence:

  • Waterproofing is carried out - first a bitumen primer is applied, then strips of rolled materials are glued (soldered) from bottom to top with overlapping seams.
Note. It is better not to use bitumen mastics in combination with sheet insulation - they are “fluid” and do not provide reliable fastening of the slabs to the adhesive solution.

    Prepare an adhesive composition based on cement, and use it to secure the slabs to the foundation. In the above-ground part, additional fixation with dowels is not necessary - only on the base. Direct fastening of slabs using mechanical fasteners without an adhesive solution is unacceptable - the glue also serves as a “gasket” between polystyrene foam and bitumen, which is an aggressive environment for the polymer.

    After backfilling and making the blind area, the base is finished: a layer of adhesive is applied, reinforced with fiberglass mesh and plastered or tiled.

Video description

You can get acquainted with the features of polystyrene foam insulation technology in the video:

Insulation with sprayed polyurethane foam

Among all polymer insulation, sprayed polyurethane foam is the most expensive type. Its advantage is that the thermal insulation layer has no seams, and foamed polyurethane has very good adhesion to all types of building materials.

Application of polyurethane foam to a surface cleared of dirt is very quick. There are two types of materials: two-component and one-component.

In the first case, professional equipment is needed, the work of which is to supply both components under pressure to the working head, where they are mixed and foamed.

Single-component polyurethane foam is produced in liter aerosol cans, and even an untrained beginner can handle them correctly. But this technology is good for a small area of ​​work, or when it is necessary to apply a small layer up to 2 cm thick.

Spraying polyurethane foam is similar to painting with a spray gun, so it is better to cover the cladding of the house. Source ppuspb.ru

If the soils are dry, the water level is low and proper drainage work has been carried out, then waterproofing of the foundation and base need not be carried out - there are no seams, and the water absorption of hardened polyurethane foam is small (no more than 2%). When finishing the base with plaster, reinforcement is not necessary - there are no joints, like with foam plastic slabs, and, therefore, there are no prerequisites for cracks to occur.

In addition to the price, polyurethane foam has one more small drawback, which is a consequence of its advantage - good adhesion. When carrying out work on insulating the base, it is necessary to protect walls that already have finishing (or do not require it) - this is easier than cleaning off hardened foam.

Recently, this bulk material is rarely used for foundation insulation. Its use is limited by two factors: quite high, compared to polymer insulation, water absorption and thermal conductivity.

The thickness of bulk thermal insulation can reach 60 cm Source obustroeno.com

The first indicator lies in the range of 8-20% of the volume. Moreover, such water absorption is typical for “fresh” expanded clay - over time it becomes even higher. For comparison, for ordinary polystyrene it is no more than 4%. Therefore, waterproofing of both the foundation and the entire insulation layer is necessary.

It is impossible to ensure complete “tightness” of expanded clay, and it will take a long time to dry underground, wrapped in film - its use is not recommended in conditions of high seasonal rise of groundwater.

Thermal conductivity also does not meet modern requirements for thermal protection of buildings - 0.07–0.18 (W/m*°C) versus 0.02–0.04 for polyurethane foam, 0.03–0.04 for EPS/EPS. Therefore, the recommended thickness of bulk thermal insulation for our middle latitudes lies in the range of 40–60 cm.

The insulation scheme looks like this:

    dig a trench of the estimated width (or clear the cavity of the pit) to the heel of the foundation;

    lay a waterproofing film over the entire area of ​​the trench - foundation-bottom-wall;

    fill and level expanded clay;

    cover with film on top;

    pour a layer of sand;

    make a blind area.

Typical scheme for foundation insulation with expanded clay Source sevparitet.ru

The advantage of expanded clay is environmental friendliness and low price. Although, taking into account waterproofing and a large volume of materials, the cost of work in the end will not be so low. In addition, the base will have to be insulated using one of the above methods.

Conclusion

The choice of a specific material and how to insulate the foundation of a house from the outside depends on many conditions - construction or repair, dry or wet soils, depth of freezing and heaving, volume and budget of work, design and depth of the foundation. Therefore, this problem should be solved by professionals.

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 layer of foundation insulation.


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 on a bitumen basis 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 moisture that has 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. per 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, care should be taken to insulate 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

For normal operation of the building, it is necessary to insulate the foundation of the house from the outside and lay polystyrene foam under the blind area. The thermal insulation circuit solves several problems - expanding the frost-free zone, eliminating swelling, cold bridges and heat loss. The need for measures to eliminate swelling conditions (freezing + moisture + clay soil) is separately indicated in the standards SP 22.13330 (foundations), departmental VST, territorial TSN (for example, MF-97 for the Moscow region).

In order for an individual developer to insulate the foundation without errors, it is necessary to take into account that the owner’s expenses always consist of the construction estimate and the operating budget. Accordingly, by changing any of these points, you can automatically affect the other:

  • by refusing to insulate the blind area or foundation, the owner saves on the purchase of expanded polystyrene, but heating and repair costs increase;
  • By investing in thermal insulation, the developer increases initial costs, but automatically reduces operating costs.

By investing money in their own home, a young family receives an advantage during retirement in the form of significantly lower utility bills due to energy savings and no foundation repairs.

Heat distribution diagram near the foundation. It can be seen that the freezing line is moving away from the foundation.

Depending on the operating mode of the building, the developer’s budget and the type of soil, horizontal and vertical insulation contours solve different problems:

  • blind area - an EPS tape laid under it moves the freezing zone outward from the house, swelling is impossible in the soil layers adjacent to the foundation;
  • outer vertical surface of the tape - protection of waterproofing, elimination of cold bridges, reduction of heat loss through the floor/floor of the house, shifting the dew point outward for normal operation of the underground floor;
  • horizontal layer under the base of the MZLF - if the building does not have heating or is heated during periodic visits, to eliminate freezing of the soil underneath it is necessary to retain the heat of the subsoil with a continuous layer of polystyrene foam.

