The main nuances of thermal insulation with polyurethane foam of an attic, about the advantages and disadvantages, how to prepare a room for insulation, how to install the material, finishing the surface. Insulating an attic with polyurethane foam is one of the best ways to protect a building of any type and purpose from inevitable heat loss. This modern material is used in construction wherever thermal insulation is required: on the floor, ceiling, walls.
Features of the use of polyurethane foam
Polyurethane is one of the most popular insulation materials due to such characteristics as low thermal conductivity and low water absorption. Has a structure similar to a frozen film. Polyurethane foam is divided into groups: soft, the so-called "foam rubber"; rigid - made by molding; sprayed - supplied in liquid form and applied by spraying. The latter is the most common in construction, dries quickly, which allows you to apply several layers to the surface to be treated in a short period of time.
Modern technology of attic or attic insulation with polyurethane foam compares favorably with the use of bulk and fibrous materials. This allows you to save the room from excessive moisture and condensation accumulation in the under-roof space, due to the fact that the insulation does not allow water vapor to pass through.
It is believed that to reduce heat loss in the house, it is enough to insulate only the floor in the attic. But an even greater effect can be achieved if the roofing surface is also protected. When insulating the roof with polyurethane foam, the spraying method is most often used, which saves time up to 80%, and money - up to 50% compared to other heaters. The same operation must be performed in the case of using the attic as a living space. The attic must meet all the requirements and, in addition to insulation, have hydro and noise insulation, fire safety standards must be observed.
Scope of use of polyurethane foam:
- It is used for insulation of external and internal walls, roofs, in construction and in the implementation of major repairs of residential buildings and various industrial premises.
- It is used for thermal insulation of pipelines, since the applied material allows you to create a waterproofing coating of the pipe, eliminates the need to use additional protective agents, paint can be applied on its surface as protection from sunlight.
- It is used for thermal insulation of various tanks and reservoirs, including in nuclear and thermal power engineering.
- Serves as a material for the treatment of refrigerated chambers and vans.
Advantages and disadvantages of polyurethane foam
Insulation polyurethane foam does not require special surface preparation, as it perfectly binds to all materials (wood, metal, concrete), forming a shell that is poorly permeable to heat and vapors. It also allows you to make the structure stiffer, while not significantly increasing the weight, which makes it possible to use it in frame structures. Among the main advantages, we highlight the following qualities:
- Moderate coefficient of thermal conductivity. The advantages of the material are obvious when compared with other insulation materials. For example, equal thermal conductivity is provided by mineral wool with a thickness of 2.5 times, and expanded clay - 8 times.
- High adhesive characteristics.
- Provides excellent acoustic insulation.
- Lack of "cold bridges".
- The ability to apply a heat insulator to structures of any size and configuration or angle of inclination, incl. on the ceiling surface, eliminate all irregularities, cracks, due to the high permeability of the applied material under pressure.
- Durability of coatings: polyurethane foam is not exposed to the environment, does not lend itself to temperature fluctuations, does not crack. If operating technology is observed, it can serve for 25 years or more.
- Environmentally friendly material, recommended for use in food industry cold rooms.
- It is sprayed on a wide range of materials: silicate or ordinary bricks, concrete, wood, glass, painted surfaces.
- It is quickly applied to the insulated surface, and also has the ability to quickly harden.
- Polyurethane foam is biologically resistant to microorganisms, fungi, and various rodents.
- Non-flammable, does not spread combustion, belongs to the class of hard-to-burn and hard-to-ignite materials.
- Has a low coefficient of moisture absorption, does not require an additional vapor barrier layer.
- Lightweight material, does not create additional loads on the structure.
- Simplifies do-it-yourself installation, does not require additional fasteners.
- Withstands temperatures from -50 to +120 degrees, resistant to hot weather and low ambient temperatures.
- It makes it possible to adjust the density and strength of the future insulator directly during the execution of work due to the use of raw materials of appropriate quality.
Along with the indicated advantages, polyurethane foam has some disadvantages that are important to know for more successful use in construction and repair:
- High production cost and, accordingly, the cost of the material produced.
- It is difficult to apply PU foam in high winds when working outdoors.
- When applied to the facades of high-rise buildings, the component spreads quite large (it flies into cars, windows standing next to it).
- It is destroyed by ultraviolet radiation, therefore, if the material is applied outside the building, it must be covered with something, for example, paint or special mastic.
- Work on the application of polyurethane foam can be carried out at a temperature not lower than +10 degrees, since it expands poorly and, accordingly, will be poorly sprayed.
- The material is not flammable, but it will smolder for a long time until it cools down.
Attic insulation technology with polyurethane foam
The process of applying polyurethane foam to the attic surface is not as difficult as it seems at first glance. To do this, you need to purchase or rent an apparatus for spraying a heat insulator, as well as buy the material itself in the required quantity. Attic insulation works are carried out both during the construction of buildings and at any time of its operation, if such a need arises.
