Thermal insulation of polyurethane foam in questions and answers

On the eve of the winter it is becoming increasingly relevant question of warming the house. In the construction market there are many modern heatersThat can transform your home into energy efficient home. Along with conventional materials, such as rock wool and extruded polystyrene, all of great interest from the developer causes such a method as sputtering insulation foam. And this is not surprising, because all of us want to live in a warm, which means a comfortable home.

So how do you properly insulate the house with the help of foam? And what features have this material? To answer these questions, we will help users forumhouse.ru!

Foam or polyurethane foam

You thought that in our modern and fast life, every day we are faced with a variety of polyurethane foams? Scope of this product is high-tech is very extensive.

For example, in the manufacture of furniture, penopoliuretanispolzuetsya as a cushioning material. In the automotive industry it is filled with chairs and fight with the noise in the cabin.

Polyurethane foam, belongs to the group of gas-filled plastics, manufactured on the basis of polyurethanes. These plastics 85-90% consist of an inert gas phase. And the type of feedstock will determine whether rigid or flexible polyurethane foam.

Since we are primarily interested in the use of this material as a heater, it is necessary to understand its main features. According to its users our forum Maxim Brovina (forum name Maxbrovin) Foam for insulation can be divided into 4 groups:

Light, open-cell polyurethane foams. Density - 9.11 kg / m3. Thermal conductivity coefficient - 0.04. The water vapor permeability of the polyurethane foam is comparable to the mineral wool.

Open-cell polyurethane foam should be considered as a heater only in cases where there is deposition on the surface with high adhesion.

Maxbrovin (Member FORUMHOUSE):

–According to its properties open-cell polyurethane foam is similar to the mineral wool, and is more expensive. But shows good performance soundproofing.

closed cell foam. Density - 28-32 kg / m3. Coefficient of thermal conductivity - 0,02-0,028. Permeability 0.05.

closed cell foam. Density - 40-60-80 kg / m3. Coefficient of thermal conductivity - 0.03-0.04. Water vapor permeability - 0.04-0.05.

It is used for insulation of floors and roofs operated under the screed with heavy loads. In the case of conventional insulation of walls and roofs use of this material is unreasonably, t. K. The thermal conductivity and the price of it is higher than the closed cell polyurethane foam with a density of 28-32 kg / m3.

Foam for filling in the cavity. According to its properties, this is similar to closed cell polyurethane foam, but it is much slower foams and hardens only after the full expansion.

The advantages of closed cell polyurethane foam with a density of 28-32 kg / m3 and of sputtered high-pressure apparatus includes:

• The lowest thermal conductivity among heaters - 0.02. In the air ratio is 0.022.

Maxbrovin:

- This is achieved through the content in the cells of carbon dioxide and other gases. After the warranty period of 25 years, gas is gradually replaced by air, and the thermal conductivity is increased to 10%. The other properties are not changed.

• Seamless method of laying of the sprayed polyurethane foam. Due to this, it creates a sealed vapor-windproof to warm cocoon.
• High adhesion to all building materials (except polyethylene).
• Low vapor permeability and water absorption. Ability to use in extreme conditions of swimming pools and other buildings with high humidity, the structure insulate underground without any additional protection, and so on. D.
• High speed of work on warming.

Among the disadvantages of this heater can be identified:

• price insulation almost two times higher than when using mineral wool;
• complex deposition technique requires the use of expensive equipment, as well as placing increased demands on the performers skills;
• This technology is practically not used in self-warming.

polyurethane coating technology

For foam corresponding to the specifications must be met by many factors. Of fundamental importance is the "ideal" mixing of the components in the proportions specified by the manufacturer, with necessary time to do it in less than one second. For this purpose airless spraying each component separately with a pressure not less than 120 atmospheres.

Maxbrovin:

- Due to the high pressure sputtering is performed in a very finely dispersed phase was substantially fog which is mixed in the vortex chamber and then enters the gun is sprayed on the surface.

The second necessary condition - the thermal component mode. To injectors components have come to a temperature of about + 45C. However, depending on the temperature and humidity of the environment (such as air or surface) temperature components vary in a range of 30 degrees, with each of the components (component temperature never equal).

For high-quality spraying is necessary to keep the following conditions:

• ambient temperature - not lower than + 10C, the surface is completely dry, the absence of any oil on the surface;
• limiting conditions for deposition: -5C and high humidity.

Many users have a question: "And how is the deposition?"

Maxbrovin:

- Come a large machine, which is a high pressure compressor and barrels of feedstock. If the house is only 220, it uses a small device with a short hose.

In this case the operation is slower than when using the three-phase electrical network to 15kW, since in this case the house only long dragged hoses and installation itself is on the street.

If there is no electricity, use a diesel generator to power the compressor.

All windows, doors, trim, and so on. D. - all that can be soiled, it is necessary to very carefully cover films and prokleivat masking tape.

Solvent for the solidified foam does not exist. Because adhesion in a large Styrofoam, then tear off the solidified material can be only mechanically. During sputtering present not strong, but unpleasant odor. After airing it is removed without a trace. "Embarked" PPU does not smell at all.

Maxbrovin:

- Because Foam - a material absolutely inert, then, accordingly, it does not emit into the air or volatiles, no dust.

Expanded polystyrene is allowed to store food. Flammability - T2-T3 (self-extinguishing, not support combustion). T. e. PPU itself will not burn, but if there is an open flame source, the polystyrene is lit with the release of smoke.

