Diagnostics and mitigation of excessive moisture effects are some of the most frequent problems in historical buildings. In this article, an attempt was made to measure the moisture content of construction elements in the historical tenement house in Gubin. It is the largest town in the Krosno Poviat, in the area of the Lubuskie Voivodeship. The town suffered from military actions during World War II whereby approximately 90% of its urban development was destroyed. The tenement house at 14A, Śląska Street is one of the more well-preserved buildings, made in the classicist style with characteristic historical features. The whole history of the building is unknown but there are freemasonry symbols on the elevation, and probably the Military Police had its headquarters there after 1945.