Winter can be so harsh and cold and not only people freeze from the cold, but also their homes. During frosts and warming, the very structure of the surfaces that have been exposed to these phenomena deteriorates. Most often, the foundation of the house suffers. Concrete loses its properties, bursts and crumbles, which leads to cracks and deformation of the foundation of the home. And those who have a basement suffer doubly, since the floor of your house begins to freeze. This article will tell you how to insulate the foundation of a house from the outside with your own hands.
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Why insulate the foundation of a house?
Yes, everything is very simple, since condensation can accumulate in unheated basements, which in turn causes dampness, and subsequently the formation of mold, which is very harmful to health. Also, accumulated moisture deteriorates the structure of your foundation, and this is fraught with its destruction and violation of the level of the walls, which can lead to deformation of a much more serious nature. Also, in an unheated basement, all the plumbing or sewer lines of the house are often located, which, due to severe frosts, can freeze and not function properly, leading to problems with the supply and drainage of the sewer system. So it’s very worthwhile to insulate the foundation. Unfortunately, this is the most basic problem, since many people do not take this into account when building a home, hence the saying “the miser pays twice.” So it is better to think about insulating the foundation before or during construction, since after construction problems may arise with its ability to be insulated in general.
How to insulate the foundation of a house from the outside?
The choice of insulation is limited by your capabilities. Hence the quality of insulation and service life. We will look at the most affordable and effective types of foundation insulation from the outside.
Expanded polystyrene or Styrofoam- a well-known and cheapest material for thermal insulation of the foundation of a house. It differs in the density of its filling. The denser, the more expensive, but more effective. Sold in any city and on any construction market, easy to use and very affordable. The service life is about 50 years, but do not forget that this indicator depends on many factors, for example, humidity, wind and direct light rays. In the presence of such factors, the service life of expanded polystyrene (foam) is reduced several times. We also all know that polystyrene foam breaks easily and burns very strongly, thereby emitting acrid smoke.
Extruded polystyrene foam or often found with a name such as " " - the modern brother of polystyrene foam. Penoplex was created by mixing polystyrene granules with a foaming reagent (a mixture of light freons and carbon dioxide). The material is high-density, has a uniform structure with a cell thickness of only 0.1-0.2 mm. Compared to polystyrene foam, the form of sale is the same. The sheet is about 0.72 m2 and 3.5, 10, 20 cm thick. It has an excellent performance compared to classic insulating materials. For example, extruded polystyrene foam 5 cm thick is comparable to laying red hardened brick in one layer. Hence the price of this material is at least three times more than classic polystyrene foam. Likewise, the lifespan of such material has increased to 100 years, and the impact of natural factors on it is so small that it may well serve you the stated lifespan. Including “penoplex” is almost the most environmentally friendly building material in the world and has a high level of fire protection. Even if everything around is burning from the “penoplex”, not a single flame will be visible. After all, simply put, it melts, not burns.
Pouring polyurethane foam– the material, created back in 1952, has established itself as a fast type of thermal insulation. Polyurethane foam, or rather its display on the wall of your foundation, consists of several components of polyol and polycyanate, which in the reaction turn into such heat-insulating paint. By the way, the thermal insulation properties of polyurethane foam are far superior to any other insulating materials. The price of such pleasure is rightfully considered the most expensive of all known methods of thermal insulation of houses from the outside. Also, one of the advantages that applied polystyrene foam gives is: the absence of seams, covering any cracks and bends of the surface, the material is literally “prepared on the spot.” The lifespan of such insulation is very good, from 50 to 100 years, depending on the thickness of the material applied. Do not confuse polyurethane foam with polyurethane foam, as these are completely different materials for use. Polyurethane foam serves primarily as a means of sealing, but not as a means of insulating surfaces. It is almost impossible to apply poured polyurethane foam on your own, so you need the help of specially trained people.
How to insulate the foundation of a house?
Methods for insulating the foundation will depend on the material you are going to use to solve this problem. Before attaching the insulating material to the foundation, you need to apply waterproofing from the outside. Any waterproofing that does not contain acetone or solvent is suitable, so as not to disturb the structure of the polystyrene foam thermal insulation material. Water-based bitumen mastic, polymer mixtures or cement containing vapor-permeable waterproofing materials are suitable. Expanded polystyrene and extruded polystyrene boards can be attached to the foundation using special adhesives. Dry cement-based adhesive, diluted with water and applied to both surfaces, slab and foundation. Hold for a few seconds and release. To make the procedure more convincing, press it with something heavy for about 30 minutes.
