This includes the application of polyurethane foam by air-spraying on the attic floor surface or internal side of the roof frame structures on a pitched roof.

The technology of works for insulating horizontal surfaces by this method is as follows:

• removal of trash and damaged hydro insulation from the roof;
• jointless spraying with polyurethane foam. The density of the polyurethane foam should be about 50-60 kg/m³. Spraying is made in several layers, thickness of the first layer must be 2-5 mm, and the second and next layers − 10-25 mm each. Each layer needs to stiffen after application. This technology of polyurethane foam application will ensure the proper density of the heat insulation layer;
• for polyurethane foam protection from ultraviolet radiation and ensuring additional hydro insulation, a protective spraying with liquid resin or urea resin is applied above the insulation layer;
• to be able to walk on the insulated section, and to protect it from a mechanical load, a solid board flooring or board walking paths is necessary (especially in the attic).

If the insulation of a pitched roof frame structure is done with the use of this technology, more elastic grades of the foam should be used. Also, the density of the polyurethane foam must be about 20-30 kg/m³. In this case, to protect the polyurethane foam from inside the attic, gypsum board liners or oriented strand boards etc. should be used. Among other things, this allows indoor painting and decoration to proceed right away if there are plans to use the attic premises after heat insulation.

The average cost of a polyurethane foam sprayed layer is UAH 1,400 /m².