Insulating exterior walls, in particular, which has been done for over 40 years, is a proven method for
thermal protection, economy, fire safety, durability, stability, and aesthetics.
This technology is now referred to as “ETICS” (Exterior Thermal Insulation Composite System). Foamed polystyrene boards are glued to the exterior wall (sometimes using dowels in addition to adhesives). Next, perlinker and adhesive are applied to the board. Once the adhesive with embedded mesh has dried, the next step is to prime the board and apply a thin coat of silicon plaster or similar in a color of your choice.
What should be considered when choosing wall insulation?
The most important factor is the insulation properties. The parameter to check is lambda, or thermal conductivity. For example, graphite polystyrene, which has gained popularity in recent years, has a maximum thermal conductivity (lambda) of 0.013 W/mK. The lower the lambda value, the better the insulation properties of the polystyrene foam board and the better the thermal protection of the building, even if the board thickness is small. For extruded polystyrene, tensile strength (TR) is also important. The minimum level is 80 kPa. Materials with lower tensile strength (TR) have the potential to break at lower forces and, consequently, may fall off the wall.
Which adhesive should I choose for bonding expanded polystyrene boards?
Polystyrene itself does not “stick” to the surface of the wall, so a properly formulated mixed adhesive is used to secure the polystyrene foam board for permanent insulation. The adhesive is part of the insulation system and only adhesives included in a complete system may be used. While fixing the insulation to the exterior wall surface is one of the most important tasks, a very important second step in the insulation process using adhesives is to reinforce the facade with a parline embedded in a layer of all-purpose adhesive. This contains polypropylene fibers dispersed throughout and reinforces the entire insulation system. The all-purpose adhesive does two things: it glues the expanded polystyrene board to the surface of the insulated wall and it creates a fiberglass-reinforced layer.