Review of polystyrene foam as insulation

Insulation made of polystyrene foam is becoming more and more common in building and remodeling projects. Its great insulating qualities, low cost, and lightweight design are the main reasons for its widespread use. But why is this material so effective, and are there any disadvantages to take into account?

There are two primary varieties of polystyrene foam: extruded (XPS) and expanded (EPS). Both varieties provide good thermal insulation, which lowers energy costs and helps to keep interior temperatures comfortable. They are perfect for use in damp areas like basements and foundations because they are also moisture resistant.

Polystyrene foam also has the benefit of being simple to install. The material fits snugly into a variety of spaces because it is easy to cut and shape. Because it can be applied to floors, walls, and roofs, it is a flexible choice for both new construction and remodeling.

It’s crucial to be aware of a few potential drawbacks, though. Due to its flammability, polystyrene foam needs to be installed properly and with safety precautions. Furthermore, even though it is strong, it can eventually deteriorate when exposed to UV light, so it must be protected when used outside.

All things considered, polystyrene foam is a very good insulator with a number of advantages, but use it wisely and be aware of its limitations. Polystyrene foam can be an important part of your project, whether you’re updating an old house or insulating a new one.

Characteristics

It is hard to find someone who does not regularly come into contact with foam plastic, which is simply light white sheets of polystyrene foam that have been foamed using a non-press technique (polystyrene is another name for it).

The material was initially created by BASF in the middle of the 20th century by polymerizing Styrofoam and adding a foaming agent to the molten mixture at the same time. As a result, 98% of the material was made up of air chambers with thin polystyrene walls.

Foam cells do not experience convectional heat transfer, as is known about gas. Furthermore, because the walls of the chambers are thin, heat transfer along them is negligible. As such, the material that BASF was able to obtain proved to be a very good insulator.

Types of foam are distinguished by sets of letters and numbers. The following is the marking: PSB-S-25 F, where C stands for self-extinguishing, F stands for façade, and PSB denotes pressless polystyrene. The following could appear in place of or next to the letter "F":

• A – regular geometric shape with a smooth edge;
• B – edge with an L-shaped cut;
• R – sheets were cut with a hot string;
• N – can be used for outdoor work.

During the production process, varying foam densities can be produced with varying mechanical strength, stiffness, and resistance to different kinds of exposure indicators. The different grades of insulation are based on the mass of the material per unit volume (kg/m3): PSB-15, 25 PSB, and 35 PSB. PSB-50 is occasionally offered for sale. However, in monolithic construction, its primary use is for the installation of permanent formwork.

Polystyrene foam comes in various densities, each resulting in unique technical and physical characteristics. Table 1 provides a summary of the primary attributes for ease of understanding.

Table 1 lists the primary foam grade indicators.

Foam grade / Indicators	PSB-S-15	PSB-S-25	PSB-S-35
Thermal conductivity, W/(m×°K)	0.043	0.039	0.037
Density, kg/m3	8.0-15.0	15.0-25.0	25.0-35.0
Compressive strength, mPa	0.04-0.05	0.08-0.10	0.16
Bending resistance, mPa	0.06-0.07	0.18	0.25
Flammability class	G3	G3	G3
Vapor permeability coefficient, mg/(m*h*Pa)	0.05	0.05	0.05
Self-extinguishing time after contact with an open flame, sec	4	1	1
Water absorption when immersed in water for 24 hours, %	4	3	2

Manufacturers provide sheets with thicknesses ranging from 10 to 100 mm in 10 mm increments. Any production facility can provide foam insulation up to 500 mm thick for the same cost per 1 m3 if needed. Buyers prefer thicknesses between 40 and 50 mm the most.

This can be explained by the fact that a 5 cm thick foam plastic board can retain heat just as well as a 27 cm thick wood board, 75 cm thick brickwork, and 150 cm thick concrete wall. Housing in central Russia can be adequately insulated with this. Far North regions require 10 cm of insulation, which is thicker.

For length and width, there are two standards: 500 x 1000 and 1000 x 1000. It is occasionally possible to find a 1000 x 2000 size.

