Cavity walls consist of two faces with an empty space in between to apply thermal insulation boards or panels. This building technique is widely used across Italy because it ensures a high degree of thermal comfort by keeping the interior walls warm. Walls are usually either curtain walls or load-bearing walls: in the latter case, the outer face often has an at-sight masonry finish (bricks) and protects the load-bearing wall against bad weather while preserving the inner thermal insulation, as the latter is no longer accessible. The advantage of double walls is that the load-bearing wall on the inside accumulates and preserves heat at length. Wall performance is further improved by creating ventilated air spaces, namely an air barrier between the outer face and inner face on which the insulation boards are applied: air circulation maintains a low concentration of water vapor and provides a further degree of protection for the insulation over time. Air circulation is ensured by means of vents in the outer face and the use of spacers between the outer face and the insulation layer. POLIISO^®  PLUS is the best solution for this type of application, since it ensures long-lasting performance, it is a closed-cell product that prevent water from penetrating through the foam and causing the deterioration of the panel's thermal performance (which happens, instead, with open-cell or fiber insulation) and has a μ value = ∞, namely it is a total vapor barrier. Thanks to the aluminum foil layer, the panel affords one of the best thermal conductivity λ available on the market ( λ_D = 0,022 W/mK),  thus allowing you to save on the applied thickness. POLIISO^®  PLUS also comes in 1200 x 3000-mm panels, thus making laying much faster, since all you need is a single panel to cover the entire height of the wall.  The panels are fit together so that there are no interruptions in the material without any risk of thermal bridging. In case of buildings with a load-bearing structure and outer curtain walls, thermal bridging can be easily solved by passing the thermal insulating layer outside the pillars.