How to glue foam to concrete on a wall

How to glue foam plastic to concrete - 4 types of adhesives

Often in construction processes the question arises of how to glue foam plastic to concrete. Modern industry offers the consumer a large number of fastening materials that will help adapt polystyrene foam to the concrete surface and strengthen the thermal insulation elements efficiently and reliably.

Attachment methods: list of adhesives
Construction adhesive: a budget option
Liquid nails: reliable installation
Fastening with polyurethane foam
Efficient fastening method
Preparation: stages of proposed work

Preparation: stages of proposed work

The initial stage before gluing the foam is preparing the surface. Therefore, preparatory work is carried out, which consists of the following stages:

Immediately before gluing the foam to the concrete, it is recommended to ensure that the surface is dry, since the material is not resistant to a humid environment. After the concrete wall or ceiling has completely dried from protective agents, the process of installing polystyrene slabs begins. The nuances and rules of installation directly depend on the type of adhesive chosen. Detailed instructions for use are clearly written on the label of the intended material.

Source

Methods of fastening polystyrene foam

Modern developments offer a wide range of construction adhesive materials that facilitate gluing or fastening materials of absolutely any nature.

If you are wondering how to glue foam to concrete, then you have the opportunity to choose one of the following options:

Dry adhesive mixtures.
Polyurethane foam.
Liquid Nails.
Use of mechanical fastenings such as dowels.

The choice of method for installing polystyrene foam boards on concrete surfaces depends on financial capabilities, installation location (outside or indoors) and the degree of unevenness of the working surface.

A few important tips before starting installation

Preliminary preparation of the concrete base includes the following steps:

clean the surface of any contamination;
embroider and plaster large defects in the base;
prime the entire surface.

Completing each pre-installation step is important to create optimal adhesion, regardless of the method of fixing the polystyrene.

Choosing a method for fixing expanded polystyrene sheets to concrete involves analyzing the condition of the surface. The methods also differ in the speed of work and the amount of required costs.

Methods for attaching foam to concrete

Using dry mixes

Dry building mixtures are considered a practical choice when installing polystyrene foam on the facade of a building, or on a large surface area indoors.
For exterior work, cement-based compositions are used, and for interior work, gypsum-based compositions are used. The mixtures are supplied in paper bags; to prepare the solution, the powder is diluted with water in the proportions specified in the instructions. Advantages of gluing foam plastic using dry mixtures:

durability and strength of adhesion to the base;
moisture resistance and frost resistance;
low cost;
the ability to adjust the position of the sheet within 20 minutes after applying the adhesive;
correction of small irregularities using an adhesive mixture.

Disadvantages of using dry mixes:

impossibility of installation at temperatures below 0 C;
the finished glue must be used within two hours;
the possibility of errors in proportions when mixing the adhesive mixture;
the composition completely hardens within three days;
Additional tools are required (mixing container, drill with attachment, spatula for application).

Expanded polystyrene is not a hygroscopic material, so you need to make sure that the dry mixture is completely mixed and homogeneous. The appearance of free water in the mixture can cause the polystyrene board to soon move away from the surface.

Depending on the quality of the base, you can use one of the methods of applying the adhesive mixture:

Solid . Suitable for the most flat surface possible, differences of no more than 3 mm are allowed. The adhesive is applied in an even layer over the entire insulation sheet using a notched trowel, and then applied to the concrete base.
Cavitary . Acceptable for bases with differences of no more than 5 mm. The glue is applied in a thin strip along the perimeter of the sheet, retreating from the edge about two centimeters. Then it is also distributed over the center of the foam. This method will eliminate air pockets under the insulation.
Mayachkovy . Use for uneven bases up to 15 mm. The glue is applied in intermittent strips around the perimeter of the sheet, leaving a gap of two centimeters. The height of the strip should also be two centimeters. The same “beacons” are placed in the center of the sheet.

