Technology of thermal insulation with expanded polystyrene

Contents

• Overview of the characteristics of
  • Overview of the characteristics of
    • Overview of the characteristics of
      • Overview of the characteristics of
        • Overview of the characteristics of
      • Overview of the characteristics of

        The foam or polystyrene foam is obtained from a polymer mass that is exposed to high pressure under high pressure by water vapor. As a result, the polymer beads grow tens of times, and a foam material is obtained. In fact, these are millions of air bubbles enclosed in the finest polystyrene shells, which account for only 2-3% of the total volume of the material. Styrofoam is a firm and sufficiently strong foam, created with one purpose - to keep heat in the room.

        

        Main characteristics of expanded polystyrene:

        1. Thermal conductivity - mineral wool is the main competitor to expanded polystyrene, but if you compare the indicators of their thermal conductivity, it becomes clear that the mineral wool is losing significantly. The level of thermal conductivity of expanded polystyrene can be varied by choosing a material of different density - the denser the structure, the higher the thermal conductivity.
        2. Vapor permeability - ordinary foam has zero vapor permeability, since dense polystyrene shells of air bubbles can not pass through wet evaporation. Extruded polystyrene foam differs from usual, because for its shaping the cutting method is used, which means that the steam can get inside through the cuts.
        3. Moisture absorption - the situation with moisture absorption is somewhat different. Usual expanded polystyrene immersed in water, absorbs 10 times more water than dense extruded polystyrene foam. For this reason, it is recommended to use extruded polystyrene for exterior decoration of houses. To foam has served for a long time and continues to maintain heat, it must be properly protected from wetting.
        4. Strength - extruded polystyrene foam is ten times stronger than usual because it has a denser structure, and accordingly a stronger bond between the molecules. The flexural strength is from 0.4 to 1 kg / cm², while for ordinary polystyrene it is 0.02-0.2 kg / cm².
        5. Sound insulation - many foam plastic sellers claim that it protects equally well both from cold and noise, but this is not true. Air bubbles can only muffle the impact noise to a small extent and only if the foam is laid in a thick layer and in compliance with the technology. With air noise, which usually give us discomfort, the foam can not cope.
        6. Environmentally friendly - there is an opinion that the insulation with expanded polystyrene inside, and in general, the use of this material in the construction of a residential house will be detrimental to human health and the environment. Ecologically, expanded polystyrene is safe, but there are several reservations. First, the material is oxidized in the open air, which happens particularly quickly with conventional non-extruded polystyrene foam. During oxidation, toxic substances are released into the atmosphere: toluene, formaldehydes, acetophenone, ethylbenzene, methyl alcohol, etc. That's why after laying the foam plastic insulation must immediately be covered with insulation and finishing.
        7. Flammability - if you look at the advertising of expanded polystyrene in the construction market, you can see that many manufacturers emphasize the fact that their products in terms of fire safety are harmless than wood. In fact, to ignite a tree you need a lower temperature than for burning styrofoam. But before it burns, it will melt and at the same time emit toxic fumes. If the manufacturer claims that his polystyrene foam is able to decay independently, do not believe it. To be convinced of the falsity of such a statement, it is enough to get acquainted with the Russian GOST 30244-94, which states that polystyrene foam belongs to the group of the most dangerous materials for flammability - G3 and G4.
           Many manufacturers, presenting their products, use the European standards for the determination of flammability by biological, chemical and complex characteristics. Therefore, it turns out that the most dangerous and easily ignitable material is a tree. Toxicity of expanded polystyrene is determined approximately, since it is not possible to accurately compare the products of burning foam and wood. As for the comprehensive check, which can provide reliable information about the product, it simply does not include in the general list of technical characteristics. The consumer receives only a part of the information, that is, an inaccurate chemical characteristic and foggy biological analysis. It should also be taken into account that in time any foam, even with flame retardant additives, literally grows old and loses its quality indicators, including the combustibility class( becoming more prone to fire).
           
        8. Longevity - this indicator depends on many factors, from the quality of the material itself, to the operating conditions and climate. Compliance with the installation technology and the use of suitable adhesive and protective mixtures play an important role. If the insulation of the walls with expanded polystyrene is made by all rules, the material will be guaranteed to last for 25-30 years.