Bitumen mastic is a very simple material for fastening polystyrene foam boards. Important! Bituminous mastic should not contain acetone or solvent, as this leads to deformation of polystyrene foam boards. Apply to one of the objects to be fastened, press and release. Bitumen mastic has excellent adhesive and waterproofing properties.
Adhesive based on polyurethane foam, in appearance they resemble ordinary polyurethane foam. Sold in the same cylinders and at about the same price. But the main difference from foam of such glue is the lack of expansion after application. Thus, you apply such glue using a special gun for polyurethane foam, wait a few minutes and press the polystyrene foam boards. Ta
After the work has been done, applying poured polyurethane foam or fastening polystyrene foam boards, we “mour” them under a layer of plaster with reinforcing mesh or a layer of brickwork.
In the end, I would like to remind you that in construction the main thing is to save wisely and not to the detriment of your home. Remember, " miser pays twice" And " My home is my castle» Good luck in construction and renovation!
Insulating the foundation of a house from the outside: video material.
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Foundation thermal insulation- the most important stage in building a house. It is as important as wall insulation. Especially in harsh climatic conditions characterized by freezing of the soil to great depths.
An uninsulated foundation causes serious heat loss and is dangerous due to freezing and subsequent destruction of underground structures.
Thermal insulation of the foundation from the outside significantly reduces heat loss and serves as reliable protection for the foundation of the house from the influence of groundwater and negative temperatures.
Freezing is especially dangerous for building foundation structures, on which houses are usually built.
To avoid the negative impact of the external environment on the foundation, they resort to measures such as waterproofing the foundation and its insulation.
The largest volume of cold air enters the building through the foundation. And if the house has a basement used for any functional purposes (billiard room, laundry room), then special attention should be paid to it.
An unheated basement does not need thermal insulation. But it is necessary to insulate the basement part of the foundation, especially in houses built on stilts, in order to reduce heat loss at the floor level of the residential floor. Insulation helps retain heat in the house by cutting off the path of cold air into the house.
In addition, the foundation insulation layer plays a partial role in its waterproofing.
This means the thermal insulation of the foundation:
- reduces heat loss;
- reduces costs for;
- reduces the impact of soil heaving on the foundation;
- stabilizes the temperature inside the building;
- prevents the formation of condensation on the internal planes of the walls;
- performs mechanical protection of waterproofing and foundation structures.
Which insulation is more effective?
There are two ways to insulate the foundation - insulation at the pouring stage and subsequent insulation performed after the concrete casting has hardened. The first one is the most preferable.
The most correct approach to insulating the foundation during the construction process is permanent formwork. It is a structure into which a solution is poured. At the stage of its hardening, it plays the role of ordinary formwork, but after that it is not removed, but remains as an insulation layer.
Execution technology:
- The first step is to prepare a pit from the outside of the perimeter.
- At the bottom of the pit they do: they lay geotextiles, cover it with crushed stone, on top of which they put a perforated pipe, and then again a layer of crushed stone. The pipes are tied and drained into the well.
- clean and dry, and then perform it.
- Fill the prepared trench with sand or compact it layer by layer.
Insulation with mastics
A certain amount of insulation can be achieved during waterproofing work. For example, it is recommended to cover vertical foundation walls with several layers of bitumen mastic. This insulates cracks and small holes at the joints of the slabs through which heat can escape.
After this, a roll of waterproofing material is applied to the side surfaces. It will be an additional layer of thermal insulation.
Insulation of the foundation using mineral wool
This method is used extremely rarely, because to carry it out it is necessary to build a frame, provide good protection for the mats from getting wet, and also build a protective wall from some finishing materials.
Execution technology:
- The surface is cleaned and dried, defects are eliminated.
- It is used to make a frame for mineral mats made of metal profiles.
- Thermal insulation mats are laid on the frame and secured. The surface of the insulation is protected from external moisture by a vapor-permeable wind-waterproof film.
- Protective walls or frames are erected.
Insulating the foundation with foam plastic
A modern and very effective method that qualitatively insulates foundation walls. Its advantage lies in the high thermal insulation characteristics of the material, ease of work, and the material’s resistance to mechanical damage and stress.
The disadvantage is the need for surface preparation, protection of the foam from rodents, as well as suitable waterproofing.
