Insulating a house from a foam block: how to properly and better sheathe the outside of the facade walls using penoplex, as well as what else can be used and is it necessary?

Insulation of foam blocks is a mandatory measure, thanks to which it is possible to significantly improve the performance characteristics of residential buildings and significantly extend the service life of the entire structure. Foam block is a type of cellular concrete that is characterized by its low weight, large size, high sound/heat insulation properties and many other advantages.

Despite the fact that the foam block can be finished with any materials and its heat saving indicators are quite high, insulating the walls with special materials still makes sense. Initially, insulation of walls made of foam blocks was not intended due to the fact that the material already has high thermal insulation characteristics, but different materials are used to protect the block itself and improve its properties in harsh winter conditions.

Another reason for the need to insulate the block is its fragility - foam concrete has sufficient strength, but is afraid of external influences and becomes more prone to deformation under the influence of moisture and frost.

What are the advantages of insulating a house from foam blocks from the outside:

Saving internal space.
Maintaining the integrity of blocks.
Effective protection of walls from moisture and freezing, which significantly extends the life of the building.
Eliminating the possibility of condensation accumulating inside the material is to remove it outside and remove it with air.
No cold bridges, more efficient heat conservation.
Increasing the efficiency of thermal insulation by 20-30%.
The frame created for installing the insulation can serve as the basis for finishing.

To insulate foam concrete, light options are used - mineral wool, polystyrene foam, etc.

Is it necessary to insulate the façade walls?

Foam blocks were invented specifically for the construction of single-layer walls.
Due to their good thermal insulation properties, such buildings in warm countries do not require additional thermal insulation .

But due to the fact that Russian winters are characterized by their harsh weather, experts advise additional insulation of the house from foam blocks.

If you look from the other side, foam blocks are a fragile material and when exposed to certain weather conditions they freeze and absorb moisture. In order to prevent this, the walls are insulated from the outside.

As a final finish on top of the insulation, it is better to use lightweight structures. Decorative brick is not suitable for these purposes; most builders use plaster or cover the house with siding .

Should I do it?

The reasons for insulating a house are different, for example, climatic conditions, insufficient wall thickness, the desire to reduce heating costs, etc.

Foam blocks have low thermal conductivity - 0.2 - 0.4 W/m*ºK. This characteristic is several times better than the thermal conductivity of sand-lime brick. Therefore, some doubt the advisability of insulating walls.

In fact, facade insulation is necessary for the following reasons:

Foam concrete blocks, due to their porosity, have a high vapor permeability rate. If insulation is not performed, the dew point will be inside them, which will lead to a decrease in the service life of the building.
Insulation will significantly reduce energy costs for heating.

Important! Thermal insulation of a foam concrete house is not something you should skimp on!

You can avoid insulation if the building is not planned to be used in winter. However, the outside of the walls will still have to be finished, since the negative effects of moisture will soon ruin the walls.

Outside or inside: which is correct?

Thermal insulation measures are usually carried out outside. Internal insulation will complicate the installation of hanging structures on the walls.

The thermal insulation layer can be installed both from the inside and outside, but the first option is usually chosen for the following reasons:

When performing thermal insulation work inside, the usable area of the room is significantly reduced, while external insulation does not affect the internal dimensions in any way.
This allows you to extend the service life of load-bearing structures. This way they are reliably protected from adverse weather influences.
If insulation is done inside the house, then the wall outside remains cold and moisture penetrates into it. When insulating from the outside, moisture does not collect inside the wall.

What is the best time to carry out work?

A certain amount of time must pass before the outside of the house can be insulated. After all, at the factory, immediately after production, foam blocks are sent into sealed packaging and delivered to the construction site. Provided that the building is erected quickly, the blocks still retain their original moisture level upon completion of construction. And if you insulate it right away, the blocks will absorb all the water and steam.

Because of this, vapor permeability decreases and in cold weather, when heating devices are turned on inside the building, the moisture inside the walls moves to where the partial pressure is lower (in the direction of the house, that is). When moisture reaches the interior, it collects on the surface and the wall becomes damp. The foam blocks freeze, the insulation actively rots and the performance characteristics of the entire building deteriorate significantly.

After completion of construction, it is advisable to cover the facade with film and allow all moisture to evaporate for 3-5 months, which depends on the humidity/ambient temperature.

