Polyfoam has become quite popular material for the insulation of buildings. It is highly efficient and affordable. But before buying materials and starting construction work, it is worth exploring the pros and cons of polystyrene insulation.
Material benefits
Thermal insulation of a building using polystyrene foam (the second name for polystyrene foam) has the following positive aspects:
- Low cost. Compared with other heat-insulating materials, this one will be inexpensive, and you can buy it in almost any store.
- Good thermal insulation performance. Foam insulation gives the same effect as the popular mineral wool and Penoplex. The coefficient of thermal conductivity of all these materials is similar.
- Ease of use. The material is easy to cut. You can work with it without the use of special tools or protective clothing. In addition, the insulation is easily attached to glue and special fungi.
- Light weight and dimensions. Expanded polystyrene transportation will not be a problem. The material is easy to transport on your own. This option allows you to reduce the cost of insulation.
The pluses on which it is worth insulating a house with polystyrene do not end there. The material is not dangerous to humans. It can be used both internally and externally. But when using it is worth remembering the disadvantages. Cons are presented below.
Cons of Styrofoam
Before warming the house with foam, it is worth deciding whether the pluses outweigh the disadvantages of which the material is not small. Among them there are those that prevent the use of a heat insulator for certain structures and buildings. Cons are expressed by the following factors:
- Do not insulate with foam plastic structures, where the material is subjected to severe loads. It has low strength and is destroyed by strong impacts. When building a house, you can use the material where it is reliably protected from loads. For example, you can mount it on the ceiling from the inside of the room.
- Polyfoam is destroyed when exposed to moisture and freezing temperatures. Therefore, the use of material for insulation of a basement or basement is unacceptable.
- Expanded polystyrene belongs to the group of combustible materials. They can isolate a private building at their own peril and risk. But use for public buildings outside and inside may be limited. If the house is checked by official services, they simply will not allow commissioning the building with fire safety violations.
- Polystyrene practically does not let air through. It is possible to insulate a wooden house with polystyrene, but it is worth remembering that at the same time it will lose almost all its advantages. Often, wooden construction is chosen because this material “breathes”. At the same time, a comfortable microclimate is created in the room. Expanded polystyrene blocks the movement of air.
Warming a wooden house with polystyrene, it is worth remembering that it is reliably protected from mold and fungus. To do this, it is necessary to leave a layer between the wall and insulation for free air circulation. This option will allow you to remove moisture from the structure. Most often, warming is performed from the inside. It is not necessary to arrange an air gap from the outside.
Application area
Given the previously mentioned disadvantages, it is possible to choose the use of polystyrene without harming the building. Polystyrene insulation of wooden buildings (if required) is better done from the inside than from the outside. This will protect the material from destruction, and the building from defrosting. It is more reasonable to use vapor-proof material in stone buildings (brick, concrete), but if absolutely necessary, you can also insulate wood.
Stone and block buildings can and should be insulated from the outside. But to insulate wooden houses from the outside with foam is not recommended.
Floor insulation
When used from the inside, the ceiling becomes the main application. Laying into the floor structure is also possible. But when carrying out work, the strength of the material should be taken into account.
- The first use case is common for concrete floors. In this case, the insulation is laid under a cement-sand screed. To prevent foam penetration, the screed is reinforced with a thickness of approximately 50 mm. For reinforcement, special grids with reinforcement with a diameter of 3 to 6 mm are used.
- The second option is applicable for buildings with wooden and concrete floors. In the first case, the insulation is laid in the ceiling or floor between the beams. In the second case, you will have to make a wooden frame, between the lags of which foam is mounted. In this case, the overlap cake increases by eating up the usable room height.
There are two ways to fix the foam on the ceiling. On the frame or without it. The choice of method depends on what material the ceiling is made of and technical capabilities.
Insulating the ceiling, it is worth remembering waterproofing and vapor barrier. Polystyrene balls are not afraid of water, but moisture can accumulate between them. Manufacturers usually are silent about this property. The ceiling in this case should contain the following layers (they are listed from bottom to top, from the side of a warm room):
- the material with which the ceiling is sheathed;
- vapor barrier necessary to protect the insulation;
- insulation;
- floor structure;
- waterproofing (sometimes mounted on top of the ceiling);
- floor of the next floor.
If necessary, insulate the floor, the vapor barrier is also laid from below, and the waterproofing from above. It is important to remember that the first is always located on the side of warm air, and the second on the side of cold air.
Wall insulation
Also, foam is actively used for thermal insulation of the walls of houses from the inside. In this case, steam and water protection are also required. When performing interior decoration, it is worth leaving a small gap between it and the heat insulator to eliminate settled vapor.
But it is important to remember that polystyrene is not the best option for walls. It has an extremely low breathability, so it can create a greenhouse effect in a room. In this case, you will have to take care of the additional forced ventilation device (which is expensive).
Based on the foregoing, we can summarize: polystyrene is an inexpensive material to protect the house, with an impressive list of shortcomings. It is wiser to use it for floors than for walls. If possible, use a vapor-permeable mineral wool in a wooden building.