We insulate the walls from the inside using Penoplex

If during the cold season the electric heater in the house does not turn off, and mold has grown on the walls due to dampness, it’s time to think about thermal insulation. The most popular method is to line the building with insulating material on the outside.

However, this option is difficult to implement in apartment buildings. Therefore, residents are wondering whether it is possible to insulate the interior with penoplex in order to retain heat in the apartment without disturbing the aesthetics of the building.

In an apartment, using penoplex you can insulate the walls, floor, and balcony.

General information

Previously, foam plastic and glass wool were used for such work. From the point of view of reliability, moisture resistance and heat-saving properties, there are no complaints about these materials. But glass wool contains harmful substances that, if inhaled, can cause an allergic reaction or poisoning. Extruded polystyrene foam developed in Russia is safe for health and easy to use.

There are products from different manufacturers on the market.

Preference should be given to brands whose names are associated with high-quality and reliable building materials.

The influence of production technology on harmful properties

During the creation process, expanded polystyrene is subjected to melting and chemical treatment. It acquires a dense, solid structure and loses its negative properties, i.e. stops releasing any harmful fumes into the air.

Unlike glass wool and low-grade foam, the material obtained as a result of extrusion is environmentally friendly and can be used in rooms where small children or allergy sufferers live.

Adviсe

• To insulate the walls of a wooden house, Penoplex is not recommended, since its high density and the possibility of fire are incompatible with such buildings.
• Before insulating yourself, it is better to watch several training videos or videos from YouTube that were filmed by craftsmen on site, directly during the work.
• For long-term service of the inner layer of thermal insulation, the surface of the walls must be dry and without the slightest suspicion of mold, and before insulating the house, you need to weigh the pros and cons.

Characteristics and properties of penoplex

Depending on the installation location, there are 4 types of penoplex: for roofing, for walls, for foundations and universal. The color is the same, orange, but the design is slightly different. For example, wall panels have ribs to improve adhesion to the surface.

The qualitative characteristics of penoplex make it a universal insulation material.

The main characteristics of the material include:

• low ability to absorb and retain moisture;
• no loss in thermal conductivity coefficient during the service life;
• resistance to water vapor;
• extended service life - up to 50 years;
• flammability class - G1-G4;
• Possibility of installation in rooms with temperatures -50…+75°C.

Finishing

As soon as the reinforcing layer has dried, it must be rubbed with an abrasive float. Then two or three leveling layers of the adhesive mixture are applied, and each of them is dried for 24 hours. The dry surface can be primed and plastered.

Finally. The result of covering walls with penoplex is noticeable immediately. The home becomes warm and dry, heating costs are reduced. If you additionally insulate the floor, roof and foundation with penoplex, the house will be truly energy efficient.

Key Benefits

Along with durability, soundproofing properties and ease of installation, extruded polystyrene foam has an impressive range of advantages.

Permeability

Foam plastic, like many other porous materials, allows moisture to pass through. There are voids inside it, which, when gradually filled with moisture or steam, worsen the thermal insulation properties. Penoplex is free from this drawback due to its integral structure. It absorbs moisture on average 10 times less than foam.

Mechanical strength and safety

The integrity of the structure affects the strength characteristics of penoplex.

With temperature changes and increased pressure during vertical installation, it does not crumble, deform or shrink like glass wool.

The flammability of the material is determined by the manufacturer. Depending on what processing was carried out during its creation, a class is assigned from low to high flammable. When purchasing, you should study the technical description of the goods and choose the safest one.

The undoubted advantage of penoplex is its non-toxicity.

The best option

A comparison of the advantages and disadvantages of various materials allows us to conclude that extruded polystyrene foam is the most suitable option for insulating rooms from the inside, loggias, floors, roofs, garages or verandas.

Medium thickness slabs (40 mm) are conveniently and securely installed on wood, concrete or brick surfaces.

