The study concentrated on the extent of moisture and mould damage in different structures in 25 public buildings in Finland. Users of all the buildings had health symptoms suspected to be the result of moisture and mould damage, which is why moisture performance assessments had been performed. The assessment reports on each building were available as research material. The reports indicated that the examined buildings suffered from multiple moisture and mould problems in several different structures. On average, however, a relatively small proportion of the total number of structures had suffered damage. On the basis of the research material, damage was most extensive in walls in soil contact (16.3%) and base floor structures (12.5%). The lowest damage rates were found in partition walls (2.4%), external walls (2.6%) and intermediate floors (2.5%). The results of the study underline the importance of thorough moisture performance assessments to ensure that all point-sized moisture and mould damage is detected.