The foam is firmly pressed to the surface and held in the desired position for some time to ensure fixation. Excess glue protruding along the edges is removed with a damp cloth.

Bonding with liquid nails

“Liquid nails” are a paste-like mixture of polymers with various additives.
They are sold in oblong tubes; to work with the substance you will need a construction “gun” for sealants. High-quality “liquid nails” are able to set even in high humidity. There is a large selection of adhesive compositions on the market for different applications, so before purchasing you should read the instructions and use only “liquid nails” for gluing polystyrene foam. Gluing polystyrene insulation to a concrete base using “liquid nails” requires a flat, prepared surface; the use of this product is effective when working in small areas.

Advantages of gluing with liquid nails:

strong grip;
quick installation;
heat resistance and frost resistance;
setting time - from 10 to 30 minutes;
the ability to smooth out small irregularities;
low consumption;
no smell.

Disadvantages of using “liquid nails”:

rapid setting does not allow adjustment of the position of the insulation sheet;
the composition contains toxic substances, so you need to wear protective gloves;
high cost of material when working over a large area.

Installing foam plastic on a concrete base does not require applying “nails” to the entire surface of the sheet. The polystyrene plate is covered with the composition in spots or in intermittent stripes around the perimeter. Then the sheet is pressed against the surface with force and held in this position until it sets. The seams between polystyrene sheets are treated with polyurethane foam or sealant.

Bonding with foam

Polyurethane adhesive foam is a special construction adhesive composition, which is a one-component polyurethane aerosol in cylinders similar to conventional polyurethane foam. To work, you will need a special gun, with which the composition will be released from the cylinder.

When purchasing assembly adhesive, it is recommended to immediately purchase a special cleaner - remover. This composition will be needed to wash the gun and remove excess foam during operation.

Polystyrene foam can even be glued to regular polyurethane foam. However, when it dries, it increases significantly in volume, which can lead to deformation or breakage of the insulation sheet, as well as divergence of the seams. The work time will also increase, since you will have to press the polystyrene slabs to the surface for a long time. It is worth using a special adhesive foam for polystyrene foam.

Advantages of gluing expanded polystyrene onto foam:

high quality grip;
ease of use and quick work;
fire resistance;
no odor;
a moisture-resistant and frost-resistant compound is formed;
possibility of carrying out work at sub-zero temperatures;
dowels can be installed a couple of hours after gluing the sheets;
shrinkage and expansion of the adhesive are excluded.

Limitations of using foam for gluing polystyrene:

installation should be carried out quickly, without interruptions, since the composition may harden in the gun;
the most flat surface is required;
instability of foam to ultraviolet radiation;
high price of material.

Assembly adhesive is applied in strips along the perimeter of the foam sheet, indenting a couple of centimeters from the edge. In the center of the sheet the composition is applied in a zigzag or cross pattern. The joints between the plates are also filled with foam, and the excess is removed with a cleaner.

Consumption per 1m²

The amount of consumption of adhesive compositions depends on the method of application. Adhesive foam is distributed pointwise. This will also save material.

The consumption of foam adhesive from 1 cylinder is for 10-12 m² of concrete base. Depends on the brand of product and method of use.

Video: how many sheets of polystyrene foam can be glued to adhesive foam.

Powdered substances are sold in 25 kg bags. Shelf life 6 months. They differ in properties and consumption. Dry materials for gluing thermal insulation are used at a rate of 6 kg/m². The minimum amount that can be applied is 3 kg/m². Application depending on brand:

“Ceresite” will need 6 kg/m²;
“Knauf” - 4 kg/m²;
"Titan" - 6 kg/m².

Consumption will be less if applied in a thin layer. Using a notched trowel will also help save material.

Dry mixtures: preparation and features of use

Technical characteristics of the adhesive mixture Ceresit CT 83.