Types of penoplex

Based on technical features and installation location, penoplex is divided into several types:

• “C” - used for thermal insulation of rooms on the ground floors, walls and room partitions;
• “F” - used for insulating foundations and basements;
• “K” - installed on roofing structures;
• “Comfort” - used when arranging loggias and free-standing small buildings;
• “45” (density 35 - 47 kg/m³) - suitable for thermal insulation of industrial structures, used at airfields and in civil engineering.

Main types of penoplex.

Preparing the walls

Before insulation, clean and level the walls.
Before you begin finishing the surface, it must be properly prepared.

Already in a habitable room, the walls are cleaned of old plaster.

But if it is in excellent condition, then the coating can be left.

The cleaned wall is leveled; if necessary, a mesh is used, and a leveling compound is applied on top of it.

Material selection criteria

In order for the insulation to serve for a long time and justify the money invested in it, you should check whether it complies with GOST. Sometimes manufacturers offer products that are made in accordance with their internal requirements, but have passed state certification. In this case, the properties of the material may differ from generally accepted ones and require careful study.

It is recommended to touch the material before purchasing. It should be durable and not deform from light pressure. You should evaluate the storage location of the product, its protection from sunlight and possible exposure to solvents (acetone, petroleum products, etc.).

Before purchasing penoplex, you need to check the certificates of conformity.

The thickness of sheets of the same type must be the same. Pay attention to the fire safety mark. If, as a result of finishing, it is necessary to enhance sound insulation, the layer of material should be thicker.

Recommendations

One of the problems that one often encounters when installing siding is the insufficiently high rigidity of the supporting frame. It is clear that penoplex does not make it possible to use full-fledged fastening, and perforated tapes and long self-tapping screws do not provide rigid fixation of the sheathing and frame.

The problem can be solved by using plastic inserts, as in the photo.

The insert has four needle supports that easily penetrate the foam layer and are attached using a long self-tapping screw or pin

In this case, installation of the frame under the siding can be done directly on the holes in the plastic insert. As a result, the support is rigid enough to hold both insulation and decorative cladding.

Sequence of work

If you decide to carry out the insulation work yourself, it is better to study in advance and subsequently follow the procedure for performing the work.

Insulation calculation

First, determine the required thickness of the sheets. The final consumption of material depends on it. The thermal resistance indicator (in Russia it ranges between 3.5 to 4.6 m*K/W) is divided by the thermal conductivity coefficient of penoplex slabs. The second parameter is found in the characteristics of the material.

After taking measurements of the insulated room, the required amount of material is calculated. When purchasing, it is recommended to make a reserve of 10-15% to compensate for possible losses from defects or installation errors.

Required tools and materials

If work is carried out on the ceiling, scaffolding will be required to avoid the collapse of the structure. In all other situations, a basic set of tools is sufficient:

• drill with hammer;
• hacksaw;
• sandpaper or fine construction grater;
• laser level;
• hammer;
• spatulas of different sizes.

A set of tools for laying penoplex.

Auxiliary materials will also be required:

• dry adhesive mixture for installation of extruded polystyrene foam;
• polyurethane foam;
• reinforcing mesh;
• dowels;
• plaster mixture;
• finishing materials (lining, drywall, etc.).

Preparation

To ensure that the slabs are light, even and dense, before installation, you need to remove old finishing materials, dust and cement residues from the working surface. After this, using a building level, you should check the evenness of the structure and, if necessary, eliminate deviations with putty and plaster. Then the surface is primed.

When it stops being wet, you can start insulating it. There are 2 common installation methods: with glue and with the additional use of dowels. Whichever one is chosen, the slabs are first lightly rubbed with sandpaper to improve adhesion. The glue is applied with a spatula.

During installation, you can lay the finishing material directly on the insulation, or you can use a wooden frame and guides installed at the width of the slabs. The frame method will take more time, but is considered more reliable.

Walls

It is recommended to start insulation from the bottom corner of the wall, slightly moving the slabs at each next level. For reliable fixation, use bitumen mastic, cement-based glue, polyurethane glue or polyurethane foam.

