A cavity wall consists of two separate walls (brick structures). In order to comply with the energy saving requirements set out in the current regulation, the external walls must have adequate thermal insulation.
In new buildings, if the more efficient solution of external thermal insulation is not used, this is achieved by placing the thermal insulation in the cavity.
Water absorption resistance is the most important factor in choosing a thermal insulation material used in double cavity wall. This is because moisture enters the cavity. Thus, if the material gets wet and does not have high resistance to moisture, it automatically loses part of its thermal insulation property, even if it dries later.
Ravatherm XPS X Wall BL and Ravatherm XPS Wall BL extruded polystyrene boards are the ideal materials for thermal insulation of cavity walls, offering extremely high resistance to moisture.