The modern market for thermal insulation materials offers customers a wide range of quality products. Some of the most demanded and popular are polystyrene and polystyrene. They are often confused, so it is worth figuring out how foam differs from expanded polystyrene in order to choose the most suitable insulation for your home, garage, cellar or shed.
Description of materials
Externally, the materials are similar and they have the same field of application. But there are still differences.
Styrofoam
The material is foamed plastic. This is not a specific insulation, but a whole group. Expanded polystyrene is also a type of foam. There are two types of this material - pressless and extruded. Speaking about polystyrene, they mean the first type.
In the manufacture of insulation, polystyrene is used. The granules of the material are treated with dry steam. They expand due to heat, due to which they adhere to each other. At the same time, micropores remain between the granules, which reduce the strength - even a slight pressure is enough for the insulation to crumble.
Expanded polystyrene
In the manufacture of the material, polystyrene granules are extruded - fused together at a high temperature, and then pressed to increase the strength of the insulation. As a result, molecular bonds arise, due to which it will not be possible to crush a sheet of heat-insulating material by simply squeezing it in your hands. Due to the absence of micropores between the granules, the thermal conductivity increases slightly.
Comparison of Styrofoam and Styrofoam
To choose the optimal insulation for specific purposes, you should take into account the technical characteristics of the material.
Thermal conductivity
This is one of the most important indicators that you need to pay attention to when choosing a suitable thermal insulation material. It depends on it how high-quality and effective the insulation of a house or any other building will become.
Expanded polystyrene is the leader here. Its thermal conductivity is 0.028 W / m * K, while that of foam plastic is one and a half times higher - 0.039.
With high-quality insulation, the heat loss of the building when using expanded polystyrene is significantly reduced.
Mechanical strength
An indicator by which two similar outwardly materials differ greatly. It becomes especially important if it is planned to insulate the walls from the outside, since the insulation will have to withstand certain loads. At the same time, it should not break - any crack will turn into a cold bridge, significantly reducing the effectiveness of thermal insulation. It is necessary to take into account not only compressive loads but also bending loads.
Here, expanded polystyrene also outperforms foam. It can withstand a pressure in the region of 0.4-1 MPa and a bending load of about 0.25-0.5 MPa. Such a significant spread is explained by different brands of insulation, as well as the thickness of the sheets. Similar indicators of foam are 0.05-0.2 and 0.07-0.2 MPa. Therefore, if you need a heater that can withstand rather heavy loads, it is better to give preference to expanded polystyrene - it will last much longer.
High strength allows us to make various products from expanded polystyrene - ceiling tiles, skirting boards and much more.
Ability to absorb water
In damp climates, this parameter must be taken into account. If the insulation is saturated with moisture, its thermal insulation properties will sharply decrease and the efficiency will significantly decrease. Chemical heaters are not subject to decay, they dry quite quickly and return to their original characteristics, but it is better to choose a material that practically does not absorb water.
To determine the hydrophobicity, the thermal insulation material is immersed in water for 24 hours and 30 days. For this, polyfoam absorbs quite a lot of water - 2% of the volume of insulation per day and 4% per month. The micropores between the granules are quickly filled with moisture. Because of this, it is recommended to use the material indoors or protect it with high-quality waterproofing to minimize contact with moisture.
Expanded polystyrene absorbs water much worse - its indicators are 0.2 and 0.4%, respectively - it absorbs moisture ten times worse. The material can be used to insulate the exterior walls of the house.
Refractoriness
When it comes to insulating a wooden building, fire resistance is especially important. When working with any other buildings, you should not forget about it either.
Here, both materials do not appear in the best light. Their flammability indicators correspond to the G2 or G3 classes. The specific characteristic depends on additional impurities that can be used in the manufacture of insulation. In any case, it is enough to bring a match so that they flare up and continue to burn until they are completely burned out.
Shrinkage tendency
Shrinkage is a serious problem when using insulation. If the material changes its shape even slightly, gaps will appear between the sheets, reducing the effectiveness of thermal insulation.
Expanded polystyrene practically does not shrink even after many years of use - this is a very important plus.
Styrofoam can deform slightly if exposed to constant heating - for example, in combination with warm floors or when exposed to sunlight. Therefore, it is recommended to protect it with white UV-blocking plaster.
Scope of materials
Polyfoam and expanded polystyrene can be used to insulate buildings - in general, their scope of use is quite close. An additional plus is the ease of installation and fit, resistance to shrinkage. However, expanded polystyrene is a more popular insulation. It has lower thermal conductivity and resistance to water, better strength. Therefore, it can be used to insulate any surface, including floors.
The foam begins to crumble even under light loads. Rodents love it, they can make a whole network of tunnels in the insulation, reducing the thermal insulation capacity. Therefore, it is better to use it for insulation of walls and ceilings in houses and apartments where pest control is actively carried out.