Cement-polymer mixtures can be used to glue foam to brick, plasterboard and concrete surfaces. The mixtures contain Portland cement, a plasticizer and additives that enhance their properties. AQUALIT SK-106P glue is especially resistant to cold and moisture. A special feature of using ANSERGLOB BCX 39 adhesive is the need for deep priming. ECOMIX BS 106 glue is used for interior work. The dry mixture “MASTER SUPER” is suitable not only for gluing expanded polystyrene, but also for covering the slabs with a reinforcing layer on the outside.

Under the CERESIT brand, a whole range of dry mixtures are produced: both universal and specialized. The ST-85 adhesive is universal. It contains a large number of polymers, which makes the mixture very durable and increases its ductility. However, expensive additives significantly affect the cost of the glue. If you need to glue foam plastic, it is better to use dry glue ST-83, which will cost about one and a half times less. When preparing the mixture, keep in mind that it will harden within 2 hours, so you should not mix it in large portions.

Using a product prepared from dry cement-polymer mixtures, you can glue foam plastic to concrete, even if it has an uneven surface. In this case, the glue must be applied to the plate of material in intermittent strips, retreating 2 cm from the edge of the sheet. Then the air from under the slab pressed to the surface will come out unhindered and will not form air pockets under it. For small unevenness, up to 3 mm, the mixture can be spread with a notched trowel.

Before gluing the polystyrene foam, you need to make sure that there is no water in the self-prepared mixture. To do this, the product must be thoroughly mixed until it becomes homogeneous, without lumps.

Using a drill with a special attachment will make the process much easier. You just need to make sure that the nozzle is completely immersed in the solution, otherwise air bubbles will form in it. The mixture should then sit for about 5 hours, after which it is stirred again and used immediately. If the glue is not cured for the time specified in the instructions, the presence of water in it will interfere with quality adhesion. After all, foam plastic practically does not absorb moisture, and glued slabs of material will not allow it to dry out.

Recommendations for work

Before gluing foam plastic to concrete, regardless of the type of fixing composition, the base is prepared in the same way. Cleanliness, strength, absence of rust, oil stains, fungal formations are the main conditions. Regarding evenness, differences can be partially compensated in accordance with the maximum layer of the selected adhesive.

It is necessary to select adhesive compositions taking into account operating conditions. Even under layers of plaster and finishing to insulate the facade, you need to use materials suitable for outdoor work. Universal options for deciding how to glue foam to metal or other surfaces should be left on the counters. They last less time and are inferior in quality to specialized samples. And the thermal insulation finish lasts for a long time.

It is important to carry out installation work so that no glue gets on the edges. Any voids will subsequently allow cold air flow through. It is better to additionally fill the joints with foam or sealant after laying the thermal insulation sheet.

To avoid cold bridges, there are 2 more rules for gluing polystyrene foam to concrete. Factory slabs are made of geometrically correct rectangular shapes, often rectangular. That is, maintaining the level will allow you to create the most even seams. Each subsequent row is shifted to the side in relation to the previous one. At the intersection of 4 corners, air penetrates better than with a staggered arrangement of plates.

This video demonstrates an experiment on what is more effective – foam or an adhesive mixture for gluing foam plastic:

Reply to reader

We welcome you, Peter, to the vastness of our website! You are right, indeed, the foam will corrode if you use acetone-based compounds, so do not use them under any circumstances. Now we will name the 3 most common ways to solve the problem assigned to you. But first…

Preparing the concrete surface

Regardless of what type of glue you use, the surface must be properly prepared to obtain a reliable connection.

The procedure will not take much of your time, but it must be done.

First of all, take a hard spatula and go over the entire surface of the ceiling, removing small debris and possible growths from it. If there are frozen pieces of concrete, you may need the help of a hammer drill. All protruding metal parts are cut off with a grinder.
Mark the ceiling with a brush and prime it thoroughly - preferably in two layers.
After the primer has dried, seal the seams between the concrete slabs with gypsum or cement plaster. An option with polyurethane foam is possible, the main thing is to ensure insulation from drafts and prevent large unevenness (excess foam is cut off with a sharp knife).
Separately apply primer to the dried plaster.