Execution technology:
- The foundation is dug out, cleaned and dried. Remains of bitumen, fat, and oil are removed from its surface.
- They produce.
- The slabs are laid on glue, sold in the form of a dry mixture.
- The surface of the foundation is protected from rodents with reinforcement mesh, laid on the same glue. Then the lower part of the foundation is backfilled with sand, and the upper part is secured using dowels intended for this purpose.
Insulation with polyurethane foam
This is a modern material for thermal and waterproofing both outside and inside the room. To use it, you must have special equipment that, under high pressure, sprays polyurethane foam layer by layer onto the required surface. The thickness of the polyurethane foam layer should be 5 cm. A similar insulating effect can be achieved using a layer of polystyrene foam 12 cm thick.
The advantages of polyurethane foam insulation are:
- longevity;
- high adhesive properties;
- no need for additional vapor and waterproofing.
- low vapor permeability;
- seamless coating;
- reliability;ne
- low thermal permeability;
Disadvantages include the need to use special equipment and gradual destruction from solar exposure.
Insulation with polystyrene foam
Extruded slabs almost do not absorb or allow water to pass through. Therefore, this material retains its thermal insulation characteristics for a long time.
Advantages of insulation with this material:
- long service life;
- strength;
- constancy of thermal insulation properties;
- "inedible" for rodents.
When insulating with expanded polystyrene, remember that:
- the corners of the building need “reinforced” thermal insulation,
- to insulate the soil around the perimeter of the building, a layer of expanded polystyrene should be placed under,
- The width of the blind area must correspond to the depth of soil freezing in the given climatic conditions.
- before insulating the foundation of the house, the surface of the walls must be leveled and waterproofed;
- The slabs are fixed by applying glue to them or by “melting” the waterproofing, to which the slab is then pressed and held for the time necessary for hardening.
How to insulate a shallow strip foundation
The installation of the slabs should begin from the bottom, the rows should be joined end to end. The thickness of the plates must be the same. The vertical seams of adjacent rows should be staggered.
Seams between slabs more than 0.5 cm thick must be filled with polyurethane foam.
The adhesive must be selected based on the waterproofing material. When using rolled and mastic materials based on bitumen, bitumen mastics that do not contain aggressive ingredients for polystyrene foam are used as glue.
Before insulating the foundation from the outside, be sure to wait until the bitumen waterproofing has completely dried.
Glue is applied pointwise to slabs located below the soil level, which allows condensation between the insulation and the foundation wall to flow down.
The slabs located in the ground are attached only with glue and pressed with a layer of earth.
For slabs located above ground level, it is imperative to use fastening dowels.
How to insulate a monolithic foundation slab
For the most effective thermal insulation of the floor and basement, you need to take care of the insulation of the foundation slab.
To do this, the insulation is laid on top of the waterproofing layer. Then, when using a power floor to fill, they use knitted reinforcement; in this case, it is enough to cover the heat insulator with plastic film with an overlap of 10 - 15 cm and gluing with double-sided tape.
When using a welded reinforcement structure, a protective screed from either cement-sand mortar will need to be made on top of the film, and welding work will be performed on top of this.
It should be noted that it is more correct to lay and insulate the foundation in the warm season, with a fairly high air temperature and not much humidity.
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 best 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 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. 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 order to begin work on the construction and insulation of the foundation, it is best to choose either spring-summer time or autumn, for the reason that the air is warm enough and the humidity is normal. Together with the portal, today we will talk about how to insulate the foundation of a house from the outside. In this article you will find interesting ideas for yourself and find out what materials are best used for these purposes. Below in this article we will try to tell you in more detail with the portal how it is necessary to properly insulate the foundation from the outside.
Why do you need to insulate the foundation?
The use of insulation for the foundation is the same important point in the work as the insulation of the walls in the house. Mainly where there is very cold weather and the soil freezes to a fairly large depth. The foundation of the building is capable of releasing 15-20% of heat loss into the environment. Freezing of heaving soils is very dangerous for the foundation. They can freeze in winter and increase in volume. As a result of this, the soil level rises, due to which the foundation of the building begins to deform, changing its linear dimensions. If the foundation is constructed above the freezing level, and its base is not insulated, then at the moment the soil freezes underneath it, frost heaving will occur. It will have a perpendicular direction to the top of this foundation base. Based on this, in the process of arranging the foundation, thermal insulation of its base is carried out. (or slabs).
