Expanded polystyrene is a popular insulation that is used in private housing construction. The material has a lot of advantages. We will analyze the use cases and technology for the installation of expanded polystyrene.
What it is?
For the production of expanded polystyrene, a polymer mass is used, which is subjected to steam treatment under high pressure. The result of processing is an increase in mass in volume.
The foam has numerous air bubbles that have thin shells. In fact, polystyrene foam is a foam that has sufficient strength and hardness to retain heat. In everyday life, polystyrene is called polystyrene. The technology for obtaining the material involves filling styrene granules with gas dissolved in a polymer base. This is the common basis of production technology for the two materials, but the materials have distinctive characteristics.
Conventional foam uses ordinary natural gas to fill the granules. Fireproof options are filled with carbon dioxide. There are still options for vacuum foam, in which there is no gas component at all.
For example, granular components can be distinguished externally from the foam, while expanded polystyrene is a more uniform material. If you break the foam in half, many granules are formed. Expanded polystyrene does not have this quality. Polyfoam is cheaper, which is a significant help with external insulation of buildings. Expanded polystyrene has the best mechanical strength.
The material is successfully used as a heater of walls outside and inside the foundation of the house. It weighs little, can be used as thermal insulation of concrete, brick, foam concrete and wooden walls.
Polystyrene insulation of wooden walls has a limitation due to the fact that the foam has a greater tightness than facade wood. Expanded polystyrene itself does not rot. Since the material is completely synthetic, it is biologically neutral to the appearance of mold and fungi.
To date, expanded polystyrene is characterized by convenience and affordability. The main advantage of the material is the indisputable heat-insulating properties. Polyfoam differs in durability and convenience in work. It is the perfect choice for brick and concrete walls. When working with material, it is important not to forget about the features of wood.
Expanded polystyrene has two main varieties:
- Extruded. It is a non-pressed material that is manufactured using equipment such as an extruder. Some manufacturers call this variety extrusion.
- Extrusion material is a polymer mass processed in a slightly different way, having a more uniform structure. Usually they make one-time packaging for products and disposable tableware.
- There is also extruded polystyrene foam, which is characterized by increased strength.
- Autoclaved polystyrene foam is an extrusion variety, but is rarely mentioned by manufacturers.
- Free polystyrene foam is a popular variety that is relatively fragile, but buyers are attracted by the final cost of the material.
In general, polystyrene foam is a material with ambiguous characteristics. Advantages and disadvantages of the material are vigorously discussed by both amateurs and professionals in the construction industry. We will analyze them in more detail.
The main characteristics of expanded polystyrene are:
- Thermal conductivity. Its level can be compared with indicators of mineral wool. Expanded polystyrene is of different densities, and mineral wool has standard values. Choosing a dense polystyrene foam, you can significantly increase the thermal conductivity of the material.
- Vapor permeability. Conventional foam is characterized by zero vapor permeability. Polystyrene casings do not have the ability to transmit moisture. Some extruded polystyrene foam options have excellent vapor permeability characteristics. For its molding, cutting is used, therefore, through cuts, steam can enter the material.
- Moisture absorption. The situation with this characteristic is such that ordinary polystyrene foam, placed in water, absorbs tens of times more water than the extruded version. Therefore, it is recommended to use extruded polystyrene for facades. And this foam needs to provide high-quality protection, otherwise wet material will not properly retain heat.
- Strength. If we compare ordinary polystyrene foam with extruded material, the latter has higher strength characteristics. This option has a high density, and therefore, a stronger bond between the smallest granules. The bending strength of the first option is from 0.4 to 1 kg / cm. sq. Regular polystyrene shows values from 0.02 to 0.2.
- Soundproofing. Many people think that polystyrene is a good protection from the cold. and from the noise. However, due to the airy structure, the material only muffles impact noise a little. For sound insulation from impact noise, the material must be laid in several layers, observing construction technologies. More discomfort is usually caused by airborne noise. Even when the foam thickness is sufficient, it is not an obstacle to airborne noise.