Important! A set of works to eliminate swelling must be carried out only on clay soils. However, heat loss in a complex base assembly with multilayer cladding and the adjoining of different structures made of different materials can only be prevented by external thermal insulation of the vertical surfaces of the foundation.

Materials and technology for foundation insulation

Given the existing variety of thermal insulation materials, foundation insulation is most often done with extruded high-density polystyrene foam EPS, XPS, Carbon SP from TechnoNIKOL, Penoplex Foundation. Unlike mineral, glass and ecowool, polystyrene foam retains its heat-insulating properties, even when completely immersed in water. For comparison, basalt wool loses 30% of its properties when wet and begins to slide off vertical surfaces under its weight. It is prohibited to rest concrete structures on soft insulation materials.

Insulation materials

To protect the foundation of a private cottage, the following thermal insulation materials are most effective:

  • polyurethane foam - marked PPU, sprayed onto the surface, also available in the form of slabs, density 50 - 60 kg/m3, thermal conductivity corresponds to 0.028 units, costs twice as much as expanded polystyrene;
  • extruded polystyrene foam - different designations from manufacturers, slabs of different sizes, density 35 - 45 kg/m3, thermal conductivity 0.03, cheaper than the previous option.

Insulation of the foundation with extruded polystyrene foam.

The polyurethane foam used to fill the seams of insulation is made of polyurethane foam. Therefore, when using Penoplex, EPS, the quality of the joints is higher than that of the main surface.

The main disadvantage of expanded polystyrene is its low chemical resistance - the material is dissolved by petroleum products. Therefore, it is not recommended to paste over concrete surfaces treated with bitumen mastics, fused with roll materials having a bitumen layer. It is better to use polymer mastics, membranes or polyethylene films. Polyurethane foam is inert to petroleum products, acids, alkalis and salt solutions.

Budget foam plastic PSB-S has a density of 15 - 25 kg/m3, thermal conductivity of 0.04 units, and vapor permeability of 0.05. This insulation is used in the following cases:

  • outer layer of vertical crushable insulation;
  • permanent formwork for a low grillage (lower horizontal deck).

In the first case, insulation is necessary to protect the main layer of heat insulation. In the second option, the foam plastic remains after the grillage is poured under the reinforced concrete structure, and is crushed by the soil during swelling, so that heaving forces cannot tear the grillage beams away from the pillars or piles, the heads of which are embedded in the structure.

Technology overview

Foundation insulation is carried out according to different schemes depending on the operating mode and design. Protection against swelling is necessary for columnar, strip and slab foundations. Heaving forces have practically no effect on the piles, however, with a low grillage on bored or screw piles, the beams must be positioned at least 10 cm above the ground.

Scheme for insulating the foundation and outside blind area for a house with constant heating.

There are three main operating modes at home:

  • constant heating - insulation reduces heat loss, expands the zone of non-freezing soil around the building and protects the foundation from the effects of negative temperatures;
  • heating is completely absent - eliminating heat loss in this case is pointless, however, it is necessary to preserve geothermal heat under the building to prevent soil freezing, so the blind area + the entire perimeter of the garden house under the sole is insulated;
  • heating is turned on periodically (baths and cottages) - since episodic heating is present, it is necessary to reduce heat loss in the ceilings and floors, the outer surface of the grillage, strip, slab and blind area is insulated; when there is no heating, there is a need to preserve the heat of the subsoil, so the entire perimeter of the house under the sole is insulated foundation.

In garden houses without heating, laying polystyrene foam at the level of the base of the foundation is not always economically profitable:

If the depth of the pillars or MZLF is within 40 cm, it makes sense to make a pit, since the fertile layer will still have to be completely removed in order to make floors on the ground.

If the strip or columnar foundation lies deeper, excavation work can be avoided by laying insulation according to a different scheme:

  • under the blind area - the perimeter of soil freezing moves away;
  • under the base of the foundation – protection against swelling;
  • on the inner surface of the tape + under the floor along the ground - conservation of geothermal heat under the entire foundation structure.

If for some reason it is impossible to fill the pit openings with non-metallic material that does not contain clay and, accordingly, frost swelling, instead of the standard insulation of the outer surfaces of the strip foundation, a crush-sliding thermal insulation scheme should be used:

  • pasting external concrete vertical surfaces with high-density polystyrene foam;
  • covering it with polyethylene (attached only in the base part);
  • installation of low-density polystyrene foam PSB-S close to the film without fastening (pressed with backfill material).

This option is especially relevant for deep-laying belts. The contact area of ​​the side surfaces of the belt with clay soils is enormous, and the pull-out loads are very significant. When heaving forces occur, the soil crushes the foam and moves it upward along the slippery film. The main layer of insulation is not harmed; after the spring thawing of the soil, the outer layer moves down again.

Important! Insulation is only one method of eliminating swelling in a set of measures. Therefore, drainage and nonmetallic materials in the underlying layer and backfilling of sinuses cannot be canceled.

In classical technologies of monolithic foundations (slab, strip, pillars), a concrete screed is used to reduce the lower protective layer of concrete, level the base, and eliminate leaks of cement laitance from the concrete at the time of pouring.

If a building for seasonal, periodic operation is insulated with a layer of expanded polystyrene around the entire perimeter of the pit, then there is no need to make a concrete footing. This allows us to slightly reduce the construction budget.

Errors in foundation insulation

Due to lack of experience, individual developers often make mistakes when insulating foundations:

  • cold bridges - the thermal insulation contour must be continuous, the seams must be foamed, the joints of the slabs must be displaced in the case of a multilayer contour in adjacent layers;
  • the use of low-density materials - PSB-S is allowed only for the lower deck of the grillage, the outer layer of crushable thermal insulation;
  • violation of thermal insulation schemes - for basements, MZLF buildings with constant heating, it is necessary to insulate the tape from the outside, without heating and when the heating is periodically turned on - from the inside;

Cold bridges, which negate the effectiveness of insulation work, usually occur at the junction points of the base elements:

  • lack of lateral vertical thermal insulation along the perimeter of the floor screed on the ground;
  • uninsulated concrete preparation;
  • absence of polystyrene foam on the upper horizontal edge of the protruding base;
  • incorrect combination of basement insulation and façade insulation.