It is worth saying that the subsequent operation of this building and the conditions for comfortable living will depend on the quality of the insulation work performed. And a plan for performing these works must be carried out during the construction of the building. Due to the fact that the main part of the cold air enters the building through the base of the foundation, during construction it is necessary to use special floor coverings, which are usually located above ground level. Basically, all the cold will be at the level of the foundation and floor, and the heat, in turn, will rise upward. And if the roof of the building was not properly insulated, warm air will be lost through it and go outside, thereby allowing the cold to penetrate inside the building. But if your basement is intended for functional purposes, then it should be insulated as well as possible. Perhaps a gym will be located in this room, or a laundry room; in any case, the room should be cozy and comfortable. But if you do not properly insulate the foundation, then you will be provided with increased humidity and dampness.
A basement that is not equipped with a heating system, as a rule, does not require thermal insulation. But here it will be necessary to start insulating the basement part of the foundation in order to reduce heat loss along the floor level on the 1st floor of the heated room. Carrying out work on thermal insulation of the foundation base will help you save maximum heat in the building and close the path of cold. You must always remember that with excellent insulation of the house, as well as its foundation, you can save approximately 35-45% of your money intended for heating. In addition to thermal insulation, the main insulating layer of the foundation will play an important role in waterproofing. Now let's try to find out what the main role of foundation insulation is.
- Reduces heat loss;
- Makes it possible to reduce heating costs;
- Almost completely reduces the impact of frost heaving forces on the foundation;
- Balances the temperature inside the building;
- Prevents condensation from forming on the inside of the walls;
- Performs the function of protecting waterproofing;
- Serves as a factor in the longevity of the entire foundation of the building and waterproofing.
What insulation should you choose for the foundation?
In this article we are talking about how to insulate the foundation of a house from the outside. Here we will provide our readers with useful tips and invite you to watch an interesting video. Carrying out thermal insulation work first of all includes the correct choice of insulation.
What material is needed to insulate the foundation of a building?
First of all, it must have the following characteristics:
- do not absorb moisture into its base;
- do not change their linear dimensions and do not deform under the influence of soil pressure.
Currently, in the construction markets you can see a huge number of different thermal insulation materials. It is clear that mineral wool in this case is not suitable for insulation due to its very soft and water-absorbing properties, since this reduces the thermal insulation qualities. In order to insulate the foundation, many experts advise remembering 2 main methods:
- Insulation using extruded polystyrene foam;
- Carrying out work on spraying polyurethane foam.
These materials differ from each other in terms of their thermal insulation parameters and price. To make a more competent choice of this product, you should first study in detail all its advantages and disadvantages. Polyurethane foam is one of the popular insulation materials, which carries several main functions at once - it provides maximum hydro-, heat and sound insulation. In order to use it in work, you will need certain equipment, with the help of which polyurethane foam will be sprayed layer-by-layer onto the insulated surface. The thickness of its layer should be 50 mm, with a material density of 36 kg/m3. The same effect can be achieved by using polystyrene foam with a thickness of at least 120 mm.
Polyurethane foam
In a coating such as polyurethane foam, all seams and gaps are usually absent. When carrying out foam insulation work, all existing joints should be hermetically sealed. This will also require special mounting fasteners, which, in turn, will increase the cost of the work performed and increase time. The main advantages of using polyurethane foam:
- High adhesion of this material;
- Seamless coating;
- Strength;
- Little steam and heat permeability;
- Longevity of the material.
- There is no need to carry out additional work on steam and waterproofing.
The main disadvantages of this material include the mandatory presence of certain equipment and the harmful effects of ultraviolet radiation on it.
Insulation of the foundation with polyurethane foam
The only advantage of extruded polystyrene foam is its low price. But this fact does not make it more significant, for the simple reason that installation work is quite difficult and this material, in addition, has very low thermal insulation functions. Plates consisting of extruded polystyrene foam do not absorb moisture, as they have a closed cellular structure. This suggests that this material is not subject to destruction over time and freezing will not occur. For this reason, extruded polystyrene foam has a maximum service life while maintaining its thermal insulation properties.
