Characteristics and properties of expanded polystyrene in questions and answers

Extruded polystyrene foam and mice or rats how do they behave with it?

Mice and polystyrene are a moot point. The topic has long been discussed, but there is no single answer. Opinions of people differ directly in the opposite and if you generalize everything, you can meet such opinions:

• Do not eat. As soon as the house was sheathed with polystyrene foam, not a single rodent settled in the house, although before that they had to live every year. Their material repels and they leave.
• They do not eat, but gnaw, only in those cases if it becomes an obstacle to water and food. Granular polystyrene foam is especially affected.
• They eat even if pieces of material are lying around the building.
• Mice often make their nests in this material because it is warm and dry.
• Expanded polystyrene of various brands has different characteristics, so some manufacturers give a one hundred percent guarantee that their material will not be damaged by rodents. One of which is the brand Styropen. The secret is in production technology with the processing of granules with synthetic paraffin, and mice do not like it.

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The density of the foam, what is it and what does it affect?

Density is a value denoting the ratio of weight to its volume. It should be borne in mind that it is air that has thermal insulation properties, and not the polystyrene from which the foam is made. Accordingly, the higher the density, the greater the polystyrene material and less air. With an increase in the density coefficient, the insulating characteristics fall, but the price increases noticeably. Polyfoam is produced in four versions of this value, according to GOST.

Styrofoam grades:

• PSB-S 15 (up to 15 kg / cubic m.). Fragile material, used only in areas that do not require mechanical stress, for example, insulation and insulation of a vertical wall.
• PSB-S 25 (up to 25 kg / cubic m.). More durable material, which is more convenient to install, because it crumbles less, is used to warm the facade.
• PSB-S 35 (up to 35 kg / m3). Resistant to loads, easy to transport, used for insulation of socles and foundations.
• PSB-S 50 (up to 50 kg / cubic m.). The most durable and expensive material, can withstand significant loads (roads, parking lots).

The density of the foam affects:

• Strength in deformation or compression.
• Bending strength.
• Thermal conductivity.
• The ability to absorb moisture, although it does not so much absorb it.

It must be borne in mind that expanded polystyrene is made not only in accordance with the requirements of GOST, but also according to the technical specifications, in connection with this, the density may actually turn out to be different for the material within the same brand.

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PSB-35S 50mm polystyrene equivalent to brickwork?

The ratio of the heat-insulating properties of various materials can be determined by the value of the coefficient of thermal conductivity. The higher the thermal conductivity, the faster the room will cool.

For PBS35S expanded polystyrene, it is 0.038 W / m * K. And for ordinary clay bricks, the thermal conductivity varies between 0.384 - 0.814 W / m * K. We get a 10-fold difference in the thermal conductivity of materials.Consequently, a 20mm thick PBS35S polystyrene plate will provide the same thermal insulation as 200mm brickwork, while a 50mm PBS35S corresponds to a half-meter wall thickness.

Accordingly, you can calculate the ratio of the walls from:

• tree - pine along the fibers of 0.18 W / m * K;
• foam concrete, depending on the density - 0.1-0.38 W / m * K;
• aerated autoclaved aerated concrete in a dry state 0.09-0.12 W / m * K.
  More details: https://techno.techinfus.com/en/voprosy-i-otvety.html

More details: https://techno.techinfus.com/en/voprosy-i-otvety.html

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How does the degree of insulation depend on the thickness of the polystyrene foam?

The degree of insulation of the room is directly dependent on the thickness of the insulation. And calculated by the formula R = p / k, where

• R - heat resistance standard for the region;
• p is the thickness of the material;
• k is the coefficient of thermal conductivity, which depends on the density of the material.

For expanded polystyrene, it is:

The heat resistance standard for the region is taken from SNiP 23-01-99 "Climatology".

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What density foam is better to use for sound insulation?

Polyfoam in itself is not an effective soundproofing material. But it can only be included in sound-absorbing or reflective structures. Foam with a density of 20-25 kg / m3 is used for noise insulation of interior and interroom partitions and ceilings, as well as a filler for doors and various lightweight panels. The insulation made of polystyrene foam panel with a rigid outer lining with cardboard is able to reduce the noise level by 2-5 decibels. In addition, the foam on a rigid base more effectively copes with shock sound vibrations, intercepting up to 95% of the sound.

In addition to thickness, the surface shape of the soundproofing panel is extremely important. The classic and most effective profile is equilateral pyramids directed by vertices to the sound source.

Partially, such specialized coatings on the ceiling can replace polystyrene facing panels with a relief pattern. Their effectiveness is much lower, but when using them there is no need for an additional suspended or stretch ceiling.

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How many years will the polystyrene insulation serve to warm the cellar in the ground if it is buried with a concrete slab?

I highly recommend the use of extruded polystyrene foam. Its service life for quality manufacturers is 40 years. And the scope is just the bleaching of the basement and the underground part of the foundation of buildings. Conventional polystyrene foam in an aggressive environment without external protection can lose its heat-insulating properties after 12-15 years.

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Does polystyrene foam adhere well to Ceresit CR65 waterproofing?

In the instructions for use, which is posted on the manufacturer’s website, it follows that the waterproofing layer of Ceresit CR65 can be used as a base for applying plasters and laying tiles. Therefore, although there are no direct indications, the Ceresit CR65 polystyrene board base is quite suitable.

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At what temperature can foam be glued?

The temperature at which the facade is insulated with foam does not depend on the insulation, but on the glue used to fix it. For example, the manufacturer recommends using Ceresit CT 83 adhesive to perform work in the temperature range from 0 to 30. There are some nuances of using the adhesive mixture at high temperatures. It is necessary to knead small amounts of the client to keep it in a constantly closed container. Eating too much water from the finished mixture will evaporate and it will lose its elasticity; re-adding water is not recommended. Mix a new portion of the solution.

More details: https://techno.techinfus.com/en/voprosy-i-otvety.html