The cavity wall consists of three layers. Each takes on an important function and together they combine the robustness of the solid exterior wall with triple thermal protection:
- The back wall is the load-bearing wall.
- The insulation layer forms the buffer zone between the outside and inside climate. It can be up to 20 cm thick. A thicker insulation layer does not increase the energy-saving effect any further.
- The facing brick made of frost-resistant brick or clinker forms the outer façade and permanently protects the insulation layer and the rear wall from all weather and environmental influences. It also has a temperature-balancing effect, i.e. it keeps out the heat in summer and cools down more slowly in winter. A cavity wall consisting of facing bricks (11.5 cm), an insulation layer (10 cm) and a back wall (15 cm) is less than 40 cm thick: quality insulation with slender walls is possible and even the passive house standard can be achieved.