The slabs are attached to the wall using special glue.

After applying glue to the slab, it should be pressed firmly against the wall and held for 1 minute, if necessary driving in dowels in the corners and in the center. The adhesive layer may be uneven, so it is necessary to check the evenness of the installation from time to time using a level. The gaps between the plates are filled with polyurethane foam. When it dries, the resulting mounds are cut off.

Ceiling

As in the case of walls, it can be mounted with or without a frame of guides. If a private house is being insulated, then penoplex is laid on the ceiling from the inside and outside, from the attic side.

In apartments there is no possibility to use the outside, so installation is carried out only from the room.

The ceiling should be cleaned, leveled and primed. Glue is applied to the material and pressed tightly to the installation site. For best fixation, dowels can be used. The seams are sealed with foam.

Finishing

Depending on what decorative material will be used to complete the finishing, the finishing of the insulation is carried out. Reinforcing plaster is applied under the tiles or wallpaper, then a reinforcing mesh is laid, plastered again (the second layer is at least 3 mm) and puttied.

It is permissible not to apply plaster under drywall. When the glue has dried, the decorative sheets are mounted to the insulating structure with self-tapping screws, and the joints between them are puttied. Before gluing wallpaper, the surface should be sanded.

Features of insulation

Finishing material has its own characteristics. Penoplex is valued for several important qualities:

1. High heat capacity . It retains heat perfectly. It consists of many microbubbles. Penoplex has a lower thermal conductivity coefficient when compared, for example, with mineral wool slabs.
2. Lightness of the material . Penoplex weighs almost nothing. They can be used to insulate the facade of a building without fear of loads on the foundation.
3. Low hygroscopicity . It practically does not absorb moisture. Penoplex finishing can be done without waterproofing.
4. Not flammable . Penoplex does not ignite, but smolders and melts a little.
5. Not afraid of fungi, mold.

Penoplex is the name of the brand that produces extruded polystyrene foam. In this case, “Penoplex” is a common noun. It has taken root in the Russian construction segment.

There is one significant drawback. The material practically does not allow air to pass through. It is better to make good ventilation in the house in advance. This rule applies to buildings made of timber or logs.

Interesting! Penoplex is a fairly strong insulation material. Some builders use it as permanent formwork for the foundation. Expanded polystyrene is used in the construction of the blind area of ​​the house.

It is important to correctly calculate the thickness of the insulation before finishing the penoplex. Penoplex slabs have different overall dimensions. The most common size: 585 by 1185 mm (width and length). The thickness of penoplex ranges from 20 to 100 mm.

The need to install vapor and waterproofing

If the outside of the wall is not insulated, experts recommend adding a vapor barrier.

Vapor barrier installation diagram.

This rule does not apply to wood and other “breathable” surfaces. The waterproofing layer is added when installing extruded polystyrene foam using a frame method, with lathing. At the same time, it is secured with a stapler, overlapping, after first checking that the layer is laid correctly. The joints are taped.

Common Mistakes

At first glance, insulation work looks simple. However, inexperienced installers may make mistakes that will not allow them to achieve the required thermal insulation properties or may lead to delamination of the material. Most often, beginners make the following mistakes:

1. The number of slabs is calculated incorrectly or the design stage is completely neglected. There is not enough material or there is a large residue.
2. During installation, moisture is allowed to enter the work surface or the temperature regime is not observed.
3. The place and tools are poorly prepared. This increases the risk of damage to the insulation or contamination of surfaces.
4. They do not follow a checkerboard pattern when laying them. Because of this, cracks form and heat escapes from the room.
5. Glue is applied unevenly or in insufficient quantities.
6. Neglect grinding the material. The grip becomes less strong.
7. Do not fill the seams with foam.

To insulate the joints, fill them with polyurethane foam.