All! The ceiling is ready for further work.

Dry mixes

The first way we will consider how to glue polystyrene foam to concrete is to use a dry cement-based mixture.

These adhesives contain special polymers that provide reliable adhesion between these materials. Before use, the mixture is diluted with water in the proportions indicated by the instructions for use on the label.

What is so special about this method?

Cement adhesive has a long service life;
Concrete and foam grip quite reliably;
The hardened composition will be resistant to temperature changes and possible humidity in the room;
During installation, you can adjust the position of the foam boards within a few minutes, which is very convenient;
The price of such a solution will be low, and therefore beneficial for the consumer.

The disadvantages are insignificant, but they are worth knowing.

Do not perform work at sub-zero temperatures;
You need to carefully monitor the consistency of the glue - the ease of application and the quality of the adhesion depend on it.
Complete drying will occur only after three days.

A similar method is used, mainly if the ceiling has some unevenness, and depending on their size, three methods of applying the adhesive mixture are used:

If the differences do not exceed 3 mm, then a continuous application method is suitable. It involves spreading the mixture using a spatula-comb. Having received a uniform layer over the entire surface of the foam slab, we lift it to the ceiling and press it tightly. The force should be enough to squeeze out the glue a little, but be careful not to push through the foam itself. Press evenly over the entire surface of the slab
The second method, cavity, is used if the concrete surface has unevenness from 3 to 5 mm. The glue is applied in strips, retreating 1.5-2 centimeters from the edges - first along the perimeter, leaving small gaps, and then inside. The gaps are needed to ensure that there is no air pocket under the foam.
The latter method is called beacon method and is used if differences reach 15 millimeters. The glue is applied in strips 5 centimeters wide and 2 centimeters high. There should also be gaps.

Protective covering

Scheme for attaching penoplex to a brick or concrete wall
In order for the surface of the insulation to look beautiful and be durable, it must be protected. The simplest and cheapest way to protect insulation is plastering, which is carried out in stages.

Selection of plaster mortar.
Read also: 11 ways to secure plastic windows on the 1st floor from opening

Selection of reinforcing mesh for plaster mortar.

Fastening the reinforcing mesh using a certain technology.

Laying the mortar, leveling the surface, grouting with a plastic float.

Primer the surface for the finishing coat.

Finish plaster. After drying, painting is done or a transparent protective layer is applied.

Video instruction:

In general, attaching penoplex to concrete and brick walls, as well as insulating the foundation of a building, is not difficult. It is enough to follow the installation technology and carry out the work carefully to ensure that the insulation is attractive and durable.

How to glue foam to the wall?

As mentioned earlier, the building materials market has a huge variety of different dry mix adhesives and other chemicals, which will allow the modern consumer to choose the best option for fastening and gluing a variety of materials. So, let's answer the question: how to glue foam to concrete?

To glue polystyrene foam to concrete, you must use one of the following methods:

Fastening with liquid nails.
Fastening using foam adhesive.
Of course, using a dry adhesive mixture for polystyrene foam.

Now let's briefly look at each of these methods separately and in more detail.

Floor insulation

Floor in the bathhouse. Insulation is carried out on a flat surface

Penoplex is excellent for insulating floors in a wooden house. Due to the fact that it almost does not absorb moisture, it can be used effectively in a bathhouse. This can be done even without a screed. If installed in a steam room, it is necessary to ensure that the thermal insulation is not adjacent to the stove or other heating elements.

Sheathing a balcony from the inside, especially if it is on the upper floors, is easier to do by gluing Penoplex slabs to its inside. Next, you can hide the slabs using lining, plastic or MDF. Penoplex is an excellent thermal insulation material. Due to its lightness, it is convenient to install on any structure, especially since there are many installation methods. To the question: is Penoplex harmful to health, you can safely give a negative answer.

