The article presents an analysis of the technical condition and the causes of damages of the plasterboards (with increased fire resistance) casing of the roof in a single-family building with a wooden frame structure with panel roof. The roof was covered with a metal sheet on a spacer mat with mineral wool insulation, covered with a roof foil and a vapor barrier. During the operation of the building, numerous cracks began to appear at the junction of the roof covering and walls, reaching a width of up to 1.5 cm. Based on the conducted analyzes, it was found that the cause of the damage was fluctuations in the humidity of wooden roof elements, resulting from the lack of proper ventilation of the roof layers.