Pros - cons

Any solutions in terms of heat conservation have certain disadvantages or advantages. They are expressed in different costs, complexity of work and availability of materials. In the case of this insulation, there are also both positive and negative aspects. Let's start with the advantages of insulating walls with penoplex from inside the room:

However, this approach to thermal insulation also has a lot of disadvantages. The most significant of them will be:

• The dew point will shift towards the living space. To put it simply, the wall will not be heated by the warm air of the apartment, since it will be covered by a heat shield. It will inevitably become colder and this may cause condensation. The humidity in the room will increase.
• With increased humidity and a cold surface, condensation accumulated on the wall will become an ideal environment for the development of mold and mildew. The consequences of this can be very dire.
• You will have to make repairs in the room, at least on the wall that will be insulated. All the accompanying nuances - dirt, dust, etc. will be a big disadvantage of such a solution.
• The room will become noticeably smaller in size - the design takes up quite a lot of space, despite its seemingly small dimensions.
• The costs of such insulation will not be significantly less than the cost of external work, and the time may be required no less. In addition, you will do everything yourself, which means you will have to spend your free time on this.

With such a set of disadvantages, insulating the walls of a house with penoplex or any other material no longer seems such an attractive option. However, sometimes there is simply no other way.

Myths and misconceptions

To finally decide to install extruded polystyrene foam, it is worth understanding the misconceptions and myths associated with it:

1. Penoplex is harmful to health. It releases toxic substances into the environment. This is a myth, because during initial processing the material becomes denser and loses the ability to release any vapors.
2. Walls must “breathe”, and insulation prevents this. This is a misconception, because if city houses were permeable to air or steam, they would be damp and cold in winter.
3. Using insulation increases the risk of fire. This statement is partly true. To reduce the risk of fire, you should choose a material with a high class of fire protection and additionally treat them with protective substances.

Where is it safe to use polystyrene foam?

1. in places where there are no potential sources of fire;
2. in non-residential premises;
3. use for external insulation of the base, foundation, insulation of a frame house with polystyrene foam from the outside.

As you can see, insulation inside the house is unacceptable, and polystyrene foam installed under the slate will not cause harm only if it is installed in a non-residential attic with good ventilation.

Let us note once again, answering the question of whether polystyrene foam is harmful indoors, it is not the styrene itself that is harmful, but its concentration. Expanded polystyrene is a completely safe decor, but is not recommended as insulation for residential premises.

Conclusion

Sellers of expanded polystyrene have the right to refer to GOSTs and SNiPs when offering their goods, because these standards do not regulate the environmental aspect of the use of this heat-insulating material.

Reviews about penoplex insulation from the inside

Oleg, 36 years old, Moscow: “Our loggia runs along the room and kitchen. They installed double-glazed windows, but in the frosty winters we were still cold, and this also affected the temperature in the apartment. I read the reviews on the forum and chose penoplex for insulation. I did it myself by watching videos on the Internet. I liked that almost no debris was generated during operation. I installed all the slabs in a day, and another 2 were spent on clapboard cladding. The temperature on the loggia is now significantly higher than before insulation.”

Mikhail, 45 years old, Kaluga: “I bought an apartment on the ground floor with a rough finish. I decided to use thermal insulation when screeding the floor. The building materials store recommended penoplex. I was surprised by its weight - the slabs are light, but they are not so easy to break. I placed a reinforced mesh between the insulation and the cement. Installation went quickly and without any difficulties. And I didn’t have to spend money on electric heated floors.”

Fastening methods

Surfaces made of different materials can be insulated in different ways. The process of covering a building includes several steps:

• surface preparation;
• insulation fastening;
• finishing.

In order to perform high-quality thermal insulation, penoplex should be installed correctly. First, the starting bar is screwed strictly horizontally. The bottom row of insulation is laid on it.

It is recommended to install a factory additional element (perforated, metal). You need to buy a strip that matches the width of the insulation and the required number of corners.

Before installing penoplex, a horizontal level is drawn along the walls of the building. The starting bar is screwed to the line. It holds the insulation and maintains the “geometry” of the installation.