Errors in pairing the insulation of the base and façade.

Important! It is impossible to correct the cold bridge created as a result of facing the facade with brick, the bottom row of which is installed directly on the protruding plinth.

Thus, despite the fact that it is recommended to mount the insulation on the outer surfaces of the foundation, this scheme is correct only for dwellings with a constant heating mode. In garden houses, thermal insulation is made along the inner edges of the tape. The blind area is always insulated; crushable thermal insulation is usually necessary for deep-lying tapes.

Insulating the foundation of a house from the outside is no less important than the walls and roof, because the uninsulated base of a building allows ≈ 20% of thermal energy to pass through to the street. And these are extra costs for heating and energy. Uninsulated walls are more susceptible to the destructive power of rain, wind, frost and sun - moisture, turning into ice, breaks concrete, and microcracks cause the appearance of “cold bridges”, accelerating the transfer of heat from the house to the outside. Ultraviolet light and wind only help the destruction of concrete or brick.

The benefits of insulation

Microcracks will not always remain small; they will increase over time, thereby increasing the risk of failure. Total insulation of the foundation from the outside is a shift of the dew point from the wall material into the insulator, which helps maintain the technical and physical characteristics of concrete. For example, when the ground freezes by 15%, the rupture of water molecules can cause a soil shift of 30-35 cm, which can deform it. In hard rock, these risks are reduced, but do not disappear, so the depth of the foundation of the house is calculated based on the freezing point of the soil in the region. The material is attached vertically and horizontally, and it is advisable to do this in 2-3 layers.

Insulation of the outside of the house is carried out not only for heated rooms. Even in the absence of a basement, insulating a shallow strip foundation together with a plinth reduces heat losses by 15-25%.

For those who like to save money: with proper insulation of the foundation and basement, the floor of the lower floor does not need to be insulated.


A cold foundation creates conditions for easy penetration of air from the street into the house. Therefore, the floor level is immediately raised 20-30 cm above the ground. If it is not insulated, the rooms in the basement and the basement walls will be constantly damp and cold. The benefits of insulation are manifested in the following:

  1. The overall heat loss is reduced, and energy costs during the heating season are reduced.
  2. The heaving soil under the house does not deform the foundation when thawing or freezing.
  3. Prevents condensation and fungal diseases from appearing on the basement walls.
  4. The service life of concrete structures increases.
  5. An additional advantage is the protection of the waterproofing layer from damage.
  6. Shift of “cold bridges” closer to the outer surface.

The issue of insulation is solved in the same way: before pouring it, permanent formwork is installed around the perimeter of the trench, and it is advisable to use polystyrene foam for it, which will be an additional warming layer. Then, after pouring, the foundation will be in a “bag” of polystyrene foam and will be insulated from the outside and inside.

How to properly insulate

  • The beginning is digging a trench along pre-marked lines, marked with a cord tied to pegs around the perimeter of the foundation. If the volume of work is large, it is easier to rent an excavator, and it is better to trim the walls of the trench with a shovel.
  • A sand-crushed stone cushion with a thickness of ≈20 cm is placed on the bottom and compacted with moisture.
  • Vertical permanent formwork made of polystyrene foam slabs is attached to the outer and inner walls of the trench. The gaps between the slabs are filled with construction foam - this will help to avoid the foundation from being moistened by groundwater.
  • A reinforcing frame is created. For the base, reinforcing rods of 10-16 mm are used, which are tied together with soft steel wire or fastened with special plastic clamps. Reinforcement neutralizes the effects of compression and bending forces from the soil and the weight of the building.

  • Concrete solution, prepared manually or purchased from the manufacturer, is poured into the trench. Ordering several tons is easier and faster than preparing it in a concrete mixer. It is advisable that the foundation be poured in one go. It takes about 28 days to set and harden to the stated strength, during which the surface is watered several times so that the concrete hardens evenly outside and inside.
  • Waterproofing is installed - this can be done by attaching roofing felt or polyethylene to the walls.
  • When insulating the external foundation with your own hands, it is important not to forget about the thermal insulation of the internal walls of the foundation. The insulation also extends to the base, so there is no need to create anything additional – it is enough to carry out decorative finishing work on the external walls.

This method is good for insulating a shallow foundation without a basement or basement. If the house has a basement, then the process looks different: first, a foundation pit is dug with an excavator, and the foundation is made of reinforced concrete blocks. If it is filled with concrete, then wooden removable formwork is built. It is mounted at a distance of 30-40 cm from the walls of the pit, so that after pouring and hardening of the solution it can be disassembled. The space between the concrete and the pit is covered with soil - this is called backfill. Expanded polystyrene will not work here - the weight of the solution will crush it.

When arranging wooden formwork, it is possible not only to insulate the outer walls, but also to lay (or apply) a layer of waterproofing. It can be installed immediately if a block foundation was built, and only after four weeks when pouring concrete. When using liquid waterproofing (bitumen, tar, mastic), the room must have a positive temperature. Rolled materials are secured with dowels or the same mastic.

The question of how to insulate the foundation from the outside is solved by using extruded polystyrene foam (penoplex). It has high technical characteristics. Moreover, the depth of insulation does not depend on the thickness of the penoplex layer, since the slabs can be built on top of each other (in a checkerboard pattern). The thickness of the thermal insulation layer should increase as it approaches the ground surface. For central Russia, foam slabs up to 8 cm thick are laid up to 1-1.5 m from the ground surface, then 3 cm can be used. On the north side, slabs 10 cm thick are attached to a depth of 1-1.5 m, below - 5 cm.

