The wall are made in the masonry structure, and predominantly the buildings have a simple material structure. The Prussian wall is a skeletal structure made of wood, filled with various building materials, mostly partly ceramic brick, mixed with straw or other reed. This gives a peculiar architecture and the original look of the buildings, creating a lot of problems while the priorities in building are energy efficiency. The article presents the thermal-moisture wall analysis of the Prussian wall with the design insulation on the inside, in the living room. Two documentation materials were used: rock wool and EPS. The behavior of the wall was compared in terms of the water content of each material after one year of operation