It is ideal when a house is built in the spring and insulation is carried out at the end of summer. Then the foam blocks have time to dry completely and the efficiency of further work increases.

Materials: what is better to use?

There are several materials that are most often used for insulation:

Mineral wool. It has excellent vapor permeability, but shrinks if installed incorrectly. Some types of this insulation can only be installed using protective equipment. This type of insulation must be securely closed, since wind and other external influences can spray small particles. Capable of accumulating moisture, so it cannot be installed in bad weather. The most popular type of mineral wool is stone (basalt) wool.
Polystyrene foam or polystyrene foam. They are excellent thermal insulation materials, although they do not have vapor permeability. They do not shrink, are not afraid of cold weather, have a water-repellent effect and are a sound insulator. But polystyrene foam does not tolerate exposure to direct sunlight, which means that it must be covered with decorative materials. In addition, mice love polystyrene foam, and if they make their nests in this thermal insulation layer, their quiet life will end. Penoplex insulation will avoid these disadvantages, but will cost much more.
Polyurethane foam. Another material that is often used for insulation. The advantages include excellent adhesion to any surface, no need for leveling the wall, priming and construction of the frame, ease of transportation, light weight, it does not weigh down the walls and roof, improved thermal insulation and strength characteristics of the wall during installation, improved sound insulation, resistance to temperature changes , seamless, no fasteners required. Disadvantages include fear of exposure to sunlight, ultraviolet radiation destroys the material, and fire hazard during prolonged exposure to high temperatures.

Typically, a material is chosen that does not block air circulation through the walls of a foam block house. Therefore, it is better not to use polystyrene foam and penoplex.

The cheapest option that meets this requirement is mineral wool insulation.

Insulation with this material should be carried out strictly according to technology, taking into account its characteristics.

An important requirement for thermal insulation materials for outdoor use is good vapor permeability. The walls will become damp if moisture cannot escape.

Let's start from the roof

It is better to start this type of work from the roof. After all, it is through it that significant heat loss can occur. They occur if the floors are not insulated.

You can insulate a house from above in various ways. In particular, if you want to arrange a living space in the attic, you will have to insulate the inside of the roof. At the same time, the price of the work carried out will, of course, increase.

The roof of the attic floor must be insulated

If you do not have such plans, then it is quite possible to get by with insulating only the ceiling, that is, the attic floor.

For this purpose, cardboard must be laid in several layers between the beams. You need to pour a thick layer of sawdust on it. Instead, you can put mineral wool. But, in this case, you will have to attach a waterproofing film over it.

In the photo - thermal insulation of the attic floor using mineral wool

To get a good result, you need to ensure that the insulating material covers the entire surface of the attic floor. If mineral wool is used, it should also cover the beams themselves. In addition to this, boards must be laid on top of the thermal insulation layer so as not to damage the insulation when walking.

The use of foam plastic or penoplex and plastering using “wet” technology

This technology makes it possible to carry out insulation and finishing work on foam block walls as economically as possible . The principle is to stick the insulation material and then plaster the surface.

For work you will need the following tools:

screwdriver;
a bucket or other container for glue;
a “comb” spatula for applying the adhesive mass;
wide spatula for plastering;
hammer, construction knife;
roller, brush;
glasses, respirator, gloves;
hammer drill, electric drill;
building level, tape measure.

Materials you will need:

foam boards;
fiberglass mesh;
perforated profile;
special umbrella dowels for foam concrete;
dowels for mounting the profile;
foam glue;
deep penetration primer;
mixture for plastering work.

Preparatory work

Before starting the main work, all communication cables, drains, ventilation should be removed, and wastewater should be removed. The surface of the walls is cleaned of dirt and then thoroughly dried.

It is advisable to carry out insulation during the dry period, when the foam concrete blocks are completely dry without moisture inside. All cracks and crevices should also be repaired. If the damage is extensive, it is necessary to consider strengthening structural elements or strengthening the foundation.

The cleaned walls are treated with a primer composition intended for external use, deep penetration. It is advisable to repeat the procedure 2 times. Priming is necessary for adhesion of the heat-insulating material to the foam blocks.

Attaching the supporting profile

The profile is needed to support the foam so that it does not slide down. It also protects against rodents entering the insulation. The profile is fixed around the perimeter of the base with dowels or self-tapping screws. Work is carried out strictly according to the level.