Advantages of penoplex:

  1. High levels of heat and sound insulation, strength and moisture resistance.
  2. Neutral material, so it is not damaged by rodents, fungal organisms and insects.

Expanded polystyrene is attached in several ways:

  1. Warm-up method. To do this, using a construction hairdryer, heat the waterproofing material until it begins to melt and, while it is still hot, press a polystyrene foam slab against the wall.
  2. If the walls are uneven, then the slabs are attached with mastic or construction cement-polymer adhesive. The mastic is applied pointwise with a brush; after gluing, the fastening does not need to be duplicated with umbrella dowels.

    In both the first and second options, the joints are filled with polyurethane foam.

The last stage is backfilling the trench. The soil is mixed with sand in proportions 1:1, the gap between the foundation and the foundation pit is filled with this mixture, and every 20-30 cm the sand is watered and compacted. A blind area is made on top.
backfilling

Insulation of the foundation of a wooden house

The base is a monolithic continuation of the base, located above the ground surface, so it also needs to be insulated and protected from moisture. According to the rules, the subfloor level on the first floor should be at the same level as the top of the plinth. Therefore, insulating the latter will prevent the walls from freezing, while simultaneously making the floors of the first floor and the ceiling of the basement warm. Small additional costs are offset by savings on heating.

A house made of logs or timber may have a wooden base, and penoplex is not suitable for its insulation, since polystyrene foam does not allow air to pass through. This is important for long-term operation, because such a house suffers from condensation in the basement.

It is recommended to insulate such a base using polyurethane foam. This is a new synthetic insulation, it is applied by spraying, and the polyurethane foam expands and fills all the pores, cracks and joints between materials. Its good adhesion helps the foam adhere to any surface.

Algorithm for insulating a wooden base:

  1. First, a wooden sheathing is constructed - after applying polyurethane foam, it is sheathed with decorative finishing material, for example, siding or clapboard. Between the slats, the lathing is filled with polyurethane foam using a sprayer, which, expanding during hardening, forms a continuous durable layer up to 7 cm thick. And this is enough - the thermal conductivity of the material is 0.019-0.035 W/(m · TO).
  2. The hardened excess foam is cut off with a knife or carpenter's cutter, after which the surface is covered with decorative building materials.

This method is much simpler, but is only suitable for wooden bases. The general principles of insulating a house from any building materials are clear and simple, so that it can be done independently, without using the paid services of specialists.

Today the topic of how to insulate your home is more relevant than ever. In order not to waste money by warming the soil, it is easier to once thoroughly insulate the most consumable part of the building - the foundation and the basement of the walls. High-quality insulation of the foundation from the outside will require certain costs, but, fortunately, most of the work can be done with your own hands. If you save, it will be on someone else’s services, and not on the quality of the material used.

Work on insulating the foundation of a house from the outside by an amateur

To get rid of the troubles associated with hypothermia and freezing of the foundation system, you can use several options for installing thermal insulation:

  • Increase the efficiency of the drainage system and thereby reduce the level of moisture in the soil outside the building. This will automatically reduce the thermal conductivity of the soil adjacent to the foundation walls and reduce heat loss;
  • Use the classic method of insulation with your own hands, lay insulation on the basement sections of the walls, cover the foundation blocks with foamed heat-insulating material;
  • Perform thermal insulation of the joints between the floor slabs of the basement, blind area, and place the backfill thermal insulation mass in the foundation cavities;
  • In the case of insulating a columnar foundation with your own hands, it is necessary to additionally cover the inlets with heat-insulating material or masonry that retains heat in the space under the building.

Do-it-yourself foundation insulation

Conventionally, the insulation of the foundation plinth from the outside can be divided into two groups according to the scope of work: the first is to ensure thermal insulation due to the soil, the second is to ensure heat savings by laying insulating materials on the structure of the foundation and wall plinth.

Loose-fill forms of thermal insulation

Ground thermal insulation has a number of characteristics that, at first glance, are not obvious, but, nevertheless, are very important for effective insulation of a house:

  1. Skillfully organized drainage from the surface of the soil adjacent to the blind area of ​​the foundation of the house makes it possible to reduce the water saturation of the soil several times, which means that the thermal conductivity of the top layer of soil, 50 cm thick, which makes the main contribution to heat losses, will decrease by at least half. This will be much cheaper and more effective than covering the blind area with a huge amount of polystyrene foam;
  2. Effective drainage of accumulated groundwater, its removal from under the base of the building and adjacent soil layers outside, correctly laid barriers and insulating membranes at the base of the foundation can reduce heaving and water filling of the soil by 3-4 times;
  3. The most effective of the soil thermal insulation methods is the backfill form of insulation of the foundation structure. If polystyrene foam materials glued to the concrete surface of the foundation can be destroyed, chipped, or crushed by the ground in very cold weather, then backfill forms are practically insensitive to such problems.

Foam glass is considered one of the most effective fill-type heat insulators. The material has high hardness, comparable to the hardness of concrete, and excellent thermal insulation characteristics. If you make a ditch or trench outside with your own hands to the depth of the foundation and fill the formed cavity with foam glass granules, this will sharply reduce the heat loss of the foundation, improve water drainage, since the backfill layer plays the role of a sponge, and increase the stability of the foundation. In addition to ordinary granules, manufacturers suggest using compositions of glass granules and bitumen filler to insulate the surfaces outside of foundation blocks.

The currently used expanded clay or vermiculite backfills are not so effective in insulating the foundation of a house, but due to the low price of the material, the width of the insulating layer outside the foundation can be increased several times.

Traditional methods of thermal insulation and insulation of the foundation of a house

If you need to insulate the outside of foundation blocks in the shortest possible time, instead of traditionally gluing polystyrene foam boards on the outside of the foundation base, insulate the concrete surface with polyurethane foam. A layer of foamed polyurethane foam is easily applied with special equipment to the most humpbacked and uneven surface of concrete blocks.

