The double wall consists of two prefabricated concrete skins filled with concrete. Two parallel reinforced concrete skins with a minimum thickness of 5 cm are joined together with lattice girders. Double walls are prefabricated offsite in the factory, delivered to the construction site, installed and finally the cavity is poured to form a monolithic wall. The advantage of the double wall is the elimination of formwork on site - with a considerable shortening of construction time, and the two fair faces.