Advantages and disadvantages

Foam made of polystyrene has advantages and disadvantages. Benefits are clear:

• low thermal conductivity-0.037-0.041 W/(m · K), comparable to mineral wool, which allows you to effectively warm the structures of the building from brick, concrete, expanded clay concrete, gas strokes, etc.d.;
• ability to maintain performance properties over a wide temperature range: from -50 o C to +75 o C (if there is no contact with an open flame, it begins to deteriorate at +160 o C);
• low cost – refers to the budget type of materials;
• simple installation – there is no need to install the sheathing, as it is fixed with adhesive;
• does not require work experience or special tools when carrying out thermal insulation;
• low specific gravity – does not create a load on the structural elements of the building;
• does not serve as a base for the proliferation of mold and mildew;
• shows inertness to the components of cement-sand mortar, gypsum, weak acids.

There are also minuses, but buyers tend to ignore them. Among the drawbacks are:

• flammability – class G3 (normally flammable). Clarification is necessary here: manufacturers say that the insulation is self-adjacent due to special additives-antipyrene, which is indicated by the marking with the letter “C” (see. photo above). However, this property is demonstrated during experiments only by products of well-known brands: Nova Chemicals, BASF, Polimeri Europa and Styrochem. Russian manufacturers also add fire retardants to the composition, but do not achieve a self-extinguishing effect: the product burns well;

• release of toxic substances during combustion (hydrocyanic acid, phosgene, hydrogen bromide, etc.) as a result of which a person quickly loses consciousness during a fire and dies;
• transition to a fluid phase during the combustion process – spreads across the floor, increasing the area of ​​the fire;
• release of styrene, which is harmful to health, when the temperature rises above +30 o C;

Be mindful: is using polystyrene foam for indoor insulation hazardous? You can’t say when a freelance situation arises, but foam insulation is completely safe for people when there isn’t an extreme (high temperature) or a force majeure (fire).

• short service life – 5-7 years, during which the original thermal conductivity values ​​are maintained, although manufacturers claim the opposite, talking about 30 years or more. Laboratory tests, during which a foam plastic slab that had served for 9 years was removed from the wall, showed that due to destructive processes (the appearance of shells, cavities, increased density and decreased volume), the thermal conductivity coefficient increased almost 8 times;
• amplifies (resonates) indoor noise. Explanations are also needed here, since on the Internet, including Wikipedia, it is stated that polystyrene foam has good soundproofing properties. But it"s a myth. The insulation has a closed cell structure and is light weight. Therefore, it cannot reflect sound waves – there is no mass and absorb noise – the material does not allow air to pass through. On the contrary, high stiffness of the slab and small mass lead to resonance in the region of 500 Hz, t.e. in the very center of household noise;
• instability to most paint solvents – melts instantly;
• Aging intensively under ultraviolet radiation (sun rays), which is heavily hushed up by manufacturers and sellers;
• lack of vapor permeability, although all reference books provide digital values ​​that refute this statement. The problem is solved either by the correct choice of material thickness, which requires complex calculations, or by installing a ventilated facade and roof;
• low mechanical strength – easily damaged during transportation, installation and operation.

The relationship between mice and insulation needs special attention because, in the event that mice are discovered within the home, the foam plastic will sustain the most damage.

Which is better – polystyrene foam or polystyrene foam?

Experts and do-it-yourselfers frequently disagree over whether polystyrene or polystrene foam is preferable for insulation. Visitors to advanced portals will claim that this is the same thing. They will also be accurate. Expanded polystyrene, also known as styropor, is, in fact, the original foam plastic and the archetypal example of the class of foamed plastics from the perspective of chemistry.

Not everything is as easy to understand at the home level because polystyrene foam is linked to materials like Penoplex, TechnoNIKOL, Styrofoam, and URSA, which are made of extruded polystyrene foam but structurally nearly identical to polystyrene foam. Foam insulation and extruded polystyrene foam are easily distinguished from one another because the former is always white and the latter is painted or colored. Furthermore, every manufacturer has their own color, such as "Penoplex" (orange), "TechnoNIKOL" (yellow), "Styrofoam" (blue), etc.