If it took days and weeks to lay polystyrene thermal insulation, then applying polyurethane foam even with your own hands can be done within one working day. Laying a polyurethane foam-based insulation system to a depth of 30 cm to 2 meters creates comfortable conditions for maintaining the performance characteristics of insulating materials. Firstly, there is no ultraviolet radiation from the sun, and secondly, a minimal temperature difference is maintained. The cost of such insulation is slightly higher than traditional slabs, but it can be used externally as a means of insulating any, even the most complex and problematic foundations.

For relatively flat surfaces of external foundation walls, tile thermal insulation materials are most often used. They are used to assemble the insulation of the outer walls of the foundation, basement and blind area, as in the video:

Installation of insulating material outside can be done either on a layer of bitumen waterproofing or without it. In the first case, the blind area, the outer surface of the foundation walls and basement floors, is dismantled, mechanically cleaned of all dirt, mortar buildup, and unevenness, and then treated with a waterproofing compound. Depending on the characteristics of the soil, waterproofing can be strengthened with your own hands by sticking roll insulation of polymer films.

Typically, the manufacturer of insulation materials recommends plastering and leveling the walls from the outside, thereby ensuring the most tight and uniform fit of the insulation system to the foundation walls. After waterproofing the outside of the foundation walls, the structure is faced with foam polystyrene slabs. To attach the slabs from the outside, it is most convenient to use bitumen mastic or acrylic glue.

A metal mesh is mounted outside the laid heat insulator. A layer of protection can be applied on top of the laid thermal insulation cake. Most often, this is a durable waterproof plaster that protects the surface of polystyrene foam from the destructive effects of soil or mineral backfill. In the same way, insulation is laid on the basement surface of the walls and on the blind area.

If you need to insulate a columnar or pile foundation, you can reduce heat loss by filling the soil around the supports to a depth of 30 cm with a dense, heavy mass based on foam glass. In this case, the main part of the insulation should be carried out on supports located outside the building. This type of filling is best combined with a viscous and dense mass like resin or roofing bitumen. Thus, the amount of moisture entering the base of the supports is sharply reduced, and the level of soil freezing outside the supports is reduced.

In addition to insulating the supporting elements, it is necessary to thermally insulate the space under the building. The simplest method is to hang a false plinth on the foundation grillage. The heat emanating through the bottom of the building will partially warm the piles or support pillars themselves and part of the air space underneath. If the inside of the columnar foundation is covered with a layer of expanded clay, and the false base covering the structure from the outside is made in the form of sandwiches made of wood and polystyrene foam, then an acceptable level of insulation can be achieved.

Conclusion

When carrying out measures to insulate a building, relatively little attention is paid to such forms as deep drainage of groundwater, drainage and drying of the soil, and improvement of the thermal insulating properties of the earth adjacent to the foundation structure. It is believed that it is easier and faster to insulate the foundation from the outside on your own by gluing sheets of foam material or applying a foamy polymer mass. However, the use of ground thermal insulation can be no less effective than the use of polymer thermal insulators.

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Insulation of the foundation of a wooden house from the outside

Insulating the foundation of a house performs several functions: it not only prevents heat from escaping through the base of the house and reduces heating costs, but also acts as waterproofing and protects the foundation from frost heaving of the soil. Without thermal insulation of the foundation, the first floor of the house will be cold and damp. Practice shows that insulating the foundation of a wooden house from the outside solves all these problems. It is much more effective than insulating only from the inside. In some cases, thermal insulation of the foundation is done both from the inside and outside.

Why is it better to insulate the foundation from the outside?

Experts believe that this option is preferable for several reasons.

It is recommended to insulate the foundation from the inside only if the basement has good ventilation. Otherwise, the humidity in the basement will increase, in addition, the inner layer of insulation shifts the dew point, because of this the entire base is exposed to moisture and cold. This reduces its service life and leads to rapid destruction.

Wooden houses are usually placed on a columnar, pile or strip foundation. These types differ in their design, which means their insulation is done differently.

For thermal insulation of any type of base, extruded polystyrene foam (EPS, penoplex) is used. It is durable, has a long service life, does not emit toxic substances, is resistant to compression loads, does not allow water to pass through, and does not grow mold or moss. It is easy to use, attached to the foundation with special glue or with the help of umbrellas; the foam boards have a convenient connection to each other.

Strip foundation

First, they dig a trench all the way to the bottom of the foundation. Its width is 80-100 cm, since the blind area is also insulated at the same time. If the foundation is of a recessed type, then the first 40 cm deep trench is dug to the width of the blind area, and then, to save effort, you can make it 50 cm wide.

If the house was built some time ago, cracks may appear in the concrete. They are covered with a mixture of cement and construction adhesive if the cracks are small. Larger damage is repaired with cement mortar.

The next step is waterproofing. To do this, the surface of the foundation tape is covered with bitumen mastic, onto which roofing material is glued. The sheets are glued overlapping, the seams are additionally coated with mastic. More modern roll materials are also used, such as self-adhesive roll waterproofing.

After this, the insulation is glued. Although penoplex is often attached to dowels, it is still better to give preference to glue or liquid nails - they do not violate the integrity of the sheets. How to insulate a strip foundation with polystyrene foam, watch the video:

The joints between the sheets are foamed with liquid foam.

After installing the insulation, geotextiles are glued onto it. It will reduce the effect of soil heaving on the heat-insulating layer.

Next, the trench is backfilled to the level of the blind area. Sand and small crushed stone are poured under the blind area in a layer of 0.15-0.2 m, and the cushion is carefully compacted. This layer will protect the blind area from loads arising from soil movement. A layer of dense insulation is placed on top. The same penoplex is suitable due to its resistance to compression loads. Concrete is poured on top; it can additionally be reinforced with mesh.

Attention! To reduce the effect of frost heaving, the insulation layer is placed at the level of the base of the foundation. The most effective combination of penoplex insulation up to the level of the walls in combination with insulation of the blind area at the level of the sole.

