Introduction to pond load

Ponding of rainwater is a phenomenon that occurs during a heavy rainfall on slender flat roofs. The water flows to the lowest point of the structure. Because the rainfall is excessively intensive, the drains cannot drain the water. Thus the water stays at the same place and the water level raises until the level of emergency drains is reached. Before that however the structure deforms. Due to the deformation more water flows to the lowest pond (= ponding of water also known as water accumulation) and the structure deformation increases, thus more water ... , thus larger deformation..., etc.

The described situation occurs mainly in the combination of flat roofs, roofs with slender roof structures, large area roofs.

Since the collapse of view roofs in 2002, the ponding of rainwater is a hot issue in the Netherlands.