This paper presents the analysis of 801 damage occurrences in building roofs, which were classified qualitatively as well as quantitatively. They have been correlated according to the type of roof in question, and the most frequent situations have been determined. The prevalence of the causes behind these problems is indicated, and a technical discussion concerning each one is presented. These results provide property developers, designers and construction managers with information on the critical points of roofs, as a way to minimize defects in their building sites. This damage analysis provides a series of lessons learnt in order to improve the quality of construction in general.