Characteristics of the foam as a building material
Polystyrene foam, which is produced according to GOST 15588-86, is a white, odorless homogeneous substance. The structure of foam are dispersed polymer systems as they combine polymers and gas enviroment. Air cell diameter is about 0.02 mm. Cells are separated with a very thin film of polymer material. Depending on what kind of structure and form of the cells have the properties of the foam are different.
Plastic foam is used in construction since last century, due to its characteristics: non-toxic, environmentally friendly, good insulation and sound absorption capacity, convenience and easy usage. The foam is a perfect heat insulating material. It does not decompose under the influence of microorganisms, fungi.
However, there is a group of chemical compounds that can not only significantly reduce the quality of the foam, but also lead to its total destruction. These include: organic solvents (solvent paints, acetone, turpentine, acetic ethyl ester), saturated hydrocarbons (e.g., alcohol), oil (various resins, gasoline, kerosene).
The disadvantages of foam sometimes rank as highly flammable material However, these characteristics are consistent with the requirements of state standards, and the material was so many times tested.
The main functions of the foam in construction is insulation. In some climatic conditions, for instance in the Far North, insulation is the most important detail for house building.
As an insulation material expanded polystyrene can be used in building facades as middle layer. The main condition is that the surface of the insulated structure does not exceed 800C.
In modern cities there is a tendency of insulating walls and facades of buildings foam. Material attached to the wall with special anchors and then covered with wire mesh.
Moreover, foam is used for insulated pipes, vegetable storage, industrial refrigeration, transport wagons, vans and roofs.
Basic requirements for thermal insulation of buildings
A warm safe home is everyone's dream. How can you achieve perfect results, planning to build or repair ready building? Speical knowledge in similar sphere is must.
What is insulation? It's a special additional design, which helps to protect the walls, windows or roof from a variety of climatic conditions, and at the same time prevents the loss of heat generated inside the room.
Anyone can see that the degree of thermal insulation depends on the material properties, which control the insulation. The more closed pore structure of the material with air and gas, the lower the heat conductivity it may have. For example, metals, granite easily conduct heat, that's why they are considered poor insulators. The leader in building insulation is of course foam.
There are several types of heat exchange. Convection can be observed when the temperature difference in areas where heated surface contacts with cool air (the surface of the walls, windows, radiators).
To indicate the conductivity of the material there is used some unit that is called the coefficient of heat transfer. It is counted by measuring its thermal energy which passes through the building material in an area of 1 m2 at a certain temperature.
Insulating properties of the material depend not only on its density but also the humidity. The higher humidity value is, the worse heat-insulation quality is. Water is a good conductor of heat, i.e wet material gets characteristics of the filler. Here comes the conclusion that the insulation material should always be dry.
The next important aspect to calculate the thermal insulation characteristics of the structure is that it is necessary to take into account the different intensity of heat transfer in different areas. Thus, to calculate the total heat transfer resistance, this index must be summed with the inner wall surface, middle layer and an outer surface. The most suitable indicators are: the temperature difference between the inner surface of the wall and inside the building must be no more than 60.
Calculation of foam insulation
Polystyrene foam is virtually waterproof. The quantity of absorbed water is relative to the weight of polystyrene that ranges 1.5-3.5% a year. On the other hand, air permeability of polystyrene greatly exceeds its water permeability, i.e the wall "breathes".
Temperature doesn't have negative influence on the physical and chemical properties of the polystyrene. At temperatures up to 90°C polystyrene does not change its properties even over long period of time.
The objectives of the insulation with expanded polystyrene (Styrofoam)
- Calculation of foam insulation has only advantages.
- Reducing the cost of installation and construction work
- Saving heating energy
- Reduction in the cost of heating systems
- Increase usable space of the building by decreasing the thickness of the structural walls
- Improving thermal comfort of the room
- The environmental safety of a building
Expanded polystyrene (foam) has a high insulating ability that is superior to the known traditional building materials. Moreover, it can ensure a long life of any building, regardless of climatic conditions.
Calculation of insulation foam
The required insulation thickness is determined by the climatic conditions and the purpose of the building, in addition, measures for protection against condensation and energy conservation must also be taken into consideration. Indicators of polystyrene insulation (foam) are shown in the table below:
m x ° C / W
W / m ° C x
For example, to ensure the minimal insulation for industrial buildings for heating 20°C, the thickness of styrofoam should be for the roof - 80 mm, for the walls - 60 mm.
