The negative impacts of heavy rain are increasing due to both changes in precipitation patterns and the rising vulnerability of buildings at risk. The negative consequences of heavy rain depend on the physical vulnerability of buildings, i.e. on the potential of exposed materials and structures to be harmed and to suffer damage. Heavy rain events are often highly localised. Therefore, the estimations of their probability and magnitude are challenging.

Heavy rain affects buildings both directly and indirectly. First, engineering surveys have proven the broad variety and high physical vulnerability of building constructions and their connections that are directly affected by invading water during heavy rainfall events. Following the studies, heavy rain is identified as the most important moisture source that affects e.g. the hygrothermal performance and durability of building façades or leads to interior damage due to water penetration. The paper explores the most frequently affected construction elements as well as the most important damage mechanisms.

Second, outside mountainous areas heavy rainfall events may lead to pluvial flooding depending on the local topography and the capacities of the urban drainage infrastructure. Pluvial floods are predominantly characterised by low water levels and affect the basements and ground floors of buildings. The paper elucidates, how to quantify pluvial flood risks on housing on small spatial scales by combining hydraulic modelling results (based on precipitation data, a high resolution laser scanner digital surface model (DSM) and sewer system specifications) and building type-specific depth-damage functions.

Heavy rain in the urban region of Dresden caused severe damage to residential buildings. However, private homeowners usually underestimate its adverse consequences. Therefore, they have often not implemented any risk reduction measures. To overcome that obstacle, the city administration intends to visualise local hazard data and to provide building-specific vulnerability information as an important “lever” to raise people’s awareness. For this purpose, the administration has set up a digital 3D city model in CityGML format.

Up to now, there is less systematised knowledge available about risk reduction measures on building scale. Hence, the paper describes three sub-cases, embedded in the 3D city model, that contain about 750 LoD4 buildings. LoD4 provides the option to represent even the interior structure of a building and allows to visualise all vulnerable building elements in case of water intake due to heavy rain. This approach shall trigger private investments to reduce the negative consequences to a tolerable level and towards more resilient buildings.