The use of liquid polyurethane foam as an insulating coating for the foundation, the features of such thermal insulation, its advantages and disadvantages, surface preparation and material spraying technology. The disadvantages of polyurethane foam insulation are not significant: the material is not UV resistant and is sensitive to weather conditions during installation. The need to use special expensive equipment for applying insulation can also be attributed to its disadvantages. However, the equipment can be rented for the duration of the work. This possibility and the low price of the material outweigh this disadvantage.
Preparatory work before installing polyurethane foam
Before applying the polyurethane foam, a number of preparatory work must be done. This will help increase the efficiency of the insulation and its service life.
The underground and basement part of the foundation is subject to insulation. In order for a place for convenient work to appear, a trench with a width of 0.7-1 m should be dug around the building around its perimeter. Its inner wall will serve as the outer surface of the buried part of the house, freed from soil. The depth of the trench should correspond to the level of the base of the foundation.
Then the surface to be insulated must be cleaned of the remnants of dirt, plants and fungal formations, check the walls for the absence or presence of chips and cracks. The identified shortcomings are recommended to be eliminated.
After cleaning and minor repairs, the foundation must be well dried. If it's sunny outside, this process will take 2-3 days. In other cases, special equipment will be required. It is important to know that PU foam has poor adhesion to wet surfaces. An air layer that can form when they come into contact with the insulation will become a condensate accumulator, gradually destroying the foundation.
The above-ground part of the supporting structure must be equipped with a frame before insulation, on which it will subsequently be possible to fix the plinth lining. The frame can be made from galvanized metal profiles.
Despite the fact that polyurethane foam well protects the base from moisture, before insulating the outside of the foundation of the house with polyurethane foam, it is recommended to treat it with a protective compound to increase adhesion, remove microorganisms, and then with bitumen mastic as additional waterproofing.
After completing the preparation of the foundation for insulation, you can start applying the polyurethane foam coating. To work with caustic foam, it is necessary to stock up on overalls, a respirator and goggles, since contact of liquid material in the eyes, on the skin or in the respiratory tract can harm health.
The technology of applying polyurethane foam to the foundation
For spraying polyurethane foam on the foundation, a high pressure unit is used. Its plunger pumps are driven by an electric motor and dispense liquid components to create the required foam density. Mixing of components takes place in a special chamber of the installation. The finished composition enters the surface of the foundation through a spray gun, the intensity of the foam supply is regulated by the remote control.
With the help of the installation for spraying insulation, it is possible for two people per shift to perform insulation on an area of up to 1000 m2… The device has an enviable productivity - more than 350 liters per minute. It is provided by a high pressure of 260 atm generated by the equipment pumps.
When starting work, you need to make sure that the equipment is in good working order and the current in the mains corresponds to the value of 220 V. For the sample, you can perform a test spraying on any part of the foundation. This will make it possible to make sure not only the operability of the installation, but also the quality of the foam relative to its homogeneity composition.
The application of the insulation with a spray gun on the walls of the foundation must be carried out so that the thickness of the foam layer in one pass is within 5-10 mm. In this case, the consumption of polyurethane foam is 0.5-1 kg / m2… It can change depending on the surface topography, weather conditions, etc.
In order for the adhesion of the coating to the substrate to be acceptable, the surface of the foundation before spraying must be dry, free from traces of oil, dirt, paint and rust. Due to the fact that foam components tend to slightly delaminate over time, an important aspect in terms of the safety of this material is to ensure optimal conditions for this.
They can be observed by periodically rolling the barrels from the polyurethane foam. At the same time, their contents will be homogenized, becoming suitable for work. To exclude poor quality of thermal insulation, you should adhere to the proportions of the components of the material specified in its data sheet by the manufacturer.
Insulation of the PPU foundation is carried out in layers, thus achieving high adhesion of the material at the joints. General recommendations for achieving an effective result of thermal insulation of the foundation with polyurethane foam are as follows:
- The surfaces to be treated must be clean and dry.
- If the wind speed is more than 5 km / h, it is better to refrain from carrying out work.
- When insulating the foundation from the outside, the temperature of its surface should be higher than - + 10 ° С, of the components of the mixture - about + 18-25 ° С, atmospheric precipitation is undesirable.
- The thickness of the PPU layer, sprayed in one pass, should be no more than 10 mm.
The service life of the polyurethane foam coating can be significantly increased. For this, after polymerization of all layers of foam and backfilling of the trench, a concrete blind area is made around the perimeter of the building. This work can be performed no earlier than three days after the completion of the thermal insulation of the foundation walls.
How to insulate the foundation with polyurethane foam - watch the video:
Spraying insulation on building structures is a high-tech and new solution. When expanded, liquid polyurethane foam increases its volume 40 times. Hard foam has closed pores and is difficult to damage. Knowing how to insulate the foundation with polyurethane foam, for these reasons, it is sometimes possible to refuse thermal insulation with traditional foam.
