The article presents the destructive influence of external factors on building partitions in selected historic buildings made from made full-bodied solid ceramic bricks. The external factors are an additional element that adversely affects the maintaining of historic buildings in a good technical condition, and they are complementary to a number of harmful factors that destructively act upon on such buildings. In order to estimate the range of damage in historic buildings, selected buildings that have been exposed to external factors for a long time in the Podlaskie and Warmińsko-Mazurskie Voivodships were analysed.