Laying slabs

According to the instructions on the package, the adhesive composition is prepared. Using a notched trowel, glue is applied to the slabs from the back side of the material. The layer should evenly cover the entire surface of the foam plastic (or penoplex) plate.

If the walls are not too smooth, the glue can be applied to the material in “patches”, but in this case it is necessary to pass the solution along the perimeter from the edge of each slab. The boards are glued starting from the bottom in a checkerboard pattern. Strongly protruding parts are removed.

Fastening slabs with “umbrellas”

A day or two after gluing the slabs, it is necessary to supplement the fixation of the slabs with umbrella-type dowels. The holes are drilled approximately 1.5 cm longer than the dowel length. They are fastened in the corners and in the center of the slab.

Plastering works

To protect the insulation and give a finished look, the wall surface is plastered. A fiberglass mesh with a layer thickness of 3-5 mm is glued on top of the insulation for reinforcement. The mesh must be completely immersed in the adhesive composition.

After the mesh has dried and smoothed, a layer of primer is applied to the surface. After it has dried, you can begin finishing.

By following the sequence described above, you can independently insulate a house made of foam blocks from the outside with polystyrene foam and plaster the facade using the “wet” method.

Video description

In our video we will look at how polystyrene foam is produced, is polystyrene foam harmful and where is it used?

Roll or slab insulation is secured with special nails with wide heads Source saucyintruder.org

a windproof membrane is applied and can be fixed to the insulation with disc nails;
finishing materials are installed.

The plaster is applied in a slightly different way:

The walls are primed, chips and cracks are covered;
A reinforcing mesh is installed around the perimeter, with an overlap of 20-30 cm at all corners.
The plaster is prepared according to instructions, applied to the wall with a spatula, and evenly distributed.
After drying, the mesh is reattached and decorative plaster is applied.

Using mineral wool boards for siding

Another insulation option is a “ventilated facade”. It consists of fixing mineral wool and covering the walls with siding or facade panels with a gap for ventilation.

All work can be divided into several stages.

The work does not require special qualifications; everything can be done with your own hands.

Surface preparation

The wall made of foam blocks is cleaned of dust and other contaminants. If there are significant irregularities, they should be eliminated. This should not be difficult, because foam blocks are easy to process.

All interfering elements are dismantled. For example, wall mounts. The surface must be clean.

By stretching the line diagonally from the upper corners to the lower, the differences in the wall are determined. This will allow you to find out at what height the sheathing will be mounted.

Installation of sheathing and mineral wool slabs

To do this, you can purchase either a metal profile or a wooden beam . Both options will do.

Important! The wooden beam should be treated with antiseptics before fastening, so it will last much longer.

Sequencing:

The beam is attached along the perimeter of the wall. The distance between the bars (or profiles) must be less than the width of the insulation boards in order for the insulation to fit tightly, without gaps.
The lower transverse beam is fixed. It is needed to support the first row of slabs, and will also protect the insulation from penetration by rodents from below. Window and door openings are sheathed with timber around the perimeter.
After installing the sheathing, the vapor barrier material is attached with a stapler. For example, polypropylene or polyethylene film, foil vapor barrier, etc.
The insulation is installed and secured with umbrella-type dowels. It is advisable to make more than one layer so that the next layer overlaps the joints of the previous layer. The installation of the slabs begins from the bottom with gradual movement to the top in a checkerboard pattern.
A waterproof film is stretched over the insulation. Serves to protect mineral wool from getting wet. It is also attached with a stapler.

Important! You cannot make holes for dowels with an impact hammer. Switch to the drill. Drilling should occur without impact, because foam concrete is very fragile.

Siding installation

Insulation of walls made of foam blocks from the outside ends with the installation of siding:

The counter-lattice is installed and the siding is attached to it with self-tapping screws. You cannot screw in the screws all the way; you must leave a gap of approximately 2 mm.
It is needed to ensure that the material does not warp during expansion. The panel has holes for connection. The self-tapping screw is screwed into its center. No holes are made in the panel itself.

You can cut siding panels with a regular hacksaw with a fine tooth.