Gluing foam plastic with liquid nails

Materials and tools:

Liquid nails are applied pointwise to foam plastic, but at the same time they provide a reliable connection.

expanded polystyrene boards;
liquid Nails;
protective gloves.

Gluing expanded polystyrene to concrete using liquid nails is a much more durable method than using glue.

Liquid nails are a heat-resistant and moisture-resistant material that hardens even in high humidity.

Liquid nails do not need to be applied to the entire surface of the slab; only a few points need to be made. Before starting work, you should study the instructions for using liquid nails. A certain type of glue is suitable for a particular material, for example, concrete. Liquid nails contain toxic substances, so you must wear protective gloves when performing the work.

If polystyrene foam is glued to the ceiling, then the curing time of the glue must be taken into account. A certain brand of glue has a characteristic setting time. Usually it is about half an hour. After applying the glue, you will need to press the slab against the ceiling for 30 minutes. Before starting work, the surface of the ceiling or wall is cleaned of dirt and dried. After this, several points of liquid nails are applied to the foam sheet. Glue the sheet to the surface, pressing for a while.

Additional recommendations

Expanded polystyrene is not hygroscopic, so free water should not be a component of the adhesive, otherwise the boards will separate from the load-bearing surface. You should also prevent their contact with adhesives containing solvents (gasoline, acetone), which destroy the structure of the material. The purpose of adhesive compositions and the conditions for their use should be determined from the manufacturer’s recommendations on the packaging.

Work begins with ensuring high adhesion of concrete surfaces (cleaning from dust, building materials, greasy stains, priming) with an adhesive applied to the insulation boards. Before they begin, deep defects and cracks are widened and sealed with sand-cement mortar, then the surface is primed again.

Expanded polystyrene sheets are glued from the bottom up from the level line. Adhesive compositions are applied in such a way as to avoid the formation of air plugs under the surface of the sheets. The joints between the plates are not specially glued, since they are subsequently filled with sealant.

In some cases (due to the long setting time of the mixtures), it is necessary to forcibly hold the slabs pressed with their entire plane to the concrete surface until the mixture sets. All thermal protection after the glue, foam or liquid nails have hardened can be additionally secured with dowels. Their number on a sheet can be more than five (center and 4 corners) if it has a significant area.

How to glue foam to concrete

Polystyrene foam is an almost irreplaceable material for insulating building facades, walls and ceilings inside rooms, balconies and basements.
It is environmentally friendly, practical and safe to operate, while at the same time having a low cost. Working with the material does not present any difficulties, since the weight of the slabs is quite small, which makes them easy to cut and glue. Polystyrene foam has the ability to retain heat well. The effectiveness of thermal insulation can be increased by ensuring the tightest possible contact of the material with the working surface. Installation of slabs must be carried out strictly according to technology. The choice of glue is also very important: first of all, it must be of high quality.

Only after this will it be possible to decide how to glue the foam to the concrete, and which of the 2 types presented by the manufacturers is better: polyurethane adhesive foam or dry-mix adhesive.

Adhesive options

Among the specialized compounds, you need to choose the right way to glue polystyrene foam to concrete, metal or wood. They differ in chemically active substances that are responsible for the degree of adhesion to the base. Below we will look at the features of possible solutions.

Dry mixes

Powdered materials, as a rule, are inexpensive and can be stored longer after opening the original packaging. Working with mixtures is easy. You just need to add water according to the recipe and mix everything until smooth. Some manufacturers recommend leaving the solution for 3-5 minutes and stirring again.

Before gluing foam to concrete on the ceiling and walls, they need to be properly prepared. Strength and integrity, cleanliness, absence of dust, rust and fungal formations are important here. Glue peeling also occurs due to oily stains. That is, we remove everything, repair it, fix it, clean it and treat it with a primer.

High-density polystyrene foam has a smooth surface. In order for the glue to adhere better to it, it is worth scratching the sheets a little with a brush with metal bristles. Then, of course, you need to remove the dusty excess.