Pile foundation

How to insulate the foundation of a wooden house on stilts? For a pile foundation, as for a columnar foundation, a fence is built - an imitation of a base, closing the space between the piles. This will already reduce heat loss to some extent. For effective thermal insulation of a pile foundation you need:

  • arrange a basement,
  • insulate it inside and out,
  • insulate the floor.

You can build a thin brick wall around the perimeter, or you can use slab materials that are attached to the sheathing. If you choose the option with a brick wall, you need to pour a shallow concrete strip 20 cm thick on which the wall will be built. It is not necessary to use ceramic bricks; you can take foam blocks or foam glass.

Important! The space under the floor should not be sealed. After installing the intake, vents must be made in it - ventilation holes measuring 10-15 cm. They are placed evenly on all sides of the house so that they are opposite each other.

To fasten panels or slabs, a sheathing is made from a metal profile or wooden blocks. For example, DSP can be used as outer cladding. There are already insulated facade panels that perform decorative and thermal insulation functions.

A shallow trench is dug under the casing, into which a layer of sand (2-3 cm) is poured, expanded clay is placed on it, and the trench is covered with earth on top, so that there is no gap between the soil and the casing.

The video shows the structure and insulation of the false base:

To insulate a pile foundation, use

  • expanded polystyrene,
  • Styrofoam,
  • foam glass in blocks,
  • liquid penoizol (urea foam).

The first two options are most often used. Foam glass is too expensive for a private home, and liquid foam insulation requires special equipment or the work of specialists, which is also expensive. It’s easier to insulate the foundation of a wooden house with your own hands using polystyrene foam or expanded polystyrene from the outside. The main thing is that the material does not absorb water, so mineral wool will not work here. The foam is glued to the adhesive foam; for reliability, you can use additional wooden planks, which are attached with self-tapping screws to the sheathing through the foam.

Important! It is advisable to attach polystyrene foam or polystyrene foam to the guides, and not between them. In this case, there will be no gaps or cold bridges, since the thermal conductivity of wood, and especially metal, is greater than that of foam plastic.

You can insulate a pile foundation with polystyrene foam or EPS from the outside or the inside. If this is done outside, then the insulation is attached before finishing. If the finishing is already attached to the base, for example, if these are facade panels or DSP boards, then the insulation is mounted from the inside.

Floor insulation

To insulate the floor in a wooden house on a pile foundation, I usually use mineral wool, basalt wool, expanded polystyrene, foam plastic, and liquid insulation.

Thermal insulation is done during the construction and installation of the floor as follows:

  1. They make a subfloor on which the insulation will lie.
  2. A vapor barrier and windproof layer is first placed on the sheathing.
  3. Then they put insulation.
  4. Vapor barrier and waterproofing are placed on top.
  5. After this, a finishing floor is constructed.

The layer of mineral wool must be at least 10 cm. If it is necessary to lay wool in two or more layers, this is done in a checkerboard pattern (so that the seams do not coincide). The video shows floor insulation in a house on a pile foundation.

For waterproofing, you can use glassine, polyethylene, isospan, and wind- and moisture-proof film. Polyethylene is the cheapest option, but it is not the best.

Important! In a wooden house on a pile foundation, it is imperative to treat all wooden floor elements with an antiseptic.

The insulation of a columnar foundation differs little from the insulation of a pile foundation; the same materials and techniques are used.

Conclusion

Insulating the foundation helps not only retain heat and reduce heating costs, but also protects the foundation, makes it more durable, performs a waterproofing function, and prevents dampness in the house. Wooden houses are usually made on a strip or pile foundation, which can be simply insulated with your own hands.

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Insulating the foundation from the outside with your own hands

Any of us wants to have a warm and comfortable home, but not everyone thinks that in order for the house to be warm, it is necessary to insulate not only doors, windows, balconies, but it is better to start insulation from the foundation. By insulating the foundation of a log house, you can significantly reduce heat loss and reduce energy costs in the winter.

Why is thermal insulation needed, and its types.

When building a wooden house or bathhouse, one of the most important tasks is the thermal insulation of the foundation, which can be both external and internal.

Each person decides for himself when and with what materials to insulate his home

Let's consider the advantages of external thermal insulation:

  1. Regardless of the material used for thermal insulation and the design of the foundation, any external thermal insulation prevents the penetration of low temperatures into the room, that is, it “protects” the foundation from freezing;
  2. savings (heating bills are reduced by about a third);
  3. extends the service life of communications;
  4. extends the service life of the foundation of a wooden house;
  5. protects against groundwater and moisture entering the foundation (foundation waterproofing);
  6. protects the foundation (lower and basement parts) from seasonal temperature changes.

Insulation cake diagram

Sometimes it is impossible to insulate the foundation from the outside with your own hands, then you should insulate the foundation from the inside.

Let's consider the advantages of insulating the foundation from the inside:

  1. forms the microclimate of the basement and the entire house;
  2. protects from groundwater;
  3. prevents condensation accumulation.

But internal thermal insulation also has a number of negative aspects, these are:

  1. it does not prevent the foundation from freezing;
  2. As a result of temperature changes, the foundation may deform, cracks may appear, and the soil may swell.

Let's consider how to carry out work on internal insulation of the foundation.

There are various materials for carrying out such work, these are: polystyrene foam or polystyrene foam and polyurethane foam.

You need to know how to work with each of them correctly.

Polystyrene foam is a fairly cheap material, but when working with it you must remember that it crumbles, it must be cut out, and then glued with a special mastic. It will take a lot of time to install it.

Polyurethane foam is easy to work with. It is used to insulate basements and subfloors. Available in the form of a spray can.

It is used by spraying the contents of the can onto the surface that needs thermal insulation (in this case, the basement floor). They also spray it on part of the basement wall. If they want to more reliably protect the basement from cold and moisture, then polyurethane foam is sprayed on both the floor and the ceiling. After it hardens, it is necessary to carry out finishing work on the walls and floor. First they are puttied, sanded, and then veneered. Drywall may also be suitable for this.