        How to choose EPS polystyrene

        The most important error when choosing expanded polystyrene for insulation is the incorrect calculation of the thickness of the plates. Many people think that the thicker the insulation, the better, but not only does this lead to an increase in cash expenditure, but also shortens the life of the insulation and walls.

        

        Polyfoam - one of the cheapest insulation, with the laying of which you can cope without professional skills. That is why the demand for it is so great, and as demand generates supply, varieties of expanded polystyrene are very, if not too much. An uninformed person will immediately become entangled in such a variety, and he will have nothing left but to trust the sales consultant. On this cleverly play many manufacturers, promoting not what is appropriate specifically in your case, but what you need to sell. Therefore, before you go for foam, conduct a detailed analysis: what will you warm, for what purposes, the climate in your region, the financial possibilities, etc.

        If you need to insulate the walls of the house outside, choose polystyrene PSB-S not less than 40 marks. If you see on the marking a figure of 25 or less, such material is not suitable for any construction work. After determining the grade, select the density of the material - for PSB-C40 it can vary from 28 to 40 kg / m³.Be sure to pay attention to the density, not just the brand!

        

        Helpful Hint: If you are assured that the density of the selected expanded polystyrene is not lower than 35 kg / m³, specify how it was produced. The conventional method makes it possible to obtain a foam plastic with a density of not more than 17 kg / m³, while a better material can be made only by extrusion( strong pressure).

        Finally, break off a small piece from the corner of expanded polystyrene - if the edge breaks off unevenly, and you see small balls on the scrap, then the quality of the product is low. High-quality extruded polystyrene foam breaks smoothly, and on the scrap you will see the correct polyhedra.

        Features of insulation with expanded polystyrene

        Despite many claims to expanded polystyrene, it has been the most popular heater for many years. The reasons for this are more than censures: it is cheap, easily cut, easy to install, long service and well-kept heat. However, the most important thing to remember when insulating is to close the styrofoam layer as soon as possible with insulation to protect it from direct sunlight and oxidation. To do this, use special plaster mixes on a mineral basis for external decoration and plasterboard - for internal. Next, we describe how to use expanded polystyrene to insulate the main parts of the house.

        

        Thermal insulation of the foundation and socle

        As the construction of any house begins with a foundation, let's consider the technology of its insulation in the first place. If you insulate the foundation, then instantly increase the insulation of the entire house, and prevent freezing of the ground. This means that for the insulation of the floor, walls and roof you will need less money, effort and time, and the foundation itself will last longer, as it will not freeze and thaw annually.

        

        Foundation heat insulation technology with expanded polystyrene:

        1. You can warm the foundation during the construction phase of the house and even after putting it into operation. In the second case, the foundation must be completely unearthed all around the perimeter, cleaned of dirt, rust and any stains. If there are remains of roll waterproofing on the outer walls, they must be removed. To warm the foundation, as well as walls, it is possible both outside and inside, but experts all as one advise to do it from the outside.
        2. For the basement and basement insulation, it is better to use extruded polystyrene foam, taking into account when choosing its density and design thickness. The density should be at least 35 kg / m³.
        3. Before fixing expanded polystyrene, it is necessary to waterproof the exterior walls of the basement. Any materials with the exception of bituminous mastic on organic solvents are suitable for this, since it will quickly destroy it upon contact with expanded polystyrene. If you want to use mastics, choose mixtures on a water or polymer basis.
        4. It is now possible to attach expanded polystyrene plates. Use for this special glue, designed exclusively for expanded polystyrene. Apply it along the entire perimeter and a couple of strips in the center, wait a minute for it to become pinched and press firmly against the wall for 2-3 minutes. Do the leveling of the plates to prevent misalignment at the connection points. If you are going to lay polystyrene foam in two layers, fasten the sheets of the second layer so that their seams are offset from the seams of the lower layer by half of the plate( dressing the seams).Fills that remain after fixing the plates, fill with mounting foam.
        5. Even extruded polystyrene foam does not have high mechanical strength and is subject to various damages, including rodent damage. For this reason, after laying the plates from above, you need to attach reinforcing mesh or wooden shields. Fix them with dowels along the perimeter of the foundation to the height of its backfill. If using a mesh, it is necessary to apply cement plaster over it with waterproofing additives.
        6. If you insulate the foundation of a house located on wet ground with a high level of groundwater, it is necessary to make a drain. To do this, a perforated pipe is installed along the perimeter of the house, laying it on a powder of sand and gravel. To fill the foundation in this case you need sand or soft soil.
        7. For the insulation of the plinth with expanded polystyrene, the board must first be glued to the prepared substrate, and after 1-2 days, when the glue solidifies, strengthen the fixation with dowels-umbrellas. Each plate should be reinforced with 3-5 such dowels. To reduce the number of fasteners, umbrellas can be installed in the joints between the plates. To protect polystyrene from atmospheric and mechanical influences, it is necessary to lay a paint net and plaster the surface with a mineral mixture. After this you can proceed to the decorative cladding.