It should be noted! What is the answer to the question “What is needed to insulate the foundation? we offer this... The use of standard foam plastic for thermal insulation of the foundation, as a rule, can lead to the fact that after a large number of seasonal cycles of freezing and warming up the foundation base, the layers of this material undergo crumbling. This factor occurs due to the fact that polystyrene foam absorbs all moisture very well. And to carry out vertical insulation of the foundation of various industrial or civil facilities, it is done using extruded polystyrene foam slabs having a compressive strength of 250 kPa or more. When insulating private buildings, polystyrene foam with a compressive strength of 200 kPa is used. To insulate floors, slabs with a strength of 500 kPa should be used. These strength features of this material are very capable of maintaining the integrity of the waterproofing part of the foundation. Also, thanks to extruded polystyrene, a long life of the foundation itself is ensured. Among the wide variety of insulation materials, as well as extruded polystyrene foam, there are slabs with special milled grooves. Together with geotextile fabric, this type of insulation perfectly performs the role of drainage, protects the waterproofing layer of the foundation as much as possible and removes the moisture accumulated in it into the drainage system.
Pay attention to the publication of the portal: Tips on how to choose polyurethane foam
Thermal insulating polystyrene boards with milled grooves
The main advantages of extruded polystyrene foam:
- Long service life (more than 35 years).
- Increased compressive strength.
- During use, constant hydro- and thermal insulation characteristics are achieved.
- This material is not edible for rodents.
Insulation of the foundation using expanded clay
More recently, a material such as expanded clay was considered the most popular for the ability to insulate the foundation from its outer part. But it was supplanted by those methods of foundation insulation described in our article above, which, in turn, are cheaper and better in their properties.
How to insulate the foundation of a house with polystyrene foam from the outside
There is a basic rule for insulating the outer part of the foundation. It occurs, as a rule, in areas of soil freezing by installing special heat-insulating slabs at the required freezing depth. And the corner sections of the foundation, in turn, should be insulated as much as possible. To do this, the layer of polyurethane foam or slab in the corners of the foundation is increased by one and a half times. You should also insulate the soil itself around the entire perimeter of the house. A layer of insulation consisting of extruded polystyrene foam should be located under the blind area. It is used mainly to reduce the depth of soil freezing around the walls, as well as to maintain the freezing boundaries in a layer of non-heaving soil running along the walls of the building.
When laying slabs of extruded polystyrene foam, the angle must be at least 2%. The width of the blind area itself should be equal to the depth of soil freezing in a given climatic zone. The most ideal thickness of the slabs should correspond to the thickness of the vertical insulating layer of the foundation.
How to insulate a foundation with penoplex
In this article, we not only talk about those materials that are suitable for insulating a foundation, but also tell you how to insulate a foundation from the outside with various materials that are suitable for such a task.
Before you begin to insulate the outer part of the building’s foundation, you should prepare the surface of the walls by leveling them and waterproofing them.
Foundation waterproofing
When installed, extruded polystyrene foam slabs act as a durable and airtight shell for the outer part of the foundation. For this reason, the use of special fasteners to be able to fix this material cannot take place in this case, since depressurization of the insulating layer may occur. The work of fixing these slabs is carried out by applying glue to their outer part or by melting a layer of special bitumen waterproofing at 4 or 6 points. Next, polystyrene foam is pressed tightly against them.
How to insulate a strip foundation
The installation of thermal insulation boards should be done from below, and the rows, in turn, are connected to each other end-to-end. The thickness of these plates should be the same. Seams located next to each other should be combined with each other using the checkerboard method. All seams formed between the insulation boards are usually filled with polyurethane foam.
It is quite convenient to insulate with slabs that have a stepped edge. If it is completely glued, a dense and airtight layer will be created, as well as additional insulation of the foundation itself. Depending on the waterproofing material used, the adhesive is selected. When using bitumen-based mastic or roll materials for waterproofing, bitumen mastic is used as an adhesive solution, which, in turn, does not contain aggressive components for expanded polystyrene.
Before insulating the outer part of the foundation, you should wait until the bitumen mixture has completely hardened (about 6-7 days). Under no circumstances should expanded polystyrene slabs be installed on a wet bitumen mixture, as they will corrode and all waterproofing will be damaged. On the same slabs that will be mounted below ground level, glue is applied in the form of several small dots. This method will ensure that the accumulated moisture in the space between the wall and the insulation can drain down. The use of special fasteners together with an adhesive solution consisting of polymer-cement adhesives is necessary for installing slabs that are located above ground level in quantity - at least 4 pieces per 1 slab. Those slabs that are located in the ground itself are mounted using an adhesive composition and pressed against the soil layer.