- Environmental friendliness. Some non-professionals believe that insulating with polystyrene at home from the inside will adversely affect human health. But the environmental safety of expanded polystyrene is proven by appropriate tests. It is not for nothing that it is recommended to cover the insulation with insulation and surface treatment. If the material is left outdoors, especially non-extruded, it will release harmful constituents into the atmosphere. However, their concentration is not so high as to cause any harm to humans or the environment.
- Combustibility This is also a controversial characteristic, since many consider polystyrene to be safer than wood. In order to catch fire, a tree really needs small temperature indicators. Polystyrene foam requires high temperatures to ignite. But before the open fire, the material melts and emits toxic smoke. At the same time, polystyrene foam is not capable of independent attenuation, although some manufacturers claim the opposite. According to domestic regulations, all polystyrene foam are among the most hazardous combustible materials.
European standards are different from domestic, therefore the values of the combustibility characteristics are different.
No modern additives will improve this quality, since any materials undergo aging. Quality indicators, including combustibility, decrease over time, expanded polystyrene becomes susceptible to burning. Scopes of expanded polystyrene are often limited by these qualities.
Expanded polystyrene has proved to be an excellent basement insulation. The layout of the material requires a pre-prepared site. In this case, both single-layer and two-layer laying is allowed. After installation, polystyrene foam is poured with concrete mortar. Next, the structure is built in the usual manner. The method allows the use of concrete screed at the same time for the base of the floor without the construction of the basement.
If polystyrene foam is used for basement, then it is possible to achieve high-quality insulation of foundations. This is true for the northern regions. At the same time, both horizontal and vertical laying will save from freezing. The creation of protection for external walls involves the mandatory digging of a trench with a width of about a meter. Depth is determined by the depth of freezing of the soil. Plates are laid along the foundation and filled with soil. This insulation option is suitable for a wooden house. It is better to insulate the walls in the apartment from the inside of the room.
Expanded polystyrene has shown itself well as a heat insulator for utilities. Now it is already known for sure that through poorly insulated communications there is a heat leak up to 30 percent. Expanded polystyrene began to be used for pipelines, ventilation, cables and other lines. The use of expanded polystyrene helps to ensure that the lines can be laid at a shallower depth, which reduces labor costs.
The material showed itself well as an insulator of refrigerated rooms, freezers, refrigerated display cases. For industrial installations, an indicator of moisture absorption and thermal conductivity is important. Traditional heat insulators have more modest indicators.
Expanded polystyrene does not have any restrictions. The material has been successfully used to insulate floors, walls and partitions. 5 cm thick plates play the role of both a heat insulator and a sound insulator, as they reduce the level of impact noise. The technology of laying the material involves the complete sealing of the joints, as well as the mandatory coating of the plates, which can be wood-based or concrete substrates.
Expanded polystyrene is also suitable for roof insulation. For this purpose, boards with a thickness of about 7 cm are used. In this case, it is customary to lay bitumen waterproofing on top of the material.
The technology of work involves the installation of polystyrene foam on the back side of the surface. Condensation will be controlled by a ventilated cavity, which must be foreseen.
The foundation is also insulated with polystyrene foam. Since this is the basis of the building, the durability of the entire structure depends on it. The issue of thermal insulation of the foundation is a priority, especially in regions with a harsh climate. Expanded polystyrene is often used as a formwork. This option significantly reduces the consumption of more expensive building materials. Let us consider in more detail the technology of external wall insulation, which can be done with your own hands.
Subtleties of work
It is customary to fix polystyrene foam outside the house. Technology involves the transfer of the dew point. In addition, if you glue the material from the outside, inside the useful area will remain. External insulation with expanded polystyrene will increase the heat in the building by half. Installation of plates can be carried out under siding or under plaster. But before gluing them, the work surface must be properly prepared.
Surfaces must be cleaned from dirt, paint, plaster. If necessary, the verticals are aligned. With your own hands, insulation plates are easy to stick on the walls. In addition to glue, expanded polystyrene can be fixed with plastic dowels with a wide hat.
In order for the quality of thermal insulation to remain at a decent level, it is important to fix the plates tightly to each other. For the convenience of work, the technology involves mounting plates from the bottom up. This is important, as the top plates may shift down due to the slowly hardening adhesive mixture.
