**2. Materials and Methods**

#### *2.1. Adhesive*

A single-component polyurethane adhesive, intended for ETICS, a standard for fixing EPS to masonry and concrete substrates, was used for the study. The adhesive was manufactured in industrial conditions as a commercial product. Polyether polyol was used. Organic amine catalyst served as a catalyser to promote blowing reaction. Silicone surfactants were used to stabilise the foam. Polymeric diphenylmethane diisocyanate (PMDI) was used to cure the foam. The components were placed in a standard pressurised container. As a chemical blowing agent, carbon dioxide was generated via the reaction of water included in the substrate, thermal insulation material and the environment with isocyanate groups. The adhesive was applied using a dedicated gun. When sprayed, the adhesive was in the form of a low-pressure foam. The foam adhesive working properties, determined according to [23], are shown in Table 2.

**Table 2.** Polyurethane adhesive working properties.


<sup>1</sup> Declared by the manufacturer, <sup>2</sup> temperature of the substrate, insulation material and environment.