Insulation of the foundation. Necessary materials. Methods of thermal insulation.

For external thermal insulation of the foundation, the following are used: polystyrene foam, polystyrene foam and polyurethane foam.

In order to insulate the foundation from the outside with your own hands, follow these instructions, which will tell you what materials will be needed and what materials should be used correctly.

This is what an insulated foundation with polyurethane foam looks like

The method of working with polyurethane foam is the same as when carrying out internal insulation, with the only difference being that in this case it is necessary to completely expose the foundation of the house. For this:

  1. It is necessary to dig a ditch along the perimeter of the house, the depth of which corresponds to the depth of the foundation, and the width should be approximately 0.50 m.
  2. Clear the external foundation from the ground and level it if necessary.
  3. It is necessary to wait until it dries, clean the surface of the foundation of dust and use bitumen mastic and roofing material to waterproof it.
  4. For more reliable protection from moisture, the joints of the insulation must be filled with special foam.
  5. To protect the foundation from groundwater, the top sheets of insulation are raised 30–40 cm above ground level.
  6. After the work described above is completed, sand is poured onto the bottom of the dug ditch (layer thickness 10–15 cm), and the remains of the insulation are placed on top and sprinkled with gravel (50–60 cm).
  7. Then the top is sprinkled with earth or sand, or poured with concrete (blind area).
  8. You can also then lay a mosaic of ceramic tiles or marble.

After the advent of polystyrene foam and polystyrene, expanded clay began to be used less and less for thermal insulation of houses.

The method of working with expanded clay is almost the same as with polystyrene foam, but there are differences:

  1. when insulating the foundation with expanded clay, it is necessary to dig a wide ditch - about 1 m,
  2. then lay down the waterproofing and cover it with a fairly thick layer (poor thermal conductivity) of expanded clay, or rather with its granules.
  3. Next, roofing material is laid as waterproofing and sprinkled with a layer of sand or earth.

Types of foundations and methods of their insulation.

In order to correctly carry out external foundation insulation work with your own hands, you need to know what types of foundations exist and how to properly insulate them.

Let's consider the existing types of foundations for a wooden house (shallow, columnar, monolithic, strip, pile) and methods of their insulation.

This foundation is made of brick or concrete.

A shallow foundation can be of a strip or slab type, so the shrinkage of such a structure is uniform.

When insulating such a foundation, it must be borne in mind that if the width of the insulation is greater than the depth of soil freezing, then under the insulation (which is located at a distance of 1-1.5 m), a zone of soil is formed that does not freeze.

A columnar foundation is made of pillars dug to a depth of 2 m (below the freezing depth). The house is subsequently placed on the upper ends of the pillars and therefore their level should be the same (40 - 50 cm) - this is the floor level of the house. This distance is necessary to avoid getting wet and subsequently rotting the wooden house.

There are two technologies to fill a columnar foundation:

  1. They dig a hole 40–50 cm larger than the required post, make formwork, install reinforcement or frame, and fill it with concrete. After drying, remove the formwork. This is how a monolithic reinforced concrete pillar is made.
  2. Using a special drill, you can independently drill a widened well and fill it with concrete.
  3. Read more in the article: columnar foundation with grillage.

A columnar foundation is suitable for building buildings on slopes, but houses with such a foundation cannot be built on groundwater. It is difficult to insulate such a foundation; more precisely, you will have to make a thick base, and you will have to carefully insulate the wooden floor.

A screw foundation is almost the same as a columnar foundation, but instead of monolithic pillars or metal pipes, they use piles that are screwed into the ground. Insulation of such a foundation is also problematic.

A monolithic foundation is a homogeneous slab under the entire house, but it should be noted that there will be no basements in the building. Houses with such a foundation are called floating, since under the influence of groundwater the entire house moves and does not sag or settle. Monolithic foundations can be shallow or deeply buried. For a shallow foundation, only the top layer of soil should be removed (that is, shallowly buried), and for a deeply buried foundation, you need to dig a pit.

A strip foundation for a log house is a closed structure that runs under all the walls of the house. Such a foundation is suitable for any type of structure that will have a basement in the future. Such a foundation can be made monolithic or made of concrete blocks. You can make a monolithic strip foundation yourself, but keep in mind that it is very massive for wooden houses.

Useful tips

  • For external and internal insulation of the foundation, it is better to use polystyrene. Compared to other insulation materials, it is more expensive, but more reliable, since it completely covers the surface without seams or gaps.
  • To insulate baths, it is better to use foil penotherm as insulation, since a room lined with this material looks impressive and comfortable.

And in conclusion

Insulating the foundation from the outside with your own hands is not an easy task, but it is a feasible task and anyone can do it.

If you want to save time and costs on this work, then first find out the prices for this or that building material, take into account the type of foundation, and only then purchase the required building material in the required quantity.

Also, after you insulate the foundation yourself, do not forget to insulate it from the inside (for better heat retention in the house). To do this, also spare no expense and purchase quality material.

It is better not to delay or neglect the work described above. If you live in a region where there are no seasonal temperature changes, then you also need to carry out work on insulating the foundation. This will ensure thermal insulation of the foundation and prevent cold air and moisture from entering the house.

And then both the private house and the bathhouse will be cozy and comfortable. Also, the microclimate in the house will be preserved.

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How to insulate the foundation of a house from the outside with your own hands with a diagram

An important part when building a house is the foundation, as it forms the foundation of the house. Reliability and strength are the main purpose of the foundation. You should not skimp on quality, because the service life depends on the material from which it is made. The climate in the country, especially in winter, is not the warmest.

Cold weather creates cracks in the foundation, thereby damaging it. To prevent this from happening, you should take care of the foundation of the house, namely, insulate the foundation and brick base protruding above the ground from the outside, this will prevent freezing and waterproofing. Methods include: foundation insulation with polyurethane foam, polystyrene foam, penoplex, thermal panels.