Polyurethane foam

This group of building materials is of a polymeric nature, so it can also be a solution to gluing foam plastic to concrete. Only winter samples are unacceptable, as they contain destructive toluene. There is no need to mix or dilute anything here. There are cylinders for working with a separate gun or with a tube that comes with the kit. Before use, you only need to shake the contents for a minute.

The rationality of using foam for gluing foam plastic comes down to the simplicity and speed of installation work. But this approach is relevant if the work site is pre-leveled. And also for large objects it is better to choose less expensive dry mixes.

You need to choose compositions with polymer components that are compatible with polystyrene foam. A water-soluble mass will not work, since water does not penetrate into the foam. That is, such liquid nails may not adhere to the insulation.

Calculation of the required amount of materials

Any work related to repair and construction begins with the calculation of the required amount of material. To do this, it is enough to know the area of the surface to be covered. To insulate residential premises, foam plastic of various thicknesses is used, but the ideal material would be one whose thickness is more than 5 cm, and its density ranges from PSBS-15 to PSBS-35.

To fix the boards, you can use dowels, foam glue or regular cement-based glue. When choosing an adhesive, consider the following points:

there should be a mark on the package that the adhesive is suitable for fastening polystyrene foam boards;
the purpose of the glue can be installation of insulation and filling cracks or with the possibility of installing a protective layer.

Calculation of glue should be carried out taking into account the evenness of the surface. The average amount required to install insulation with your own hands is about 5 g/m2. Approximately the same amount will be required for attaching the reinforcing mesh and leveling layer.

There are general rules for preparing the solution:

The thickness of the adhesive should be such that the solution does not change its shape when applied. That's why sometimes you should deviate a little from the manufacturer's recommendations;
to attach the reinforcing mesh, the glue should be a little thinner. This is required for better deepening;
The solution should be even more liquid when using it at the final stage, for installing the leveling layer.

Preparatory activities

Insulation allows you to save on heating the room. You can attach the foam to the wall after preliminary preparation of the surface.

The process consists of performing a series of actions to level and strengthen the base. It all boils down to this:

unnecessary structural elements are removed from the working surface;
falling sections of the finishing coating are removed to a solid base, after which they are plastered again;
walls are checked for unevenness by level;
if necessary, the entire surface is leveled and puttied;
after drying, wash off the dust formed on the installation surface with water (can be wiped with a damp cloth);
when the moisture has evaporated, apply sequentially: a primer layer, a solution against mold and fungi (with a brush or spray);
Before attaching polystyrene foam, you should take measurements of the wall (to order consumables in the required quantity, in a convenient format).

Preparatory operations also include the selection of tools. To carry out the work, depending on the chosen fastening method, you will need the following set:

spatulas of different sizes;
construction knife, stapler;
level, tape measure, pencil;
hammer drill (impact drill);
mixer or attachment for stirring the adhesive solution;
sandpaper (grater);
hammer;
containers for glue, primer, plaster mixtures.

It is customary to pay great attention to preliminary preparation. Leveled walls without defects speed up further installation work, avoiding possible troubles (for example, panels falling off along with the plaster). It is recommended to use foam plastic 3 cm thick inside the rooms, and at least 5 cm thick outside.

Thermal calculation

How thick should foam plastic be for wall insulation? Simply sticking it thicker means not only wasting money, but also reducing the strength of the coating.

The initial value is the permissible value of specific heat loss in a given climatic zone, or the thermal resistance of a building R. For walls in the European part of the Russian Federation, the recommended values are:

South (Krasnodar – Astrakhan – Rostov-on-Don) – 2.8 kW/sq.m.
Black earth strip (Voronezh – Lipetsk – Volgograd) – 3.5 kW/sq.m.
Middle band - 4.2 kW/sq.m.
Boreal zone (Karelia – Arkhangelsk – Naryan-Mar) – 5 kW/sq.m.

