Gas-filled plastics, which externally represent material from foamed cells, are classified as foam plastics. Depending on the production technology and the polymer used, this class includes several types of materials that have different applications. All of them have thermal insulation properties and are non-toxic. The popular PSB-S-25 facade insulation foam meets sanitary and hygienic requirements and is a universal basis for any type of plaster.
General information
With the increase in the cost of energy resources, the actual problem is the protection of the enclosing structures of the premises from the unintentional release of heat to the outside. The low density of the foam provides the material with high thermal insulation performance. Therefore, insulation of facades with foam plastic is a modern solution for saving energy resources. Although this is far from the only area of application for this material.
Also used:
- as a filler in the compartments of ships, which ensures their unsinkability;
- in the manufacture of life jackets, buoys and floats;
- as a material for the production of medical containers that are used to transport donor organs;
- as a protection for fragile goods;
- as a heat insulator in refrigerators and other household appliances.
Types of insulation
There are statistics, which are not confirmed by any regulatory documents, that heat loss through walls is 40%, through the roof - 25%. Therefore, it is possible to achieve maximum protection of housing from heat losses by insulating the walls.
There are two ways to isolate a room from the penetration of moisture and cold air currents: from inside and outside. It is believed that it is possible to protect the wall from freezing and at the same time preserve the internal area of \u200b\u200bthe housing when choosing external insulation. And another advantage of the facade protection of the building is the fact that a condensation zone forms between the internal insulation and the load-bearing wall. And this is an ideal environment for the development of fungus and mold. But a wall protected from the outside retains heat longer and does not cool.
Although there are cases, for example, in the case of a beautiful finish of a house or an elevator shaft, when it is technically impossible to insulate with foam plastic from the outside. Then apply the internal protection of the walls. In addition to foam, builders use other materials.
Types of materials
Popular heaters: mineral wool, polyurethane foam and expanded polystyrene. Mineral wool is mounted only on a metal frame, which then needs to be sheathed with plasterboard sheets, siding or other finishing material. Polyurethane foam has a temporary advantage, since it is applied automatically, using a sprayer. In this case, the material fills all the cracks in the frame, forming a monolithic coating. However, protecting the walls in this way will cost more than using foam for insulation.
Polystyrene foam is made in two ways, resulting in non-pressed and extruded material. Marking PS-1 means that the foam is tile press-made, and PSB-S is a material with self-extinguishing ability. That is, polystyrene with reduced flammability was used in its manufacture.
Quality characteristics
Insulation of facades with foam begins with the choice of material. The main characteristics that you need to know when purchasing insulation are the dimensions of the plates, density and thickness. According to GOST 15588-86, the nominal dimensions of the plates can be:
- thickness in 10mm increments: 20-500mm;
- along the length in increments of 50 mm: 900-5000 mm;
- in width in increments of 50 mm: 500-1300 mm.
But it is allowed, by prior agreement, to produce plates of non-standard sizes. Foam boards are produced with the following density values: 15, 25, 35 and 50 kg/m3. The higher this indicator, the stronger the material and the lower its ability to absorb moisture. Sheet with a density of 35 kg/m3 thickness 50mm is similar in its physical and chemical properties to a material with a density of 25 kg/m3 and a thickness of 100 mm. However, the cost of polystyrene is higher, the greater the density of the insulation.
To select a heater of a certain thickness, it is necessary to take into account a number of factors and make a simple calculation.
Choose the right thickness of material
The thickness of the thermal insulation depends on the value of the standard heat transfer resistance of the outer walls, which is a constant value for different climatic zones, and the thickness of the material of the walls of the building.
For example, the minimum allowable thermal resistance of walls for St. Petersburg is 3.08 m2R/W. There is a brick house, the walls of which are built of one-and-a-half ceramic hollow bricks. The thermal resistance of this design is 1.06m2xK/W. It is necessary to calculate how thick to take the foam for insulation.
To achieve a value of 3.08, it is necessary to find the difference between the normative and existing thermal resistance: 3.08-1.06=2.02 m2xK/W. That is, the value that the foam must have becomes known. Insulation PSB-25 of the highest quality has a thermal conductivity (according to GOST) 0.039 W / (m K).
Based on the formula that the thermal resistance is the ratio of the layer thickness to the coefficient of thermal conductivity of the material, we have: 2.020.039=0.078 m. In this case, PSB-25 foam 80 mm thick should be purchased. This calculation did not take into account the thermal resistance of the plaster layer, whichavailable both inside and outside the building. Therefore, in reality, the foam thickness requirement will be less than 80 mm.
What else can be insulated with foam?
Due to the low water absorption coefficient, the material is often used in places of high humidity. Styrofoam sheets are laid in foundation structures, used in the construction of basement-free houses.
To prevent freezing of the foundation of the house, it is recommended to lay cellular insulation in its horizontal and vertical parts. As sound insulation, foam can be laid in a false wall between rooms. Expanded polystyrene is also used to insulate floors, balconies, loggias. In addition to protecting structures from heat loss, the material is used in refrigeration units.
Styrofoam cost
This section shows the cost of foam insulation class at November 2015 prices.
Expanded polystyrene, made by extrusion, is called penoplex. Such plates are more durable than polystyrene, and their price is much higher. The cost of one plate (1200x600x50 mm) is 183 rubles, in terms of 1 m3 this is 5080 rubles.
On sites selling heaters, such a product name as 50 mm polystyrene is often found. This is an ordinary sheet material with dimensions of 1000x2000 mm. The price of one plate is 180 rubles. Now, in comparison with foam plastic, it is clear that a cube of ordinary foam plastic 50 mm thick costs 1800 rubles, and this is 3200 rubles cheaper than extrusionStyrofoam.
So, a cube of ordinary foam, depending on the density, costs:
- PSB-S15 – 2160 rubles;
- PSB-S25 – 2850 rubles;
- PSB-S35 – 4479 rubles;
- PSB-S50 – 6699 rubles.
Myths that Styrofoam for insulation is harmful
The first fiction is related to the coined term "wall breathing". There is an opinion that when insulating housing with foam plastic, the penetration of water vapor decreases, thereby worsening the microclimate, and high humidity forms inside the room. There is no term "breathing wall" in construction, and the currents of water vapor that actually circulate between the street and the house through the wall are very small. The formation of mold and fungus in the room after the walls are insulated with foam plastic is a consequence of poor ventilation.
The second myth is the environmental friendliness of the material. Expanded polystyrene refers to materials without harmful chemical additives. It is 98% air and 2% polystyrene. It is non-radioactive and can be 100% recycled. Operating temperature: -200…+80 degrees. But expanded polystyrene is exposed to acetone, benzene, so this fact should be taken into account when choosing a paint for the final finishing of the facade.
