Insulation with expanded polystyrene: options for use and laying technology

Expanded polystyrene is a popular insulation that is used in private housing construction. The material has a lot of advantages. Let us examine the options for using and laying polystyrene foam.

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, expanded polystyrene is a foam that has sufficient strength and hardness to retain heat. In everyday life, expanded polystyrene is called polystyrene foam. The technology of obtaining the material involves filling styrene granules with a gas dissolved in a polymer base. This is the general basis of the production technology for the two materials, but the materials have distinctive characteristics.

Conventional foam uses regular natural gas to fill the pellets. Fire resistant options are filled with carbon dioxide. There are also options for vacuum foam, in which there is no gas component at all.

For example, outwardly, granular components can be distinguished from foam, while polystyrene foam is a more homogeneous material. Breaking the foam in half creates a lot of granules. Styrofoam does not have this quality. Polyfoam is cheaper, which is a significant help for external insulation of buildings. Expanded polystyrene has the best mechanical strength.

Thermal insulation of wooden walls with polystyrene has a limitation due to the fact that polystyrene has a greater tightness than facade wood. The expanded polystyrene itself does not rot. Since the material is completely synthetic, it is biologically neutral against mold and mildew.

At the moment, expanded polystyrene is characterized by convenience and affordability. The main advantage of the material is its indisputable heat-insulating properties. Polyfoam is durable and easy to use. It is an ideal choice for brick and concrete walls. When working with material, it is important not to forget about the peculiarities of wood.

Expanded polystyrene has two main types:

• Extruded. It is an unpressed material that is made using equipment such as an extruder. Some manufacturers call this type of extrusion.
• Extrusion the material is a polymer mass processed in a slightly different way, having a more homogeneous structure. It is usually used for disposable food packaging and disposable tableware.
• Still exists pressed expanded polystyrene, which is characterized by increased strength.
• Autoclave expanded polystyrene is an extrusion variety, but is rarely mentioned by manufacturers.
• Pressless expanded polystyrene is a popular variety that is relatively fragile, but buyers are attracted by the final cost of the material.

In general, expanded polystyrene is a material with ambiguous characteristics.The advantages and disadvantages of the material are vigorously discussed by both amateurs and professionals in the construction industry. Let's take a closer look at them.

The main characteristics of expanded polystyrene are:

• Thermal conductivity. Its level can be compared to that of mineral wool. Expanded polystyrene comes in different densities, and mineral wool has standard values. Choosing dense polystyrene foam, you can significantly increase the thermal conductivity of the material.
• Water vapor permeability. Conventional foam is characterized by zero vapor permeability. Polystyrene casings do not have the ability to transmit moisture. Some variants of extruded polystyrene foam have excellent vapor permeability characteristics. Cutting is used to form it, so steam can enter the material through the cuts.

• Moisture absorption. The situation with this characteristic develops in such a way that ordinary polystyrene foam, placed in water, absorbs tens of times more water than the extruded version. Therefore, it is recommended to use extruded foam for facades. And this foam needs to provide high-quality protection, otherwise the wet material will not properly retain heat.

• Strength. If we compare ordinary polystyrene foam with extruded material, then the latter has higher strength characteristics. This option has a high density, which means that the bond between the smallest granules is stronger. The flexural strength of the first option is from 0.4 to 1 kg / cm. sq. Normal polystyrene shows values ​​from 0.02 to 0.2.

• Soundproofing. Many people think that styrofoam is also a good protection against the cold. and from the noise. However, due to its airy structure, the material only slightly dampens impact noises. For sound insulation from impact noise, the material must be laid in several layers, observing construction technologies. Airborne noise usually causes more discomfort. Even when the foam is thick enough, it is not a barrier to airborne noise.
• Environmental friendliness. Some non-professionals believe that insulating a house with styrene foam from the inside will have a detrimental effect on human health. But the environmental safety of polystyrene foam has been proven by appropriate tests. It is not in vain that it is recommended to cover the insulation with insulation and surface finishing. If the material is left outdoors, especially non-extruded material, 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.

• Flammability. This is also a controversial characteristic, since many consider polystyrene foam to be safer than wood. In order to catch fire, the tree really needs a small temperature reading. Polystyrene foam requires high temperatures to ignite. But before an open fire appears, the material melts and emits toxic smoke. At the same time, expanded polystyrene is incapable of self-attenuation, although some manufacturers claim the opposite. According to domestic standards, all polystyrene foam are among the most hazardous materials in terms of flammability.

No modern additives will improve this quality, since any materials are subject to aging. Quality indicators, including flammability, decrease over time, expanded polystyrene becomes susceptible to combustion. The areas of application of expanded polystyrene are often limited to these qualities.

Expanded polystyrene has proven to be an excellent basement insulation. The layout of the material requires a previously prepared site. In this case, both single-layer and two-layer styling is allowed. After installation, polystyrene foam is poured with concrete mortar. Further, the structure is built in the usual manner.The method makes it possible to use a concrete screed simultaneously for the subfloor without constructing a basement space.

If expanded polystyrene is used for the basement, then high-quality insulation of the foundations can be achieved. 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 the outer walls involves the obligatory digging of a trench about a meter wide. The depth is determined by the depth of soil freezing. The slabs are laid along the foundation and covered with soil. This insulation option is suitable for a wooden house. It is better to insulate the walls in the apartment from inside the room.