To perform such work, it is better to turn to professional specialists with skills in the field and the availability of ready-made equipment, but if you are sure that you can handle the job, you can do it yourself (available videos with instructions will help you understand this technology).

Many people, having insulated the lower part of the house from the inside from the cold, do not take into account that the influence of water and cold contributes to the formation of microcracks, which will subsequently lead to undesirable consequences.

Insulation from the outside is much better, because the material from which the foundation is made will protect against freezing and provide waterproofing. Technoplex extruded insulation is extruded polystyrene foam (XPS), suitable for insulating the base from the outside.

For more information about insulation with Technoplex, watch the video.

Types of foundations

  • Tape
  • Columnar
  • Slab
  • Pile

Choosing insulation

Expanded polystyrene or polystyrene foam

  1. Sound, heat and waterproofing.
  2. The thickness of the layer of this insulation is 5 kg.
  3. Great strength and easy installation.
  4. Affordable price.
  5. Suitable for insulating a wooden house from the outside.
  1. Polystyrene foam is not suitable for mounting the base part due to its flammability.
  2. Moisture absorption.
  3. Requires additional structures, which leads to additional costs.

How to choose foam?

Polystyrene foam is a plastic material, the bulk of which is air. It is because of the large amount of air that foam has good thermal insulation.

Polystyrene foam can be pressed or unpressed. The main criterion in choosing polystyrene foam is flatness. High-quality foam feels elastic and soft to the touch.

Expanded polystyrene is a universal insulation material in all respects. Despite the fact that the production of expanded polystyrene began 60 years ago, it is still popular and has no analogues in the Russian Federation.

Step-by-step do-it-yourself polystyrene insulation technology:

  1. Cleaning walls from dust and dirt.
  2. Preparing the primer.
  3. Apply primer to walls using a roller or brush.
  4. Installing the starting strip on the plinth.

Polyurethane foam

  1. Good adhesion.
  2. Minimum cost.
  3. Does not depend on weather conditions.
  4. Efficiency.

Let's move on directly to the insulation itself.

  • When insulating the outside, an excellent material is expanded polystyrene (foam). First, waterproofing is carried out (bitumen mastic can be used), and then polystyrene foam boards are glued.
  • If you decide to insulate with polyurethane foam, then it is enough to spray liquid over the surface from a special spray device.

Penoplex

  1. Easy installation.
  2. Resistance to cold and vapor permeability.
  3. Strength.
  4. Unlike expanded polystyrene, penoplex does not absorb water, providing waterproofing.
  5. Strength.
  6. Penoplex is an environmentally friendly material.
  1. High cost.
  2. At high temperatures, penoplex melts.

What are foam boards suitable for? Penoplex slabs are well suited for insulating baths, basements, and country houses. Penoplex provides good thermal protection, thereby saving heating and air conditioning costs.

Thermal panels

Advantages:

  1. Strength.
  2. Moisture condensation.
  3. Preventing cold air from entering the house.

Disadvantages: The most expensive, compared to the above.

Insulation of strip foundation:

  1. Compacting the trench and filling it with a layer of sand (10-15 cm).
  2. Pouring a layer of concrete (3-5 cm).
  3. Waterproofing is applied to the cement layer and insulation is laid (insulation can be done with polystyrene foam, penoplex, expanded polystyrene).

Insulation technology for columnar foundations.

First you need waterproofing. After waterproofing, you can begin the insulation itself:

  1. The first thing to do is to mount the metal frame.
  2. The metal frame is sheathed with metal profile sheets.
  3. Attach insulation boards inside the frame.
  4. Fill the remaining free space with expanded clay.

Insulation of a pile foundation

  1. The first step is waterproofing so that metal elements do not collapse over time and wooden elements do not rot.
  2. Then the base frame is erected.
  3. Install insulation inside the base (you can insulate it with polystyrene foam, penoplex, expanded polystyrene).
  4. Secure the panels to the plinth.
  5. The inside of the base is insulated with expanded clay or soil.
  6. Floor insulation.

Insulation of slab foundations.

The slab foundation has an affordable price and excellent hydro- and thermal insulation. For insulation, use polystyrene or polystyrene foam (5 - 10 cm layer)

  1. First, waterproofing is carried out.
  2. Thermal insulation boards are laid on a layer of waterproofing
  3. Polyethylene is laid with an overlap of 10-15 cm on double-sided tape.

For more information about foundation insulation, watch the video.

Insulating the base from the outside with technoplex based on extruded polystyrene foam is the best solution for saving your heating budget (increases heat by 1.5 times). In addition, you can install it yourself, since the distinctive advantage of the technoplex is its ease of use and high speed of installation work.

The high strength of polystyrene foam makes the base smooth and rigid. Thanks to the saturation with nanographite, technoplex slabs acquire a light silver tint. Technoplex type polystyrene foam is used both in industry and in private construction.

The correct selection of polystyrene foam will provide thermal insulation for many years to come. Penoplex is also considered an excellent exterior insulation of a house based on extruded polystyrene foam; you can also install it yourself (more on this in the video).

Separately, I would like to talk about the insulation of a wooden house from the outside. A wooden house is characterized by relatively easy construction, but the foundation of the house plays a very important role. What should be the foundation for building a wooden house?

Strip and slab foundations are not particularly convenient for the construction of wooden structures, firstly, they are not cheap, and secondly, they will take a lot of time.

A columnar foundation is suitable for small buildings, cottages and bathhouses. It is best to use a pile foundation; it is an ideal option for wooden houses; the foundation is both economical and reliable.

Insulating the foundation of a wooden house from the outside using polystyrene foam is the most profitable solution, since gluing the walls with polystyrene foam materials is popular and is the most common method. The foam structure retains heat and does not allow moisture to pass through from the outside (this is very important for a wooden house). Insulation can be done with your own hands.

Also, for insulating the foundation of a wooden house from the outside, insulation with foam board, penoplex and polyurethane foam is suitable.

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