There are minor variations when it comes to their operational characteristics:

• foam has a higher thermal conductivity, which requires a thicker layer of thermal insulation. And this is the loss of usable area of ​​the room when insulating from the inside;
• extruded polystyrene foam has higher strength and rigidity;
• polystyrene foam is much cheaper (about 2,000 rubles./m 3 versus 4,500 rub./m 3 ).

Application area

Foam insulation is used in many different areas of the US economy. For instance, they are utilized to insulate the freezers, refrigerators, isothermal vans, and other appliances from heat. Insulation in construction is achieved by using:

• facades, which allows you to solve several problems at the same time: create effective thermal insulation of the building; protect walls from rain, wind, sunlight and temperature changes; remove the “dew point” from the thickness of the wall, preventing it from freezing (very important for brick and ceramics);
• floors – used for insulation using the “floating screed” method;
• roofing (roofs) – laid on the back side of the roof ("Ventilated roof") and on top ("Non-ventilated roof");
• foundations;
• ceiling (interfloor);
• walls from the inside of the room, balconies, loggias, garages, workshops and other. utility or outbuildings;
• pipelines.

The use of foam plastic in the creation of permanent formwork for the building of monolithic structures is growing.

Since polystyrene foam is inexpensive, easy to install, and has excellent thermal properties, it is a popular choice for insulation in both residential and commercial buildings. The use of polystyrene foam will be discussed in this review along with its advantages and disadvantages, including energy efficiency, moisture resistance, and environmental impact. Homeowners and builders can decide if polystyrene foam is the best insulation material for their projects by carefully considering these factors.

Manufacturers and prices

Due to the high cost of shipping outside of a region or territory, construction foam plastic is produced throughout the entirety of Russia. Thus, discussing particular supplier companies is pointless. The cost of one meter three of PSB-S-15 insulation ranges from 1,790 rubles to 3,900 rubles.

Many international businesses also sell their goods in Russian marketplaces. Some of them come from their factories outside of the Russian Federation, while others are from Russian production sites. Among them are:

• BASF is a German company with branches in Russia;
• Polimeri Europa (Dunastyr) (Italy);
• "Styrochem" (Finland), etc.

With the exception of flammability, products from foreign companies have prices that are 10-85% higher while maintaining the same performance characteristics. Russian foam does not burn; imported polystyrene foam burns and goes out.

Insulation technology

Polystyrene foam is an easy material to insulate a house with for any novice craftsman who knows the fundamentals of thermal insulation work. You will need to assemble a set of tools and buy supplies before you can begin working.

Tools and materials

Supplies you must purchase:

• Styrofoam;
• cement or synthetic based adhesive;
• special mushrooms for attaching foam plastic, the length exceeding the thickness of the plates by 4-5 cm – needed when insulating vertical and inclined surfaces;
• reinforcing mesh;
• polyurethane foam.

Included in the toolkit are:

• level;
• plumb line;
• roulette;
• a knife with a replaceable blade or a hacksaw;
• electric drill;
• glue container;
• mixer attachment for mixing glue.

A universal toolkit for all the house’s structural components. There are subtle differences between the technologies used to insulate walls, floors, and roofs from the inside and the outside. As a result, we shall discuss individually.

façade

The exterior wall of the building is insulated in multiple steps.

Step 1: There is no dust on the wall.

Step 2: Apply a coating of penetrating primer;

Step 3: An insulation profile is attached along the building’s perimeter at the point where the wall meets the foundation or 50 cm above the ground. This profile supports the foam plastic sheets at the bottom of the structure.

Step 4: Mix the glue with a drill and mixer.

Step 5: The insulating boards are covered with the adhesive mixture. There are multiple ways to apply it: in a single layer, in five spots (the center and the corners), in dots or stripes around the edge, or in a continuous layer.

Step 6: After positioning a sheet of foam plastic on the profile, press it up against the wall. You must hold the insulation in place for a short while in order for the glue to solidify. When extra glue appears, use a spatula to scrape it off.