        

        Despite the popular practice, it is better not to insulate the foundation with polystyrene foam - this is not exactly suitable for such operational loads. Specialists recommend replacing expanded polystyrene with stronger analogs: penokleksom or polyurethane foam.

        Wall insulation

        Many people mistakenly believe that there is no difference between the insulation of walls from the outside and from the inside, moreover, it is much easier to insulate walls from the inside, because you can do it at any time of the year and do without equipment for high-altitude work. However, in fact, everything is quite the opposite - experts recommend not to insulate walls from the inside without extreme necessity. A need for this can only occur if the house is of architectural or historical value, or if the insulation of facades with expanded polystyrene is impossible for technical reasons.

        

        What are the problems with internal wall insulation:

        1. The dew point is the place where the cold temperature from the street collides with the heat coming from inside the house - moves inside the room into the space between the heater and the wall. As a result, dampness accumulates there, fungus, mold develops, the wall collapses.
        2. As the wall gradually degrades from moisture, the service life of the building itself is also reduced by several times.
        3. Inside the room, the walls of which are insulated from the inside, there is constantly increased humidity, and if you do not provide additional ventilation of the rooms, the interior trim and furniture will also begin to deteriorate. Moreover, due to changes in the internal climate, the health of residents will suffer.
        4. For insulation of walls from the inside, the thermal insulation layer should be thicker than for exterior works. This leads to increased costs and a reduction in useful internal space.

        All these factors together lead to a rapid destruction of the walls of the house and uncomfortable living, and therefore it is better to immediately heat insulation with polystyrene outside. More useful information about this you will find in the article "Warming the facade of the house with foam plastic".

        Insulation of the floor

        Even if you have insulated the foundation and the plinth, this does not mean that the floor insulation can be neglected. This issue is especially acute for residents of the first floors of multi-storey buildings and owners of private houses. Warming of the floor with expanded polystyrene allows to significantly reduce heating costs, as well as eliminate the causes of "household" diseases associated with hypothermia.

        

        If you work with the floor on the logs, it is better to use PSB-S15 expanded polystyrene for insulation, since the main load will not be on them, but on logs. According to the power for the thermal insulation of the floors on the first floors, 10 cm is required, and for interfloor overlappings - 5 cm.

        

        For the insulation of concrete coatings, a stronger polystyrene foam is required from PSB-C35 and higher. First, a rough leveling is carried out with plates of different power, but experts advise to make an equalizing screed before the insulation. Before laying the insulation plates on the floor, put a waterproofing film. Expanded polystyrene is covered with a 2 cm layer of cement mortar, in which the reinforcing mesh is heated, then a final screed is 5-8 cm thick. The technological gaps around the perimeter are filled with glass fiber or foam.

        Insulation of the attic

        Recently, many have begun to redesign attics into cozy attics, thus increasing the useful living area of ​​the house. But that there was really warm and comfortable, the walls and ceiling must be warmed up. In this case, there is no particularly strong load on the surface, but the insulation is subjected to a different effect. Since the attic is under the roof itself, all warm air from the house rises there, and if you do not create a serious barrier to it, it will simply leave the house, and you will spend a lot of money on heating. For the same reason, the attic is always several degrees warmer than on the lower floors of the house.

        

        The ceiling in the attic is more susceptible to condensation than other ceilings in the house, so it is necessary not only to insulate it qualitatively, but also to take care of the vapor barrier and ventilation.

        Heat insulation of the attic with expanded polystyrene takes place according to more stringent requirements. This topic is considered in more detail in the article "Roof insulation with foam plastic".

        Below in the video - heat insulation with polystyrene in the attic:

        Styrofoam can be a great help for creating a warm home for many years, but only if you carefully study all aspects of its use.