What is polyurethane foam, what components it is made of, types of material, technical characteristics, pros and cons, features of the choice of insulation and equipment for its spraying, installation technology.
Advantages of polyurethane foam
The technical characteristics of polyurethane foam have determined its main advantages as a heater. In addition to low thermal conductivity and ability to sound and waterproof, the material has the following advantages:
- High level of adhesion … The material adheres to any surface - wood, glass, brick, metal. Even the oiliness of the coating will not interfere with the "sticking" of the polyurethane foam. Also, the curvature and shape of the surface on which it is applied does not affect the adhesion properties of the insulation. It does not need to be pre-prepared or processed with any formulations.
- Simple assembly … Due to the fact that polyurethane foam is applied by spraying, its consumption is minimal. There is no need to adjust and trim the material while fixing to the surface. Also, you will not need to use adhesives during operation, with the exception of fixing the tile polyurethane foam.
- Ease … Polyurethane foam does not load the building structure, does not put pressure on the foundation. This is especially true when insulating old houses and roofs.
- Strengthening walls … In addition to excellent thermal insulation, polyurethane foam is also able to strengthen the structure and give it additional strength.
- Resistance to temperature extremes … For this heat insulator, temperature drops from -150 to +150 degrees are not terrible.
- No seams and cold bridges … Polyurethane foam allows you to form a homogeneous mass on the walls, in which there will be no seams and cold bridges that allow low temperature air to pass through.
- Resistance to biological effects … This material is not susceptible to rotting, decomposition, fungal attack and does not attract rodents.
- Environmental friendliness … After polymerization, polyurethane foam does not emit toxic substances into the air.
Disadvantages of polyurethane foam
Despite the abundance of advantages of polyurethane foam, it also has quite significant disadvantages that must be taken into account when choosing this insulation. Let's consider them:
- Low vapor permeability … This quality is especially inherent in rigid types of polyurethane foam. This negatively affects the microclimate in a room insulated with such material. If you use rigid polyurethane foam for thermal insulation of the attic, then its walls will become damp, mold and mildew will grow along them.
- Instability in front of the rays of the sun … Ultraviolet light is detrimental to insulation. It significantly degrades its characteristics. Therefore, immediately after installation, polyurethane foam must be protected with finishing materials when it comes to the facade or external walls.
- The need for special equipment for application … Such professional equipment is quite expensive. However, you can rent it or buy non-professional equipment for household use.
It is worth noting that if you do not have the skills and you doubt your abilities, then it is recommended to contact a specialist in the application of polyurethane foam, so as not to spoil the equipment and get high-quality thermal insulation.
Criteria for the selection of polyurethane foam and equipment for its spraying
When choosing the type of polyurethane foam for insulation of certain structures and walls, the following recommendations should be taken into account:
- It is not recommended to insulate walls by spraying polyurethane foam from the inside. So the dew point shifts, and the surface will freeze. It is also fraught with moisture condensation if rigid material is used. The walls will be damp all year round.
- If it is impossible to use other materials, then the walls should be insulated from the inside of the room with semi-rigid polyurethane foam. The optimal layer is 25-30 millimeters.
- For outdoor use, take rigid polyurethane foam. There is no need for a vapor barrier. The walls will be reliably protected from the destructive effects of freeze-thaw cycles.
- For roof insulation, soft foam and liquid polyurethane foam are intended.
- Tile material with high rigidity and density is excellent for thermal insulation of the foundation. The size of the polyurethane foam can be different. Usually it is 500x500 millimeters.
Before starting work on self-application of polyurethane foam, you should choose the right equipment. It is called a foam generator. Its main task is to mix the components in the right proportion. The equipment can be divided into low and high pressure units. For domestic needs, a low pressure foam generator is suitable.
Many models provide optimal temperature conditions. If you plan to spray during the cold season, then a heated installation is what you need.
Price and manufacturers of polyurethane foam
Polyurethane foam is a product of mixing and reaction of two substances: polyol (component A) and polyisocyinate (component B). The latter is not produced in Russia. It is supplied from abroad.
It is worth noting such manufacturers of polyisocyinate: Bayer, Elastogran (Germany), Huntsman (Holland), Dow Chemical (USA). All these manufacturers of polyurethane foam (component B) produce material of approximately the same quality and cost - from 165 rubles per kilogram.
Domestic companies produce polyol. The following manufacturers can be distinguished: Dow-Izolan, Khimtrast, Polyol Plant, Urethane and others. The price of polyurethane (component A) is about 250 rubles per kilogram.
Russian manufacturers also produce decent quality tiled polyurethane foam. Its price starts at 500 rubles per square meter.
Brief instructions for the installation of polyurethane foam
The technology for applying polyurethane foam does not differ depending on the surfaces to be treated. External, internal walls, the facade are insulated according to the same scheme, while a crate is preliminarily created from wooden bars with a step of about 30 centimeters. There is no need to install additional battens for thermal insulation of the foundation and roof. We carry out the installation of polyurethane foam as follows:
- We open the taps on the cylinders with the components and press the trigger of the pistol. Foam starts to flow from the nozzles.
- We apply it starting from the bottom of the wall. If we are talking about the thermal insulation of the foundation, then from the far corner. The same goes for roof insulation.
- The gun must be kept no closer than 20-25 centimeters from the surface.
- Move the stream smoothly and apply evenly.
- If you need to move to a new place, then turn off the gun. Before starting work again, it is necessary to change the nozzle.
- If you apply two layers of polyurethane foam, then the second should be sprayed only after the first has completely polymerized. The average thickness of polyurethane foam is usually 25-50 millimeters.
- We make sure that the layer of insulation does not protrude beyond the crate.
- Cut the frozen polyurethane foam, if necessary, with a construction knife flush with the crate.
After the insulation has hardened, the surface of the walls must be reinforced with a special mesh and corners. After that, you can begin to carry out finishing work - plastering, painting, installing siding and so on. Watch a video review of polyurethane foam:
Polyurethane foam surpasses all other heat insulators in a number of properties. In particular, it has very low thermal conductivity, high adhesion and hydrophobicity. It is lightweight and environmentally friendly. But to work with it, you need special equipment. And if you do not have the opportunity to rent it, then it is more advisable to hire a team of professionals, since it is impractical to buy expensive equipment.