How to insulate a foundation slab
From this article we learned how to insulate the foundation of a house from the outside with our own hands. When drawing up a plan for how to insulate the foundation from the facade in order to effectively insulate the basement and floor, you need to think about the possibility of insulating the base of the foundation (slab) itself. In this case, insulation boards are mounted on a waterproofing layer. If knitted steel reinforcement is used to fill the reinforced floor, then the top thermal insulation layer can simply be covered with PVC film with a slight overlap of 100 or 140 mm and taped. If welded reinforcement is used in this work, then a concrete screed will need to be made on top of the film, and only then welding work will begin.
In wooden houses, less effort and money is spent on insulating all structures than in other types of buildings, because wood has low thermal conductivity. But even in log houses there are elements that cannot be made of wood, and often they become conductors of cold entering the house. The greatest heat loss awaits the owner who did not provide for insulation of the foundation, which is in direct contact with the ground. And since most often the foundation is mounted from concrete slabs or a monolith with high thermal conductivity, the percentage of heat leakage through the base can reach 20%. Let's consider how to insulate the foundation and what materials should be used.
Video advice from a specialist on thermal insulation of a wooden house
When is it better to insulate the foundation of a wooden house?
The most optimal time for insulating the foundation is the beginning of construction, when the walls are not yet standing and the subfloors have not yet been laid. But, unfortunately, most often the problem begins to brew during the operation of the building. And the first signals are dampness and mold in the underground, damp basements, which in winter are covered with frost and frost on the side adjacent to the street. But even in this case, it is not too late to insulate the foundation of the house.
It is most convenient to insulate the foundation before erecting the box
Isolation of the foundation box from direct contact with the soil
When the foundation is built, there is a lot of empty space inside the foundation box. If you are not planning a basement (or placing it under part of the building), then the entire box should be covered with earth or expanded clay to the level of the future floor. It will become an additional layer between the soil and the floors. The land will be cheaper, especially since when digging a pit a lot of excess soil is formed, which the owner has to fill inside the foundation. True, this method is simple only at first glance. If you have to use imported soil, then for an embankment one meter high for a 10x10 box, the land consumption will be the volume of seven KAMAZ trucks. In addition, it is unlikely that the equipment will be able to pour the brought soil inside, and you will have to shovel the entire volume manually. And the main disadvantage of earth insulation is the poor quality of thermal insulation.
It is more profitable to backfill with expanded clay. They do not fill the entire box with it, but only 40 cm from the inner walls of the foundation. In this case, you will save the basement, and you can place communication junctions underground.
To create expanded clay insulation, it is necessary to install formwork along the inner perimeter of the walls. It will not be removable, so use any durable materials that, due to their external characteristics, will not be used outside the building. Slate, cutting boards, etc. are suitable. Expanded clay is poured inside the finished formwork, and when creating a subfloor, it is covered with a waterproofing layer and mineral wool.
If the laid communications do not allow you to pour expanded clay inside the box, then you can insulate it from the outside by adding waterproofing protection in the form of a brick wall
This method of insulation better insulates the house from the cold than earth, but it should be used as an addition to the main work. The main condition for good thermal insulation of the foundation should be the protection of its walls from cold and moisture. It is performed by gluing or spraying insulation materials onto the outer walls.
How to install foundation insulation from the outside using polystyrene foam
The most common way to insulate a foundation from the outside is to cover the walls with polystyrene foam materials. Due to the foamed structure, polystyrene retains heat well and, importantly, practically does not allow moisture to pass through. Cheaper is ordinary polystyrene foam, which is popularly called polystyrene foam. Extruded polystyrene foam, otherwise called penoplex, is more expensive due to the peculiarities of production and individual additives.
Polystyrenes are produced in the form of slabs of different thicknesses. Choose the right size taking into account the future use of the basement and the characteristics of the local climate. Most often, in Russian conditions, 5-centimeter slabs are installed, but if the basement is equipped for a wine cellar, where the temperature should be about 10 degrees, then 10-centimeter insulation is used. Particular attention is paid to gluing the corners, because this is where the freezing of the foundation begins. To do this, take slabs 3-4 cm thicker than the main insulation.
Foundation thermal insulation technology using extruded polystyrene foam
External foundation insulation with foam plastic
During production, the foam acquires a light structure, saturated with air bubbles, due to which it retains heat well. The same property made polystyrene foam moisture-permeable and ventilated. But the cells do not fit too tightly to each other, so during installation the material may crumble or break.
This insulation works great on soils with low levels of freezing, provided that it is protected from moisture on both sides.