Installation of insulation

After the question of how best to insulate a house made of foam blocks has been resolved, you need to figure out the installation process. When using polystyrene foam , work is carried out in the following order:

Before starting work on insulating a house, you need to thoroughly clean and sand the surface, prime all walls, and pay special attention to all joints.
Then the metal frame is placed. The distance between vertical drains corresponds to the width of the insulation. Galvanized plasterboard profiles or antiseptic-coated wooden beams can be used as the basis of the frame.
It is better to fasten the rack without drilling or dowels; the screws must be screwed in immediately. The foam block is very fragile and friable.
After installing the frame, the insulation is cut, glued to the wall, fixed using a windproof membrane to protect against steam and moisture, all joints and fastenings are puttied.

We analyze the theoretical aspects

Insulation of a foam block from the outside is carried out according to the same rules and standards as when working with any other material. But when choosing a material and technology, the characteristics of foam concrete are taken into account.

When insulation from the outside must be carried out:

If the walls are less than 37.5 centimeters thick.
Provided that the masonry has a large thickness of mortar, when heat can escape through the seams.
Use of high-density blocks of grade D500 and higher in the construction of the building.
If the width of the blocks is less than 30 centimeters.
When filling load-bearing frames of structures with foam concrete products.
If the builders made mistakes - if they used cement mortar instead of special glue in the masonry, made thick seams, etc.

In other cases, thermal insulation work is carried out at will, but one way or another provides better heat conservation. In order to accurately determine the need for work, it is advisable to calculate the heat transfer resistance of the walls and compare them with the indicators specified in the standards.

As an example, we can take the construction of a house from D500 brand blocks with a thermal conductivity coefficient of 0.14. The thickness of the building wall is divided by a coefficient - 375 millimeters (0.375 meters) divided by 0.14 and the result is 2.68. SNiP II-3-79 “Construction Heat Engineering” states that the standard value is 3.2 (for Moscow and the surrounding region).

That is, the thickness of the walls is not enough to ensure high-quality thermal insulation of the house and foam concrete requires additional measures. True, you need to remember to take into account the heat transfer resistance of the internal and external cladding. These indicators are added to the resulting value.

When do you need to insulate?

The feasibility of thermal insulation of foam concrete walls causes debate among construction engineers, many of whom believe that this material does not need to be thermally insulated. One cannot but agree with them, given the high heat-protective characteristics of this material.

However, if the wall thickness was chosen incorrectly, the construction technology was violated, or due to shrinkage processes, cracks formed in the wall structures, creating cold bridges, the owner of such a house will still have to resort to thermal protection.

The next important point to achieve effective thermal conditions is to choose a place for installing insulation :

outside;
inside;
on both sides of the load-bearing wall.

Experts insist that the best thermal protection scheme is external.

Advantages of the external thermal protection scheme for a foam block building:

saving useful space in living rooms;
long service life of foam blocks;
protection against freezing of load-bearing structures;
the dew point moves to the outer street part of the blocks, from where it is removed by air flows;
Easy to install, no need to take things out of the room.

Disadvantages of internal thermal protection:

the insulation installed in the room prevents the wall from receiving heat from the in-house heating system;
the dew point moves to the inner edge of the wall, condensation forms on it, promoting the development of biocontaminants in the form of mold and subsequent destruction of the walls;
heat-insulating building material absorbs household moisture vapor and increases weight, which loads the load-bearing structures of the house.

In a situation where it is necessary to insulate temporary structures with a block thickness of up to 20 cm in order to ensure sufficient temperature in the rooms, insulation can be performed on both sides - external and external. Then the outer and inner cakes are selected so as to bring the dew point closer to the street.

Designers of foam concrete houses do not recommend installing ventilated heavy thermal protection systems on such walls , since foam concrete may not hold them together with the external decoration.

In what cases can it be done?

The most important indicator that confirms that a foam concrete house does not need external thermal protection is the low actual heat loss of the house.

Foam blocks are designed to work without thermal insulation, but still, if the house remains cold, it is necessary to conduct a survey of the facility for energy efficiency . It is clear that laboratory tests should be carried out by specialists during the cold season.

Special devices will help determine the real heat loss in the house, and if it does not exceed 10%, then there is no need to install thermal protection in the house, so as not to additionally load the walls. In addition, such an examination can accurately determine the sources of cold entering the premises (this could be cracks in the walls, an uninsulated roof or floor).