For better fixation of the plates, experts recommend installing the frame . If the boards are glued directly to the wall, a reinforcing mesh can be installed on top. It should be anti-corrosion, suitable for exterior decoration. The reinforcing mesh will contribute to better stiffness of the insulation, so it will be less susceptible to damage. In addition, if the insulation is glued over the facing layer of the plaster, a reinforcing mesh is also needed. She better hold this layer.
After the adhesive mixture has completely hardened, the insulation is covered with a leveling primer. Any finish is mounted on top of the primer. It should be noted that external thermal insulation should be carried out in dry and calm weather. The ambient temperature should be at least 5 degrees.
In addition, each subsequent facing layer is applied only after the previous one has completely dried. Only in this case can we talk about the observance of technology and the long service life of the installed thermal insulation.
Expanded polystyrene is actively used in private construction for brick and wooden walls. Thermal insulation technologies for these types of bases vary.
If we talk about extruded polystyrene foam, which is used for external insulation, it is worth considering that the material does not pass air at all. Therefore, during improper work, moisture will accumulate between the wall and the insulation layer. To eliminate this, a small gap should be left between the facade and polystyrene foam. The circulating air will dry the walls, and excess moisture will be removed.
When carrying out work, it is worth considering the tendency of wood to rot. In the first stages of warming, it is important to exclude possible cold bridges. Through these areas, the appearance of moldy formations can be triggered. Expanded polystyrene for wooden walls can only be used by the curtain wall method. It is also worth considering that wooden houses themselves have good thermal insulation qualities.
Warming of a wooden house may be necessary if:
- after prolonged use, the walls of the house began to let air through;
- violation of the surface layer;
- from the joints, the walls are clearly blown;
- the log walls began to crack.
The whole process of work can be divided into stages:
- preparatory stage;
- installation of a vapor barrier;
- installation of expanded polystyrene;
- installation of decoration.
The step of preparing a wooden surface can be divided into the following works:
- removal of old paint;
- drying out;
- checking the base material for joint density;
- if necessary - sealing joints;
- processing and impregnation of wood.
The last point is of great importance, therefore, at this stage it is important to choose high-quality products.
Installation of a vapor barrier is carried out at the point of contact of wood and insulation. Vapor barrier is a membrane film that consists of three layers. The basis of the film is reinforced polypropylene. On both sides, polyethylene fiber is applied over it. Such vapor barrier will perfectly protect the inner surface from steam and condensate, which will come from the heat-insulating material.
The vapor barrier can be four-layer. A reflective layer of aluminum foil is added to its inner surface. This is an additional thermal insulation, as well as protection against steam. Vapor barriers vary in density. This value affects the quality properties, as well as the price tag.
The technology of laying the vapor barrier involves the installation of a film both along and across the insulation boards. It matters a lot which side to lay the film on. This point must be carefully studied in the installation instructions, since the process depends on the manufacturer.
Reviews about expanded polystyrene are mostly positive. Users write that for private construction this material is recommended by professionals. Professional builders note the convenience in work and the excellent quality of the material. Inside the apartments, polystyrene foam is often insulated with balconies.
Most users note easy installation of the material. You can insulate the house in order to reduce heating costs, especially if the housing area is decent.
Expanded polystyrene is not suitable for finishing slopes, nor is it a very good choice for roof insulation. The material is not very safe in terms of combustibility. Relatively small fires in rooms decorated with polymeric materials lead to poisoning by toxic volatile products.
In addition, polystyrene foam, according to users, nevertheless eat insects, as well as rodents. Although other users have successfully used the material to insulate the roof.
- Cover the polystyrene foam reliably from the sun, rain and snow. Material can completely collapse even from a small sunlight.
- Do not use expanded polystyrene for insulation inside buildings. In this case, it is worth considering the high combustibility of this material. Polystyrene foam products will cause great harm to human health. In addition, the thermal insulation of the walls from the inside leads to the rapid accumulation of moisture, resulting in fungi. Because of them, various diseases arise.
- It is necessary to study in more detail the properties of expanded polystyrene, if the choice fell on this particular insulation. Expanded polystyrene is poorly studied precisely as a building material. The heat-insulating qualities of the material are good, but it appeared on the market not so long ago, therefore it is not known how the material will behave during prolonged use.
For how to insulate the basement of the base with polystyrene foam, see the video below.