Improving the thermal insulation of the walls of the house is a necessary stage of construction. Heating costs can be up to 40% of all utility bills. To reduce costs, heat loss must be prevented. In some situations, it is not possible to insulate on the cold side. In this case, foam insulation is often used inside the premises used.
Distinctive features of foam as a material
The considered insulation has a fairly low strength. When exposed to moisture and cold, the material can crumble into small balls. For this reason, foam insulation of the walls of the house is not recommended to be performed outside without a protective lining. Indoors, you can use the method without fear.
Polyfoam as a wall insulation has the following positive characteristics:
- low cost;
- availability, it can easily be bought at almost any hardware store;
- light weight;
- ease of transportation;
- ease of installation;
- good thermal insulation performance;
- safety.
Disadvantages when using the walls of the house from the inside are practically not manifested, since the material is most afraid of moisture and freezing temperatures.
Pros and cons of warming from the inside
Before doing the work yourself, you need to study all the nuances. Thermal insulation of walls indoors is not the right solution from the point of view of a science such as heat engineering. This method becomes only valid if it is impossible to use another. The disadvantages of insulating the walls of the house from the inside are as follows:
- decrease in the useful area of internal premises;
- the measures taken do not prevent the walls from freezing, and therefore do not protect them from destruction;
- the dew point (condensation) is inside the load-bearing wall of the house (high probability of moisture accumulation).
Insulate polystyrene from the inside is only possible if there is a serious need for it. Most often, do-it-yourself work should be performed in the following cases:
- Thermal insulation of rooms in a multi-storey building. To perform the insulation of the apartment with expanded polystyrene from the outside, you will need to hire industrial climbers. Such services are expensive, so you can apply internal protection as an alternative.
- Wall insulation of the house with a new cladding. When doing homework in a private house, it is necessary to take into account the condition of the facade decoration. If the outdoor work is relatively recent, it is impractical to disassemble the lining from an economic point of view. In this case, it is also possible to fix the thermal insulation from the inside of the walls.
Features of the use of polystyrene as a heater
When fixing material from the side of warm air, special attention should be paid to safety. It is worth considering several disadvantages of wall insulation with polystyrene foam, which can be combated at the construction or repair stage. Such disadvantages include:
- flammability;
- low vapor permeability;
- the need for additional vapor barrier;
- the likelihood of a greenhouse effect in the room with insufficient ventilation.
To prevent the risk of fire, all fire regulations must be strictly observed. When choosing a material for thermal insulation of the walls of the house from the inside with your own hands, it is worth giving preference to those types that are highly resistant to fire. The combustibility group is indicated by the letters:
- NG - non-combustible;
- from G1 to G4 - of varying degrees of combustibility.
The higher the number in the labeling, the more hazardous material is offered. In the store it is recommended to choose the polystyrene foam that has the lowest degree of flammability of all those presented. You can also consult with the seller.
To prevent mold and mildew, it is necessary to move the condensation point on the walls from the surface of the connection between the wall and the insulation. The material for thermal insulation is mounted on the wall from the inside with your own hands without any gaps. In this way, condensation problems can be avoided.
The most important task when using polystyrene foam as a heat insulator is to ensure the necessary air exchange. With insufficient ventilation of the premises, the microclimate is disturbed. There may be problems with humidity and internal air temperature. To prevent trouble, you need to think about ventilation at the design stage of the building.
To prevent condensation from occurring, the following methods are used (simultaneously):
- between the wall insulation and interior decoration provide a small ventilation gap;
- a vapor barrier is mounted on top of the insulation;
- carry out measures for the installation of a forced air ventilation system.
If you take into account all the features of the foam as a building material, you can use it for the wall of the house without fear. Do-it-yourself thermal insulation device requires attention to every detail and compliance with the technology of work.
Important! We strongly recommend a gap between the vapor barrier and the finishing layer. Because only this - and no other - way is 100% avoiding the formation of condensate and the inevitable repeated repair.
Wall insulation technology
Before starting work on polystyrene foam inside, do-it-yourself will require a set of preparatory measures. In order for the heat insulator to fit flat against the wall, you will need to prepare a vertical surface. It is carried out in the following order:
- removal of the finishing layer, if any;
- cleaning from dirt, dust, grease and other contaminants;
- leveling the base using putty;
- checking the evenness of the building level;
- processing the wall with a primer that has an antiseptic effect (this way you can protect materials from the destructive action of fungus and mold).
The thickness of the foam sheets is taken depending on the climatic region. In order to find the exact value, you will need to perform a heat engineering calculation. You can use the special program "Teremok", which performs all the actions yourself. To start work, you only need to know the thickness of the wall and its composition. The thermal conductivity of various materials can be easily found on the net.
If it is necessary to increase the protection against cold, often without calculation they take a thickness of expanded polystyrene of 20-50 mm. Before fixing the sheets, a special glue or polystyrene mastic is applied to the base. It is important that the adhesive solution does not contain substances that can destroy the material used. Such substances include, for example, acetone and other solvents. When buying glue, you need to check with the seller if it can be used to fix polystyrene foam.
Insulation sheets are mounted on the wall with dressing. You can offset each subsequent row relative to the previous one by half the width of the sheet. The joints are in a checkerboard pattern.
The glue is allowed to dry for about 3 days, after which they are additionally fixed with dowels-fungi.
After fixing, you need to close the joints between the sheets. To do this, you can use mounting foam. Excess material after solidification is cut with a knife, joints are wiped with a special grater.
Before starting the finishing work after completing the actions with the foam, a number of measures are required. They are carried out in the following order:
- applying glue or reinforcing mesh to strengthen the base for finishing;
- leveling the surface with sandpaper;
- padding;
- installation of a vapor barrier;
- providing an air gap between the vapor barrier and the finish (for this you can use a frame made of wooden battens).
When doing DIY work, it is recommended to choose films as a vapor barrier material. They are cheaper, and their main drawback (creating a greenhouse effect) is not so important when using thermal insulation with low vapor permeability. All the same, there is a need to take additional measures for ventilation.