External insulation of the foundation with penoplex
If you carry out insulation of the foundation yourself in an area where winters are harsh and the soil freezes to great depths, then it is better to use penoplex. It is three times more durable than foam plastic, so it will withstand the pressure of frozen soil and will not crumble. In addition, extruded polystyrene foam has a more elastic, closed-porous structure that does not allow moisture to pass through.
What is the difference between waterproofing and foundation insulation with polystyrene foam and penoplex?
If you insulate the foundation of a wooden house from the outside using penoplex, then you will not need to cover it with waterproofing material. All other stages of installation of polystyrene insulation are carried out according to the same scheme, as you can see by watching the video - how to insulate the foundation from the outside.
- Soil preparation
A trench is dug along the entire perimeter of the foundation to the depth of the foundation. If the level of freezing in your area is low, then it is enough to dig just below the maximum limit. Since polystyrene is placed on a rigid base, it is worth covering the trench with a layer of sand and gravel (10 cm) from below and compacting them.
The deeper the trench is dug, the higher the thermal insulation of the foundation slabs will be.
- Foundation preparation
Before insulating the foundation, clear it of any remaining soil and level out any uneven areas with cement mortar. For high-quality thermal insulation with polystyrene, a flat surface is needed to ensure maximum adherence of the insulation to the wall. The finished base must be primed.
- Foundation waterproofing
The next stage of work is waterproofing the foundation. Why is it needed? There are no absolutely vapor-tight insulation materials, so some moisture will still seep into the insulation and penetrate into the concrete base. Moisture is not a problem for polystyrene, but concrete can crack in the cold. Therefore, it is necessary to coat the entire outer surface of the foundation slabs with liquid rubber or glue them with bituminous materials. It is easier to do this with a rubber compound, since it is sold ready-made. All that remains is to carefully move and go over the entire foundation with a spatula.
Rolled bitumen materials require the ability to operate a torch. Moreover, all joints must be heated very carefully so that there are no seams left through which moisture can pass into the thickness of the foundation.
You can also use bitumen-based mastics.
- Pasting insulation boards
To fix polystyrene foam to the foundation, polyurethane glue or mastic based on bitumen and polymers is used. Be sure to read the ingredients in advance to ensure there are no organic solvents. If you find acetone, gasoline, etc. among the components, then such compositions will not be suitable for pasting. They destroy the polymer structure of the insulation and lead to ruptures of the slabs. Lubricate the polystyrene foam either spotwise or by brushing the base itself. Laying begins from the bottom of the corner, placing the slabs on a sand bed. Having laid the first row, they begin the second so that its seams fall in the middle of the underlying sheets, like brickwork. The slabs are connected with grooves into a lock, but if you have to trim the edge, then the joint must be lubricated with mastic or glue. When joining corners, it is recommended to seal the seam with foam to close any possible cold bridge.
- Laying outer protection
The last stage in installation is to isolate the insulation from external factors. The underground part can be covered with roofing felt and sprinkled with soil if you use penoplex. When laying polystyrene foam, additional waterproofing will be required. A waterproof film is pasted over the roofing felt or a brick wall (half a brick) is placed. The outer part is reinforced with fiberglass mesh, plastered and covered with finishing material.
Protective brickwork will protect the foam from moisture coming from the soil
External foundation insulation with polyurethane foam
Some owners are looking for how to insulate the foundation of a wooden house as quickly as possible. To do this, it is worth using sprayed polyurethane foam insulation. Workers will mix the components right at the construction site and apply the liquid composition to the entire outer surface of the foundation within a day. After hardening, polyurethane forms a dense, continuous, seamless coating with characteristics similar to penoplex. True, in this case the cost of insulation will be high.
When choosing between external and internal insulation, give preference to the first option, since it is possible to insulate the foundation of a house from the inside only if there is high-quality ventilation in the basement. Experts believe that internal insulation shifts the dew point, as a result of which the foundation is completely under the influence of external moisture and cold and quickly begins to collapse. Insulation creates increased humidity in the basement, and only additional ventilation can eliminate it. And these are unnecessary expenses. In addition, part of your usable space will go under the “pie”.
Due to the absence of seams, sprayed polyurethane provides high thermal insulation
But if there is no other way out, then it is best to use liquid polyurethane foam, which provides maximum protection from moisture.
Without insulation of the foundation, the first floor will always suffer from dampness in the corners and cold.