Step Seven. There are two rows of insulation fastened.

Step 8: A drill (perforator) is used to drill holes in the wall for fungi. Each sheet has five: two in the center and three in the corners.

Step 9: More foam sheet fastening to the wall is completed. Fungi are first placed into the holes and secured with plastic dowels.

Step 10: The mesh reinforcement is adhered.

The type of finishing determines how far along the work will go. The reinforcing mesh is covered with decorative plaster. The lathing is put in beneath the siding.

Paula

Insulation is installed on the floor between the joists and beneath the screed. There are multiple steps involved in installing thermal insulation beneath the screed:

• the floor base is being prepared. Full information about the technology for preparing the subfloor is given in the work “Preparing the floor for pouring screed”;
• waterproofing work is being carried out;
• foam boards are stacked tightly against each other. Adjacent rows are mounted staggered, “staggered” – the transverse seams should not coincide. Here you need to pay attention to several points: the sheets are fixed with glue, there should be a technological gap of 1-2 cm between the wall and the insulation, the joints between the plates are glued with tape, the cracks are sealed with adhesive putty;

• the insulating layer is reinforced;
• the screed is poured.

The following is the algorithm for floor insulation on joists:

1. the floor base is being prepared;
2. The subfloor is being waterproofed – details can be found in the material “Waterproofing a wooden floor”;
3. logs are attached;
4. foam is laid;
5. the gaps between the joists and the insulation are foamed with polyurethane foam;
6. the thermal insulation layer is covered with a vapor barrier film;
7. plywood or OSB sheets are attached to the joists;
8. finishing floor being installed.

Walls from the inside

Two technologies can be used to insulate walls from the inside:

• for glue for decorative plaster, painting or “liquid” wallpaper;
• using lathing, if the finishing is ceramic tiles or PVC panels.

Note: Lately, plasterers have completely stopped lathing and have switched to gypsum plaster for paint and wallpaper instead of plaster.

In the second instance, the wall in between the vertical posts is adhered to with foam. Foam is used to fill the spaces created by the insulating boards and the frame. Plasterboard sheets are affixed over the insulation beneath ceramic tiles, or a counterlattice is positioned beneath PVC panels.

Roofs

Depending on the type of roof, foam plastic is used to insulate it in two different ways.

• A horizontal (flat) roof is covered with insulation boards 7-10 cm thick on top, after which it is filled with bitumen and glued with two layers of roofing material.
• The pitched roof is insulated from the back side, in relation to the attic space. 10 cm thick slabs are attached to the sheathing mounted on the flooring under the foam plastic. Here it is important to correctly perform the vapor barrier and create a ventilation gap between the roof and the insulation to avoid condensation.

Aspect	Details
Material	Polystyrene Foam
Thermal Insulation	Highly effective in reducing heat loss
Moisture Resistance	Good resistance to water and dampness
Durability	Long-lasting and resistant to decay
Installation	Easy to cut and install
Cost	Affordable compared to other insulations
Environmental Impact	Non-biodegradable, recycling options available
Fire Resistance	Needs additional treatment to improve fire resistance

Polystyrene foam has shown to be a dependable and effective insulating material for a range of building and remodeling tasks. Because of its superior thermal qualities, buildings can maintain indoor temperatures and use less energy. Significant savings on heating and cooling expenses may result from this.

The lightweight nature of polystyrene foam is one of its most notable qualities. This minimizes labor costs and time by making it simple to handle and install. Its resistance to moisture also guarantees that it works even in wet environments, preventing the growth of mold and water damage.

Even though polystyrene foam has many benefits, it’s vital to think about how it will affect the environment. Because it is a petroleum-based product, improper disposal can lead to pollution and it is not biodegradable. Recycled foam or products with recycled content can all help allay these worries.

All things considered, polystyrene foam is a flexible and efficient insulation option that offers superior thermal performance and simplicity of installation. However, reducing its environmental impact requires responsible use and disposal. You can make an informed choice that best meets your needs for construction or renovation by weighing the advantages and disadvantages of each option.

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