The most effective temperature regime for applying the material is + 20 + 30 degrees, at a lower temperature the insulation foams poorly, which means that the consumption of material increases, the work is partly complicated and the quality deteriorates.
We free the attic surface that needs insulation from dirt, debris and other contaminants, and clean it, if necessary, with a sharp spatula. This also applies to surfaces made of any material, if, for example, the attic is insulated. All irregularities on the surface, without exception, require removal. If the spatula becomes dull, it is constantly undermined. In order to seal up all the existing joints, you need to remove the old materials with which they were sealed, and those remnants that are poorly removed can be removed using a perforator. Old lime can be easily removed with a spatula after preliminary wetting with water using a brush or a spray bottle. Water-based paint can also be removed with a spatula, after soaking it with iodine diluted in water in the proportion: 1 bottle of iodine per bucket of water. Water-based paints are removed using special solutions.
If there are foci of fungus on the ceiling, it must be removed with an aqueous solution of copper sulfate (5 g per 1 liter of water). After cleaning the attic, be sure to let it dry.
The main tools used to insulate almost any surface with polyurethane foam are: a foam generator for mixing the material, a high pressure apparatus, safety glasses, a respirator, a protective suit, a sharp spatula, a working bucket, a perforator, a brush, a spray gun, a hammer, a screwdriver, a trowel, a level, sharp knife-cutter, chisel, emery cloth or sandpaper, dry rags.
Materials used for applying polyurethane foam: insulation, primer, dry mix of plaster, water, putty.
When applying polyurethane foam, it is recommended to use the devices of the world famous American company GRACO, namely the REACTOR installation. The model range is quite wide, from the low-level device REACTOR E-10, the models of medium productivity REACTOR E-30 and up to the units with the hydraulic drive REACTOR H-XP3, REACTER H-50. For small volumes, up to 100 m2 spraying per day, use the REACTOR E-10 installation.
Installation instructions for polyurethane foam in the attic
In order to protect your health, all work on the preparation and application of polyurethane foam must be carried out in protective clothing, glasses and gloves.
A special foam generator foams the components (polyisocyanate with polyol): foaming occurs due to carbon dioxide, the prepared mixture is heated to high temperatures, and then the component is supplied under pressure to the gun, with which it is sprayed onto the prepared surface. In this case, the material enters all the cracks and covers all protruding structures.
The thickness of the application of the thermal insulator is approximately 10 cm. Each new applied layer is no more than 2 cm. After the last layer has been sprayed, the application of the material must be stopped and allowed to harden well. The insulating material gradually hardens within 10-12 seconds.
Polyurethane foam is applied to the surface to be insulated as a liquid mixture, but it can also be used as a fill. The material is poured into molds in advance, and then the finished blocks are attached to the insulated surface using dowels.
After drying, the excess material is carefully trimmed with a knife or other sharp instrument. At the end of the application of polyurethane foam to the surface and its drying, you can plaster the insulated attic.
Finishing the attic
We proceed to finishing the attic. These works will help to create additional protection for the heat insulator from moisture penetration and provide the aesthetic appearance of the room.
For the decoration of attics, it is proposed to apply the following options:
- Plastering followed by whitewashing;
- Pasting the surface with wallpaper;
- Installation of suspended ceilings (plasterboard, panel or rack).
The specific finishing option is used depending on the purpose of this room. If it was only important to insulate the room, it would be right to choose a simpler and more economical finish. If, for example, it is an attic and is used for recreation or housing, the decoration can be made more aesthetic.
Let's consider in more detail the option of plastering the attic space. In order for the plaster to hold firmly, we use a special mesh for exterior or facade work, with a density of 140-160 g / m2.
Recommendations for applying plaster to insulation:
- We cut the mesh into pieces of 1 meter, apply a universal mass to the roof, apply the mesh and use a spatula to try to "drown" it into the adhesive mixture.
- After drying, the surface with the glued mesh must be carefully sanded with an emery cloth.
- Apply the plaster solution with a spatula or trowel, then level the material with a metal spatula and let it dry.
- After drying, we smooth the surface again with an emery cloth. Grouting should be carried out no earlier than 1 day and no later than 4 days, since exceeding the term will require great efforts.
- Apply a coat of primer and let it dry.
- After that, you can start decorating the attic surface.
Using the listed recommendations and instructions, you can independently insulate the attic without using the services of specialists.
How to insulate an attic with polyurethane foam - look at the video:
Insulation of an attic with polyurethane foam is an affordable and convenient construction technology. Work on the thermal insulation of the attic is carried out quickly enough, allows you to save money on heating and repairing the building, and with careful maintenance, the insulated attic can be operated for more than a dozen years.