Expanded polystyrene has shown itself well as a heat insulator for utilities. Now it is already known for sure that up to 30 percent of heat leaks through poorly insulated communications. Expanded polystyrene began to be used for pipelines, ventilation, cables and other lines. The use of expanded polystyrene ensures that the lines can be laid at shallower depths, which reduces labor costs.

The material has shown itself well as an insulator of refrigerating rooms, freezers, refrigerated display cases. For industrial installations, the indicator of moisture absorption and thermal conductivity is important. Traditional heat insulators have more modest performance.

Expanded polystyrene does not have any restrictions. The material is successfully used for insulation of floors, walls and partitions. Plates 5 cm thick 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 assumes complete sealing of the seams, as well as the obligatory coating of the slabs, which can be chipboard or concrete bases.

The technology of work involves the installation of polystyrene foam on the back side of the surface. The formation of condensation will be controlled by a ventilated cavity, which must be provided.

The foundation is also insulated with expanded polystyrene. Since this is the foundation of the building, the durability of the entire structure depends on it. The issue of thermal insulation of the foundation is of top priority, especially in regions with a harsh climate. Expanded polystyrene is often used as formwork. This option significantly reduces the consumption of more expensive building materials. Let's take a closer look at the technology of external wall insulation, which you can do yourself.

It is customary to fix polystyrene foam outside the house. The technology implies a transfer of the "dew point". In addition, if you glue the material on the outside, the useful area will remain inside. External insulation with expanded polystyrene will increase the heat indicators in the building by half. Installation of slabs can be carried out under siding or under plaster. But before gluing them, the work surface must be properly prepared.

Surfaces must be cleaned of dirt, paint, plaster. The verticals are aligned if necessary. It is easy to stick the insulation plates on the walls with your own hands. In addition to glue, expanded polystyrene can be fixed with plastic dowels with a wide head.

For better fixation of the plates, experts recommend installing a 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 outdoor 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 on top of the facing layer of plaster, a reinforcing mesh is also needed. It will hold this layer better.

After the glue mixture has completely solidified, the insulation is covered with a leveling primer. Any finish is mounted on top of the primer. It is worth considering that external thermal insulation should be carried out in dry and calm weather. The ambient temperature must 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 it is possible to talk about the observance of technologies and a long service life of the installed thermal insulation.

If we talk about extruded polystyrene foam, which is used for external insulation, it is worth considering that the material does not allow air to pass through at all. Therefore, if work is done incorrectly, moisture will accumulate between the wall and the insulation layer. To exclude this, a small gap must be left between the facade and the expanded polystyrene. The circulating air will dry out the walls, and excess moisture will be removed.

When carrying out work, it is worth considering the tendency of wood to rot. At the first stages of insulation, it is important to exclude possible cold bridges. Moldy formations can be provoked through these areas. Expanded polystyrene for wooden walls can only be used with the curtain wall method. It is also worth considering that wooden houses themselves have good thermal insulation qualities.

Insulation of a wooden house may be necessary if:

• after prolonged use, the walls of the house began to leak air;
• there is a violation of the surface layer;
• the walls are clearly blown from the joints;
• the log walls began to crack.

The whole process of work can be roughly divided into stages:

• preparatory stage;
• installation of a vapor barrier;
• installation of expanded polystyrene;
• installation of finishing.

The stage of preparing a wooden surface can be divided into the following works:

• removal of old paint;
• drying;
• checking the base material for the tightness of the joints;
• if necessary, sealing of joints;
• processing and impregnation of wood.

The installation of the vapor barrier is carried out at the point of contact between wood and insulation. The vapor barrier is a membrane film that consists of three layers. The basis of the film is reinforced polypropylene. Polyethylene fiber is applied on both sides on top of it. Such a 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 aluminum foil layer is added to its inner surface. This is additional thermal insulation as well as protection from 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 the film both along and across the insulation plates. It is very important 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 of expanded polystyrene are mostly positive. Users write that professionals recommend this material for private construction. Professional builders note the ease of use and excellent quality of the material. Balconies are often insulated with expanded polystyrene inside apartments.

Most users note the easy installation of the material.It is possible to insulate the house in order to reduce heating costs, especially if the housing area is decent.

Expanded polystyrene is not suitable for finishing slopes, it is also not a good choice for insulating roofs. The material is not very safe in terms of flammability. Relatively small fires in rooms lined with polymer materials lead to poisoning with poisonous volatile products.

Experts recommend:

• Protect the Styrofoam from sun, rain and snow. The material can completely collapse even from a small ray of sunlight.
• Do not use polystyrene foam for insulation inside buildings. In this case, it is worth considering the high flammability of this material. Combustion products of expanded polystyrene will bring enormous harm to human health. In addition, the thermal insulation of the walls from the inside leads to a rapid accumulation of moisture, as a result of which fungi appear. 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 insulation. Expanded polystyrene is poorly studied precisely as a building material. The thermal insulation qualities of the material are good, but it appeared on the market not so long ago, so it is not known how the material will behave during long-term operation.

For information on how to insulate the basement base with expanded polystyrene, see the video below.