PPU questions and answers

Often, our users have many questions relating to the proper application of the foam. Let us examine the most private ones.

STASNN(Member FORUMHOUSE):

- foam - insulation is a good way, but I am concerned about the question: what will happen to the tree, located within the "coat" of foam? I mean carrying frame rack. They are installed with a moisture content of 12-15%, or even more, and then find themselves in vapor tight envelope. There is no entry or exit moisture.

Matilda(Member FORUMHOUSE):

- According to various sources, the water vapor permeability of wood is water vapor permeability foam - it's somewhere 0.05-0.06. So that problems can not be.

Maxbrovin:

- There is one interesting point. It turns out that the value of the tree is brought across the fibers, and along - the value of water vapor permeability of 0.3-0.4. From my own experience I can say that the problems with the wooden structures in the houses after spraying polyurethane foam not arises.

Open-cell polyurethane foam is sprayed on the inside, the roof is prohibited in our climate! Although, as heat insulation, lightweight foam, works as Lambda 0.036 he is better than that of mineral wool. But, because of their vapor permeability, such polystyrene foam requires a vapor barrier and air quality, leading to an unjustified increase in the cost of the work.

Another issue of concern to many developers: is it possible to independently open cell sprayed polyurethane foam, for example, from a container with foam?

Proul23(Member FORUMHOUSE):

- With closed-cell polyurethane foam with all clear - equipment for spraying expensive and buying it to insulate their houses - not very cost-effective. But I had this idea: if and save yourself assembly foam sprayed from a simple balloon?

GeoOs(Member FORUMHOUSE):

- Polyurethane foam spraying with this method gives a mixed cell, ie.. about 50 to 50 open and closed cells. Moreover, the foam structure is highly uneven, with the stronger, the more you make a mistake with the required humidity (surface pre-moistened, as the interlayer surface) and is easy to make a mistake (many factors: temperature, original moisture content - like surface and air).

As for the mixed cell, then it has no advantages. It absorbs water well and gives bad; strength in her lower, noise - small.

FaSeG(Member FORUMHOUSE):

- Last year, we experimented by spraying foam from cans. Flow cartridge 1 turns = 1 sq. m. The layer thickness of 3 cm. Sprayed neighbor home from lightweight aggregate concrete blocks. When cut structure non-uniform, cell - up to 3 mm. According to the data of thermal conductivity is not present, but a neighbor all the same continued to freeze in the winter, as well as to the insulation foam.

And how are things with foam resistant to UV?

amir_t(Member FORUMHOUSE):

- With regard to the deficiencies foam, I would add a strong sensitivity to sunlight polystyrene.

But it is not so simple.

Maxbrovin:

- sensitivity to UV light from polystyrene, and the truth is strong. And it is expressed in darkening initially nearly white material to dark brown. For the sake of the experiment, I tested a sample of foam, sputtered 7 years ago, on the south wall of the garage. So, during this time he collapsed layer only 1-1.5 mm, and then the white styrofoam and sturdy, as well as just sputtered.

Destroyed polystyrene layer protects from ultraviolet radiation.

Also, foam is sprayed inside the already laid out the brickwork, but there are some features and secrets.

Maxbrovin:

- There are special systems for filling in the cavity. Here, the main difference - the time polirimizatsii PPU. Regular foam to foam for 2-3 seconds, filler - is several times longer. A hardens in a few minutes.

Due to it, the foam fills the volume better. When this does not happen "distension" design. Solidification begins only after the full expansion. The most frequent application - is to fill the air gap between the foam blocks and facing bricks.

Maxbrovin:

- For 20-30 cm foam block foam thickness of 5-7 cm - this is a good solution. The problem of dew point at the boundary block and foam occurs. The dew point is shifted foam layer, which vapor tight, hence, the condensation can not be.

It is impossible to fill foam if the foam block thickness - 40 cm, and the air gap - only 3 cm. In this case, the foam block will dampen, with all the negative consequences.

Maxbrovin:

- Filling takes place through the holes drilled in the masonry joints 12 mm drill every two bricks and four horizontal - vertical. The process is complicated by the fact that when casting has to continuously balance the insufficient amount of foam (Accordingly, the remaining air cavities) and an excess of polystyrene, which climbs from the openings and contaminate the facade insoluble foam.

Due to the much smaller production volumes, the cost of the foam filler at 30% above sprayed.

At warming the house inside the main thing - it's monolith zapenit all the walls and ceilings, bordering the street, and accept the inevitable freezing of construction. Such spraying is widely used for insulation of loggias, attached to the apartment.

In the presence of cracks or holes guaranteed serious problems with the release of steam through this single point.

Wall insulation inside permissible low R (the thermal resistance coefficient) of the wall. If the wall is very warm, the warm house using foam should be only from the outside. If warm outside, the wall becomes warmer because R and wall insulation are summarized. If from the inside, the outside wall starts to freeze, and the contribution to the overall thermal resistance will not make.

Hot discussion topics: "polyurethane foam" is conducted in this the topic of our forum. Learn about all the features of open-cell polyurethane foam users forumhouse.ru can here. Vivid and detailed account of our new posts about how her skeleton lumber house is insulated using polyurethane foam, available at this link.

And this video It gives details about all the features of home insulation by spraying polyurethane foam.

Discuss the article and read other materials devoted to country life you can on the websiteFORUMHOUSE.

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