Sound insulating properties of polystyrene
The inhabitants of modern cities in the pursuit of all sorts of comforts have created an environment that often adversely affect their physical and psychological state. One of the common problems - is an increased level of noise. Natural noise (whistling of the wind, the creaking of wood, the voice of the bird, etc.) affect people positively, but the common noise of city can bring to the madness. Which is the answer to this dilemma?
Engineers know that sound insulation depends on the quality of floors, walls and room dividers. Another important factor is quality of the noise. It can be transmitted through air, then it comes to air sound insulation. It means, the distribution of sound waves doesn't dependent on the mechanical structures. The source of noise are different (during walking, falling objects and etc.), in this case it comes to impact noise insulation. If the noise source is a vibrating surface one should speak of its structural form.
All of these elements for a comfortable life must be neutralized or reduced to the lowest level. This procedure is not possible without the usage of special sound-absorbing and insulating materials, in particular foam.
Styrofoam plates are glued to the wall, applied by a sputtering method, or placed in the middle of the composite plate or panel. In the latter case, the insulation becomes wall foundation.
Some scientists believe the foam is a perfect material not only for sound insulation, but also weakens the effects of magnetic fields.
The use of polystyrene foam for the construction of the foundation and the base buildings
If the house is designed properly, work on its construction performed efficiently, you will live in such building for a long time. But all this can soon disappear if you do not take care of the proper foundation of the house.
There are several methods of house construction. Whichever of them was used, it should be kept in mind that the solidity of the foundation does not ensure reliability and longevity. During winter, the water accumulated in the soil begins to freeze. It is known that when freezing its size increases. Together with water, the sozes of soil also change.
Clay sags in some places, some may have excessively high pressure and as a result the structure of the foundation breaks, and small cracks appear on the walls. Surely, the crack is not a reason leave the house. You will have to save money for repair to get rid of the effects of swelling soils. Sometimes these efforts are in vain.
On the other hand, buying or building a house, you might want to use the underground part of the building for a gym, laundry room, a billiard room or a lounge. In order to make the place comfortable that will not bring to excessive usage of energy, it is necessary to provide reliable thermal insulation. For such purposes polystyrene foam is mainly used.
The foam as part of enclosing structures and pavement
Foam is mainly used for insulation of walls of old buildings or as a thermal insulation layer in the process of construction of new buildings.
Nowadays, the problem of energy conservation is urgent. In European countries appropriate programs are organized many villages and small town have strick rules about energy conservation.
Insulation foam is attached both to the outer and the inner side of construction. It should be kept in mind that in this case insulation properties are somewhat different. The outer wall is subjected to the direct influence of the environment, which is accompanied by changes in temperature. But it doesn't mean that inner layer is of higer quality. Insulation foam skips steam so that moisture does not accumulate, i.e the wall is dried naturally. .
If the sheets of insulation are fixed from the inner side, the outer wall remains unprotected. Due to temperature condensation is formed. This gradually destroys the insulation, so it will not last long. If the insulation is conduct in buildings with complex designs, or of historical value in order to protect the pristine view of the facade, it is installed inside the building.
The leader among the other types of insulation (mineral wool, wood, concrete, concrete, masonry) is surely polystyrene. 40 mm of expanded polystyrene insulation replace 140 mm wood, 232 mm concrete and 860 mm of bricks.
In buildings that are just being built facades with insulating layers are used. There are several ways of building walls. The layered structure can be made at the factory.
The foams are used in road construction. To prevent the destruction of the road surface polystyrene foam is used in the compound. It allows to increase the life of the road, reduce the thickness of the layer that protects from the cold.
The use of foam in the construction of pavements
In our climatic conditions the road surface can be easily damaged. There are different reasons; first, the top layer or the base may too weak. As a result of mechanical stress, sudden changes of temperature and many other conditions can bring to gradual destruction.
The most severely damaged roads cause soils. When exposed to moisture or cold, they may expand unevenly. As a result there appear cracks and holes.
To prevent the influence of heaving soils on the quality of the road there are used a variety of additional layers of foundation. The most effective one is extruded polystyrene foam.
This brings to a decrease in the thickness of the layer that protects from cold. You must know that in some areas of frost protection layer can be more than one meter, which also adversely affects the condition and quality of the road.
The next road quality can also be adjusted using the cover of expanded polystyrene. The height is determined by the follwowing parameters: the subgrade should not strongly wetted, and the road should not be cpvered with heavy snow. Thermal insulation foam reduces the thickness of the mound and prevents freezing of the soil.