In a specific locality and in regions with difficult weather conditions, R can be found from the appendices to SNiP, from the local department of architecture or the Municipal Internal Affairs Committee. For floor R is taken with a coefficient of 1.3; for the ceiling - 1.7. That is, in Moscow, the floor R should be at least 5.5 kW/sq.m, and the ceiling – from 7 kW/sq.m.

The indicated R values are obtained from typical values of the temperature gradient Γ from inside to outside. For example, in the Moscow region it is considered equal to 40 degrees: +20 inside and –20 outside. If Г changes by no more than 1.7 times, the dependence of R on it can be considered linear and taken with the appropriate correction. For example, you want to have +25 at home in Barvikha with -40 outside. G = 25 – (-40) = 65. 65/40 = 1.625. We multiply by it the recommended 4.2 kW/sq.m for the Moscow region, we get 6.8 kW/sq.m. This is the R value that insulation should be calculated at.

Next, you need to know the values of k for various building and finishing materials. What is this k? This is their specific thermal resistance, R of a square of material in a layer 1 m thick, i.e. Through a meter-thick square, at standard G, exactly that much heat will escape. Some meanings are:

Reinforced concrete grade 400 – 2.00 kW/m.
Cement-sand mortar grade 200 – 1.16 kW/m.
Silicate brick – 0.7 kW/m.
Fired ceramic brick – 0.56 kW/m.
The same, hollow – 0.35-0.41 kW/m.
Gypsum plaster – 0.43-0.47 kW/m.
Warm plaster (HS) on foam plastic or expanded vermiculite – 0.057 kW/m.
HS on perlite sand – 0.063 kW/m.
HS on expanded clay – 0.22-0.25 kW/m.
Expanded clay granules 20 mm – 0.16 kW/m.
Oak, laminate – 0.20 kW/m.
Pine, MDF, construction plywood – 0.16 kW/m.
Fiberboard, OSB, plasterboard – 0.15 kW/m.
Polystyrene foam PSB-20 – 0.033-0.035 kW/m.
The same, PSB-25 - 0.035-0.037 kW/m.
EPPS – 0.028-0.032 kW/m.

Next, we determine R of the available construct. Let's say this is a wall, counting from the inside out, of the following design:

Laminate 0.012 m (12 mm);
PSB-20 0.030 mm;
TS on expanded clay 0.020 mm;
A wall made of two clay bricks with a layer of 1 cm mortar - 0.50 m of brick and 0.010 m of mortar;
External cement plaster 0.030 m.

Rn of each layer is calculated using the formula:

Rn = pn/kn, where p – layer thickness in meters; n – serial number of the layer.

We have:

R1 = 0.012/0.20 = 0.06 kW/sq.m;
R2 = 0.030/0.035 = 0.85 kW/sq.m;
R3 = 0.020/0.25 = 0.08 kW/sq.m;
R4 = 0.50/0.56 = 0.89 kW/sq.m;
R5 = 0.010/1.16 = 0.008 kW/sq.m;
R6 = 0.030/1.16 = 0.026 kW/sq.m.

Total R = R1+R2+R3+R4+R5+R6 = 0.06+0.85+0.08+0.89+0.026+0.008 = 1.914 kW/sq.m. This is not enough even for Krasnodar, and already in the middle zone without insulation you will have to freeze, or pay an additional 4.2 - 1.914 = 2.286 kW (approx. 2.3) for heating for each square of the external wall area.

Now let’s calculate the thickness of the external insulation required to bring R to the standard of 4.2 kW/sq.m. We have already found out that we need to retain Rwarm = 2.3 kW/sq.m in the room additionally. We will insulate with EPPS, for which K=0.032 kW/; We take the upper value based on moisture absorption. The thickness P of the insulation is determined by the inverse formula:

P = K*Rwarm

We have: P = 0.032x2.3 = 0.0736 m. Sheathing made of 80 mm EPS or even PSB-25 will allow you to insulate properly, because there will also be plaster on the outside.